bluuebunny/crossref_metadata_2025 huggingface dataset:
Dopamine as a Novel Antimigration and Antiproliferative Factor of Vascular Smooth Muscle Cells Through Dopamine D1-Like Receptors
Authors: Yasunari Kenichi , Kohno Masakazu , Hasuma Tadayoshi , Horio Takeshi , Kano Hiroaki , Yokokawa Koji , Minami Mieko , Yoshikawa Junichi
Published: June 2011

Abstract
Vascular smooth muscle cell (VSMC) migration and proliferation are believed to play key roles in atherosclerosis. To elucidate the role of vascular dopamine D1-like receptors in atherosclerosis, the effects of dopamine and specific D1-like agonists SKF 38393 and YM 435 on platelet-derived growth factor (PDGF) BB-mediated VSMC migration and proliferation were studied. We observed that cells stimulated by PDGF-BB (5 ng/mL), showed increased migration and proliferation. These effects were prevented by coincubation with dopamine, SKF 38393, or YM 435 (1 to 10 μmol/L), and this prevention was reversed by Sch 23390 (1 to 10 μmol/l), a specific D1-like antagonist. These actions are mimicked by forskolin (1 to 10 μmol/L), a direct activator of adenylate cyclase and 8-bromo-cAMP at 0.1 to 1 mmol/L and are blocked by a specific protein kinase A inhibitor,
N
-[2-(
p
-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide (H 89), but not blocked by its negative control,
N
-[2-(
N
-formyl)-
p
-chlorociannamylamino)ethyl]-5-isoquinoline sulfonamide (H 85). PDGF-BB (5 ng/mL)-mediated activation of phospholipase D, protein kinase C, and mitogen activated protein kinase activity were significantly suppressed by coincubation with dopamine. These results suggest that vascular D1-like receptor agonists inhibit migration and proliferation of VSMC, possibly through protein kinase A activation and suppression of activated phospholipase D, protein kinase C, and mitogen-activated protein kinase activity.
Cross-Trait Familial Resemblance for Body Fat and Blood Lipids: Familial Correlations in the Quebec Family Study
Authors: Pérusse Louis , Rice Treva , Després J. P. , Rao D. C. , Bouchard Claude
Published: June 2011

Abstract
In an attempt to better understand the genetic basis of the metabolic syndrome, we have undertaken a series of studies on the familial aggregation in the clustering of the coronary heart disease risk factors which characterize this syndrome. In the present study, the hypothesis of shared genetic (pleiotropy) and/or environmental factors between body fat and blood lipids is investigated by examining cross-trait (eg, father’s body fat with his son’s blood lipid) familial resemblance between 4 indicators of body fat (body mass index [BMI], sum of 6 skin folds [SF6]) and fat distribution (the ratio of the trunk to extremity skin folds adjusted [TER-sf] and unadjusted [TER] for SF6), and 5 blood lipid variables (total cholesterol [CH], triglycerides [TG], cholesterol associated with high-density lipoproteins [HDL], the CH/HDL ratio and the difference between CH and HDL [CH-HDL]) measured in 1239 individuals from 309 families participating in the Quebec Family Study. A bivariate correlation model was used to obtain maximum likelihood estimates of cross-trait spouse, parent-offspring, and sibling correlations after adjustment of body fat and lipid data for the effects of age, separately in the four sex-by-generation groups. Likelihood ratio tests revealed the presence of significant (
P
<.05) cross-trait resemblance between body fat (BMI and SF6) and all lipid traits except CH and also between fat distribution (TER and TER-sf) and CH/HDL and CH-HDL. Only sibling cross-trait correlations were significant for all body fat-lipid pairs of measures, with bivariate familiality estimates (ie, shared genetic and/or environmental factors) ranging from 8% to 40%. Although the hypothesis of genetic pleiotropy cannot be ruled out from the pattern of cross-trait correlations found in the present study, we conclude that environmental factors shared within sibships are probably more important than common genes in determining the covariation between body fat and blood lipids.
Interaction of Diet and Genes in Atherogenesis Report of an NHLBI Working Group
Authors: Tall Alan , Welch Carrie , Applebaum-Bowden Deborah , Wassef Momtaz
Published: June 2011

AbstractRecent advances in genetics and information emerging from the Human Genome Project make it feasible to examine the importance of dietary-genetic interactions in the development of atherosclerosis. In the opinion of the Working Group, three approaches are necessary to examine this concern. The first approach utilizes animal models to map and identify candidate genes involved in dietary responsiveness and atherogenesis. The second approach involves the evaluation of these genes in specific physiological processes involved in dietary responsiveness and atherogenesis. Finally, the third approach is to extend the studies performed in animal models to human populations using linkage or association studies.
Differential Effects of Extracellular Mg
2+
on Thrombin-Induced and Capacitative Ca
2+
Entry in Human Coronary Arterial Endothelial Cells
Authors: Yoshimura Mitsuisa , Oshima Tetsuya , Matsuura Hideo , Inoue Toshiaki , Kambe Masayuki , Kajiyama Goro
Published: June 2011

