bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Determinants of Oxidized Low-Density Lipoprotein–Induced Leukocyte Adhesion and Microvascular Dysfunction
Authors: Liao Lianxi , Starzyk Ruth M. , Granger D. Neil
Published: June 2011

AbstractOxidized low-density lipoproteins (oxLDL) have been implicated in the leukocyte recruitment and microvascular dysfunction associated with atherosclerosis. The objectives of this study were to define the adhesion molecules that mediate oxLDL-induced leukocyte–endothelial cell adhesion and to determine whether leukocyte–endothelial cell adhesion contributes to the endothelial barrier dysfunction elicited by oxLDL. Leukocyte–endothelial cell adhesion and emigration, albumin extravasation, and mast cell degranulation were monitored in rat mesentery in response to native LDL (nLDL) or copper-oxidized LDL (oxLDL). Intra-arterial infusion of oxLDL but not nLDL elicited increases in leukocyte adherence and emigration, mast cell degranulation, and albumin leakage. The oxLDL-induced leukocyte adherence/emigration was attenuated by pretreatment with monoclonal antibodies directed against CD11/CD18, intercellular adhesion molecule-1, P-selectin, and L-selectin but not by pretreatment with a nonbinding monoclonal antibody. The albumin leakage and mast cell degranulation responses were attenuated by all of the same monoclonal antibodies except L-selectin. In addition, a peptide previously shown to inhibit leukocyte–endothelial cell adhesion in vitro also attenuated leukocyte adherence and mast cell degranulation in this model. These findings implicate CD11/CD18, L-selectin, intercellular adhesion molecule-1, and P-selectin in the leukocyte recruitment elicited by oxLDL and invoke a role for adherent leukocytes in the accompanying increase in mast cell degranulation and albumin leakage.
The Relationship of Soluble Fibrin and Cross-linked Fibrin Degradation Products to the Clinical Course of Myocardial Infarction
Authors: Lee L. Veronica , Ewald Gregory A. , McKenzie Clark R. , Eisenberg Paul R.
Published: June 2011

AbstractRecently, increases in the plasma concentration of soluble fibrin (SF) have been suggested to be sensitive and specific for myocardial infarction (MI). However, the relationship between elevations in the SF concentration and the onset of symptoms and clinical course of MI is unknown. In addition, there are no data regarding the relationship between SF concentrations and concentrations of other markers of procoagulant (fibrinopeptide A [FPA]) and fibrinolytic (cross-linked fibrin degradation products [XL-FDPs]) activity in patients with MI. In this study, concentrations of SF were measured with a novel antigen-based assay for 93 MI patients and 29 control subjects, and the relationship between SF concentrations and those of XL-FDPs and FPA was determined. Increases in SF, FPA, and XL-FDP concentrations were documented in 55.9%, 45.2%, and 73.9%, respectively, of patients with MI, but there was no relationship between the concentrations of these markers. Increases in the concentration of SF or XL-FDPs did not show a relationship to increases in the concentration of FPA. Concentrations of XL-FDPs but not of SF were elevated to a greater extent in patients with MI complications (defined as death, ventricular arrhythmia, severe congestive heart failure, or mural thrombus). Increases in SF and XL-FDPs were not sensitive enough for the diagnosis of MI, but increased concentrations of XL-FDPs appear to predict those patients who are at higher risk for MI-related complications.
Cardiovascular Risk Factors and Hyalinization of Renal Arterioles at Autopsy
Authors: Burchfiel Cecil M. , Tracy Richard E. , Chyou Po-Huang , Strong Jack P.
Published: June 2011

Abstract
Nephrosclerosis, commonly found in subjects with hypertension and diabetes, is marked by hyalinization of arterioles and fibroplasia of small arteries in the renal cortex. Cardiovascular risk factors that predicted subsequent hyalinization of renal arterioles at autopsy were identified, using data from the Honolulu Heart Program, a prospective epidemiological study of cardiovascular disease (CVD) in Japanese-American men. Among 8006 participants at baseline, 1381 died between 1965 and 1982; 285 of these had a protocol autopsy, and 150 had assessments of arteriolar hyalinization from renal tissue. Subjects were categorized into four groups on the basis of the number of hyalinized arterioles per square centimeter of renal tissue, and CVD risk factor levels and proportions were compared across these groups with the use of general linear models and logistic regression. Multivariate assessment using logistic regression demonstrated that diastolic blood pressure (DBP) and glucose level were positively associated and alcohol intake was negatively associated with an elevated degree of renal arteriolar hyalinization, independent of other CVD risk factors. The odds ratios for elevated hyalinization associated with a 10–mm Hg increase in DBP, a 20-mg/dL increase in glucose level, and a 30-mL/d increase in alcohol intake were 1.97 (95% confidence interval [CI]=1.24-3.12), 1.23 (95% CI=1.07-1.41), and 0.24 (95% CI=0.11-0.55), respectively. Associations were similar when prevalent cases of CVD were excluded and when autopsy selection bias was taken into account. Renal arteriolar hyalinization was also more strongly associated with atherosclerosis in the larger cerebral vessels (Spearman's
r
=.59,
P
<.001) than in the coronary arteries (
r
=.16,
P
=.073) and aorta (
r
=.24,
P
=.022). Hyalinization was significantly related to cardiovascular-renal mortality, and this association was accounted for by other CVD risk factors. These findings suggest that blood pressure, glucose level, and alcohol intake are independent predictors of hyalinization in renal arterioles and that this type of renal vasculopathy may be a marker for atherosclerosis in other vascular regions, particularly the cerebral vessels. The protective association involving alcohol and the possibility that renal arteriolar hyalinization may be an indicator of cerebral atherosclerosis may warrant investigation in other populations.
Megakaryocyte Ploidy and Platelet Changes in Human Diabetes and Atherosclerosis
Authors: Brown Angie S. , Hong Ying , de Belder Adam , Beacon Heather , Beeso Julie , Sherwood Roy , Edmonds Michael , Martin John F. , Erusalimsky Jorge D.
Published: June 2011

