bluuebunny/crossref_metadata_2025 huggingface dataset:
Overexpression of a Constitutively Active Protein Kinase G Mutant Reduces Neointima Formation and In-Stent Restenosis
Authors: Sinnaeve Peter , Chiche Jean-Daniel , Gillijns Hilde , Van Pelt Natascha , Wirthlin Douglas , Van de Werf Frans , Collen Desire , Bloch Kenneth D. , Janssens Stefan
Published: July 2002

Background
—

Neointima formation after arterial injury is associated with reduced vascular cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase (PKG), a major cGMP effector in vascular smooth muscle. We tested the effect of PKG overexpression on the neointimal response to vascular injury.

Methods and Results
—

Infection of cultured rat aortic smooth muscle cells (RASMCs) with an adenoviral vector specifying a cGMP-independent, constitutively active PKG mutant (AdPKGcat) reduced serum-induced migration by 33% and increased serum-deprivation–induced apoptosis 2-fold (
P
<0.05 for both). Infection with wild-type PKG (AdPKG), in the absence of cGMP, did not affect migration or apoptosis. Two weeks after balloon-injured rat carotid arteries were infected with 1× 10
10
pfu AdPKGcat (n=12), AdPKG (n=8), or a control adenovirus (n=8), intima-to-media ratio was less in AdPKGcat-infected arteries than in AdPKG- or control adenovirus–infected vessels (0.26±0.06 versus 0.61±0.12 and 0.70±0.12, respectively,
P
<0.05 for both). Two weeks after intramural administration of 1.75×10
10
pfu AdPKGcat (n=8) or a control adenovirus (n=8) into porcine coronary arteries with in-stent restenosis, luminal diameter was greater in AdPKGcat-infected arteries than in control adenovirus-infected vessels (2.32±0.16 versus 1.81±0.13 mm,
P
=0.028), associated with reduced neointimal area (3.30±0.24 versus 4.15±0.13 mm
2
,
P
=0.008), neointima-to-vessel area ratio (0.42±0.05 versus 0.58±0.04,
P
<0.05), and percent stenosis (45±6% versus 70±4%,
P
<0.05).

Conclusions
—

Expression of a constitutively active PKG reduces neointima formation after balloon injury in rats and reduces coronary in-stent restenosis in pigs. PKGcat gene transfer may be a promising strategy for vasculoproliferative disorders.
Home-Based Intervention in Congestive Heart Failure
Authors: Stewart Simon , Horowitz John D.
Published: July 2002

Background
—

It is not known to what extent initially observed benefits of postdischarge programs of care for patients with chronic congestive heart failure (CHF) in respect to event-free survival, readmissions, and healthcare costs persist in the long term.

Methods and Results
—

We prospectively studied the long-term effects of a multidisciplinary home-based intervention (HBI) in a cohort of CHF patients randomly allocated to either to HBI (n=149) or usual care (n=148). During a median of 4.2 years of follow-up, there were significantly fewer primary end points (unplanned readmission or death) in the HBI versus usual care group: a mean of 0.21 versus 0.37 primary events per patient per month (
P
<0.01). Median event-free survival was more prolonged in the HBI than usual care group (7 versus 3 months;
P
<0.01). Fewer HBI patients died (56% versus 65%;
P
=0.06) and had more prolonged survival (a median of 40 versus 22 months;
P
<0.05) compared with usual care. Assignment to HBI was both an independent predictor of event-free survival (RR 0.70;
P
<0.01) and survival alone (RR 0.72;
P
<0.05). Overall, HBI patients had 78 fewer unplanned readmissions compared with usual care (0.17 versus 0.29 readmissions per patient per month;
P
<0.05). The median cost of these readmissions was $A325 versus $A660/month per HBI and usual care patient (
P
<0.01).

Conclusions
—

The beneficial effects of HBI in reducing frequency of unplanned readmissions in CHF patients persist in the long term and are associated with prolongation of survival.
Nitric Oxide Modulates Myocardial Oxygen Consumption in the Failing Heart
Authors: Chen YingJie , Traverse Jay H. , Du Ruisheng , Hou MingXiao , Bache Robert J.
Published: July 2002

Background

—

Endogenous nitric oxide (NO) has been reported to inhibit oxygen consumption in the normal heart, so that nonselective inhibition of NO synthase (NOS) caused an increase of myocardial oxygen consumption (MV̇O
2
). Although endothelial NOS responses are depressed in congestive heart failure (CHF), inducible NOS (iNOS) may be expressed in failing myocardium.

Methods and Results

—

This study tested the hypothesis that NOS inhibition would increase MV̇O
2
in the failing heart. CHF was produced in dogs by use of the rapid ventricular pacing model. In comparison with normal values, animals with CHF had reduced coronary blood flow and MV̇O
2
at rest, with a blunted response to treadmill exercise. Selective iNOS inhibition with
S
-methylisothiourea (1.5 mg/kg IC) increased left ventricular systolic pressure and left ventricular dP/dt and caused an increase in MV̇O
2
at rest and during exercise (
P
<0.05), with a parallel upward shift in the relationship between MV̇O
2
and rate-pressure product. In contrast,
S
-methylisothiourea had no effect on MV̇O
2
or coronary flow in normal animals, although nonselective NOS inhibition with
N
G
-nitro-
l
-arginine did cause an increase of MV̇O
2
in normal and in CHF animals.

Conclusions

—

The results indicate that endogenous NO can modulate MV̇O
2
in failing hearts, but unlike the normal heart, this NO appears to be produced, at least in part, by iNOS.
Expression of CYR61, an Angiogenic Immediate Early Gene, in Arteriosclerosis and Its Regulation by Angiotensin II
Authors: Hilfiker Andres , Hilfiker-Kleiner Denise , Fuchs Martin , Kaminski Karol , Lichtenberg Artur , Rothkötter Hermann-Josef , Schieffer Bernhard , Drexler Helmut
Published: July 2002

Background

—

The renin-angiotensin system is thought to be involved in development and progression of arteriosclerosis, thereby contributing to adverse cardiovascular events. To elucidate the role of angiotensin II (Ang II) at a cellular level, we analyzed the Ang II–induced gene expression profile.

