bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Smoking Causes Nitroglycerin Resistance in Platelets by Depletion of Intraplatelet Glutathione
Authors: Haramaki Nobuya , Ikeda Hisao , Takajo Yoshinori , Katoh Atsushi , Kanaya Seiji , Shintani Satoshi , Haramaki Reiko , Murohara Toyoaki , Imaizumi Tsutomu
Published: September 2007

We investigated whether platelet responsiveness to nitroglycerin (NTG) is maintained in long-term smokers and if not, the mechanism. In the absence or presence of NTG, intraplatelet reduced glutathione (GSH) levels and ADP-induced platelet aggregation and intraplatelet cGMP levels were measured in 10 long-term smokers and 10 age-matched nonsmokers. The intraplatelet GSH level was significantly lower in smokers than in nonsmokers (
P
<0.05). Platelet aggregation was dose-dependently inhibited by NTG in both groups; however, inhibition was significantly weaker in smokers.
N
-acetylcysteine (1 mmol/L), an exogenous thiol agent, significantly potentiated NTG-induced platelet inhibition in nonsmokers but not in smokers. The ADP-induced intraplatelet cGMP level was significantly greater in the presence of NTG in nonsmokers but not so in smokers. Because the effects of long-term smoking are multifactorial, a rabbit model was made by chronic administration of buthionine sulfoximine (BSO, n=6) to decrease intraplatelet GSH. The intraplatelet GSH level was significantly lower in BSO-treated rabbits than in saline-treated rabbits (
P
<0.001). The NTG-induced inhibition of platelet aggregation was significantly weaker in BSO rabbits.
N
-acetylcysteine–induced potentiation was not observed in BSO rabbits, whereas significant potentiation was found in saline rabbits. These findings were similar to those of long-term smokers. In contrast, the intraplatelet GSH-to–oxidized glutathione ratio, which represents the redox state of glutathione, was significantly lower in smokers than in nonsmokers, whereas no difference was found between saline rabbits and BSO rabbits. In conclusion, long-term smoking causes NTG resistance to aggregation in platelets, possibly through the depletion of intraplatelet GSH.
Increased Transcription of IL-8 in Endothelial Cells Is Differentially Regulated by TNF-α and Oxidized Phospholipids
Authors: Yeh Michael , Leitinger Norbert , de Martin Rainer , Onai Nobuyuki , Matsushima Kouji , Vora Devendra K. , Berliner Judith A. , Reddy Srinivasa T.
Published: September 2007

Oxidized 1-palmitoyl-2-arachidonoyl-
sn
-glycero-3-phosphorylcholine (Ox-PAPC) upregulates a spectrum of inflammatory cytokines and adhesion molecules different from those induced by classic inflammatory mediators such as tumor necrosis factor-α (TNF-α) or lipopolysaccharide. Interestingly, Ox-PAPC also induces the expression of a set of proteins similar to those induced by TNF-α or lipopolysaccharide, which include the chemokines monocyte chemotactic protein-1 (MCP-1) and interleukin (IL)-8. To elucidate the molecular mechanisms of Ox-PAPC-induced gene expression and to determine whether Ox-PAPC and other inflammatory mediators such as TNF-α utilize common signaling pathways, we examined the transcriptional regulation of IL-8 by Ox-PAPC and TNF-α in human aortic endothelial cells. Both Ox-PAPC and TNF-α induced the expression of IL-8 mRNA in a dose-dependent fashion; however, the kinetics of IL-8 mRNA accumulation between the 2 ligands differed. Ox-PAPC-induced IL-8 mRNA was seen as early as 30 minutes, peaked between 4 and 8 hours, and decreased substantially by 24 hours. In contrast, TNF-α-induced IL-8 mRNA synthesis was elevated at 30 minutes, peaked at 2 hours, and reached basal/undetectable levels by 6 hours. Actinomycin D experiments suggested that both Ox-PAPC and TNF-α regulate the expression of IL-8 at the transcriptional level. Furthermore, the half-life of IL-8 mRNA for both ligands was similar (<30 minutes), suggesting that mRNA stability was not responsible for the differences in the kinetics of IL-8 accumulation between the 2 ligands. Transient transfection studies with reporter constructs containing 1.48 kb of the IL-8 promoter identified an Ox-PAPC-specific response region between −133 and −1481 bp of the IL-8 promoter. In contrast, TNF-α activation of the IL-8 promoter was mediated almost entirely through the nuclear factor-κB and activation protein-1 response elements present between −70 and −133 bp of the IL-8 promoter. Thus, although Ox-PAPC and TNF-α both induced IL-8 synthesis, our data suggest that the 2 ligands utilize different mechanisms in the regulation of IL-8 transcription.
Phosphatidylinositol 3-OH Kinase–Akt/Protein Kinase B Pathway Mediates Gas6 Induction of Scavenger Receptor A in Immortalized Human Vascular Smooth Muscle Cell Line
Authors: Ming Cao Wen , Murao Koji , Imachi Hitomi , Sato Makoto , Nakano Toru , Kodama Tatsuhiko , Sasaguri Yasuyuki , Wong Norman C.W. , Takahara Jiro , Ishida Toshihiko
Published: September 2007

The growth arrest–specific gene 6 encodes a secreted protein, Gas6, which was originally identified as the ligand of a receptor, Axl, with tyrosine kinase activity. The class A scavenger receptor (SRA) mediates lipid uptake into cells, leading to the formation of foam cells, an important step in atherogenesis. Although Gas6 induces SRA expression, the underlying mechanism is not clear. In this report, we show that the Gas6-induced expression of SRA was mediated by the phosphatidylinositol 3-OH kinase (PI3-kinase)–serine/threonine kinase (Akt/protein kinase B [PKB]) pathway involving Akt phosphorylation. This pathway was activated by exposure to Gas6. Furthermore, the effect of Gas6 was abrogated by wortmannin, a specific inhibitor of PI3-kinase. We also demonstrated that the constitutively active form of Akt enhanced activity of the SRA promoter but that the dominant-negative mutant of Akt completely abolished the expression of SRA after treatment with Gas6. These results show that the PI3-kinase–Akt/PKB pathway participates in Gas6-induced SRA expression and suggests that the activation of Akt/PKB plays an important role in Gas6-induced atherosclerosis and foam cell formation in human vascular smooth muscle cells.
Chronic Blockade of Endothelin Receptors Improves Ischemia-Induced Angiogenesis in Rat Hindlimbs Through Activation of Vascular Endothelial Growth Factor–NO Pathway
Authors: Iglarz Marc , Silvestre Jean-Sébastien , Duriez Micheline , Henrion Daniel , Lévy Bernard I.
Published: September 2007