Abstract
Receptor-mediated and capacitative Ca
2+
entry are the primary Ca
2+
entry pathways in endothelial cells (ECs). The mechanisms for Ca
2+
entry via these pathways have not been fully elucidated. In this study, the effect of low and high external Mg
2+
concentrations on these Ca
2+
entry pathways was examined in human coronary arterial ECs. External Mg
2+
concentration did not affect cytosolic free Mg
2+
concentration. After exposure to thrombin in Ca
2+
-free medium, addition of Ca
2+
to the medium caused a rise in cytosolic free Ca
2+
concentration ([Ca
2+
]i), indicating thrombin-induced Ca
2+
influx. Thrombin-induced Ca
2+
influx was inhibited by not only low but also high external Mg
2+
concentrations. After depletion of endoplasmic Ca
2+
stores by thapsigargin, addition of Ca
2+
to the medium induced an increase in [Ca
2+
]i, indicating capacitative Ca
2+
entry. Capacitative entry was found to be accelerated by low external Mg
2+
and inhibited by high external Mg
2+
concentration. Results suggest that receptor-mediated Ca
2+
influx requires external Mg
2+
but is inhibited by increased external Mg
2+
concentrations and that capacitative Ca
2+
entry is reduced by external Mg
2+
in human coronary arterial ECs.
Dietary Fish Oil (4 g Daily) and Cardiovascular Risk Markers in Healthy Men
Authors: Marckmann Peter , Bladbjerg Else-Marie , Jespersen Jørgen
Published: June 2011

AbstractSome epidemiological observations indicate that 1 to 2 weekly servings of fish prevent ischemic heart disease (IHD). This might be explained by an effect of the very-long-chain n-3 polyunsaturated fatty acids (n-3 VLCPUFA) of fish oil on lipid metabolism and/or the hemostatic system, both involved in IHD development. We studied the effect of incorporating natural fish oil (4 g daily equivalent to 0.91 g n-3 VLCPUFA and corresponding to one to two weekly servings of fatty fish) into the diet in a 4-week parallel, randomized, and double-blind trial of 47 healthy males aged 29 to 60 years. Sunflower oil was used as placebo. The fish oil had no significant effect on plasma lipids, apolipoproteins, lipoprotein(a), blood coagulation FVII, fibrinogen, endogenous fibrinolysis, β-thromboglobulin, von Willebrand factor, glucose, or insulin in fasting blood samples. In nonfasting samples (n=19), fish oil was associated with an approximately 30% decline in plasma triglycerides (P<.02) and a 9% decline in FVII protein (P<.05), whereas FVII coagulant activity and fibrinolysis were unaffected. In conclusion, our findings indicate that lowering of postprandial triglycerides is the only n-3 VLCPUFA effect that could contribute to primary prevention of IHD in healthy middle-aged men as assessed by currently measurable lipid and hemostatic risk markers.
The Watanabe Heritable Hyperlipidemic Rabbit Is a Suitable Experimental Model to Study Differences in Tissue Response Between Intimal and Medial Injury After Balloon Angioplasty
Authors: Takagi Masahiko , Ueda Makiko , Becker Anton E. , Takeuchi Kazuhide , Takeda Tadanao
Published: June 2011

Abstract
The study evaluates whether the Watanabe heritable hyperlipidemic (WHHL) rabbit is an adequate model to study mechanisms that underlie differences in tissue response after postangioplasty injury. Postangioplasty studies of human coronary arteries have revealed that healing and restenotic processes differ depending on whether the laceration is limited to the atherosclerotic plaque or whether injury extends into the media. Forty-five homozygous WHHL rabbits underwent percutaneous transluminal angioplasty of the left subclavian artery. The inflated arterial segment was studied histologically at 3, 7, 14, 28, and 56 days, using conventional and immunohistochemical techniques to identify macrophages, smooth muscle cell (SMC) phenotypes, and cell proliferation. Electron microscopy was done to study reendothelialization. There were marked differences in response between those segments with medial injury and those with injury limited to the atherosclerotic plaque tissues. The latter category shows a distinct retardation in redifferentiation of SMCs, confirming previous observations in human coronary arteries. In these segments, moreover, cell proliferation occurred mainly in macrophages and spindle cells. Medial injury showed a more florid fibrocellular response, as in human coronary arteries, with cell proliferation initially confined to areas with dedifferentiated SMCs in the preexistent media and, once neointimal tissue was formed, among spindle cells also. The similarities with the repair processes encountered in postangioplasty human coronary arteries suggest that the WHHL rabbit is an adequate model to study differences in the response related to different types of angioplasty injury.
Intravascular Magnetic Resonance Imaging of Aortic Atherosclerotic Plaque Composition
Authors: Correia Luis C. L. , Atalar Ergin , Kelemen Mark D. , Ocali Ogan , Hutchins Grover M. , Fleg Jerome L. , Gerstenblith Gary , Zerhouni Elias A. , Lima Joao A. C.
Published: June 2011

Abstract
Magnetic resonance imaging (MRI) may be an excellent tool to define atherosclerotic plaque composition, but surface MRI (SMRI) suffers from a low signal-to-noise ratio and low resolution of arterial images. Intravascular MRI (IVMRI) represents a potential solution for acquiring high-quality in vivo images of atherosclerotic plaques. Isolated segments of 11 thoracic human aortas obtained at autopsy were imaged by IVMRI using an intravascular receiver catheter coil designed and built at our institution. Images obtained by IVMRI were compared with corresponding images obtained by SMRI and with histopathological aortic cross sections. The intensity of intimal thickness and plaque components was graded by IVMRI and histopathology using a score of 1 for mild, 2 for moderate, and 3 for severe intensity. IVMRI had an agreement of 75% with histopathology in fibrous cap grading (37.5% expected, κ=0.60,
P
<0.001) and of 74% in necrotic core grading (39% expected, κ=0.57,
P
<0.001). Intraplaque calcification was correctly graded by IVMRI in six of the eight plaques in which histopathology recognized calcium. The analysis of intimal thickness showed 80% agreement between IVMRI and histopathology (52% expected, κ=0.59,
P
<0.001). IVMRI image features were similar to those of SMRI. In addition, IVMRI accurately determined atherosclerotic plaque size in comparison with histopathology and SMRI (slope=1.25 cm
2
,
r
=0.99,
P
<0.001 for luminal area by IVMRI vs histopathology; slope=0.97 cm
2
,
r
=0.996,
P
<0.001 for luminal area by IVMRI vs SMRI). IVMRI has the potential to provide important prognostic information in patients with atherosclerosis because of its ability to accurately assess both plaque composition and size.
The Severity of Coronary Atherosclerosis in Type 2 Diabetes Mellitus Is Related to the Number of Circulating Triglyceride-Rich Lipoprotein Particles
Authors: Tkác̆ Ivan , Kimball Brian P. , Lewis Gary , Uffelman Kristine , Steiner George
Published: June 2011