Methods and Results

—

Genes induced on Ang II stimulation (10
−7
mol/L, 45 minutes) in rat smooth muscle cells were analyzed by polymerase chain reaction selected subtraction. In addition to known genes, such as
interleukin 6, leukemia inhibitory factor
, and c-
fos
, we identified
CYR61
, an angiogenic immediate early gene. Northern blot analysis revealed a rapid 2.5-fold increase of
CYR61
transcript levels by Ang II, peaking at 30 minutes, which was blunted by Ang II type 1 receptor blockade. Exposure of rat aortic rings to Ang II (30 minutes) revealed a 2-fold, and intraperitoneal injection of Ang II (30 minutes) in mice a 3-fold, increase of aortic
CYR61
transcripts. In arteriosclerotic aortas of apolipoprotein E–deficient mice,
CYR61
transcripts confirmed by in situ hybridization and proteins shown by immunohistochemistry were elevated, whereas they were hardly detectable in wild types. In human carotid atherectomies and arteriosclerotic coronary arteries, immunohistochemical analysis revealed expression of CYR61 within connective tissue in neointima, adventitia, and surrounding small capillaries and blood vessels, colocalized with ACE and Ang II. Normal human arteries showed no significant staining for CYR61.

Conclusions

—

CYR61, an angiogenic factor, is induced by Ang II in vascular cells and tissue. The expression of CYR61, colocalized with Ang II and ACE, in small vessels of human arteriosclerotic lesions is consistent with the notion that the activated renin-angiotensin system may contribute to plaque neovascularization by enhancing regulators of microvessel formation and cell proliferation.
Involvement of Glycoprotein VI in Platelet Thrombus Formation on Both Collagen and von Willebrand Factor Surfaces Under Flow Conditions
Authors: Goto Shinya , Tamura Noriko , Handa Shunnosuke , Arai Morio , Kodama Kumi , Takayama Hiroshi
Published: July 2002

Background

—

We studied the role of glycoprotein (GP) VI in platelet adhesion and thrombus formation on the immobilized collagen and von Willebrand factor (vWF) surface under flow conditions.

Methods and Results

—

Whole blood obtained from 2 patients with GP VI–deficient platelets and the effects of the Fab of anti–GP VI antibody (Fab/anti–GP VI) were tested. Blood containing platelets rendered fluorescent by mepacrine was perfused on immobilized type I collagen or vWF under controlled wall shear rate. Platelet adhesion and thrombus formation were detected by epifluorescent videomicroscopy. The percentage of surface coverage by the platelets was calculated. Fc receptor γ-chain and spleen tyrosine kinase (Syk) were immunoprecipitated from the lysate of platelets stimulated by vWF plus ristocetin and then analyzed by antiphosphotyrosine immunoblotting. No platelet attachment was seen on the surface of collagen even after 9 minutes of perfusion of blood at relatively low (100 s
−1
) or high (1500 s
−1
) wall shear rate, either in the case of blood containing GP VI–deficient platelets or in the presence of Fab/anti–GP VI, whereas significant platelet thrombus formation was noted after control blood perfusion. Such interference with the actions of GP VI also reduced firm platelet adhesion on immobilized vWF. vWF-induced tyrosine phosphorylation of GP VI–associated Fc receptor γ-chain followed by Syk activation occurred in normal platelets, but little activation of Syk occurred in GP VI–deficient platelets.

Conclusions

—

GP VI plays crucial roles in platelet thrombus formation on the surface of collagen under flow conditions in humans and is also involved in the process of firm platelet adhesion on the surface of vWF.
Decompression-Triggered Positive-Pressure Ventilation During Cardiopulmonary Resuscitation Improves Pulmonary Gas Exchange and Oxygen Uptake
Authors: Kleinsasser Axel , Lindner Karl H. , Schaefer Andreas , Loeckinger Alexander
Published: July 2002

Background

—

Intermittent positive-pressure ventilation (IPPV) is the “gold standard” of ventilation during cardiopulmonary resuscitation (CPR), but continuous positive airway pressure (CPAP) is increasingly discussed as an alternative. This study investigated hemodynamics and pulmonary gas exchange applying CPAP enhanced with pressure support ventilation (CPAP
PSV
) during CPR.

Methods and Results

—

Twenty-four pigs were subjected to ventricular fibrillation and CPR with CPAP
PSV
, CPAP, or IPPV. Measurements were taken before (hemodynamics, blood gases, inert gas measurements) and 10 (hemodynamics, blood gases) and 20 (hemodynamics, blood gases, inert gas measurements) minutes after induction of ventricular fibrillation. Although no significant intergroup differences in hemodynamics were found, arterial partial pressure of oxygen (Pa
o
2
) was significantly higher during CPAP
PSV
compared with CPAP or IPPV (98±10, 61±27, and 71±30 mm Hg, respectively,
P
<0.05). CPAP
PSV
resulted in an alveolar-arterial partial pressure of oxygen difference of 56±17 mm Hg, whereas during CPAP, 83±21 mm Hg was detected, and during IPPV, 98±29 mm Hg was detected (
P
<0.05). Pulmonary blood flow to lung units with a normal V̇
a
/

ratio in percent of cardiac output was 76±17% during CPAP
PSV
, 61±21% during CPAP (
P
<0.01), and 54±13% during IPPV (
P
<0.01). Oxygen uptake (V̇
o
2
) was significantly higher during CPAP
PSV
than with the other ventilation modes (
P
<0.05) and comparable to the baseline value in intragroup comparison. Return of spontaneous circulation was recorded in 8 of 8 animals in the CPAP
PSV
group, in 6 of 8 in the CPAP group, and in 3 of 8 in the IPPV group.