This study investigated in vivo the putative angiogenic role of endothelin (ET)-1 in a model of ischemia-induced angiogenesis. Ischemia was produced by unilateral femoral artery occlusion in Wistar rats submitted to either chronic ET-1 infusion (2 nmol · kg
−1
· min
−1
) or to a dual ET
A
/ET
B
receptor antagonist (bosentan, 100 mg · kg
−1
· d
−1
) for 3 and 28 days. Arterial density was evaluated by microangiography and measurement of capillary and arteriolar density in hindlimb muscles. ET-1 infusion had no effect on ischemia-induced angiogenesis and was associated with a slight decrease in vascular endothelial growth factor (VEGF) content measured by Western blot analysis. Conversely, bosentan induced a marked increase in vessel density at 3 and 28 days (1.4-fold and 1.7-fold, respectively, compared with no treatment;
P
<0.05), which was associated with an increase in VEGF and endothelial NO synthase levels in ischemic legs (by 31±8% and 45±23%, respectively, at 3 days and by 65±13% and 55±15%, respectively, at 28 days;
P
<0.05 versus nontreated rats). At day 28, the proangiogenic effect of bosentan was abolished when NO synthesis inhibitor
N
G
-nitro-
l
-arginine methyl ester (10 mg · kg
−1
· d
−1
) or VEGF-neutralizing antibody (2.5 μg/kg twice a week) were coadministered with bosentan. Those results provide the first evidence of an early and sustained proangiogenic effect of endothelin antagonism associated with an upregulation of VEGF and endothelial NO synthase in vivo.
Pulsatile Flow Regulates Monocyte Adhesion to Oxidized Lipid-Induced Endothelial Cells
Authors: Hsiai Tzung K. , Cho Sung K. , Reddy Srinivasa , Hama Susan , Navab Mohamad , Demer Linda L. , Honda Henry M. , Ho Chih M.
Published: September 2007

Oxidized 1-palmitoyl-2-arachidonoyl-
sn
-glycero-3-phosphorylcholine (ox-PAPC), a component of minimally modified low density lipoprotein, induces monocyte adhesion to endothelial cells. It is not known whether the upstroke slopes of pulsatile flow, defined as shear stress slew rates (∂τ/∂t), can regulate monocyte binding to ox-PAPC-treated bovine aortic endothelial cells (BAECs). At 60 cycles per minute, ox-PAPC-treated BAECs were exposed to 3 conditions representing known vascular conditions: (1) high shear stress slew rate (∂τ/∂t=293 dyne · cm
−2
· s
−1
), with time-averaged shear stress=50 dyne/cm
2
; (2) low shear stress slew rate (∂τ/∂t=71 dyne · cm
−2
· s
−1
), with identical time-averaged shear stress; and (3) reversing oscillating flow (0±2.6 mm Hg). Reverse transcription-polymerase chain reaction and quantification were performed for monocyte chemoattractant protein-1 (MCP-1) mRNA expression. High ∂τ/∂t reduced monocyte binding to ox-PAPC-treated BAECs by 64±3.2% compared with static conditions, and low ∂τ/∂t reduced monocyte binding by 31±3.4%, whereas oscillating flow increased monocyte binding by 22±1.7% (
P
<0.005). High ∂τ/∂t downregulated MCP-1 expression by 33±8%, and low ∂τ/∂t downregulated MCP-1 expression by 15±4%, but oscillating flow upregulated MCP-1 by 13±5%. These results suggest that shear stress slew rates regulate monocyte binding by modulating the expression of a potent monocyte chemoattractant.
Effects of Prolonged Intensive Lipid-Lowering Therapy on the Characteristics of Carotid Atherosclerotic Plaques In Vivo by MRI
Authors: Zhao Xue-Qiao , Yuan Chun , Hatsukami Thomas S. , Frechette Ellen Huss , Kang Xiao-Jian , Maravilla Kenneth R. , Brown B. Greg
Published: September 2007

High-resolution magnetic resonance imaging (MRI) with flow suppression not only provides useful information on luminal and wall areas of the carotid artery but also can identify the principal tissue components of the carotid atherosclerotic plaque. The effects of intensive lipid-lowering therapy on these MRI tissue characteristics were examined in patients with coronary disease (CAD). Eight CAD patients who have been receiving intensive lipid-lowering treatment (niacin 2.5 g/d, lovastatin 40 mg/d, and colestipol 20 g/d) for 10 years in the Familial Atherosclerosis Treatment Study (FATS) follow-up were randomly selected from among 60 such treated patients. Eight CAD patients who were matched to the treated patients for age (±3 years), baseline low density lipoprotein (±5 mg/dL), and triglycerides (±50 mg/dL) but who had never been treated with lipid-lowering drugs were selected as controls. For each of these 32 carotid arteries, luminal and plaque areas were measured by planimetry, in a blinded protocol, from the magnetic resonance image that showed most plaque. Fibrous tissue, calcium, and lipid deposits were identified on the basis of established criteria. Plaque composition was estimated as a fraction of total planimetered area. Patients treated with 10-year intensive lipid-lowering therapy, compared with control subjects, had significantly lower low density lipoprotein cholesterol levels (84 versus 158 mg/dL, respectively;
P
<0.001) and higher high density lipoprotein cholesterol levels (51 versus 37 mg/dL, respectively;
P
<0.001). As a group, treated patients, compared with untreated control subjects, had a smaller core lipid area (0.7 versus 10.2 mm
2
, respectively;
P
=0.01) and lipid composition (1% versus 17%, respectively). Group differences in luminal area (55 [treated] versus 44 [control] mm
2
,
P
=NS) and plaque area (58 [treated] versus 64 [control] mm
2
,
P
=NS) tended to favor treatment. MRI appears useful for estimating carotid plaque size and composition. Hyperlipidemic CAD patients frequently (97%) have at least moderate (≥40% area stenosis) carotid plaque. In this case-control study, prolonged intensive lipid-lowering therapy is associated with a markedly decreased lipid content, a characteristic of clinically stable plaques.
Genetic Control of Coordinated Changes in HDL and LDL Size Phenotypes
Authors: Rainwater David L. , Martin Lisa J. , Comuzzie Anthony G.
Published: September 2007

