bluuebunny/crossref_metadata_2025 huggingface dataset:
Compositional Differences of LDL Particles in Normal Subjects With LDL Subclass Phenotype A and LDL Subclass Phenotype B
Authors: Capell Warren H. , Zambon Alberto , Austin Melissa A. , Brunzell John D. , Hokanson John E.
Published: June 2011

A predominance of small LDL particles (subclass phenotype B), as determined by gradient-gel electrophoresis is found among patients with myocardial infarction. Despite physical differences in phenotype A and B particles, differences in lipid composition of particles in these phenotypes have yet to be reported in an unselected population of males and females. The present study used lipid/apoB ratios to analyze the amount of lipid per LDL particle, isolated by density-gradient ultracentrifugation, in 70 healthy subjects. Relative to apoB, the LDL particles from phenotype B subjects were found to contain less free cholesterol (0.391±0.05 versus 0.465±0.05; mean±SD;
P
<.001), phospholipid (1.26±0.2 versus 1.43±0.2;
P
<.001), and cholesteryl ester (1.97±0.1 versus 2.11±0.2;
P
<.001) than particles from phenotype A subjects. The amount of triglyceride per LDL particle did not differ between the two phenotypes (0.410±0.1 versus 0.406±0.1;
P
=NS) despite higher plasma triglyceride levels in the phenotype B subjects. LDL size and buoyancy were positively correlated with particle free cholesterol, phospholipid, and cholesteryl ester but not with particle triglyceride. These data suggest that the physical properties of LDL from subjects with phenotype A and B reflect their lipid composition. The compositional differences between LDL particles of the two phenotypes may provide new insight into the increased risk of myocardial infarction in subjects with small, dense LDL.
Urinary Excretion of Apo(a) Fragments
Authors: Kostner Karam M. , Maurer Gerald , Huber Kurt , Stefenelli Thomas , Dieplinger Hans , Steyrer Ernst , Kostner Gert M.
Published: June 2011

The biosynthesis and assembly of lipoprotein(a) [Lp(a)], a marker for atherosclerotic disease, appears to be well understood. However, information is lacking concerning the mode and site of Lp(a) catabolism. Apo(a) is reported to be excreted into the urine. To study the effect of this pathway on the overall catabolism of Lp(a), urinary apo(a) was characterized by immunoblotting. More than 10 distinct apo(a) bands with molecular masses between 30 and 160 kD were observed. Apo(a) fragments were not complexed to apoB. In more than 30 individuals the size of apo(a) bands was comparable irrespective of their apo(a) phenotype, although marked differences in the relative intensities of the bands were observed. Eight batches of 24-hour urine collections collected from one proband at 2-week intervals exhibited a significant correlation between creatinine and apo(a) concentrations as measured by DELFIA (
r
=.93;
P
<.01). In 193 healthy volunteers a highly significant correlation was found between urinary apo(a) concentrations normalized to creatinine levels and plasma Lp(a) values (ρ=0.659;
P
<.0001). Of the total plasma apo(a), 0.073%, ie, 121 μg apo(a), was excreted in the form of apo(a) fragments in 24-hour urine samples from 12 healthy volunteers. We conclude that the catabolism of Lp(a) via excretion of apo(a) fragments accounts for <1% of the daily Lp(a) catabolism.
Atherosclerotic Disease in the Femoral Artery in Hypertensive Patients at High Cardiovascular Risk
Authors: Suurküla Madis , Fagerberg Björn , Wendelhag Inger , Agewall Stefan , Wikstrand John
Published: June 2011

The aim of the present investigation was to examine the occurrence of ultrasound-assessed morphological changes in the right common femoral artery and relate these findings to the ankle-arm index and to symptoms of lower-extremity arterial disease in hypertensive men at high cardiovascular risk (n=143). Comparisons were made with a healthy reference group consisting of age-matched men at low risk (n=46). The results showed that it was possible to obtain high-quality measurements of intima-media thickness in about 80% of all men and that the intraobserver variability was satisfactory (14%). A normal mean intima-media thickness was defined, using data from the low-risk group. Plaque occurrence and mean intima-media thickness in the right common femoral artery were significantly associated with ankle-arm index both in the right and left leg. There were more and larger plaques, as well as thicker mean and maximum intima-media complexes, in the high-risk group than in the low-risk group. In the high-risk group, 11% suffered from symptoms of right lower-extremity artery disease, 20% had an ankle-arm index ≤0.9, 62% had moderate or large plaques (compared with 28% in the low-risk group,
P
<.001), and 77% had an enlarged intima-media complex. The cumulative frequency of signs of atherosclerosis in the right leg was 81% among the 110 patients in whom complete results from all examinations were available. Our conclusion is that ultrasound measurement of the intima-media thickness of the common femoral artery is a valuable method to evaluate morphological changes related to atherosclerotic disease in the lower extremity.
Homozygous Familial Hypobetalipoproteinemia
Authors: Gabelli Carlo , Bilato Claudio , Martini Scipione , Tennyson Gregory E. , Zech Loren A. , Corsini Alberto , Albanese Marco , Brewer H. Bryan , Crepaldi Gaetano , Baggio Giovannella
Published: June 2011

