bluuebunny/crossref_metadata_2025 huggingface dataset:
Monounsaturated Versus Polyunsaturated Dietary Fat and Serum Lipids
Authors: Gardner Christopher D. , Kraemer Helena C.
Published: June 2011

Abstract
The objective of this study was to examine whether oils high in monounsaturated or polyunsaturated fats have a differential effect on serum lipid levels, using a meta-analytical approach. Fourteen studies (1983 through 1994) were identified that met six inclusion criteria, the primary criterion being that a study have at least two intervention diets that varied in monounsaturated and polyunsaturated fat content but were otherwise similar in total fat, saturated fat, fiber, and dietary cholesterol. Seven studies included a comparable high-saturated fat diet. Standardized effect sizes (observed treatment difference in mean end-point lipid levels, divided by the pooled SD) were calculated for individual studies, then individual effect sizes were pooled. The results indicated no significant differences in total, LDL, or HDL cholesterol levels when oils high in monounsaturated or polyunsaturated fats were compared directly. Triglyceride levels were modestly but consistently lower on the diets high in polyunsaturated fats (
P
=.05). Replacement of saturated fat with either monounsaturated or polyunsaturated fat led to significant decreases in total and LDL cholesterol (
P
<.001), and the pooled effect sizes were comparable for either type of unsaturate (effect sizes ranged from −0.64 to −0.68, ie, roughly a decrease of 0.65 mmol/L [25 mg/dL] relative to the high-saturated fat diets). Neither type of unsaturated fat significantly changed HDL cholesterol or triglyceride levels relative to the high-saturated fat diets. In conclusion, the evidence from this meta-analysis strongly indicates there is no significant difference in LDL or HDL cholesterol levels when oils high in either monounsaturated or polyunsaturated fats are exchanged in the diet. Any dietary recommendations for the use of one in preference to the other should be based on outcomes other than serum cholesterol levels.
β-Glycerophosphate Accelerates Calcification in Cultured Bovine Vascular Smooth Muscle Cells
Authors: Shioi Atsushi , Nishizawa Yoshiki , Jono Shuichi , Koyama Hidenori , Hosoi Masayuki , Morii Hirotoshi
Published: June 2011

AbstractCalcification is a common feature of advanced atherosclerotic lesions and is being reemphasized as a clinically significant element of vascular disease. However, the scarcity of in vitro models of vascular calcification preclude studying its molecular and cellular mechanism. In the present study, we describe an in vitro calcification system in which diffuse calcification can be induced by culturing bovine vascular smooth muscle cells (BVSMC) in the presence of β-glycerophosphate, ascorbic acid, and insulin in a manner analogous to in vitro mineralization by osteoblasts. Calcification was confirmed by von Kossa staining and45Ca accumulation. Factor analysis revealed that β-glycerophosphate is the most important factor for this calcification process, suggesting that alkaline phosphatase (ALP) may be involved. As predicted, high levels of ALP expression were detected by ALP assay and Northern blot analysis. Functional significance of ALP was confirmed by demonstrating that levamisole, a specific inhibitor of ALP, inhibited BVSMC calcification in a dose-dependent manner. Bisphosphonates such as etidronate and pamidronate potently inhibited BVSMC calcification, suggesting that hydroxyapatite formation may be involved. Importantly, expression of osteopontin mRNA was dramatically increased in calcified BVSMC compared with uncalcified control cells. These data suggest that β-glycerophosphate can induce diffuse calcification by an ALP–dependent mechanism and that this in vitro calcification system is useful for analyzing the molecular and cellular mechanisms of vascular calcification.
Differing α-Tocopherol Oxidative Lability and Ascorbic Acid Sparing Effects in Buoyant and Dense LDL
Authors: Tribble Diane L. , Thiel Patrick M. , van den Berg Jeroen J.M. , Krauss Ronald M.
Published: June 2011

Abstract
The enhanced oxidizability of smaller, more dense LDL is explained in part by a lower content of antioxidants, including ubiquinol-10 and α-tocopherol. In the present studies, we also observed greater rates of depletion of α-tocopherol (mole per mole LDL per minute) in dense (
d
=1.040 to 1.054 g/mL) compared with buoyant (
d
=1.026 to 1.032 g/mL) LDL in the presence of either Cu
2+
or the radical-generating agent 2,2′-azobis(2-amidinopropane)dihydrochloride. Differences were particularly pronounced at the lowest Cu
2+
concentration tested (0.25 μmol/L), with a fivefold greater rate in dense LDL. At higher concentrations (1.0 and 2.5 μmol/L Cu
2+
), there was a greater dependence of depletion rate on initial amount of α-tocopherol, which was reduced in dense LDL, thus resulting in smaller subfraction-dependent differences in depletion rates. Inclusion of ascorbic acid (15 μmol/L), an aqueous antioxidant capable of recycling α-tocopherol by hydrogen donation, was found to extend the course of Cu
2+
-induced α-tocopherol depletion in both buoyant and dense LDL, but this effect was more pronounced in dense LDL (time to half-maximal α-tocopherol depletion was extended 15.6-fold and 21.2-fold in buoyant and dense LDL, respectively, at 2.5 μmol/L Cu
2+
;
P
<.05). Thus, dense LDL exhibits more rapid α-tocopherol depletion and conjugated diene formation than buoyant LDL when oxidation is performed in the absence of ascorbic acid, but these differences are reversed in the presence of ascorbic acid. These results suggest that differences in oxidative behavior among LDL density subfractions may involve differences in antioxidant activity and thus that the efficacy of antioxidant regimens designed to inhibit LDL oxidation in vivo may vary in relation to interindividual variations in LDL particle distribution profiles.
Distribution and Correlates of Plasma Fibrinogen in Middle-aged Women
Authors: Stefanick Marcia L. , Legault Claudine , Tracy Russell P. , Howard George , Kessler Craig M. , Lucas Diane L. , Bush Trudy L.
Published: June 2011