We investigated the correlation of high density lipoprotein (HDL) and low density lipoprotein (LDL) particle size distributions in samples from >1100 participants in the San Antonio Family Heart Study. By use of analyses of individual correlations of each HDL fraction with each LDL fraction, we devised new metrics for particle size phenotype, termed ΔHDL and ΔLDL, to optimally reflect the size correlations. Confirming previous studies, we found that the 2 size phenotype variables were positively correlated (
r
=0.51). Quantitative genetic analysis indicated that nearly half (44%) of the variance in ΔHDL and in ΔLDL was explained by the additive effects of genes. Bivariate genetic analyses indicated that a positive genetic correlation (ρ
G
=0.56) exists between them and suggested that the pleiotropic effects of a gene or group of genes account for ≈31% [ie, ρ
G
2
=(0.56)
2
=0.31] of the genetic variance in the 2 traits. Triglyceride (TG) levels were negatively related to ΔHDL and ΔLDL, with phenotypic correlations of −0.48 and −0.58, respectively, and genetic correlations of −0.45 and −0.76, respectively, suggesting that genes exert significant pleiotropic effects on the covariation of TGs with each of the size variables. Finally, we evaluated a bivariate model for ΔHDL and ΔLDL in which TG level was included as a covariate. This analysis indicated that a small but significant genetic correlation remains for ΔHDL and ΔLDL, even after accounting for the effects of TGs. Thus, our study demonstrates that the phenotypic correlation of HDL and LDL sizes results in part from the pleiotropic actions of a set of genes, some of which also influence TG levels and some of which do not.
Increased Cholesterol Efflux in Apolipoprotein AI (ApoAI)–Producing Macrophages as a Mechanism for Reduced Atherosclerosis in ApoAI
(−/−)
Mice
Authors: Major Amy S. , Dove Dwayne E. , Ishiguro Hiroyuki , Su Yan Ru , Brown Abigail M. , Liu Lily , Carter Kathy J. , Linton MacRae F. , Fazio Sergio
Published: September 2007

The concentration of apolipoprotein (apo) AI in the artery wall is thought to enhance cellular cholesterol efflux and protect against atherosclerosis. It has been shown that although macrophages do not make apoAI, they respond to it by increased cholesterol efflux. We hypothesized that macrophage production of apoAI would increase cholesterol efflux and reduce atherogenesis. In this study, we produced mice expressing human apoAI under the control of the macrophage-specific scavenger receptor-A promoter (mφ-AI). Human apoAI was detectable in the serum HDL fraction of mφ-AI transgenic mice at concentrations too low to affect serum cholesterol or HDL levels. Immunoblotting showed the presence of human apoAI in transgenic macrophage culture supernatants, mostly as lipoprotein-free protein, with a small component associated with HDL-like particles. Atherosclerosis studies using apoAI
(−/−)
mice transplanted with mφ-AI bone marrow showed that in the absence of macrophage-derived apoE, local expression of apoAI reduced diet-induced lesions in the proximal aorta. Additionally, mφ-AI macrophages showed a 40% increase in cholesterol efflux compared with control macrophages. These data support the hypothesis that apoAI production by macrophages in the artery wall is protective against atherosclerosis. This protection is likely mediated by increased cholesterol efflux and decreased foam cell formation in vivo.
Relationship of Periodontal Disease to Carotid Artery Intima-Media Wall Thickness
Authors: Beck James D. , Elter John R. , Heiss Gerardo , Couper David , Mauriello Sally M. , Offenbacher Steven
Published: September 2007

Periodontitis has been linked to clinical cardiovascular disease but not to subclinical atherosclerosis. The purpose of this study was to determine whether periodontitis is associated with carotid artery intima-media wall thickness (IMT). Cross-sectional data on 6017 persons aged 52 to 75 years were obtained from the Atherosclerosis Risk in Communities Study 1996 to 1998 examination. The dependent variable was carotid IMT ≥1 mm. Periodontitis was defined by extent of attachment loss ≥3 mm: none/mild (<10%), moderate (10% to <30%), or severe (≥30%). Covariates included age, sex, diabetes, LDL cholesterol, HDL cholesterol, triglycerides, hypertension, smoking, waist-hip ratio, education, and race/study center. Odds of IMT ≥1 mm were higher for severe periodontitis (OR 2.09, 95% CI 1.73 to 2.53) and moderate periodontitis (OR 1.40, CI 1.17 to 1.67) compared with no periodontitis. In a multivariable logistic regression model, severe periodontitis (OR 1.31, CI 1.03 to 1.66) was associated with IMT ≥1 mm, while adjusting for the other factors in the model. These results provide the first indication that periodontitis may play a role in the pathogenesis of atheroma formation, as well as in cardiovascular events.
In Vivo Complex Formation of Oxidized α
1
-Antitrypsin and LDL
Authors: Mashiba Shinichi , Wada Youichiro , Takeya Motohiro , Sugiyama Akira , Hamakubo Takao , Nakamura Akio , Noguchi Noriko , Niki Etsuo , Izumi Akashi , Kobayashi Mika , Uchida Kazuo , Kodama Tatsuhiko
Published: September 2007

