bluuebunny/crossref_metadata_2025 huggingface dataset:
Protection of Human Endothelial Cells From Oxidative Stress
Authors: Cuda Giovanni , Paternò Roberto , Ceravolo Roberto , Candigliota Mafalda , Perrotti Nicola , Perticone Francesco , Faniello Maria Concetta , Schepis Filippo , Ruocco Antonio , Mele Evelina , Cassano S. , Bifulco Maurizio , Santillo Mariarosaria , Avvedimento Enrico V.
Published: July 2002

Background
—

Reactive oxygen species play a critical role in inducing apoptosis. The small GTPase p21 Ras and the ERK1/2 MAPK have been proposed as key regulators of the signaling cascade triggered by oxidative stress (H
2
O
2
). Harvey-Ras (Ha-Ras) and Kirsten-Ras (Ki-Ras) isoforms are so far functionally indistinguishable, because they activate the same downstream effectors, including ERK1/2. Moreover, ERK1/2 signaling has been involved in both protection and induction of apoptosis.

Methods and Results
—

Human umbilical vein endothelial cells (HUVECs) were subjected to H
2
O
2
, and apoptosis was detected by fluorescence-activated cell sorting analysis, fluorescence microscopy, and caspase-3 activation. Transfection of Ha-
Ras
and Ki-
Ras
genes in HUVECs was performed to evaluate the response to H
2
O
2
. We have found that, whereas Ha-
Ras
decreases tolerance to oxidative stress, Ki-
Ras
has a potent antiapoptotic activity. Both effects are mediated by ERK1/2. Tolerance to H
2
O
2
is encoded by a unique stretch of lysines at the COOH terminus of the Ki-Ras, lacking in Ha-Ras, and it is relatively independent of the farnesylated anchor. Inhibition of p21 Ras signaling by farnesylation inhibitors increased the resistance to apoptosis in Ha-Ras–expressing cells.

Conclusions
—

These findings explain the opposite effects of ERK1/2 stimulation on apoptosis found in different cell types and suggest that local activation of ERK1/2 signaling may account for the opposing response to oxidative stress by Ha-Ras or Ki-Ras–expressing cells. Modulation of cell reactivity to oxidative stress by p21 Ras points to the specific and predictive effects of
Ras
inhibitors in vivo as potential therapeutic drugs in disorders produced by increase of reactive oxygen species inside the cells.
HMG-CoA Reductase Inhibitors Suppress Intracellular Calcium Mobilization and Membrane Current Induced by Lysophosphatidylcholine in Endothelial Cells
Authors: Yokoyama Keiko , Ishibashi Toshiyuki , Ohkawara Hiroshi , Kimura Junko , Matsuoka Isao , Sakamoto Takayuki , Nagata Kenji , Sugimoto Koichi , Sakurada Sotaro , Maruyama Yukio
Published: July 2002

Background
—

Lysophosphatidylcholine (LPC) is known to increase intracellular Ca
2+
concentration ([Ca
2+
]
i
) in endothelial cells. This study was conducted to investigate the effects of HMG-CoA reductase inhibitors (statins) on the increase in [Ca
2+
]
i
and membrane current induced by LPC.

Methods and Results
—

[Ca
2+
]
i
was determined in cultured human aortic endothelial cells by fura-2 assay, and membrane current was measured by whole-cell patch clamp. The [Ca
2+
]
i
increase induced by LPC was abolished by inhibitors of phospholipase C (PLC). Statins markedly decreased the [Ca
2+
]
i
increase caused by LPC. This suppressive effect was quickly reversed by geranylgeranylpyrophosphate (GGPP) and was mimicked by inhibitors of Rho and Rho kinase. LPC induced the translocation of the GTP-bound active form of RhoA into membranes within 1 minute as determined by a pull-down assay and reduced the levels of RhoA in the cytoplasm, indicating that LPC quickly increases the GTP/GDP ratio of RhoA and induces membrane translocation. Statins prevented the GTP/GDP exchange of RhoA and its membrane translocation from the cytoplasm caused by LPC, and these effects of statins were reversed by GGPP. The responses of RhoA activation to statins and GGPP concurred with their effects on Ca
2+
mobilization. LPC also induced a nonselective cation current after a lag. Statins prolonged the lag and decreased the current amplitude, and GGPP abolished the inhibitory effect on the current.

Conclusions
—

LPC induced Ca
2+
mobilization and membrane current via a Rho activation–dependent PLC pathway in endothelial cells, and statins blocked these effects by preventing the GGPP-dependent lipid modification of Rho. The present study implicates Rho in LPC stimulation of Ca
2+
movement.
Remodeling of Left Ventricular Hypertrophy in Elite Athletes After Long-Term Deconditioning
Authors: Pelliccia Antonio , Maron Barry J. , De Luca Rosanna , Di Paolo Fernando M. , Spataro Antonio , Culasso Franco
Published: July 2002

Background—

The clinical significance and long-term consequences of left ventricular (LV) hypertrophy associated with intensive athletic conditioning remain unresolved.

Methods and Results—

We prospectively evaluated 40 elite male athletes who had shown marked LV cavity enlargement of ≥60 mm, wall thickness of ≥13 mm, or both in a longitudinal fashion with serial echocardiograms, initially at peak training (age 24±4 years) and subsequently after a long-term deconditioning period (1 to 13 years; mean, 5.6±3.8). After detraining, LV cavity dimension decreased by 7% (61.2±2.9 to 57.2±3.1 mm;
P
<0.001), maximum wall thickness by 15% (12.0±1.3 to 10.1±0.8 mm;
P
<0.001), and mass normalized to height by 28% (194±25 to 140±21 g/m;
P
<0.001). However, individual subject analysis showed persistent substantial cavity dilatation (≥60 mm) in 9 athletes (22%); in contrast, wall thickness returned to normal in each athlete. Multiple regression analysis demonstrated that approximately 50% of the incomplete reduction in cavity dimension was explained by increased body weight and recreational physical activity performed during the follow-up period. No athlete had developed cardiac symptoms, impaired exercise performance, or evidence of LV dysfunction.