Conclusions

—

CPAP
PSV
provides a straightforward and effective alternative to IPPV or CPAP during CPR that provides significantly higher Pa
o
2
and V̇
o
2
.
Nifedipine Indirectly Upregulates Superoxide Dismutase Expression in Endothelial Cells via Vascular Smooth Muscle Cell–Dependent Pathways
Authors: Fukuo Keisuke , Yang Jin , Yasuda Osamu , Mogi Masaki , Suhara Toshimitsu , Sato Naoyuki , Suzuki Takashi , Morimoto Shigeto , Ogihara Toshio
Published: July 2002

Background

—

Calcium antagonists normalize endothelial dysfunction in many cardiovascular diseases. There is no known receptor, however, for calcium antagonists in endothelial cells (ECs). We hypothesized that vascular smooth muscle cells (VSMCs) are involved in the mechanism underlying the normalization of endothelial dysfunction by calcium antagonists.

Methods and Results

—

Coculture studies with ECs and VSMCs were performed to determine whether VSMCs mediate modulation of endothelial superoxide dismutase (SOD) activity and expression induced by the calcium antagonist nifedipine. Nifedipine induced upregulation of SOD activity in rat aortic segments but had no effect on SOD expression or activity in ECs or VSMCs cultured individually. When ECs were cocultured with VSMCs, however, nifedipine upregulated SOD expression and activity in ECs. Nifedipine stimulated vascular endothelial growth factor (VEGF) production from VSMCs, and this stimulation of VEGF production was abolished by HOE-140, an antagonist of the bradykinin B
2
receptor. A neutralizing antibody against VEGF inhibited the upregulation of endothelial SOD by nifedipine. In addition, recombinant VEGF induced an increase in the levels of SOD expression in ECs, and supernatant derived from nifedipine-treated VSMCs enhanced NO production from ECs. This increase in NO production by the supernatant was inhibited by preincubation of ECs with SOD antisense oligodeoxyribonucleotides.

Conclusions

—

The calcium antagonist nifedipine indirectly upregulates endothelial SOD expression by stimulating VEGF production from adjacent VSMCs. This finding may provide further insight into the mechanism underlying the beneficial effects of calcium antagonists in cardiovascular diseases.
Sustained Ventricular Arrhythmias Among Patients With Acute Coronary Syndromes With No ST-Segment Elevation
Authors: Al-Khatib Sana M. , Granger Christopher B. , Huang Yao , Lee Kerry L. , Califf Robert M. , Simoons Maarten L. , Armstrong Paul W. , Van de Werf Frans , White Harvey D. , Simes R. John , Moliterno David J. , Topol Eric J. , Harrington Robert A.
Published: July 2002

Background

—

The prognosis of ventricular arrhythmias among patients with non–ST-elevation acute coronary syndromes is unknown. We studied the incidence, predictors, and outcomes of sustained ventricular arrhythmias in 4 large randomized trials of such patients.

Methods and Results

—

We pooled the datasets of the Global Use of Streptokinase and tPA for Occluded Arteries (GUSTO)-IIb, Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT), Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network (PARAGON)-A, and PARAGON-B trials (n=26 416). We identified independent predictors of ventricular fibrillation (VF) and ventricular tachycardia (VT) and compared the 30-day and 6-month mortality rates of patients who did (n=552) and did not (n=25 864) develop these arrhythmias during the index hospitalization. Independent predictors of in-hospital VF included prior hypertension, chronic obstructive pulmonary disease, prior myocardial infarction, and ST-segment changes at presentation. Except for hypertension, these variables also independently predicted in-hospital VT. In Cox proportional-hazards modeling, in-hospital VF and VT were independently associated with 30-day mortality (hazard ratio [HR], 23.2 [95% CI, 18.1 to 29.8] for VF and HR, 7.6 [95% CI, 5.5 to 10.4] for VT) and 6-month mortality (HR, 14.8 [95% CI, 12.1 to 18.3] for VF and HR, 5.0 [95% CI, 3.8 to 6.5] for VT). These differences remained significant after excluding patients with heart failure or cardiogenic shock and those who died <24 hours after enrollment.

Conclusions

—

Despite the use of effective therapies for non–ST-elevation acute coronary syndromes, ventricular arrhythmias in this setting are associated with increased 30-day and 6-month mortality. More effective therapies are needed to improve the survival of patients with these arrhythmias.
Hyperemic Stenosis Resistance Index for Evaluation of Functional Coronary Lesion Severity
Authors: Meuwissen Martijn , Siebes Maria , Chamuleau Steven A.J. , van Eck-Smit Berthe L.F. , Koch Karel T. , de Winter Robbert J. , Tijssen Jan G.P. , Spaan Jos A.E. , Piek Jan J.
Published: July 2002

Background

—

Both coronary blood flow velocity reserve (CFVR) and myocardial fractional flow reserve (FFR) are used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between CFVR and FFR have been observed in 25% to 30% of intermediate coronary lesions. An index of stenosis resistance based on a combination of intracoronary pressure and flow velocity may improve the assessment of functional coronary lesion severity.

Methods and Results

—

Single photon emission computed tomography (SPECT) was performed in 151 patients with angina to determine reversible perfusion defects within one-week before cardiac catheterization. Coronary pressure and flow velocity was measured distal to 181 single coronary lesions with a mean diameter stenosis of 56% (range: 32% to 85%). Maximum hyperemia was induced by 15 to 20 μg IC adenosine to determine CFVR, FFR, and the hyperemic stenosis resistance index (h-SRv), defined as the ratio of hyperemic stenosis pressure gradient (mean aorta pressure-mean distal pressure) and hyperemic average peak-flow velocity. Receiver-operating-characteristic curves of CFVR, FFR, and h-SRv were calculated to evaluate the predictive value for presence of reversible perfusion defects on SPECT with the use of the area under curve (AUC). The AUC was significantly higher for h-SRv (0.90±0.03) compared with those for CFVR (0.80±0.04;
P
=0.024) and FFR (0.82±0.03;
P
=0.018), respectively. Agreement with SPECT was particularly higher (73%) than for CFVR (49%,
P
=0.022) or FFR (51%,
P
=0.037) in the group of lesions showing discordant results between CFVR and FFR