Mutations on the apolipoprotein (apo) B gene that interfere with the full-length translation of the apoB molecule are associated with familial hypobetalipoproteinemia (FHBL), a disease characterized by the reduction of plasma apoB and LDL cholesterol. In this report, we describe an FHBL kindred carrying a unique truncated apoB form, apoB-87
Padova
. Sequence analysis of amplified genomic DNA identified a single G deletion at nucleotide 12 032, which shifts the translation reading frame and causes a termination at amino acid 3978. Two homozygous subjects and seven heterozygous relatives were studied. Although homozygous individuals had only trace amounts of LDL, they were virtually free from the symptoms typical of homozygous FHBL subjects. We investigated the in vivo turnover of radiolabeled normal apoB-100 LDL and apoB-87 LDL in one homozygous patient and two normal control subjects. ApoB-87 LDL showed a similar metabolism in all three subjects, with a fractional catabolic rate more than double that of normal LDL. The rate of entry of apoB-87 in the LDL compartment was also markedly decreased compared with normal apoB-100. The increased in vivo catabolism of apoB-87 LDL was paralleled in vitro by a 2.5-fold increased ability of these particles to inhibit the uptake and degradation of normal apoB-100 LDL by normal human cultured fibroblasts. These results indicate that apoB-87 LDL has an enhanced ability to interact with the LDL receptor; the increased apoB catabolism contributes to the hypobetalipoproteinemia and may explain the mild expression of the disease in the two homozygous individuals.
Influence of Hypercholesterolemia and Adventitial Inflammation on the Development of Aortic Aneurysm in Rabbits
Authors: Freestone T. , Turner R.J. , Higman D.J. , Lever M.J. , Powell J.T.
Published: June 2011

Abdominal aortic aneurysms are characterized by intimal atherosclerosis, disruption and attenuation of the elastic media, and a variable adventitial inflammatory infiltrate. We have developed an animal model of this disorder to evaluate the contribution of hypercholesterolemia, medial injury, and adventitial inflammation to aneurysmal dilatation. To accomplish this, we used periaortic application of calcium chloride, which induced both medial injury with calcification and endothelial injury. Ultrasonography was used to demonstrate the dilatation and thickening of the aortic wall. Over the first 3 weeks after periaortic application of 0.25 mol/L CaCl
2
, the external aortic diameter increased from 3.5±0.5 to 4.2±0.8 mm, but the ID remained unchanged. This apparent wall thickening was accompanied by vascular remodeling, and biochemical changes included ≈50% reduction in tissue hydroxyproline concentration and increased activity of gelatinases (matrix metalloproteinase [MMP]-2 and MMP-9). Independently, cholesterol feeding to induce hypercholesterolemia or the concomitant periaortic application of thioglycollate had little effect on the histological, biochemical, or diameter changes. Together, hypercholesterolemia and thioglycollate were associated with rapid aortic dilatation in CaCl
2
-treated animals but not controls: after 3 weeks, the ID and OD had doubled, the OD increasing from 3.5±0.4 to 7.1±0.4 mm,
P
=.005. The remarkable feature that accompanied this dilatation was the infiltration of cells, mostly foamy macrophages, into the adventitia, with a further reduction in hydroxyproline concentration. Adventitial inflammation may provide the critical stimulus to dilatation of an aorta with preexisting intimal and medial injury.
Circulating Autoantibodies Recognizing Peroxidase-Oxidized Low Density Lipoprotein
Authors: Seccia Milfred , Albano Emanuele , Maggi Elena , Bellomo Giorgio
Published: June 2011

Oxidatively modified LDLs are antigenic and elicit the generation of autoantibodies often detected in plasma and within plaques of atherosclerotic patients. Although Cu
2+
-oxidized LDL and malondialdehyde (MDA)–modified LDL are usually used as antigens in immunoassays, other, still unrecognized epitopes may be formed in vivo during LDL oxidation and may induce antibody production. Antibodies recognizing LDL oxidatively modified by Cu
2+
, 2,2′-azobis-(2-amidino propane) hydrochloride (AAPH), and the combination of horseradish peroxidase and H
2
O
2
(HRP) were detected in serum of a group of 90 unselected patients. HRP-oxidized LDL was the antigen that revealed the highest IgG titers, although the extent of LDL oxidation (evaluated as conjugated diene formation, loss of tryptophan fluorescence, production of fluorescent aldehydic adducts, and change in electrophoretic mobility) was comparable to that obtained with Cu
2+
and AAPH. There was a highly statistically significant correlation between the IgG titers detected using Cu
2+
- and AAPH-oxidized LDLs as antigens, but no correlation was found between the IgG titers revealed by HRP and Cu
2+
or AAPH. In addition, the antibody titers against MDA-modified LDL exhibited a significant correlation with those against Cu
2+
- or AAPH-oxidized LDL but did not correlate with those against HRP-oxidized LDL. Finally, immunocompetition experiments revealed that IgG recognizing HRP-oxidized LDL did not cross-react with Cu
2+
-oxidized LDL and vice versa. The possibility that lipid peroxidation–independent modifications could play a role in HRP-induced formation of antigenic epitopes in LDL was supported by two lines of evidence. First, in probucol-enriched LDL, despite the complete inhibition of lipid peroxidation, HRP, but not Cu
2+
and AAPH, was still able to generate epitopes that were recognized by the same sera reacting with HRP-oxidized native (not probucol-enriched) LDL. In addition, the presence of autoantibodies against Cu
2+
- and AAPH-oxidized LDLs was negatively correlated with serum α-tocopherol concentration, whereas the titers against HRP-oxidized LDL did not exhibit any statistically relevant correlation with α-tocopherol levels. Together, these findings indicate that peroxidase(s)-dependent mechanisms can trigger peculiar lipid peroxidation–independent modifications of LDL in vivo.
Differences in Insulin Suppression of Free Fatty Acid Levels by Gender and Glucose Tolerance Status
Authors: Laws A. , Hoen H.M. , Selby J.V. , Saad M.F. , Haffner S.M. , Howard B.V.
Published: June 2011