Conclusions—

LV remodeling was evident after long-term detraining, with significant reduction in cavity size and normalization of wall thickness. Resolution of cavity enlargement was, however, incomplete in most cases, and substantial chamber dilatation persisted in >20% of athletes. The possibility that this residual LV hypertrophy, apparently part of the athlete’s heart syndrome, may have future long-term clinical implications in some individuals cannot be excluded with certainty.
Peroxisome Proliferator–Activated Receptor α Gene Regulates Left Ventricular Growth in Response to Exercise and Hypertension
Authors: Jamshidi Yalda , Montgomery Hugh E. , Hense Hans-Werner , Myerson Saul G. , Torra Ines Pineda , Staels Bart , World Michael J. , Doering Angela , Erdmann Jeanette , Hengstenberg Christian , Humphries Steve E. , Schunkert Heribert , Flavell David M.
Published: July 2002

Background

—

Left ventricular hypertrophy (LVH) occurs as an adaptive response to a physiological (such as exercise) or pathological (valvular disease, hypertension, or obesity) increase in cardiac work. The molecular mechanisms regulating the LVH response are poorly understood. However, inherited defects in fatty acid oxidation are known to cause severe early-onset cardiac hypertrophy. Peroxisome proliferator–activated receptor α (PPARα) regulates genes responsible for myocardial fatty acid oxidation and is downregulated during cardiac hypertrophy, concomitant with the switch from fatty acid to glucose utilization.

Methods and Results

—

The role of PPARα in left ventricular growth was investigated in 144 young male British Army recruits undergoing a 10-week physical training program and in 1148 men and women participating in the echocardiographic substudy of the Third Monitoring Trends and Determinants in Cardiovascular Disease (MONICA) Augsburg study. A G/C polymorphism in intron 7 of the PPARα gene significantly influenced left ventricular (LV) growth in response to exercise (
P
=0.009). LV mass increased by 6.7±1.5 g in G allele homozygotes but was significantly greater in heterozygotes for the C allele (11.8±1.9 g) and in CC homozygotes (19.4±4.2 g). Likewise, C allele homozygotes had significantly higher LV mass, which was greater still in hypertensive subjects, and a higher prevalence of LVH in the Third MONICA Augsburg study.

Conclusions

—

We demonstrate that variation in the PPARα gene influences human left ventricular growth in response to exercise and hypertension, indicating that maladaptive cardiac substrate utilization can play a causative role in the pathogenesis of LVH.
Coronary Magnetic Resonance Angiography in Adolescents and Young Adults With Kawasaki Disease
Authors: Greil Gerald F. , Stuber Matthias , Botnar René M. , Kissinger Kraig V. , Geva Tal , Newburger Jane W. , Manning Warren J. , Powell Andrew J.
Published: July 2002

Background

—

In patients with Kawasaki disease, serial evaluation of the distribution and size of coronary artery aneurysms (CAA) is necessary for risk stratification and therapeutic management. Although transthoracic echocardiography is often sufficient for this purpose initially, visualization of the coronary arteries becomes progressively more difficult as children grow. We sought to prospectively compare coronary magnetic resonance angiography (MRA) and x-ray coronary angiography findings in patients with CAA caused by Kawasaki disease.

Methods and Results

—

Six subjects (age 10 to 25 years) with known CAA from Kawasaki disease underwent coronary MRA using a free-breathing T2-prepared 3D bright blood segmented k-space gradient echo sequence with navigator gating and tracking. All patients underwent x-ray coronary angiography within a median of 75 days (range, 1 to 359 days) of coronary MRA. There was complete agreement between MRA and x-ray angiography in the detection of CAA (n=11), coronary artery stenoses (n=2), and coronary occlusions (n=2). Excellent agreement was found between the 2 techniques for detection of CAA maximal diameter (mean difference=0.4±0.6 mm) and length (mean difference=1.4±1.6 mm). The 2 methods showed very similar results for proximal coronary artery diameter (mean difference=0.2±0.5 mm) and CAA distance from the ostia (mean difference=0.1±1.5 mm).

Conclusion

—

Free-breathing 3D coronary MRA accurately defines CAA in patients with Kawasaki disease. This technique may provide a non-invasive alternative when transthoracic echocardiography image quality is insufficient, thereby reducing the need for serial x-ray coronary angiography in this patient group.
Homocysteine Induces 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Vascular Endothelial Cells
Authors: Li Hong , Lewis Avalyn , Brodsky Sergey , Rieger Robert , Iden Charles , Goligorsky Michael S.
Published: July 2002

Background
—

It has been established that hyperhomocyst(e)inemia (HHCy) is an independent and graded risk factor for atherosclerosis, although the molecular link to the atherosclerotic process remains obscure.

Methods and Results
—

Screening human umbilical vein endothelial cells (HUVECs) with complementary DNA microarray for the gene expression modified by homocysteine (Hcy) revealed that 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) was upregulated. This effect was confirmed using quantitative reverse transcriptase-polymerase chain reaction. Actinomycin D studies revealed that Hcy stabilized HMGCR mRNA (τ
1/2
, 9.5±1.0 versus 5.0±0.2 hours). Expression of immunodetectable HMGCR in both HUVECs and renal microvascular endothelial cells was increased in Hcy-treated cells in association with the increased abundance of caveolin. Application of a cell-permeable superoxide dismutase mimetic, Mn-TBAP, reversed the Hcy-induced expression of HMGCR. Additional biochemical analysis of the abundance of total cellular cholesterol showed that 0, 20, 50, and 100 μmol/L Hcy resulted in 22.2±7.3%, 39.5±1.2%, and 50.4±6.8% increase, respectively. Gas chromatography mass spectrometry analysis of extracted cholesterol from Hcy-treated HUVECs and from the culture medium showed 17.8±5.2% and 24.0±14.5% increases, respectively. Application of simvastatin to Hcy-treated cells reduced cellular cholesterol and prevented Hcy-induced suppression of NO production by HUVECs in a dose-dependent manner.

