bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Relationship Between Measures of HDL Phenotypes and Insulin Concentrations
Authors: Rainwater David L. , Mitchell Braxton D. , Mahaney Michael C. , Haffner Steven M.
Published: June 2011

Abstract
We used data from the San Antonio Family Heart Study to determine the HDL correlates of the insulin resistance syndrome (IRS), as reflected by insulin concentrations in nondiabetic subjects. We measured insulin concentrations both in the fasting state and 2 hours after a glucose challenge (2-hour insulin) and we assessed seven aspects of HDL phenotype, including size and concentration of both lipid and protein components. Measurements were obtained from 1202 nondiabetic members of 42 families. Initial quantitative genetic analyses revealed that a substantial portion of phenotypic variation in the nine variables was due to genes (heritabilities, h

2

, ranged from 0.32 to 0.47). We then conducted a series of bivariate genetic analyses, which indicated that there were significant additive genetic correlations (ie, pleiotropy) between the two measures of insulin and five of seven HDL measures tested, including concentrations of HDL cholesterol (fasting insulin only) and triglyceride, and HDL size distributions of apoAI, apoAII, and cholesterol; concentrations of apoAI and apoAII were not genetically related to either insulin measure. Increased insulin levels were associated with relatively smaller HDL phenotypes, and considering a similar association with small, dense LDLs, this finding suggests a common effect of insulin resistance on particle size distributions for these lipoproteins. Thus, these results suggest the existence of genes that pleiotropically influence variation in both HDLs and insulin levels and therefore contribute to the clustering of proatherogenic traits in the IRS.
Inhibition of Platelet-Derived Growth Factor BB–Induced Expression of Glyceraldehyde- 3-Phosphate Dehydrogenase by Sodium Butyrate in Rat Vascular Smooth Muscle Cells
Authors: Ranganna Kasturi , Yatsu Frank M.
Published: June 2011

AbstractGlyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key regulatory enzyme of glycolysis, which exists in nuclei and functions as a DNA-binding protein as well as a nuclear protein, appears to be modulated by cellular activities. Exposure of quiescent rat smooth muscle cells (SMCs) to platelet-derived growth factor BB (PDGF-BB), which stimulates SMCs proliferation, caused a time-dependent increase in mRNA for GAPDH and its catalytic activity. Treatment of quiescent SMCs with sodium butyrate (SB), which is shown to inhibit PDGF-BB-induced SMC proliferation, caused a time- and concentration-dependent decrease in PDGF-BB-induced GAPDH mRNA expression and its catalytic activity. Nuclear run-on studies revealed that the PDGF-BB-induced rate of GAPDH gene transcription was reduced by about 50% in the presence of 5 mmol/L SB. The protein synthesis inhibitor, cycloheximide, failed to abolish the SB-inhibited PDGF-BB-induced rate of transcription of GAPDH, suggesting that SB is not dependent on ongoing protein synthesis to exert its effects on PDGF-BB-induced GAPDH transcription. Furthermore, measurement of GAPDH mRNA stability at various times after the inhibition of transcription with actinomycin D indicated that 5 mmol/L SB has no significant effect on the half-life of PDGF-BB-induced mRNA. The reduction in PDGF-BB-induced GAPDH expression by SB is probably caused by a cycloheximide-insensitive transcriptional mechanism. Thus, the inhibition of PDGF-BB-induced expression of GAPDH by SB suggests a link between SMC proliferation, energy consumption, and GAPDH gene upregulation.
Triflavin Inhibits Platelet-Induced Vasoconstriction in De-endothelialized Aorta
Authors: Sheu J.-R. , Yen M. H. , Hung W. C. , Lee Y. M. , Su C. H. , Huang T. F.
Published: June 2011

Abstract
Triflavin, a 7.5-kD cysteine-rich polypeptide purified from
Trimeresurus favoviridis
snake venom, belongs to a family of Arg-Gly-Asp-(RGD)–containing peptides, termed disintegrins. In this study, aggregating human platelets dose- dependently induced vasoconstriction in de-endothelialized isolated rat thoracic aortas. At 5×10
7
cells per milliliter, platelets induced a peak tension averaging 65±7.2% of the tension induced by phenylephrine (10 μmol/L). The relative effectiveness of RGD-containing peptides (including venom peptides triflavin and trigramin, small RGD synthetic peptides Gly-Arg-Gly-Asp-Ser [GRGDS], Gly-Arg-Gly-Asp-Phe [GRGDF], and Gly-Arg-Gly-Asp-Ser-Pro-Lys [GRGDSPK]) was examined by testing the inhibitory effect on aggregating platelet-induced vasoconstriction in de-endothelialized aorta. Triflavin (1 μmol/L) significantly inhibited the platelet-induced vasoconstriction, whereas neither trigramin (10 μmol/L) nor small RGD peptides (2 mmol/L) (ie, GRGDS, GRGDF, and GRGDSPK) showed any significant effect. The release of serotonin and the formation of thromboxane A
2
from aggregating platelets were both significantly inhibited by triflavin (2 μmol/L), whereas trigramin and small RGD-containing peptides showed no significant effect. On scanning electron micrographs of de-endothelialized aorta, aggregating platelets adhered to the subendothelium, with loss of their discoid shape, to form irregular spheres with pseudopod extensions. Triflavin (2 μmol/L) markedly reduced the adhesion of platelets to the subendothelium in the same aorta. Furthermore, RGD-containing peptides (including triflavin, trigramin, and small RGD-containing peptides) inhibited the adhesion of 10 μg/mL collagen-activated platelets to extracellular matrices (ie, fibronectin, vitronectin, and von Willebrand factor). It is concluded that the marked ability of triflavin to inhibit aggregating platelet-induced vasoconstriction in de-endothelialized aorta compared with other RGD-containing peptides (including trigramin), may be due at least partly to triflavin’s efficiently preventing the activation of platelets subsequent to inhibition of serotonin release and thromboxane A
2
formation. However, the different abilities of triflavin compared with other RGD-containing peptides was not related to the ability to inhibit adhesion of platelets to extracellular matrices. Therefore, from the results of this study, it appears that triflavin may be a useful therapeutic agent for the treatment of thromboembolism and its associated angiospasm.
Endothelial Cells Prevent Accumulation of Lipid Hydroperoxides in Low-Density Lipoprotein
Authors: Smalley David M. , Hogg Neil , Kalyanaraman B. , Pritchard Kirkwood A.
Published: June 2011