Abstract
Altered platelet morphology and function have been reported in patients with diabetes. They are likely to be associated with the pathological processes and increased risk of vascular disease seen in these patients. Mean platelet volume (MPV), platelet count, and megakaryocyte (MK) ploidy (DNA content) were measured in (1) nondiabetics with normal coronary arteries, (2) nondiabetics with coronary artery atherosclerosis, (3) diabetics without evidence of vascular complications, and (4) diabetics with vascular disease. The platelet count (±SD) was increased in all groups but only significantly in the diabetics with vascular disease (236±65 versus 250±54 versus 257±64 versus 295±90 [
P
≤.05]×10
9
/L, for groups I, II, III, and IV, respectively). The MPV was significantly increased in patients with atherosclerosis (7.0±0.4 versus 8.0±1.2 [
P
≤.05] versus 7.2±0.9 versus 8.1±0.9 [
P
≤.05] fL). Geometric mean MK ploidy was significantly increased in all groups compared with controls (16±1.5 versus 18.7±1.8 [
P
≤.05] versus 19.8±1.6 [
P
≤.05] versus 20.1±2.7 [
P
≤.05]). Furthermore, some patients with vascular disease and/or diabetes had a modal ploidy shift from 16 (the normal mammalian modal ploidy) to 32, with a concomitant reduction of MKs in the 8 and 16 ploidy classes. This shift was seen particularly in the diabetics with vascular disease (
P
=.007). Interleukin-6 (IL-6) levels were measured and were elevated in patients with atherosclerosis; the highest levels were found in the diabetic patients (0.7±0.9 versus 5.3±5.5 [
P
≤.05] versus 2.5±2.8 versus 6.7±5.5 [
P
≤.05] ng/L). In the diabetic patients with atherosclerosis, fibrinogen levels were also increased (2.85±0.76 versus 3.34±1.32 versus 2.43±1.50 versus 5.59±1.72 [
P
≤.05] g/L). Furthermore, IL-6 levels correlated with MK ploidy (
r
=.45,
P
=.009) and fibrinogen levels (
r
=.5,
P
=.0001). This study demonstrates that patients with vascular disease, particularly diabetics, have an altered MK ploidy distribution, showing a shift toward higher ploidy in association with an increased platelet mass (count×volume). Changes in platelets in diabetes probably reflect MK changes, which themselves are a response to systemic change.
Association of the Fatty Acid Composition of Serum Phospholipids With Hemostatic Factors
Authors: Salomaa Veikko V. , Salminen Irma , Rasi Vesa , Vahtera Elina , Aro Antti , Myllylä Gunnar
Published: June 2011

Abstract
It has been suggested that the fatty acid composition of serum phospholipids is an independent risk factor for cardiovascular disease. We examined the association of the fatty acid composition of serum phospholipids with fibrinogen, factor VII antigen (FVII:Ag), factor VII coagulant activity (FVII:C), plasminogen, and lipoprotein(a) [Lp(a)] in 338 men and 363 women 45 to 64 years old. Palmitic acid, the most abundant saturated fatty acid, was positively associated in univariate analyses with plasminogen, which explained 5.2% of its variance among men (
P
<.0001) and 5.8% among women (
P
<.0001). Linoleic acid, which is the most abundant polyunsaturated fatty acid, was negatively associated with plasminogen and fibrinogen. This explained 1.1% of the variance in fibrinogen among men (
P
=.04) and 3.2% among women (
P
=.0006) and 4.1% of the variance in plasminogen in both sexes (
P
<.0001). Dihomogammalinolenic acid was positively associated with FVII:Ag and explained 3.7% of its variance among men (
P
=.0003) and 4.6% among women (
P
<.0001). Furthermore, dihomogammalinolenic acid was positively and significantly associated with FVII:C, fibrinogen, and plasminogen among women but not among men. All these associations remained significant after adjustment for multiple potential confounding factors such as age, smoking, serum lipids, and body mass index. In conclusion, our findings suggest that linoleic acid, palmitic acid, and dihomogammalinoleic acid are significant independent determinants of hemostatic profile. It is not clear, however, to what extent these results reflect the effects of fatty acids on coagulation and to what extent they reflect the activity of inflammatory processes in the arteries.
Regulation of Scavenger Receptor Expression in Smooth Muscle Cells by Protein Kinase C
Authors: Mietus-Snyder Michele , Friera Annabelle , Glass Christopher K. , Pitas Robert E.
Published: June 2011

AbstractPhorbol esters increase scavenger-receptor mRNA expression and receptor activity in smooth muscle cells (SMCs). Our present results demonstrate that activation of protein kinase C (PKC) mediates this increase in receptor expression. This conclusion is based on the findings that (1) phorbol esters induced translocation of PKC-α from the cytosol to the membrane fraction; (2) PKC inhibitors blocked the effect of phorbol esters on receptor expression; (3) diacylglycerol, a physiological PKC agonist, enhanced scavenger-receptor activity; and (4) in cotransfected human SMCs, constitutively active PKC-α stimulated the expression of a reporter gene under control of the scavenger-receptor promoter. Phorbol ester treatment of SMCs increased intracellular reactive oxygen, and the increase in receptor activity was reduced 30% by the antioxidantN-acetyl cysteine (NAC), suggesting a role for reactive oxygen in phorbol ester–mediated receptor regulation. Furthermore, direct treatment of SMCs with reactive oxygen species increased scavenger-receptor activity. In rabbit SMCs, 100 μmol/L H2O2alone slightly increased scavenger-receptor mRNA and protein expression. In combination, 100 μmol/L H2O2and 10 μmol/L vanadate, which promotes formation of OH and enhances the inhibition of protein tyrosine phosphatase by H2O2, increased scavenger-receptor mRNA expression 25-fold in rabbit SMCs and 8-fold in human SMCs. NAC reduced the effect of H2O2and vanadate by 93%. The increase in SMC scavenger-receptor expression occurs at the level of gene transcription. Receptor mRNA half-life was unchanged after treatment with either phorbol esters or reactive oxygen (≈14.5 hours), and induction by phorbol esters increased SMC scavenger-receptor mRNA transcription, as determined by nuclear run-on assay. Multiple cytokines and growth factors that contribute to the generation of reactive oxygen species are present in atherosclerotic lesions. These factors may all contribute to the upregulation of SMC scavenger-receptor activity and therefore to the formation of smooth muscle foam cells.
Cholesteryl Ester Transfer Protein Activity Enhances Plasma Cholesteryl Ester Formation
Authors: Oliveira Helena C.F. , Ma Limei , Milne Ross , Marcovina Santica M. , Inazu Akihiro , Mabuchi Hiroshi , Tall Alan R.
Published: June 2011