Abstract
The presence or absence of coronary artery disease (CAD) in diabetic patients has been related to the level of circulating plasma lipoproteins. This study examines whether there is a relationship between the actual severity of CAD and the plasma concentration of major classes of plasma lipoproteins (HDL, LDL, triglyceride-rich lipoproteins (TRL), and their Sf 12 to 60 and Sf 60 to 400 subfractions), particularly the numbers of lipoprotein particles, in men and women with type 2 diabetes. 174 diabetic patients (136 men, 38 women) who underwent angiography were studied. Nine specific coronary segments were scored. The population was divided into tertiles according to the angiographic severity of their coronary disease: mild CAD: coronary score 1 to 10; moderate CAD: coronary score 11 to 13; or severe CAD: coronary score 14 to 22. The main findings were that the numbers of particles (as reflected by the apoB levels) of the TRL were greater in those with moderate and severe disease than in those with mild disease (
P
=.001). There was a significant correlation between the coronary score and the apoB in TRL (
P
=.006). There were parallel but nonsignificant changes in triglyceride levels. ApoA-I was lower in patients with moderate and severe disease (
P
=.01). These differences were more striking in women than they were in men. There were no differences in plasma, LDL, or HDL cholesterol or in LDL apoB or Lp(a). Multiple linear regression analysis, when adjusted for sex, age, and BMI, showed that three lipid variables (TRL apoB, LDL cholesterol, and plasma apoA-I) significantly and independently predicted the coronary score. This study demonstrates that in type 2 diabetes, the severity of angiographically evaluated CAD is positively related to the numbers of TRL particles in the plasma. This relationship is stronger in women than in men, and it is independent of HDL and LDL.
Tamoxifen Inhibits Arterial Accumulation of LDL Degradation Products and Progression of Coronary Artery Atherosclerosis in Monkeys
Authors: Williams J. Koudy , Wagner Janice D. , Li Zhang , Golden Deborah L. , Adams Michael R.
Published: June 2011

Estrogen replacement therapy reduces the risk of coronary heart disease in postmenopausal women and inhibits progression of coronary artery atherosclerosis in monkeys. Tamoxifen is a nonsteroidal compound with mixed estrogen agonist and antagonist properties. Its antagonist activity is useful in chemotherapy of breast cancer and may have protective effects on plasma lipid concentrations, but its effects on atherogenesis have not been defined. The goal of this study was to examine the effect of tamoxifen on plasma lipids, arterial and hepatic LDL metabolism, and progression of coronary artery atherosclerosis in surgically postmenopausal female monkeys. Thirty-five monkeys were fed an atherogenic diet containing 1.3 mg·kg−1·d−1tamoxifen (equivalent to the usual dose of 20 mg/d given to women). Thirty-one monkeys were fed the same atherogenic diet with no tamoxifen. Ten monkeys from each treatment group were fed the test diets for 12 weeks to examine the short-term effects of tamoxifen on arterial LDL metabolism. The rest of the monkeys were fed the test diets for 3 years to study the long-term effects of tamoxifen on development of atherosclerosis. In the short term, tamoxifen inhibited the rate of arterial accumulation of LDL degradation products overall (P=.03) and decreased hepatic cholesterol content (P=.003). In the long term, tamoxifen increased plasma concentrations of triglycerides (0.60±0.67 versus 0.23±0.02 mmol/L,P=.001) and reduced average LDL molecular weight (5.3±0.2 versus 4.8±0.1 g/μmol,P=.004) but had no effects on plasma total, LDL, or HDL cholesterol concentrations. Coronary artery atherosclerosis (intimal area, mean±SEM) was 0.25±0.06 mm2in control monkeys and 0.12±0.03 mm2in tamoxifen-treated monkeys (P=.057). We conclude that tamoxifen has antiatherogenic effects that may be modulated in part through direct effects on arterial LDL metabolism.
Coordinated Effects of Fibroblast Growth Factor-2 on Expression of Fibrillar Collagens, Matrix Metalloproteinases, and Tissue Inhibitors of Matrix Metalloproteinases by Human Vascular Smooth Muscle Cells
Authors: Pickering J. Geoffrey , Ford Carol M. , Tang Bao , Chow Lawrence H.
Published: June 2011