Abstract
A variety of cell types, including endothelial cells, oxidize low-density lipoprotein (LDL). To investigate the mechanisms by which endothelial cells modulate LDL oxidation states, endothelial cell cultures were incubated with LDL (240 mg cholesterol/dL) for 24 hours in M199 supplemented with fetal bovine serum (FBS, 16.7%). These conditions were not toxic to endothelial cells over the time frame of the study. Changes in LDL oxidation were monitored by measuring thiobarbituric acid–reactive substances (TBARS), lipid hydroperoxide (LOOH), and conjugated dienes (A
234nm
). LDL medium incubated in the absence of endothelial cells contained higher TBARS than did LDL medium incubated with endothelial cells (0.35±0.08 versus 0.23±0.08 nmol MDA/mg, respectively). LOOHs were higher in LDL medium incubated without endothelial cells than in LDL medium incubated with endothelial cells (6.8±4.4 versus 0.49±0.89 nmol/mg, respectively). Conjugated diene formation, based on changes in absorbance at 234 nm, increased to a greater extent in LDL medium incubated in the absence of endothelial cells than when endothelial cells were present. To increase oxidative stress on the endothelial cell cultures, increasing concentrations of Cu
2+
(0 to 4 μmol/L) were added to LDL medium. Endothelial cells prevented LOOH accumulation until the concentration of Cu
2+
exceeded 0.75 μmol/L. At 1.5 and 4 μmol/L Cu
2+
, endothelial cells enhanced LOOH formation nearly 3 and 2.5 times the LOOH values in the corresponding medium incubated in the absence of endothelial cells. This loss of protective function however, was not permanent. Endothelial cells, preincubated for 24 hours with Cu
2+
-containing LDL medium, were still able to prevent LOOH accumulation in fresh LDL medium. Endothelial cells prevented LOOH accumulation even when exposed to LDL medium that contained low concentrations of LOOHs (<22 nmol/mg). However, endothelial cells accelerated the accumulation of LOOHs in LDL when exposed to LDL medium that contained slightly higher concentrations of preexisting LOOHs (≈33 nmol/mg). These data indicate that endothelial cells have a limited capacity for preventing LOOH formation and that small increases in LOOHs may play a critical role in enhancing the potential of endothelial cells for oxidative modification of LDL.
Bcl
I Polymorphism in the Fibrinogen β-Chain Gene Is Associated With the Risk of Familial Myocardial Infarction by Increasing Plasma Fibrinogen Levels
Authors: Zito Francesco , Di Castelnuovo Augusto , Amore Concetta , D’Orazio Andria , Donati Maria Benedetta , Iacoviello Licia
Published: June 2011

Abstract
The aim of this study was to investigate the association of the
Bcl
I β-chain fibrinogen polymorphism with the risk of acute myocardial infarction (AMI) and its relationship with fibrinogen levels in the Italian population. We studied 102 AMI patients, selected within the framework of the GISSI-2 trial, who had a familial history of arterial thrombosis (at least one first-degree relative suffering from AMI or stroke before 65 years) and 173 control subjects (with neither AMI nor personal or familial history of arterial thrombosis). All subjects were Italian. Patients showed fibrinogen levels higher than control subjects. There was a highly significant difference in allele frequency in cases versus control subjects, the B2 allele frequencies being respectively 0.28 versus 0.17 (
P
=.002). In multivariate analysis, adjusted for sex, age, smoking habits, and history of hyperlipidemia, hypertension, or diabetes, the (B1B2+B2B2) genotype was associated with a higher risk of AMI (odds ratio 2.4, 95% confidence interval, 1.2 to 4.6). The
Bcl
I genotype was also associated with fibrinogen levels, independently of gender and smoking habits, the (B1B2+B2B2) subjects showing the highest levels in both cases and control subjects. The difference in fibrinogen levels between cases and control subjects was significantly influenced by the genotype (significant interaction,
P
=.042) The B2 allele of the
Bcl
I polymorphism in the β-chain of the fibrinogen gene is a new factor associated with the risk of familial AMI through its association with fibrinogen levels. These data provide evidence for a causal role of fibrinogen in familial AMI.
Thrombin-Induced Thromboxane Synthesis by Human Platelets
Authors: Henriksen Ruth Ann , Samokhin Gennady P. , Tracy Paula B.
Published: June 2011