Abstract
Fibrinogen levels have been reported in cohort and case-control studies to be positively related to the development of coronary heart disease. This report presents the distribution and determinants of fibrinogen in women enrolling in a 3-year randomized trial of hormone replacement therapy (HRT), the Postmenopausal Estrogen/Progestin Interventions (PEPI) trial. Fasting plasma fibrinogen levels were measured in 874 postmenopausal women, aged 45 to 65 years, who had not used HRT for at least 3.5 months. Mean (±SD) fibrinogen level was 2.83±0.45 g/L. There was a significant positive association between fibrinogen and age (
P
=.03). Significantly higher (
P
<.005) fibrinogen levels were seen in current smokers versus nonsmokers (2.94 versus 2.81 g/L), in women who reported consuming fewer than 12 alcoholic drinks in the 12 months before the baseline visit versus higher consumption (2.90 versus 2.79 g/L), and in women who reported never versus ever having used HRT (2.90 versus 2.77 g/L). Self-reported leisure time physical activity (LTPA) was negatively associated (
P
=.0001) with fibrinogen levels as follows: inactive (2.84 g/L), light (2.89 g/L), moderate (2.80 g/L), and heavy (2.60 g/L), with significantly (
P
=.0001) lower levels in women who reported heavy LTPA versus each of the other categories and in women reporting moderate versus light LTPA. A strong positive correlation was found between fibrinogen and body mass index (BMI) (
r
=.32;
P
<.0001). In a model that included age, smoking, alcohol intake, prior HRT, LTPA, and BMI, LTPA was no longer a statistically significant predictor of fibrinogen level, while associations with other variables remained significant. Fibrinogen was positively associated (
P
<.001) with waist, hip, and thigh girths and waist-to-hip ratio, but these relationships were no longer significant after adjustment for BMI. In contrast, negative associations with HDL cholesterol (
r
=−.25;
P
<.001) and positive associations with LDL cholesterol (
r
=.16;
P
<.001) remained significant (
P
<.01 and
P
<.05, respectively) after simultaneous adjustment for age, smoking, alcohol, prior HRT, LTPA, and BMI. Statistically significant univariate associations between fibrinogen and triglycerides, insulin and glucose levels before and after oral glucose, and blood pressure were not seen in multivariate analyses. In summary, higher fibrinogen levels were shown to be significantly and independently related to several major lifestyle and physical characteristics known to be associated with increased risk of cardiovascular disease in women.
Lysophosphatidylcholine Inhibits Relaxation of Rabbit Abdominal Aorta Mediated by Endothelium-Derived Nitric Oxide and Endothelium-Derived Hyperpolarizing Factor Independent of Protein Kinase C Activation
Authors: Cowan Conrad L. , Steffen Robert P.
Published: June 2011

Abstract
Hypercholesterolemia is associated with increased oxidized LDL and impaired endothelium-dependent relaxation (EDR). An inhibitory component of oxidized LDL is lysophosphatidylcholine (LPC). To determine the effect and mechanism(s) of action of LPC on EDR mediated by endothelium-derived nitric oxide (EDNO) and endothelium-derived hyperpolarizing factor (EDHF), rabbit abdominal aortic rings were suspended for measurement of isometric tension and studied under three conditions: control; with 25 mmol/L K
+
buffer to isolate relaxation mediated by EDNO; and in rings treated with
N
ω
-nitro-
l
-arginine methyl ester (L-NAME, 30 μmol/L) to isolate relaxation mediated by EDHF. Incubation with LPC (10 and 30 μmol/L) for 30 minutes inhibited EDR in a concentration-dependent manner. LPC (30 μmol/L) significantly inhibited maximal relaxation to acetylcholine in control, 25 mmol/L K
+
–, and L-NAME–treated rings (77.1±7.8%, 42.1±8.9%, and 3.4±7.7%) compared with untreated rings (99.0±0.9%, 90.9±2.2%, and 54.7±4.7%,
P
<.05). Inhibition of relaxation was specific to endothelium-dependent responses in that relaxation to direct smooth muscle vasodilators (papaverine, 8-bromo-cGMP, and sodium nitroprusside) were unaltered by LPC. The inhibition by LPC (30 μmol/L) was not due to cytotoxicity, because EDR returned to normal levels after repeated washing with physiological salt solution containing 0.1% albumin. Coincubation with protein kinase C inhibitors, staurosporine (20 nmol/L) or calphostin C (1 μmol/L), had no effect on the EDR inhibition by LPC (30 μmol/L). Furthermore, LPC continued to inhibit EDR in rings in which protein kinase C was downregulated by incubation for 18 hours with 1 μmol/L phorbol 12-myristate 13-acetate (PMA). The inhibition of EDR to the receptor-independent agonist A23187 by LPC (30 μmol/L) but not by PMA (30 nmol/L) further supports a lack of effect of LPC on protein kinase C. Thus, the inhibitory effect of LPC on EDR is not limited to EDNO but also inhibits relaxation mediated by EDHF. Also, the inhibition of relaxation to EDNO and EDHF is not mediated by activation of protein kinase C.
Relation Between Insulin Resistance, Hyperinsulinemia, Postheparin Plasma Lipoprotein Lipase Activity, and Postprandial Lipemia
Authors: Jeppesen Jorgen , Hollenbeck Clarie B. , Zhou M.-Y. , Coulston Ann M. , Jones Claire , Chen Y.-D. Ida , Reaven Gerald M.
Published: June 2011