Abstract
The plasma cholesteryl ester transfer protein (CETP) promotes the removal of HDL cholesteryl esters and is thought to stimulate reverse cholesterol transport (RCT). However, mechanisms by which CETP may stimulate RCT are poorly understood. Thus, we examined the relationship between plasma CETP expression and plasma cholesteryl ester formation in CETP transgenic (Tg) mice, hamsters, and human subjects with genetic CETP deficiency. Incubation of CETP Tg mouse plasma showed a 20% to 40% increase in plasma cholesterol esterification rate (CER,
P
<.05) compared with control mice. Injection of a neutralizing CETP monoclonal antibody (MAb) (TP2) into natural flanking region CETP Tg mice resulted in an increase in plasma free cholesterol (FC) concentration, FC/CE ratio, FC/phosphatidylcholine ratio, and hepatic CETP mRNA. In hamsters, CETP inhibition also resulted in an increase in plasma FC/phosphatidylcholine ratio and increased CETP mRNA in adipose tissue. In humans with two common CETP gene mutations (an intron 14 splicing defect and a D442G missense mutation), mean plasma CERs were 39 and 60, respectively, compared with 89 nmol·mL
−1
·h
−1
in normal subjects. By contrast, lecithin:cholesterol acyltransferase (LCAT) mass was normal in CETP-deficient subjects. MAb neutralization of CETP activity in incubated human plasma did not alter the LCAT reaction, even after supplementation with discoidal HDL and VLDL. Thus, genetic alterations in CETP levels lead to secondary changes in the plasma LCAT reaction, possibly because of remodeling of HDL by CETP acting in concert with other factors in vivo. In human genetic CETP deficiency, a moderate impairment in the plasma LCAT reaction may contribute to a defect in RCT, providing a potential mechanism to explain the recently observed excess of coronary heart disease in these subjects.
Common Genomic Variants Associated With Variation in Plasma Lipoproteins in Young Aboriginal Canadians
Authors: Hegele Robert A. , Connelly Philip W. , Hanley Anthony J.G. , Sun Fang , Harris Stewart B. , Zinman Bernard
Published: June 2011

AbstractWe hypothesized that common genomic variants would be associated with variation in lipoprotein phenotypes in young subjects. We determined genotypes ofFABP2,PON,APOC3, andAPOEin 188 aboriginal Canadians, aged 9 to 17 years. We found that 13 of 32 possible genotype-phenotype associations were significant: (1) theFABP2codon 54 genotype was associated with variation in plasma triglycerides (P=.045); (2) thePONcodon 192 genotype was associated with variation in plasma total and LDL cholesterol and apoB (P=.0099,P=.0088, andP=.016, respectively); (3) theAPOC3insulin-response-element genotype was associated with variation in plasma triglycerides, HDL cholesterol, apoA-I, the total cholesterol to HDL cholesterol ratio, and the apoB to apoA-I ratio (P=.0014,P=.0069,P=.045,P=.0021, andP=.0081, respectively); and (4) theAPOErestriction isotype was associated with variation in plasma LDL cholesterol, apoB, the total cholesterol to HDL cholesterol ratio, and the apoB to apoA-I ratio (P=.025,P=.034,P=.045, andP=.047, respectively). The average young age and relative absence of age-dependent secondary environmental factors could have eased the identification of small genetic effects on lipoprotein phenotypes in this study sample.
Relation of High TG–Low HDL Cholesterol and LDL Cholesterol to the Incidence of Ischemic Heart Disease
Authors: Jeppesen Jørgen , Hein Hans Ole , Suadicani Poul , Gyntelberg Finn
Published: June 2011

Abstract
High triglyceride (TG) and low HDL cholesterol (HDL-C) is the characteristic dyslipidemia seen in insulin-resistant subjects. We examined the role of this dyslipidemia as a risk factor of ischemic heart disease (IHD) compared with that of high LDL cholesterol (LDL-C) in the Copenhagen Male Study. In total 2910 white men, aged 53 to 74 years, free of cardiovascular disease at baseline, were subdivided into four groups on the basis of fasting concentrations of serum TG, HDL-C, and LDL-C. “High TG–low HDL-C” was defined as belonging to both the highest third of TG and the lowest third of HDL-C; this group encompassed one fifth of the population. “High LDL-C” was defined as belonging to the highest fifth of LDL-C. A control group was defined as not belonging to either of these two groups. “Combined dyslipidemia” was defined as belonging to both dyslipidemic groups. Age-adjusted incidence of IHD during 8 years of follow-up was 11.4% in high TG–low HDL-C, 8.2% in high LDL-C, 6.6% in the control group, and 17.5% in combined dyslipidemia. Compared with the control group, relative risks of IHD (95% confidence interval), adjusted for potentially confounding factors or covariates (age, body mass index, alcohol consumption, physical activity, non–insulin-dependent diabetes, hypertension, smoking, and social class), were 1.5 (1.0-2.1),
P
<.05; 1.3 (0.9-2.0),
P
=.16; and 2.4 (1.5-4.0),
P
<.01, in the three dyslipidemic groups, respectively. In conclusion, the present results showed that high TG–low HDL-C, the characteristic dyslipidemia seen in insulin-resistant subjects, was at least as powerful a predictor of IHD as isolated high LDL-C. The results suggest that efforts to prevent IHD should include intervention against high TG–low HDL-C, and not just against hypercholesterolemia.
Arterial Compliance in Obese Subjects Is Improved With Dietary Plant n-3 Fatty Acid From Flaxseed Oil Despite Increased LDL Oxidizability
Authors: Nestel Paul J. , Pomeroy Sylvia E. , Sasahara Takayuki , Yamashita Takeshi , Liang Yu Lu , Dart Anthony M. , Jennings Garry L. , Abbey Mavis , Cameron James D.
Published: June 2011