AbstractThese studies have examined the effects of thrombin-related agonists in stimulating thromboxane production by human platelets. The results presented show that (1) the maximal response elicited by thrombin receptor agonist peptide (TRAP) stimulation was 40% to 50% of that seen with thrombin or the thrombin mutant Thrombin Quick I; (2) pretreatment of platelets with prostaglandin E1or genistein resulted in differential inhibition of thromboxane production in response to TRAP compared with either enzyme agonist; (3) an antibody to the thrombin receptor cleavage site that inhibits increases in intracellular [Ca2+] only partially reduced thromboxane production in response to 5 nmol/L thrombin and 15 nmol/L Thrombin Quick I; (4) preincubation with 20 μmol/L TRAP resulted in desensitization to further stimulation by 100 μmol/L TRAP, but not by 100 nmol/L thrombin; and (5) the response to thrombin after TRAP desensitization was completely inhibited by the tyrosine kinase inhibitor genistein and was independent of an intracellular [Ca2+] flux. The cumulative results may be explained by the existence of two proteolytically activated receptors that result in thromboxane production in response to thrombin. One is the thrombin receptor/substrate, PAR-1. Stimulation through the second receptor/substrate depends on a genistein-sensitive step, is independent of an intracellular Ca2+flux, and is initiated by a thrombin-activated receptor that does not depend on interaction with anion-binding exosite I, as previously indicated by the relative activity of Thrombin Quick I in stimulating platelet aggregation and thromboxane production. The proposed second thrombin receptor on platelets represents an additional member of the class of proteolytically activated receptors.
Adhesiveness of Mononuclear Cells in Hypercholesterolemic Humans Is Normalized by Dietary
l
-Arginine
Authors: Theilmeier Gregor , Chan Jason R. , Zalpour Christoff , Anderson Barbara , Wang Bing-yin , Wolf Andreas , Tsao Philip S. , Cooke John P.
Published: June 2011

Abstract
Hypercholesterolemia reduces vascular nitric oxide (NO) activity. This dysfunction may promote endothelial monocyte interaction, as NO is a potent inhibitor of cell adhesion. We have previously shown that in hypercholesterolemic (HC) rabbits, chronic oral supplementation of
l-
arginine (Arg) restores NO activity and inhibits monocyte–endothelial cell interaction, in association with a reduction in atherogenesis. We hypothesized that enhancement of endothelial NO activity in HC humans would reduce monocyte adhesiveness. We used a functional binding assay to assess the adhesiveness of human mononuclear cells (MNCs) ex vivo to determine the effects of hypercholesterolemia and
l-
arginine administration. MNCs from HC subjects adhered in greater numbers (50% more cells per high-power field;
P
<.0001) than cells derived from normocholesterolemic (NC) subjects. To determine whether enhancement of endogenous NO activity could inhibit mononuclear cell adhesiveness, in a double-blinded placebo-controlled study, oral arginine HCl (8.4 g/d) was administered to HC subjects. Over a course of 2 weeks, this treatment abolished the increased adhesiveness of HC MNCs (160±11% versus 104±5%; before and after 2 weeks of Arg treatment; results expressed as a percentage of the binding values obtained using cells derived from paired NC individuals). By contrast, MNC adhesion remained significantly elevated in placebo-treated HC subjects. To examine whether endothelium-derived NO could act as a paracrine modulator of monocyte behavior, monocytes were exposed to NO donors or cocultured in the presence of endothelial cells exposed to antagonists of NO synthase in the presence or absence of
l-
arginine. NO donors inhibited monocyte adhesiveness. Furthermore, the adhesiveness of monocytes cocultured with endothelial cells was increased by antagonists of NO synthase; this effect was reversed by
l-
arginine. This study shows that the adhesiveness of human MNCs is increased by hypercholesterolemia. The increase in adhesiveness was reversed in vivo by administration of the NO precursor
l-
arginine. NO donors or endothelium-derived NO inhibits the adhesiveness of monocytes in vitro, supporting the hypothesis that the effects of
l-
arginine are mediated by NO.
Shear Stress Inhibits H
2
O
2
-Induced Apoptosis of Human Endothelial Cells by Modulation of the Glutathione Redox Cycle and Nitric Oxide Synthase
Authors: Hermann Corinna , Zeiher Andreas M. , Dimmeler Stefanie
Published: June 2011

Abstract
Physiological levels of shear stress reduce endothelial cell turnover and exert a potent antiatherosclerotic effect. Here we demonstrate that oxidative stress-induced apoptosis of human endothelial cells was inhibited by shear stress exposure (15 dynes/cm
2
). Incubation with H
2
O
2
(200 μmol/L) for 18 hours induced apoptosis of human umbilical venous endothelial cells as demonstrated by an enzyme-linked immunosorbent assay specific for histone-associated DNA fragments and visual analysis of fluorescence-stained nuclei. Shear stress-mediated inhibition of apoptosis was partially prevented by pharmacological inhibition of glutathione (GSH) biosynthesis with buthionine sulfoximine (BSO) or nitric oxide (NO) synthase with
N
G
-monomethyl-
l
-arginine (LNMA), whereas inhibition of catalase by aminotriazol did not affect the inhibitory action of shear stress. Combined inhibition of NO synthase and GSH biosynthesis completely reversed the protective effect of shear stress, suggesting that both NO synthase and the GSH redox cycle system are involved in the apoptosis-suppressing effect of shear stress. Similar results were obtained when apoptosis was stimulated by tumor necrosis factor α (TNFα). To gain further insights into the interference of shear stress with apoptosis signal transduction, we measured caspase-3-like activity, a cysteine protease that has been shown to play a predominant role in the cell death effector pathway. Indeed, shear stress prevented the activation of caspase-3-like activity induced by H
2
O
2
or TNFα. The inhibitory effect of shear stress was prevented by LNMA and BSO, suggesting that the reduction of oxidative flux by shear stress prevents the activation of caspase-like proteases and thereby inhibits apoptotic cell death in human endothelial cells.
Fibroblasts That Overexpress 15-Lipoxygenase Generate Bioactive and Minimally Modified LDL
Authors: Sigari Farhad , Lee Chris , Witztum Joseph L. , Reaven Peter D.
Published: June 2011

