bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscarinic (M) Receptors in Coronary Circulation
Authors: Lamping Kathryn G. , Wess Jürgen , Cui Yinghong , Nuno Daniel W. , Faraci Frank M.
Published: May 2004

Objective—

Determining the role of specific muscarinic (M) receptor subtypes mediating responses to acetylcholine (ACh) has been limited by the specificity of pharmacological agents. Deletion of the gene for M
5
receptors abolished response to ACh in cerebral blood vessels but did not affect dilation of coronary arteries. The goal of this study was to determine the M receptors mediating responses to ACh in coronary circulation using mice deficient in M
2
or M
3
receptors (M
2
−/−, M
3
−/−, respectively).

Methods and Results—

Coronary arteries from respective wild-type, M
2
−/−, or M
3
−/− mice were isolated, cannulated, and pressurized. Diameter was measured with video microscopy. After preconstriction with U46619, ACh produced dose-dependent dilation of coronary arteries that was similar in wild-type and M
2
−/− mice. In contrast, dilation of coronary arteries from M
3
−/− mice to ACh was reduced by ≈80% compared with wild type. The residual response to ACh was atropine insensitive. Relaxation of coronary arteries to other stimuli was similar in M
2
−/− and M
3
−/− mice. Similar results were obtained in aorta rings.

Conclusion—

These findings provide the first direct evidence that relaxation to ACh in coronary circulation is mediated predominantly by activation of M
3
receptors.
Basic Fibroblast Growth Factor–Induced Endothelial Proliferation and NO Synthesis Involves Inward Rectifier K
+
Current
Authors: Scharbrodt Wolfram , Kuhlmann Christoph Rüdiger Wolfram , Wu Yongijan , Schaefer Christian Alexander , Most Astrid Kerstin , Backenköhler Ulrich , Neumann Thomas , Tillmanns Harald , Waldecker Bernd , Erdogan Ali , Wiecha Johannes
Published: May 2004

Objectives—

Inward rectifier K
+
currents (K
ir
) determine the resting membrane potential and thereby modulate essential Ca
2+
-dependent pathways, like cell growth and synthesis of vasoactive agents in endothelial cells. Basic fibroblast growth factor (bFGF) acts as a vasodilatator and angiogenic factor. Therefore, we investigated the effect of bFGF on K
ir
and assessed the role in proliferation and nitric oxide (NO) formation of endothelial cells.

Methods and Results—

Using the patch-clamp technique, we found characteristic K
ir
in human umbilical cord vein endothelial cells (HUVEC), which were dose-dependently blocked by barium (10 to 100 μmol/L). Perfusion with bFGF (50 ng/mL) caused a significant increase of K
ir
, which was blocked by 100 μmol/L barium (n=18,
P
<0.01). The bFGF-induced HUVEC proliferation was significantly inhibited when using 50 to 100 μmol/L barium (n=6;
P
<0.01). NO production was examined using a cGMP radioimmunoassay. bFGF caused a significant increase of cGMP levels (n=10;
P
<0.05), which were blocked by barium.

Conclusions—

Modulation of K
ir
plays an important role in bFGF-mediated endothelial cell growth and NO formation.
Cyclophilin A Is a Proinflammatory Cytokine that Activates Endothelial Cells
Authors: Jin Zheng-Gen , Lungu Andreea O. , Xie Liang , Wang Meng , Wong Chelsea , Berk Bradford C.
Published: May 2004

Objective—

Cyclophilin A (CyPA) is an abundant intracellular protein that is considered to be the main target of the immunosuppressive drug cyclosporine A. We and others showed that CyPA is secreted from smooth muscle cells and macrophages in response to oxidative stress and lipopolysaccharide, suggesting a role for CyPA in inflammation. We therefore studied the proinflammatory effects of CyPA on vascular endothelium.

Methods and Results—

Because atherosclerosis is an inflammatory disease, we studied expression of CyPA in atherosclerotic plaques from the ApoE−/− mouse. Using immunohistochemistry, we showed that CyPA was highly expressed in these plaques. Because endothelial cells (EC) are important mediators of inflammation, we next studied the ability of CyPA to activate EC. Human recombinant CyPA activated mitogen-activated protein kinases, including ERK1/2, JNK, and p38 in cultured human umbilical vein EC. CyPA also stimulated IκB-α phosphorylation and NF-κB activation, and induced expression of adhesion molecules including E-selectin and vascular cell adhesion molecule-1. Furthermore, the combination of CyPA and cycloheximide induced EC apoptosis similar to the proapoptotic effect of tumor necrosis factor-α.

Conclusions—

Our data indicate that CyPA has proinflammatory effects on EC and may play an important role in the pathogenesis of inflammatory diseases, such as atherosclerosis.
Should Progestins Be Blamed for the Failure of Hormone Replacement Therapy to Reduce Cardiovascular Events in Randomized Controlled Trials?
Authors: Koh Kwang Kon , Sakuma Ichiro
Published: May 2004

Many observational studies and experimental and animal studies have demonstrated that estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) (estrogen plus progestin) significantly reduces the risk of coronary heart disease. Nonetheless, recent randomized controlled trials demonstrated some trends toward an increased risk of cardiovascular events rather than a reduction of risk. Recently, both the HRT and ERT arms of the Women’s Health Initiative (WHI) study were terminated early because of an increased/no incidence of invasive breast cancer, increased incidence of stroke, and increased trend/no protective effects of cardiovascular disease. We discuss the controversial effects of HRT and ERT on cardiovascular system and provide a hypothesis that the failure of HRT and ERT in reducing the risk of cardiovascular events in postmenopausal women might be because of the stage of their atherosclerosis at the time of initiation of HRT or ERT.
Deciphering Regulatory Patterns of Inflammatory Gene Expression From Interleukin-1—Stimulated Human Endothelial Cells
Authors: Mayer Herbert , Bilban Martin , Kurtev Vladislav , Gruber Florian , Wagner Oswald , Binder Bernd R. , de Martin Rainer
Published: May 2004

Objective—

Endothelial cells comprise a key component of the inflammatory response. We set out to obtain a comprehensive overview of the immediate-early to early gene expression program of interleukin-1 (IL-1)–stimulated endothelial cells and to identify novel transcription factors and regulatory elements.