Conclusions
—

Using a cDNA microarray, the data disclosed an unexpected link between Hcy and cholesterol dysregulation based on the finding of increased abundance of HMGCR mRNA and protein in endothelial cells, demonstrated the possible role of Hcy-induced oxidative stress in this response, and revealed the improvement of endothelial NO production in Hcy-treated HUVECs by statins. Collectively, these findings may provide a solid explanation for the observed proatherogenic effect of HHcy.
Mechanism of the Blood Pressure—Raising Effect of Cocaine in Humans
Authors: Tuncel Meryem , Wang Zhongyun , Arbique Debbie , Fadel Paul J. , Victor Ronald G. , Vongpatanasin Wanpen
Published: July 2002

Background
—

Although the sympathomimetic actions and cardiovascular complications of cocaine are ascribed to inhibition of norepinephrine (NE) reuptake, this hypothesis has not been tested in humans. We asked (a) whether cocaine can inhibit NE reuptake in the human peripheral circulation and (b) whether the NE-mediated peripheral vasoconstriction is the main mechanism mediating blood pressure-raising effect of cocaine.

Methods and Results
—

In 15 healthy cocaine-naive subjects, we measured blood pressure, forearm blood flow, and forearm venous NE concentration during administration of (a) intrabrachial cocaine (0.15 and 15 mg), which produced no systemic neurohormonal effects, and (b) intranasal cocaine (2 mg/kg). Intrabrachial cocaine (0.15 mg) increased venous forearm NE concentration by 82% and vascular resistance by 71% (
P
<0.01). Increasing the intrabrachial cocaine dose by 100-fold to match the venous cocaine level of massive cocaine overdose caused a small additional increase in venous forearm NE concentration without causing significant additional vasoconstriction. Although intranasal cocaine (2 mg/kg) matched the venous cocaine concentrations caused by 0.15 mg of intrabrachial cocaine, venous NE concentration was unchanged as sympathetic nerve activity (SNA) decreased reflexively as the result of an increase in blood pressure. When SNA was restored to baseline by blunting the cocaine-induced rise in blood pressure (baroreflex activation) with nitroprusside, venous NE concentration increased to the same level caused by intrabrachial cocaine.

Conclusions
—

In healthy cocaine-naive individuals, cocaine can inhibit NE reuptake in the human peripheral circulation. However, this mechanism does not contribute importantly to the blood pressure-raising effect of cocaine because activation of baroreceptor reflexes decreases SNA, the neural stimulus for NE release.
Determinants of Accelerated Progression of Arterial Stiffness in Normotensive Subjects and in Treated Hypertensive Subjects Over a 6-Year Period
Authors: Benetos Athanase , Adamopoulos Chris , Bureau Jeanne-Marie , Temmar Mohamed , Labat Carlos , Bean Kathryn , Thomas Frédérique , Pannier Bruno , Asmar Roland , Zureik Mahmoud , Safar Michel , Guize Louis
Published: July 2002

Background

—

Elastic artery stiffness, a result of arterial aging, is an independent indicator of cardiovascular risk. The aim of the present longitudinal study was to compare the progression of aortic stiffness over a 6-year period in treated hypertensive subjects and normotensive subjects, and to evaluate the determinants of this progression.

Methods and Results

—

Data for the present analysis were gathered from 483 subjects who had 2 health checkups at the Centre d’Investigations Préventives et Cliniques, the first one in 1992–1993 and the second one in 1998–1999. Carotid-femoral pulse wave velocity (PWV) was used to evaluate aortic stiffness in 187 hypertensive subjects who were under treatment at the time of the first visit and throughout the follow-up period, and in 296 subjects who were classified as normotensive during the first visit and who remained treatment-free throughout the follow-up period. In both populations, PWV progression was higher in older subjects. Annual rates of progression in PWV in treated hypertensives were significantly higher than in normotensives. Only treated hypertensives with well-controlled blood pressure levels at the time of both visits had a PWV progression similar to that of normotensives. In treated hypertensives, high heart rate and high creatinine during the first visit were associated with an accelerated progression in PWV.

Conclusions

—

The presence of high blood pressure, high heart rate, and high serum creatinine were the major determinants of accelerated progression of aortic stiffness in treated hypertensives. This is the first longitudinal study to evaluate the determinants of arterial aging over an extended period of time.
Heart Failure and Ventricular Dysfunction in Patients With Single or Systemic Right Ventricles
Authors: Piran Sanaz , Veldtman Gruschen , Siu Samuel , Webb Gary D. , Liu Peter P.
Published: July 2002

Background

—

Previous studies suggested a high incidence of congestive heart failure in patients with single and/or systemic right ventricles. The corresponding risk in an adult population is unknown.

Methods and Results

—

A cohort of 188 consecutive adult patients with single or systemic right ventricles was prospectively assessed with gated radionuclide angiography (n=135) or 2D echocardiography (n=188) and followed up clinically. Clinical assessment showed 82.4% of the patients were in New York Heart Association class I or II, 13.3% were in class III, and 4.3% were in class IV. Heart failure occurred in 22.2% of patients with transposition of the great arteries and a Mustard procedure, 32.3% of patients with congenitally corrected transposition of the great arteries, and 40% of Fontan-palliated patients. Symptomatic patients had significantly lower anaerobic thresholds (10.3±2.8 versus 13.2±4.8 mL · kg
−1
· min
−1
,
P
=0.006) and peak
·
V
o
2
(15.2±4.8 versus 20.3±6.8 mL · kg
−1
· min
−1
,
P
<0.00029). Systemic ventricular ejection fraction in symptomatic versus asymptomatic patients at rest was 34.8±15.7% versus 46.7±13.4% (
P
=0.00001). Mortality was 47.1% among symptomatic patients and 5% among asymptomatic patients at 15.7 years of postoperative follow-up. Seven of 12 patients with potentially correctable surgical lesions died or persisted in heart failure despite surgery. Best predictors for mortality were New York Heart Association class, systemic ejection fraction, and age at operation.