AbstractSeveral lines of evidence suggest that the cellular enzyme 15 lipoxygenase (15-LO) may be important in promoting the oxidation of lipoproteins in vivo. In previous studies we have shown that fibroblasts transfected with 15-LO “seed” LDL with lipoperoxides such that subsequent oxidation readily generates an LDL that is taken up by macrophages through scavenger receptors. We now demonstrate that LDL incubated with 15-LO cells is “minimally modified” and has bioactive properties. Characterization of LDL incubated with 15-LO cells reveals that lipid peroxidation is modest, with low levels of TBARS generated (12.6±4.7 nmole MDA per mg protein) and small amounts of 18:2 lost as a result of oxidation (7%, compared with extensive loss [82%] with copper oxidation). The 15-LO–conditioned LDL showed mildly increased electrophoretic mobility on agarose gels, and on polyacrylamide gels it showed only mild protein degradation compared with copper-oxidized LDL. Additionally 15-LO–conditioned LDL competed very well for the LDL receptor of fibroblasts but did not compete for macrophage uptake of125I-acetylated LDL. Importantly, compared with LDL incubated on β-galactosidase (lac Z)–transfected control cells, LDL incubated on 15-LO cells stimulated monocyte chemotaxis (15-LO–LDL, 6.9±1.2 monocytes per field versus lac Z-LDL, 0±0.9 monocytes per field) and when added to endothelial cells enhanced adhesion (15-LO–LDL, 31.1±5.0 monocytes per field versus lac Z–LDL, 0±2.0 monocytes per field). Preincubation of 15-LO cells with 15-LO inhibitors significantly inhibited the generation of bioactive LDL. Lipid extracts of LDL conditioned on 15-LO cells showed chemotactic activity not related to lysophosphatidylcholine levels. Preincubation of target endothelial cells with several different platelet-activating factor receptor antagonists prevented stimulation of monocyte adhesion by 15-LO–conditioned LDL. When probucol- or vitamin E–enriched LDL was incubated with 15-LO cells it was less oxidized and less bioactive, which suggests that these cells seed LDL with LOOH, which then requires further propagation of lipid peroxidation to yield bioactivity. These studies demonstrate that fibroblasts expressing 15-LO reliably produce a bioactive “minimally modified” LDL, which may explain in part how cellular 15-LO activity may generate atherogenic LDL in vivo.
Lipoprotein Lipid Response to the National Cholesterol Education Program Step II Diet by Hypercholesterolemic and Combined Hyperlipidemic Women and Men
Authors: Walden Carolyn E. , Retzlaff Barbara M. , Buck Brenda L. , McCann Barbara S. , Knopp Robert H.
Published: June 2011

The beFIT study tested whether teaching the NCEP step II diet (<30% of calories from total fat and <7% from saturated fat) is an effective therapy in hypercholesterolemic women and men with or without elevated triglycerides after 6 months. Hypercholesterolemic subjects had two LDL cholesterol measurements above the age- and sex-specific 75th percentile, and combined hyperlipidemic subjects additionally had similarly elevated triglyceride. Subjects were randomized to receive dietary intervention (eight weekly classes) immediately or 6 months later. Follow-up visits were quarterly, with lipid measurements and 4-day food records. Subjects randomized to delayed intervention did not report diet changes or experience lipid changes; the immediate intervention group significantly reduced fat and cholesterol intakes, resulting in significant LDL cholesterol lowering. Six months after diet instruction, 178 women and 231 men reported total and saturated fat intakes of ≈25% and 7.5% kcal. LDL cholesterol was significantly reduced in women (7.6% and 8.1%) and men (8.8% and 8.1%) with hypercholesterolemia and combined hyperlipidemia, respectively, but was not different by sex or lipid disorder. Candidates for drug therapy were reduced from between 27% and 37% to 20%. HDL cholesterol was significantly decreased in women (−6.4% and −4.7%) but not in men (−1.3% and −2.7%). The 6.4% reduction in hypercholesterolemic women was significantly different from that of men. The significance of the HDL cholesterol reduction in women is unknown. LDL cholesterol response was similar between women and men and between hypercholesterolemic and combined hyperlipidemic subjects. LDL cholesterol lowering by diet can significantly reduce the number of hyperlipidemic persons requiring drug therapy.
The Effect of Immunodepletion of Antithrombin III on the Response of Rabbits to Russell's Viper Venom–Induced Activation of Factor X
Authors: Rapaport Samuel I. , Toneff Thomas , Rimon Abraham , Warn-Cramer Bonnie J.
Published: June 2011

Many years ago it was shown that an infusion of tissue factor (TF) into rabbits causing only limited consumption of factor X and prothrombin resulted in extensive consumption of fibrinogen. More recently it was shown that an injection of a concentration of the factor X–activating fraction of Russell's viper venom (RVV-X) depleting rabbits of factor X resulted in only minimal consumption of both plasma prothrombin and fibrinogen. We report here experiments in which rabbits depleted of antithrombin III (ATIII) to different degrees were infused over 4 hours with a concentration of RVV-X, causing consumption of about 60% of plasma factor X. Similar minimal mean falls in plasma prothrombin and fibrinogen levels were observed in control rabbits given nonimmune goat IgG and in rabbits immunodepleted with goat anti-rabbit ATIII IgG to about 40% of normal plasma ATIII activity. However, if rabbits were immunodepleted to about 10% to 20% of normal plasma ATIII, then mean consumption of prothrombin was increased modestly and, more impressively, mean consumption of plasma fibrinogen was increased markedly. Whereas limited amounts of thrombin generated on the surface of phospholipid vesicles by factor VIIa/TF can trigger extensive intravascular coagulation in rabbits with normal plasma ATIII levels, limited amounts of thrombin generated by reactions triggered by factor Xa formed in fluid phase did so only after plasma ATIII levels were markedly depleted. A possible reason for this difference is discussed.
Oxidized LDL Mediates the Release of Fibroblast Growth Factor-1
Authors: Ananyeva Natalya M. , Tjurmin Alexey V. , Berliner Judith A. , Chisolm Guy M. , Liau Gene , Winkles Jeffrey A. , Haudenschild Christian C.
Published: June 2011