Abstract
The compliance or elasticity of the arterial system, an important index of circulatory function, diminishes with increasing cardiovascular risk. Conversely, systemic arterial compliance improves through eating of fish and fish oil. We therefore tested the value of high intake of α-linolenic acid, the plant precursor of fish fatty acids. Fifteen obese people with markers for insulin resistance ate in turn four diets of 4 weeks each: saturated/high fat (SHF), α-linolenic acid/low fat (ALF), oleic/low fat (OLF), and SHF. Daily intake of α-linolenic acid was 20 g from margarine products based on flax oil. Systemic arterial compliance was calculated from aortic flow velocity and aortic root driving pressure. Plasma lipids, glucose tolerance, and in vitro LDL oxidizability were also measured. Systemic arterial compliance during the first and last SHF periods was 0.42±0.12 (mean±SD) and 0.56±0.21 units based on milliliters per millimeter of mercury. It rose significantly to 0.78±0.28 (
P
<.0001) with ALF; systemic arterial compliance with OLF was 0.62±0.19, lower than with ALF (
P
<.05). Mean arterial pressures and results of oral glucose tolerance tests were similar during ALF, OLF, and second SHF; total cholesterol levels were also not significantly different. However, insulin sensitivity and HDL cholesterol diminished and LDL oxidizability increased with ALF. The marked rise in arterial compliance at least with α-linolenic acid reflected rapid functional improvement in the systemic arterial circulation despite a rise in LDL oxidizability. Dietary n-3 fatty acids in flax oil thus confer a novel approach to improving arterial function.
Importance of Platelets in Neutrophil Adhesion and Vasoconstriction After Deep Carotid Arterial Injury by Angioplasty in Pigs
Authors: Merhi Yahye , Provost Patrick , Guidoin Robert , Latour Jean-Gilles
Published: June 2011

Abstract
In previous studies we have shown that platelets can support neutrophil adhesion to the injured vessel wall in vitro and that neutrophils contribute to vascular tone regulation after arterial injury in vivo. In this study, we investigated the implication of platelets in neutrophil adhesion and the vasomotor response to arterial injury in vivo.
111
In-labeled neutrophil adhesion and angiographic vasoconstriction were quantified after deep carotid arterial injury by balloon angioplasty in normal (n=8), thrombocytopenic (n=7), and aspirin-treated (2 mg/kg IV, n=7) pigs. Thrombocytopenia was produced by a polyclonal antiplatelet serum that depleted circulating platelet count by 84% without influencing neutrophil count. In the control animals, neutrophil adhesion (×10
4
/cm
2
) at the site of deep arterial injury averaged 26.8±4.0 and decreased significantly to 11.5±2.3 and 11.2±2.4 in the thrombocytopenic and aspirin groups, respectively. The degree of vasoconstriction was also reduced significantly, from 55.5±3.8% in the control group to 31.4±6.2% after platelet depletion and to 23.6±4.5% in the aspirin-treated group. Neutrophil adhesion to intact noninjured adjacent arterial segments was low in all groups and was not affected by the antiplatelet serum or by aspirin. In in vitro superfusion flow chambers, neutrophil adhesion to damaged arterial segments increased in the presence of platelets in a concentration-dependent manner and was not influenced by the anti-platelet serum. This study demonstrates that platelets can modulate neutrophil adhesion to the deeply injured arterial wall and that both elements may influence the degree of postangioplasty vasoconstriction in vivo.
Human Leukemia Inhibitory Factor Upregulates LDL Receptors on Liver Cells and Decreases Serum Cholesterol in the Cholesterol-Fed Rabbit
Authors: Moran Corey S. , Campbell Julie H. , Campbell Gordon R.
Published: June 2011

Abstract
In a previous study, we found that the cytokine (human) leukemia inhibitory factor (hLIF) significantly reduced plasma cholesterol levels and the accumulation of lipid in aortic tissues of cholesterol-fed rabbits after 4 weeks of treatment. The mechanisms by which this occurs were investigated in the present study. This involved examining the effect of hLIF on (1) the level of plasma cholesterol at different times throughout the 4-week treatment and diet period; (2) smooth muscle cell (SMC) and macrophage-derived foam cell formation in vitro; and (3) LDL receptor expression and uptake in the human hepatoma cell line HepG2. At time zero, an osmotic minipump (2-mL capacity; infusion rate, 2.5 μL/h; 28 days) containing either hLIF (30 μg · kg
−1
· d
−1
) or saline was inserted into the peritoneal cavity of New Zealand White rabbits (N=24). Rabbits were divided into four groups of six animals each. Group 1 received a normal diet/saline; group 2, a normal diet/hLIF; group 3, a 1% cholesterol diet/saline; and group 4, a 1% cholesterol diet/hLIF. hLIF had no effect on the plasma lipids or artery wall of group 2 rabbits (normal diet). However, in group 4 rabbits, plasma cholesterol levels and the percent surface area of thoracic aorta covered by fatty streaks was decreased by ≈30% and 80%, respectively, throughout all stages of the 4-week treatment period. In vitro, hLIF failed to prevent lipoprotein uptake by either SMCs or macrophages (foam cell formation) when the cells were exposed to β-VLDL for 24 hours. In contrast, hLIF (100 ng/mL) added to cultured human hepatoma HepG2 cells induced a twofold or threefold increase in intracellular lipid accumulation in the medium containing 10% lipoprotein-deficient serum or 10% fetal calf serum, respectively. This was accompanied by a significant non–dose-dependent increase in LDL receptor expression in hLIF-treated HepG2 cells incubated with LDL (20 μg/mL) when compared with controls (
P
<.05) incubated in control medium alone (
P
<.05). We suggest that the hLIF-induced lowering of plasma cholesterol and tissue cholesterol levels (inhibition of fatty streak formation) in the hyperlipidemic rabbit is due in part to upregulation of hepatic LDL receptors, with resultant increased clearance of lipoprotein-associated cholesterol from the circulation. There is an additional and as-yet-unknown mechanism acting at the level of the vessel wall that appears to be affecting the process of arterial cholesterol accumulation.
PDGF Receptor Protein Tyrosine Kinase Expression in the Balloon-Injured Rat Carotid Artery
Authors: Panek Robert L. , Dahring Tawny K. , Olszewski Bronia J. , Keiser Joan A.
Published: June 2011

