bluuebunny/crossref_metadata_2025 huggingface dataset:
Low density lipoprotein metabolism in cultured fibroblasts from a new group of patients presenting clinically with homozygous familial hypercholesterolemia.
Authors: Coetzee G A , van der Westhuyzen D R , Berger G M , Henderson H E , Gevers W
Published: June 2011

The metabolism of low density lipoproteins (LDL) was studied in cultured fibroblasts obtained from five local patients diagnosed, on the basis of clinical features and serum cholesterol concentrations, as having the homozygous form of familial hypercholesterolemia. LDL receptor function was assessed by measuring the binding, internalization, and degradation of 125I-labeled LDL, and by measuring the stimulation of cellular acyl-CoA cholesterol acyltransferase (ACAT) activity which followed exposure to LDL. Fibroblasts from two cases (CF and GM) showed receptor activities which were approximately 10% of the values obtained with normal cells, while ACAT stimulation by LDL was very low. These two patients were classified as homozygous for a receptor-defective abnormality. However, fibroblasts from the other three patients (JG, ES, and TT) showed greater than 25% of normal receptor activity, as assessed by 125I-LDL binding and catabolism. ACAT stimulation by LDL in cells from JG and ES was within the range of values shown by cells previously characterized as heterozygous for a receptor-negative mutation. Cells from ES behaved atypically: a low, but nonsaturable, activation by LDL was evident. ACAT stimulation by LDL was normal in cells from TT. Receptor activities of the cells from the available parents, assessed on the basis of LDL binding and degradation or of ACAT stimulation, were not clearly distinguishable from those of normal cells. These results add to the growing evidence of genetic heterogeneity underlying the clinical picture associated with familial hypercholesterolemia in different geographical distributions.
Genetic susceptibility and resistance to diet-induced atherosclerosis and hyperlipoproteinemia.
Authors: Morrisett J D , Kim H S , Patsch J R , Datta S K , Trentin J J
Published: June 2011

To test the hypothesis that genetic susceptibility or resistance to diet-induced atherosclerosis is correlated with serum levels of specific lipids, lipoproteins, or apoproteins, male mice of a genetically susceptible and a genetically resistant strain were fed either a normal or an atherogenic diet. After 20 weeks on a normal diet, neither the resistant nor the susceptible strain mice had atherosclerosis; resistant strain mice had serum cholesterol of 66 +/- 11 while the susceptible strain mice had 90 +/- 1 mg/dl serum cholesterol, and lipoproteins were dominated by a single alpha-migrating HDL. After 20 weeks on an atherogenic diet, resistant strain mice had 185 +/- 55 mg/dl cholesterol, their lipoproteins remained dominated by alpha-migrating HDL, and two of eight mice had mild atherosclerotic lesions; susceptible strain mice had 510 +/- 94 mg/dl cholesterol, multiple alpha- and pre-beta-migrating lipoprotein species, and all 13 had advanced aortic atherosclerosis. The resistant strain mice had an apolipoprotein E/total lipoprotein protein ratio of 0.42 on the normal diet and 0.53 on the atherogenic diet, while the susceptible strain mice had the significantly lower ratios of 0.07 and 0.31, respectively. These data indicate that genetic resistance to diet-induced aortic atherosclerosis in mice is correlated with capacity to prevent large increases in serum cholesterol, to suppress abnormal alpha- and pre-beta-migrating lipoproteins, and to maintain elevated serum apolipoprotein E/total lipoprotein protein ratios. Our data do not preclude the possibility of additional gene control at the level of arterial end organ response.
Roles of lipoprotein lipase and hepatic triglyceride lipase in the catabolism in vivo of triglyceride-rich lipoproteins.
Authors: Reardon M F , Sakai H , Steiner G
Published: June 2011

To define the roles, in vivo, of hepatic triglyceride lipase and lipoprotein lipase in the catabolism of triglyceride-rich lipoproteins, we investigated the relationship between the activities of the above enzymes in postheparin plasma and the fractional removal rates of very low density lipoproteins (VLDL) and VLDL remnant particles. In 22 patients, the fractional removal rates of VLDL and VLDL-remnant particles were determined from analyses of the disappearance of radioiodinated Sf 60-400 and Sf 12-60 lipoprotein B apoprotein. The maximal activities of hepatic triglyceride lipase and lipoprotein lipase were determined in plasma samples drawn 2-60 minutes after heparin injection (60 U/kg). A positive correlation was observed between the fractional removal rate of VLDL and postheparin plasma lipoprotein lipase activity (r = 0.65). When all 22 patients were considered together, no relationship was demonstrable between remnant fractional removal and postheparin plasma lipoprotein lipase activity. However, humans may be subdivided with respect to the way in which they catabolize remnants. In some, all remnant may be catabolized to form LDL. In others, some of the remnant may also be directly removed from the circulation. Those subjects in whom previous studies indicate that all remnant is converted to LDL demonstrated a positive correlation between remnant fractional removal rate and postheparin plasma lipoprotein lipase activity (n = 8, r - 0.83). No correlations between postheparin plasma hepatic triglyceride lipase activity and any of the fractional removal rates were found. These data are consistent with the following: 1) lipoprotein lipase plays a key regulatory role in the catabolism of triglyceride-rich lipoproteins; 2) this role applies only to those catabolic involving the formation of particles of higher density VLDL remnants and low density lipoprotein; and 3) hepatic triglyceride lipase plays no rate-limiting role in the catabolism of VLDL or VLDL-remnant particles.
Platelet survival and thrombosis.
Authors: Winocour P D , Cattaneo M , Somers D , Richardson M , Kinlough-Rathbone R L , Mustard J F
Published: June 2011