An inactivated form of α
1
-antitrypsin (AT) and LDL coelutes in gel permeation chromatography. To characterize and to quantify the amount of this fraction of AT, a monoclonal antibody was established against chloramine T–oxidized AT and named OxAT-4. OxAT-4 recognized the oxidatively modified AT, including hexylaldehyde- or 4-hydroxy-2-nonenal–modified AT, but neither normal active AT nor trypsin/AT complex. Comigration of apoB and oxidized AT was demonstrated by Western blotting analysis of AT-LDL by means of anti-apoB monoclonal antibody and OxAT-4. A complex of oxidized AT and LDL (AT-LDL) was isolated from human plasma LDL by affinity column with an OxAT-4 antibody–coated carrier. AT-LDL was degraded 4 times more effectively by mouse peritoneal macrophages, but this was not mediated by scavenger receptor class A type I. Localization of AT-LDL was detected in human atherosclerotic lesions of the coronary artery, but distribution of it was not completely identical to that of macrophages. In situ hybridization revealed AT expression by macrophages, which were present in intimal layers of the coronary artery. From these findings, we concluded that AT is produced and oxidized by macrophages, then attached to LDL in the intimal layer of the arterial wall. Although AT-LDL that escapes into the blood stream can be cleared by hepatocytes, the remaining AT-LDL may be taken up by macrophages and contribute to the lipid accumulation in arterial wall cells as the early stage of atherogenesis.
Inclusion of the E3 Region in an Adenoviral Vector Decreases Inflammation and Neointima Formation After Arterial Gene Transfer
Authors: Wen Shan , Driscoll Robert M. , Schneider Darren B. , Dichek David A.
Published: September 2007

Adenoviral vectors are promising agents for vascular gene transfer. Their use, however, is limited by inflammatory host responses, neointima formation, and brevity of transgene expression. Inclusion of the immunomodulatory adenoviral E3 genes in a vector might prevent inflammation and neointima formation and prolong transgene expression. We compared 2 adenoviral vectors in a model of in vivo gene transfer to rabbit arteries. Both vectors expressed a luciferase reporter gene. One vector (AdE3Luc) contained the adenovirus early 3 (E3) region and the other (AdRSVLuc) lacked E3. Expression of E3 genes by AdE3Luc was confirmed in vitro and in vivo. Arteries transduced with AdE3Luc had substantially and significantly less inflammation (fewer T cells and lower levels of vascular cell adhesion molecule-1 and intercellular adhesion molecule 1 expression) and decreased neointima formation 14 days after gene transfer. Luciferase expression from the 2 vectors was equivalent, however, at both 3 and 14 days after gene transfer. Expression of E3 had no systemic immunosuppressive effects, as measured by peripheral blood counts and by assays for serum antibodies to adenovirus. We conclude that expression of E3 significantly decreases adenovirus-induced arterial wall inflammation and neointima formation. Because inflammation and neointima formation are major barriers to the clinical application of adenoviral vectors, use of E3-containing vectors improves the promise of adenovirus-mediated arterial gene transfer.
Localization of c-Myb and Induction of Apoptosis by Antisense Oligonucleotide c-
myb
After Angioplasty of Porcine Coronary Arteries
Authors: Lambert D.L. , Malik N. , Shepherd L. , Gunn J. , Francis S.E. , King A. , Crossman D.C. , Cumberland D.C. , Holt C.M.
Published: September 2007

Previous studies have shown that inhibition of the proto-oncogene c-
myb
inhibits neointimal formation in various animal models. However, the temporal and spatial expression of c-Myb in the vessel wall after injury is not known, and the mechanism of action of antisense oligonucleotide (AS-ODN-c-
myb
) inhibition remains unclear. One potential effect of cell cycle dysregulation by inhibition of c-
myb
is an increase in the rates of apoptosis. In this study, c-Myb expression after percutaneous transluminal coronary angioplasty (PTCA) injury and induction of apoptosis after AS-ODN-c-
myb
treatment were determined. Immunohistochemistry and cellular phenotyping were used to localize c-Myb expression in porcine coronary arteries at various time intervals after PTCA. In vitro, the effects of AS-ODN-c-
myb
on the apoptosis of porcine vascular smooth muscle cells (PVSMCs) and endothelial cells were determined by using a cell-death ELISA and time-lapse video microscopy. In vivo, local delivery of AS-ODN-c-
myb
was performed after PTCA of pig coronary arteries, and apoptosis was quantified at 6 hours. c-Myb is induced in pig coronary arteries after angioplasty, with maximal expression in inflammatory cells at 18 hours and in vascular smooth muscle cells at 3 to 7 days. In vitro, AS-ODN-c-
myb
enhanced PVSMCs (6.8±0.8% [
P
=<0.001] versus 0.5% serum) but not endothelial cell apoptosis (1.4±0.5% [
P
=NS] versus 0.5% serum). In vivo, 6 hours after porcine coronary angioplasty and delivery of AS-ODN-c-
myb
, the proportion of apoptotic cells within the media was 4.2±0.8% (PTCA alone), 2.3±0.2% (PTCA+vehicle), and 9.0±1.1% (PTCA+AS-ODN-c-
myb
;
P
<0.05 versus PTCA alone and
P
<0.01 versus PTCA+saline). c-Myb is expressed after PTCA of pig coronary arteries, and AS-ODN-c-
myb
induces apoptosis of PVSMCs in vitro and medial cells in vivo.
Cysteinyl Leukotrienes Modulate Angiotensin II Constrictor Effects on Aortas From Streptozotocin-Induced Diabetic Rats
Authors: Hardy Gaëlle , Stanke-Labesque Franfcoise , Peoc’h Michel , Hakim Ahmed , Devillier Philippe , Caron Françoise , Morel Sandrine , Faure Patrice , Halimi Serge , Bessard Germain
Published: September 2007