Conclusions

—

Patients with single or systemic right ventricles have significant risk for heart failure accompanied by high mortality. This study suggests the importance of identifying this group of patients who are at risk for heart failure and considering strategies to preserve ventricular function.
Na
+
Channel Mutation That Causes Both Brugada and Long-QT Syndrome Phenotypes
Authors: Clancy Colleen E. , Rudy Yoram
Published: July 2002

Background

—

Complex physiological interactions determine the functional consequences of gene abnormalities and make mechanistic interpretation of phenotypes extremely difficult. A recent example is a single mutation in the C terminus of the cardiac Na
+
channel, 1795insD. The mutation causes two distinct clinical syndromes, long QT (LQT) and Brugada, leading to life-threatening cardiac arrhythmias. Coexistence of these syndromes is seemingly paradoxical; LQT is associated with enhanced Na
+
channel function, and Brugada with reduced function.

Methods and Results

—

Using a computational approach, we demonstrate that the 1795insD mutation exerts variable effects depending on the myocardial substrate. We develop Markov models of the wild-type and 1795insD cardiac Na
+
channels. By incorporating the models into a virtual transgenic cell, we elucidate the mechanism by which 1795insD differentially disrupts cellular electrical behavior in epicardial and midmyocardial cell types. We provide a cellular mechanistic basis for the ECG abnormalities observed in patients carrying the 1795insD gene mutation.

Conclusions

—

We demonstrate that the 1795insD mutation can cause both LQT and Brugada syndromes through interaction with the heterogeneous myocardium in a rate-dependent manner. The results highlight the complexity and multiplicity of genotype-phenotype relationships, and the usefulness of computational approaches in establishing a mechanistic link between genetic defects and functional abnormalities.
Tissue Engineering of a Differentiated Cardiac Muscle Construct
Authors: Zimmermann W.-H. , Schneiderbanger K. , Schubert P. , Didié M. , Münzel F. , Heubach J.F. , Kostin S. , Neuhuber W.L. , Eschenhagen T.
Published: July 2002

Cardiac tissue engineering is an emerging field. The suitability of engineered heart tissue (EHT) for both in vitro and in vivo applications will depend on the degree of syncytoid tissue formation and cardiac myocyte differentiation in vitro, contractile function, and electrophysiological properties. Here, we demonstrate that cardiac myocytes from neonatal rats, when mixed with collagen I and matrix factors, cast in circular molds, and subjected to phasic mechanical stretch, reconstitute ring-shaped EHTs that display important hallmarks of differentiated myocardium. Comparative histological analysis of EHTs with native heart tissue from newborn, 6-day-old, and adult rats revealed that cardiac cells in EHTs reconstitute intensively interconnected, longitudinally oriented, cardiac muscle bundles with morphological features resembling adult rather than immature native tissue. Confocal and electron microscopy demonstrated characteristic features of native differentiated myocardium; some of these features are absent in myocytes from newborn rats: (1) highly organized sarcomeres in registry; (2) adherens junctions, gap junctions, and desmosomes; (3) a well-developed T-tubular system and dyad formation with the sarcoplasmic reticulum; and (4) a basement membrane surrounding cardiac myocytes. Accordingly, EHTs displayed contractile characteristics of native myocardium with a high ratio of twitch (0.4 to 0.8 mN) to resting tension (0.1 to 0.3 mN) and a strong β-adrenergic inotropic response. Action potential recordings demonstrated stable resting membrane potentials of −66 to −78 mV, fast upstroke kinetics, and a prominent plateau phase. The data indicate that EHTs represent highly differentiated cardiac tissue constructs, making EHTs a promising material for in vitro studies of cardiac function and tissue replacement therapy.
Loss of p53 Accelerates Neointimal Lesions of Vein Bypass Grafts in Mice
Authors: Mayr Ursula , Mayr Manuel , Li Chaohong , Wernig Florian , Dietrich Hermann , Hu Yanhua , Xu Qingbo
Published: July 2002

The transcription factor p53 is essentially involved in regulation of cell death and proliferation. Recently, we have established a mouse model for vein graft arteriosclerosis by grafting autologous jugular veins or vena cava to carotid arteries. Using this model, we studied the role of p53 in the development of vein graft arteriosclerosis in p53
−/−
mice. Four weeks after grafting, neointimal hyperplasia of vein grafts in p53
−/−
mice was increased 2-fold compared with that of wild-type controls. Cell component analysis revealed that neointimal lesions in p53
−/−
mice consisted mainly of α-actin positive smooth muscle cells (SMCs), whereas the majority of cells in wild-type mice were MAC-1 (CD11b/18)-positive at 4 weeks. Importantly, SMC apoptosis as determined by TUNEL assay was significantly reduced in p53
−/−
vein grafts. TUNEL positive cells in wild-type vein grafts markedly increased from 0.5% to 6.4% of total cells 4 weeks postoperatively, but remained virtually unchanged in p53
−/−
grafts (0.8%). Immunofluorescence analysis revealed that increased p53 expression in neointimal SMCs of wild-type, but not p53
−/−
, mice coincided with oxidative DNA damage in vein grafts. Interestingly, SMCs of p53
−/−
mice showed increased apoptosis in response to TNFα and decreased apoptosis in response to sodium nitroprusside. Additionally, p53-deficient SMCs showed a higher rate of proliferation and migration and expressed higher levels of matrix metalloproteinases. Thus, p53 deficiency accelerates neointima formation by facilitating SMC proliferation as well as abrogating cell apoptosis.
Spatiotemporal Transition to Conduction Block in Canine Ventricle
Authors: Fox Jeffrey J. , Riccio Mark L. , Hua Fei , Bodenschatz Eberhard , Gilmour Robert F.
Published: July 2002

