bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic 17β-Estradiol Replacement Increases Nitric Oxide–Mediated Vasodilation of Guinea Pig Coronary Microcirculation
Authors: Thompson Loren P. , Pinkas Gerard , Weiner Carl P.
Published: June 2012

Background
—Estrogen is cardioprotective of the coronary circulation by mechanisms incompletely understood. This study determined the effect of chronic 17β-estradiol replacement on dilator responses to acetylcholine and sodium nitroprusside of the isolated coronary microcirculation.

Methods and Results
—Adult female guinea pigs were ovariectomized, and a 21-day-release pellet containing 0.0, 0.1, 0.25, 0.5, or 1.0 mg 17β-estradiol was implanted subcutaneously. Serum estradiol concentrations ranged from 3.9 to 74.9 pg/mL, increasing with the dose of estradiol. After 19 to 20 days, the animals were euthanized, and their hearts were removed and perfused with buffer at constant flow on an isolated heart apparatus. Both perfusion pressure and contractile force were measured in prostaglandin F
2α
–constricted hearts. Vasodilation to the cumulative addition of the endothelium-dependent agonist acetylcholine (10
−
9
to 10
−
5
mol/L) and the nitric oxide (NO) donor sodium nitroprusside (10
−
9
to 10
−
5
mol/L) was measured before and after NO synthesis inhibition by nitro-
l
-arginine (LNA, 10
−
4
mol/L). Baseline coronary resistance was unaltered by estradiol, although LNA increased resistance in estradiol-treated hearts more than in ovariectomized controls. Chronic 17β-estradiol increased sensitivity (measured by −log EC
50
values) but not maximal response to acetylcholine compared with ovariectomized controls. Differences were abolished by LNA at all doses of estradiol. Sodium nitroprusside–induced dilation was unaffected by estradiol replacement.

Conclusions
—Chronic 17β-estradiol replacement, at doses producing hormone levels within the physiological range, enhances dilator sensitivity of the coronary microcirculation through enhanced NO production by the endothelium, independent of changes in NO sensitivity of the vascular smooth muscle. Thus, estradiol enhances NO production as a protective mechanism of the coronary microcirculation.
Effects of Vitamin E Supplementation on F
2
-Isoprostane and Thromboxane Biosynthesis in Healthy Cigarette Smokers
Authors: Patrignani Paola , Panara Maria R. , Tacconelli Stefania , Seta Francesca , Bucciarelli Tonino , Ciabattoni Giovanni , Alessandrini Paola , Mezzetti Andrea , Santini Giovanna , Sciulli Maria G. , Cipollone Francesco , Davı̀ Giovanni , Gallina Pietro , Bon Gabriele Bittolo , Patrono Carlo
Published: June 2012

Background
—Increased formation of 8-iso-prostaglandin (PG) F
2α
and thromboxane (TX) A
2
, potent agonists of platelet and vascular thromboxane (TH)/PGH
2
receptors, has been detected in cigarette smokers. We performed a randomized, double-blind, placebo-controlled study of the effects of vitamin E (300, 600, and 1200 mg/d, each dose for 3 consecutive weeks) on 8-iso-PGF
2α
and TXA
2
biosynthesis in 46 moderate cigarette smokers.

Methods and Results
—Urinary immunoreactive 8-iso-PGF
2α
and 11-dehydro-TXB
2
, plasma vitamin E, and serum TXB
2
were measured by previously validated techniques. Baseline urinary 8-iso-PGF
2α
and 11-dehydro-TXB
2
excretion averaged 241±78 and 430±293 pg/mg creatinine, respectively. Urinary 8-iso-PGF
2α
was significantly correlated with 11-dehydro-TXB
2
(
r
=0.360, n=138,
P
<0.0001). Baseline plasma vitamin E levels averaged 20.6±4.9 μmol/L and were inversely correlated with urinary 11-dehydro-TXB
2
(
r
=−0.304,
P
=0.039) but not with 8-iso-PGF
2α
(
r
=−0.227,
P
=0.129). Vitamin E supplementation caused a dose-dependent increase in its plasma levels that reached a plateau at 600 mg (42.3±11.2 μmol/L,
P
<0.001). This was not associated with any statistically significant change in urinary 8-iso-PGF
2α
or 11-dehydro-TXB
2
excretion.

Conclusions
—Supplementation with pharmacological doses of vitamin E has no detectable effects on lipid peroxidation and thromboxane biosynthesis in vivo in healthy subjects with a mild degree of oxidant stress. These findings are consistent with the hypothesis that the basal rate of lipid peroxidation is a major determinant of the response to vitamin E supplementation and have implications for the use of vitamin E in healthy subjects as well as for the design and interpretation of clinical trials of antioxidant intervention.
Endothelial Dysfunction in Men With Small LDL Particles
Authors: Vakkilainen Juha , Mäkimattila Sari , Seppälä-Lindroos Anneli , Vehkavaara Satu , Lahdenperä Sanni , Groop Per-Henrik , Taskinen Marja-Riitta , Yki-Järvinen Hannele
Published: June 2012

Background
—It is unknown whether LDL particle size is, independent of other lipids and lipoproteins, associated with endothelial dysfunction in vivo.