Angiotensin II (Ang II) is a vasopressor peptide involved in the pathogenesis of cardiovascular diseases associated with diabetes mellitus. We have previously reported that the 5-lipoxygenase-derived products, particularly the cysteinyl leukotrienes (CysLTs), are involved in Ang II-induced contraction. In this study, we demonstrated that CysLTs contribute to the contraction elicited by Ang II in isolated aortas from streptozotocin-induced diabetic (SS) rats but not from insulin-treated diabetic rats, fructose-fed rats, or control rats. In an organ bath, pretreatment with the 5-lipoxygenase inhibitor (AA861, 10 μmol/L) reduced by 37.6±8.2% and 30.1±10.9% the Ang II-induced contractions in intact and endothelium-denuded aortic rings, respectively, from SS rats. In contrast, the CysLT
1
receptor antagonist (MK571, 1 μmol/L) or the dual CysLT
1
/CysLT
2
receptor antagonist (BAY-u9773, 0.1 μmol/L) did not affect Ang II-induced contraction. In addition, Ang II induced a 6.2±1.5-fold increase in CysLT release through the stimulation of the Ang II type 1 receptor. Furthermore, the urinary excretion of leukotriene E
4
was increased in SS rats (leukotriene E
4
, 13.7±2.9 ng/24 h [SS rats, n=10] versus 1.5±0.5 ng/24 h [control rats, n=6];
P
<0.0004). These data suggest the activation of the 5-lipoxygenase pathway in SS rats and the involvement of 5-lipoxygenase-derived products, particularly the CysLTs, in Ang II-induced contraction in aortas from SS rats through stimulation of CysLT receptors different from the well-characterized CysLT
1
or CysLT
2
receptor.
Tumor Necrosis Factor Receptor Superfamily 14 Is Involved in Atherogenesis by Inducing Proinflammatory Cytokines and Matrix Metalloproteinases
Authors: Lee Won-Ha , Kim Se-Hwa , Lee Yoon , Lee Byung Boong , Kwon Byungsuk , Song Hebok , Kwon Byoung S. , Park Jeong-Euy
Published: September 2007

Tumor necrosis factor (TNF) receptor superfamily 14 (TNFRSF14) is the cellular receptor for TNF superfamily 14 (LIGHT). Immunohistochemical staining of human carotid atherosclerotic plaques revealed a high level of expression of the TNFRSF14 in regions rich in macrophages/foam cells. To investigate the role of TNFRSF14 in the functioning of monocytes in relation to atherogenesis, we have analyzed TNFRSF14 expression levels and cellular events after stimulation of TNFRSF14 in peripheral blood monocytes or the human macrophage–like cell line, THP-1. A high level of expression of TNFRSF14 was detected in activated monocytes, in macrophages derived from monocytes, and in THP-1 cells. Concomitant activation of THP-1 cells with interferon-γ and immobilized anti-TNFRSF14 monoclonal antibody resulted in synergistic induction of proatherogenic cytokines, such as TNF-α and interleukin-8. Activation of THP-1 cells with immobilized anti-TNFRSF14 monoclonal antibody induced expression of matrix metalloproteinase (MMP)-1, MMP-9, MMP-13, and tissue inhibitors of metalloproteinase-1 and -2. Furthermore, immunohistochemical staining of atherosclerotic plaques with severe infiltration of foam cells revealed that the expression patterns of TNFRSF14 and MMP-1, -9, and -13 overlapped. Treatment of THP-1 cells with soluble LIGHT also caused induction of MMP-9 and interleukin-8. These data suggest that TNFRSF14 is involved in atherosclerosis via the induction of proatherogenic cytokines and decreasing plaque stability by inducing extracellular matrix–degrading enzymes.
NO Modulates Monocyte Chemotactic Protein-1 Expression in Endothelial Cells Under Cyclic Strain
Authors: Wung B.S. , Cheng J.J. , Shyue S.-K. , Wang D.L.
Published: September 2007

Endothelial cells (ECs) under hemodynamic forces increase intracellular reactive oxygen species (ROS) that modulate gene expression. We previously showed that NO attenuated the shear flow–induced gene level. The present study explored the role of endothelial NO in cyclic strain–treated ECs. Treatment of ECs with
S
-nitroso-
N
-acetylpenicillamine (SNAP), an NO donor, reduced cyclic strain–induced monocyte chemotactic protein (MCP)-1 expression. Conversely, exposure of ECs to an NO synthase inhibitor augmented MCP-1 mRNA levels. NO attenuated the binding of activator protein-1 to the 12-
O
-tetradecanoylphobol-13-acetate–responsive element (TRE) in the MCP-1 promoter region. ECs overexpressed with endothelial NO synthase (eNOS) inhibited cyclic strain–induced MCP-1 expression and MCP-1 promoter (−540 bp) activity. Consistently, ECs treated with SNAP or infected with adenovirus carrying eNOS reduced strain-induced superoxide levels. These strain-induced superoxide and MCP-1 expressions were greatly blunted by treating ECs with an NADPH oxidase inhibitor, diphenyleneiodonium chloride or apocynine, but not with a xanthine oxidase inhibitor. ECs infected with adenovirus carrying the dominant-negative mutant of Rac (RacN17), a component of NADPH oxidase, reduced the strain-induced superoxide and MCP-1 expression. In contrast, ECs transfected with a constitutively active Rac (RacV12) increased MCP-1 and 4× TRE promoter activities. However, ECs cotransfected with eNOS and RacV12 reduced those promoter activities. Consistently, the increases of superoxide levels and MCP-1 expression by overexpression of RacV12 were abolished after infecting ECs with eNOS. Our results show that NO from eNOS-inhibiting redox-sensitive MCP-1 expression is mediated via Rac-dependent NADPH oxidase by reducing ROS. This study provides a molecular basis to support the notion that endothelial NO acts as an antioxidant by negatively regulating redox-sensitive gene expression in ECs constantly under hemodynamic influence.
Arg123-Tyr166 Domain of Human ApoA-I Is Critical for HDL-Mediated Inhibition of Macrophage Homing and Early Atherosclerosis in Mice
Authors: Holvoet Paul , Peeters Kathleen , Lund-Katz Sissel , Mertens Ann , Verhamme Peter , Quarck Rozenn , Stengel Dominique , Lox Marleen , Deridder Els , Bernar Hilde , Nickel Margaret , Theilmeier Gregor , Ninio Ewa , Phillips Michael C.
Published: September 2007