Abstract
Platelet-derived growth factor (PDGF) receptor gene expression has previously been demonstrated in balloon-injured rat carotid arteries to be regulated during repair of carotid injury. In the present study we showed that PDGF receptor protein expression and phosphorylation are changed over time after carotid artery injury. In control and 2-day-postinjury vessels, expression of PDGF α receptor protein was readily detectable, whereas PDGF β receptor expression appeared very low. Between 2 and 7 days postinjury, a time interval previously shown to correspond with smooth muscle cell migration followed by the appearance of a neointima, PDGF α receptor expression had increased only slightly, to roughly 35% above control levels, and was maximal by day 7 postinjury, whereas PDGF β receptor expression had doubled. From 7 to 14 days after carotid injury, intimal area was greatly increased and was associated with a further increase in PDGF β receptor protein expression and receptor phosphorylation to a maximum between days 10 and 12. In contrast, PDGF α receptor expression had decreased slightly during this time interval. Moreover, phosphorylation of PDGF α receptors was barely detectable and did not change over the time course of injury. From 14 to 28 days after injury, intimal area was increased only slightly, whereas PDGF β receptor protein and phosphorylation levels had diminished to roughly half of the 10-day injury values. In addition, the increases in PDGF β receptor protein expression and tyrosine phosphorylation observed over the time of injury were also associated with a corresponding increase in the association of phosphatidylinositol 3′ kinase (PI-3 kinase) with phosphorylated PDGF β receptors. These findings show that balloon injury to rat carotid arteries results in temporally related changes in the expression of PDGF receptors and their state of tyrosine phosphorylation. Furthermore, tyrosine phosphorylation of PDGF β receptors in the balloon-injured rat carotid artery in vivo resulted in the association of PI-3 kinase. These are important new findings, which add to our knowledge concerning the role and activity of PDGF receptors in the formation of a neointima.
Effect of Probucol Treatment on Gene Expression of VCAM-1, MCP-1, and M-CSF in the Aortic Wall of LDL Receptor–Deficient Rabbits During Early Atherogenesis
Authors: Fruebis Joachim , Gonzalez Virginia , Silvestre Mercedes , Palinski Wulf
Published: June 2011

Abstract
Probucol is a potent inhibitor of atherosclerosis in animal models. However, the mechanism of its antiatherogenic effect is not known. To investigate the effects of probucol on gene expression of VCAM-1, MCP-1, and M-CSF in vivo during the early stages of atherogenesis, we determined gene expression in 12 control WHHL rabbits and 12 WHHL rabbits fed 1% probucol from age 3 weeks. Three animals from each group were killed at 6, 9, 12, and 18 weeks of age. Two intimal/medial segments of the thoracic aorta, each comprising the orifices of a pair of intercostal arteries, were analyzed by semiquantitative RT-PCR using GAPDH as an internal standard. A third segment located between these two segments was studied by immunocytochemistry. A basal level of VCAM-1 gene expression was observed in lesion-free aortas of both treated and untreated WHHL rabbits (and in normal NZW aortas). Immunocytochemistry showed some VCAM-1 protein in normal arteries and confirmed that VCAM-1 protein expression generally correlated with gene expression. In the untreated WHHL rabbits, a marked upregulation of VCAM-1 expression was observed at 18 weeks. To correlate gene expression with intimal monocyte/macrophages in each animal, the macrophage area was determined by morphometry of immunostained sections. In addition, a scoring system of lesions was used. VCAM-1 expression showed a highly significant correlation with the extent of intimal macrophage presence (
P
<.001). A lesser degree of correlation between gene expression and macrophage accumulation was also seen for MCP-1. In contrast, M-CSF expression remained constant over the entire study period and showed no correlation with the intimal macrophage accumulation. Probucol treatment completely prevented lesion formation in all animals up to 18 weeks of age. Probucol reduced the level of basal VCAM-1 expression and prevented its upregulation. MCP-1 expression was not affected by probucol treatment, whereas M-CSF expression was significantly lowered by probucol. Our results support the idea that VCAM-1 plays an important role in early atherogenesis and suggest that the antiatherogenic effect of probucol may in part be due to a downregulation of VCAM-1. Reduction of the basal level of M-CSF gene expression by probucol treatment may also contribute to its ability to inhibit atherogenesis.
Lipoprotein Kinetics in Patients With Analbuminemia
Authors: Maugeais C. , Braschi S. , Ouguerram K. , Maugeais P. , Mahot P. , Jacotot B. , Darmaun D. , Magot T. , Krempf M.
Published: June 2011