Abstract
Fibroblast growth factor-1 (FGF-1) and lipoproteins play an important role in atherogenesis. In the present study, we explored a possible mechanism by which abnormal lipid metabolism could be linked to the proliferative aspects of the disease. We tested oxidized LDL (oxLDL) as a possible pathophysiological mediator of the release of FGF-1, using FGF-1–transfected mouse NIH 3T3 cells and FGF-1–transfected rabbit smooth muscle cells, and compared it with the release caused by elevated temperature. Immunoblot analysis showed that oxLDL induced the release of FGF-1 in a concentration-dependent manner from 10 to 100 μg/mL. The effect correlated with the extent of oxidative modification of LDL and was maximal within 4 hours of exposure of cells to oxLDL. In contrast to the temperature stress–induced FGF-1 secretion pathway, FGF-1 released in response to oxLDL (1) appeared in the conditioned medium as a monomer, (2) appeared independently of the presence of either actinomycin D or cycloheximide, and (3) was neither enhanced nor inhibited by brefeldin A. We did not detect cell loss, significant morphological changes, changes in growth characteristics, or other indications of lethal toxicity in oxLDL-treated cells. Although the level of lactate dehydrogenase activity was elevated after oxLDL exposure, the calculations showed that >90% of the FGF-1 was released by viable cells. We propose that oxLDL-induced FGF-1 release is mediated by sublethal and apparently transient changes in cell membrane permeability. In the environment of an atherosclerotic lesion, oxLDL-induced FGF-1 release may be among the mediators of endothelial and smooth muscle cell proliferation.
Heterogeneity at theCETPGene Locus
Authors: Kuivenhoven Jan Albert , de Knijff Peter , Boer Jolanda M.A. , Smalheer Harold A. , Botma Gert-Jan , Seidell Jaap C. , Kastelein John J.P. , Pritchard P. Haydn
Published: June 2011

AbstractThis study was designed to investigate the association(s) between heterogeneity at the cholesteryl ester transfer protein (CETP) gene locus, CETP plasma concentrations, and HDL cholesterol levels. Healthy men with the lowest, median, and highest deciles of HDL cholesterol were selected from a large population database. We accounted for factors that are known to influence HDL cholesterol levels, such as smoking, exercise, body mass index, alcohol consumption, and blood pressure. Plasma CETP concentrations were measured, and we determined the allele frequency distribution of sixCETPDNA polymorphisms. The group with low HDL cholesterol exhibited a significant increase in CETP concentration compared with both the median and high HDL cholesterol groups, whereas CETP concentrations did not differ among the groups with median and high HDL cholesterol. The allele frequency distributions of theTaqIB (intron 1),MspI (intron 8), andRsaI (exon 14) polymorphisms differed significantly between the groups with low and high HDL cholesterol. Further analysis revealed that theMspI polymorphism had a 1.5-fold larger impact on CETP concentration than theTaqIB polymorphism and a fivefold larger impact than theRsaI polymorphism. In conclusion, we demonstrated that heterogeneity at theCETPgene locus is correlated with CETP plasma concentrations and HDL cholesterol levels. More specifically, our data indicate the presence of a strong association between common variants of theCETPgene, high plasma CETP concentrations, and consequently hypoalphalipoproteinemia in healthy white men.
Correlation of a Common Mutation in the Methylenetetrahydrofolate Reductase Gene With Plasma Homocysteine in Patients With Premature Coronary Artery Disease
Authors: Christensen Benedicte , Frosst Phyllis , Lussier-Cacan Suzanne , Selhub Jacob , Goyette Philippe , Rosenblatt David S. , Genest Jacques , Rozen Rima
Published: June 2011

Abstract
Mild hyperhomocysteinemia, a risk factor for occlusive arterial disease, can be caused by disruptions of homocysteine metabolism. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of 5-methyltetrahydrofolate, the methyl donor for homocysteine remethylation to methionine. A common mutation in
MTHFR
, an alanine-to-valine substitution, may contribute to mild hyperhomocysteinemia in coronary artery disease (CAD). To test this hypothesis, we studied 152 patients with CAD by mutation analysis,
MTHFR
enzymatic assays, and measurements of plasma homocysteine and several vitamins. The
MTHFR
mutation was associated with reduced enzymatic activity and increased enzyme thermolability in these patients. The difference in the prevalence of the homozygous mutant genotype between the CAD patients (14%) and an unmatched group of healthy subjects (10%) was not significant. However, individuals with the homozygous mutant genotype had higher plasma homocysteine, particularly when plasma folate was below the median value. This genetic-environmental interaction is proposed to be a risk factor for CAD.
Extent and Composition of Coronary Lesions and Degree of Cardiac Hypertrophy in Relation to Abdominal Fatness in Men Under 40 Years of Age
Authors: Kortelainen Marja-Leena , Särkioja Terttu
Published: June 2011