Interruption of periodic wave propagation by the nucleation and subsequent disintegration of spiral waves is thought to mediate the transition from normal sinus rhythm to ventricular fibrillation. This sequence of events may be precipitated by a period doubling bifurcation, manifest as a beat-to-beat alternation, or alternans, of cardiac action potential duration and conduction velocity. How alternans causes the local conduction block required for initiation of spiral wave reentry remains unclear, however. In the present study, a mechanism for conduction block was derived from experimental studies in linear strands of cardiac tissue and from computer simulations in ionic and coupled maps models of homogeneous one-dimensional fibers. In both the experiments and the computer models, rapid periodic pacing induced marked spatiotemporal heterogeneity of cellular electrical properties, culminating in paroxysmal conduction block. These behaviors resulted from a nonuniform distribution of action potential duration alternans, secondary to alternans of conduction velocity. This link between period doubling bifurcations of cellular electrical properties and conduction block may provide a generic mechanism for the onset of tachycardia and fibrillation.
PPARγ but not PPARα Ligands Are Potent Repressors of Major Histocompatibility Complex Class II Induction in Atheroma-Associated Cells
Authors: Kwak Brenda R. , Myit Samir , Mulhaupt Flore , Veillard Niels , Rufer Nathalie , Roosnek Eddy , Mach François
Published: July 2002

Peroxisome proliferator-activated receptors (PPARs) are essential in glucose and lipid metabolism and are implicated in metabolic disorders predisposing to atherosclerosis, such as diabetes and dyslipidemia. Conversely, antidiabetic glitazones and hypolipidemic fibrate drugs, known as PPARγ and PPARα ligands, respectively, reduce the process of atherosclerotic lesion formation, which involves chronic immunoinflammatory processes. Major histocompatibility complex class II (MHC-II) molecules, expressed on the surface of specialized cells, are directly involved in the activation of T lymphocytes and in the control of the immune response. Interestingly, expression of MHC-II has recently been observed in atherosclerotic plaques, and it can be induced by the proinflammatory cytokine interferon-γ (IFN-γ) in vascular cells. To explore a possible role for PPAR ligands in the regulation of the immune response, we investigated whether PPAR activation affects MHC-II expression in atheroma-associated cells. In the present study, we demonstrate that PPARγ but not PPARα ligands act as inhibitors of IFN-γ–induced MHC-II expression and thus as repressors of MHC-II–mediated T-cell activation. All different types of PPARγ ligands tested inhibit MHC-II. This effect of PPARγ ligands is due to a specific inhibition of promoter IV of CIITA and does not concern constitutive expression of MHC-II. Thus, the beneficial effects of antidiabetic PPARγ activators on atherosclerotic plaque development may be partly explained by their repression of MHC-II expression and subsequent inhibition of T-lymphocyte activation.
Endothelial Dysfunction and Blood Pressure Variability in Selected Inbred Mouse Strains
Authors: Ryan Michael J. , Didion Sean P. , Davis Deborah R. , Faraci Frank M. , Sigmund Curt D.
Published: July 2002

The genetic regulation of blood pressure (BP) and endothelial function is likely to be polygenic. Because there is considerable variability in basal BP among inbred mouse strains, the purpose of this study was to determine whether a similar variability in vascular function exists among 7 “normotensive” strains. We tested the hypothesis that compared with mice with higher BPs, mice with lower BPs would have greater aortic endothelial responses to acetylcholine (ACh). Mean BP ranged from 117 to 145 mm Hg among the 7 strains. The responses of aortic rings to ACh, sodium nitroprusside, and papaverine were assessed after submaximal precontraction with prostaglandin F
2α
. The aortas from all strains relaxed in a concentration-dependent manner to sodium nitroprusside and papaverine, but responses to ACh were markedly impaired in the aortas, but not carotid arteries, from 129P3/J and 129X1/SvJ mice. Aortas from the other strains relaxed normally to ACh. Furthermore, the endothelium-dependent dilators ADP and A23187 caused similar relaxation in 129P3/J, 129X1/SvJ, and C57BL/6J mice. Although the data do not support the initial hypothesis, the impaired aortic response to ACh in the 129 strains is a novel finding and illustrates the potential impact that genetic background can have on vascular responsiveness.
Metalloproteinase Inhibition and the Response to Angioplasty and Stenting in Atherosclerotic Primates
Authors: Cherr Gregory S. , Motew Stephen J. , Travis Jeffrey A. , Fingerle Juergen , Fisher Larry , Brandl Mike , Williams J. Koudy , Geary Randolph L.
Published: July 2002

Determinants of restenosis after angioplasty include constrictive remodeling and intimal hyperplasia. Both processes require extensive matrix turnover, so matrix metalloproteinases (MMPs) have become potential targets of antirestenosis therapies. We studied the effects of RO113-2908, a broad-spectrum MMP inhibitor (MMPI), on the response to iliac artery angioplasty and stenting in atherosclerotic cynomolgus monkeys. Lumen diameter (LD) was measured angiographically, and artery wall geometry was assessed after perfusion-fixation at 4 weeks. Angiogenesis was measured in subcutaneous polyvinyl alcohol disks. Treatment provided significant, systemic MMP inhibitory activity (97±2.2% inhibition of 25 nmol/L MMP-12 by serum) and inhibited angiogenesis (
P
=0.007). In contrast, loss of gain in LD (
P
=0.73) and constrictive remodeling (external elastic lamina area ratio [injured/uninjured×100]: MMPI, 106.3±9.6% vs control, 119.9±7.2%;
P
=0.27) were not substantially improved 4 weeks after angioplasty. Treatment also failed to reduce intimal hyperplasia after angioplasty (intimal area [mm
2
]: 1.4±0.3 vs 1.6±0.2,
P
=0.65) or stenting (2.4±0.2 vs 2.8±0.2,
P
=0.12). In summary, inhibition of MMP activity reduced angiogenesis but failed to prevent constrictive remodeling or intimal hyperplasia after angioplasty and stenting in atherosclerotic primates. Additional research is needed to define the spectrum of matrix-degrading proteases critical in healing atherosclerotic arteries after angioplasty.
Pharmacokinetics and Pharmacodynamics of AJW200, a Humanized Monoclonal Antibody to von Willebrand Factor, in Monkeys
Authors: Kageyama Shunsuke , Yamamoto Hiroshi , Nakazawa Harumi , Matsushita Junko , Kouyama Tetsuya , Gonsho Akinori , Ikeda Yasuo , Yoshimoto Ryota
Published: July 2002