Abstract
We examined the relation between insulin resistance, plasma glucose and insulin responses to meals, lipoprotein lipase (LPL) activity, and postprandial lipemia in a population of 37 healthy nondiabetic individuals. Plasma glucose and insulin concentrations were determined at frequent intervals from 8
am
through midnight (breakfast at 8
am
and lunch at noon); resistance to insulin-mediated glucose disposal was determined by measuring the steady-state plasma glucose (SSPG) concentration at the end of a 180-minute infusion of glucose, insulin, and somatostatin; LPL activity was quantified in postheparin plasma; and postprandial concentrations of triglyceride (TG)-rich lipoproteins were assessed by measuring the TG and retinyl palmitate content in plasma and the Svedberg flotation index (S
f
) >400 and S
f
20 to 400 lipoprotein fractions. Significant simple correlation coefficients were found between various estimates of postprandial lipemia and SSPG (
r
=.38 to .68), daylong insulin response (
r
=.37 to .58), daylong glucose response (
r
=.10 to .39), and LPL activity (
r
=−.08 to −.58). However, when multiple regression analysis was performed, only SSPG remained independently associated with both postprandial TG and retinyl palmitate concentrations. These data provide evidence that insulin resistance plays an important role in regulating the postprandial concentration of TG-rich lipoproteins, including those of intestinal origin.
Two Different Allelic Mutations in a Finnish Family With Lecithin:Cholesterol Acyltransferase Deficiency
Authors: Miettinen H. , Gylling H. , Ulmanen I. , Miettinen T. A. , Kontula K.
Published: June 2011

AbstractLecithin:cholesterol acyltransferase (LCAT) deficiency is a genetic disorder associated with low levels of serum HDL cholesterol. The proband of the Finnish LCAT-deficient family had corneal opacities, proteinuria, anemia with stomatocytosis, low serum HDL cholesterol (0.27 mmol/L), and low LCAT activity. Sequence analysis of his LCAT gene revealed compound heterozygosity for two different mutations: a C insertion in exon 1 between nucleotides 932 and 937 and a C-to-T point mutation in exon 6 at position 4976. The C insertion in exon 1 is predicted to result in premature termination and a truncated polypeptide containing only 16 amino acids. The C-to-T point mutation in exon 6 substitutes cysteine for arginine at residue 399. The functional significance of the Arg399→Cys mutation was examined by expressing the mutated and wild-type LCAT cDNAs in COS cells. COS cells transfected with mutated and wild-type cDNAs showed comparable levels of mature LCAT mRNA. However, LCAT activity in the cell media of COS cells transfected with the mutant LCAT cDNA was significantly lower than that of COS cells transfected with the wild-type cDNA (1.4% versus 12.0% cholesterol esterified, respectively). A polymerase chain reaction–based duplex assay, in which both mutations can be detected simultaneously, was used for preliminary screening of Finnish subjects with serum HDL levels below 0.9 mmol/L; two additional individuals heterozygous for the Arg399→Cys mutation were identified. In conclusion, two different allelic mutations in the LCAT gene have been identified in a Finnish family, a C insertion between nucleotides 932 and 937 and a C-to-T transversion at position 4976, and a convenient polymerase chain reaction–based assay suitable for regional population screening and differential diagnosis of low serum HDL was developed.
A Common Variant in the Gene for Lipoprotein Lipase (Asp9→Asn)
Authors: Mailly France , Tugrul Yesim , Reymer Paul W. A. , Bruin Taco , Seed Mary , Groenemeyer Björn F. , Asplund-Carlson Anette , Vallance David , Winder Anthony F. , Miller George J. , Kastelein John J. P. , Hamsten Anders , Olivecrona Gunilla , Humphries Steve E. , Talmud Philippa J.
Published: June 2011

AbstractSubjects with combined hyperlipidemia (CHL) were screened for mutations in the lipoprotein lipase (LPL) gene by single-strand conformational polymorphism, and a previously reported G→A DNA sequence change in exon 2, causing substitution of Asp by Asn at position 9, was identified in 2 individuals. Because this substitution destroys a recognition site forTaqI, pooling of DNA samples, amplification, and digest withTaqI allowed the rapid screening of 1563 healthy individuals and patients of Dutch, Swedish, English, and Scottish origin. In the general populations of all four countries, healthy carriers of the mutation were detected at a frequency of 1.6% to 4.4% (mean, 3.0%; 95% confidence interval, 2.0% to 4.0%). The frequency of carriers was roughly twice as high (range, 4.0% to 9.8%) in selected patients with CHL or type IV hyperlipoproteinemia or in subjects with angiographically assessed atherosclerosis; the frequency was consistently higher in each patient group compared with its matched control group. In 773 healthy men from two general practices in the United Kingdom, 25 carriers and 2 homozygotes for the mutation were identified. In these 27, plasma triglyceride but not plasma cholesterol levels were significantly higher than in noncarriers (2.25 versus 1.82 mmol/L,P<.02), and this difference was maintained in three subsequent annual measurements. Postheparin LPL activity data were available for some carriers and for 7 of 9 individuals from the patient groups, and 6 of 6 individuals from the control groups had LPL activity that was lower than the respective group mean. In vitro mutagenesis and transient expression in COS cells showed that compared with the LPL-Asp9 construct, LPL-Asn9 activity and mass were reduced by 20% to 30% in the culture media. Overall however, LPL-Asn9 had only slightly reduced specific activity (by 18%). Thus, although the precise mechanism of the effect is unclear, the data strongly suggest that the LPL-Asn9 variant is associated with and may play a direct role in predisposing carriers to develop hypertriglyceridemia.
Basic Fibroblast Growth Factor Is a Signal for the Initiation of Centrosome Redistribution to the Front of Migrating Endothelial Cells at the Edge of an In Vitro Wound
Authors: Ettenson David S. , Gotlieb Avrum I.
Published: June 2011