Abstract
The relationship of the extent and composition of coronary lesions and the degree of cardiac hypertrophy to anthropometric indicators of abdominal fatness and the amount of intra-abdominal fat was investigated in a group of 32 forensic autopsy cases that consisted of sudden deaths from violent causes of previously healthy men under 40 years of age. Body height and weight, waist and hip circumferences, and the thickness of the subscapular and abdominal subcutaneous fat were measured; the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated; and omental, mesenteric, and perirenal fat deposits and the heart were weighed. The degree of coronary narrowing was determined visually, and the extent of coronary lesions was measured by planimetry. The thickness of the intima and intima-media was measured by computerized image analysis. Intimal macrophage foam cells and smooth muscle cells were detected by immunohistochemistry. Significant positive correlations were found between WHR and the overall degree of coronary narrowing and the intima-media thicknesses of the left anterior descending artery and right coronary artery when adjusted for age. Intima-media thickness was also related to tertiles of WHR. Heart weight indexed to height
2.7
showed a significant positive correlation with BMI, waist circumference, WHR, and the size of intra-abdominal fat deposits, of which WHR was the best predictor of mild cardiac hypertrophy. The results indicate that the severity of clinically silent lesions in the atherosclerosis-prone regions of the coronary arteries is associated with WHR in young male individuals who also have mild myocardial hypertrophy associated with abdominal fatness and an accumulation of intra-abdominal fat. These associations between fat distribution and early cardiovascular changes point to a powerful need for preventive action with respect to weight gain in young men to alleviate progression of the lesions.
Differentiation of Smooth Muscle Cells in Human Blood Vessels as Defined by Smoothelin, a Novel Marker for the Contractile Phenotype
Authors: van der Loop Frank T. L. , Gabbiani Giulio , Kohnen Gaby , Ramaekers Frans C. S. , van Eys Guillaume J. J. M.
Published: June 2011

Abstract
Smoothelin is a constituent of the cytoskeleton specific for smooth muscle cells (SMCs) in a broad range of species. It has been postulated that smoothelin represents a marker of highly differentiated, contractile SMCs. Here, we present data on the presence of smoothelin in the human vascular system that support this hypothesis. For this purpose, smoothelin distribution was studied (1) during vasculogenesis of the placenta, (2) in normal adult blood vessels, and (3) in atherosclerotic lesions. Smoothelin was first observed in placental tissue at approximately week 10 to 11 of gestation. In full-term placenta, it was found in the SMCs of vessels in the large stem villi and in the chorionic plate. Furthermore, it was present in the fetal arteries of smaller stem villi, but it was not found in the veins. In adult blood vessels, a small population of aortic (≈10%) and large muscular artery (≈30% to 50%) SMCs was positive for smoothelin. In general, smoothelin and desmin were coexpressed in the same SMCs, but expression of desmin appeared to be less abundant. However, the majority of SMCs in these blood vessels were smoothelin- and desmin-negative but expressed vimentin, whereas α-smooth muscle actin (α-SMA) was present in all SMCs. The SMCs in the media of small muscular arteries were positive for smoothelin and desmin (>95%), whereas the vimentin-positive SMC type was scarce. Smoothelin was absent in capillaries, pericytic venules, and small veins but was occasionally observed in the SMCs of large veins. Thus, the distribution of smoothelin in the SMCs of the vascular system appears to be limited to blood vessels that are capable of pulsatile contraction. In atherosclerotic femoral arteries, smoothelin-positive cells were detected in the media, the atheromatous plaque, and the intimal thickening. Smoothelin-positive cells were present primarily at the luminal portion of advanced lesions. The presence of a considerable number of such smoothelin-positive cells at that location may indicate that these plaques are no longer expanding.
Dietary Fish Oil
Authors: Barbeau Michele L. , Klemp Keith F. , Guyton John R. , Rogers Kem A.
Published: June 2011

Abstract
We examined the influence of dietary fish oil on lesion regression in a porcine model of atherogenesis. Thirty-two female Yucatan miniature pigs were fed an atherogenic diet for 8 months. A no-regression group (n=8) was killed to determine the extent of atherosclerosis at 8 months. Three regression groups were switched to normal minipig chow supplemented with either MaxEPA fish oil (FO group, n=8), a control oil with the ratio of polyunsaturated to monounsaturated to saturated fatty acid matched to that of the fish oil (CO group, n=8), or no oil supplement (NO group, n=8) for a further 4 months. Plasma cholesterol levels reached between 15 and 20 mmol/L during the atherogenic phase and returned to normal (2 mmol/L) within 2 months of the beginning of the regression diet. Compared with the NO group, fish oil supplementation during the regression phase caused a decrease in VLDL and HDL cholesterol and an increase in LDL cholesterol. Similarly, the control oil also caused a decrease in VLDL cholesterol; however, in contrast to the FO group, HDL cholesterol increased and LDL cholesterol was unchanged. FO LDL, which had decreased levels of 20:4 (n-6 fatty acid) and increased levels of 18:3, 20:5, and 22:6 (n-3 fatty acids), was shown to be twice as susceptible to copper-mediated oxidation as CO LDL particles. Morphological examination of the major blood vessels revealed a significant reduction in lesion area in the ascending and thoracic aorta as well as the carotid artery after the regression diet; however, there was no significant difference between the fish oil and control oil groups in any of the vessels measured. Therefore, despite increased LDL, decreased HDL, and an increased susceptibility to in vitro oxidation of LDL, fish oil supplementation of a regression diet did not influence lesion regression.
Natriuretic Peptide Family as a Novel Antimigration Factor of Vascular Smooth Muscle Cells
Authors: Ikeda Miwako , Kohno Masakazu , Yasunari Kenichi , Yokokawa Koji , Horio Takeshi , Ueda Makiko , Morisaki Nobuhiro , Yoshikawa Junichi
Published: June 2011