Methods and Results
—We determined in vivo endothelial function in 34 healthy men by measuring forearm blood flow responses to intrabrachial artery infusions of acetylcholine (ACh, an endothelium-dependent vasodilator) and sodium nitroprusside (an endothelium-independent vasodilator). LDL peak particle size was measured with gradient gel electrophoresis. Men with small LDL particles (LDL diameter ≤25.5 nm, n=10) had a 39% lower blood flow response to ACh than men with large LDL particles (LDL diameter >25.5 nm, n=24, blood flow 6.9±3.6 versus 11.4±5.1 mL/dL · min,
P
=0.006). The groups had comparable LDL cholesterol concentrations (3.9±0.6 versus 3.7±1.0 mmol/L, men with small versus large LDL particles), blood pressure, glucose concentrations, and body mass indexes. LDL size (
r
=0.45,
P
=0.01) but not HDL cholesterol (
r
=0.31,
P
=0.09) or triglycerides (
r
=−0.19,
P
=0.30) was significantly correlated with endothelium-dependent vasodilation. Serum triglyceride concentrations and LDL size were inversely correlated (
r
=−0.44,
P
=0.01). In multivariate regression analysis, LDL size was the only significant determinant of the ACh-induced increase in blood flow. Sodium nitroprusside–stimulated endothelium-independent vasodilation was similar in both groups.

Conclusions
—Small LDL particles are associated with impaired in vivo endothelial function independent of HDL and LDL cholesterol and triglyceride concentrations. LDL size may therefore mediate adverse effects of hypertriglyceridemia on vascular function.
Cost-Effectiveness of Treating Hyperlipidemia in the Presence of Diabetes
Authors: Grover Steven A. , Coupal Louis , Zowall Hanna , Dorais Marc
Published: June 2012

Background
—The objective of this study was to estimate the long-term costs and benefits of treating hyperlipidemia among diabetic patients with and without known cardiovascular disease after validating the Cardiovascular Life Expectancy Model.

Methods and Results
—The model estimates were compared with the Scandinavian Simvastatin Survival Study (4S) and used to estimate the long-term costs and benefits of treatment with simvastatin. Simulations were performed for men and women, 40 to 70 years of age, having pretreatment LDL cholesterol values of 5.46, 4.34, and 3.85 mmol/L (211, 168, and 149 mg/dL). We forecasted the long-term risk of cardiovascular events, the need for medical and surgical interventions, and the associated costs in 1996 US dollars. The model validated well against the observed results of the of the 4S diabetic patients. In this validation, the model estimates fell within the 95% confidence interval of the observed results for 7 of the 8 available end points (coronary deaths, total deaths, and so forth). Treatment with simvastatin for patients with cardiovascular disease is cost-effective for men and women, with or without diabetes. Among diabetic individuals without cardiovascular disease, the benefits of primary prevention were also substantial and the cost-effectiveness ratios attractive across a wide range of assumptions (≈$4000 to $40 000 per year of life saved). These conclusions were robust even among diabetics with lower baseline LDL values and smaller LDL reductions as observed in the Cholesterol and Recruitment Events (CARE) trial.

Conclusions
—Among adults with hyperlipidemia, the presence of diabetes identifies men and women among whom lipid therapy is likely to be effective and cost-effective even in the absence of other risk factors or known cardiovascular disease.
Herpesvirus Infection Accelerates Atherosclerosis in the Apolipoprotein E–Deficient Mouse
Authors: Alber Dagmar G. , Powell Kenneth L. , Vallance Patrick , Goodwin David A. , Grahame-Clarke Cairistine
Published: June 2012

Background
—Human herpesviruses have been implicated but not proven to be involved in the etiology of atherosclerosis. To determine whether there is a causal relationship, the effect of herpesvirus infection on the development of atherosclerosis was assessed in the apolipoprotein E–deficient (apoE−/−) mouse.

Methods and Results
—In the present study, 3- to 4-week-old apoE−/− mice were infected with murine γ-herpesvirus-68 (MHV-68). Atheroma formation was accelerated over a 24-week period in infected apoE−/− mice compared with control uninfected apoE−/− mice. Acceleration of atherosclerosis was reduced by antiviral drug administration. Histological analysis of the atheromatous plaques showed no difference between lesions of infected and control mice. Viral mRNA was present in the aortas of infected mice before lesion development on day 5 after infection. This suggests that the virus may initiate endothelial injury, which is believed to be an early event in the development of atherosclerosis. Therefore, the virus may play a direct role in atherosclerosis rather than be an “innocent bystander.”

Conclusions
—These data demonstrate that a γ-herpesvirus can accelerate atherosclerosis in the apoE−/− mouse. This study provides the first report of a murine model in which to study the causative role of herpesvirus infection in the development of atherosclerosis.
Molecular Pharmacology of the Sodium Channel Mutation D1790G Linked to the Long-QT Syndrome
Authors: Abriel H. , Wehrens X. H. T. , Benhorin J. , Kerem B. , Kass R. S.
Published: June 2012

Background
—Multiple mutations of
SCN5A
, the gene that encodes the human Na
+
channel α-subunit, are linked to 1 form of the congenital long-QT syndrome (LQT-3). D1790G (DG), an LQT-3 mutation of the C-terminal region of the Na
+
channel α-subunit, alters steady-state inactivation of expressed channels but does not promote sustained Na
+
channel activity. Recently, flecainide, but not lidocaine, has been found to correct the disease phenotype, delayed ventricular repolarization, in DG carriers.

Methods and Results
—To understand the molecular basis of this difference, we studied both drugs using wild-type (WT) and mutant Na
+
channels expressed in HEK 293 cells. The DG mutation conferred a higher sensitivity to lidocaine (EC
50
, WT=894 and DG=205 μmol/L) but not flecainide tonic block in a concentration range that is not clinically relevant. In contrast, in a concentration range that is therapeutically relevant, DG channels are blocked selectively by flecainide (EC
50
, WT=11.0 and DG=1.7 μmol/L), but not lidocaine (EC
50
, WT=318.0 and DG=176 μmol/L) during repetitive stimulation.