AbstractFibroblast growth factor-2 (FGF-2) is an established mediator of smooth muscle cell (SMC) proliferation after vascular injury. However, the influence of FGF-2 on collagen fiber remodeling, which may be a prerequisite for vascular SMC accumulation, is not well understood. We determined that FGF-2 almost completely abrogated the formation of immunodetectable type I collagen fibers in the extracellular matrix of cultured human vascular SMCs. This was associated with reduced expression of proα-chains for types I and III collagen, as assessed by Western blot analysis, and a corresponding reduction in collagen synthesis. Densitometry of Northern blots indicated a potent reduction of mRNA encoding proα-chains for types I and III collagen and a minor reduction in mRNA for proα-chains for type V collagen. Interstitial collagenase (MMP-1), which is required for degradation of collagen types I and III, was not expressed by SMCs under basal culture conditions, but expression was induced by FGF-2, with a potent, dose-dependent increase in MMP-1 protein in conditioned medium. Metalloproteinase inhibitors TIMP-1, TIMP-2, and TIMP-3 were expressed by unstimulated SMCs and were differentially regulated by FGF-2. TIMP-1 expression increased modestly, TIMP-2 expression was repressed, and TIMP-3 was relatively unaffected. The net effect on substrate degradation, as assessed by zymography of conditioned media, was induction of MMP-1 lytic activity by FGF-2, with no effect on the activity of MMP-2, MMP-3, or MMP-9. These data indicate that stimulation of human SMCs with FGF-2 establishes a phenotype in which collagen fiber production is repressed and the capacity for fiber degradation activated. This coordinated response may be critical for SMC accumulation during vascular remodeling as well as atherosclerotic plaque destabilization.
Socioeconomic Status and Progression of Carotid Atherosclerosis
Authors: Lynch John , Kaplan George A. , Salonen Riitta , Salonen Jukka T.
Published: June 2011

Abstract
Socioeconomic status (SES) is importantly associated with cardiovascular morbidity and mortality, but no information exists on the relationship between SES and progression of atherosclerotic vascular disease. We investigated the association between education and income and the 4-year progression of carotid atherosclerosis in a population-based sample of Finnish men. Data from the Kuopio Ischemic Heart Disease Risk Factor Study were used to estimate changes in maximum and mean intima-media thickness (IMT) and maximum plaque height across levels of SES in 1022 men. Associations between SES and atherosclerotic progression were examined in relation to risk factors and stratified by baseline levels of atherosclerosis and prevalent ischemic heart disease (IHD). There were significant, inverse, graded relationships between levels of education and income for all three progression measures, which were largely unaffected by risk factor adjustment. For education, the age- and baseline IMT–adjusted maximum progression for those with primary schooling or less was 0.28 mm and for those who graduated from high school, 0.24 mm (
P
=.05). Compared with the lowest SES group, men with the highest SES had 14% to 29% less atherosclerotic progression, depending on the measure used. Associations of the same magnitude were evident in subgroups without advanced baseline IMT and in men who were free of IHD. These results show that men with poor education and low income have significantly greater progression of carotid atherosclerosis than men with more advantages. The findings strengthen the contention that SES plays a significant role early in the atherosclerotic disease process and that reducing the burden of atherosclerotic vascular disease associated with lower SES will require approaches that focus on all stages of the life course.
Gender Differences in the Relationships Between Plasma Plasminogen Activator Inhibitor-1 Activity and Factors Linked to the Insulin Resistance Syndrome in Essential Hypertension
Authors: Toft Ingrid , Bønaa Kaare H. , Ingebretsen Ole C. , Nordøy Arne , Birkeland Kåre I. , Jenssen Trond
Published: June 2011

Abstract
Impaired fibrinolysis due to elevated levels of plasma plasminogen activator inhibitor type 1 (PAI-1) is a risk factor for thromboembolic disease. Hypertension, obesity, derangements in lipid and glucose homeostasis, and elevated levels of PAI-1 are features of the insulin resistance syndrome. The interrelationships between PAI-1 and the metabolic disturbances seen in this condition are unsettled. We investigated the associations between PAI-1 activity and components of the insulin resistance syndrome in 53 men and 31 women with untreated hypertension. In men, PAI-1 activity correlated significantly with plasma glucose (
r
=.41,
P
=.002), insulin sensitivity (
r
=−.35,
P
=.01), and insulin-induced suppression of nonesterified fatty acid (NEFA) (
r
=−.43,
P
=.007). Plasma glucose and NEFA suppression were independently associated with PAI-1 activity in a multivariate analysis. In women, PAI-1 activity correlated with body mass index (
r
=.62,
P
=.0005), waist-to-hip ratio (
r
=.75,
P
=.0001), plasma glucose (
r
=.50,
P
=.007), insulin (
r
=.49,
P
=.009), proinsulin (
r
=.57,
P
=.002), C-peptide (
r
=.60,
P
=.0009), insulin sensitivity (
r
=−.74,
P
=.0001), NEFA suppression (
r
=−.64,
P
=.003), and triglycerides (
r
=.58,
P
=.001). In multivariate analyses, insulin sensitivity and NEFA suppression were independently associated with PAI-1 if waist-to-hip ratio was not included in the model. After introduction of waist-to-hip ratio into the model, waist-to-hip ratio was the only independent predictor of PAI-1 activity. We conclude that in women, waist-to-hip ratio, body mass index, and insulin-induced NEFA suppression are determinants for PAI-1 activity. In men, insulin-induced NEFA suppression and plasma glucose are independently associated with PAI-1 activity.
Gender-Specific Associations of the Fibrinogen Bβ 448 Polymorphism, Fibrinogen Levels, and Acute Cerebrovascular Disease
Authors: Carter Angela M. , Catto Andrew J. , Bamford John M. , Grant Peter J.
Published: June 2011