This study examined the relation among platelet survival, thrombosis, and repeated vessel injury. With the use of 51Cr-labeled platelets, indwelling aortic catheters were shown to reduce platelet survival in rabbits and rats. In rabbits, thrombi were observed mainly at the aortic bifurcation and at the tip of the catheter. The amount of thrombus that formed in rabbits with short and long catheters was similar, but platelet survival was shortened only in rabbits with short and long catheters was similar, but platelet survival was shortened only in rabbits with long indwelling aortic catheters. In rats, the aortic catheters did not cause thrombosis, and platelet survival was shortened significantly in rats with both short and long catheters, but was more pronounced in animals with longer catheters. In both rabbits and rats, long aortic catheters caused more extensive vessel injury than the short catheters and this was associated with greater platelet interaction with the vessel wall. Platelet survival cannot be used as an estimate of thrombus formation, but may reflect the extent and frequency of vessel wall injury. thus, shortened platelet survival may represent increased platelet interaction with the damaged arterial wall and increased platelet consumption.
Concentration and composition of lipoproteins in blood plasma of the WHHL rabbit. An animal model of human familial hypercholesterolemia.
Authors: Havel R J , Kita T , Kotite L , Kane J P , Hamilton R L , Goldstein J L , Brown M S
Published: June 2011

Lipoproteins in blood plasma have been quantified and characterized in homozygous Watanabe-heritable hyperlipidemic (WHHL) rabbits, an animal model of human familial hypercholesterolemia. Like homozygous human hypercholesterolemics, WHHL rabbits have a severe deficiency of low density lipoprotein (LDL) receptors, a prolonged residence time for LDL, and an increased absolute rate of LDL catabolism. Although lipoproteins containing apolipoprotein B in WHHL rabbits are enriched in cholesteryl esters, their LDL as well as intermediate density lipoproteins (IDL) and very low density lipoproteins (VLDL) also contain a substantial amount of triglycerides and they consistently exhibit hypertriglyceridemia as well as hypercholesterolemia. The cholesteryl esters accumulating in lipoproteins of WHHL rabbits are rich in cholesteryl linoleate and appear to be produced almost exclusively by lecithin-cholesterol acyltransferase. Levels of apolipoprotein B-100 are elevated in VLDL and IDL as well as in LDL of WHHL rabbits and only trace amounts of apolipoprotein B-48 are present. Plasma levels of apolipoprotein E are also substantially increased, and VLDL and IDL are enriched in this protein. The accumulation of lipoproteins with the expected characteristics of remnants of hepatogenous triglyceride-rich lipoproteins contrasts with the efficient hepatic clearance of chylomicron remnants in WHHL rabbits.
Structural and functional changes of rhesus serum low density lipoproteins during cycles of diet-induced hypercholesterolemia.
Authors: Fless G M , Fischer-Dzoga K , Juhn D J , Bates S , Scanu A M
Published: June 2011

Over the course of a 2-year study, two male rhesus monkeys underwent episodes of diet-induced hypercholesterolemia (from a diet supplemented with 25% coconut oil and 2% cholesterol) followed by regression phases in which the animals received a low fat Purina chow diet. During the induction of hypercholesterolemia, serum cholesterol, apo B, saturation of low density lipoprotein (LDL) cholesteryl ester fatty acyl chains, and the ability of the serum to stimulate cholesterol esterification by smooth muscle cells rose immediately and in parallel, whereas there was a lag period before the serum became mitogenic to smooth muscle cells. Concurrently, there were important changes in the density, size, chemistry, and concentration of the LDL species in the rhesus serum; induced LDL shifted from the LDL-II to the LDL-I density region with increasing cholesterol concentration. Both structural and functional changes were reversed upon return to a normal Purina chow diet, although at different rates. Serum cholesterol, apo B, and the rate of cholesterol esterification in smooth muscle cells promoted by the serum declined in parallel while the mitogenicity of the serum to smooth muscle cells and the degree of saturation of LDL cholesteryl ester fatty acids took longer to return to normal values. In fact, there was an immediate and dramatic rise in saturation upon reversal before the LDL cholesteryl ester fatty acyl chains returned to their normal composition. The Lp(a) particles did not increase in either concentration or size in response to the test diet, although the change in their lipid composition was similar to those of the other LDL species. The studies indicate that dietary manipulations affect the physicochemical properties of the LDL particles, and that the resultant structural alterations are accompanied by changed in vitro cellular response, suggestive of a greater atherogenicity.
Comparison of cholesteryl ester transfer from chylomicrons and other plasma lipoproteins to aortic intima media of cholesterol-fed rabbits.
Authors: Stender S , Zilversmit D B
Published: June 2011

Lymph chylomicrons labeled with 14C-cholesterol and plasma very low and intermediate density lipoproteins (d less than 1.019) labeled with 3H-cholesterol were injected simultaneously into recipient cholesterol-fed rabbits. The cholesteryl ester of chylomicron origin (14C) found in the tissues 1 to 4 hours after the injection is the sum of both direct and indirect uptake of chylomicron cholesteryl ester. The direct uptake of chylomicron cholesteryl ester is defined as occurring in situ during the interaction between chylomicrons and lipoprotein lipase in endothelial cells. The indirect uptake of chylomicron cholesteryl ester results from the uptake of chylomicron remnants and of other plasma lipoproteins which become labeled during the degradation of the injected chylomicrons by net lipid transfer or by exchange. The indirect contribution of chylomicron cholesteryl ester to tissues was calculated from tissue 3H-cholesteryl ester derived from injected plasma d less than 1.019 lipoproteins. In rabbits fed 0.5 g cholesterol daily for 40-60 days, with plasma cholesterol concentrations between 20 and 30 mM (800-1200 mg/dl), less than 1% of the cholesteryl ester influx into aortic intima media and less than 10% in liver was derived from the direct uptake of chylomicron cholesteryl ester.
Correlates of low density lipoprotein cholesterol: associations with physical, chemical, dietary, and behavioral characteristics.
Authors: Schwarz W , Trost D C , Reiland S L , Rifkind B M , Heiss G
Published: June 2011