Conclusions
—These results (1) demonstrate that the DG mutation confers a unique pharmacological response on expressed channels; (2) suggest that flecainide use–dependent block of DG channels underlies its therapeutic effects in carriers of this gene mutation; and (3) suggest a role of the Na
+
channel α-subunit C-terminus in the flecainide/channel interaction.
Impact of Diabetes on Long-Term Prognosis in Patients With Unstable Angina and Non–Q-Wave Myocardial Infarction
Authors: Malmberg Klas , Yusuf Salim , Gerstein Hertzel C. , Brown Joanne , Zhao Feng , Hunt David , Piegas Leopoldo , Calvin James , Keltai Matyas , Budaj Andrzej , Investigators for the OASIS Registry
Published: June 2012

Background
—Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction.

Methods and Results
—Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non–Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%,
P
<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81;
P
<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease.

Conclusions
—Hospitalization for unstable angina or non–Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.
The Elusive Link Between LQT3 and Brugada Syndrome
Authors: Priori Silvia G. , Napolitano Carlo , Schwartz Peter J. , Bloise Raffaella , Crotti Lia , Ronchetti Elena
Published: June 2012

Background
—Defects of the
SCN5A
gene encoding the cardiac sodium channel are associated with both the LQT3 subtype of long-QT syndrome and Brugada syndrome (BS). The typical manifestations of long-QT syndrome (QT interval prolongation) and BS (ST segment elevation in leads V1 through V3) may coexist in the same patients, which raises questions about the actual differences between LQT3 and BS. Intravenous flecainide is the standard provocative test used to unmask BS in individuals with concealed forms of the disease, and oral flecainide has been proposed as a treatment option for LQT3 patients because it may shorten their QT interval.

Methods and Results
—We tested the possibility that in some LQT3 patients, flecainide might not only shorten the QT interval, but also produce an elevation of the ST segment. A total of 13 patients from 7 LQT3 families received intravenous flecainide using the protocol used for BS. As expected, QT, QTc, JT, and JTc interval shortening was observed in 12 of the 13 patients, and concomitant ST segment elevation in leads V1 through V3 (≥2 mm) was observed in 6 of the 13.

Conclusions
—The data demonstrate that flecainide may induce ST segment elevation in LQT3 patients, raising concerns about the safety of flecainide therapy and demonstrating the existence of an intriguing overlap between LQT3 and BS.
Inhibition of Restenosis With β-Emitting Radiotherapy
Authors: Raizner Albert E. , Oesterle Stephen N. , Waksman Ron , Serruys Patrick W. , Colombo Antonio , Lim Yean-Leng , Yeung Alan C. , van der Giessen Wim J. , Vandertie Lynn , Chiu Joseph K. , White Larry R. , Fitzgerald Peter J. , Kałuża Grzegorz L. , Ali Nadir M.
Published: June 2012

Background
—Intracoronary γ- and β-radiation have reduced restenosis in animal models. In the clinical setting, the effectiveness of β-emitters has not been studied in a broad spectrum of patients, particularly those receiving stents.

Methods and Results
—A prospective, randomized, sham-controlled study of intracoronary radiotherapy with the β-emitting
32
P source wire, using a centering catheter and automated source delivery unit, was conducted. A total of 105 patients with de novo (70%) or restenotic (30%) lesions who were treated by stenting (61%) or balloon angioplasty (39%) received 0 (control), 16, 20, or 24 Gy to a depth of 1 mm in the artery wall. Angiography at 6 months showed a target site late loss index of 11±36% in radiotherapy patients versus 55±30% in controls (
P
<0.0001). A low late loss index was seen in stented and balloon-treated patients and was similar across the 16, 20, and 24 Gy radiotherapy groups. Restenosis (≥50%) rates were significantly lower in radiotherapy patients at the target site (8% versus 39%;
P
=0.012) and at target site plus adjacent segments (22% versus 50%;
P
=0.018). Target lesion revascularization was needed in 5 radiotherapy patients (6%) and 6 controls (24%;
P
<0.05). Stenosis adjacent to the target site and late thrombotic events reduced the overall clinical benefit of radiotherapy.

Conclusions
—β-radiotherapy with a centered
32
P source is safe and highly effective in inhibiting restenosis at the target site after stent or balloon angioplasty. However, minimizing edge narrowing and late thrombotic events must be accomplished to maximize the clinical benefit of this modality.
Hydroxy-Methylglutaryl–Coenzyme A Reductase Inhibition Promotes Endothelial Nitric Oxide Synthase Activation Through a Decrease in Caveolin Abundance
Authors: Feron Olivier , Dessy Chantal , Desager Jean-Pierre , Balligand J.-L.
Published: June 2012

Background
—Hypercholesterolemia is causally associated with defects of endothelial nitric oxide (NO)–dependent vasodilation. Increased uptake of cholesterol by endothelial cells (ECs) upregulates the abundance of the structural protein caveolin-1 and impairs NO release through the stabilization of the inhibitory heterocomplex between caveolin-1 and endothelial NO synthase (eNOS). Therefore, we examined whether the hydroxy-methylglutaryl–coenzyme A reductase inhibitor atorvastatin modulates caveolin abundance, eNOS activity, and NO release through a reduction in endogenous cholesterol levels.

Methods and Results
—ECs were incubated with increasing doses of atorvastatin in the absence or in the presence of human LDL cholesterol (LDL-Chol) fractions in the presence of antioxidants. Our results show that atorvastatin (10 nmol/L to 1 μmol/L) reduced caveolin-1 abundance in the absence (−75%) and in the presence (−20% to 70%) of LDL-Chol. This was paralleled by a decreased inhibitory interaction between caveolin-1 and eNOS and a restoration and/or potentiation of the basal (+45%) and agonist-stimulated (+107%) eNOS activity. These effects were observed in the absence of changes in eNOS abundance and were reversed with mevalonate. In the presence of LDL-Chol, atorvastatin also promoted the agonist-induced association of eNOS and the chaperone Hsp90, resulting in the potentiation of eNOS activation.