Most discussions of relations of insulin resistance to coronary heart disease risk factors have focused on insulin-stimulated glucose uptake, but insulin suppression of plasma free fatty acid (FFA) levels is also important in lipid and lipoprotein metabolism. To identify groups with impaired insulin suppression of FFAs, we studied a multiethnic cohort of 1521 women and men at four US centers that comprise the Insulin Resistance Atherosclerosis Study (IRAS): 682 with normal glucose tolerance, 352 with impaired glucose tolerance, and 487 with non–insulin-dependent diabetes. The FFA level 2 hours after a 75-gm oral glucose load adjusted for fasting FFAs was used as the measure of insulin suppression. After adjustment for age, center, ethnicity, body mass index, and fasting and 2-hour insulin levels, 2-hour FFA levels were significantly higher in men than women and in persons with impaired glucose tolerance and non–insulin-dependent diabetes mellitus versus normal glucose tolerance. The gender difference was largely accounted for by differences in central obesity as measured by waist-hip ratio; the difference by glucose tolerance status was not affected by central obesity, suggesting a different mechanism. In multivariate regression analyses, 2-hour FFA levels were strongly related to fasting triglyceride and apoB levels, respectively, after adjustment for age, fasting and 2-hour insulin concentrations, and fasting FFA concentrations. In summary, elevated plasma apoB and triglyceride concentrations associated with male gender and with glucose intolerance are partly accounted for by differences in the ability of insulin to suppress FFA concentrations.
Cytokine Modulation of LDL Oxidation by Activated Human Monocytes
Authors: Folcik Virginia A. , Aamir Rozina , Cathcart Martha K.
Published: June 2011

AbstractThere is considerable evidence to suggest that cytokines modulate the pathological cellular events that occur in human atherosclerosis. We sought to determine the effects of T-helper-lymphocyte (TH)-1- and TH2-type cytokines on the ability of human monocytes to oxidize LDL, one of the pathological processes believed to occur in atherosclerosis. The ability of opsonized zymosan (ZOP)-activated human monocytes to oxidize LDL in a 24-hour period was significantly enhanced by pretreatment of the monocytes with the TH2 cytokines, interleukin (IL)-4, or IL-13 compared with untreated monocytes. In contrast, interferon (IFN)-γ, a TH1 cytokine, inhibited LDL oxidation by activated monocytes. Treatment with IFN-γ also prevented the IL-4- and IL-13-mediated enhancement of LDL oxidation by ZOP-activated monocytes. Untreated or cytokine-treated unactivated monocytes did not oxidize LDL. The enhancement of LDL oxidation mediated by IL-4 or IL-13 treatment was not due to a mitogenic effect of the cytokines on the monocytes, nor to modulation of superoxide anion (O2−) production. The cytokine regulation of 15-lipoxygenase (LO) in the monocytes was also examined. IL-4 and IL-13 induction of 15-LO mRNA and 15-LO activity in the monocytes was confirmed, as was the previously reported inhibition of induction by IFN-γ. In summary, IL-4 and IL-13 enhance the ability of activated human monocytes to oxidize LDL, whereas IFN-γ inhibits the cell-mediated oxidation. The up- and downregulation of activated monocyte-mediated LDL oxidation by these cytokines correlates with the expression of 15-LO activity. Considerable evidence suggests that the progression of atherosclerosis includes events that are immunologically mediated, lending potential physiological relevance to these in vitro observations.
Effect of Bone Marrow Transplantation on Lipoprotein Metabolism and Atherosclerosis in LDL Receptor–Knockout Mice
Authors: Herijgers Nicole , Van Eck Miranda , Groot Pieter H. E. , Hoogerbrugge Peter M. , Van Berkel Theo J. C.
Published: June 2011

Abstract
The LDL receptor (LDLR) plays an important role in the removal of LDL and its precursors, the intermediate and very low density lipoproteins, from the blood circulation. The receptor is expressed on various cell types. In this study the relative importance of the LDLR on macrophages for lipoprotein metabolism and atherogenesis was assessed. For this purpose, irradiated LDLR-knockout (−/−) mice were transplanted with bone marrow of normal C57BL/6J mice. DNA analysis showed that the transplanted mice were chimeric. The transplantation resulted in a slight decrease of total serum cholesterol when compared with LDLR−/− mice that were transplanted with LDLR−/− bone marrow. This modest decrease, however, did not reach statistical significance at all time points examined. This decrease can be almost completely attributed to a decrease in LDL cholesterol. The specific lowering of LDL cholesterol could clearly be observed at 4 weeks after transplantation, but the decrease was less at 12 weeks after transplantation. Quantification of atherosclerotic lesions of mice fed a 1% cholesterol diet for 6 months revealed that there were no differences in mean lesion area between mice transplanted with wild-type bone marrow or LDLR−/− bone marrow. We anticipate that in LDLR−/− mice transplanted with wild-type bone marrow, the LDLR is downregulated by the relatively high concentrations of circulating cholesterol. In vitro incubations of peritoneal macrophages with
125
I-LDL indicated that the LDLR of these cells could be downregulated by 25-hydroxycholesterol. Peritoneal macrophages isolated from LDLR−/− mice transplanted with wild-type bone marrow, in contrast to those transplanted with LDLR−/− bone marrow, were able to degrade
125
I-LDL, indicating that the capacity to express functional LDLR was achieved. In conclusion, introduction of the LDLR into LDLR -/- mice via bone marrow transplantation resulted in only a relatively modest decrease of LDL cholesterol that became less pronounced at later time points, possibly due to downregulation of the LDLR. To utilize the LDLR in macrophages for effective cholesterol lowering, either the sterol-regulatory elements have to be “silenced” or a high-expression LDLR construct has to be introduced into macrophages, eg, via transplantation of in vitro transfected hematopoietic stem cells.
Heritability Analysis of Lipids and Three Gene Loci in Twins Link the Macrophage Scavenger Receptor to HDL Cholesterol Concentrations
Authors: Knoblauch Hans , Busjahn Andreas , Münter Sylvia , Nagy Zsuzsanna , Faulhaber Hans-Dieter , Schuster Herbert , Luft Friedrich C.
Published: June 2011