The purpose of this cross-sectional study was to describe the relationship between low density lipoprotein cholesterol (LDL-C) and various physical, chemical, dietary, and behavioral attributes of 4768 white men and women aged 20-59 years from 10 North American populations sampled by the Lipid Research Clinics Program. For our analyses, women were separated into two groups: users and nonusers of hormones. A positive correlation coefficient between very low density lipoprotein cholesterol (VLDL-C) and LDL-C was observed for women but not for men. Fasting plasma concentrations of LDL-C were most strongly and consistently associated in each gender with age, the Quetelet Index of body mass, the number of cigarettes smoked per day, systolic blood pressure, and the levels of plasma glucose and uric acid (all positive associations); and with height and bilirubin levels (both negative associations). Gender-related differences were found in the associations between LDL-C and the other lipids and lipoprotein cholesterol fractions measured. The associations between LDL-C and individual nutrients computed from a 24-hour dietary recall were generally of a low-order magnitude. The strongest and most consistent among the statistically significant associations were those between LDL-C and total caloric intake and with carbohydrates and sucrose (all negative associations). Other statistically significant association between LDL-C and reported intake of nutrients were less consistent, e.g., LDL-C levels were negatively related to alcohol consumption in women, but showed a weak positive relation to alcohol intake in men. Multiple linear stepwise regression was used to assess the variation in LDL-C concentration attributable to each characteristic under study, adjusted for concomitant variation in any other variable. As in the univariable analyses, age was the strongest covariate of LDL-C; adjusting for all other terms in the stepwise regression analysis, cigarette smoking was identified as the next strongest determinant of LDL-C. Other measurements, such as body mass, clinical chemistries, and alcohol consumption, emerged as independent predictors of LDL-C levels in a pattern specific to gender and to hormone use.
Relationships of nutrient intake to lipids and lipoproteins in 1234 white children. The Lipid Research Clinics Prevalence Study.
Authors: Glueck C J , Waldman G , McClish D K , Morrison J A , Khoury P , Larsen R , Salz K , Rifkind B M , Mattson F H
Published: June 2011

Using the geographically and socioeconomically varied collaborative Lipid Research Clinics Prevalence Study data, this report focuses upon relationships between dietary intake and plasma lipids and lipoproteins in 1234 white children, 661 boys and 573 girls, aged 6-19 years who were sampled in a random recall (Visit 2) from large populations in six Lipid Research Clinics. Using multiple regression analysis, we found that in 6- to 12-year-old boys the dietary polyunsaturated-to-saturated fat ratio was inversely associated with plasma total and low density lipoprotein cholesterol and dietary cholesterol was positively associated with plasma high density lipoprotein cholesterol. In 13- to 19-year-old boys, high density lipoprotein cholesterol and the ratio of high density lipoprotein cholesterol to total cholesterol were inversely related to sucrose intake. In 6- to 12-year-old girls, plasma triglycerides were positively related to dietary sucrose. Using analysis of covariance in children having the lowest, middle, and top decile nutrient intakes, we found that higher carbohydrate intakes were associated with lower plasma total cholesterol in boys. The highest polyunsaturated fat intake (in 6- to 12-year-old girls) was associated with the lowest plasma cholesterol and very low density lipoprotein cholesterol. The highest cholesterol intake (in 6- to 12-year-old boys) was associated with the highest high density lipoprotein cholesterol levels. In girls, the highest sucrose intakes were associated with the highest plasma triglyceride levels. We conclude that the weak, but statistically significant, associations that we observed were meaningful relative to etiologies of nutrient-lipoprotein interrelationships, and should be useful in forming new hypotheses for focused metabolic ward studies.
Induction of Ubiquitin-Conjugating Enzyme by Aggregated Low Density Lipoprotein in Human Macrophages and Its Implications for Atherosclerosis
Authors: Kikuchi Jiro , Furukawa Yusuke , Kubo Nobuhiko , Tokura Akihiko , Hayashi Nakanobu , Nakamura Mitsuru , Matsuda Michio , Sakurabayashi Ikunosuke
Published: June 2011

Abstract
—Recently, we have found that aggregated low density lipoprotein (agLDL) inhibits apoptosis of lipid-bearing macrophages, thereby facilitating foam cell formation and atherosclerosis. To clarify the mechanisms by which agLDL inhibits apoptosis of macrophages, we isolated the genes specifically induced by agLDL by using a subtraction-based cloning strategy. One of the cloned genes, termed low density lipoprotein (LDL)-inducible gene (
LIG
), encodes a human homologue of bovine ubiquitin-conjugating enzyme E2–25K. Although
LIG
mRNA was ubiquitously expressed among human tissues, including hematopoietic cells, the abundance of transcripts was markedly increased by agLDL treatment in activated monocytes.
LIG
mRNA expression was not enhanced by nonatherogenic lipoproteins such as native LDL and high density lipoprotein, suggesting a role in atherosclerosis. Polyubiquitination of intracellular proteins was observed in monocytes cultured with agLDL, which coincided with upregulation of
LIG
. Furthermore, ubiquitin-dependent degradation of p53, an inducer of apoptosis, was accompanied by
LIG
induction in agLDL-treated monocytes. The antiapoptotic effect of agLDL was abrogated by a specific proteasome inhibitor, which also increased the half-life of p53 in monocytes. These results suggest that LIG contributes to foam cell formation by the suppression of apoptosis of lipid-bearing macrophages through ubiquitination and subsequent degradation of p53.
Identification of Quantitative Trait Loci for Serum Cholesterol Levels in Stroke-Prone Spontaneously Hypertensive Rats
Authors: Kato Norihiro , Tamada Tomoko , Nabika Toru , Ueno Keita , Gotoda Takanari , Matsumoto Chiho , Mashimo Tomoji , Sawamura Makoto , Ikeda Katsumi , Nara Yasuo , Yamori Yukio
Published: June 2011