Abstract
In vitro data suggested that albumin is a key factor controlling apolipoprotein (apo) synthesis by hepatocytes. Studies in analbuminemic rats have shown an increase in secretion of apoB-containing lipoprotein from the liver. We studied the kinetic aspects of apoB- and apoAI-containing lipoprotein metabolism in two sisters with analbuminemia using a constant 14-hour infusion of leucine labeled with stable isotopes. Compared with control subjects, total cholesterol was higher in the two patients (432 and 461 versus 155±14 mg/dL), as was apoB (257 and 230 versus 72±7 mg/dL). Triglycerides were slightly increased (134 and 105 versus 89±9 mg/dL), whereas apoAI was lower (109 and 105 versus 124±6 mg/dL). VLDL–apoB production was higher, as was the production of IDL–apoB and LDL–apoB (32.8 and 36.0 versus 24.8±5.9, 32.1 and 27.2 versus 16.4±2.3, and 14.1 and 17.6 versus 10.3±1.2 mg · kg
−1
· d
−1
, respectively). The fractional catabolic rate of all the apoB-containing lipoproteins was decreased (0.23 and 0.37 versus 0.48±0.05, 0.27 and 0.28 versus 0.62±0.08, and 0.012 and 0.009 versus 0.022±0.002 · h
−1
, respectively). A similar mechanism could explain the dyslipidemia observed in other conditions associated with low albumin levels, such as nephrotic syndrome.
Molecular Basis of Fish-Eye Disease in a Patient From Spain
Authors: Blanco-Vaca Francisco , Qu Shi-Jing , Fiol Concha , Fan Hui-Zhen , Pao Quein , Marzal-Casacuberta Àfrica , Albers John J. , Hurtado Isabel , Gracia Vicente , Pintó Xavier , Martí Tomás , Pownall Henry J.
Published: June 2011

AbstractThe genetic and biochemical basis of fish-eye disease (FED) was investigated in a 63-year-old female proband with low plasma HDL cholesterol. Analyses of corneal and plasma lipids of the proband were consistent with impaired lecithin:cholesterol acyltransferase (LCAT) activity. Free cholesterol and phospholipid levels were elevated relative to control values, whereas cholesteryl ester levels were greatly reduced. Fatty acid compositions of corneal lipids from the proband and control subjects differ from the respective fatty acid compositions of their plasma lipids. This suggests that the metabolic pathways and acyl chain specificities for phospholipid, cholesteryl ester, and triglyceride metabolism within the cornea are distinct from those of plasma. Sequencing of the LCAT gene from the proband revealed a novel mutation at nucleotide 399, corresponding to an Arg99→Cys substitution. Secretion of LCAT (Arg99→Cys) by transfected COS-6 cells was ≈50% of that of the wild type, but its specific activity against reassembled HDL was 93% lower than that of wild-type LCAT. The specific activities of wild-type and LCAT (Arg99→Cys) against LDL were reduced similarly, suggesting that the appearance of the FED phenotype does not require enhanced activity against LDL. Our data support the hypothesis that FED is a partial LCAT deficiency in which poor esterification in specific types of HDL particles may contribute to the appearance of the corneal opacities.
Uptake of Chylomicrons by the Liver, but Not by the Bone Marrow, Is Modulated by Lipoprotein Lipase Activity
Authors: Hussain M. Mahmood , Goldberg Ira J. , Weisgraber Karl H. , Mahley Robert W. , Innerarity Thomas L.
Published: June 2011

AbstractWe have shown that chylomicrons are catabolized by the liver and bone marrow in rabbits and marmosets. In the present investigation, we studied the role of various apolipoproteins and lipoprotein lipase in the clearance of these particles by the liver and bone marrow in rabbits. Incubation of chylomicrons with purified apolipoprotein (apo) E or C-II resulted in more rapid clearance of these particles from the plasma, whereas incubation of chylomicrons with apoA-I, apoC-I, apoC-III1, or apoC-III2did not affect their clearance rates. Analysis of tissue uptake revealed that the increased plasma clearance rate of chylomicrons enriched with apoE or apoC-II was primarily due to enhanced uptake by the liver. The uptake of chylomicrons by the bone marrow increased after their enrichment with apoA-I but decreased after their enrichment with apoC-II. Because apoC-II is a cofactor for lipoprotein lipase, we hypothesized that the increased clearance rates were due to faster hydrolysis of chylomicrons and rapid generation of chylomicron remnants. To test this hypothesis, lipoprotein lipase activity was inhibited by injection of an anti–lipoprotein lipase monoclonal antibody. Inhibition of lipoprotein lipase retarded clearance of chylomicrons from the plasma and decreased their uptake by the liver but did not affect their uptake by the bone marrow. These studies suggest that bone marrow can take up chylomicrons in the absence of lipoprotein lipase activity and provide an explanation for the presence of foam cells in the bone marrow of type I hyperlipoproteinemic patients.
Monocyte Chemotactic Protein-1 Expression Is Associated With the Development of Vein Graft Intimal Hyperplasia
Authors: Stark V.K. , Hoch J.R. , Warner T.F. , Hullett D.A.
Published: June 2011