Abstract
We studied 100 healthy monozygotic and 72 dizygotic twin pairs (mean age, 34±14 years) to test for genetic influences on blood lipids and to examine relevant gene loci. Total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), and triglyceride (TG) levels were determined after a 12-hour fast. Zygosity was determined with the use of microsatellite markers. Heritability estimates were conducted by using the lisrel 8 program; a sib-pair analysis was conducted by using the sibpal program. Linear regression analyses were carried out between identical-by-descent status and squared within-pair differences of TC, LDL-C, HDL-C, and TG values. Heritability estimates of the lipid serum concentrations ranged from.58 to.66. A significant linkage relationship was found for HDL-C (
P
=.008) and TGs (
P
=.05) with D8S261 on chromosome 8p. However, no linkage was found between any of the lipid variables and the lipoprotein lipase gene locus (LPL GZ14/15 and D8S282). Because D8S261 is located approximately halfway between the LPL and macrophage scavenger receptor genes, we examined the nearby markers D8S549 and D8S1731. Linkage was found for HDL-C and D8S549 (
P
=.001) and for HDL-C and D8S1731 (
P
=.04). On the other hand, we found no linkage between the LDL receptor gene locus and LDL-C serum concentrations nor between the LPL gene locus and the various other lipid fractions. Our data suggest a significant influence of the macrophage scavenger receptor gene locus on HDL-C and weak influence on TG levels. We suggest that inherited variability in the macrophage scavenger receptor gene has an influence on serum lipid concentrations.
Modified LDL Decreases the Binding of Prostaglandin E2,I2,and E1Onto Monocytes in Patients With Peripheral Vascular Disease
Authors: Li S.R. , Yang Q. , Koller E. , Kurtaran A. , Bischof C. , Leimer M. , Rauscha F. , Pidlich J. , Virgolini I.
Published: June 2011

AbstractRecent data suggest that various eicosanoids including prostaglandins play an important regulatory role in the development of atherosclerotic lesions. Peripheral blood monocytes have been implemented in early atherogenesis because they express receptors specific for modified LDL. In this study we investigated the binding of tritium prostaglandins E2(3H-PGE2), E1(3H-PGE1) and I2(3H-PGI2) onto intact peripheral monocytes isolated from 20 patients (32-71 years) with manifested ischemic peripheral vascular disease stage II according to Fontaine and compared the results with those obtained in 16 healthy volunteers (21-68 years). In control subjects, Scatchard analyses of the binding data indicated a single class of high-affinity binding sites for3H-PGE2(maximal binding capacity [Bmax]=11400±3200 sites/cell; dissociation constant [Kd]=1.3±0.5 nmol/L) and two classes of binding sites for3H-PGE1(Bmax1=11200±4900 sites/cell, Kd1=1.5±0.5 nmol/L; Bmax2=47800±6100 sites/cell, Kd2=12.8±5.9 nmol/L) as well as for3H-PGI2(Bmax1=10100±3700 sites/cell, Kd1=1.7 ±0.7 nmol/L; Bmax2=81200±5200 sites/cell, Kd2=14.2±6.5 nmol/L). In the patients, an absence of the higher-affinity binding class and significantly (P<.01) fewer lower-affinity binding sites were found for each ligand (PGE2: Bmax= 6600±3600 sites/cell, Kd=12.1±3.2 nmol/L; PGI2: Bmax=6400 ±3100 sites/cell, Kd=22.1±8.3; PGE1: Bmax=5300±1700 sites/cell, Kd=20.5±7.0 nmol/L). After incubation of monocytes with modified LDL (oxidized LDL or acetylated LDL), the binding of prostaglandins was significantly (P<.01 toP<.001) decreased, whereas native VLDL, LDL, and HDL did not interfere with prostaglandin binding. Prostaglandin-induced adenosine 3′-5′ cyclic monophosphate (cAMP) formation by monocytes was significantly (P<.01) lower in patients (the concentrations causing 50% elevation of basal cAMP formation [ED50] were 3.8±2.4 nmol/L for PGE2, 6.3±3.5 nmol/L for PGE1, and 5.6±4.1 nmol/L for PGI2) than in the control subjects (ED50was 1.6±1.2 nmol/L for PGE2, 4.8±2.5 nmol/L for PGE1, and 3.1±1.4 nmol/L for PGI2). After preincubation with modified LDL, the PG-induced cAMP production by monocytes was remarkably decreased in both patients and control subjects (P<.05). Our results suggest a direct effect of modified LDL on PGE2,PGE1, and PGI2binding onto monocytes by reducing the number of cell surface–expressed receptors available. Modified LDL also reduces the sensitivity of monocytes to prostaglandins, which results in decreased cAMP production. The complex interactions between prostaglandins and lipoproteins may play an important role during atherogenesis.
Thrombospondin-1 Is a Potent Mitogen and Chemoattractant for Human Vascular Smooth Muscle Cells
Authors: Patel Mahendra K. , Lymn Joanne S. , Clunn Gerard F. , Hughes Alun D.
Published: June 2011

