bluuebunny/crossref_metadata_2025 huggingface dataset:
Prognosis in Women With Myocardial Ischemia in the Absence of Obstructive Coronary Disease
Authors: Johnson B. Delia , Shaw Leslee J. , Buchthal Steven D. , Bairey Merz C. Noel , Kim Hee-Won , Scott Katherine N. , Doyle Mark , Olson Marian B. , Pepine Carl J. , den Hollander Jan , Sharaf Barry , Rogers William J. , Mankad Sunil , Forder John R. , Kelsey Sheryl F. , Pohost Gerald M.
Published: June 2004

Background—

We previously reported that 20% of women with chest pain but without obstructive coronary artery disease (CAD) had stress-induced reduction in myocardial phosphocreatine–adenosine triphosphate ratio by phosphorus-31 nuclear magnetic resonance spectroscopy (abnormal MRS), consistent with myocardial ischemia. The prognostic implications of these findings are unknown.

Methods and Results—

Women referred for coronary angiography for suspected myocardial ischemia underwent MRS handgrip stress testing and follow-up evaluation. These included (1) n=60 with no CAD/normal MRS, (2) n=14 with no CAD/abnormal MRS, and (3) n=352 a reference group with CAD. Cardiovascular events were death, myocardial infarction, heart failure, stroke, other vascular events, and hospitalization for unstable angina. Cumulative freedom from events at 3 years was 87%, 57%, and 52% for women with no CAD/normal MRS, no CAD/abnormal MRS, and CAD, respectively (
P
<0.01). After adjusting for CAD and cardiac risk factors, a phosphocreatine–adenosine triphosphate ratio decrease of 1% increased the risk of a cardiovascular event by 4% (
P
=0.02). The higher event rate in women with no CAD/abnormal MRS was primarily due to hospitalization for unstable angina, which is associated with repeat catheterization and higher healthcare costs.

Conclusions—

Among women without CAD, abnormal MRS consistent with myocardial ischemia predicted cardiovascular outcome, notably higher rates of anginal hospitalization, repeat catheterization, and greater treatment costs. Further evaluation into the underlying pathophysiology and possible treatment options for women with evidence of myocardial ischemia but without CAD is indicated.
Gender-Related Differences in Acute Aortic Dissection
Authors: Nienaber Christoph A. , Fattori Rossella , Mehta Rajendra H. , Richartz Barbara M. , Evangelista Arturo , Petzsch Michael , Cooper Jeanna V. , Januzzi James L. , Ince Hüseyin , Sechtem Udo , Bossone Eduardo , Fang Jianming , Smith Dean E. , Isselbacher Eric M. , Pape Linda A. , Eagle Kim A.
Published: June 2004

Background—

Few data exist on gender-related differences in clinical presentation, diagnostic findings, management, and outcomes in acute aortic dissection (AAD).

Methods and Results—

Accordingly, we evaluated 1078 patients enrolled in the International Registry of Acute Aortic Dissection (IRAD) to assess differences in clinical features, management, and in-hospital outcomes between men and women. Of the patients enrolled in IRAD (32.1%) with AAD, 346 were women. Although less frequently affected by AAD (32.1% of AAD), women were significantly older and had more often presented later than men (
P
=0.008); symptoms of coma/altered mental status were more common, whereas pulse deficit was less common. Diagnostic imaging suggestive of rupture, ie, periaortic hematoma, and pleural or pericardial effusion were more commonly observed in women. In-hospital complications of hypotension and tamponade occurred with greater frequency in women, resulting in higher in-hospital mortality compared with men. After adjustment for age and hypertension, women with aortic dissection die more frequently than men (OR, 1.4,
P
=0.04), predominantly in the 66- to 75-year age group. Moreover, surgical outcome was worse in women than men (
P
=0.013); type A dissection in women was associated with a higher surgical mortality of 32% versus 22% in men despite similar delay, surgical technique, and hemodynamics.

Conclusions—

Our analysis provides insights into gender-related differences in AAD with regard to clinical characteristics, management, and outcomes; important diagnostic and therapeutic implications may help shed light on aortic dissection in women to improve their outcomes.
Sudden Death in Familial Polymorphic Ventricular Tachycardia Associated With Calcium Release Channel (Ryanodine Receptor) Leak
Authors: Lehnart Stephan E. , Wehrens Xander H.T. , Laitinen Päivi J. , Reiken Steven R. , Deng Shi-Xiang , Cheng Zhenzhuang , Landry Donald W. , Kontula Kimmo , Swan Heikki , Marks Andrew R.
Published: June 2004

Background—

Familial polymorphic ventricular tachycardia (FPVT) is characterized by exercise-induced arrhythmias and sudden cardiac death due to missense mutations in the cardiac ryanodine receptor (RyR2), an intracellular Ca
2+
release channel required for excitation-contraction coupling in the heart.

Methods and Results—

Three RyR2 missense mutations, P2328S, Q4201R, and V4653F, which occur in Finnish families, result in similar mortality rates of ≈33% by age 35 years and a threshold heart rate of 130 bpm, above which exercise induces ventricular arrhythmias. Exercise activates the sympathetic nervous system, increasing cardiac performance as part of the fight-or-flight stress response. We simulated the effects of exercise on mutant RyR2 channels using protein kinase A (PKA) phosphorylation. All 3 RyR2 mutations exhibited decreased binding of calstabin2 (FKBP12.6), a subunit that stabilizes the closed state of the channel. After PKA phosphorylation, FPVT-mutant RyR2 channels showed a significant gain-of-function defect consistent with leaky Ca
2+
release channels and a significant rightward shift in the half-maximal inhibitory Mg
2+
concentration (IC
50
). Treatment with the experimental drug JTV519 enhanced binding of calstabin2 to RyR2 and normalized channel function.