Conclusions
—We provide biochemical and functional evidence that atorvastatin promotes NO production by decreasing caveolin-1 expression in ECs, regardless of the level of extracellular LDL-Chol. These findings highlight the therapeutic potential of inhibiting cholesterol synthesis in peripheral cells to correct NO-dependent endothelial dysfunction associated with hypercholesterolemia and possibly other diseases.
Local Delivery of Human Tissue Kallikrein Gene Accelerates Spontaneous Angiogenesis in Mouse Model of Hindlimb Ischemia
Authors: Emanueli Costanza , Minasi Alessandra , Zacheo Antonella , Chao Julie , Chao Lee , Salis Maria Bonaria , Straino Stefania , Tozzi Maria Grazia , Smith Robert , Gaspa Leonardo , Bianchini Giuseppe , Stillo Francesco , Capogrossi Maurizio C. , Madeddu Paolo
Published: June 2012

Background
—Human tissue kallikrein (HK) releases kinins from kininogen. We investigated whether adenovirus-mediated HK gene delivery is angiogenic in the context of ischemia.

Methods and Results
—Hindlimb ischemia, caused by femoral artery excision, increased muscular capillary density (
P
<0.001) and induced the expression of kinin B
1
receptor gene (
P
<0.05). Pharmacological blockade of B
1
receptors blunted ischemia-induced angiogenesis (
P
<0.01), whereas kinin B
2
receptor antagonism was ineffective. Intramuscular delivery of adenovirus containing the HK gene (Ad.CMV-cHK) enhanced the increase in capillary density caused by ischemia (969±32 versus 541±18 capillaries/mm
2
for control,
P
<0.001), accelerated blood flow recovery (
P
<0.01), and preserved energetic charge of ischemic muscle (
P
<0.01). Chronic blockade of kinin B
1
or B
2
receptors prevented HK-induced angiogenesis.

Conclusions
—HK gene delivery enhances the native angiogenic response to ischemia. Angiogenesis gene therapy with HK might be applicable to peripheral occlusive vascular disease.
Diet-Induced Hyperhomocysteinemia Exacerbates Neointima Formation in Rat Carotid Arteries After Balloon Injury
Authors: Morita Hiroyuki , Kurihara Hiroki , Yoshida Shigetaka , Saito Yuichiro , Shindo Takayuki , Oh-hashi Yoshio , Kurihara Yukiko , Yazaki Yoshio , Nagai Ryozo
Published: June 2012

Background
—Increasing evidence indicates that elevated plasma homocysteine levels are associated with an increased risk of atherosclerosis and endothelial dysfunction, although little specific information on the mechanisms responsible for the atherogenic effects of homocysteine or on the in vivo contribution made by hyperhomocysteinemia to atherosclerosis is currently available. Because homocysteine is known to exert a direct inhibitory effect on endothelial cell growth in vitro, we hypothesized that this effect contributes to the progression of atherosclerotic lesions initiated by endothelial damage caused by mechanical injury.

Methods and Results
—We prepared diet-induced hyperhomocysteinemic rats in which neointima formation after balloon injury to the common carotid artery was assessed. Moderate hyperhomocysteinemia (plasma homocysteine levels 3- to 4-fold higher than control) significantly exacerbated neointima formation. Oral administration of folate, which had a homocysteine-lowering effect, diminished neointima formation induced by moderate hyperhomocysteinemia. Furthermore, the attenuation of reendothelialization was shown in diet-induced hyperhomocysteinemic rats with Evans blue staining.

Conclusions
—Diet-induced hyperhomocysteinemia, even mild to moderate, exacerbates neointima formation after denuding injury, making hyperhomocysteinemia a likely risk factor for postangioplasty restenosis. It may be mediated through an inhibitory effect of homocysteine on reendothelialization. Homocysteine lowering with folate supplementation can effectively ameliorate the detrimental effects of moderate hyperhomocysteinemia. Clinical trials would seem to be warranted.
Ticlopidine Pretreatment Before Coronary Stenting Is Associated With Sustained Decrease in Adverse Cardiac Events
Authors: Steinhubl Steven R. , Ellis Stephen G. , Wolski Kathy , Lincoff A. Michael , Topol Eric J.
Published: June 2012

Background
—Platelet inhibition at the time of a percutaneous coronary intervention has consistently been shown to decrease the risk of thrombotic adverse events but not restenosis. The role of enhanced antiplatelet protection through pretreatment with the platelet ADP-receptor antagonist ticlopidine in preventing both the early and late complications of coronary stenting has not previously been explored.

Methods and Results
—In the Evaluation of Platelet IIb/IIIa Inhibitor for Stenting (EPISTENT) trial, ≈1600 patients were randomized to stenting with either placebo or abciximab in addition to aspirin and heparin. All stented patients also received ticlopidine after the procedure, but 58% of these patients were given ticlopidine before stenting at the discretion of the investigating physician. Among patients randomized to placebo, ticlopidine pretreatment was associated with a significant decrease in the incidence of the composite end point of death, myocardial infarction, or target vessel revascularization (TVR) at 1 year (adjusted hazard ratio, 0.73; 95% CI, 0.54 to 0.98;
P
=0.036). Ticlopidine pretreatment did not significantly influence the risk of death or myocardial infarction in patients randomized to abciximab. Controlling for patient characteristics and for the propensity of being on ticlopidine, Cox proportional hazards regression identified ticlopidine pretreatment as an independent predictor of the need for TVR at 1 year (hazard ratio, 0.62; 95% CI, 0.43 to 0.89;
P
=0.010) in both placebo-treated and abciximab-treated patients.