Abstract
—The stroke-prone spontaneously hypertensive rat (SHRSP) has been reported to show significantly lower levels of serum total cholesterol than the normotensive control strain Wistar-Kyoto rat (WKY). Because selective inbreeding was conducted for stroke proneness, this concomitantly inherited characteristic of SHRSP may play some pathophysiological role in stroke. We evaluated the genetic determinants of the cholesterol trait by estimating heritability and subsequently by undertaking a genome-wide screen with 161 genetic markers in F
2
progeny involving SHRSP and WKY (104 male and 106 female rats). Three quantitative trait loci (QTLs) were detected on rat chromosomes 5, 7, and 15. Markers from the linked region on chromosome 15 indicated significant evidence of linkage with a maximal log of the odds (LOD) score of 7.7, whereas those on chromosomes 5 and 7 cosegregated with the trait in a sex-specific manner (the QTL close to genetic marker
D5 Mit5
reached an LOD score of 7.3 in males, and that close to
D7 Mit10
reached an LOD score of 3.2 in females). The male-specific QTL on chromosome 5 appeared to overlap with previously reported QTLs for stroke-associated phenotypes, but an identical gene (or genes) appeared unlikely to control these and the cholesterol traits simultaneously. In the present study, serum cholesterol levels were shown to be highly genetically determined in SHRSP (the heritability estimates are 76% in males and 83% in females), and 3 QTLs with substantial effects were identified. Further work, however, is required to clarify whether the cholesterol trait is related to the etiology of stroke or has been retained by chance through the inbreeding process in SHRSP.
Pressure-Induced Upregulation of Preproendothelin-1 and Endothelin B Receptor Expression in Rabbit Jugular Vein In Situ
Authors: Lauth Manfred , Berger Marc-Moritz , Cattaruzza Marco , Hecker Markus
Published: June 2011

Abstract—Upregulation of endothelin-1 (ET-1) synthesis in venous bypass grafts in response to arterial levels of blood pressure may play a major role in graft failure. To investigate this hypothesis, isolated segments of the rabbit jugular vein were perfused at physiological (0 to 5 mm Hg) and nonphysiological (20 mm Hg) levels of intraluminal pressure. As judged by reverse transcription–polymerase chain reaction analysis (mRNA level), neither endothelin-converting enzyme nor endothelin A receptor expression appeared to be pressure sensitive. In contrast, there was a profound and time-dependent increase in endothelial prepro-ET-1 mRNA and intravascular ET-1 abundance (by ELISA) as well as in smooth muscle endothelin B receptor mRNA and functional protein (by superfusion bioassay) on raising the perfusion pressure from 5 to 20 mm Hg, but not from 0 to 5 mm Hg, for up to 12 hours. Video microscopy analysis revealed that the segments were distended by 75% at 5 mm Hg and near maximally at 20 mm Hg compared with the resting diameter at 0 to 1 mm Hg. Treatment of the segments with actinomycin D (1 μmol/L), the specific protein kinase C inhibitor, Ro 31–8220 (0.1 μmol/L), or the c-Src family–specific tyrosine kinase inhibitor, herbimycin A (0.1 μmol/L), demonstrated that the pressure-induced expression of these gene products occurs at the level of transcription and requires activation of protein kinase C, but not c-Src. In venous bypass grafts such deformation-induced changes in gene expression may contribute not only to acute graft failure through ET-1–induced vasospasm but also to endothelin A receptor– and/or endothelin B receptor–mediated smooth muscle cell hyperplasia and graft occlusion.
c7E3Fab Reduces Postischemic Leukocyte-Thrombocyte Interaction Mediated by Fibrinogen
Authors: Kupatt Christian , Habazettl Helmut , Hanusch Peter , Wichels Reinhard , Hahnel Daniela , Becker Bernhard F. , Boekstegers Peter
Published: June 2011

Abstract—Reperfusion injury after coronary occlusion is in part mediated by leukocyte activation and adhesion. Platelets may interact with polymorphonuclear granulocytes (PMNs), causing aggravated reperfusion injury. We studied whether c7E3Fab, a chimeric Fab fragment blocking platelet glycoprotein (GP) IIb/IIIa, decreases PMN-platelet–dependent myocardial dysfunction after ischemia. Isolated guinea pig hearts (n=5 per group) perfused at a constant flow of 5 mL/min were subjected to ischemia (15 minutes, 37°C) and reperfusion. Human PMNs (10×106cells, 3 mL), platelets (400×106, 3 mL), and fibrinogen (1 mg/mL) were infused for 3 minutes after 2 minutes of reperfusion, with or without c7E3Fab. Flow cytometry detected GPIIb/IIIa (platelets) and MAC-1 (aMβ2, PMNs) as well as coaggregates of both in the effluent, whereas double-fluorescence microscopy visualized intracoronary PMN-platelet coaggregates. Postischemic recovery of pressure-volume work (12–cm H2O preload and 60–mm Hg afterload) was defined as the ratio of postischemic to preischemic external heart work (mean±SEM). c7E3Fab reduced platelet GPIIb/IIIa detection to 10% of controls, blocked a transcoronary MAC-1 increase (+25% without versus −23% with c7E3Fab), and inhibited PMN-platelet coaggregation in the effluent (49±12% without versus 17±2% with c7E3Fab) as well as in the hearts themselves (5.0±0.7/cm2without versus 1.2±0.3/cm2surface area with c7E3Fab). Postischemic recovery of external heart work (83±5% in cell-free hearts) declined to 46±4% after postischemic PMN-platelet infusion, but not in the presence of c7E3Fab (74±11%) or LPM19c (71±6%). We conclude that c7E3Fab inhibits formation of PMN-platelet aggregates during myocardial reperfusion, an effect that protects against PMN-platelet–dependent stunning.
Circulating Oxidized Low Density Lipoprotein Levels
Authors: Toshima Shun-ichi , Hasegawa Akira , Kurabayashi Masahiko , Itabe Hiroyuki , Takano Tatsuya , Sugano Jinpei , Shimamura Kyoko , Kimura Junji , Michishita Ichiro , Suzuki Toru , Nagai Ryozo
Published: June 2011