Conclusions—

Sympathetic activation during exercise induces ventricular arrhythmias above a threshold heart rate in RyR2 mutation carriers. Simulating the downstream effects of the sympathetic activation by PKA phosphorylation of RyR2 channels containing these FPVT missense mutations produced a consistent gain-of-function defect. RyR2 function and calstabin2 depletion were rescued by JTV519, suggesting stabilization of the RyR2 channel complex may represent a molecular target for the treatment and prevention of exercise-induced arrhythmias and sudden death in these patients. (Circulation. 2004;109:3208-3214.)
Nonsteroidal Antiinflammatory Drugs and the Risk of Myocardial Infarction in the General Population
Authors: García Rodríguez Luis A. , Varas-Lorenzo Cristina , Maguire Andrew , González-Pérez Antonio
Published: June 2004

Background—

Nonsteroidal antiinflammatory drugs (NSAIDs) are reversible inhibitors of cyclooxygenase (COX)-1 and COX-2. Whether transient and incomplete COX-1 inhibition with NSAIDs other than aspirin will translate into clinical cardioprotection is unclear. Some reports suggest that concurrent aspirin and ibuprofen might be associated with lower cardioprotection than aspirin alone because of a pharmacodynamic interaction.

Methods and Results—

—We conducted a cohort study with a nested case-control analysis. Overall, 4975 cases of acute myocardial infarction (MI) and death from coronary heart disease (CHD) were identified (January 1997 to December 2000) in the UK. A total of 20 000 controls were randomly sampled, and frequency was matched to cases by age, sex, and calendar year. The incidence rate was 5.0 per 1000 person-years. The multivariate-adjusted OR for current NSAID use compared with nonuse was 1.07 (95% CI, 0.95 to 1.20). Treatment duration or daily dose did not change the results. The effect was similar among patients free of CHD history (1.04; 95% CI, 0.90 to 1.20) and patients with previous history (1.12; 95% CI, 0.91 to 1.38). Estimates for individual NSAIDs were all comparable, with no major effect on the risk of acute MI. Naproxen was associated with an OR of 0.89 (95% CI, 0.64 to 1.24). The OR of aspirin and concurrent NSAIDs use was 1.10 (95% CI, 0.89 to 1.37) compared with aspirin alone. We observed the same result when analyzing ibuprofen and aspirin taken concomitantly.

Conclusions—

This study could not demonstrate any detectable risk reduction of NSAIDs on the occurrence of MI. Our results do not support the existence of a clinically meaningful interaction between aspirin and NSAIDs, including ibuprofen.
Tissue Doppler Imaging Is Superior to Strain Rate Imaging and Postsystolic Shortening on the Prediction of Reverse Remodeling in Both Ischemic and Nonischemic Heart Failure After Cardiac Resynchronization Therapy
Authors: Yu Cheuk-Man , Fung Jeffrey Wing-Hong , Zhang Qing , Chan Chi-Kin , Chan Yat-Sun , Lin Hong , Kum Leo C.C. , Kong Shun-Ling , Zhang Yan , Sanderson John E.
Published: June 2004

Background—

A number of noninvasive techniques have been used to predict the effectiveness of cardiac resynchronization therapy (CRT) in heart failure patients, in particular left ventricular (LV) reverse remodeling. This study compared the relative predictive values of tissue Doppler imaging (TDI) and strain-rate imaging (SRI) parameters for LV reverse remodeling in patients who received CRT and examined for potential differences in ischemic (n=22) and nonischemic (n=32) heart failure.

Methods and Results—

TDI and SRI were performed at baseline and 3-month follow-up. Eighteen parameters of intraventricular and interventricular asynchrony based on the time to peak myocardial contraction (Ts) and time to peak strain rate (Tsr) were compared, along with postsystolic shortening (PSS). Reverse remodeling with reduction of LV end-diastolic and end-systolic volumes and gain in ejection fraction (all
P
<0.001) was observed in the whole study population. The standard deviation of Ts of 12 LV segments (Ts-SD) is the most powerful predictor of reverse remodeling in both the ischemic (
r
=−0.65,
P
<0.001) and nonischemic (
r
=−0.79,
P
<0.001) groups. The PSS of 12 LV segments was a good predictor only for the nonischemic (
r
=−0.64,
P
<0.001) but not the ischemic (
r
=0.32,
P
=NS) group. However, parameters of SRI and interventricular asynchrony failed to predict reverse remodeling. By multiple regression analysis, independent parameters included Ts-SD in both groups (
P
<0.005) and PSS of 12 LV segments in the nonischemic group (
P
=0.03). The area of the receiver operating characteristic curve was largest for Ts-SD (0.94; CI=0.88 to 1.00).

Conclusions—

Ts-SD is the most powerful predictor of LV reverse remodeling and was consistently useful for ischemic and nonischemic heart failure. However, PSS is useful only for nonischemic pathogenesis, whereas the role of SRI parameters was not supported by the present study.
Electrophysiological Findings in Adolescents With Atrial Fibrillation Who Have Structurally Normal Hearts
Authors: Nanthakumar Kumaraswamy , Lau Yung R. , Plumb Vance J. , Epstein Andrew E. , Kay G. Neal
Published: June 2004

Background—

Atrial fibrillation (AF) is uncommon in children, and its mechanisms are unknown. This study describes the electrophysiological findings in children and adolescents with AF and the outcome of catheter ablation.