Conclusion

—

These results indicate that hyperemic stenosis resistance index is a more powerful predictor of reversible perfusion defects than CFVR or FFR.
Gadolinium-Enhanced 3-Dimensional Magnetic Resonance Angiography of Pulmonary Blood Supply in Patients With Complex Pulmonary Stenosis or Atresia
Authors: Geva Tal , Greil Gerald F. , Marshall Audrey C. , Landzberg Michael , Powell Andrew J.
Published: July 2002

Background

—

In patients with complex pulmonary stenosis or atresia, a detailed delineation of all sources of pulmonary blood supply is necessary for planning surgical and transcatheter procedures and usually requires diagnostic cardiac catheterization. The goals of this study were to determine whether gadolinium-enhanced 3D magnetic resonance angiography (MRA) can provide a noninvasive alternative to diagnostic catheterization and to compare MRA and x-ray angiography measurements of pulmonary arteries and aortopulmonary collaterals (APCs).

Methods and Results

—

Thirty-two patients with pulmonary stenosis or atresia (median age: 4.7 years, range: 1 day to 46.9 years) underwent both MRA and cardiac catheterization (median time: 1 month). Diagnoses included tetralogy of Fallot (TOF) with pulmonary atresia (n=13), TOF with pulmonary stenosis (n=4), post-Fontan palliation (n=5), and other complex congenital heart disease (n=10). Compared with catheterization and surgical observations, MRA had a 100% sensitivity and specificity for the diagnosis of main (n=10) and branch pulmonary artery (PA) stenosis or hypoplasia (n=38), as well as absent (n=5) or discontinuous (n=4) branch PAs. All 48 major APCs diagnosed by catheterization were correctly diagnosed by MRA. Three additional APCs were diagnosed by MRA but not by catheterization. The mean difference between MRA and catheterization measurements of 33 pulmonary vessel diameters was 0.5±1.5 mm, with a mean interobserver difference of 0.4±1.5 mm.

Conclusions

—

Gadolinium-enhanced 3D MRA is a fast and accurate technique for delineation of all sources of pulmonary blood supply in patients with complex pulmonary stenosis and atresia and can be considered a noninvasive alternative to diagnostic catheterization with x-ray angiography.
Three-Dimensional Black-Blood Cardiac Magnetic Resonance Coronary Vessel Wall Imaging Detects Positive Arterial Remodeling in Patients With Nonsignificant Coronary Artery Disease
Authors: Kim W. Yong , Stuber Matthias , Börnert Peter , Kissinger Kraig V. , Manning Warren J. , Botnar René M.
Published: July 2002

Background

—

Direct noninvasive visualization of the coronary vessel wall may enhance risk stratification by quantifying subclinical coronary atherosclerotic plaque burden. We sought to evaluate high-resolution black-blood 3D cardiovascular magnetic resonance (CMR) imaging for in vivo visualization of the proximal coronary artery vessel wall.

Methods and Results

—

Twelve adult subjects, including 6 clinically healthy subjects and 6 patients with nonsignificant coronary artery disease (10% to 50% x-ray angiographic diameter reduction) were studied with the use of a commercial 1.5 Tesla CMR scanner. Free-breathing 3D coronary vessel wall imaging was performed along the major axis of the right coronary artery with isotropic spatial resolution (1.0×1.0×1.0 mm
3
) with the use of a black-blood spiral image acquisition. The proximal vessel wall thickness and luminal diameter were objectively determined with an automated edge detection tool. The 3D CMR vessel wall scans allowed for visualization of the contiguous proximal right coronary artery in all subjects. Both mean vessel wall thickness (1.7±0.3 versus 1.0±0.2 mm) and wall area (25.4±6.9 versus 11.5±5.2 mm
2
) were significantly increased in the patients compared with the healthy subjects (both
P
<0.01). The lumen diameter (3.6±0.7 versus 3.4±0.5 mm,
P
=0.47) and lumen area (8.9±3.4 versus 7.9±3.5 mm
2
,
P
=0.47) were similar in both groups.

Conclusions

—

Free-breathing 3D black-blood coronary CMR with isotropic resolution identified an increased coronary vessel wall thickness with preservation of lumen size in patients with nonsignificant coronary artery disease, consistent with a “Glagov-type” outward arterial remodeling. This novel approach has the potential to quantify subclinical disease.
Is the Pregnancy Hormone Relaxin Also a Vasodilator Peptide Secreted by the Heart?
Authors: Fisher Carol , MacLean Margaret , Morecroft Ian , Seed Alison , Johnston Fiona , Hillier Christopher , McMurray John
Published: July 2002

Background

—

It has been shown recently that the pregnancy and parturition hormone, relaxin, is secreted by the heart. This study examined the effects of relaxin in small human resistance arteries from the systemic and pulmonary circulations.

Methods and Results

—

Arteries were obtained from gluteal biopsies and resected lung tissue and studied with the use of wire myography. Cumulative concentration relaxation curves were constructed in systemic arteries with substance P, epoprostenol, atrial natriuretic peptide, and relaxin (concentration range 10
−13
-10
−7
M). The maximal responses were 88(±5)%, 67(±10)%, 52(±16)% and 66(±16)%, respectively. Endothelium removal virtually abolished the action of relaxin. Relaxin had no vasodilator effect in pulmonary arteries.