Abstract—Recent studies have established oxidative modification of low density lipoprotein (LDL) as an important atherogenic factor. We examined the clinical relevance of circulating oxidized LDL (OxLDL) levels in atherosclerotic disease by an enzyme immunoassay with use of specific antibodies against OxLDL (FOH1a/DLH3) and apolipoprotein B. Plasma OxLDL levels were significantly higher in patients with coronary heart disease (n=65) than in control subjects (n=181; 201.3±11.2 versus 112.4±3.3 U/dL, respectively;P<0.01). OxLDL levels were not associated with age, sex, total cholesterol, or apolipoprotein B levels in normal control subjects. Our results suggest that circulating OxLDL may be a possible biochemical risk marker for coronary heart disease.
Determinants of Bioactivity of Oxidized Phospholipids
Authors: Subbanagounder Ganesamoorthy , Leitinger Norbert , Schwenke Dawn C. , Wong Jason W. , Lee Hans , Rizza Christina , Watson Andrew D. , Faull Kym F. , Fogelman Alan M. , Berliner Judith A.
Published: June 2011

Abstract
—We previously described 3 bioactive oxidation products of 1-palmitoyl-2-arachidonoyl-
sn
-glycero-3-phosphorylcholine (PAPC) containing oxovaleroyl (POVPC), glutaroyl (PGPC), and epoxyisoprostane (PEIPC) groups at the
sn
-2 position that were increased in minimally modified/oxidized low density lipoprotein (MM-LDL) and rabbit atherosclerotic lesions. We demonstrated specific and contrasting effects of POVPC and PGPC on leukocyte-endothelial interactions and described an effect of PEIPC on monocyte binding. The major purpose of the present study was to determine the effects of structural changes on the bioactivities of these 3 lipids. We demonstrate herein that the group at the
sn
-2 position determines the specific bioactivity and that the substitution of stearoyl for palmitoyl at the
sn
-1 position or ethanolamine for choline at the
sn
-3 position of the phospholipid did not alter bioactivity. Oxidized PAPC, oxidized 1-stearoyl-2-arachidonoyl-
sn
-glycero-3-phosphorylcholine, and oxidized 1-stearoyl-2-arachidonoyl-
sn
-glycero-3-phosphorylethanolamine stimulated monocyte binding and inhibited lipopolysaccharide-induced expression of the neutrophil-binding molecule E-selectin. Furthermore, all oxovaleroyl phospholipids but not the glutaroyl phospholipids induced monocyte binding without an increase in vascular cell adhesion molecule-1 (VCAM-1) expression and inhibited lipopolysaccharide-induced E-selectin expression. In contrast, glutaroyl phospholipids but not oxovaleroyl phospholipids stimulated E-selectin and VCAM-1 expression. We further demonstrate that all parts of the phospholipid molecules are required for these bioactivities. Hydrolysis with phospholipase (PL) A
1
, PLA
2
, and PLC strongly reduced the bioactivities of POVPC, PGPC, and mixed isomers of PEIPC. PLD had a smaller but still significant effect. The effects of POVPC and PEIPC could be abolished by sodium borohydride treatment, indicating the importance of the reducible groups (carbonyl and epoxide) in these molecules. In summary, these studies identify 6 new bioactive, oxidized phospholipids that are increased in MM-LDL and, where measured, in atherosclerotic lesions. They thus suggest that a family of phospholipid oxidation products containing oxovaleroyl, glutaroyl, and epoxyisoprostane at the
sn
-2 position play an important role in the regulation of leukocyte-endothelial interactions, bioactivity being in part controlled by several types of phospholipid hydrolases.
Effect of Macrophage-Derived Apolipoprotein E on Established Atherosclerosis in Apolipoprotein E–Deficient Mice
Authors: Shi Weibin , Wang Xuping , Wang Nicholas J. , McBride William H. , Lusis Aldons J.
Published: June 2011

Abstract—Apolipoprotein E–deficient (apoE−/−) mice have hyperlipidemia and develop spontaneous atherosclerosis in a time-dependent manner. Although macrophage-derived apoE has been shown to prevent the development of atherosclerosis in apoE−/−mice, whether it would induce regression of established atherosclerosis is unknown. To determine this, 8-week-old apoE−/−mice were transplanted with apoE+/+bone marrow. Four weeks after transplantation, when plasma cholesterol levels had reached normal levels, a group of mice (n=12) were killed and their aortic lesions were measured and used as a baseline to judge regression. Twelve and 20 weeks after transplantation, aortic lesion areas of the mice were 9340±2184 μm2(mean±SEM, n=8) and 12 211±1433 μm2(n=9), respectively, values not significantly different from the lesion areas of the baseline mice (12 347±2487 μm2; n=12,P>0.05). In contrast, apoE−/−mice reconstituted with apoE−/−bone marrow developed severe atherosclerotic lesions (453 036±29 767 μm2, n=7) 20 weeks after transplantation. These data suggest that macrophage-derived apoE was insufficient to induce significant regression of established atherosclerotic lesions in apoE−/−mice, although it was sufficient to eliminate hypercholesterolemia and prevent progression of aortic lesions.
Effect of Overexpression of Human Apo A-I in C57BL/6 and C57BL/6 Apo E–Deficient Mice on 2 Lipoprotein-Associated Enzymes, Platelet-Activating Factor Acetylhydrolase and Paraoxonase
Authors: Bart De Geest  , Stengel Dominique , Landeloos Michèle , Lox Marleen , Le Gat Laurence , Collen Désiré , Holvoet Paul , Ninio Ewa
Published: June 2011