The interaction between platelet glycoprotein Ib and von Willebrand factor (vWF) plays a crucial role in platelet-mediated thrombus formation under high-shear-stress conditions. The aim of this study was to investigate the antiplatelet profile of a humanized anti-vWF monoclonal antibody, AJW200. In vitro studies were performed with a modified cone-and-plate viscometer and human platelets. AJW200 inhibited high-shear-stress-induced platelet adhesion, aggregation, and thrombin generation, but it did not have such effects under low-shear-stress conditions. Although abciximab inhibited platelet aggregation under both shear stress conditions, it did not inhibit platelet adhesion and thrombin generation. In addition, the pharmacokinetics and pharmacodynamics of AJW200 were evaluated in cynomolgus monkeys. Sustained inhibition of ristocetin-induced platelet aggregation was observed over 24 hours, 6 days, and 2 weeks after a single bolus injection of 0.3, 1, and 3 mg/kg, respectively. Moderate prolongation of the bleeding time was observed at the doses of 1 and 3 mg/kg. Abciximab markedly prolonged the bleeding time at 0.4 mg/kg, at which concentration complete inhibition of ADP-induced platelet aggregation was observed. These results suggest that glycoprotein Ib-vWF blockade with AJW200 results in a sustained antiplatelet effect without extensive prolongation of the bleeding time, probably due to a shear-stress-dependent inhibitory action.
Pulse-Wave Analysis
Authors: Wilkinson Ian B. , Hall Ian R. , MacCallum Helen , Mackenzie Isla S. , McEniery Carmel M. , van der Arend Bart J. , Shu Yae-Eun , MacKay Laura S. , Webb David J. , Cockcroft John R.
Published: July 2002

Currentmethods for assessing vasomotor endothelial function are impractical for use in large studies. We tested the hypothesis that pulse-wave analysis (PWA) combined with provocative pharmacological testing might provide an alternative method. Radial artery waveforms were recorded and augmentation index (AIx) was calculated from derived aortic waveforms. Thirteen subjects received sublingual nitroglycerin (NTG), inhaled albuterol, or placebo. Twelve subjects received NTG, albuterol, and placebo separately during an infusion of
N
G
-monomethyl-
l
-arginine (LNMMA) or norepinephrine. Twenty-seven hypercholesterolemic subjects and 27 controls received NTG followed by albuterol. Endothelial function was assessed by PWA and forearm blood flow in 27 subjects. Albuterol and NTG both significantly and repeatably reduced AIx (
P
<0.001). Only the response to albuterol was inhibited by LNMMA (−9.8±5.5% vs −4.7±2.7%;
P
=0.02). Baseline AIx was higher in the hypercholesterolemic subjects, who exhibited a reduced response to albuterol (
P
=0.02) but not to NTG when compared with matched controls. The responses to albuterol and acetylcholine were correlated (
r
=0.5,
P
=0.02). Consistent with an endothelium-dependent effect, the response to albuterol was substantially inhibited by LNMMA. Importantly, the response to albuterol was reduced in subjects with hypercholesterolemia and was correlated to that of intra-arterial acetylcholine. This methodology provides a simple, repeatable, noninvasive means of assessing endothelial function in vivo.
Expression and Localization of Tissue Factor Pathway Inhibitor-2 in Normal and Atherosclerotic Human Vessels
Authors: Crawley James T.B. , Goulding David A. , Ferreira Valérie , Severs Nicholas J. , Lupu Florea
Published: July 2002

Tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type, serine protease inhibitor with inhibitory activity toward activated factor XI, plasma kallikrein, plasmin, certain matrix metalloproteinases, and the tissue factor:activated factor VII complex. In this study, we investigated TFPI-2 expression and localization in normal and atherosclerotic human arteries by using in situ hybridization and immunohistochemical techniques. In healthy human blood vessels, TFPI-2 was detected in the vascular endothelium alone. In human atherosclerotic tissues, TFPI-2 expression was assigned to macrophages, T cells, endothelial cells, and smooth muscle cells. Western blot analysis for TFPI-2 confirmed its production by cultured human aortic smooth muscle cells, U937 cells (monocytes), and Jurkat (T cell) cell lines. Reverse transcription–polymerase chain reaction revealed similar TFPI-2 expression levels in both monocytes and macrophages in culture. Electron microscopic study with immunogold labeling revealed the association of TFPI-2 antigen with both the extracellular matrix and plasma membranes. TFPI-2 antigen was detected in some areas of atheroma that also stained positively for both tissue factor and factor VII. Moreover, detection of TFPI-2 in close spatial proximity to plasmin/plasminogen on macrophages, on endothelial cells, and in matrix-rich areas highlighted its possible functional significance in the regulation of plasmin activity and downstream proteolytic mechanisms that occur in the atherosclerotic lesion.
Involvement of Endothelial Nitric Oxide in Sphingosine-1-Phosphate–Induced Angiogenesis
Authors: Rikitake Yoshiyuki , Hirata Ken-ichi , Kawashima Seinosuke , Ozaki Masanori , Takahashi Tomosaburo , Ogawa Wataru , Inoue Nobutaka , Yokoyama Mitsuhiro
Published: July 2002