Conclusions

—

Relaxin is a powerful dilator of systemic resistance arteries secreted by the heart that may contribute to cardiovascular regulation.
Catecholamines Block 2-Hydroxyestradiol-Induced Antimitogenesis in Mesangial Cells
Authors: Zacharia Lefteris C. , Jackson Edwin K. , Gillespie Delbert G. , Dubey Raghvendra K.
Published: July 2002

Methylation of 2-hydroxyestradiol to 2-methoxyestradiol by catechol-O-methyl transferase (COMT) mediates the antimitogenic effects of 2-hydroxyestradiol on vascular smooth muscle cells. Moreover, 2-hydroxyestradiol inhibits growth of glomerular mesangial cells (GMCs). Because catecholamines are substrates for COMT, which is expressed in GMCs, we hypothesize that catecholamines may abrogate the antimitogenic effects of 2-hydroxyestradiol on GMCs by competing for COMT and inhibiting 2-methoxyestradiol formation. To test this hypothesis, we investigated the antimitogenic effects of 2-hydroxyestradiol on rat GMCs in the presence and absence of catecholamines. The capability of GMCs to methylate 2-hydroxyestradiol in the presence and absence of catecholamines was also evaluated. GMCs metabolized 2-hydoxyestradiol in a concentration-dependent manner with a V
max
of 12.03±0.32 pmol/10
6
cells/min and an apparent K
m
of 0.23±0.04 μmol/L. Norepinephrine (10 μmol/L) and epinephrine (10 μmol/L) significantly inhibited methylation of 0.25 μmol/L 2-hydroxyestradiol. Norepinephrine concentration-dependently abrogated the ability of 2-hydroxyestradiol to inhibit
3
H-thymidine incorporation (index of DNA synthesis). In the presence of 5, 10, and 40 μmol/L norepinephrine, the inhibitory effect of 0.1 μmol/L 2-hydroxyestradiol on
3
H-thymidine incorporation was reduced from 51±0.7% to 46±0.4%, 39±0.3%, and 25±0.7%, respectively. Similar to DNA synthesis, the inhibitory effects of 2-hydroxyestradiol on cell number and
3
H-proline incorporation (index of collagen synthesis) on GMCs were abrogated by catecholamines. Our findings provide evidence that methylation of 2-hydroxyestradiol inhibits GMC proliferation and extracellular matrix synthesis and may in part protect against renal proliferative diseases. Moreover, catecholamines may abrogate the renoprotective effects of 2-hydroxyestradiol in the glomeruli by inhibiting COMT and 2-methoxyestradiol formation.
Altered Regulation of Matrix Metalloproteinase-2 in Aortic Remodeling During Aging
Authors: Wang Mingyi , Lakatta Edward G.
Published: July 2002

To elucidate potential mechanisms of enhanced type 2 matrix metalloprotease levels and activity within the thickened aged rat aorta, the present study measured its mRNA and protein levels and those of its membrane bound activator, MT1-MMP, its endogenous tissue inhibitor, TIMP-2, tissue type, and urokinase plasminogen activators and their receptors, and an inhibitor of plasminogen activation in aortae from Fisher 344X Brown Norway rats, 2 to 30 months of age. Semiquantitative immunohistochemistry, in situ hybridization, and in situ zymography of aortae detected a marked age-associated increase in gelatinolytic activity of type 2 metalloprotease within the thickened intima, internal elastic lamina, and elastic fibers in the inner part of the thickened tunica media, whereas the intimal tissue inhibitor of metalloprotease-2 mRNA and protein levels were not age related. Both activators of plasminogen and their receptors increased approximately 2-fold within the intima between 2 to 30 months. Similar, but not identical, age-associated changes in factors that regulate protease activity within the aortic media were also observed. We conclude that discordant regulation of factors that determine the activation status of type 2 matrix metalloprotease, coupled with an increase in the expression of its zymogen, occur with aging, which lead to an increase in the amount of activated protease. These factors are candidate mechanisms for age-associated vascular remodeling, a potent risk factor for vascular diseases with advancing age.
Growth of Left Ventricular Mass in African American and European American Youth
Authors: Dekkers Caroline , Treiber Frank A. , Kapuku Gaston , van den Oord Edwin J.C.G. , Snieder Harold
Published: July 2002

Increased left ventricular mass has been established as a strong risk factor for cardiovascular morbidity and mortality. To evaluate growth of left ventricular mass from childhood into early adulthood and its possible sociodemographic, anthropometric, and hemodynamic moderators, individual growth curves across age of left ventricular mass were created for 687 African American and European American males and females with a maximum of 10 annual assessments (age, 8.2 to 27.5 years). African Americans and males had significantly greater left ventricular mass (
P
<0.001) than did European Americans and females, respectively. Males also showed a larger rate of change in left ventricle mass than did girls (
P
<0.001). The ethnicity and gender effects on left ventricular mass only became apparent in early adolescence, and they persisted when controlling for socioeconomic status and anthropometric and hemodynamic variables. Body mass index and height were the strongest anthropometric predictors, and pulse pressure was the strongest hemodynamic predictor of left ventricular mass. Although significant, the contribution of pulse pressure to the prediction of left ventricular mass was small, once body mass index and height were entered into the model. The results of the present study suggest that increased left ventricular mass in boys and African Americans has its origin in late childhood. Apart from these ethnicity and gender effects, individual differences in cardiac growth can mainly be explained by body growth and increases in general adiposity.
Angiogenesis and Antifibrotic Action by Hepatocyte Growth Factor in Cardiomyopathy
Authors: Taniyama Yoshiaki , Morishita Ryuichi , Aoki Motokuni , Hiraoka Kazuya , Yamasaki Keita , Hashiya Naotaka , Matsumoto Kunio , Nakamura Toshikazu , Kaneda Yasufumi , Ogihara Toshio
Published: July 2002