Methods and Results—

Nine adolescents with symptomatic, lone AF who failed antiarrhythmic drug therapy were evaluated. All patients had ECG-documented AF and underwent invasive electrophysiological testing. Intracardiac mapping was performed to determine the site of spontaneous onset of AF and rapidly firing atrial foci. Only the triggering focus was targeted for ablation or isolation. The patients’ mean age was 15.9±3.3 (range, 8 to 19 years). The most common finding was rapid, irregular atrial tachycardias in the region of the pulmonary veins (n=5), left atrium (n=2), or crista terminalis (n=3). One patient had foci in both the pulmonary veins and crista terminalis. The cycle lengths ranged from 108 to 280 ms. Catheter ablation was acutely successful in 8 patients (88.9%), whereas 1 patient with multiple left atrium foci was treated with the surgical maze operation. Over a mean of 35±22 months, 7 patients (77.8%) were arrhythmia free on no medications, while AF recurred in 2 patients who are controlled on antiarrhythmic medications. Two patients with tachycardia-induced cardiomyopathy had resolution of their left ventricular dysfunction after ablation.

Conclusions—

AF in adolescents with structurally normal hearts is usually due to foci in the pulmonary veins, crista terminalis, or left atrium. These foci usually induce irregular atrial tachycardias. Catheter ablation of the foci is effective in eliminating recurrent AF.
Functional Tetrahydrobiopterin Synthesis in Human Platelets
Authors: Franscini Nicola , Bachli Esther B. , Blau Nenad , Fischler Manuel , Walter Roland B. , Schaffner Andreas , Schoedon Gabriele
Published: June 2004

Background—

Previous studies have provided evidence for the importance of platelet-derived nitric oxide (NO) for the regulation of hemostasis. Tetrahydrobiopterin (BH
4
) is an essential cofactor and regulator of NO synthase activity in the vasculature; however, it is as yet unknown whether platelets dispose over a functional BH
4
synthesis.

Methods and Results—

We quantified mRNA expression of genes involved in BH
4
synthesis, measured enzymatic activities, and determined intraplatelet levels of pteridines in platelets from healthy volunteers and from patients treated for prolonged periods of time with glucocorticoids. Freshly isolated platelets from healthy volunteers show functional BH
4
synthesis, as evidenced by the presence of mRNA species and enzymatic activity of GTP cyclohydrolase I (GTPCH), 6-pyruvoyl tetrahydropterin synthase, and sepiapterin reductase. Biopterin was the major intraplatelet pteridine, whereas no neopterin was found. mRNA expression and enzymatic activity of GTPCH were undetectably low in platelets that had been stored for 5 days, and no pteridines were found in these platelets. Freshly isolated platelets from patients treated with glucocorticoids had decreased mRNA expression and activity of GTPCH compared with platelets from healthy volunteers.

Conclusions—

Human platelets dispose over a functional de novo BH
4
synthesis. Furthermore, our results indicate the potential of external factors, eg, prolonged storage or glucocorticoid therapy, to significantly affect BH
4
synthesis within platelets. Together, these findings offer new insights into the biology and pathobiology of platelet function in humans.
N-Terminal Pro-Brain Natriuretic Peptide on Admission Has Prognostic Value Across the Whole Spectrum of Acute Coronary Syndromes
Authors: Galvani Marcello , Ottani Filippo , Oltrona Luigi , Ardissino Diego , Gensini Gian Franco , Maggioni Aldo P. , Mannucci Pier Mannuccio , Mininni Nicola , Prando Maria Domenica , Tubaro Marco , Vernocchi Arialdo , Vecchio Carlo
Published: June 2004

Background—

The prognostic value of natriuretic peptide elevations in patients with acute coronary syndromes (ACS) is still incompletely defined. We measured N-terminal pro-brain natriuretic peptide (NT-proBNP) on admission in patients with ACS and ECG evidence of myocardial ischemia.

Methods and Results—

The NT-proBNP was measured at a median time of 3 hours after symptom onset in 1756 patients. The outcome measure was death at 30 days, which occurred in 113 patients (6.4%). The median NT-proBNP level was 353 ng/L (107 to 1357 ng/L). Compared with the lowest quartile, patients in the second, third, and fourth quartiles had a relative risk of subsequent death of 2.94 (95% CI, 1.15 to 7.52), 5.32 (95% CI, 2.19 to 12.91), and 11.5 (95% CI, 4.90 to 26.87), respectively. The NT-proBNP was independently associated with death in a logistic regression model, which included clinical variables, ECG, and troponin T in patients either with (OR of highest versus lowest quartile, 7.0; 95% CI, 1.9 to 25.6) or without (OR of highest versus lowest quartile, 4.1; 95% CI, 1.1 to 14.6) persistent ST-segment elevation. NT-proBNP was also an independent predictor of severe heart failure.

Conclusions—

The measurement of NT-proBNP on admission improves the early risk stratification of patients with ACS, suggesting the need for the development of targeted therapeutic strategies.
Inhibition of Platelet Adherence to Mononuclear Cells by α-Tocopherol
Authors: Murohara Toyoaki , Ikeda Hisao , Otsuka Yoritaka , Aoki Mika , Haramaki Nobuya , Katoh Atsushi , Takajo Yoshinori , Imaizumi Tsutomu
Published: June 2004

Background—

Platelet-leukocyte interaction is an early important event for thrombogenesis, and this process is mainly mediated by P-selectin on platelets. Although α-tocopherol has been shown to inhibit thrombotic disorders, the effect of α-tocopherol on platelet P-selectin expression and platelet-leukocyte interaction is little known.

Methods and Results—

We examined whether α-tocopherol inhibited human platelet P-selectin expression and platelet-leukocyte interaction. α-Tocopherol (50 to 500 μg/mL) inhibited thrombin-induced or phorbol 12-myristate 13-acetate (PMA)-induced P-selectin expression on platelets. α-Tocopherol suppressed platelet–mononuclear cell (MNC) interaction, platelet aggregation, and platelet protein kinase C (PKC) activity stimulated with either PMA (100 nmol/L) or thrombin. Inhibitory actions of α-tocopherol against the platelet functions were mimicked by staurosporine, a selective PKC inhibitor. After oral supplementation of α-tocopherol (300 mg/d for 3 weeks) in healthy subjects, thrombin-mediated or PMA-mediated P-selectin expression, platelet-MNC interaction, and platelet aggregation ex vivo were suppressed.