Atherosclerosis was studied in apolipoprotein E (apoE) knockout mice expressing human apolipoprotein A-I (apoA-I) or an apoA-I/apolipoprotein A-II (apoA-II) chimera in which the Arg123-Tyr166 central domain of apoA-I was substituted with the Ser12-Ala75 segment of apoA-II. High density lipoprotein (HDL) cholesterol levels were identical in apoA-I and apoA-I/apoA-II mice, but at 4 months, plaques were 2.7-fold larger in the aortic root of the apoA-I/apoA-II mice (P<0.01). The macrophage–to–smooth muscle cell ratio of lesions was 2.1-fold higher in apo-I/apoA-II mice than in apoA-I mice (
P
<0.01). This was due to a 2.7-fold higher (
P
<0.001) in vivo macrophage homing in the aortic root of apoA-I/apoA-II mice. Plasma platelet-activating factor acetyl hydrolase activity was lower (
P
<0.01) in apoA-I/apoA-II mice, resulting in increased oxidative stress, as evidenced by the higher titer of antibodies against oxidized low density lipoprotein (
P
<0.01). Increased oxidative stress resulted in increased stimulation of ex vivo macrophage adhesion by apoA-I/apoA-II β-very low density lipoprotein and decreased inhibition of β-very low density lipoprotein–induced adhesion by HDL from apoA-I/apoA-II mice. The cellular cholesterol efflux capacity of HDL from apoA-I/apoA-II mice was very similar to that of apoA-I mice. Thus, the Arg123-Tyr166 central domain of apoA-I is critical for reducing oxidative stress, macrophage homing, and early atherosclerosis in apoE knockout mice independent of its role in HDL production and cholesterol efflux.
Long-Term Homocysteine-Lowering Treatment With Folic Acid Plus Pyridoxine Is Associated With Decreased Blood Pressure but Not With Improved Brachial Artery Endothelium-Dependent Vasodilation or Carotid Artery Stiffness
Authors: van Dijk Robert A.J.M. , Rauwerda Jan A. , Steyn Mieke , Twisk Jos W.R. , Stehouwer Coen D.A.
Published: September 2007

Homocysteine is associated with atherothrombotic disease, which may be mediated through associations of homocysteine levels with blood pressure, endothelial function, or arterial stiffness. In a placebo-controlled, randomized clinical trial, we measured blood pressure, brachial artery endothelium-dependent vasodilation, and common carotid artery stiffness in 158 clinically healthy siblings of patients with premature atherothrombotic disease at baseline and after 1 and 2 years of homocysteine-lowering treatment with folic acid (5 mg) plus pyridoxine (250 mg). Intention-to-treat analyses limited to participants (n=130) who underwent at least 1 measurement after the baseline visit showed that compared with placebo, treatment with folic acid plus pyridoxine was associated with a 3.7-mm Hg (95% CI −6.8 to −0.6 mm Hg) lower systolic and a 1.9-mm Hg (95% CI −3.7 to −0.02 mm Hg) lower diastolic blood pressure over the 2-year trial period. Together with the decreased occurrence of abnormal exercise electrocardiography tests reported previously, our results support the hypothesis that homocysteine-lowering treatment with folic acid plus pyridoxine has beneficial vascular effects. Because no effects could be demonstrated on brachial artery endothelium-dependent vasodilation or on common carotid artery stiffness, the present study does not support the hypothesis that the cardiovascular effects of homocysteine are mediated through these factors, at least in clinically healthy individuals.
Genome-Wide Linkage Analysis of Lipids in the Hypertension Genetic Epidemiology Network (HyperGEN) Blood Pressure Study
Authors: Coon Hilary , Leppert Mark F. , Eckfeldt John H. , Oberman Albert , Myers Richard H. , Peacock James M. , Province Michael A. , Hopkins Paul N. , Heiss Gerardo
Published: September 2007

Full genome scans were performed for quantitative lipid measurements in 622 African American and 649 white sibling pairs not taking lipid-lowering medications who were ascertained through the Hypertension Genetic Epidemiology Network (HyperGEN) of the National Heart, Lung, and Blood Institute (NHLBI) Family Blood Pressure Program. Genotypes for 391 markers spaced roughly equally throughout the genome were typed by the NHLBI Mammalian Genotyping Service. Each of the phenotypes was adjusted for covariates within sex and race and then subjected to variance components linkage analysis, which was performed separately within race by using race-specific marker allele frequencies from additional random samples. The highest lod score detected was 2.77 for logarithmically transformed triglyceride (TG) on chromosome 20 (at 28.6 cM) in the African American sibling pairs. The highest score detected in the white sibling pairs was 2.74 for high density lipoprotein cholesterol on chromosome 5 (at 48.2 cM). Although no scores >3.0 were obtained, positive scores were found in several regions that have been reported in other genome scans in the literature. For example, a score of 1.91 for TG was found on chromosome 15 (at 28.8 cM) in white sibling pairs. This score overlaps the positive findings for TG in 2 other genome scans.
Differential Cell Cycle Progression Patterns of Infiltrating Leukocytes and Resident Cells After Balloon Injury of the Rat Carotid Artery
Authors: Hay Carl , Micko Connie , Prescott Margaret Forney , Liau Gene , Robinson Keith , De Leon Hector
Published: September 2007

The heterogeneous nature of the cell populations involved in vascular repair remains a major hurdle for the assessment of the cellular events that take place in injured arteries. The present experiments were designed to estimate the proportions and cell cycle progression of infiltrating leukocytes versus resident vascular cells after balloon injury of the rat common carotid artery. After tissue disaggregation, cell suspension samples from each artery were analyzed by flow cytometry. Cells were stained with anti-CD45 or anti–α-smooth muscle actin antibodies to identify leukocytes and smooth muscle cells, respectively. A day after injury, a 12-fold increase in CD45+ leukocytes was found. Double labeling with CD45 and CD-3, ED-1, or granulocyte markers revealed that most infiltrating cells were monocytes and granulocytes. Approximately 14% of infiltrating leukocytes were found to enter apoptosis at day 1, and 17% entered S phase at day 3. In contrast, the highest proliferation rate of resident α-smooth muscle actin–positive cells was observed at day 7 (19%). The present results demonstrate that infiltrating leukocytes and resident vascular smooth muscle cells have dissimilar cell cycle profiles. Furthermore, our study demonstrates the feasibility of using flow cytometry to quantitatively determine the cell types and their relative activation state in injured arteries.
PPARγ and Atherosclerosis
Authors: Hsueh Willa A. , Law Ronald E.
Published: September 2007