Abstract
Rapid, efficient repair of the endothelium following focal endothelial wounding and denudation is regulated by a complex series of cellular processes. Directed cell migration, an early essential event in repair, is thought to be initiated by centrosome redistribution toward the front of the cell prior to the onset of migration. As such, centrosomal polarity may be an important regulatory event in directed endothelial cell migration. Little is known about the regulation of this process. To study this further, in vitro wounds were created down the middle of confluent porcine aortic endothelial monolayers by mechanical denudation. Conditioned media collected 1 hour after wounding contained basic fibroblast growth factor (bFGF). Antibodies directed against bFGF added to the cultures at the time of wounding significantly inhibited cell migration and transiently inhibited centrosome redistribution. When transcription was transiently inhibited with actinomycin D, present at 1 hour before and for 1 hour after wounding, the cells moved more slowly (5.2±2.8 versus 22.7±5.7 μm/h for control), taking five times longer for the wound to close. Throughout this period, centrosomes did not reorient to the front of the cells. When either recombinant bFGF or conditioned medium collected from control cultures at 1 hour after wounding was added 23 hours after actinomycin D was washed out (at which time RNA synthesis returned to control levels), the centrosomes redistributed to the front of the cells, and cells migrated at a rapid rate (17.2±4.2 μm/h), similar to control. However, the recombinant bFGF or conditioned media had no effect when added immediately after actinomycin D was removed, ie, when RNA synthesis was still inhibited. Thus, bFGF initiates centrosome redistribution by stimulating processes that lead to the transcription of as yet unknown essential gene(s) that are induced immediately following wounding, and this appears to be at least one mechanism by which bFGF enhances aortic endothelial migration and repair at the site of an endothelial wound.
Repression of the Macrophage Scavenger Receptor in Macrophage–Smooth Muscle Cell Heterokaryons
Authors: Rommeswinkel Matthias , Severs Nicholas J. , Köster Mathias , Robenek Horst
Published: June 2011

AbstractMacrophage scavenger receptors mediate the uptake of chemically modified LDL in an unregulated manner, leading to massive intracellular accumulation of lipid and thus a foamy cellular morphology. In atherosclerotic lesions, foam cells originate not only from macrophages but also from smooth muscle cells, yet smooth muscle cells do not normally express scavenger receptors, and when exposed to chemically modified LDL in vitro, lipid accumulation does not occur. The mechanism of conversion of smooth muscle cells into foam cells in the arterial wall is thus still under discussion. To investigate whether direct interaction between macrophages and smooth muscle cells may be involved and to explore the effects of components of the two cell types on the expression of scavenger receptors, we report here experiments using somatic cell hybrids formed by fusion of the two cell types. Immunofluorescent labeling and confocal microscopic techniques were applied to investigate and measure (1) lipid accumulation (using Nile Red staining), (2) the binding and uptake of acetylated LDL (using 1,1′-dioctadecyl-1-3,3,3′,3′-tetramethylindocarbocyanine perchlorate–labeled acetylated LDL), and (3) receptor expression (assessed using a specific anti-receptor antibody) in smooth muscle cell–macrophage heterokaryons, macrophage-macrophage homokaryons, smooth muscle cell–smooth muscle cell homokaryons, and unfused macrophages and smooth muscle cells. The results demonstrate that scavenger receptor expression becomes repressed in macrophage–smooth muscle cell heterokaryons but not in macrophage-macrophage homokaryons. One possible explanation for the observed repression would be the existence of a negative regulatory cytoplasmic factor produced by smooth muscle cells.
Induction of GPIb/IX-vWF Receptor-Ligand Translocation on Surface-Activated Platelets
Authors: White James G. , Krumwiede Marlys D. , Cocking-Johnson Debra , Escolar Gines
Published: June 2011

Abstract
Multimers of von Willebrand factor (vWF) readily bind to glycoprotein (GP) Ib/IX receptors on spread human platelets and cover the cell from edge to edge. Addition of anti-vWF antibody to spread platelets covered with vWF caused the multimers to move from peripheral margins into caps over platelet centers. Despite almost complete centralization of receptor-ligand complexes, a significant number of GPIb/IX receptors capable of binding multimers remained available on the peripheral zone. Fixation followed by a second incubation with vWF, anti-vWF, and staph protein A coupled to 5-nm gold particles (PAG
5
) revealed multimers extending from the centrally concentrated cap of vWF to cell margins. If spread platelets with central caps of vWF were exposed a second time to multimers and anti-vWF antibody before fixation and stained with PAG
5
after, the residual GPIb/IX receptors and second wave of vWF formed a ring around the cap, leaving a clear margin. If after fixation and staining with PAG
5
the grids with caps and rings of vWF were washed, exposed a third time to vWF, refixed, and then incubated with anti-vWF and PAG
10
, the clear margin was covered with multimers of vWF forming a second ring around the first circle of receptor-ligand complexes. Thin sections of spread platelets with central caps of GPIb/IX-vWF complexes revealed only rare examples of uptake by the open canalicular system. The interaction of GPIb/IX with vWF multimers observed in the present study suggests a mechanism by which platelets under high shear forces may adhere and attach firmly to a denuded vascular surface.
Association Between Circulating Immune Complexes, Complement C4 Null Alleles, and Myocardial Infarction Before Age 45 Years
Authors: Lefvert Ann Kari , Hamsten Anders , Holm Göran
Published: June 2011