Conclusions—

α-Tocopherol inhibited P-selectin expression on human platelets and thereby attenuated platelet-MNC interactions, which were mediated at least in part by the inhibition of intraplatelet PKC activity. These actions of α-tocopherol on platelet functions provide new insights into the antithromboatherogenic properties of α-tocopherol.
Soluble Fibrin Is the Main Mediator of
Staphylococcus aureus
Adhesion to Platelets
Authors: Niemann Silke , Spehr Nicola , Van Aken Hugo , Morgenstern Eberhard , Peters Georg , Herrmann Mathias , Kehrel Beate E.
Published: June 2004

Background—

Infective endocarditis (IE) caused by
Staphylococcus aureus
is associated with significant morbidity and mortality rates. Platelets play a dual role as adhesive cells forming associates with bacteria as well as specialized inflammatory cells. The specific role of the various factors involved in bacteria-platelet association has not yet been fully elucidated.

Methods and Results—

We observed a dramatic increase in the capability to bind
S aureus
when platelets were activated with thrombin (from 5% to 30%,
P
<0.001). To pinpoint platelet-binding sites involved in the interaction, platelets from knockout mice and from patients with selective inherited deficiency of membrane proteins or of granules were used. CD36, GPIIb/IIIa, and P-selectin were excluded as receptors for
S aureus
. Platelets from patients with α-δ–storage pool disease and Gray platelet syndrome indicate the requirement of α-granule contents. Platelet activation by ADP did not promote platelet–
S aureus
associate formation, although these platelets were covered with bound fibrinogen. Only small numbers of associates between fibrinogen-covered bacteria and ADP-activated platelets were observed. Formation of fibrin alone was also not sufficient to induce association. Only when fibrin formation and platelet activation occurred together were large numbers of associates formed (
P
<0.001). A potential receptor for fibrin on
S aureus
is clumping factor A. Addition of thrombospondin-1 to control platelets increased the number of associates (
P
=0.02).

Conclusions—

Soluble fibrin but not fibrinogen is the main mediator of platelet–
S aureus
association. In addition, platelet activation and the release of α-granule contents, particularly thrombospondin-1, is a requirement for platelet–
S aureus
association.
Regression of Carotid Atherosclerosis by Control of Postprandial Hyperglycemia in Type 2 Diabetes Mellitus
Authors: Esposito Katherine , Giugliano Dario , Nappo Francesco , Marfella Raffaele
Published: June 2004

Background—

Postprandial hyperglycemia may be a risk factor for cardiovascular disease. We compared the effects of two insulin secretagogues, repaglinide and glyburide, known to have different efficacy on postprandial hyperglycemia, on carotid intima-media thickness (CIMT) and markers of systemic vascular inflammation in type 2 diabetic patients.

Methods and Results—

We performed a randomized, single-blind trial on 175 drug-naive patients with type 2 diabetes mellitus (93 men and 82 women), 35 to 70 years of age, selected from a population of 401 patients who participated in an epidemiological analysis assessing the relation of postprandial hyperglycemia to surrogate measures of atherosclerosis. Eighty-eight patients were randomly assigned to receive repaglinide and 87 patients to glyburide, with a titration period of 6 to 8 weeks for optimization of drug dosage and a subsequent 12-month treatment period. The effects of repaglinide (1.5 to 12 mg/d) and glyburide (5 to 20 mg/d) on CIMT were compared by using blinded, serial assessments of the far wall. After 12 months, postprandial glucose peak was 148±28 mg/dL in the repaglinide group and 180±32 mg/dL in the glyburide group (
P
<0.01). HbA
1c
showed a similar decrease in both groups (−0.9%). CIMT regression, defined as a decrease of >0.020 mm, was observed in 52% of diabetics receiving repaglinide and in 18% of those receiving glyburide (
P
<0.01). Interleukin-6 (
P
=0.04) and C-reactive protein (
P
=0.02) decreased more in the repaglinide group than in the glyburide group. The reduction in CIMT was associated with changes in postprandial but not fasting hyperglycemia.

Conclusions—

Reduction of postprandial hyperglycemia in type 2 diabetic patients is associated with CIMT regression.
Unexpected Severe Calcification After Transplantation of Bone Marrow Cells in Acute Myocardial Infarction
Authors: Yoon Young-Sup , Park Jong-Seon , Tkebuchava Tengiz , Luedeman Corinne , Losordo Douglas W.
Published: June 2004

Background—

There has been a rapid increase in the number of clinical trials using unselected bone marrow (BM) cells or the mononuclear fraction of BM cells for treating ischemic heart diseases. Thus far, no significant deleterious effects or complications have been reported in any studies using BM-derived cells for treatment of various cardiac diseases.

Methods and Results—

Seven-week-old female Fisher-344 rats underwent surgery to induce acute myocardial infarction and were randomized into 3 groups of 16 rats, each receiving intramyocardial injection of either 7×10
5
DiI-labeled total BM cells (TBMCs), the same number of DiI-labeled, clonally expanded BM multipotent stem cells, or the same volume of phosphate-buffered saline in the peri-infarct area. Echocardiography 2 weeks after cell transplantation indicated intramyocardial calcification in 4 of 14 surviving rats (28.5%) in the TBMC group. Histological examination with hematoxylin and eosin staining and von Kossa staining confirmed the presence of extensive intramyocardial calcification. Alkaline phosphatase staining revealed strong positivity surrounding the calcified area suggestive of ongoing osteogenic activity. Fluorescent microscopic examination revealed that acellular calcific areas were surrounded by DiI-labeled TBMCs, suggesting the direct involvement of transplanted TBMCs in myocardial calcification. In contrast, in hearts receiving equal volumes of saline or BM multipotent stem cells delivered in the same manner, there was no evidence of calcification.