Abstract
—Various mechanisms may contribute to the antiatherogenic potential of apolipoprotein A-I (apo A-I) and high density lipoproteins (HDLs). Therefore, the effect of adenovirus-mediated human apo A-I gene transfer or human apo A-I transgenesis on platelet-activating factor acetylhydrolase (PAF-AH) and arylesterase/paraoxonase (PON1) was studied in C57BL/6 and C57BL/6 apo E
−/−
mice. Human apo A-I transgenesis in C57BL/6 mice resulted in a 4.2-fold (
P
<0.0001) increase of PAF-AH and a 1.7-fold (
P
=0.0012) increase of PON1 activity. The apo E deficiency was associated with a 1.6-fold (
P
=0.008) lower PAF-AH and a 2.0-fold (
P
=0.012) lower PON1 activity. Human apo A-I transgenesis in C57BL/6 apo E
−/−
mice increased PAF-AH and PON1 activity by 2.1-fold (
P
=0.01) and 2.5-fold (
P
=0.029), respectively. After adenovirus-mediated gene transfer of human apo A-I into C57BL/6 apo E
−/−
mice, a strong correlation between human apo A-I plasma levels and PAF-AH activity was observed at day 6 (
r
=0.92,
P
<0.0001). However, PON1 activity failed to increase, probably as a result of cytokine-mediated inhibition of PON 1 expression. In conclusion, this study indicates that overexpression of human apo A-I increases HDL-associated PAF-AH activity. PON1 activity was also increased in human apo A-I transgenic mice, but not after human apo A-I gene transfer, a result that was probably related to cytokine production induced in the liver by the adenoviral vectors. Increased levels of these HDL-associated enzymes may contribute to the anti-inflammatory and antioxidative potential of HDL and thereby to the protection conferred by HDL against atherothrombosis.
Role of Lipids in Osteoporosis
Authors: Parhami Farhad , Garfinkel Alan , Demer Linda L.
Published: June 2011

Abstract
—Cardiovascular disease and osteoporosis together account for most of the morbidity and mortality in our aging population despite significant improvements in treatment. Recently, converging lines of evidence suggest that these 2 diseases share an etiologic factor –that hyperlipidemia contributes not only to atherosclerotic plaque formation, but also to osteoporosis, following a similar biologic mechanism involving lipid oxidation. In vitro studies indicate that lipid products of oxidation promote osteoblastic differentiation of vascular cells and inhibit such differentiation in bone cells. Ex vivo, in vivo, and clinical studies further suggest that lipid-lowering agents reduce both atherosclerotic calcification and osteoporosis. Whether lipid-lowering agents reduce osteoporosis directly or indirectly through lipid reduction remains controversial.
Rho-Kinase Is Involved in Macrophage-Mediated Formation of Coronary Vascular Lesions in Pigs In Vivo
Authors: Miyata Kenji , Shimokawa Hiroaki , Kandabashi Tadashi , Higo Taiki , Morishige Kunio , Eto Yasuhiro , Egashira Kensuke , Kaibuchi Kozo , Takeshita Akira
Published: June 2011

Abstract
—We have previously shown that long-term treatment with an inflammatory cytokine from the adventitia causes the development of coronary vascular lesions, with the accumulation of macrophages. Recent studies in vitro have suggested that small G-protein Rho and its effector, Rho-kinase/ROK/ROCK, may be the key molecules for various cellular functions, including cell adhesion and movement. In this study, we examined whether adventitia-derived macrophages cause the formation of coronary vascular lesions in vivo and, if so, whether Rho-kinase is involved in the process. Porcine coronary segments from the adventitia were chronically treated with monocyte chemoattractant protein-1 alone, oxidized low density lipoprotein alone, or both. Vascular lesion formation (neointimal formation and development of vascular remodeling) was mostly enhanced at the coronary segment cotreated with monocyte chemoattractant protein-1 and oxidized low density lipoprotein, where the phosphorylation of myosin binding subunit of myosin phosphatase was increased, indicating an increased activity of Rho-kinase in vivo. Histological examination demonstrated that macrophages were accumulated at the adventitia and thereafter migrated into the vascular wall. Long-term oral treatment with fasudil, which is metabolized to a specific Rho-kinase inhibitor (hydroxyfasudil) after oral absorption, markedly inhibited the myosin binding subunit phosphorylation, the macrophage accumulation and migration, and the coronary lesion formation in vivo. These results indicate that Rho-kinase is involved in macrophage-mediated formation of coronary vascular lesions in our porcine model in vivo.
Adenovirus-Mediated Human Tissue Kallikrein Gene Delivery Induces Angiogenesis in Normoperfused Skeletal Muscle
Authors: Emanueli Costanza , Zacheo Antonella , Minasi Alessandra , Chao Julie , Chao Lee , Salis Maria Bonaria , Stacca Tiziana , Straino Stefania , Capogrossi Maurizio C. , Madeddu Paolo
Published: June 2011