AbstractOne hundred patients who had survived a myocardial infarction before the age of 45 years and 90 age- and sex-matched healthy individuals were investigated for circulating immune complexes (CICs) and the presence of complement C4 null alleles (C4Q0). CICs were found in increased concentrations in 20% of patients and 6.7% of control subjects. Patients and control subjects had the same prevalence of C4Q0. CICs were present in all patients and in 36% of the control subjects homozygous for C4Q0. Patients and control subjects heterozygous for C4Q0 had CICs in 71% and 0%, respectively. The high prevalence and a high concentration of CICs were particularly associated with C4A*Q0. Patients homozygous for C4A*Q0 had concentrations of LDL that were lower than found in other patients. The increased concentration of CICs associated with genetic deficiencies of the complement factor C4 might thus be an additional etiological factor for the development of chronic vascular damage and premature myocardial infarction.
Association Between β-Carotene and Acute Myocardial Infarction Depends on Polyunsaturated Fatty Acid Status
Authors: Kardinaal Alwine F.M. , Aro Antti , Kark Jeremy D. , Riemersma Rudolph A. , van ’t Veer Pieter , Gomez-Aracena Jorge , Kohlmeier Lenore , Ringstad Jetmund , Martin Blaise C. , Mazaev Vladimir P. , Delgado-Rodriguez Miguel , Thamm Michael , Huttunen Jussi K. , Martin-Moreno José M. , Kok Frans J.
Published: June 2011

Abstract
Because antioxidants may play a role in the prevention of coronary heart disease by inhibiting the peroxidation of polyunsaturated fatty acids (PUFAs), the combined association of diet-derived antioxidants and PUFAs with acute myocardial infarction (MI) was investigated. This multicenter case-control study included 674 patients and 725 control subjects in eight European countries and Israel. Fatty acid composition and α-tocopherol and β-carotene levels were determined in adipose tissue; selenium level was determined in toenails. For α-tocopherol no association with MI was observed at any PUFA level. The overall multivariate odds ratio (OR) for low (10th percentile) versus high (90th percentile) β-carotene was 1.98 (95% confidence interval [CI], 1.39 to 2.82). The strength of this inverse association with MI was dependent on PUFA levels (in tertiles): for low PUFA, the OR for low versus high β-carotene was 1.79 (95% CI, 0.98 to 3.25), for medium PUFA the OR was 1.76 (95% CI, 1.00 to 3.11), and for high PUFA 3.47 (95% CI, 1.93 to 6.24). For selenium increased risk was observed only at the lowest PUFA tertile (OR, 2.49; 95% CI, 1.22 to 5.09). This interaction between selenium and PUFAs was not significant and may at least partly be explained by a higher proportion of smokers at the low PUFA level. These findings support the hypothesis that β-carotene plays a role in the protection of PUFAs against oxidation and subsequently in the protection against MI. No evidence was found that α-tocopherol or selenium may protect against MI at any level of PUFA intake.
Gender-Related Association Between β-Fibrinogen Genotype and Plasma Fibrinogen Levels and Linkage Disequilibrium at the Fibrinogen Locus in Greenland Inuit
Authors: de Maat Moniek P.M. , de Knijff Peter , Green Fiona R. , Thomas Angela E. , Jespersen Jørgen , Kluft Cornelis
Published: June 2011

Abstract
Elevated plasma fibrinogen levels represent an increased risk for cardiovascular disease, but the mechanism explaining this association is still not clear. Genetic differences may play a role, because it has been shown that individuals who carry the rare alleles of polymorphisms in the genes for the Bβ-chain (
Bcl
I and G/A
−455
) and the Aα-chain (
Taq
I) of fibrinogen have higher plasma fibrinogen levels and that patients with peripheral arterial disease have a higher frequency of the rare allele of the
Bcl
I polymorphism than do healthy control subjects. We studied the Greenland Inuit, a population with a low incidence of ischemic heart disease; polymorphisms of the fibrinogen gene; and their association with plasma fibrinogen level. The group studied had a small age range (30 to 34 years), 97% were smokers, 62 were men, and 71 were women. We observed that in the Inuit, frequencies of the rare alleles of the β gene and of the common alleles of the α gene polymorphisms were lower than those published for other populations (all Caucasian). Accordingly, in the Inuit, these distribution patterns give a higher frequency of alleles that are associated with lower plasma fibrinogen levels. We further observed comparable linkage disequilibrium between α and β gene polymorphisms in Caucasian populations. In Inuit men the rare allele of the
Bcl
I and G/A
−455
fibrinogen polymorphisms was associated with plasma fibrinogen level comparable with the association described in Caucasian populations. In women, however, we did not find a significant association, supporting the desirability of separate data analysis for men and women of the influence of genetic factors on atherosclerotic disease. In conclusion, in the Inuit the association of fibrinogen polymorphisms with fibrinogen levels is comparable with that in Caucasians, but the genes that are associated with lower fibrinogen levels are more frequent in the Inuit than in Caucasians.
Predilection of Atherosclerosis for the Inner Curvature in the Femoral Artery
Authors: Smedby Ö. , Johansson J. , Mölgaard J. , Olsson A. G. , Walldius G. , Erikson U.
Published: June 2011

Abstract
The degree of atherosclerosis in the inner and outer curvature of the femoral artery was studied by using digitized angiography and edge-roughness calculations in 301 hyperlipidemic patients. When the two edges of the vessel were compared no significant difference was seen, but when the local curvature was taken into account, inner curves were found to be more atherosclerotic than outer curves, and both inner and outer curves were more affected than straight segments. The same pattern was encountered in subpopulations defined by clinical or blood lipid criteria. The suggested explanation is that flow disturbances such as low shear rates or separated flow, which tend to arise along the inner curvature, promote the development of atherosclerosis.
Determinants of Lipid Levels Among Children With Heterozygous Familial Hypercholesterolemia in Norway
Authors: Tonstad Serena , Leren Trond P. , Sivertsen Mette , Ose Leiv
Published: June 2011