Abstract
Fibrinogen is an independent risk factor for the development of stroke. Factors influencing circulating levels of fibrinogen include age, smoking, gender, and genetic factors. The aim of this study was to determine the relationship between a polymorphism at position 448 of the Bβ fibrinogen gene, fibrinogen levels, gender, and the risk of stroke. Fibrinogen levels were determined in 305 patients with stroke, taken within 10 days of the acute event and 3 months later, and in 197 control subjects. Initial fibrinogen levels in patients (4.49 g/L) were significantly higher than at 3 months (3.85 g/L,
P
<.0001), consistent with resolution of the acute-phase response. At 3 months, levels were only significantly higher than for control subjects in the male patients (3.86 g/L versus 3.31 g/L,
P
<.0001). Fibrinogen levels were associated with Bβ 448 genotype in male patients at 3 months (1/1=3.62 g/L, 1/2+2/2=4.27 g/L,
P
=.01). There was a significant difference in the genotype distribution in female patients and control subjects (patients: 1/1=95, 1/2=34, 2/2=6; control subjects: 1/1=61, 1/2=50, 2/2=3,
P
=.008). These data suggest that the mechanisms linking fibrinogen and the development of cerebrovascular disease are different in males and females. In male patients, the increase in fibrinogen levels may be influenced by environmental factors, while in females there may be a functional difference in the fibrinogen molecule unrelated to fibrinogen levels.
Ser447stopMutation in Lipoprotein Lipase Is Associated With Elevated HDL Cholesterol Levels in Normolipidemic Males
Authors: Kuivenhoven Jan Albert , Groenemeyer Björn E. , Boer Jolanda M. A. , Reymer Paul W. A. , Berghuis Riteke , Bruin Taco , Jansen Hans , Seidell Jacob C. , Kastelein John J. P.
Published: June 2011

AbstractThis report describes the association between a frequent mutation in the lipoprotein lipase (LPL) gene and HDL cholesterol levels. It concerns a previously described defect that predicts a premature truncation of the LPL protein (447stop). We determined the frequency of this mutation in three groups of healthy men with low-, middle-, and upper-decile HDL cholesterol. The number of carriers of the 447stop allele was significantly greater in the high HDL group than in either the groups with normal HDL (P=.017) or low HDL (P<.0001). Additional functional assessment of this mutation did not reveal distinct differences between wild-type LPL and the LPL447stopprotein. In conclusion, we have shown that the 447stop mutation is associated with increased HDL cholesterol in healthy Dutch males, although the underlying mechanism remains to be elucidated. Because HDL cholesterol is strongly inversely related with CAD, this genotype might be of potential benefit to its carriers.
Variability of Plasma HDL Subclass Concentrations in Men and Women Over Time
Authors: Williams Paul T. , Dreon Darlene M. , Blanche Patricia J. , Krauss Ronald M.
Published: June 2011

Abstract
Plasma HDL subclasses were examined by gradient gel electrophoresis in repeated samples to assess variability over time. Absorbance of the protein stain was used as an index of mass concentrations at 0.01-nm intervals within five HDL subclasses: HDL
3c
(7.2 to 7.8 nm), HDL
3b
(7.8 to 8.2 nm), HDL
3a
(8.2 to 8.8 nm), HDL
2a
(8.8 to 9.7 nm), and HDL
2b
(9.7 to 12 nm). Three separate longitudinal studies of men showed that repeated samples of HDL over time were correlated most strongly within HDL
2b
, somewhat less within HDL
2a
, and more weakly within HDL
3a
, HDL
3b
, and HDL
3c
. As in men, repeated samples in women from two studies were significantly correlated within the HDL
2b
, HDL
2a
, and HDL
3b
intervals. Plasma HDL
2b
levels were significantly more stable in men than in women. Although the variability of HDL subclass measurements includes both methodological and physiological sources, differences in laboratory measurement error do not appear to explain the differences in correlations among subclasses. Specifically, analysis of 288 replications from frozen aliquots suggested that laboratory error had the least effect on correlations involving HDL
3
subclasses and only slightly greater effect on correlations involving HDL
2
subclasses. Our results suggest that for plasma sampled over time, the stability of HDL subclass levels increases with particle size. Prior reports of subclass-specific correlations between HDL and other variables (eg, diet, exercise, and other lipids) are unlikely to be artifacts of laboratory precision but could arise from subclass differences in variability that are physiological.
Induction of Nitric Oxide Synthase in the Neointima Induced by a Periarterial Collar in Rabbits
Authors: Arthur J.F. , Yin Z.L. , Young H.M. , Dusting G.J.
Published: June 2011

AbstractA Silastic collar placed around the common carotid artery of rabbits causes the formation, within 7 days, of an atheroma-like neointima containing cells with the appearance of synthetic-phenotype smooth muscle cells. Using immunohistochemistry, we detected the appearance of the cytokine-inducible form of nitric oxide synthase (iNOS, or isoform II) in the neointima of rabbits that had the collar in place for 7 or 14 days. This iNOS immunofluorescence collocalized with anti–smooth muscle myosin in the intima, indicating that it is expressed in smooth muscle cells, and iNOS was also present in a few endothelial cells in collared sections. There was no evidence of iNOS expression in the arterial wall before the neointima was apparent, that is, after only 2 days with the collar. The expression of endothelial NOS (eNOS, or isoform III) immunofluorescence was confined to the endothelial cells in control sections, as it was in collared sections with neointima at 7 and 14 days. Specific immunofluorescence for neuronal NOS (nNOS, or isoform I) was not observed in any sections. Our results suggest that nitric oxide is produced by the inducible isoform of NOS in modified smooth muscle cells of the developing neointima. Activity of iNOS might deprive the endothelium of substrate for nitric oxide production and might explain the compromised endothelium-dependent vasodilatation observed both in this model of atherosclerosis and in human coronary artery disease.
Do Plaques Grow Upstream or Downstream?
Authors: Smedby Örjan
Published: June 2011