Conclusions—

These results demonstrate that direct transplantation of unselected BM cells into the acutely infarcted myocardium may induce significant intramyocardial calcification.
Platelet-Derived Growth Factor Receptor Transactivation Mediates the Trophic Effects of Angiotensin II In Vivo
Authors: Kelly Darren J. , Cox Alison J. , Gow Renae M. , Zhang Yuan , Kemp Bruce E. , Gilbert Richard E.
Published: June 2004

In addition to the modulation of vascular tone, angiotensin II (Ang II) has growth factor–like effects in vascular tissue. The mechanisms whereby Ang II mediates these trophic actions are incompletely understood but are thought to include effects on systemic blood pressure, stimulation of transforming growth factor-β (TGF-β) expression, and transactivation of growth factor receptor kinases. To investigate the role of platelet-derived growth factor receptor (PDGFR) transactivation in mediating the growth factor–like effects of Ang II we administered Ang II (200 ng/kg per minute) or saline to male Sprague-Dawley rats by osmotic minipump for 12 days and treated with imatinib mesylate, an inhibitor of the PDGFR tyrosine kinase. In addition to systolic blood pressure elevation, Ang II infusion led to increased vascular weight, media:lumen ratio, matrix expansion, and overexpression of TGF-β mRNA in mesenteric arteries. Without affecting blood pressure or PDGF ligand expression, imatinib attenuated the changes in vessel morphology but further increased TGF-β mRNA. Western blot analysis of mesenteric arterial tissue demonstrated the presence of the β- but not the α-isoform of PDGFR. Phosphorylation of PDGFR-β was increased by Ang II in vascular smooth muscle cells, and this was inhibited by imatinib. The findings of attenuation of vascular hypertrophy and matrix deposition by imatinib indicate that transactivation of the PDGFR in vivo contributes to the growth factor–like effects of Ang II, independent of its hemodynamic effects or its ability to induce TGF-β gene expression.
Avian Precardiac Endoderm/Mesoderm Induces Cardiac Myocyte Differentiation in Murine Embryonic Stem Cells
Authors: Rudy-Reil Diane , Lough John
Published: June 2004

The ability to regenerate damaged myocardium with tissue derived from embryonic stem (ES) cells is currently undergoing extensive investigation. As a prerequisite to transplantation therapy, strategies must be developed to induce ES cells to the cardiac phenotype. Toward this end, cues from mechanisms of embryonic induction have been exploited, based on previous findings that anterior lateral endoderm (precardiac endoderm) from gastrulation-stage chick embryos potently induces cardiac myocyte differentiation in both precardiac and nonprecardiac mesoderm. Hypothesizing that avian precardiac endoderm acting as feeder/inducer cells would induce high percentage conversion of murine ES (mES) cells into cardiac myocytes, it was observed that the majority (≈ 65%) of cocultured ES cell-derived embryoid bodies (EBs) were enriched in cardiac myocytes and exhibited rhythmic contractions. By contrast, mouse EBs cultured alone, or on feeder layers of mouse embryonic fibroblasts or avian nonprecardiac posterior endoderm, contained only 7% to 16% cardiac myocytes while exhibiting a relatively low incidence (<10%) of beating. When mES cells were cocultured with a bilayer of explanted precardiac endoderm/mesoderm, the incidence of rhythmically contractile EBs increased to 100%. To verify that the rhythmically contractile cells were derived from murine ES cells, cell-free medium conditioned by avian precardiac endoderm/mesoderm was used to induce myocyte differentiation in a mES cell-line containing a nuclear LacZ reporter marker gene under control of the cardiac-specific α-myosin heavy chain promoter, resulting in rhythmic contractility in 92% of EBs in which the majority of cells (average=86%) were identified as cardiac myocytes. The inductive efficacy of medium conditioned by avian precardiac endoderm/mesoderm may provide an opportunity to biochemically define factors that induce cardiac myocyte differentiation in ES cells. The full text of this article is available online at http://circres.ahajournals.org.
Endothelial PAS Domain Protein 1 Gene Promotes Angiogenesis Through the Transactivation of Both Vascular Endothelial Growth Factor and Its Receptor, Flt-1
Authors: Takeda Norihiko , Maemura Koji , Imai Yasushi , Harada Tomohiro , Kawanami Daiji , Nojiri Takefumi , Manabe Ichiro , Nagai Ryozo
Published: June 2004