AbstractThree founder mutations have been discovered among individuals with familial hypercholesterolemia (FH) in Norway: FHElverumand FHSvartor, predicted to be null alleles, and FHC210G, predicted to disrupt the secondary structure of the ligand-binding domain. To clarify the effect of these and other mutations on lipid levels and parental history of premature cardiovascular disease, we examined 164 boys and girls ages 6 to 16 years with heterozygous FH. Among all children, serum cholesterol levels of the FH parent, percent body fat, pubertal stage, and serum cholesterol levels of the non-FH parent, but not apo E polymorphism, were significant determinants of LDL cholesterol levels in a stepwise multiple regression equation and explained 40% (95% confidence interval [CI], 25% to 55%) of the variance in LDL cholesterol. Among boys, percent body fat, dietary sucrose, and apo E genotype determined 31% (95% CI, 14% to 49%) of the variance in triglyceride levels; whereas among girls, only percent body fat was associated with triglyceride levels. Percent body fat was not associated with LDL cholesterol or triglyceride levels in the FHC210Ggroup. The children’s and FH parents’ lipid levels and premature cardiovascular disease among parents were similar among the null-allele and defective-protein groups and in those with an undetected mutation. These data confirm that the phenotypic expression of FH in childhood is influenced by modifiable lifestyle characteristics and by genetic factors other than the underlying mutation and raise the possibility that body fatness may interact with genotype in determining lipid levels.
Probucol Treatment Decreases Serum Concentrations of Diet-Derived Antioxidants
Authors: Elinder Liselotte Schäfer , Hådell Karin , Johansson Jan , Mølgaard Jørgen , Holme Ingar , Olsson Anders G. , Walldius Göran
Published: June 2011

Abstract
The effect of probucol, which is both a cholesterol-lowering drug and an antioxidant, on the serum concentrations of diet-derived antioxidants vitamin E, β-carotene, lycopene, and vitamin A was studied in 303 hypercholesterolemic subjects. In a 3-year, double-blind, randomized trial we investigated to determine whether combined treatment with diet, cholestyramine, and probucol could reduce the progression of femoral atherosclerosis. Serum and lipoprotein antioxidant levels were measured by reverse-phase high-performance liquid chromatography. Cholestyramine significantly lowered serum concentrations of vitamin E by 7%, β-carotene by 40%, and lycopene by 30% (all
P
<.001) due to impairment of gastrointestinal absorption and to serum cholesterol lowering. Probucol reduced serum vitamin E by 14% (
P
<.001) secondary to cholesterol and triglyceride lowering. The carotenoids were reduced by probucol by 30% to 40% (
P
<.001) most probably due to reductions in lipoprotein particle size and to competition with these substances for incorporation into VLDL during its assembly in the liver. This study shows that the use of a lipid-soluble antioxidant and cholesterol-lowering drug may have unfavorable effects on blood levels of diet-derived antioxidants.
Efficacy of a National Cholesterol Education Program Step 2 Diet in Normolipidemic and Hypercholesterolemic Middle-Aged and Elderly Men and Women
Authors: Schaefer Ernst J. , Lichtenstein Alice H. , Lamon-Fava Stefania , Contois John H. , Li Zhengling , Rasmussen Helen , McNamara Judith R. , Ordovas José M.
Published: June 2011

Abstract
We tested the effects of a National Cholesterol Education Program (NCEP) Step 2 diet (30% of calories or less as total fat, less than 7% saturated fat, and less than 200 mg cholesterol per day) on plasma lipid levels in normocholesterolemic and hypercholesterolemic middle-aged and elderly men and women. Thirty-two subjects were studied. Eight normolipidemic subjects (6 men and 2 women, mean age 56±13 years) with LDL cholesterol levels of less than 4.14 mmol/L (160 mg/dL) were given a baseline diet similar in composition to the diet currently consumed in the United States (35% of calories as total fat and 14% as saturated fat, with 147 mg cholesterol per 1000 kcal) for 6 weeks. Subjects were then placed on an NCEP Step 2 diet (26% total fat, 4% saturated fat, 45 mg cholesterol per 1000 kcal) for 24 weeks. In addition, 24 subjects (12 men and 12 women, mean age 62±12 years) with moderate hypercholesterolemia (LDL cholesterol levels of 4.14 mmol/L or above) were given a baseline diet for 6 weeks and then the NCEP Step 2 diet for 6 weeks. Energy intakes were adjusted to keep body weight constant throughout the study. In both normolipidemic and hypercholesterolemic subjects, consumption of the NCEP Step 2 diet was associated with significant changes in levels of total cholesterol (−20% and −16%, respectively), LDL cholesterol (−21% and −18%, respectively), and HDL cholesterol (−16% and −15%, respectively). The plasma total cholesterol/HDL cholesterol ratio and plasma triglyceride, VLDL cholesterol, and lipoprotein(a) levels were not affected by the diet in either group. Similar responses were seen in men and women. The range of diet responsiveness in the 32 subjects was very large, with LDL cholesterol changes ranging from +5% to −40%. Thus, an NCEP Step 2 diet is effective in significantly reducing total and LDL cholesterol levels without changing the total cholesterol/HDL cholesterol ratio under controlled isoweight conditions in middle-aged and elderly normolipidemic and hypercholesterolemic men and women. The wide individual variation in diet responsiveness may indicate genetic variability.
Active Site–Blocked Factors VIIa and IXa Differentially Inhibit Fibrin Formation in a Human Ex Vivo Thrombosis Model
Authors: Kirchhofer Daniel , Tschopp Thomas B. , Baumgartner Hans R.
Published: June 2011