Abstract
Thrombospondin-1 (TSP-1) is a matricellular protein that is present in negligible amounts in normal human vasculature but occurs in significant amounts in diseased vessels. In this study, we examined the effect of TSP-1 on DNA synthesis, proliferation, and migration in human vascular smooth muscle cells grown from saphenous vein. TSP-1 (0.1 to 30 μg/mL) elicited a concentration-dependent increase in DNA synthesis under serum-free conditions. In combination with platelet-derived growth factor, TSP-1 induced a synergistic effect on DNA synthesis that was significantly higher than the additive effect of both agents. In proliferation assays, TSP-1 increased cell numbers by 50% relative to the serum-free controls over 14 days. In migration assays, conducted using modified Boyden chambers, TSP-1 (≥10 μg/mL) elicited marked chemotaxis to a degree equivalent to platelet-derived growth factor. The chemotactic response to TSP-1 (10 μg/mL) was abolished by the GRGDSP peptide but unaffected by the control GRGESP peptide, whereas neither peptide inhibited DNA synthesis stimulated by TSP-1. Inhibition of tyrosine kinase activity with genistein or tyrphostin A23 abolished DNA synthesis induced by TSP-1, and a neutralizing antibody to platelet-derived growth factor had no effect on DNA synthesis. Similarly, migration in response to TSP-1 was largely inhibited by these tyrosine kinase inhibitors. TSP-1 is a strong mitogen and chemoattractant for human vascular smooth muscle cells under serum-free conditions. The novel finding that TSP-1 is mitogenic for human cells contrasts with previous studies that have not shown any significant effect of TSP-1 itself on the growth of animal-derived smooth muscle cells. TSP-1 may play an important modulatory role in the local regulation of vascular smooth muscle function in vascular pathologies in humans.
Effect of Coffee Lipids (Cafestol and Kahweol) on Regulation of Cholesterol Metabolism in HepG2 Cells
Authors: Rustan Arild C. , Halvorsen Bente , Huggett Anthony C. , Ranheim Trine , Drevon Christian A.
Published: June 2011

Abstract
We studied the effect of the coffee diterpene alcohols, cafestol and kahweol, on cholesterol metabolism in HepG2 cells. Uptake of
125
I-tyramine cellobiose–labeled LDL was decreased by 15% to 20% (
P
<.05) after 18 hours of preincubation with cafestol (20 μg/mL), whereas 25-hydroxycholesterol reduced uptake by 55% to 65% (
P
<.05). Degradation of LDL in the presence of cafestol was decreased by 20% to 30% (
P
<.05) under the same conditions. The effect of cafestol (20 μg/mL) on uptake and degradation of LDL was greatest (35% to 40%,
P
<.05) after 6 and 10 hours of preincubation, respectively. Furthermore, the effect of cafestol was also dependent on its concentration, and a significant decrease in the LDL uptake (19%) was observed at 10 μg/mL (
P
<.05). Specific binding of LDL was reduced by 17% (
P
<.05) and 60% (
P
<.05) after preincubation with cafestol (20 μg/mL) and 25-hydroxycholesterol (5 μg/mL) for 6 hours, respectively, compared with control cells. Analysis of LDL binding showed that cafestol reduced the number of binding sites for LDL on the cell surface (capacity) by 35% (
P
<.05). In contrast, no significant effect on the level of mRNA for the LDL receptor was observed after incubation with cafestol, whereas 25-hydroxycholesterol reduced the mRNA level for the LDL receptor by 40% to 50% (
P
<.05). A fusion gene construct consisting of a synthetic sterol regulatory element-1 (SRE-1) promoter for the human LDL receptor coupled to the reporter gene for chloramphenicol acetyltransferase (CAT) was transfected into HepG2 cells. No change was observed in CAT activity in SRE-1–transfected cells after incubation with cafestol, whereas 25-hydroxycholesterol reduced CAT activity by 30% to 40% (
P
<.05). Incorporation of [
14
C]acetate into unesterified cholesterol and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity were unaffected in cells incubated with cafestol as well as the cafestol-kahweol mixture compared with control cells. Moreover, cafestol and the cafestol-kahweol mixture did not promote increased incorporation of radiolabeled [
14
C]oleic acid into cholesteryl esters after short-term incubation compared with control cells. On the other hand, 25-hydroxycholesterol caused a 70% to 90% reduction of cholesterol synthesis (
P
<.05) and HMG-CoA reductase activity (
P
<.05), decreased HMG-CoA reductase mRNA level by 70% to 80% (
P
<.05), and promoted a twofold increase in cholesterol esterification (
P
<.05). Finally, no effect of the coffee diterpenes on bile acid formation was observed. These results suggest that cafestol (and kahweol) may reduce the activity of hepatic LDL receptors and thereby cause extracellular accumulation of LDL.
The Angiotensin-Converting Enzyme Gene and the Angiotensin II Type I Receptor Gene as Candidate Genes for Microalbuminuria
Authors: Yudkin John S. , Andres Christine , Mohamed-Ali Vidya , Gould Mairi , Panahloo Arshia , Haines Andrew P. , Humphries Steve , Talmud Phillippa
Published: June 2011

Abstract
Familial clustering of microalbuminuria with cardiovascular disease suggests a possible common genetic antecedent. We have tested the hypothesis that the angiotensin-converting enzyme (ACE) DD genotype and the angiotensin II type I receptor (AT
1
R) gene C allele represent the common link between microalbuminuria and coronary heart disease. The frequency of polymorphisms of the ACE and AT
1
R genes were investigated in 509 nondiabetic white subjects and in 86 non–insulin-dependent diabetic white patients. There was no significant difference in albumin excretion rate between the genotypes in nondiabetic subjects on either a daytime or an overnight sample or in diabetic subjects expressed as a normalized albumin concentration on an untimed morning urine collection. We have found no evidence for an association between polymorphism of the ACE or AT
1
R genes and microalbuminuria in two groups of subjects without insulin-dependent diabetes.
Dose-Response Comparison of
RRR
-α-Tocopherol and All-Racemic α-Tocopherol on LDL Oxidation
Authors: Devaraj S. , Adams-Huet B. , Fuller C.J. , Jialal I.
Published: June 2011