Endothelial PAS domain protein 1 (EPAS1) is a basic-helix-loop-helix/PAS domain transcription factor that is expressed preferentially in vascular endothelial cells. EPAS1 shares high homology with hypoxia-inducible factor-1α (HIF-1α) and is reported to transactivate vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), and Tie2 promoters. In this study, we analyzed the role of EPAS1 in the process of angiogenesis. Using microarray technology, we looked for target genes regulated by EPAS1 in vascular endothelial cells. A total of 130 genes were upregulated by EPAS1, including fms-like tyrosine kinase-1 (Flt-1). Reporter analysis using human Flt-1 promoter and gel mobility shift assays showed that the heterodimer of EPAS1 and aryl hydrocarbon receptor nuclear translocator binds directly to HIF-1-binding site upstream of Flt-1 promoter and transactivates it. Small interfering RNA targeted to EPAS1 but not HIF-1α attenuated desferrioxamine-induced Flt-1 mRNA expression, thus EPAS1 is thought to play an essential role in hypoxic induction of Flt-1 gene. Furthermore, using mouse wound healing models, we demonstrated that adenovirus-mediated delivery of EPAS1 gene significantly induced the expression of VEGF, Flt-1, Flk-1, and Tie2 mRNA at the wound site and promoted mature angiogenesis. The proportion of the number of mural cells in newly formed vessels was significantly higher in EPAS1-treated wound area than VEGF-treated area. In conclusion, EPAS1 promotes Flt-1 gene expression and induces mRNA expression of VEGF, Flk-1, and Tie2, leading to enhancement of mature angiogenesis in vivo. Thus, EPAS1 may contribute to the construction of mature vessels by modulating the coordinated expressions of VEGF, Flt-1, Flk-1, and Tie2.
Signal Transducer and Activator of Transcription 3 Is Required for Myocardial Capillary Growth, Control of Interstitial Matrix Deposition, and Heart Protection From Ischemic Injury
Authors: Hilfiker-Kleiner Denise , Hilfiker Andres , Fuchs Martin , Kaminski Karol , Schaefer Arnd , Schieffer Bernhard , Hillmer Anja , Schmiedl Andreas , Ding Zhaoping , Podewski Edith , Podewski Eva , Poli Valeria , Schneider Michael D. , Schulz Rainer , Park Joon-Keun , Wollert Kai C. , Drexler Helmut
Published: June 2004

The transcription factor signal transducer and activator of transcription 3 (STAT3) participates in a wide variety of physiological processes and directs seemingly contradictory responses such as proliferation and apoptosis. To elucidate its role in the heart, we generated mice harboring a cardiomyocyte-restricted knockout of STAT3 using Cre/loxP-mediated recombination. STAT3-deficient mice developed reduced myocardial capillary density and increased interstitial fibrosis within the first 4 postnatal months, followed by dilated cardiomyopathy with impaired cardiac function and premature death. Conditioned medium from STAT3-deficient cardiomyocytes inhibited endothelial cell proliferation and increased fibroblast proliferation, suggesting the presence of paracrine factors attenuating angiogenesis and promoting fibrosis in vitro. STAT3-deficient mice showed enhanced susceptibility to myocardial ischemia/reperfusion injury and infarction with increased cardiac apoptosis, increased infarct sizes, and reduced cardiac function and survival. Our study establishes a novel role for STAT3 in controlling paracrine circuits in the heart essential for postnatal capillary vasculature maintenance, interstitial matrix deposition balance, and protection from ischemic injury and heart failure.
Paradoxical cAMP-Induced Lung Endothelial Hyperpermeability Revealed by
Pseudomonas aeruginosa
ExoY
Authors: Sayner Sarah L. , Frank Dara W. , King Judy , Chen Hairu , VandeWaa John , Stevens Troy
Published: June 2004

Mammalian transmembrane adenylyl cyclases synthesize a restricted plasmalemmal cAMP pool that is intensely endothelial barrier protective. Bacteria have devised mechanisms of transferring eukaryotic factor–dependent adenylyl cyclases into mammalian cells.
Pseudomonas aeruginosa
ExoY is one such enzyme that catalyzes cytosolic cAMP synthesis, with unknown function.
Pseudomonas aeruginosa
genetically modified to introduce only the ExoY toxin elevated cAMP 800-fold in pulmonary microvascular endothelial cells over 4 hours, whereas a catalytically deficient (ExoY
K81M
) strain did not increase cAMP. ExoY-derived cAMP was localized to a cytosolic microdomain not regulated by phosphodiesterase activity. In contrast to the barrier-enhancing actions of plasmalemmal cAMP, the ExoY cytosolic cAMP pool induced endothelial gap formation and increased the filtration coefficient in the isolated perfused lung. These findings collectively illustrate a previously unrecognized mechanism of hyperpermeability induced by rises in cytosolic cAMP.
Apolipoprotein D and Platelet-Derived Growth Factor-BB Synergism Mediates Vascular Smooth Muscle Cell Migration
Authors: Leung Wesley C.Y. , Lawrie Allan , Demaries Sandra , Massaeli Hamid , Burry Andrea , Yablonsky Shmuel , Sarjeant Jennifer M. , Fera Euridiki , Rassart Eric , Pickering J. Geoffrey , Rabinovitch Marlene
Published: June 2004

We identified apolipoprotein (apo)D in a search for proteins upregulated in a posttranscriptional manner similar to fibronectin in motile smooth muscle cells (SMCs). To address the function of apoD in SMCs, we cloned a partial apoD cDNA from ovine aortic (Ao) SMCs using RT-PCR. We documented a 2.5-fold increase in apoD protein but no increase in apoD mRNA in Ao SMCs 48 hours after a multiwound migration assay (
P
<0.01). Confocal microscopy revealed prominent perinuclear and trailing edge expression of apoD in migrating SMCs but not in the confluent monolayer. Stimulation of Ao SMCs with 10 ng/mL platelet-derived growth factor (PDGF)-BB increased apoD protein expression (
P
<0.05). Moreover, PDGF-BB–stimulated migration of human pulmonary artery SMCs was suppressed by knock-down of apoD using RNAi. Stable overexpression of apoD in Ao SMCs cultured in 10% fetal bovine serum promoted random migration by 62% compared with vector-transfected cells (
P
<0.01). Overexpression of apoD or addition of exogenous apoD to a rat aortic SMC line (A10) stimulated their migration in response to a subthreshold dose of PDGF-BB (
P
<0.05). This was unrelated to increased phosphorylation of ERK1/2 or of phospholipase C-γ1, but correlated with enhanced Rac1 activation. This study shows that apoD can be expressed or taken up by SMCs and can regulate their motility in response to growth factors.
Hypertension Caused by Angiotensin II Infusion Involves Increased Superoxide Production in the Central Nervous System
Authors: Zimmerman Matthew C. , Lazartigues Eric , Sharma Ram V. , Davisson Robin L.
Published: June 2004