Abstract
The role of tissue factor/factor VIIa (FVIIa) and factor VIIIa/factor IXa (FVIIIa/FIXa) complexes in thrombus formation was examined in a human ex vivo blood flow system by use of active site–blocked FVIIa (FVIIai) and FIXa (FIXai) as selective inhibitors. Blood was drawn directly from the veins of volunteers into a mixing device where FVIIai and FIXai were mixed with flowing blood. The blood then entered parallel-plate chambers containing coverslips coated with human fibrillar collagen or tissue factor–expressing cell layers of tumor necrosis factor–α–stimulated human endothelial cells, human smooth muscle cells, and J82 cells. Exposure of stimulated endothelial cells to blood flowing at a venous shear rate of 65/s led to fibrin deposition, which was inhibited by infusion of FVIIai (IC
50
, 3 nmol/L), as quantified by microdensitometry of fibrin-stained coverslips. Whereas FIXai (600 nmol/L) was only a weak inhibitor, FVIIai (60 nmol/L) reduced fibrinopeptide A (FPA) plasma levels from 504±79 to 171±27 ng/mL and concomitantly inhibited platelet thrombus deposition. Similarly, experiments with smooth muscle cells and J82 cells showed that FVIIai but not FIXai efficiently reduced FPA levels. Conversely, with tissue factor–free collagen, which induces platelet-dependent fibrin formation, infusion of FIXai but not of FVIIai inhibited fibrin deposition (IC
50
, 8 nmol/L) and reduced FPA levels from 55±8 to 9±5 ng/mL. However, FIXai did not affect the number of platelet thrombi deposited on collagen. The results suggest that fibrin formation on tissue factor–expressing cellular surfaces is initiated by tissue factor/FVIIa–dependent direct activation of factor X, while on the tissue factor–free collagen surface, factor X activation and subsequent fibrin formation is dependent on the platelet FVIIIa/FIXa complex.
Molecular Regulation of the Bovine Endothelial Cell Nitric Oxide Synthase by Transforming Growth Factor–β
1
Authors: Inoue Nobutaka , Venema Richard C. , Sayegh Hassan S. , Ohara Yuichi , Murphy T. J. , Harrison David G.
Published: June 2011

Abstract
The promoter region of the endothelial cell nitric oxide synthase (ecNOS) gene contains potential response elements for transforming growth factor–β
1
(TGFβ
1
). TGFβ
1
plays an important role in the pathogenesis of atherosclerosis, vascular hypertrophy, and angiogenesis. We therefore sought to determine whether TGFβ
1
might modulate ecNOS expression in bovine aortic endothelial cells (BAEC). TGFβ
1
increased ecNOS mRNA in a dose-dependent manner. TGFβ
1
also increased ecNOS protein content. The production of nitrogen oxides (NO
x
), assessed by chemiluminescence, and nitric oxide synthase activity, assessed by arginine/citrulline conversion, were increased in TGFβ
1
-treated cells. Transcriptional activity of the 5′-flanking promoter region of the ecNOS gene was increased by TGFβ
1
, as assessed by transfection with promoter/luciferase constructs. Deletion analysis suggested that the TGFβ
1
-response element was present between nucleotides −1269 and −935 from the first transcription start site, in which a putative nuclear factor–1 (NF-1) binding site existed. Gel shift assays showed that nuclear protein(s), immunologically similar to CCAAT transcription factor/NF-1, bound to the putative NF-1 binding site in a sequence-specific manner. Mutation of the putative NF-1 binding site in the promoter/luciferase construct significantly decreased the responsiveness to TGFβ
1
. In conclusion, TGFβ
1
increases ecNOS expression associated with an increase in production of NO in BAEC. This response is probably mediated by transcriptional activation of the ecNOS gene promoter.
Fibrinogen and Factor VIII, but Not Factor VII, Are Associated With Measures of Subclinical Cardiovascular Disease in the Elderly
Authors: Tracy Russell P. , Bovill Edwin G. , Yanez David , Psaty Bruce M. , Fried Linda P. , Heiss Gerardo , Lee Marshal , Polak Joseph F. , Savage Peter J.
Published: June 2011

AbstractNo studies have examined the associations of coagulation factor levels with measures of subclinical cardiovascular disease (CVD) in the elderly. The Cardiovascular Health Study (CHS) is a prospective, population-based cohort study of CVD in persons older than 65 years. At the baseline examination, we measured fibrinogen, factor VII, and factor VIII levels in 5024 of the 5201 participants of the CHS and examined the associations of these coagulation factors with measures of subclinical CVD in a cross-sectional analysis. Subclinical CVD measures were based on electrocardiography, carotid ultrasonography, echocardiography, and ankle-arm blood pressure measurements (AAI). For analyses, we used the full cohort as well as two mutually exclusive subgroups: those with prevalent clinical CVD at baseline and those without. Fibrinogen and to a lesser extent factor VIII showed positive associations with a variety of subclinical CVD measures. In age-adjusted analyses, fibrinogen and factor VIII were significantly associated with 8 of 10 measures. In multivariate analyses, fibrinogen was significantly associated with carotid artery stenosis, internal (but not common) carotid artery wall thickness, and AAI. Factor VIII was associated with abnormal wall motion and AAI in the full cohort only. Factor VII was not consistently associated with subclinical disease measures. In bivariate analyses that included data from all three groups, there were 5 positive subclinical disease associations and 5 negative associations for factor VII. In multivariate analyses, there were no significant associations between factor VII and subclinical CVD in the full cohort or in either subgroup. We conclude that in these cross-sectional analyses, fibrinogen and to a lesser extent factor VIII are associated with subclinical CVD in the elderly, even in those without symptoms or a history of clinical CVD. Factor VII, however, was not associated with subclinical CVD in the elderly.
ApoA-IHelsinki(Lys107→0) Associated With Reduced HDL Cholesterol and LpA-I:A-II Deficiency
Authors: Tilly-Kiesi Marju , Qiuping Zhang , Ehnholm Sonja , Kahri Juhani , Lahdenperä Sanni , Ehnholm Christian , Taskinen Marja-Riitta
Published: June 2011