Abstract
Much data have accrued in support of the concept that oxidation of LDL is a key early step in atherogenesis. The most consistent data with respect to micronutrient antioxidants and atherosclerosis appear to relate to α-tocopherol (AT), the predominant lipid-soluble antioxidant in LDL. There are scant data on the direct comparison of
RRR
-AT and all-racemic (
rac)
-AT on LDL oxidizability. Hence, the aim of the present study was to examine the relative effects of
RRR
-AT and all-
rac
-AT on plasma antioxidant levels and LDL oxidation in healthy persons in a dose-response study. The effect of
RRR
-AT and all-
rac
-AT at doses of 100, 200, 400, and 800 IU/d on plasma and LDL AT levels and LDL oxidation was tested in a randomized, placebo-controlled study of 79 healthy subjects. Copper-catalyzed oxidation of LDL was monitored by measuring the formation of conjugated dienes and lipid peroxides over an 8-hour time course at baseline and again after 8 weeks. Plasma AT, lipid-standardized AT, and LDL AT levels rose in a dose-dependent fashion in both the
RRR
-AT and all-
rac
-AT groups compared with baseline. There were no significant differences in plasma, lipid-standardized, and LDL AT levels between
RRR
-AT and all-
rac
-AT supplementation at any dose comparison. The lag phases of oxidation were significantly prolonged with doses ≥400 IU/d of
RRR
-AT and all-
rac
-AT, as measured by conjugated-dienes assay and at 400 IU/d of
RRR
-AT and 800 IU/d of both forms of AT by lipid peroxide assay. Again, there were no significant differences in the lag phase of oxidation at each dose for
RRR
-AT when compared with all-
rac
-AT. Also, there were no significant differences in LDL oxidation after in vitro enrichment of LDL with
RRR
-AT and all-
rac
-AT. Thus, supplementation with either
RRR
-AT or all-
rac
-AT resulted in similar increases in plasma and LDL AT levels at equivalent IU doses, and the degree of protection against copper-catalyzed LDL oxidation was only evident at doses ≥400 IU/d for both forms.
Isoprostanes: Potential Markers of Oxidant Stress in Atherothrombotic Disease
Authors: Patrono Carlo , FitzGerald Garret A.
Published: June 2011

Abstract
Isoprostanes are emerging as a new class of biologically active products of arachidonic acid metabolism of potential relevance to human vascular disease. Their formation in vivo seems to reflect primarily, if not exclusively, a nonenzymatic process of lipid peroxidation. Enhanced urinary excretion of 8-
iso
-PGF
2α
has been described in association with cardiac reperfusion injury and with cardiovascular risk factors, including cigarette smoking, diabetes mellitus, and hypercholesterolemia. Besides providing a likely noninvasive index of lipid peroxidation in these settings, measurements of specific F
2
isoprostanes in urine may provide a sensitive biochemical end point for dose-finding studies of natural and synthetic inhibitors of lipid peroxidation. Although the biological effects of 8-
iso
-PGF
2α
in vitro suggest that it and other isoeicosanoids may modulate the functional consequences of lipid peroxidation, evidence that this is likely in vivo remains inadequate at this time.
CLA-1 Is an 85-kD Plasma Membrane Glycoprotein That Acts as a High-Affinity Receptor for Both Native (HDL, LDL, and VLDL) and Modified (OxLDL and AcLDL) Lipoproteins
Authors: Calvo Dominica , Gómez-Coronado Diego , Lasunción Miguel A. , Vega Miguel A.
Published: June 2011

AbstractLipoprotein metabolism is regulated by the functional interplay between lipoprotein components and the receptors and enzymes with which they interact. Recent evidence indicates that the structurally related glycoproteins CD36 and SR-BI act as cell surface receptors for some lipoproteins. Thus, CD36 has been reported to bind oxidized LDL (OxLDL) and acetylated LDL (AcLDL), while SR-BI also binds native LDL and HDL. The cDNA of human CLA-1 predicts a protein 509 amino acids long that displays a 30% and an 80% amino acid identity with CD36 and mouse or hamster SR-BI, respectively. In this report, we describe the structural characterization of CLA-1 as an 85-kD plasma membrane protein enriched in N-linked carbohydrates. The expression of CLA-1 on mammalian and insect cells has been used to demonstrate that CLA-1 is a high-affinity specific receptor for the lipoproteins HDL, LDL, VLDL, OxLDL, and AcLDL. Northern blot analysis of the tissue distribution of CLA-1 in humans indicated that its expression is mostly restricted to tissues performing very active cholesterol metabolism (liver and steroidogenic tissues). This finding, in the context of the capability of this receptor to bind to both native and modified lipoproteins, strongly suggests that the CLA-1 receptor contributes to lipid metabolism and atherogenesis.
Immunohistochemical Colocalization of the Terminal Complex of Human Complement and Smooth Muscle Cell α-Actin in Early Atherosclerotic Lesions
Authors: Torzewski Michael , Torzewski Jan , Bowyer David E. , Waltenberger Johannes , Fitzsimmons Colin , Hombach Vinzenz , Gabbert Helmut E.
Published: June 2011

Abstract
There is substantial evidence that activated components of the complement cascade are present in atherosclerotic lesions, and it was suggested some years ago that smooth muscle cells may be an important target of complement attack by the terminal components of the cascade, C5b-9, also called the membrane attack complex. Recent in vitro studies have shown that assembly of membrane attack complex on smooth muscle cells leads to the release of monocyte chemotactic protein-1, and, if this were to occur in vivo, then it could be responsible for the recruitment of monocytes into the lesion. In this study we have investigated the localization of C5b-9 in early atherosclerotic lesions of human coronary arteries, collected from autopsies, by immunohistochemical staining. C5b-9 was found to colocalize widely with smooth muscle cell α-actin, but not with intact macrophages, thus supporting the hypothesis that interaction of complement with smooth muscle cells may indeed be important in atherogenesis.
Compensatory Enlargement in Coronary and Femoral Arteries Is Related to Neither the Extent of Plaque-Free Vessel Wall Nor Lesion Eccentricity
Authors: Clarijs J. A. G. M. , Pasterkamp G. , Schoneveld A. H. , van Leeuwen T. G. , Hillen B. , Borst C.
Published: June 2011