Nitric oxide (NO) has been implicated as a critical signaling molecule of angiogenesis. Recently, sphingosine-1-phosphate (S1P) has emerged as a mediator of angiogenesis, and S1P-induced NO synthesis in endothelial cells (ECs) has been reported. To analyze the signaling pathways involved in S1P-induced angiogenesis and clarify the role of NO in this process, we performed in vivo and in vitro angiogenesis assays. S1P activated the phosphatidylinositol-3-kinase (PI3K)/Akt/endothelial NO synthase (eNOS) pathway in ECs, since S1P-stimulated eNOS phosphorylation and NO production were blocked by inhibition of activities of PI3K and Akt. S1P increased capillary ingrowth into subcutaneously implanted Matrigel plugs in mice, and the effect of S1P was significantly reduced in mice that received
N
G
-nitro-
l
-arginine methyl ester (
l
-NAME), an inhibitor of NOS. S1P stimulated EC migration and tube formation on Matrigel, which processes were significantly decreased by inhibition of activities of PI3K, Akt, or eNOS, whereas treatment with LY294002, a PI3K inhibitor, but not
l
-NAME, inhibited EC viability and proliferation. Thus, our results demonstrate the crucial role of NO in S1P-induced angiogenesis in vivo and in vitro and suggest the divergent roles of NO in the S1P-induced angiogenic response.
Local Overexpression of Monocyte Chemoattractant Protein-1 at Vessel Wall Induces Infiltration of Macrophages and Formation of Atherosclerotic Lesion
Authors: Namiki Masayuki , Kawashima Seinosuke , Yamashita Tomoya , Ozaki Masanori , Hirase Tetsuaki , Ishida Tatsuro , Inoue Nobutaka , Hirata Ken-ichi , Matsukawa Akihiro , Morishita Ryuichi , Kaneda Yasufumi , Yokoyama Mitsuhiro
Published: July 2002

Monocyte/macrophage infiltration to the arterial wall is an initial step in atherosclerosis, and monocyte chemoattractant protein-1 (MCP-1) is thought to play a central role in the recruitment of these cells. In the present study, we examined the role of local expression of MCP-1 at the vessel wall in the initiation and development of atherosclerosis. We transfected the cDNA encoding rat MCP-1 into the vessel wall of the rabbit carotid artery with the use of the hemagglutinating virus of Japan (HVJ)-liposome method. The rabbits were divided into the following groups: (1) those fed normal chow and transfected with MCP-1-HVJ, (2) those fed a high cholesterol diet (1% cholesterol) and transfected with MCP-1-HVJ, and (3) those fed a high cholesterol diet and transfected with control-HVJ. Prescribed diets were started 2 weeks before transfection and were continued for another 2 weeks. In group 1, vascular lesion formation was not found, and anti-rabbit monocyte/macrophage antibody (RAM-11) staining for monocytes/macrophages was negative, although anti-rat MCP-1 antibody (R-17) staining for rat MCP-1 was positive mainly in endothelial cells. Cholesterol feeding increased plasma cholesterol levels to 1801±444 mg/dL in group 2. In group 2, all rabbits displayed neointimal formation with infiltration of RAM-11–positive cells, and a part of the lesion was also positive for Sudan III lipid staining. In group 3, hypercholesterolemia did not induce the infiltration of monocytes/macrophages and subsequent lesion formation in the vessel wall despite definite upregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 on the endothelium. To initiate atherosclerotic changes, local MCP-1 overexpression at the vessel is not sufficient, and activation of other factors induced by hypercholesterolemia is required.
Female Hormones and Thrombosis
Authors: Rosendaal F.R. , Helmerhorst F.M. , Vandenbroucke J.P.
Published: July 2002

Exogenous hormones are used by more than a hundred million women worldwide as oral contraceptives or for postmenopausal hormone replacement. Oral contraceptives increase the risk of venous thrombosis, of myocardial infarction, and of stroke. The risk is highest during the first year of use. The venous thrombotic risk of oral contraceptives is high among women with coagulation abnormalities and with so-called third-generation contraceptives (containing desogestrel or gestodene). The risk of myocardial infarction does not appear to depend on coagulation abnormalities or the type of oral contraceptive. Hormone replacement therapy increases the risk of venous thrombosis. This risk is also highest in the first year of use and among women with coagulation abnormalities. The risk becomes very high in women with a previous venous thrombosis. Randomized trials have not confirmed a beneficial effect of postmenopausal hormones on the occurrence of myocardial infarction.
Factor XIIIA Val34Leu Polymorphism Does Not Predict Risk of Coronary Heart Disease
Authors: Aleksic Nena , Ahn Chul , Wang Yao-Wei , Juneja Harinder , Folsom Aaron R. , Boerwinkle Eric , Wu Kenneth K.
Published: July 2002

Factor XIII catalyzes the cross-linking of fibrin. Cross-sectional studies have suggested that a common polymorphism site at residue 34 of the A subunit of factor XIII (FXIIIA) with a substitution of Leu for Val (FXIIIA Val34Leu) was associated with reduced coronary heart disease (CHD). This association has not been examined in prospective studies. Healthy subjects (n=15 792) were recruited from 4 US communities into the Atherosclerosis Risk in Communities (ARIC) study from 1987 to 1989. They were followed, and incident CHD events were identified and verified. For the present study, we included 423 patients with CHD as cases and 479 noncases. FXIIIA Val34Leu polymorphism was determined by the single-strand conformational polymorphism method. There were no significant differences in the genotype frequencies between cases and noncases. The genotypes showed little association with known CHD risk factors. A weighted proportional hazards regression analysis adjusting for other risk factors confirmed no association of the genotypes with risk of CHD. This prospective study did not provide evidence of a reduced CHD risk for the FXIIIA 34Leu allele.
Expression of Type III Hyperlipoproteinemia in Apolipoprotein E2 (Arg158→Cys) Homozygotes Is Associated With Hyperinsulinemia
Authors: de Beer Femke , Stalenhoef Anton F.H. , Hoogerbrugge Nicoline , Kastelein John J.P. , Gevers Leuven Jan A. , van Duijn Cornelia M. , Havekes Louis M. , Smelt Augustinus H.M.
Published: July 2002