AbstractInfiltration of immunologically active cells into vein grafts is concomitant with the development of intimal hyperplasia (IH) and often leads to obliterative stenosis and graft failure. Previous work has demonstrated the prolonged presence of monocytes and macrophages in vein grafts. The stimuli attracting these macrophages remain unidentified. Monocyte chemotactic protein-1 (MCP-1), a potent and specific chemokine for monocytes/macrophages, is secreted by smooth muscle cells, endothelial cells, fibroblasts, and leukocytes, all of which are present in grafted veins. In this study, we examined the temporal profile of MCP-1 gene expression in rat vein grafts by using reverse transcription–polymerase chain reaction (PCR) and immunohistochemistry. Epigastric vein–to–femoral artery bypass grafts were microsurgically placed and harvested at various time points after grafting. Histological analysis confirmed the consistent development of IH. PCR was performed and relative levels of MCP-1 quantified by autoradiography. Our results show that MCP-1 mRNA levels increased 28-fold by 4 hours after grafting and up to 117-fold by 1 week. After this time MCP-1 mRNA levels decreased; nonetheless, even at 8 weeks after grafting, message levels remained elevated 7-fold above baseline. Immunoreactive MCP-1 protein and ED1+ macrophages were detected at all time points; the degree of immunostaining correlated with MCP-1 mRNA levels. Our results support the hypothesis that upregulation of MCP-1 gene expression in vein grafts results in the recruitment of monocytes and tissue macrophages to the vein wall, which leads to IH. The correlation between monocyte/macrophage infiltration and IH suggests a critical role for these cells in IH development.
Bacterial Toxins Block Endothelial Wound Repair
Authors: Aepfelbacher Martin , Essler Markus , Huber Elisabeth , Sugai Motoyuki , Weber Peter C.
Published: June 2011

AbstractWe investigated the effect of bacterial toxins that modify and inactivate Rho GTP-binding proteins on the migratory response of endothelial cells to wounding. C3-transferase fromClostridium botulinum, EDIN fromStaphylococcus aureus, and toxin A fromClostridium difficileblocked migration of human umbilical vein endothelial cells (HUVECs) in an in vitro wound repair assay. Migrating HUVECs expressed actin microspikes (maximum at 10 minutes after wounding), ruffles (maximum at 12 hours), and fibers (maximum at 24 hours), and within these actin structures, vinculin-containing focal complexes/adhesions were formed. C3-Transferase ADP ribosylated RhoA, RhoB, and RhoC in HUVECs and abolished the formation of actin stress fibers/focal adhesions but had no effect on expression of microspikes, ruffles, or the associated vinculin-containing focal complexes. Similar results were obtained with EDIN and toxin A. These results indicate that endothelial cells migrating into a wounded area express distinct combinations of actin/vinculin structures in a spatially and temporally coordinated manner. The GTPase Rho selectively controls the formation of actin fibers/focal adhesions that occurs 2 to 24 hours after wounding. A mechanism is proposed by which Rho-specific bacterial toxins could influence vascular repair, angiogenesis, or atherosclerosis.
High Density Lipoproteins Stimulate Mitogen-Activated Protein Kinases in Human Skin Fibroblasts
Authors: Deeg Mark A. , Bowen Rosario F. , Oram John F. , Bierman Edwin L.
Published: June 2011

Abstract
Protein kinase C (PKC) seems to play an important role in many of HDL effects on cells, including removal of excess cholesterol. HDL removes cholesterol by at least two mechanisms. One mechanism involves desorption/diffusion of cholesterol from the plasma membrane onto the acceptor particle, whereas the second is mediated by apolipoproteins and may involve intracellular translocation of cholesterol to the plasma membrane for subsequent efflux. In this report, we examined the possibility that mitogen-activated protein (MAP) kinase is one of the downstream events from HDL activation of PKC. Using a gel kinase assay with myelin basic protein incorporated into the gel, HDL (50 μg protein/mL) stimulated multiple kinases of 42, 50, 52, 58, and 60 kDa. The 42-kDa protein kinase, corresponding to the unresolved MAP kinases ERK1 and ERK2 based on immunoblotting, was activated over 2-fold by HDL. HDL activated all identified kinases in a concentration- and time-dependent manner, which became maximal within 5 to 10 minutes and remained activated for at least 60 minutes. HDL activation of MAP kinase seems to be partially mediated by PKC, because down-regulation of PKC and known PKC inhibitors inhibited the HDL effect by 40 to 50%. Free apolipoproteins A-I (10 μg/mL) and A-II (10 μg/mL) had no significant effect on MAP kinase activation. Moreover, modifying HDL with trypsin or tetranitromethane, which abolishes apolipoprotein-mediated cholesterol efflux, had no effect on HDL activation of MAP kinase. These results suggest that HDL activates MAP kinase via multiple signal transduction pathways that are likely involved in an HDL effect unrelated to apolipoprotein-mediated cholesterol translocation and efflux.
Lipid Transfer Inhibitor Protein Activity Deficiency in Normolipidemic Uremic Patients on Continuous Ambulatory Peritoneal Dialysis
Authors: Serdyuk Anatole P. , Morton Richard E.
Published: June 2011

Abstract
We previously demonstrated that lipid transfer inhibitor protein (LTIP) is a potent modifier of lipid transfer protein (LTP) function in vitro. Based on these studies, we proposed that LTIP activity is an important determinant of lipoprotein size and composition, which leads to a stimulation of reverse cholesterol transport. To further evaluate this hypothesis, we have studied a normolipidemic, uremic patient population undergoing continuous ambulatory peritoneal dialysis (CAPD) that is deficient in LTIP activity (<18% of control). LDL from CAPD plasma was triglyceride enriched; the diameters of both CAPD LDL and HDL were increased and CAPD HDL was dominated by the largest subfraction, HDL
2b
. In CAPD patients, the plasma cholesterol esterification rate was only 61% of control; this decrease was due mainly to the poor reactivity of CAPD lipoproteins. CAPD lipoprotein-deficient plasma promoted twofold greater transfer of radiolabeled cholesteryl ester (CE) between standard lipoproteins than control, although LTP itself was increased only 39%. This twofold increase was not equally expressed among individual lipoprotein classes; CE transfers involving LDL were increased 2.4-fold, whereas those not involving LDL were increased only 50%. In whole plasma, CE net mass transfer to VLDL was slightly increased in CAPD plasma; relative to their CE content, control HDL contributed twofold more CE mass to VLDL than control LDL, but in CAPD plasma this preferential transfer of CE from HDL was absent. Collectively, the aberrations in CAPD lipoprotein composition and metabolism are consistent with the hypothesized role of LTIP. The data further support the role of LTIP in modulating the participation of HDL in CE mass transfers to VLDL. This is the first report of LTIP activity deficiency in humans.
Decreased Reverse Cholesterol Transport from Tangier Disease Fibroblasts
Authors: Remaley A.T. , Schumacher U.K. , Stonik J.A. , Farsi B.D. , Nazih H. , Brewer H.B.
Published: June 2011