Conclusions
—In the EPISTENT trial, among patients randomized to stenting, starting ticlopidine before the percutaneous coronary intervention was associated with a significant decrease in the incidence of the 12-month composite end point for patients not receiving abciximab and the need for TVR among all patients.
Ribozyme-Mediated Inhibition of Rat Leukocyte-Type 12-Lipoxygenase Prevents Intimal Hyperplasia in Balloon-Injured Rat Carotid Arteries
Authors: Gu Jia-Li , Pei Hong , Thomas Lisa , Nadler Jerry L. , Rossi John J. , Lanting Linda , Natarajan Rama
Published: June 2012

Background
—12-Lipoxygenase (12-LO) products of arachidonate metabolism have growth and chemotactic effects in vascular smooth muscle cells. We have also recently demonstrated increased 12-LO mRNA and protein expression in the neointima of balloon-injured rat carotid arteries. In this study, we evaluated whether 12-LO activation plays a role in neointimal thickening in this rat model by using a specific ribozyme (Rz) directed to rat 12-LO.

Methods and Results
—We designed a chimeric DNA-RNA hammerhead Rz to cleave rat leukocyte-type 12-LO mRNA. This Rz dose-dependently cleaved a 166-nucleotide target 12-LO mRNA substrate in vitro and reduced 12-LO mRNA and protein expression in rat vascular smooth muscle cells. A control mutant Rz (MRz) with a point mutation in the catalytic site was inactive. To test the in vivo efficacy of the 12-LO Rz, the left common carotid arteries of rats were injured with a balloon catheter. The distal half of the injured arteries was treated with Rz or MRz mixed with lipofectin. The proximal half received only lipofectin. Twelve days after injury, intima-to-media ratios were significantly lower in the Rz-treated sections than in untreated sections from the same rat (0.742±0.16 versus 1.749±0.12,
P
<0.001). In contrast, the MRz had no significant effect.

Conclusions
—These results indicate the important role of the leukocyte-type 12-LO pathway in restenosis in response to injury.
Age-Dependent and Hypoxia-Related Differences in Myocardial Protection During Pediatric Open Heart Surgery
Authors: Imura H. , Caputo M. , Parry A. , Pawade A. , Angelini G. D. , Suleiman M.-S.
Published: June 2012

Background
—Current cardioplegic protection techniques used in pediatric cardiac surgery do not take into consideration age and cyanotic differences. The aim of the present work was to address this question by monitoring clinical outcome, myocardial metabolism, and reperfusion injury in pediatric patients protected by cold-crystalloid cardioplegia.

Methods and Results
—Fifty-eight patients (31 children and 27 infants) with or without hypoxic stress (cyanosis) undergoing open heart surgery with cold-crystalloid cardioplegia were included in the study. Clinical outcome measures assessed included inotropic and ventilatory support, intensive care, and hospital stay. Ischemia-induced changes in metabolism (adenine nucleotides, purines, lactate, and amino acids) were determined in ventricular biopsies collected at the beginning and end of ischemic time (cross-clamp time). Reperfusion injury was assessed by measuring postoperative serial release of troponin I. Evidence was observed of ischemic stress during cardioplegic arrest in children and infants as shown by significant changes in cellular metabolites. Compared with infants, children had significantly less reperfusion injury and better clinical outcome, and these factors were related to duration of ischemic time. Cyanosis did not influence outcome in infants, but cyanotic children showed worse reperfusion injury and clinical outcome than acyanotic children.

Conclusions
—Extent of myocardial protection with cold-crystalloid cardioplegia in pediatric open heart surgery is dependent on age and degree of cyanosis.
Electromechanical Mapping for Detection of Myocardial Viability in Patients With Ischemic Cardiomyopathy
Authors: Bøtker Hans Erik , Lassen Jens Flensted , Hermansen Flemming , Wiggers Henrik , Søgaard Peter , Kim Won Yong , Bøttcher Morten , Thuesen Leif , Pedersen Anders Kirstein
Published: June 2012

Background
—We evaluated the ability of electromechanical mapping of the left ventricle to distinguish between nonviable and viable myocardium in patients with ischemic cardiomyopathy.

Methods and Results
—Unipolar voltage amplitudes and local endocardial shortening were measured in 31 patients (mean±SD age, 62±8 years) with ischemic cardiomyopathy (ejection fraction, 30±9%). Dysfunctional regions, identified by 3D echocardiography, were characterized as nonviable when PET revealed matched reduction of perfusion and metabolism and as viable when perfusion was reduced or normal and metabolism was preserved. Mean unipolar voltage amplitudes and local shortening differed among normal, nonviable, and viable dysfunctional segments. Coefficient of variation for local shortening exceeded differences between groups and did not allow distinction between normal and dysfunctional myocardium. Optimum nominal discriminatory unipolar voltage amplitude between nonviable and viable dysfunctional myocardium was 6.5 mV, but we observed a great overlap between groups. Individual cutoff levels calculated as a percentage of electrical activity in normal segments were more accurate in the detection of viable dysfunctional myocardium than a general nominal cutoff level. The optimum normalized discriminatory value was 68%. Sensitivity and specificity were 78% for the normalized discriminatory value compared with 69% for the nominal value (
P
<0.02).

Conclusions
—Endocardial ECG amplitudes in patients with ischemic cardiomyopathy display a wide scatter, complicating the establishment of exact nominal values that allow distinction between viable and nonviable areas. Individual normalization of unipolar voltage amplitudes improves diagnostic accuracy. Electroanatomic mapping may enable identification of myocardial viability.
Gene Therapy With Extracellular Superoxide Dismutase Protects Conscious Rabbits Against Myocardial Infarction
Authors: Li Qianhong , Bolli Roberto , Qiu Yumin , Tang Xian-Liang , Guo Yiru , French Brent A.
Published: June 2012

Background
—Extracellular superoxide dismutase (Ec-SOD) may protect the heart against myocardial infarction (MI) because of its extended half-life and capacity to bind heparan sulfate proteoglycans on cellular surfaces. Accordingly, we used direct gene transfer to increase systemic levels of Ec-SOD and determined whether this gene therapy could protect against MI.