Abstract
Although the distribution of atherosclerosis has been described, little is known about the direction of growth of plaques. In this study, 237 patients with slight or moderate atherosclerosis underwent femoral angiography twice at a 3-year interval, and the films were studied with computerized image analysis. First, atherosclerosis was measured as edge roughness, and the change in roughness of each 1-cm segment over the 3-year period was related to the edge roughness of the segments immediately upstream and downstream. On the medial side of the artery, the change in edge roughness was found to be more strongly related to the roughness values upstream than to those downstream of the segment studied. This suggests that growth in the downstream direction is more common than growth in the upstream direction. On the lateral side, more equivocal results were obtained. Atherosclerosis was also assessed by study of the cross-sectional area of the artery as a function of distance along the vessel. A mathematical model of plaque growth was formulated as a nonlinear filtering of this curve. Growth in the downstream direction was significantly (
P
<.001) more frequent than growth in the upstream direction. The findings are compatible with an atherogenic effect of fluid mechanical disturbances, such as flow separation, that may occur downstream of a stenosis.
Structural Aspects of Heparin Responsible for Interactions With von Willebrand Factor
Authors: Poletti Lawrence F. , Bird Karyn E. , Marques Dalila , Harris Robert B. , Suda Yasuo , Sobel Michael
Published: June 2011

Abstract
Unfractionated heparin (UFH) binds von Willebrand factor (vWF) and inhibits the vWF–platelet GP Ib interaction. For vWF, a heparin-binding domain has been identified, but for heparin, the structures that confer such activity are unknown. To investigate this, UFH was depolymerized by methods that yield structurally distinct fragments. The glycosaminoglycans (GAGs) produced were separated into five groups of homogeneous molecular weight (MW). Anti-Xa activity, vWF binding affinity, and vWF-dependent platelet agglutination were measured. Periodate oxidation but not heparinase digestion destroyed anti-Xa activity. At all MWs, periodate conferred greater vWF binding affinity and greater ability to inhibit platelet agglutination than heparinase. As an example, at MW 6100, the binding IC
50
was 100±19 μmol/L for a periodate-derived GAG and 527±70 μmol/L for a heparinase-derived GAG. At the same MW, the agglutination IC
50
was 17±5 μmol/L for periodate and 135±18 μmol/L for heparinase. This suggests that the disaccharide GlcNS[6S]-IdoA2S, destroyed by heparinase but not periodate, is crucial to heparin-vWF interactions. An MW dependency was also noted, with a minimum dodecasaccharide required for activity inhibition. To further investigate the heparin/vWF interaction, affinity fractionation of heparins was performed with an immobilized peptide derived from a heparin-binding domain of vWF. Disaccharide analysis of high-affinity heparins revealed an increased ratio of IdoA2S-GlcN[S/Ac]6S to IdoA2S-GlcN[S/Ac]. Affinity fractionation of oligosaccharides (MW 3500) diminished the relative content of all disaccharides except IdoA2S-GlcNS6S, which was increased. These data suggest that the disaccharide structures IdoA2S-GlcNS6S and GlcNS6S-IdoA2S are crucial to heparin/vWF interactions. Understanding the structural aspects that confer such activity may be useful in designing heparin-based antithrombotic drugs.
Expression of the PAF Receptor in Human Monocyte–Derived Macrophages Is Downregulated by Oxidized LDL
Authors: Stengel Dominique , Antonucci Micheline , Arborati Muriel , Hourton Delphine , Griglio Sabine , Chapman M. John , Ninio Ewa
Published: June 2011

AbstractHuman monocyte–derived macrophages play a major role in the initiation and progression of atherosclerotic lesions as a result of the production of a wide spectrum of proinflammatory and prothrombotic factors. Among such factors is a potent inflammatory phospholipid, platelet-activating factor (PAF), which is produced after macrophage activation. Because the cells involved in PAF biosynthesis are typically targets for the bioactions of PAF via specific cell surface receptors, we evaluated the expression of the PAF receptor in human monocyte–derived macrophages. Oxidized LDL (oxLDL) exerts multiple cellular effects that enhance lesion progression; we therefore investigated the potential modulation of expression of the macrophage PAF receptor by oxLDL. [3H]PAF bound to adherent human macrophages with aKdof 2.1 nmol/L and a Bmaxof 19 fmol/106cells; ≈5300 binding sites per cell were detected. OxLDL (100 μg protein per milliliter) induced a twofold decrease in cellular PAF binding after 3 hours at 37°C. Analysis of macrophage mRNA by reverse transcription–polymerase chain reaction (RT-PCR) revealed two forms corresponding to the PAF receptor, of which the leukocyte type (type 1 promoter) predominated. Expression of PAF receptor mRNA, evaluated by quantitative RT-PCR using an actin or a GAPDH mimic, was progressively reduced (up to 70%) by oxLDL up to 6 hours and remained low for at least 24 hours. Such downregulation was reversible after incubation of the cells for 24 hours in oxLDL-free medium. Addition of forskolin (3 μmol/L) or dibutyryl cAMP (1 mmol/L) to macrophage cultures reproduced the oxLDL-mediated inhibition of PAF receptor expression; carbamyl PAF reduced PAF binding and PAF mRNA to a similar degree (≈50%). These data demonstrate that atherogenic oxLDL downregulates the expression of both cellular PAF receptors and PAF receptor mRNA in macrophages, consistent with both a diminished bioresponse to PAF and decreased cell motility. Such diminished bioresponse to a powerful antacoid reflects the suppression of an acute inflammatory reaction, thereby leading to chronic, low-level inflammation, such as that characteristic of fatty streaks and more advanced atherosclerotic plaques.
Organ Loci of Catabolism of Short Truncations of ApoB
Authors: Zhu Xian-Feng , Noto Davide , Seip Rick , Shaish Aviv , Schonfeld Gustav
Published: June 2011