Abstract
Vascular smooth muscle cell (SMC) migration is proposed to be an important process in the initiation and/or progression of atherosclerosis. The present study examined the effects of the natriuretic peptide family (atrial, brain, and C-type natriuretic peptides; ANP, BNP, and CNP) on the migration of cultured rat SMCs, using Boyden's chamber methods. Fetal calf serum (FCS) and platelet-derived growth factor (PDGF)-BB potently stimulated SMC migration. Rat ANP(1-28), rat BNP-45, and rat CNP-22 clearly inhibited SMC migration stimulated with FCS or PDGF-BB in a concentration-dependent manner. CNP-22 had the most potent inhibitory effect compared with other natriuretic peptides. When PDGF-BB–induced migration was separated into chemotactic and chemokinetic activities, the chemotactic component was strongly inhibited by these natriuretic peptides. Such inhibition by these natriuretic peptides was paralleled by an increase in the cellular level of cyclic GMP. The addition of a cyclic GMP analogue, 8-bromo cyclic GMP, and an activator of the cytosolic guanylate cyclase, sodium nitroprusside, significantly inhibited FCS- and PDGF-BB–stimulated migration in a concentration-dependent manner. These results suggest that natriuretic peptides, especially CNP-22, inhibit FCS- or PDGF-BB–stimulated SMC migration at least in part through a cyclic GMP–dependent process. Thus, the natriuretic peptide family may play a role as an antimigration factor of SMCs under certain circumstances.
The Effect of Oxidizing Cholesterol on Gastrointestinal Absorption, Plasma Clearance, Tissue Distribution, and Processing by Endothelial Cells
Authors: Krut Louis H. , Yang Joseph W. , Schonfeld Gustav , Ostlund, Jr Richard E.
Published: June 2011

Abstract
Little is known about the absorption or metabolism of oxysterols. Toward better appreciating the metabolic consequences of oxidizing cholesterol, we compared labeled cholesterol with the labeled oxysterols 7α-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol prepared from [4-
14
C]cholesterol, [26,26,26,27,27,27-
2
H
6
]cholesterol, and [23,24,25,26,27-
13
C
5
]cholesterol. Gastrointestinal absorption of oxysterols in rats was 91.5±0.3% compared with 75±1.1% for cholesterol, determined by fecal collection (
P
<.001). When injected intravenously and followed by gas chromatography/mass spectrometry, 7α-hydroxycholesterol was cleared at 23 times the rate of cholesterol. After 5 minutes, only 1.2±0.2% of 7α-hydroxycholesterol remained in the plasma, whereas 28.0±1.7% of cholesterol and 40.0±2.5% of a triglyceride emulsion injected simultaneously were still present. [
14
C]7α-Hydroxycholesterol injected intravenously was also rapidly cleared from plasma, was widely distributed in tissues and organs, and showed evidence of extensive metabolism at 5 minutes. The fractional rate of uptake of radiolabeled oxysterols by cultured endothelial cells was 15.7 times that of cholesterol (
P
<.001), and the fractional rate of efflux was 3.4 times that of cholesterol (
P
<.001). Oxysterols passed through endothelial cells grown on transwell membranes at a rate 4.3 times that of cholesterol (
P
<.001). Fractional oxysterol transport across the endothelial cell monolayer was increased 62±17% when HDL was added to the medium in the lower chamber (
P
=.003). Oxysterols were extensively metabolized to even more polar metabolites during endothelial cell transit. These properties of oxysterols potentially provide a mechanism for enhancing transport of cholesterol through tissues and preventing accumulation of cholesterol in those cells that can oxidize it.
Inhibition of Proliferation and Stimulation of Migration of Endothelial Cells by Secretoneurin In Vitro
Authors: Kähler Christian M. , Kirchmair Rudolf , Kaufmann Gerhard , Kähler Stefan T. , Reinisch Norbert , Fischer-Colbrie Reiner , Hogue-Angeletti Ruth , Winkler Hans , Wiedermann Christian J.
Published: June 2011

AbstractVascular cell responses in inflammation are affected by several neuropeptides of perivascular nerve fibers. Secretoneurin is a 33–amino acid peptide that is coreleased from these nerve endings with other proinflammatory neuropeptides, eg, substance P and calcitonin gene–related peptide. Furthermore, secretoneurin has been shown to be chemotactic for human skin fibroblasts and human blood monocytes in vitro and in vivo. An action on cellular components of the vascular wall is not yet reported. We therefore investigated in vitro effects of this novel sensory neuropeptide on endothelial cells. Secretoneurin exerted a potent and reversible inhibitory effect both on endothelial cell growth under low serum conditions (1% fetal calf serum) and endothelial cell growth factor–activated endothelial cell proliferation. We show in the present study that secretoneurin exerts this effect on aortic (rat) and pulmonary artery (bovine) endothelial cells, as well as venous (human umbilical vein) endothelium. Endothelial cell chemotaxis was tested by means of three different migration assays employing nitrocellulose and polycarbonate micropore filters. Secretoneurin consistently exhibited potent chemoattractant activity. The effective concentrations for the observed effects were in the picomolar range. The combination of chemotactic and antiproliferative effects on endothelial cells suggests that secretoneurin may act as a regulatory factor of vascular cell functions.
Cellular Radiosensitivity, Radioresistant DNA Synthesis, and Defect in Radioinduction of p
53
in Fibroblasts From Atherosclerosis Patients
Authors: Nasrin Nargis , Mimish Layth A. , Manogaran Pulicat S. , Kunhi Mohammed , Sigut David , Al-Sedairy Sultan , Hannan Mohammed A.
Published: June 2011