Abstract—We investigated whether local delivery of the tissue kallikrein gene induces angiogenesis in normoperfused mouse hindlimb muscles. Intramuscular injection of adenovirus containing the human tissue kallikrein gene under the control of a cytomegalovirus enhancer/promoter sequence resulted in local production and release of recombinant human tissue kallikrein, whereas transgene expression was absent in muscles of the contralateral hindlimb. Angiogenesis in infected muscles was documented by histological evidence of increased capillary density. In contrast, no angiogenic effect was seen either in the ipsilateral gastrocnemius or contralateral hindlimb muscles. Neovascularization was associated with a transient increase in muscular blood flow as determined by laser Doppler flowmetry. We also investigated the mechanisms of kallikrein-induced angiogenesis. We found that the angiogenic response to kallikrein was abolished by chronic blockade of the kinin B
1
or B
2
receptor or by inhibition of nitric oxide synthase. In addition, inhibition of cyclooxygenase-2 by nimesulide significantly reduced kallikrein-induced effects. These results indicate that (1) human tissue kallikrein acts as an angiogenic factor in normoperfused skeletal muscle and (2) nitric oxide and prostacyclin are essential mediators of kallikrein-induced angiogenesis. Our findings provide new insights into the role of the tissue kallikrein-kinin system in vascular biology.
Effect of Vitamin C on Forearm Blood Flow and Glucose Metabolism in Essential Hypertension
Authors: Natali Andrea , Sironi Anna Maria , Toschi Elena , Camastra Stefania , Sanna Giovanna , Perissinotto Armando , Taddei Stefano , Ferrannini Ele
Published: June 2011

Abstract
—In 9 patients with essential hypertension, we tested whether a high-dose (12 mg · min
−1
) vitamin C infusion into the brachial artery, by improving endothelium-dependent vasodilatation, would also attenuate the insulin resistance of deep forearm tissues. We measured the effect of vitamin C on acetylcholine (Ach)-induced vasodilatation and on forearm glucose uptake during systemic hyperinsulinemia; in all studies, the contralateral forearm served as the control. Intrabrachial Ach infusion produced a stable increase in forearm blood flow, from 2.6±0.3 to 10.6±2.1 mL · min
−1
· dL
−1
; when vitamin C was added, a further rise in forearm blood flow (to 13.4 mL · min
−1
· dL
−1
;
P
<0.03 vs Ach alone) was observed. In response to insulin, blood flow in both the infused and control forearms did not significantly change from baseline values (+10±16% and +2±11%, respectively). In contrast, when vitamin C was added, blood flow in the infused forearm increased significantly (to 3.7±0.7 mL · min
−1
· dL
−1
;
P
<0.02 vs 2.8±0.6 mL · min
−1
· dL
−1
in the control forearm). Insulin stimulated whole-body glucose disposal to 20±2 μmol · min
−1
· kg
−1
, compatible with the presence of marked insulin resistance. Forearm glucose uptake was similarly stimulated after 80 minutes of insulin infusion (to 2.11±0.42 and 2.06±0.43 μmol · min
−1
· dL
−1
, infused and control, respectively). When intrabrachial vitamin C was added, no difference in glucose uptake was observed between the 2 forearms (infused, 2.37±0.44 μmol · min
−1
· dL
−1
and control, 2.36±0.53 μmol · min
−1
· dL
−1
). Forearm O
2
uptake at baseline was also similar in the 2 forearms (infused, 9.7±0.7 μmol · min
−1
· dL
−1
and control, 9.6±1.1 μmol · min
−1
· dL
−1
) and was not changed by either insulin or vitamin C. We conclude that in the deep forearm tissues of patients with essential hypertension and insulin resistance, an acute improvement in endothelial function, obtained with pharmacological doses of vitamin C, restores insulin-mediated vasodilatation but does not improve insulin-mediated glucose uptake. Thus, the endothelial dysfunction of essential hypertension is unlikely to be responsible for their metabolic insulin resistance.
High Dose of Simvastatin Normalizes Postprandial Remnant-Like Particle Response in Patients With Heterozygous Familial Hypercholesterolemia
Authors: Twickler Th. B. , Dallinga-Thie G. M. , de Valk H. W. , Schreuder P. C. N. J. , Jansen H. , Cabezas M. Castro , Erkelens D. W.
Published: June 2011

Abstract
—Familial hypercholesterolemia (FH) and disturbances in postprandial lipoprotein metabolism are both associated with premature atherosclerosis. The effect of β-hydroxy-β-methylglutaryl coenzyme A reductase inhibitors on plasma cholesterol levels in patients with FH is well established; however, it is not known whether postprandial lipoproteins are also influenced. In this case-controlled intervention study, we investigated the effects of high-dose simvastatin on postprandial lipoproteins. We used a new method to analyze remnant lipoproteins based on the immunoseparation principle (remnant-like particle cholesterol [RLP-C] assay) and the well-established measurement of retinyl ester (RE) analysis in plasma and in the Svedberg flotation unit (Sf)<1000 fraction. Seven heterozygous FH patients and 7 control subjects matched for sex, age, body mass index, triglycerides, and apolipoprotein E genotype were enrolled in the study. An oral vitamin A (RE) fat-loading test was performed at baseline in both groups and after 3 months of high-dose simvastatin (80 mg/d) treatment in the FH patients. Before treatment, FH patients had significantly higher fasting and postprandial concentrations of lipoprotein remnants (plasma RLP-C 42±19 mg/dL and area under the RLP-C curve 415±82 mg · L
−1
· h
−1
, respectively) than did control subjects (7±3 mg/dL and 101±35 mg · L
−1
· h
−1
, respectively;
P
<0.05), suggesting a delayed clearance of chylomicron remnant particles in the FH patients. Treatment with simvastatin significantly reduced fasting and postprandial remnant lipoprotein cholesterol concentrations (13±3 mg/dL and 136±53 mg · L
−1
· h
−1
, respectively;
P
<0.05 for both). Postprandial RE in the Sf<1000 fraction, not total RE in plasma, was also significantly higher in FH patients than in control subjects (24±10 versus 6.3±5.9 mg · L
−1
· h
−1
,
P
<0.05), but treatment with simvastatin did not result in improvement of the postprandial RE response, either in the Sf<1000 fraction or in plasma. It is concluded that heterozygous FH patients have increased fasting and postprandial remnant lipoprotein concentrations. Treatment with simvastatin significantly reduced the fasting and postprandial RLP-C concentrations but did not result in improved postprandial RE response.
Decreased Susceptibility to Diet-Induced Atherosclerosis in Human Apolipoprotein A-II Transgenic Mice
Authors: Tailleux Anne , Bouly Muriel , Luc Gérald , Castro Graciela , Caillaud Jean-Michel , Hennuyer Nathalie , Poulain Philippe , Fruchart Jean-Charles , Duverger Nicolas , Fiévet Catherine
Published: June 2011