Abstract
Arteries may demonstrate compensatory enlargement in response to plaque accumulation. It has been proposed that enlargement is achieved by the expansion of the nondiseased (plaque-free) vessel wall. In this study, we assessed this hypothesis. Post mortem, 32 atherosclerotic coronary arteries (left anterior descending, n=10; left circumflex, n=11; and right coronary, n=11) and 54 atherosclerotic femoral arteries were pressure fixed. Cross sections (coronary arteries, n=537; femoral arteries, n=1602) were obtained for analysis every 2.5 mm for the coronary arteries and every 5.0 mm for the femoral arteries. From these cross sections, we determined the degree of remodeling and an eccentricity index. Finally, we measured the extent of plaque-free vessel wall. The plaque-free vessel wall was defined as (1) no plaque present or (2) plaque thickness <0.5 mm. A very weak, negative correlation was observed between the degree of remodeling and the extent of the plaque-free vessel wall (coronary arteries: no plaque
r
2
=.13,
P
<.01; <0.5 mm plaque
r
2
=.15,
P
<.05; femoral arteries: no plaque
r
2
=.02,
P
<.01; <0.5 mm plaque
r
2
=0.04,
P
<.01). The degree of remodeling did not correlate with the eccentricity index (coronary arteries
r
2
=.002,
P
>.05 and femoral arteries
r
2
=.001,
P
>.05). Thus, compensatory enlarged segments did not reveal a larger circumference of plaque-free vessel wall compared with segments that failed to enlarge. This study provides no support for the hypothesis that nondiseased vessel-wall expansion is responsible for compensatory enlargement in atherosclerotic arteries.
Soluble Vascular Cell Adhesion Molecule-1 as a Biohumoral Correlate of Atherosclerosis
Authors: De Caterina Raffaele , Basta Giuseppina , Lazzerini Guido , Dell’Omo Giulia , Petrucci Roberto , Morale Marco , Carmassi Franco , Pedrinelli Roberto
Published: June 2011

AbstractVascular cell adhesion molecule-1 (VCAM-1) is a protein expressed on the surface of activated endothelial cells and expressed in early atherosclerosis. Because part of the protein is shed in the circulation and can be detected in peripheral plasma [soluble (s)VCAM-1], we hypothesized that sVCAM-1 may be a circulating marker of the presence and severity of atherosclerosis in humans. We selected 11 patients with essential hypertension plus peripheral vascular disease (PVD) and matched them for age, gender, body mass index, and smoking habits with 11 patients with uncomplicated essential hypertension (UH) and 11 healthy controls. We evaluated plasma concentrations of sVCAM-1 along with those of the soluble form of two other endothelial leukocyte adhesion molecules [sE-selectin and s-intercellular adhesion molecule-1 (sICAM-1)] and other markers of endothelial dysfunction/damage [s-thrombomodulin, plasminogen activator inhibitor type I, and von Willebrand factor (vWF)]. We also measured insulin, glucose, fibrinogen, total and HDL cholesterol, and the urinary albumin excretion (UAE), which may also be related to atherosclerosis. Results of these assays were related to the echographic assessment of the maximum intima-media thickness (IMTmax) at the carotid bifurcation, as an index of atherosclerosis in the carotids. PVD patients had a clearly elevated IMTmax[2.7 (1.1-3.1) mm, median (range)] compared with both UH patients [1.2 (0.8-2.4) mm] and controls [1 (0.6-2) mm]. sVCAM-1 was clearly higher in PVD patients [990 (273-1808) ng/mL, median (range)] versus 340 (236-975) ng/mL in UH and 386 (204-835) ng/mL in controls, and it separated clinical categories better than sICAM-1, vWF, glucose, insulin, UAE, triglycerides, or total, LDL or HDL cholesterol. sVCAM-1 was also the best biohumoral correlate of IMTmax(R=.59;P<.001) in univariate analysis. Because many of the biohumoral variables assessed were mutually intercorrelated, they were entered in a multivariate analysis to assess their contribution in explaining IMTmaxvariability. sVCAM-1 remained the only independent predictor of IMTmaxand totally abolished the contribution of other variables to IMTmaxvariability. Thus, sVCAM-1 is a good biohumoral correlate of overt atherosclerosis, independent of underlying hypertension, and may be an in vivo marker of endothelial activation. Its potential value as a surrogate for global risk assessment and its behavior in intervention studies remain to be determined.
Phosphoproteins Regulated by the Interaction of High-Density Lipoprotein With Human Skin Fibroblasts
Authors: Garver William S. , Deeg Mark A. , Bowen Rosario F. , Culala Maria M. , Bierman Edwin L. , Oram John F.
Published: June 2011

Abstract
Interaction of HDL with cells activates protein kinase C (PKC), a process that may be important in stimulating efflux of excess cellular cholesterol. Here we report that HDL treatment of cholesterol-loaded fibroblasts increases
32
P labeling of three acidic phosphoproteins. These phosphoproteins, called pp80, pp27, and pp18 based on apparent
M
r
in kD, were also phosphorylated by acute treatment of cells with phorbol myristate acetate, suggesting that they are regulated in response to PKC activation. The HDL-stimulated phosphorylation of pp80 and pp18 was significant after only 30 seconds and was sustained for at least 30 and 120 minutes, respectively, while increased phosphorylation of pp27 was transient, reaching a maximum at 10 minutes. Both pp27 and pp18 were phosphorylated on serine/threonine residues, whereas pp80 was phosphorylated on serine/threonine and tyrosine residues. Immunoprecipitation studies suggested that pp80 is the myristoylated alanine-rich C kinase substrate protein, but the identities of pp27 and pp18 are unknown. HDL and trypsin-digested HDL stimulated phosphorylation of pp80 and pp27, while purified apoA-I, apoA-II, or apoE had no stimulatory effects, indicating that the active component in HDL was trypsin resistant and unlikely to be an apolipoprotein. Conversely, HDL, apoA-I, apoA-II, and apoE all stimulated pp18 phosphorylation, while trypsin-digested HDL had less effect, consistent with pp18’s being responsive to HDL apolipoproteins. Treatment of cholesterol-depleted cells with apoA-I also stimulated phosphorylation of pp18, but only transiently. These results suggest that HDL interaction with cells activates diverse PKC-mediated pathways that target different phosphoproteins. Of these three phosphoproteins, only pp18 has a phosphorylation response consistent with its being involved in apolipoprotein-mediated lipid transport.
Relation of LDL Size to the Insulin Resistance Syndrome and Coronary Heart Disease in American Indians
Authors: Gray R. Stuart , Robbins David C. , Wang Wenyu , Yeh Jeunliang L. , Fabsitz Richard R. , Cowan Linda D. , Welty Thomas K. , Lee Elisa T. , Krauss Ronald M. , Howard Barbara V.
Published: June 2011