Abstract
Truncations of apolipoprotein (apo) B shorter than 3200 amino acids (3200/4536=apoB-70) do not possess the LDL receptor–recognition domain and are not recognized by altered cells with normally functioning LDL receptors. To ascertain which organs remove such truncated apoB–containing particles, we isolated apoB-31–, apoB-38.9–, and apoB-43.7–containing particles from plasmas of familial hypobetalipoproteinemia heterozygous humans by a combination of sequential ultracentrifugation and preparative electrophoresis. Particles with labeled
125
I- or
131
I-dilactitol tyramine (I-DLT), were injected into New Zealand White rabbits, along with I-DLT–apoB-100–containing LDLs, and the decay of
125
I- and
131
I-TCA–precipitated counts was followed over 24 hours. At the end of 24 hours, rabbits were anesthetized and their bodies perfused. Organs were removed and homogenized, and TCA-precipitable counts determined. Fractional catabolic rates of apoB truncation particles were two to five times greater than those of apoB-100 LDLs. ApoB truncations accumulated in adrenals at one fifth the rates of apoB-100 LDL, compatible with the functional absences of LDL receptor–recognition domains in truncated apoBs. The major organ of uptake for apoB-100-LDLs was the liver, whereas truncation particles were readily removed by the kidney (kidney: liver uptake ratios were 0.10 to 0.30 for apoB-100 LDLs and 1.03 to 3.77 for truncations). Spleens accumulated little of either apoB-100 or truncation particles, suggesting particles were not “damaged” or aggregated. Thus, the absence of >56% of the carboxyl end of apoB-100 increases the plasma clearance and redirects the organ uptake of the apoB truncation–containing lipoproteins from liver to kidney.
Codon 54 Polymorphism of the Human Intestinal Fatty Acid Binding Protein 2 Gene Is Associated With Dyslipidemias But Not With Insulin Resistance in Patients With Familial Combined Hyperlipidemia
Authors: Pihlajamäki Jussi , Rissanen Johanna , Heikkinen Sami , Karjalainen Leena , Laakso Markku
Published: June 2011

Abstract
Familial combined hyperlipidemia (FCHL) is associated with variable expression of dyslipidemias and insulin resistance. In nondiabetic Pima Indians an A to G substitution in codon 54 of the fatty acid binding protein 2 (FABP2) gene has been shown to be associated with insulin resistance. We screened the entire coding region of this gene by single-strand conformation polymorphism analysis in 24 probands (17 men and 7 women; age, 63.0±7.4 years [mean±SD]; body mass index [BMI], 27.7±4.2 kg/m
2
) who had FCHL and in 40 healthy men from a random population sample of 82 men (age, 54.0±5.0 years; BMI, 26.3±3.2 kg/m
2
). Insulin resistance was assessed with the euglycemic clamp in 58 subjects from FCHL families (14 probands with FCHL and 44 first-degree relatives of probands: 38 men and 20 women; age, 51.5±12.6 years; BMI, 25.5±3.9 kg/m
2
). We found three nucleotide substitutions in the FABP2 gene: GCT to ACT (Ala→Thr) in codon 54, GTA to GTG in codon 118, and GCGCA to GCACA in the 3′-noncoding region. Frequencies of these variants did not differ between the patients and control subjects. The Ala to Thr substitution in codon 54 was associated with a high lipid oxidation rate (
P
=.011 after adjustment for sex and family relationship), high HDL triglycerides (
P
=.042), and high LDL triglycerides (
P
=.013) but not with insulin resistance in subjects from FCHL families. The FABP2 gene is unlikely to be a major gene for FCHL, but it might affect lipid metabolism in subjects with FCHL.
Glucocorticoids Stimulate Cholesteryl Ester Formation in Human Smooth Muscle Cells
Authors: Petrichenko Igor E. , Daret Daniele , Kolpakova Galina V. , Shakhov Yuri A. , Larrue Jacky
Published: June 2011

Abstract
The aim of the present study was to investigate the effect of synthetic glucocorticoid dexamethasone (Dex) on cholesterol esterification in cultured human smooth muscle cells (SMC). In labeled SMC, Dex stimulated the esterification of [
3
H]cholesterol in a dose-dependent manner. This effect was specific for glucocorticoid hormones and could be inhibited by cycloheximide (3 ng/mL), actinomycin D (10
−5
mol/L), and the specific glucocorticoid antagonist RU 486 (10
−8
mol/L). When plasma membrane was selectively labeled with trace quantities of [
3
H]cholesterol (0.25 μCi/mL, 1 hour, 10°C), Dex (10
−8
mol/L) caused a net flux of free [
3
H]cholesterol into the cells. Moreover, Dex (10
−8
mol/L, 24 hours) stimulated the esterification of sterols, newly synthesized from [
14
C]mevalonate (10 μCi/mL, 4 hours) and lowered the amount of [
14
C]sterols susceptible for cholesterol oxidase. The incorporation of [
14
C]oleic acid into cholesteryl esters was markedly higher in Dex-pretreated SMC than in the control cells (2.1±0.07 and 1.4±0.1 pmol/h/μg protein, respectively,
P
<.01). At the time, cholesteryl ester hydrolysis in Dex-treated cells was reduced (72±8 pmol cholesteryl esters/h per milligram versus 130±10 in the control cells). HDL
3
-mediated [
3
H]cholesterol efflux was also inhibited in Dex-treated cells; moreover, HDL
3
(40 μg/mL, 24 hours) had practically no effect on [
3
H]cholesteryl ester content in Dex-treated SMC but caused a 50% reduction of [
3
H]cholesteryl esters in the control cells. Thus, in human SMC glucocorticoids alter the redistribution of cholesterol between the pools of free and esterified cholesterol, paralleled by the change in acyl coenzyme A:cholesteryl acyltransferase and neutral cholesteryl ester hydrolase activities, leading to the impaired HDL
3
-mediated cholesterol efflux.
Myosin Gene Expression and Cell Phenotypes in Vascular Smooth Muscle During Development, in Experimental Models, and in Vascular Disease
Authors: Sartore Saverio , Chiavegato Angela , Franch Rafaella , Faggin Elisabetta , Pauletto Paolo
Published: June 2011