Abstract
Earlier studies have suggested that both cancer and atherosclerosis may follow a common pathway in the early stage of development and share certain risk factors. One report indicated that the gene responsible for the radiosensitive, cancer-prone, multisystem disorder ataxia telangiectasia (AT) may increase the risk of developing ischemic heart disease. The present studies were carried out to find similarities, if any, between atherosclerosis patients and AT homozygotes or heterozygotes (ATHs) in their cellular/molecular response to ionizing radiation, which acts as a carcinogen as well as an atherogen. Fibroblast cell strains developed from healthy subjects and from AT homozygotes, ATHs, and atherosclerosis patients were compared for (1) survival, by the colony-forming assay and (2) DNA synthesis inhibition after irradiation, determined by [
3
H]thymidine incorporation, cell cycle distribution, and the expression of p
53
and p
21
proteins, analyzed by flow cytometry. Fibroblasts from the atherosclerosis patients as a group, compared with the healthy subjects, showed enhanced sensitivity to chronic (low-dose-rate) irradiation. A majority of the cell strains representing atherosclerosis patients exhibited varying degrees of radioresistant DNA synthesis (RDS), with roughly 33% showing an AT-like and the rest an ATH-like response. All cell strains with an AT-like and one quarter with an ATH-like RDS were found to be defective in the radioinduction of both p
53
and p
21
proteins, which are concerned with cell cycle regulation. An absence of G
1
arrest after irradiation was observed in cell strains lacking a radioinduced expression of p
53
and p
21
. Cellular/ molecular defects leading to increased radiosensitivity, reduced induction of p
53
/p
21
, and cell cycle deregulation found to be associated with cancer-prone disorders such as AT may constitute important risk factors for atherosclerosis as well.
Genetic Cholesteryl Ester Transfer Protein Deficiency Is Extremely Frequent in the Omagari Area of Japan
Authors: Hirano Ken-ichi , Yamashita Shizuya , Nakajima Norimichi , Arai Takeshi , Maruyama Takao , Yoshida Yu , Ishigami Masato , Sakai Naohiko , Kameda-Takemura Kaoru , Matsuzawa Yuji
Published: June 2011

Abstract
Low levels of HDL cholesterol have been clearly demonstrated to be associated with an increased incidence of coronary heart disease, strongly suggesting that HDL particles have an antiatherogenic function. However, little information has been available concerning the atherogenicity of a marked hyperalphalipoproteinemia (HALP). There is no agreement about whether plasma cholesteryl ester transfer protein (CETP) deficiency is associated with an antiatherogenic state or not, although this disorder was reported to be one of the major causes of marked HALP. In the current study, we have found a unique area (Omagari City, Akita Prefecture, Japan) where CETP deficiency caused by a G-to-A mutation at the 5′ splice donor site of intron 14 in the CETP gene is extremely frequent. In Omagari City, the mutation was detected more than 20 times more frequently and the prevalence of a marked HALP with plasma HDL cholesterol ≥2.58 mmol/L (100 mg/dL) was 5 to 10 times higher than in other areas of Japan. This discovery has made it possible to perform a large population-based study concerning the atherogenicity of a marked elevation of HDL cholesterol in a genetically more homogeneous population. There was a statistically significant U-shaped relationship between HDL cholesterol levels and the incidence of ischemic changes in electrocardiograms. In cases of HDL cholesterol <1.81 mmol/L (70 mg/dL), the incidence increased in proportion to the levels of HDL cholesterol. The frequency of the CETP gene mutation was higher in patients with coronary heart disease than in healthy control subjects. In subjects aged >80 years, the prevalence of both marked HALP and the intron 14 splicing defect was significantly lower than in the younger generation. The current study indicated for the first time that a marked HALP caused by CETP gene mutation may not represent a longevity syndrome, suggesting the importance of reevaluation of the clinical significance and pathophysiology of a marked HALP.
The Effects of Folic Acid Supplementation on Plasma Total Homocysteine Are Modulated by Multivitamin Use and Methylenetetrahydrofolate Reductase Genotypes
Authors: Malinow M.R. , Nieto F.J. , Kruger W.D. , Duell P.B. , Hess D.L. , Gluckman R.A. , Block P.C. , Holzgang C.R. , Anderson P.H. , Seltzer D. , Upson B. , Lin Q.R.
Published: June 2011

Abstract
Elevated concentration of plasma total homocysteine (tHcy) is a common risk factor for arterial occlusive diseases. Folic acid (FA) supplementation usually lowers tHcy levels, but initial tHcy and vitamin levels, multivitamin use, and polymorphisms in the gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) may contribute to variability in reduction. We tested the effects of a 3-week daily intake of 1 or 2 mg of FA supplements on tHcy levels in patients with and without coronary heart disease (CHD) who were analyzed for the C677T MTHFR mutation. Prior multivitamin intake and baseline vitamin and tHcy levels were also compared with responsiveness to folate supplementation. Both dosages of FA lowered tHcy levels similarly, regardless of sex, age, CHD status, body mass index, smoking, or plasma creatinine concentration. In non–multivitamin users, FA supplements reduced tHcy by 7% in C/C homozygotes and by 13% or 21% in subjects with one or two copies of the T677 allele, respectively; the corresponding reductions were smaller in users of multivitamins. Moreover, T/T homozygotes had elevated tHcy and increased susceptibility to high levels of tHcy at marginally low plasma folate levels, as well as enhanced response to the tHcy-lowering effects of FA. Although other factors are probably involved in the responsiveness of tHcy levels to FA supplementation, about one third of heterogeneity in responsiveness was attributable to baseline tHcy and folate levels and to multivitamin use.