Methods and Results
—The cDNA for human Ec-SOD was incorporated into a replication-deficient adenovirus (Ad5/CMV/Ec-SOD). Injection of this virus produced a high level of Ec-SOD in the liver, which was redistributed to the heart and other organs by injection of heparin. Untreated rabbits (group I) underwent a 30-minute coronary occlusion and 3 days of reperfusion. For comparison, preconditioned rabbits (group II) underwent a sequence of six 4-minute-occlusion/4-minute-reperfusion cycles 24 hours before the 30-minute occlusion. Control-treated rabbits (group III) were injected intravenously with Ad5/CMV/nls-LacZ, and gene-therapy rabbits (group IV) were injected with Ad5/CMV/Ec-SOD 3 days before the 30-minute occlusion. Both groups treated with Ad5 received intravenous heparin 2 hours before the 30-minute occlusion. Infarct size (percent risk area) was similar in groups I (57±6%) and III (58±5%). Ec-SOD gene therapy markedly reduced infarct size to 25±4% (
P
<0.01, group IV versus group III), a protection comparable to that of the late phase of ischemic preconditioning (29±3%,
P
<0.01 group II versus group I).

Conclusions
—Direct gene transfer of the cDNA encoding membrane-bound Ec-SOD affords powerful cardioprotection, providing proof of principle for the effectiveness of antioxidant gene therapy against MI.
Selective α
v
β
3
-Receptor Blockade Reduces Macrophage Infiltration and Restenosis After Balloon Angioplasty in the Atherosclerotic Rabbit
Authors: Bishop Gregory G. , McPherson John A. , Sanders John M. , Hesselbacher Sean E. , Feldman Michael J. , McNamara Coleen A. , Gimple Lawrence W. , Powers Eric R. , Mousa Shaker A. , Sarembock Ian J.
Published: June 2012

Background
—α
v
β
3
-Integrin receptors are upregulated in atherosclerotic arteries and play a key role in smooth muscle cell and possibly inflammatory cell migration. We hypothesized that after balloon angioplasty (BA) of atherosclerotic arteries, selective inhibition of the α
v
β
3
-receptor by XT199, a small-molecule, non–peptide-selective α
v
β
3
-receptor antagonist, would reduce restenosis.

Methods and Results
—After induction of focal atherosclerosis, rabbits underwent femoral BA and received XT199 (2.5 mg/kg IV bolus plus 2.5 mg · kg
−1
· d
−1
IV; n=19) or vehicle (n=20) for 14 days. At 28 days after BA, the XT199 group had a larger lumen (0.75±0.26 versus 0.57±0.20 mm
2
,
P
=0.03) and a smaller neointimal area (0.49±0.18 versus 0.68±0.25 mm
2
,
P
=0.01) than the vehicle group. Angiographic analysis confirmed a 30% to 40% reduction in restenosis. Arteries harvested at 28 days after BA did not show a reduction in intima plus media smooth muscle cell content but did show a 50% reduction in macrophage cell density in the XT199 group (716±452 versus 1458±989 cells/mm
2
,
P
<0.006). Neovessel density at 28 days was also reduced (23±42 versus 58±46 vessel cross sections/mm
2
,
P
<0.02). Early after BA (ie, 3 to 7 days), there was a decrease in intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression, indicative of a reduction in vascular cell activation.

Conclusions
—Selective α
v
β
3
-receptor blockade for 14 days after BA in the focally atherosclerotic rabbit significantly reduced restenosis and limited macrophage infiltration and neovascularization in the vessel wall.
Serpin Protein CrmA Suppresses Hypoxia-Mediated Apoptosis of Ventricular Myocytes
Authors: Gurevich Rhonna M. , Regula Kelly M. , Kirshenbaum Lorrie A.
Published: June 2012

Background
—In this study, we ascertain whether caspase 8 activation and mitochondrial defects underlie apoptosis of ventricular myocytes during hypoxia. As an approach to circumvent the potential shortcomings surrounding the limited permeability and short half-life of the synthetic peptide inhibitors designed to block caspase activation, we constructed a replication-defective adenovirus encoding the serpin caspase inhibitor protein CrmA to ensure efficient and continual inhibition of caspase 8 activity during chronic hypoxia.

Methods and Results
—In contrast to normoxic cells, oxygen deprivation of postnatal ventricular myocytes for 24 hours resulted in a 9-fold increase (
P
<0.05) in apoptosis as determined by Hoechst 33258 staining and nucleosomal DNA laddering. Moreover, hypoxia provoked a 1.5-fold increase (
P
<0.01) in caspase 8–like activity. Furthermore, hypoxia provoked perturbations to mitochondria consistent with the mitochondrial death pathway, including permeability transition pore (PT) opening, loss of mitochondrial membrane potential (ΔΨ
m
), and cytochrome c release. Importantly, CrmA suppressed caspase 8 activity, PT pore changes, loss of ΔΨ
m
, and apoptosis but had no effect on hypoxia-mediated cytochrome c release. Furthermore, Bongkrekic acid, an inhibitor of PT pore, prevented hypoxia-induced PT pore changes, loss of ΔΨ
m
, and apoptosis but had no effect on hypoxia-mediated cytochrome c release.

Conclusions
—To our knowledge, we provide the first direct evidence for the operation of CrmA as an antiapoptotic factor in ventricular myocytes during prolonged durations of hypoxia. Furthermore, our data suggest that perturbations to mitochondria including PT pore changes and ΔΨ
m
loss are caspase-regulated events that appear to be separable from cytochrome c release.
Preload Induces Troponin I Degradation Independently of Myocardial Ischemia
Authors: Feng Jun , Schaus Benjamin J. , Fallavollita James A. , Lee Te-Chung , Canty John M.
Published: June 2012

Background
—Although global ischemia induces troponin I (TnI) degradation, regional ischemia does not. We hypothesized that this disparity is related to preload-induced proteolysis, which varies as a function of the amount of myocardium at risk of ischemia.