Impairment of cardiac function in cardiomyopathy has been postulated to be related to decreased blood blow and increased collagen synthesis. Therefore, a therapeutic approach to alter the blood flow or fibrosis directly by means of growth factors may open a new therapeutic concept in dilated cardiomyopathy. From this viewpoint, hepatocyte growth factor (HGF) is a unique growth factor with antifibrosis and angiogenesis effects. Using the hereditary cardiomyopathic Syrian hamster as a model of genetically determined cardiomyopathy and heart failure, the effects of overexpression of HGF on fibrosis and microvascular dysfunction were examined. HGF gene or control vector was injected by the Hemagglutinating Virus of Japan–liposome method into the anterior heart of cardiomyopathic hamsters (Bio 14.6) under echocardiography once a week, from 12 to 20 weeks of age (total, 8 times). Blood flow, as assessed by a laser Doppler imager score, and the capillary density in hearts, as assessed by alkaline phosphatase staining, were significantly increased in hamsters transfected with HGF gene compared with control-vector-transfected hamsters (
P
<0.01). In contrast, the fibrotic area was significantly decreased in hamsters transfected with HGF gene compared with control (
P
<0.01). Overall, in vivo experiments demonstrated that transfection of HGF gene into the myocardium of cardiomyopathic hamsters stimulated blood flow through the induction of angiogenesis and reduction of fibrosis. These results suggest that HGF gene transfer may be useful to protect against myocardial injury in cardiomyopathy through its cardioprotective effects such as antifibrosis and angiogenesis actions.
Decreased Nitric Oxide Synthesis in Human Endothelial Cells Cultured on Type I Collagen
Authors: González-Santiago L. , López-Ongil S. , Rodríguez-Puyol M. , Rodríguez-Puyol D.
Published: July 2002

Endothelial dysfunction, considered as a defective vascular dilatation after certain stimuli, is characteristic of different pathological conditions, such as hypertension, atherosclerosis, or diabetes. A decreased synthesis or an increased degradation of nitric oxide (NO) has been postulated as the mechanism responsible for this alteration. The present experiments were designed to test the hypothesis that the presence of an abnormal extracellular matrix in vessel walls could be responsible for the decreased NO synthesis observed in these pathological conditions. Experiments were performed in cultured human umbilical vein endothelial cells (HUVECs) grown on type IV (Col. IV) or type I (Col. I) collagen. Cells seeded on Col. I showed decreased nitrite synthesis, nitric oxide synthase activity, eNOS protein content, and eNOS mRNA expression when compared with cells grown on Col. IV. Moreover, cells grown on Col. I failed to respond to glucose oxidase activation of the eNOS system. In both cases, the changes in the eNOS mRNA expression seemed to depend on the modulation of eNOS promoter activity. The downregulation of eNOS induced by Col. I was blocked by D6Y, a peptide that interferes with the Col. I-dependent signals through integrins, as well as by specific anti-integrin antibodies. Moreover, a decreased activation of integrin-linked kinase (ILK) may explain the effects observed in Col. I-cultured cells because the activity of this kinase was decreased in these cells and ILK modulation prevented the Col. I-induced changes in HUVECs. Taken together, these findings may contribute to explaining the basis of endothelial dysfunction in some vascular diseases.
Inhibition of Nitrobenzylthioinosine-Sensitive Adenosine Transport by Elevated
d
-Glucose Involves Activation of P
2Y2
Purinoceptors in Human Umbilical Vein Endothelial Cells
Authors: Parodi Jorge , Flores Carlos , Aguayo Claudio , Rudolph M. Isolde , Casanello Paola , Sobrevia Luis
Published: July 2002

Chronic incubation with elevated
d
-glucose reduces adenosine transport in endothelial cells. In this study, exposure of human umbilical vein endothelial cells to 25 mmol/L
d
-glucose or 100 μmol/L ATP, ATP-γ-S, or UTP, but not ADP or α,β-methylene ATP, reduced adenosine transport with no change in transport affinity. Inhibition of transport by
d
-glucose, ATP, and ATP-γ-S was associated with reduced maximal binding, with no changes in the apparent dissociation constant for nitrobenzylthioinosine (NBMPR). A significant reduction (≈60±10%,
P
<0.05; n=6) in the number of human equilibrative NBMPR-sensitive nucleoside transporters (hENT1s) per cell (1.8±0.1×10
6
in 5 mmol/L
d
-glucose) and in hENT1 mRNA levels was observed in cells exposed to
d
-glucose or ATP-γ-S. Incubation with elevated
d
-glucose, but not with
d
-mannitol, increased the ATP release by 3±0.2-fold . The effects of
d
-glucose and nucleotides on the number and activity of hENT1 and hENT1 mRNA were blocked by reactive blue 2 (nonspecific P
2Y
purinoceptor antagonist), suramin (Gα
s
protein inhibitor), or hexokinase but not by pyridoxal phosphate-6-azophenyl-2′,4′-disulfonic acid (nonselective P
2
purinoceptor antagonist). Our findings demonstrate that inhibition of adenosine transport via hENT1 in endothelial cells cultured in 25 mmol/L
d
-glucose could be due to stimulation of P
2Y2
purinoceptors by ATP, which is released from these cells in response to
d
-glucose. This could be a mechanism to explain in part the vasodilatation observed in the early stages of diabetes mellitus or in response to
d
-glucose infusion.
Angiotensin II Receptor–Independent Antiinflammatory and Antiaggregatory Properties of Losartan
Authors: Krämer Christine , Sunkomat Julia , Witte Jana , Luchtefeld Maren , Walden Michael , Schmidt Boris , Böger Rainer H. , Forssmann Wolf-Georg , Drexler Helmut , Schieffer Bernhard
Published: July 2002

Angiotensin II (Ang II) type 1 receptor (AT
1
) antagonists such as losartan (LOS) are widely used for the treatment of hypertension and elicit antiinflammatory and antiaggregatory in vitro and in patients, although the underlying mechanism are unclear. Following computer-based molecule similarity, we proposed that on cytochrome-P450 degradation, the LOS metabolite EXP3179 is generated, which shows molecule homology to indomethacin, a cyclooxygenase inhibitor with antiinflammatory and antiaggregatory properties. Subsequently, serum-levels of EXP3179 were determined for 8 hours in patients receiving a single oral dose of 100 mg LOS. High-performance liquid chromatography followed by liquid chromatography–mass spectrometry (LC-MS) from serum samples revealed a maximum of 10
−7
mol/L for EXP3179 peaking between 3 to 4 hours. The increase in serum-EXP3179 levels was associated with a significant reduction in platelet aggregation in vivo (−35±4%,
P
<0.001 versus control). EXP3179 generation was investigated in a chemical reaction mimicking the liver cytochrome-P450–dependent LOS-degradation and human endothelial cells were exposed to Ang II or lipopolysaccharides (LPS) in the presence of EXP3179 (10
−7
mol/L). LPS- and Ang II–induced COX-2 transcription was abolished by EXP3179. Moreover, EXP3179 significantly reduced Ang II– and LPS-induced formation of prostaglandin F2α as determined by LC-MS. Thus, antiinflammatory properties of LOS are mediated via its EXP3179 metabolite by abolishing COX-2 mRNA upregulation and COX-dependent TXA2 and PGF2α generation. Serum levels of EXP3179 are detectable in patients in concentrations that exhibit antiinflammatory and antiaggregatory properties in vitro.
all-
trans
-Retinoic Acid Increases Nitric Oxide Synthesis by Endothelial Cells
Authors: Achan Vinod , Tran Cam T.L. , Arrigoni Francesca , Whitley Guy St.J. , Leiper James M. , Vallance Patrick
Published: July 2002