Abstract
In the aortic wall of mammalian species, the maturation phase of smooth muscle cell (SMC) lineage is characterized by two temporally correlated but opposite regulatory processes of gene expression: upregulation of SM type SM2 myosin isoform and downregulation of brain (myosin heavy chain B)- and platelet (myosin heavy chain A
pla
)-type nonmuscle myosins. Using the myosin isoform approach to study vascular SMC biology, we have shown (1) a marked SMC heterogeneity in adult arterial vessels, ie, coexistence of an “immature” and a fully differentiated SMC population; and (2) the propensity of the immature type SMC population to be activated in experimental models and human vascular diseases that are characterized by proliferation and migration of medial SMCs into the subendothelial space.
Changes With Age in the Influence of Endogenous Nitric Oxide on Transport Properties of the Rabbit Aortic Wall Near Branches
Authors: Forster Beverley A. , Weinberg Peter D.
Published: June 2011

Abstract
Uptake of circulating albumin by the aortic wall is greater downstream than upstream of branches in immature rabbits, but the opposite pattern occurs in mature animals. We investigated the role of NO in determining these variations. Descending thoracic aortas of rabbits were cannulated using techniques that avoid depressurization, overstretching, and excessive fluid dynamic stresses at the endothelial surface. They were perfused in situ at a constant pressure and flow rate with oxygenated, protein-containing physiological buffer, with or without
N

ω

-monomethyl-
l
-arginine, an inhibitor of NO synthesis. Aortas were fixed 7 to 8 minutes after the addition of rhodamine-labeled albumin to this perfusate, and uptake of the tracer near intercostal ostia was measured by digital imaging fluorescence microscopy of sections through the wall. Despite the absence of pulsatile flow, blood cells, and many plasma components, patterns of transport in control experiments were the same as those occurring in vivo; uptake was greatest downstream of ostia in immature vessels and upstream in mature ones, although mean uptake was higher than previously reported. In the presence of the inhibitor, mean uptake in immature arteries was elevated threefold and the maximum tracer concentration occurred deeper in the wall, but there was no change in the fractional difference between regions. Conversely, the reverse of the control pattern of transport was observed in mature arteries exposed to the inhibitor, but there was no change in mean uptake. The reversal was almost entirely prevented by adding excess
l
-arginine to the perfusate and was largely stereospecific. Endogenous NO thus appears to determine the mature pattern of transport near branches and helps to maintain the barrier function of the immature wall.
Shear Stress as an Inhibitor of Vascular Smooth Muscle Cell Proliferation
Authors: Ueba Hiroto , Kawakami Masanobu , Yaginuma Toshio
Published: June 2011

Abstract
We examined whether shear stress can inhibit vascular smooth muscle cell (VSMC) proliferation in vitro directly. Human VSMCs were exposed to fluid flow for 24 hours using a cone-plate apparatus, and their proliferation was inhibited significantly by shear stresses of 1.4 and 2.8 Pa (14 and 28 dyne/cm
2
), according to the magnitude. Next, we investigated whether transforming growth factor-β1 (TGFβ1), which is known to be an important cytokine that suppresses VSMC proliferation, is the predominant mediator of shear-induced inhibition of VSMC growth. After exposure of VSMCs to shear stress (2.8 Pa) for 24 hours, gene expression of TGFβ1 and, interestingly, tissue-type plasminogen activator, which converts plasminogen to plasmin, an activator of TGFβ1, increased twofold and fivefold, respectively. The levels of both latent and active forms of TGFβ1 in conditioned media of VSMCs exposed to fluid flow increased significantly. An anti-TGFβ1 antibody reversed shear-induced inhibition of VSMC growth significantly. We concluded that shear stress inhibited VSMC proliferation in vitro and this inhibition was mediated predominantly by TGFβ1 in an autocrine manner. These data suggest that shear stress plays an important role as an inhibitor of atherogenesis in endothelium-desquamated lesions.
Effects of Fluvastatin on Leukocyte–Endothelial Cell Adhesion in Hypercholesterolemic Rats
Authors: Kimura Masaaki , Kurose Iwao , Russell Janice , Granger D. Neil
Published: June 2011

Abstract
The overall objective of this study was to determine whether peroral treatment with the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin influences the leukocyte–endothelial cell adhesion (LECA) observed in postcapillary venules of hypercholesterolemic rats. Rats were fed either normal chow or a chow supplemented with 1% cholesterol for 10 days. Leukocyte adherence and extravasation, leukocyte rolling velocity, red blood cell velocity, and vessel diameter were monitored in mesenteric venules superfused with either 100 nmol/L platelet-activating factor (PAF) or 20 nmol/L leukotriene B
4
(LTB
4
). Hypercholesterolemic rats exhibited an exaggerated LECA response compared with their normocholesterolemic counterparts. In hypercholesterolemic rats, treatment with fluvastatin significantly attenuated the leukocyte-adherence responses to PAF and LTB
4
as well as the leukocyte emigration response to LTB
4
. Fluvastatin treatment also inhibited the PAF- and LTB
4
-induced reductions in leukocyte rolling velocity. These findings indicate that fluvastatin blunts the inflammatory responses elicited in postcapillary venules by lipid mediators.