Abstract
Tangier disease is characterized by HDL hypercatabolism and increased deposition of cholesterol in tissues. Tangier disease skin fibroblasts have decreased apoA-I-mediated cholesterol and phospholipid efflux, which may lead to the excess accumulation of cellular cholesterol. The mechanism of apolipoprotein-mediated cholesterol efflux and the apolipoprotein acceptor specificity for cholesterol efflux from normal and Tangier disease fibroblasts was investigated. Normal cells readily effluxed cholesterol and phospholipid to apoA-I and to all of the other apolipoproteins tested (apoA-II, AIV, C-I, C-II, C-III). In contrast, Tangier cells were almost completely defective in cholesterol efflux to apoA-I and to all of the other apolipoproteins tested. HDL was also less effective, by approximately 50%, in stimulating cholesterol efflux from Tangier cells compared with normal cells. In addition, Tangier cells also showed significantly reduced phospholipid efflux to both apolipoproteins and HDL. A similar rate of cholesterol efflux, however, was observed from normal and Tangier cells when phospholipid vesicles or cyclodextrin were used as acceptors. In contrast to normal cells, only phospholipid vesicles and cyclodextrin and not apoA-I or HDL depleted intracellular cholesteryl esters from Tangier cells. Brefeldin, an inhibitor of intracellular vesicular trafficking, decreased HDL-mediated cholesterol efflux by approximately 40% but almost completely blocked both cholesterol and phospholipid efflux to apoA-I from normal cells. Brefeldin also inhibited cholesteryl ester depletion by apoA-I and HDL from normal cells. Brefeldin, however, had no significant effect on cholesterol efflux from Tangier cells to HDL. In summary, Tangier cells were found to be defective in both cholesterol and phospholipid efflux to HDL and apoA-I. The defect in apolipoprotein-mediated lipid efflux was not specific for apoA-I but also occurred for other apolipoproteins, and brefeldin blocked HDL-mediated lipid efflux from normal but not Tangier disease cells. On the basis of these results, a model is proposed whereby decreased cholesterol efflux by apolipoproteins in Tangier cells is the result of a defect in a brefeldin-sensitive pathway of lipid efflux. (

Arterioscler Thromb Vasc Biol

. 1997;17:1813-1821.)
Hormonal Regulation of Lipoprotein(a) Levels: Effects of Estrogen Replacement Therapy on Lipoprotein(a) and Acute Phase Reactants in Postmenopausal Women
Authors: Tuck Catherine H. , Holleran Stephen , Berglund Lars
Published: June 2011

Abstract
Estrogen lowers lipoprotein(a) [Lp(a)] levels, but the mechanisms involved have not been clarified. To address the relationship between estrogenic effects on Lp(a) and serum lipids, and on other plasma proteins of hepatic origin, 15 healthy postmenopausal women participated in a randomized, double-blinded, placebo-controlled, crossover study with 4 weeks of oral conjugated estrogens (0.625 mg/d) and placebo, separated by a 6-week period. Lp(a) levels decreased during estrogen treatment in 14 of the 15 subjects (mean decrease, 23%;
P
<.001). In response to estrogen, apolipoprotein A-I (apoA-I), HDL cholesterol, and triglyceride levels increased by 12% (
P
=.001), 11% (
P
<.001), and 10% (
P
=.02), respectively. Apolipoprotein B (apoB) and LDL cholesterol levels decreased by 7% (
P
=.01) and 12% (
P
=.03), respectively. ApoB, LDL cholesterol, and Lp(a) levels fell within 1 week of treatment, whereas apoA-I and HDL cholesterol levels rose more slowly. Levels of acid α
1
-glycoprotein (AAG) and haptoglobin (HPT), two hepatically derived acute phase proteins, also decreased during estrogen treatment by 18% (
P
<.001) and 25% (
P
=.002), respectively. Although the changes in AAG and HPT in response to estrogen were highly correlated (
r
=.67,
P
=.009), we were unable to detect a correlation between change in either acute phase protein and change in Lp(a) (
r
=−.14 and −.24,
P
=.64 and .41). The lack of correlation between the changes in two acute phase reactants and Lp(a) suggests different underlying mechanisms for the effects of estrogen on these liver-derived proteins.
Signal Transduction Through Trimeric G Proteins in Megakaryoblastic Cell Lines
Authors: van der Vuurst Hans , van Willigen Gijsbert , van Spronsen Anke , Hendriks Maaike , Donath José , Akkerman Jan-Willem N.
Published: June 2011

AbstractThe biogenesis of trimeric G proteins was investigated by measurement of the expression of α-subunits in the megakaryoblastic cell lines MEG-01, DAMI, and CHRF-288-11, representing stages of increasing maturation, and compared with platelets. Megakaryoblasts and platelets contained approximately equal amounts of Giα-1/2, Giα-3, Gqα, and G12α protein. Maturation was accompanied by (1) downregulation of mRNA for Gsα and disappearance of iloprost-induced Ca2+mobilization, (2) upregulation of the long form of Gsα protein (Gsα-L) and an increase in iloprost-induced cAMP formation, and (3) upregulation of G16α mRNA and G16α protein and appearance of thromboxane A2-induced signaling (Ca2+mobilization and stimulation of prostaglandin I2–induced cAMP formation). Gzα protein was absent in the megakaryoblasts despite weak expression of Gzα mRNA in DAMI and relatively high levels of Gzα mRNA and Gzα protein in platelets. These findings reveal major changes in G protein–mediated signal transduction during megakaryocytopoiesis and indicate that G16α couples the thromboxane receptor to phospholipase Cβ.