Methods and Results
—Isolated rat hearts were buffer-perfused at controlled levels of preload. Increasing preload to 25 mm Hg in the absence of ischemia produced pronounced TnI degradation (27 kDa versus 31 kDa bands: 16.4±3.6% versus 4.7±1.9% in immediately excised controls,
P
<0.05). TnI degradation could be blocked by preventing the activation of endogenous calpains with 25 μmol/L calpeptin (4.3±0.6%). This improved function, with left ventricular systolic pressure increasing from 103±4 mm Hg to 137±7 mm Hg (
P
<0.05). Eliminating elevations in preload after global ischemia-induced stunning also prevented TnI degradation.

Conclusions
—Calpain-mediated TnI proteolysis can be dissociated from stunning and arises from elevations in preload rather than ischemia. This raises the possibility that ongoing preload-induced TnI degradation could impair myocardial function long-term.
Selective Augmentation of Prostacyclin Production by Combined Prostacyclin Synthase and Cyclooxygenase-1 Gene Transfer
Authors: Shyue Song-Kun , Tsai May-Jywan , Liou Jun-Yang , Willerson James T. , Wu Kenneth K.
Published: June 2012

Background
—We tested the hypothesis that combined cyclooxygenase-1 (COX-1) and prostacyclin synthase (PGIS) gene transfer selectively augments prostacyclin production without a concurrent overproduction of other prostanoids.

Methods and Results
—ECV304 cells were transfected with bicistronic pCOX-1/PGIS versus pCOX-1 or pPGIS, and prostanoids were analyzed. Contrary to the high prostaglandin E
2
synthesis in pCOX-1 transfected cells, selective prostacyclin formation was noted with bicistronic plasmid transfection. Next, we determined the optimal ratio of Ad-COX-1 to Ad-PGIS by transfecting human umbilical vein endothelial cells with various titers of these 2 adenoviral constructs and determined the level of protein expression and prostanoid synthesis. Our results show that optimal ratios of adenoviral titers to achieve a large prostacyclin augmentation without overproduction of prostaglandin E
2
or F
2α
were 50 to 100 plaque forming units (pfu) of Ad-COX-1 to 50 pfu of Ad-PGIS per cell. A higher Ad-PGIS to Ad-COX-1 ratio caused a paradoxical decline in prostacyclin synthesis.

Conclusions
—Prostacyclin synthesis can be selectively augmented by cotransfecting endothelial cells with an optimal ratio of COX-1 to PGIS. Combined COX-1 and PGIS gene transfer has the potential for therapeutic augmentation of prostacyclin.
Echolucent Plaques Are Associated With High Risk of Ischemic Cerebrovascular Events in Carotid Stenosis
Authors: Mathiesen Ellisiv B. , Bønaa Kaare H. , Joakimsen Oddmund
Published: June 2012

Background
—The purpose of the study was to assess in a prospective design whether plaque morphology is associated with risk of ischemic stroke and other cerebrovascular events in subjects with carotid stenosis.

Methods and Results
—A total of 223 subjects with carotid stenosis (123 with 35% to 49% degree of stenosis, 100 with 50% to 99% stenosis) and 215 control subjects matched by age and sex who participated in a population health survey at baseline were followed up for 3 years. Plaque echogenicity was assessed by ultrasound at baseline and scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Forty-four subjects experienced ≥1 ischemic cerebrovascular events in the follow-up period. Plaque echogenicity, degree of stenosis, and white blood cell count were independent predictors of cerebrovascular events. The unadjusted relative risk for cerebrovascular events was 13.0 (95% CI 4.5 to 37.4) in subjects with echolucent plaques and 3.7 (95% CI 0.7 to 18.2) in subjects with echogenic plaques when subjects without stenosis were used as the reference. The adjusted relative risk for cerebrovascular events in subjects with echolucent plaques was 4.6 (95% CI 1.1 to 18.9), and there was a significant linear trend (
P
=0.015) for higher risk with increasing plaque echolucency. The adjusted relative risk for a 10% increase in the degree of stenosis was 1.2 (95% CI 1.04 to 1.4).

Conclusions
—Subjects with echolucent atherosclerotic plaques have increased risk of ischemic cerebrovascular events independent of degree of stenosis and cardiovascular risk factors. Subjects at high risk for ischemic vascular events may be identified by ultrasound assessment of plaque morphology.
Matrix-Dependent Mechanism of Neutrophil-Mediated Release and Activation of Matrix Metalloproteinase 9 in Myocardial Ischemia/Reperfusion
Authors: Lindsey Merry , Wedin Kyle , Brown Michael D. , Keller Christopher , Evans Alida J. , Smolen James , Burns Alan R. , Rossen Roger D. , Michael Lloyd , Entman Mark
Published: June 2012

Background
—A key component of reperfusion of myocardial infarction is an immediate inflammatory response, which enhances tissue repair. Matrix turnover is crucial to tissue repair, and matrix metalloproteinases (MMPs) are key enzymes involved in matrix degradation. The hypothesis tested is that one inflammation-based effector of tissue repair is the secretion and activation of MMP-9 by infiltrating neutrophils.

Methods and Results
—Cardiac lymph and tissue were assayed for latent and active MMP-2 and MMP-9 by zymography and immunochemistry. Dual-labeling immunofluorescence determined the cellular source of MMP-9 protein. Isolated canine neutrophils were incubated with preischemic and postischemic cardiac lymph in the presence and absence of collagen-fibronectin pads, and the supernatants were assayed for latent and active MMP-9. MMP-9 increased during the first hours of reperfusion in both lymph supernatants and myocardial extracts, and this increase was of neutrophil origin. MMP-9 in the cardiac lymph remained latent but was activatable. In contrast, MMP-9 in the myocardium was in both latent and active forms. In situ zymography demonstrated that activated MMP-9 surrounded the infiltrated neutrophils. When postischemic cardiac lymph was incubated with neutrophils in vitro, MMP-9 secretion and activation occurred only in the presence of a collagen-fibronectin substrate; preischemic cardiac lymph did not induce significant secretion or activation.