AbstractA Finnish kindred with premature coronary heart disease and decreased HDL cholesterol levels was identified as having an apoA-I variant, apoA-I (Lys107→0), caused by a 3-bp deletion of nucleotides 1396 through 1398 in exon 4 of the apoA-I gene. These subjects (n=10) were heterozygous for this mutation. The mean serum HDL cholesterol concentration (26.7±9.7 mg/dL) of affected family members was 36% lower than that of unaffected family members (P<.05). Mean serum apoA-I and apoA-II concentrations in heterozygotes were reduced by 18% and 22%, respectively, compared with normal family members (P<.05). In heterozygotes the mean concentration of lipoprotein containing both apoA-I and apoA-II (LpA-I:A-II) was 31% lower than in those with normal apoA-I (P<.001), while the mean level of lipoproteins containing apoA-I without apoA-II was similar in the two groups. HDL density-gradient ultracentrifugation showed a lack of HDL2and small dense HDL3in heterozygotes compared with unaffected family members. The HDL particle size distribution, as analyzed by nondenaturing gradient gel electrophoresis of heterozygotes, revealed one major peak at 8.0 to 9.7 nm, a minor peak at 7.8 to 8.5 nm, and an absence of HDL2band HDL2apeaks. These latter peaks were observed in unaffected family members. Serum levels of LDL cholesterol, triglycerides, VLDL, IDL, and LDL subclasses were similar in the two groups. However, in heterozygotes the cholesterol-to-triglyceride ratios in VLDL2, LDL1, LDL3, HDL2b, HDL2a, and HDL3awere 8% to 54% lower than in unaffected family members (P<.05). Cholesteryl ester transfer protein activity in heterozygotes was reduced by 25% compared with unaffected family members (P<.05), while the plasma lecithin:cholesterol acyltransferase (LCAT) activity did not differ between heterozygotes and unaffected family members. The ability of isolated variant apoA-I to serve as a cofactor for LCAT in vitro did not differ from that of normal apoA-I. Our data are consistent with the concept that a low HDL cholesterol level in subjects heterozygous for the apoA-IHelsinkimutation (Lys107→0) having normal LCAT activity is a consequence of decreased concentration of LpA-I:A-II particles and of a smaller size and reduced cholesterol content of HDL particles.
Segregation Analysis of HDL3-C Levels in Families of Patients Undergoing Coronary Arteriography at an Early Age
Authors: Coresh J. , Beaty T.H. , Prenger V.L. , Xu J. , Kwiterovich P.O.
Published: June 2011

AbstractHDL cholesterol (HDL-C) level is a risk factor for coronary heart disease. Studies have shown a strong genetic influence on HDL-C levels in addition to environmental influences, but no definite major gene control has been demonstrated. Since HDL subfractions may better reflect the actions of distinct metabolic alterations than total HDL, we tested the hypothesis that the amount of cholesterol in the denser HDL3subfraction (HDL3-C) is under the control of a major gene. The study population included 676 family members of 116 probands who underwent coronary arteriography at an early age (men ≤50 and women ≤60 years). HDL3-C level was measured by using enzymatic methods after preparative ultracentrifugation at a density of 1.125 g/mL. HDL3-C was adjusted for age, gender, alcohol consumption, and smoking, which combined accounted for 3% of its variance. Segregation analysis was conducted on adjusted HDL3-C by using regressive models. The familial correlations for HDL3-C levels were spouse .03±.08, parent-offspring .14±.05, and sibling .24±.05. The data strongly supported a codominant mendelian model, with the common allele coding for lower HDL3-C levels and the rarer allele (frequency, 25%) coding for higher HDL3-C levels. This major gene explained 34% of the variation in HDL3-C levels and 9% of the variation in total HDL-C levels. These results suggest that HDL3-C levels exhibit clearer genetic control than total HDL-C and may therefore be a useful target for further genetic studies.
Effects of Iron- and Hemoglobin-Loaded Human Monocyte–Derived Macrophages on Oxidation and Uptake of LDL
Authors: Yuan Xi Ming , Brunk Ulf T. , Olsson Anders G.
Published: June 2011

AbstractIt is generally accepted that transition metals are required for cellular LDL oxidation. LDL may also be oxidized by iron and reducing agents in cell-free systems. We hypothesized that lysosomal iron may be exocytosed from macrophages that have been iron loaded by phagocytosis and degradation of iron-rich structures, eg, erythrocytes, and that such released iron may promote LDL oxidation and uptake by macrophages. Human monocyte–derived macrophages (HMDMs) were isolated and cultured for 7 days and then exposed to FeCl3, Fe-ADP, or Fe-EDTA (100 μmol/L) or hemoglobin (25 or 50 μg/mL) for 24 hours. After rinsing, LDL (50 to 150 μg/mL) was added in fresh culture medium without serum. After another 24 hours the media concentrations of iron and thiobarbituric acid–reacting substances as well as the electrophoretic mobility of LDL were increased, while the cells showed only minimal signs of decreased viability. Lipofuscin, neutral lipids, and phospholipids accumulated in a granular, lysosome-like pattern, and the cells acquired a foam cell–like morphology. There was a strong correlation (r=.87,P=.005) between the amount of iron added during the pre-exposure period and lipofuscin accumulation during the ensuing exposure to LDL in fresh, serum-free medium. Our results support our hypothesis and indicate that lysosomal iron may be exocytosed from HMDMs and promote oxidation and uptake of LDL and thus induce foam cell formation.