Type III hyperlipoproteinemia (HLP) is mainly found in homozygous carriers of apolipoprotein E2 (apoE2, Arg158→Cys). Only a small percentage (<5%) of these apoE2 homozygotes develops hyperlipidemia, indicating that additional environmental and genetic factors contribute to the expression of type III HLP. In the present study, first, the prevalence of type III HLP among apoE2 homozygotes was estimated in a Dutch population sample of 8888 participants. Second, 68 normocholesterolemic and 162 hypercholesterolemic apoE2 homozygotes (type III HLP patients) were collected to investigate additional factors influencing type III HLP expression. In the Dutch population sample, apoE2 homozygosity occurred with a frequency of 0.6% (57 of 8888 individuals). Among the 57 E2/2 subjects, 10 type III HLP patients were identified (prevalence 18%). Comparison of normocholesterolemic E2/2 subjects and type III HLP patients showed that the latter had a significantly increased body mass index (25.6±4.0 versus 26.9±3.8 kg/m
2
, respectively;
P
=0.03) and prevalence of hyperinsulinemia (26% versus 63%, respectively;
P
<0.001). Multiple linear regression analysis demonstrated that most of the variability in type III HLP expression can be explained by fasting insulin levels (partial correlation coefficient ≈0.50,
P
<0.001). In contrast to men, apoE2 homozygous women aged ≥50 years had significantly higher plasma lipid levels than their counterparts aged <50 years. These data demonstrate that the expression of type III HLP in E2/2 subjects is elicited to a large extent by hyperinsulinemia. In addition, in female apoE2 homozygotes, the expression increases with age; this increase is most likely due to the loss of estrogen production.
Amount of
H
Antigen Expressed on Circulating von Willebrand Factor Is Modified by ABO Blood Group Genotype and Is a Major Determinant of Plasma von Willebrand Factor Antigen Levels
Authors: O’Donnell James , Boulton Frank E. , Manning Richard A. , Laffan Michael A.
Published: July 2002

To investigate whether the effect of ABO blood group on plasma von Willebrand factor (vWF) levels is mediated by the
ABH
antigenic determinants carried on
N
-linked glycans of vWF, we studied 158 group A and group O healthy volunteers. vWF antigen (vWF:Ag) and factor VIII antigen (FVIII:Ag) levels were highest in

A
1
A
1

individuals and higher in

A
1
O
1

than in

A
2
O
1

or

O
1
O
1

individuals. Plasma
A
transferase
activity and the amount of
A
antigen expressed per unit vWF (
AvWF
) were significantly higher in

A
1
A
1

than in

A
1
O
1

individuals and higher in

A
1
O
1

than in

A
2
O
1

individuals.
AvWF
was correlated strongly with plasma levels of
A transferase
activity. Thus, we have clearly demonstrated a direct relationship between
ABO
genotype,
A transferase
expression, and the amount of
A
antigen expressed on circulating vWF.
H
antigen expression per unit vWF (
HvWF
) was highest in group O individuals. Among group A individuals, the pattern of
HvWF
expression was

A
2
O
1

>

A
1
O
1

>

A
1
A
1

. In group O and group

A
2
O
1

individuals,
HvWF
was inversely correlated with plasma vWF levels. In contrast, among group

A
1
A
1

and

A
1
O
1

individuals, there was no relationship between
AvWF
and plasma vWF levels. These findings suggest that it is
H
antigen expression that mediates the ABO effect on plasma vWF concentration.
Identification of a Zinc Finger Homoeodomain Enhancer Protein After AT
2
Receptor Stimulation by Differential mRNA Display
Authors: Stoll Monika , Hahn Alfred W.A. , Jonas Uwe , Zhao Yi , Schieffer Bernhard , Fischer Jens W. , Unger Thomas
Published: July 2002

Using differential mRNA display, we isolated differentially expressed genes after stimulation of angiotensin II (Ang II) type 2 (AT
2
) receptors in PC12w cells. Among the polymerase chain reaction products isolated, we identified
Zfhep
, a zinc finger homoeodomain enhancer–binding protein and the angiotensin AT
2
receptor itself, both implicated in developmental processes. In the presence of epidermal growth factor (EGF) a concordant expression pattern of
Zfhep
and AT
2
mRNA was observed with marked downregulation 6 hours after stimulation with EGF+Ang II. In quiescent PC12w cells,
Zfhep
mRNA was time-dependently induced by Ang II (10
−7
mol/L) up to 3 hours, an effect that was blocked by the selective AT
2
antagonist PD123177 (10
−6
mol/L). We extended our studies on
Zfhep
mRNA expression to cells of vascular origin (coronary endothelial cells [CECs]), that express AT
1
and AT
2
receptors, and that respond differently to Ang II dependent on which receptor subtype is stimulated. In CECs,
Zfhep
mRNA expression was induced up to 3 hours after AT
2
stimulation. Interestingly, this
Zfhep
induction was observed only when the AT
1
receptor was blocked by using the selective AT
1
receptor antagonist, losartan (10
−5
mol/L), suggesting a negative-regulatory influence of AT
1
receptors on AT
2
-induced
Zfhep
mRNA induction. In conclusion,
Zfhep
not only represents a suitable marker for AT
2
receptor activation, but it may also link AT
2
signaling and downstream events involved in the proposed function of the AT
2
receptor in development and regeneration.