Atherosclerosis is a major vascular complication of diabetes and the primary cause of mortality in persons with this disease. Metabolic abnormalities related to the Insulin Resistance Syndrome or Metabolic Syndrome may importantly contribute to the increased risk of atherosclerosis associated with diabetes. Thiazolidinediones (TZDs) are oral insulin sensitizers in broad clinical use that enhance insulin-stimulated glucose uptake into skeletal muscle. TZDs can also improve cardiovascular risk factors and exert direct effects on vascular cells to potentially retard the atherosclerotic process. Direct vascular effects of TZDs likely result from their activity as ligands for the nuclear receptor, PPARγ. All of the major cell types in the vasculature express PPARγ, including intimal macrophages and vascular smooth muscle cells (VSMCs) in human atheroma. TZDs block VSMC growth by inducing cell cycle arrest in G1 through an inhibition of retinoblastoma protein phosphorylation. Migration of monocytes and VSMCs is also inhibited by TZDs, possibly through decreased matrix metalloproteinase production. Activation of PPARγ by TZDs in macrophages induces ABCA1 transporter expression to promote reverse cholesterol transport. These antiatherogenic activities may also occur in vivo because TZDs have been shown to inhibit lesion formation in several animal models. Thus, TZD activation of PPARγ may protect against atherosclerosis both by normalizing proatherogenic metabolic abnormalities of the insulin resistance/diabetes milieu and through an inhibition of vascular cell growth and movement.
Activation of p38 Mitogen-Activated Protein Kinases by Endothelin and Noradrenaline in Small Arteries, Regulation by Calcium Influx and Tyrosine Kinases, and Their Role in Contraction
Authors: Ohanian Jacqueline , Cunliffe Pamela , Ceppi Enrico , Alder Angela , Heerkens Egidius , Ohanian Vasken
Published: September 2007

Abstract
—

Small-artery responses to vasoconstrictor agonists are important for vascular function. To investigate the signaling pathways involved in contraction, we studied the activation and regulation of p38 mitogen-activated protein kinases (p38MAPKs) and heat shock protein (HSP) kinase by endothelin and noradrenaline in rat mesenteric arteries. Both vasoconstrictors activated p38α and/or p38β but not p38γ or p38δ, leading to increased HSP kinase activity. p38MAPK activation by noradrenaline was maximum between 2 and 10 minutes and was wholly dependent on calcium influx but insensitive to the tyrosine kinase inhibitor herbimycin A. In contrast, endothelin induced a biphasic response, with activation at 2 and 10 minutes. The early activity was wholly dependent on calcium influx and inhibited by herbimycin A. The later activity was only 50% calcium dependent, was insensitive to herbimycin A, but was 50% inhibited by genistein, a nonselective tyrosine kinase inhibitor. With both agonists, p38MAPK activity returned to basal by 30 minutes. SB203580, a p38MAPK inhibitor, blocked agonist-induced HSP kinase activity, and herbimycin A inhibited activation by endothelin but not by noradrenaline. In addition, SB203580 inhibited noradrenaline-induced contraction but had little effect on contraction to endothelin. These data show that vasoconstrictors use different upstream activators of p38MAPK in vascular tissue and that the p38MAPK pathway is selectively implicated in the contractile response to noradrenaline in small arteries.
Identification of Differentially Regulated Genes in Mildly Hyperlipidemic ApoE3-Leiden Mice by Use of Serial Analysis of Gene Expression
Authors: Kreeft Arja J. , Moen Corina J.A. , Hofker Marten H. , Frants Rune R. , Vreugdenhil Erno , Gijbels Marion J.J. , Havekes Louis M. , Datson Nicole A.
Published: September 2007

Although genes determining lipoprotein homeostasis and atherosclerosis are the subject of intensive investigation, only a subset of these genes is known at present. Hence, we do not have sufficient knowledge to explain the genetic basis of hyperlipidemia in the majority of subjects. Our aim was to identify novel genes and pathways underlying lipoprotein homeostasis by using serial analysis of gene expression. The liver expression profile of mild hyperlipidemic apolipoprotein E3-Leiden (E3L) transgenic mice was compared with that of the wild-type C57BL/6JIco (B6) mice. Over 18 000 liver transcripts of B6 as well as E3L mice were analyzed, representing >9400 unique genes. One hundred seventy-five genes showed altered expression between the strains (
P
<0.05). Although several of these genes belonged to known metabolic pathways, such as lipoprotein metabolism, detoxification processes, glycolysis, and the acute-phase response, most were novel. Differential gene expression of 8 of 10 genes tested could be confirmed by Northern blot analysis. This inventory of differentially expressed genes will provide a unique basis for detailed studies to gain more insight into their role in lipoprotein homeostasis and atherosclerosis.
Intrarenal Transport and Vasoactive Substances in Hypertension
Authors: Ortiz Pablo A. , Garvin Jeffrey L.
Published: September 2007

Abstract
—

— Blood pressure is influenced by several vasoactive factors that also regulate nephron transport. An imbalance in regulation of salt reabsorption by the nephron contributes to hypertension. In the spontaneously hypertensive rat (SHR), the responses to dopamine and angiotensin II in the proximal nephron are diminished and enhanced, respectively. This partially explains why the proximal tubule of SHR absorbs more salt and water than that of normotensive controls. In the Dahl salt-sensitive rat, defects in NO signaling and alterations in the arachidonic acid/cytochrome P450 pathways are associated with increased salt reabsorption by the thick ascending limb. In other animal models, such as the deoxycorticosterone acetate (DOCA)-salt rat, hypertension develops as the result of an induced hormonal imbalance. By mimicking the effects of aldosterone, DOCA stimulates sodium reabsorption in the collecting ducts, causing salt and fluid retention. Thus, this model is similar to inherited forms of human hypertension caused by abnormal regulation of transport by mineralocorticoids, such as apparent mineralocorticoid excess and glucocorticoid-remediable aldosteronism. Overall, these findings demonstrate the significance of vasoactive compounds in regulating nephron transport and controlling blood pressure. However, important questions regarding humoral control of nephron transport and its implications in hypertension remain unanswered, and intensive research in these areas is required.
Hemodynamic and Metabolic Profile in Offspring of Malignant Hypertensive Parents
Authors: Lopes Heno F. , Bortolotto Luiz A. , Szlejf Cláudia , Kamitsuji Carla S. , Krieger Eduardo M.
Published: September 2007