Abstract
Small, dense LDL has been shown to be associated with the insulin resistance syndrome and coronary heart disease (CHD). We examined the distribution of LDL size and phenotype within a population-based sample of American Indians to determine the relationships with prevalent CHD and to examine associations with hyperinsulinemia and other components of the insulin resistance syndrome. Data were available for 4505 men and women between 45 and 74 years of age who are members of 13 American Indian communities in three geographic areas. Diabetes, CHD, and CHD risk factors were assessed by standardized techniques, and LDL size was measured by gradient gel electrophoresis. LDL size was smaller in men than in women and in individuals with diabetes than in those without diabetes. In multivariate analysis, LDL size was significantly related to several components of the insulin resistance syndrome, including triglycerides (inversely) and HDL cholesterol (positively). Although univariate relations were positive, LDL size was not significantly related to fasting insulin concentrations or body mass index in the multivariate model. LDL size also showed no relationship to apolipoprotein E phenotype. When LDL size was compared in individuals with and without CHD, no significant differences were observed, either in nondiabetic or diabetic individuals. We conclude that LDL size is most strongly related to lipoprotein components of the insulin resistance syndrome, especially plasma triglycerides. However, in this population with low LDL, it is not related to cardiovascular disease.
In Vitro Interactions of Oxidatively Modified LDL With Type I, II, III, IV, and V Collagen, Laminin, Fibronectin, and Poly-
d
-Lysine
Authors: Greilberger Joachim , Schmut Otto , Jürgens Günther
Published: June 2011

Abstract
The accumulation of LDL in the arterial intima is considered a key event in atherogenesis. We investigated the binding of oxidized LDL (ox-LDL) to microtiter plates coated with type I or II collagen, laminin, fibronectin, or poly-
d
-lysine. Oxidation of LDL,
125
I-LDL, or Eu
3+
-LDL was performed with CuCl
2
, varying the time of oxidation. Bound lipoprotein was assessed by counting radioactivity or fluorescence in the wells. Binding of highly ox-LDL in PBS followed the order: type I collagen>poly-
d
-lysine>type II collagen>laminin>fibronectin. Comparing various collagen types, the binding of ox-LDL followed the order: type I>type V and, type III>type IV>type II collagen. Binding of ox-LDL in PBS was dependent on an increase in negative charge of ox-LDL. Testing certain amino acids as competitors for binding of highly ox-LDL to type I collagen put lysine first, followed by arginine and histidine. On laminin, histidine competed most, followed by lysine and arginine. When studying the influence of Na
+
, K
+
, Ca
2+
, Mg
2+
(equivalent to their concentrations in the interstitial fluid), native LDL, moderately ox-LDL, and highly ox-LDL showed the same affinity to type I collagen. However, a fivefold dilution of the buffer increased the affinity of moderately and highly ox-LDL 3.9- and 10-fold compared with native LDL. Application of the F(ab′)
2
from a monoclonal antibody to ox-LDL revealed a strong competition of the binding of highly ox-LDL to type II collagen (60%), laminin (35%), type I collagen (20%), and poly-
d
-lysine (15%), whereas the binding to fibronectin was not affected.
The Role of a Triplet Repeat Sequence of the Very Low Density Lipoprotein Receptor Gene in Plasma Lipid and Lipoprotein Level Variability in Humans
Authors: Helbecque Nicole , Dallongeville Jean , Codron Valérie , Arveiler Dominique , Ruidavets Jean-Bernard , Evans Alun , Cambien François , Fruchart Jean-Charles , Amouyel Philippe
Published: June 2011

Abstract
The biological role of the very low density lipoprotein receptor (VLDL-R) in humans is not yet elucidated. This cellular receptor binds apolipoprotein E (apoE)-containing lipoparticles and is mainly expressed in peripheral tissues. The
VLDL-R
gene contains a polymorphic triplet (CGG) repeat located 19 bp upstream of the initiation codon. We explored the allelic distribution of this repeat in 1384 subjects of European Caucasian origin, 609 of them surviving a myocardial infarction. Six alleles corresponding to 5, 6, 7, 8, 9, and 11 repeats were detected in this population. The alleles 5, 8, and 9 were the most frequent, with frequencies of 0.413, 0.275, and 0.292, respectively. No association was found between the
VLDL-R
polymorphism and myocardial infarction. In controls without lipid lowering treatment, a statistically significant interaction between
VLDL-R
genotype and apoE phenotype was found for plasma triglycerides (
P
<.04), suggesting a gene-gene interaction. There was also a main effect of the
VLDL-R
polymorphism on LpE:B and LpA-I. The
VLDL-R
9 allele was associated with lower levels of plasma LpE:B (
P
<.05) and higher concentrations of plasma LpA-I (
P
<.01) than the other alleles. These results suggest that
VLDL-R
has a modest influence on circulating lipoproteins in humans.