Conclusions
—Infiltrating neutrophils are an early source of MMP-9 after reperfusion, and a portion of MMP-9 in the myocardium is active. Infiltrating neutrophils may localize MMP-9 activation by secreting MMP-9 and as a source of activating proteases.
Impact of Sex and Gonadal Steroids on Prolongation of Ventricular Repolarization and Arrhythmias Induced by
I
K
-Blocking Drugs
Authors: Pham Thai V. , Sosunov Eugene A. , Gainullin Ravil Z. , Danilo Peter , Rosen Michael R.
Published: June 2012

Background
—Mechanisms for longer rate-corrected QT intervals and higher incidences of drug-induced torsade de pointes in women than in men are incompletely defined, although gonadal steroids are assumed to be important determinants of these differences.

Methods and Results
—We used microelectrode techniques to study isolated rabbit right ventricular endocardium from control male and female and castrated male (ORCH) and female (OVX) rabbits. Action potential duration to 30% repolarization (APD
30
) was significantly shorter in male than female and in ORCH than OVX at a cycle length of 500 ms. The
I
Ks
blocker chromanol 293B had no effect on APD in males or females. The
I
Kr
blocker dofetilide prolonged APD in female and ORCH more than in male and OVX. At 10
−
6
mol/L dofetilide (cycle length=1 second), the incidence of early afterdepolarizations was: female, 67%; ORCH, 56%; male, 40%; and OVX, 28%. Serum 17β-estradiol levels were unrelated to the effects of dofetilide, but as testosterone levels increased, the dofetilide effect to increase APD diminished, as did early afterdepolarization incidence.

Conclusions
—Sex-related differences in basal right ventricular endocardial AP configuration persist in castrated rabbits, suggesting that extragonadal factors contribute to the differences in ventricular repolarization. In this model, drugs that block
I
Kr
but not
I
Ks
prolong repolarization in a way that suggests that protection from excess prolongation in males is attributable to testosterone, whereas the risk of excess prolongation of repolarization in females is related to sex-determined factors in addition to estrogen.
Cell Cycle in Vasculoproliferative Diseases
Authors: Sriram Vissa , Patterson Cam
Published: June 2012

Abstract

—Atherosclerosis and restenosis of epicardial vessels are among the greatest challenges facing the clinical cardiologist, and phenotypic modulation and proliferation of smooth muscle cells are major components of the vasculoproliferative response. Proliferation is regulated by the interplay of regulatory proteins at checkpoints in the cell cycle that alter cellular growth. Activation of the cell cycle and the genetic control of its progression are final common pathways in this process. Investigators have postulated that cell-cycle inhibition using drugs and genetic or physical methods has the potential to reverse or prevent the vasculoproliferative process. The current challenge is to translate in vitro data demonstrating the efficacy of cell-cycle inhibition to clinical trials. At present, the steps that must be taken to meet this goal are (1) to design methods of delivery of these agents to specific sites, (2) to identify appropriate cellular targets to elicit cell-cycle arrest, and (3) to improve the therapeutic ratio by minimizing potential side effects. This review discusses current concepts of the cell cycle, target-regulating mechanisms, and possible interventions in vasculoproliferative diseases. We also discuss ongoing clinical trials that use antiproliferative agents in the hope of limiting the course of these diseases, as well as the promise that antiproliferative therapy holds in the coming decade.
PPARα Activators Inhibit Tissue Factor Expression and Activity in Human Monocytes
Authors: Marx Nikolaus , Mackman Nigel , Schönbeck Uwe , Yilmaz Nurcan , Hombach Vinzenz , Libby Peter , Plutzky Jorge
Published: June 2012

Background
—Tissue factor (TF), expressed on the surface of monocytes and macrophages in human atherosclerotic lesions, acts as the major procoagulant initiating thrombus formation in acute coronary syndromes. Peroxisome proliferator–activated receptor-α (PPARα), a nuclear receptor family member, regulates gene expression in response to certain fatty acids and fibric acid derivatives. Given that some of these substances reduce TF activity in patients, we tested whether PPARα activators limit TF responses in human monocytic cells.

Methods and Results
—Pretreatment of freshly isolated human monocytes or monocyte-derived macrophages with PPARα activators WY14643 and eicosatetraynoic acid (ETYA) led to reduced lipopolysaccharide (LPS)-induced TF activity in a concentration-dependent manner (maximal reduction to 43±8% with 250 μmol/L WY14643 [
P
<0.05, n=5] and to 42±12% with 30 μmol/L ETYA [
P
>0.05, n=3]). Two different PPARγ activators (15-deoxy
_Δ12,14
-prostaglandin J
2
and
BRL49653
) lacked similar effects. WY14643 also decreased tumor necrosis factor-α protein expression in supernatants of LPS-stimulated human monocytes. Pretreatment of monocytes with WY14643 inhibited LPS-induced TF protein and mRNA expression without altering mRNA half-life. Transient transfection assays of a human TF promoter construct in THP-1 cells revealed WY14643 inhibition of LPS-induced promoter activity, which appeared to be mediated through the inhibition of nuclear factor-κB but not to be due to reduced nuclear factor-κB binding.

Conclusions
—PPARα activators can reduce TF expression and activity in human monocytes/macrophages and thus potentially reduce the thrombogenicity of atherosclerotic lesions. These data provide new insight into how PPARα-activating fibric acid derivatives and certain fatty acids might influence atherothrombosis in patients with vascular disease.