Abstract
—

— Malignant hypertension is a serious form of arterial hypertension in which the physiopathological mechanisms include increased activity of the sympathetic nervous system, renin angiotensin system, and endothelium dysfunction. Family history of hypertension is an important predictive factor for hypertension and is associated with metabolic and hemodynamic abnormalities. Studies of these abnormalities in malignant hypertensive offspring have not yet been published. Therefore, we studied 42 offspring of malignant hypertensive parents (OMH group: age, 22±7 years; 23 male subjects; 27 white) and 35 offspring of normotensive parents (ONT group: age, 21±4 years; 23 male subjects; 25 white). All subjects had blood pressure <140/90 mm Hg. We evaluated body mass index; office blood pressure; 24-hour ambulatory and continuous beat-to-beat blood pressure monitoring (Finapres); biochemical analysis, including total cholesterol and fractions, triglycerides, glucose, and insulin; and hormonal analysis, including plasma renin activity, aldosterone, and catecholamines. The subjects were also submitted to cold pressure test and handgrip measurements. The body mass index was significantly higher in the OMH group (24±5 kg/m
2
) than in the ONT group (22±4 kg/m
2
). The OMH group showed significantly higher blood pressure and heart rate in office and Finapres measurements (
P
<0.05). In 24-hour ambulatory monitoring, the OMH group presented higher 24-hour blood pressure and heart rate, higher blood pressure during the night, and higher heart rate variability during the day compared with those of the ONT group. They also presented lower HDL cholesterol, higher levels of plasma insulin and norepinephrine, and higher insulin-to-glucose ratio (
P
<0.05) than the ONT group. There were no differences in the other biochemical parameters measured. In conclusion, OMH subjects show early hemodynamic, neurohumoral, and metabolic alterations that are typical of hypertensive metabolic syndrome.
Insulin-Mimetic Action of Vanadate
Authors: Barbagallo Mario , Dominguez Ligia J. , Resnick Lawrence M.
Published: September 2007

Abstract
—

— The insulin-mimetic effect of vanadate is well established, and vanadate has been shown to improve insulin sensitivity in diabetic rats and humans. Although the exact mechanism(s) remain undefined, we have previously demonstrated a direct relation of intracellular free magnesium (Mg
i
) levels to glucose disposal, to insulinemic responses following glucose loading, and to insulin-induced ionic effects. To investigate whether the insulin-mimetic effects of vanadate could similarly be mediated by Mg
i
, we utilized
31
P-nuclear magnetic resonance spectroscopy to measure Mg
i
in erythrocytes from normal (NL, n=10) and hypertensive (HTN, n=12) subjects, before and after incubation with insulin and with different doses of sodium vanadate. In NL, vanadate elevated Mg
i
levels, with maximum efficacy at 50 7mgr;mol/L (186±6 to 222±6 7mgr;mol/L,
P
>0.01), as did physiologically maximal doses of insulin, 200 7mgr;U/mL (185±6 to 222±8 7mgr;mol/L,
P
<0.01). In HTN, only vanadate, but not insulin, increased Mg
i
(insulin: 173±7 to 180±9 7mgr;mol/L,
P
=NS; vanadate: 170±7 to 208±10 7mgr;mol/L,
P
<0.01). Mg
i
responses to insulin (
r
=0.637,
P
<0.001), but not to vanadate (
r
=0.15,
P
=NS), were closely and directly related to basal Mg
i
levels. We conclude that (1) both vanadate and insulin stimulate erythrocyte Mg
i
levels; (2) cellular Mg
i
responses to insulin, but not to vanadate, depend on basal Mg
i
content—the lower the basal Mg
i
, the less the Mg
i
response to insulin. As such, (3) Mg
i
responses to vanadate were equivalent among HTN and NL, whereas HTN cells exhibited blunted Mg
i
responses to insulin, and (4) the ability of vanadate to improve insulin sensitivity clinically may be mediated, at least in part, by its ability to increase Mg
i
levels, which in turn, helps to determine cellular insulin action.
Omapatrilat in Subtotal Nephrectomy-Salt Hypertension
Authors: Supowit Scott C. , Zhao Huawei , Wang Donna H. , DiPette Donald J.
Published: September 2007

Abstract
—

— Calcitonin gene-related peptide (CGRP), a potent vasodilator neuropeptide, plays a counterregulatory role in subtotal nephrectomy–salt (SN-salt)–induced hypertension, reflecting a stimulation of the efferent vasodilator function of perivascular sensory nerves. To determine the effect of omapatrilat, a dual ACE and neutral endopeptidase inhibitor, on blood pressure and the potential antihypertensive role for CGRP, 24 male Sprague-Dawley rats were separated into 4 groups: (1) SN-salt, (2) SN-salt plus omapatrilat (80 mg · kg
−1
· d
−1
in the drinking water), (3) sham-operated plus salt, (4) sham-operated plus salt and omapatrilat. After 11 days the mean arterial pressure was higher in the SN-salt group (174±10 mm Hg) versus the sham-operated–salt (109±4 mm Hg) and sham-operated–salt plus omapatrilat (105±3 mm Hg) groups. Omapatrilat treatment of the SN-salt rats significantly decreased the mean arterial pressure to 123±7 mm Hg and significantly reduced the heart-to-body weight ratio. Intravenous administration of a specific CGRP receptor antagonist produced a significant 10±2 mm Hg mean arterial pressure increase in the untreated SN-salt hypertensive rats but was without effect in the other groups. This indicates that CGRP does not contribute to the antihypertensive actions of omapatrilat. In addition, CGRP mRNA and protein content in dorsal root ganglia were decreased ≈25% in the SN-salt plus omapatrilat rats. Thus, omapatrilat not only markedly reduces the blood pressure in this model of renal failure–induced hypertension but may also prevent the abnormal compensatory stimulation of the vasodilator activity of the peripheral sensory nervous system.