Abstract
—Studies performed in vivo have been controversial regarding the implication of human apolipoprotein (apo)A-II in the atherogenic process. Expression of human apoA-II in transgenic mice fed a chow diet leads to (1) a bimodal distribution of high density lipoprotein (HDL) size as in humans, (2) a reduction in total cholesterol concentration that is mainly due to a reduction in non–HDL cholesterol level, and (3) a dramatic reduction in mouse endogenous apoA-I and apoA-II. After 20 weeks on an atherogenic diet, transgenic mice had reduced total cholesterol concentrations because of a reduction in cholesterol associated with all lipoprotein classes. Endogenous apoA-I and apoA-II were also dramatically decreased in transgenic mice. The mean area of atherosclerotic lesions was drastically decreased in transgenic mice (−44%,
P
=0.0027) compared with control mice. The amount of aortic surface covered by lesions was positively correlated with very low density lipoprotein cholesterol (
P
<0.01) and intermediate density lipoprotein cholesterol levels (
P
<0.05). Transgenic mice were protected against the development of atherosclerosis despite a marked decrease in HDL cholesterol and apoA-I concentrations. This protection may be related to the marked reduction in circulating low density lipoprotein (very low density and intermediate density lipoprotein) levels in transgenic mice.
Fluid Flow Induces Upregulation of Synthesis and Release of Tissue Factor Pathway Inhibitor In Vitro
Authors: Westmuckett Andrew D. , Lupu Cristina , Roquefeuil Sylvie , Krausz Thomas , Kakkar Vijay V. , Lupu Florea
Published: June 2011

Abstract
—Fluid flow modulates the synthesis and secretion by endothelial cells (ECs) of several proteins that control the hemostatic properties of the vessel wall. Tissue factor pathway inhibitor (TFPI), also synthesized by ECs, is the main downregulator of tissue factor–dependent procoagulant activity. In the present study, we investigated the effect of physiological shear stress on the expression, distribution, and release of TFPI in cultured ECs. The EA.hy926 cell line was grown in a hollow-fiber perfusion system and exposed for variable times to different shear values: 0.27 dyne/cm
2
(minimal flow), 4.1 dyne/cm
2
(venous flow), and 19 dyne/cm
2
(moderate arterial flow). Step increase of the shear stress from 0.27 to 19 dyne/cm
2
induced a sharp increase of TFPI released into the medium and a parallel decrease and redistribution of cell-associated TFPI, which suggests that an acute release of TFPI occurred from the cellular pools. During 24 hours of high shear stress, cell-associated TFPI antigen and mRNA increased time-dependently. Subjecting ECs to steady shear stress for 72 hours also upregulated the expression and production of TFPI, in direct correlation with the degree of the shear. The secretion of TFPI was enhanced 1.9-fold under venous flow and 2.4-fold under arterial flow compared with minimal flow. Equally, cell-associated TFPI antigen and cell surface TFPI activity increased proportionally with the shear stress. The expression of TFPI mRNA, as determined by Northern blotting, increased up to 2-fold in ECs under venous flow and up to 3-fold under arterial flow. These results suggest that shear forces regulate TFPI by modulating its release and gene expression in ECs in vitro.
Activation of Clotting Factors XI and IX in Patients With Acute Myocardial Infarction
Authors: Minnema M. C. , Peters R. J. G. , de Winter R. , Lubbers Y. P. T. , Barzegar S. , Bauer K. A. , Rosenberg R. D. , Hack C. E. , Cate H. ten
Published: June 2011

Abstract—In acute coronary events, plaque rupture and the subsequent formation of the catalytic tissue factor–factor VIIa complex is considered to initiate coagulation. It is unknown whether clotting factors XI and IX are activated in acute coronary events. Therefore, we prospectively investigated the activation of clotting factors XI and IX as well as activation of the contact system and the common pathway in 50 patients with acute myocardial infarction (AMI), in 50 patients with unstable angina pectoris (UAP), and in 50 patients with stable angina pectoris (SAP). Factor XIa–C1 inhibitor complexes, which reflect acute activation of factor XI, were detected in 24% of the patients with AMI, 8% of the patients with UAP, and 4% of the patients with SAP (P<0.05), whereas factor XIa–α1-antitrypsin complexes, which reflect chronic activation, were observed equally in all 3 study groups. Factor IX peptide levels were significantly higher in the patients with AMI and UAP compared with the patients with SAP (P<0.01). No differences regarding markers of the common pathway were demonstrated. Fibrinopeptide A levels were elevated in patients with AMI compared with patients with UAP and those with SAP (P<0.01). Factor XIIa– or kallikrein–C1 inhibitor complexes were not increased. In conclusion, this is the first demonstration of the activation of clotting factors XI and IX in patients with acute coronary syndromes. Because these clotting factors are considered to be important for continuous thrombin generation and clot stability, their activation might have clinical and therapeutic consequences.