all-
trans
-Retinoic acid (atRA) has important effects on the developing and mature cardiovascular system. Nitric oxide (NO) production has been associated with the atRA-induced differentiation of neuronal cells, and we hypothesized that NO may also mediate certain actions of atRA in the cardiovascular system. We studied the effects of atRA on NO production by endothelial cells and determined whether regulation of enzymes responsible for metabolism of asymmetric dimethylarginine (ADMA) contributed to the effects seen. Murine endothelioma (sEnd.1) cells were incubated with or without atRA. Nitrite production was determined using the Griess reaction. The expression of NO synthase (NOS) and dimethylarginine dimethylaminohydrolase (DDAH) genes was determined by Northern blotting. A reporter gene assay was also used to study the effect of atRA on the DDAH II promoter. atRA significantly increased nitrite production by sEnd.1 cells despite no increase in eNOS expression. atRA also increased DDAH II gene expression and promoter activity and reduced the ratio of ADMA to symmetric dimethylarginine (SDMA) in culture medium. The DDAH inhibitor 4124W significantly reduced the induction of NO synthesis by atRA. The present study demonstrates that atRA increases NO synthesis in endothelial cells without increasing eNOS expression. atRA also increases the expression of DDAH II, the predominant DDAH isoform in endothelial cells. Our data suggests that the induction of NO synthesis by atRA may be facilitated by DDAH II. This pathway may help to explain some of the effects of atRA on the cardiovascular system.
Myocardial Dysfunction With Coronary Microembolization
Authors: Thielmann Matthias , Dörge Hilmar , Martin Claus , Belosjorow Sergej , Schwanke Uwe , van de Sand Anita , Konietzka Ina , Büchert Astrid , Krüger Arne , Schulz Rainer , Heusch Gerd
Published: July 2002

Coronary microembolization results in progressive myocardial dysfunction, with causal involvement of tumor necrosis factor-α (TNF-α). TNF-α uses a signal transduction involving nitric oxide (NO) and/or sphingosine. Therefore, we induced coronary microembolization in anesthetized dogs and studied the role and sequence of NO, TNF-α, and sphingosine for the evolving contractile dysfunction. Four sham-operated dogs served as controls (group 1). Eleven dogs received placebo (group 2), 6 dogs received the NO synthase inhibitor
N
G
-nitro-
l
-arginine methyl ester (L-NAME, group 3), and 6 dogs received the ceramidase inhibitor
N
-oleoylethanolamine (NOE, group 4) before microembolization was induced by infusion of 3000 microspheres (42-μm diameter) per milliliter inflow into the left circumflex coronary artery. Posterior systolic wall thickening (PWT) remained unchanged in group 1 but decreased progressively in group 2 from 20.6±4.9% (mean±SD) at baseline to 4.1±3.7% at 8 hours after microembolization. Leukocyte count, TNF-α, and sphingosine contents were increased in the microembolized posterior myocardium. In group 3, PWT remained unchanged (20.3±2.6% at baseline) with intracoronary administration of L-NAME (20.8±3.4%) and 17.7±2.3% at 8 hours after microembolization; TNF-α and sphingosine contents were not increased. In group 4, PWT also remained unchanged (20.7±4.6% at baseline) with intravenous administration of NOE (19.5±5.7%) and 16.4±6.3% at 8 hours after microembolization; TNF-α, but not sphingosine content, was increased. In all groups, systemic hemodynamics, anterior systolic wall thickening, and regional myocardial blood flow remained unchanged throughout the protocols. A signal transduction cascade of NO, TNF-α, and sphingosine is causally involved in the coronary microembolization-induced progressive contractile dysfunction.
Evidence for Cardiomyocyte Repopulation by Extracardiac Progenitors in Transplanted Human Hearts
Authors: Laflamme Michael A. , Myerson David , Saffitz Jeffrey E. , Murry Charles E.
Published: July 2002

Human myocardium has long been considered to have essentially no intrinsic regenerative capacity. Recent studies in rodent models, however, have suggested the presence of an extracardiac stem cell population, perhaps in bone marrow, that is capable of some reconstitution of cardiomyocytes after injury. To determine whether similar mechanisms exist in the human heart, we evaluated human female allograft hearts transplanted into male patients. The presence of Y chromosomes in cardiomyocytes would indicate these cells arose from the recipient, rather than the donor heart. We identified 5 male patients who had retained a female heart at least 9 months before death and necropsy. Remarkably, in each case, the transplanted heart contained a minute but readily detectable fraction of Y chromosome-positive cardiomyocytes. The mean percentage of cardiomyocytes arising from the host was estimated to be 0.04% with a median of 0.016%. Most Y-positive cardiomyocytes were associated with regions of acute rejection, suggesting such chimerism involves an injury event. Furthermore, the sole patient whose immediate cause of death was allograft rejection showed a much higher percentage of host-derived cardiomyocytes, up to 29% in local, 1-mm
2
“hot spots.” Thus, adult humans have extracardiac progenitor cells capable of migrating to and repopulating damaged myocardium, but this process occurs at very low levels.
Locus for Elevated Apolipoprotein B Levels on Chromosome 1p31 in Families With Familial Combined Hyperlipidemia
Authors: Allayee Hooman , Krass Kelly L. , Pajukanta Päivi , Cantor Rita M. , van der Kallen Carla J.H. , Mar Rebecca , Rotter Jerome I. , de Bruin Tjerk W.A. , Peltonen Leena , Lusis Aldons J.
Published: July 2002