Hypertension caused by angiotensin II (Ang II) infusion is associated with oxidative stress in the peripheral vasculature and kidney. The role of redox mechanisms in the central nervous system (CNS), a tissue known to be pivotal in Ang II–dependent hypertension, has not been investigated. We recently identified superoxide (O
2
·−
) in the brain as a key signaling intermediate in the transient pressor response elicited by acute injection of Ang II directly into the CNS. Here we tested the hypothesis that hypertension caused by chronic systemic infusion of Ang II is mediated by a central neurogenic mechanism involving O
2
·−
. Infusion of Ang II (600 ng · kg
−1
· min
−1
) over a 2-week period in mice caused a gradually developing hypertension that was correlated with marked elevations in O
2
·−
production specifically in the subfornical organ (SFO), a brain region lying outside the blood–brain barrier and known to be a primary sensor for blood-borne Ang II. Adenoviral-mediated delivery of cytoplasmically targeted superoxide dismutase (SOD) selectively to this site prevented the hypertension and the increased O
2
·−
production, whereas gene transfer of SOD targeted to the extracellular matrix had no effect. These data suggest that increased intracellular O
2
·−
production in the SFO is critical in the development of Ang II–induced hypertension.
Differential Modulation of L-type Ca
2+
Current by SR Ca
2+
Release at the T-Tubules and Surface Membrane of Rat Ventricular Myocytes
Authors: Brette Fabien , Sallé Laurent , Orchard Clive H.
Published: June 2004

We have characterized modulation of
I
Ca
by Ca
2+
at the t-tubules (ie, in control cells) and surface sarcolemma (ie, in detubulated cells) of cardiac ventricular myocytes, using the whole-cell patch clamp technique to record
I
Ca
.
I
Ca
inactivation was significantly slower in detubulated cells than in control cells (27.1±7.8 ms, n=22, versus 16.4±7.9 ms, n=22;
P
<0.05). In atrial myocytes, which lack t-tubules,
I
Ca
inactivation was not changed by the treatment used to produce detubulation. In the presence of ryanodine or BAPTA, or when Ba
2+
was used as the charge carrier, the rate of inactivation was not significantly different in control and detubulated cells. Frequency-dependent facilitation occurred in control cells but not in detubulated cells, and was abolished by ryanodine. These results suggest that Ca
2+
released from the SR has a greater effect on
I
Ca
in the t-tubules than at the surface sarcolemma. This does not appear to be due to differences in local Ca
2+
release from the SR, because the gain of Ca
2+
release was not significantly different in control and detubulated cells. These data suggest that the t-tubules are a key site for the regulation of transsarcolemmal Ca
2+
flux by Ca
2+
release from the SR; this could play a role in altered Ca
2+
homeostasis in pathological conditions. The full text of this article is available online at http://circres.ahajournals.org.
Endothelial Nitric Oxide Synthase Regulates Microlymphatic Flow via Collecting Lymphatics
Authors: Hagendoorn Jeroen , Padera Timothy P. , Kashiwagi Satoshi , Isaka Naohide , Noda Fatima , Lin Michelle I. , Huang Paul L. , Sessa William C. , Fukumura Dai , Jain Rakesh K.
Published: June 2004

Functional interactions between the initial and collecting lymphatics, as well as the molecular players involved, remain elusive. In this study, we assessed the influence of nitric oxide (NO) on lymphatic fluid velocity and flow, using a mouse tail model that permits intravital microscopy and microlymphangiography. We found that NO synthase (NOS) inhibition decreased lymphatic fluid velocity in the initial lymphatics, without any effect on their morphology. Using the same model, we found a similar effect in
eNOS
−/−
mice and in mice treated with a selective endothelial NOS (eNOS) inhibitor. Next, we uncoupled the superficial initial lymphatics from the deeper collecting lymphatics by ligating the latter and found that lymphatic fluid velocity in NOS-inhibited mice became equal to that in control animals. Surprisingly, lymphatic fluid velocity was significantly increased after ligating the collecting lymphatics, and there was a concomitant increase in injection rate and mean lymphatic vessel diameter. Our results provide the first in vivo evidence that eNOS affects function of the whole microlymphatic system and that it is regulated via the collecting lymphatics.
Short-Term Effects of Practice With Trunk Restraint on Reaching Movements in Patients With Chronic Stroke
Authors: Michaelsen Stella M. , Levin Mindy F.
Published: June 2004

Background and Purpose—In prehension tasks with objects placed within arm’s reach, patients with hemiparesis caused by stroke use excessive trunk movement to compensate for arm motor impairments. Compensatory trunk movements may improve motor function in the short term but may limit arm recovery in the long term. Previous studies showed that restriction of trunk movements during reach-to-grasp movements results in immediate increases in active arm joint ranges and improvement in interjoint coordination. To evaluate the potential of this technique as a therapeutic intervention, we compared the effects of short-term reach-to-grasp training (60-trial training session) with and without physical trunk restraint on arm movement patterns in patients with chronic hemiparesis.

Methods—A total of 28 patients with hemiparesis were assigned to 2 groups: 1 group practiced reach-to-grasp movements during which compensatory movement of the trunk was prevented by a harness (trunk restraint), and the second group practiced the same task while verbally instructed not to move the trunk (control). Kinematics of reaching and grasping an object placed within arm’s length were recorded before, immediately after, and 24 hours after training.

Results—The trunk restraint group used more elbow extension, less anterior trunk displacement, and had better interjoint coordination than the control group after training, and range of motion was maintained 24 hours later in only the trunk restraint group.