Familial combined hyperlipidemia (FCH), a common cause of premature coronary artery disease, is genetically complex and poorly understood. Recently, a major locus on chromosome 1q21-23 exhibiting highly significant linkage was identified in Finnish FCH families by use of a parametric analysis. We now report highly significant evidence of linkage (maximum LOD score 3.8, recombination fraction 0) of an important FCH phenotype, elevated apolipoprotein B (apoB) levels, to a distinctly separate locus on chromosome 1p31 in Dutch pedigrees. ApoB is the major protein on very low density and low density lipoproteins, and elevated apoB levels have been used as a surrogate trait for FCH. Additional microsatellite markers in the 1p31 region were genotyped, and evidence of linkage improved (maximum LOD score 4.7) in a multipoint analysis of two markers in the peak region. The leptin receptor gene resides within this locus and is involved in obesity and insulin/glucose homeostasis. However, there was no evidence of an association between leptin receptor and apoB levels, raising the possibility that another gene on this chromosomal region contributes to elevated apoB levels in this Dutch population. This is one of the first loci identified for apoB levels in humans and is the second major locus implicated in the genetic etiology of FCH.
Expression of Slow Skeletal Troponin I in Hearts of Phospholamban Knockout Mice Alters the Relaxant Effect of β-Adrenergic Stimulation
Authors: Wolska Beata M. , Arteaga Grace M. , Peña James R. , Nowak Grzegorz , Phillips Ronald M. , Sahai Shalini , de Tombe Pieter P. , Martin Anne F. , Kranias Evangelia G. , Solaro R. John
Published: July 2002

β-Adrenergic stimulation of the heart results in an enhanced relaxation rate in association with phosphorylation of both cardiac troponin I (cTnI) and phospholamban (PLB). We studied new lines of mice generated by crossbreeding mice that express slow skeletal troponin I (ssTnI) with PLB knockout (PLBKO) mice. This crossbreeding resulted in the generation of PLB/cTnI, PLB/ssTnI, PLBKO/cTnI, and PLBKO/ssTnI mice. Perfusion with isoproterenol (ISO) significantly increased the peak amplitude of fura-2 ratio in PLB/cTnI, PLBKO/cTnI, and PLBKO/ssTnI groups of mice. However, in the presence of ISO, there were no differences in the peak amplitude of fura-2 ratio among cells isolated from hearts of PLB/cTnI, PLBKO/cTnI, and PLBKO/ssTnI mice. In cells from PLB/cTnI mice, the extent of shortening was increased and the time of relaxation was significantly decreased during β-adrenergic stimulation. In PLBKO/cTnI cells, stimulation with ISO resulted in an increased extent of shortening and no change in time of relaxation. However, stimulation with ISO in cells isolated from PLBKO/ssTnI mice not only significantly increased the extent of cell shortening but also increased the time of relaxation. We also determined the kinetics of relaxation of papillary muscles isolated from all four groups of animals in the presence and absence of ISO. Perfusion with ISO increased the rate of relaxation only in PLB/cTnI, PLB/ssTnI, and PLBKO/cTnI muscles. During ISO stimulation, the time of relaxation was unchanged in PLBKO/ssTnI muscles. Our data directly demonstrate that phosphorylation of both PLB and cTnI contributes to increased rate of relaxation during β-adrenergic stimulation.
Hydroxyl Radical-Induced Acute Diastolic Dysfunction Is Due to Calcium Overload via Reverse-Mode Na
+
-Ca
2+
Exchange
Authors: Zeitz Oliver , Maass A. Eveline , Van Nguyen Phuc , Hensmann Geerd , Kögler Harald , Möller Karsten , Hasenfuss Gerd , Janssen Paul M.L.
Published: July 2002

Hydroxyl radicals (OH) are involved in the development of reperfusion injury and myocardial failure. In the acute phase of the OH-mediated diastolic dysfunction, increased intracellular Ca
2+
levels and alterations of myofilaments may play a role, but the relative contribution of these systems to myocardial dysfunction is unknown. Intact contracting cardiac trabeculae from rabbits were exposed to OH, resulting in an increase in diastolic force (F
dia
) by 540%. Skinned fiber experiments revealed that OH-exposed preparations were sensitized for Ca
2+
(EC
50
: 3.27±0.24×10
−6
versus 2.69±0.15×10
−6
mol/L;
P
<0.05), whereas maximal force development was unaltered. Western blots showed a proteolytic degradation of troponin T (TnT) with intact troponin I (TnI). Blocking of calpain I by MDL-28.170 inhibited both TnT-proteolysis and Ca
2+
sensitization, but failed to prevent the acute diastolic dysfunction in the intact preparation. The OH-induced diastolic dysfunction was similar in preparations with intact (540±93%) and pharmacologically blocked sarcoplasmic reticulum (539±77%), and was also similar in presence of the L-type Ca
2+
-channel antagonist verapamil. In sharp contrast, inhibition of the reverse-mode sodium-calcium exchange by KB-R7943 preserved diastolic function completely. Additional experiments were performed in rat myocardium; the rise in diastolic force was comparable to rabbit myocardium, but Ca
2+
sensitivity was unchanged and maximal force development was reduced. This was associated with a degradation of TnI, but not TnT. Electron microscopic analysis revealed that OH did not cause irreversible membrane damage. We conclude that OH-induced acute diastolic dysfunction is caused by Ca
2+
influx via reverse mode of the sodium-calcium exchanger. Degradation of troponins appears to be species-dependent but does not contribute to the acute diastolic dysfunction.