Conclusions—Restriction of compensatory trunk movements during practice may lead to greater improvements in reach-to-grasp movements in patients with chronic stroke than practice alone, and longer-term effects of this intervention should be evaluated.
Hyperhomocysteinemia, Low Folate and Vitamin B
12
Concentrations, and Methylene Tetrahydrofolate Reductase Mutation in Cerebral Venous Thrombosis
Authors: Cantu Carlos , Alonso Elisa , Jara Aurelio , Martínez Leticia , Ríos Camilo , Fernández María de los Angeles , Garcia Irma , Barinagarrementeria Fernando
Published: June 2004

Background and Purpose—

Elevated plasma levels of homocysteine are associated with an increased risk of deep-vein thrombosis. Through a case–control study, we examined the potential association among homocysteine, folate and vitamin B
12
levels, and the common C677→T mutation in the
methylene tetrahydrofolate reductase
(
MTHFR
) gene in patients with cerebral venous thrombosis (CVT).

Methods—

Forty-five patients with CVT and 90 control subjects were studied. Plasma levels of homocysteine (fasting and after methionine load), folate, and vitamin B
12
were measured. Genotyping of the
MTHFR
gene was also performed. The estimated risk of CVT associated with hyperhomocysteinemia, low vitamin levels, and
MTHFR
mutation were expressed as odds ratio (OR) and its 95% CI (crude and after adjusting by other independent variables).

Results—

The adjusted OR for CVT associated with high (>90th percentile) fasting levels of homocysteine was 4.6 (1.6 to 12.8). The association between low plasma folate values (<10th percentile) and presence of CVT was 3.5 (1.2 to 10.0) after adjustment for confounding factors. There was a higher frequency of
MTHFR
mutation in patients with CVT (22% versus 10%), but it was not statistically significant (
P
=0.098). Patients with
MTHFR
mutation and low folate levels presented the highest homocysteine levels.

Conclusions—

High plasma concentrations of homocysteine and low plasma folate levels were associated with an increased risk of CVT in this population in which low socioeconomic conditions and deficient nutritional status may contribute to its relatively high incidence.
Diagnostic Impact of Transcranial Color-Coded Real-Time Sonography With Echo Contrast Agents for Hyperperfusion Syndrome After Carotid Endarterectomy
Authors: Fujimoto Shigeru , Toyoda Kazunori , Inoue Tooru , Hirai Yuko , Uwatoko Takeshi , Kishikawa Kazuhiro , Yasumori Kotaro , Ibayashi Setsuro , Iida Mitsuo , Okada Yasushi
Published: June 2004

Background and Purpose—

The purpose of the present study was to evaluate availability of transcranial color-coded real-time sonography (TCCS) to detect hyperperfusion after carotid endarterectomy (CEA).

Methods—

This prospective study included 105 consecutive patients who underwent CEA for severe carotid stenosis. TCCS with echo contrast agents was performed serially to evaluate flow velocity of the middle cerebral artery (MCA). Regional cerebral blood flow (rCBF) and vasodilatory capacity of the MCA territory were evaluated using single-photon emission computed tomography. We compared the changes in MCA flow velocity with rCBF.

Results—

Using echo contrast agents, we could evaluate the MCA flow in 95 (90%) of 105 patients. Twelve patients showed hyperperfusion syndrome. Changes in the MCA mean flow velocity (MFV) before and 4 days after CEA were significantly correlated with those in rCBF (
r
=0.48;
P
<0.0001). An increase of >50% in MCA MFV was observed within 4 days after CEA in all 12 patients with hyperperfusion syndrome. Multivariate analysis revealed that reduced vasodilatory capacity (odds ratio, 0.14; 95% CI, 0.04 to 0.46) was an independent risk factor for a 1.5-fold increase in the MFV of MCA ipsilateral to CEA.

Conclusions—

Findings of a 1.5-fold increase in the MCA MFV can accurately identify those patients with high risk of developing post-CEA hyperperfusion syndrome. TCCS with echo contrast agents is available for the evaluation of hyperperfusion after CEA.
Soluble Thrombomodulin and Brain Infarction
Authors: Olivot Jean-Marc , Labreuche Julien , Aiach Martine , Amarenco Pierre
Published: June 2004

Background and Purpose—

Increased soluble thrombomodulin (sTM) concentration has been associated with recurrent coronary events, whereas in one prospective study it predicted fewer first-ever coronary events. One study found no relationship between brain infarction (BI) and sTM levels. Among all subjects of the Étude du Profil Génétique de l’Infarctus Cérébral (GENIC) cohort and those free of previous vascular history, we investigated the relationship between sTM level and BI risk, and among cases, its relationship with BI prognosis.

Methods—

Patients with BI (n=492) were consecutively recruited from 12 centers. Hospital controls without a history of stroke (n=492) were individually matched for age, sex, and center. Blood samples were collected after hospitalization. Determination of sTM levels was centralized in a single laboratory.

Results—

Soluble TM concentration significantly increased with age and hypertensive status, but was similar in cases and controls. With analyses restricted to 278 pairs of subjects with no previous vascular history, sTM concentration >59.6 μg/L (second and third tertiles compared with the first) was associated with fewer first-ever BI (adjusted odds ratio of 0.56 (95% CI, 0.35 to 0.89;
P
=0.014). Among the cases, increased sTM concentration was associated with a higher death rate after a median follow-up of 5.2 (1.4 to 6.4) years. The adjusted hazard ratio per 1 SD of sTM concentration increase (34.2 μg/L) was 1.19 (95% CI, 1.02 to 1.39;
P
=0.028).

Conclusions—

Increased sTM concentration may be protective against BI in subjects with no previous vascular disease, whereas it may predict a fatal outcome in patients who have already had a BI. Consequently, sTM levels should be interpreted according to vascular history.