Methods and Results—

Human umbilical vein endothelial cells (HUVECs) were stimulated with IL-1 for 0, 0.5, 1, 2.5, and 6 hours and analyzed using Affymetrix U133 microarrays. A total of 137 genes were found to be regulated >4-fold, including 18 transcription factors. The expression of selected genes was confirmed by real-time polymerase chain reaction. Cluster analysis was performed in order to group genes according to their expression profiles. To identify novel transcription factor–binding sites, the corresponding promoters were extracted from databases and analyzed for regulatory elements that were over-represented in specific clusters. Several potentially novel DNA binding sites were identified, and one was shown to specifically bind an IL-1–inducible protein from HUVEC.

Conclusions—

These results demonstrate that in the early phase after stimulation, IL-1 evokes a complex gene expression program that includes positive but also negative (feedback) regulators of diverse endothelial cell functions. Furthermore, the identification of a new promoter regulatory element demonstrates the feasibility of the bioinformatics-driven approach to discover novel regulatory mechanisms.
Intracellular Cholesterol Transport
Authors: Soccio Raymond E. , Breslow Jan L.
Published: May 2004

Intracellular cholesterol transport is essential for the maintenance of cholesterol homeostasis. Many aspects of cholesterol metabolism are well-known, including its synthesis in the endoplasmic reticulum, its extracellular transport in plasma lipoproteins, its uptake by the low-density lipoprotein receptor, and its regulation of SREBP and LXR transcription factors. These fundamental pathways in cholesterol metabolism all rely on its proper intracellular distribution among subcellular organelles and the plasma membrane. Transport involving the ER and endosomes is essential for cholesterol synthesis, uptake, and esterification, whereas cholesterol catabolism by enzymes in mitochondria and ER generates steroids, bile acids, and oxysterols. Cholesterol is a highly hydrophobic lipid that requires specialized transport in the aqueous cytosol, involving either vesicles or nonvesicular mechanisms. The latter includes hydrophobic cavity transporters such as StAR-related lipid transfer (START) proteins. Molecular understanding of intracellular cholesterol trafficking has lagged somewhat behind other aspects of cholesterol metabolism, but recent advances have defined some transport pathways and candidate proteins. In this review, we discuss cholesterol transport among specific intracellular compartments, emphasizing the relevance of these pathways to cholesterol homeostasis.
DC Electric Fields Induce Distinct Preangiogenic Responses in Microvascular and Macrovascular Cells
Authors: Bai Huai , McCaig Colin D. , Forrester John V. , Zhao Min
Published: May 2004

Objective—Electrical stimulation induces significant angiogenesis in vivo. We have shown recently that electrical stimulation induces directional migration, reorientation, and elongation of macrovascular endothelial cells. Because angiogenesis occurs mainly in the microvasculature, we have extended this observation to include human microvascular endothelial cells (HMEC-1s) and compared the responses with that of vascular fibroblasts and smooth muscle cells and human umbilical vein endothelial cells.

Methods and Results—Four types of vascular cells were cultured in electric fields (EFs). Dynamic cell behaviors were recorded and analyzed with an image analyzer. EFs of 150 to 400 mV/mm induced directed migration, reorientation, and elongation of all the vascular cells. HMEC-1s showed the greatest directional migration (migration rate of 11 μm/h and directedness of 0.35 at 200 mV/mm). Most intriguingly, HMEC-1s migrated toward the cathode, whereas the other cell types migrated toward the anode.

Conclusions—Endothelial cells derived from angiogenic microvascular as opposed to nonangiogenic macrovascular tissues were more responsive to electrical stimulation. This intriguing directional selectivity indicates that a DC electrical signal as a directional cue may be able to play a role in the spatial organization of vascular structure.
Angiotensin II Stimulates the Release of Interleukin-6 and Interleukin-8 From Cultured Human Adipocytes by Activation of NF-κB
Authors: Skurk Thomas , van Harmelen Vanessa , Hauner Hans
Published: May 2004

Objective—

Several proinflammatory cytokines including IL-6 and IL-8 are produced by human adipocytes, but it is still unclear how this process is regulated. Angiotensin (Ang) II, which is also produced by adipocytes, might play a role as a regulator. In the present study, we investigated the effect of Ang II on the production of IL-6 and IL-8 in in vitro differentiated human adipocytes.

Methods and Results—

Isolation of preadipocytes and differentiation of these cells into adipocytes, Real-time quantitative reverse-transcriptase polymerase chain reaction, Western-blot, enzyme-linked immunosorbent assay, and electromobility shift assay. Ang II-stimulated IL-6 and IL-8 mRNA expression and protein release in a time- and concentration-dependent way. This action of Ang II was completely blocked by the NF-κB-blocker Bay 117082 and the AT
1
blocker candesartan, but only partially by the AT
2
-blocker PD 123 319. Incubation of adipocytes with Ang II resulted in an increased phosphorylation of the p65 subunit of NF-κB and an increased translocation of NF-κB to the nucleus.

Conclusion—

Ang II stimulates IL-6 and IL-8 production and release from human adipocytes by a NF-κB-dependent pathway. This proinflammatory action of Ang II seems to be mediated by the AT
1
and less by the AT
2
receptor subtype.
Small GTP-Binding Protein Ral Is Involved in cAMP-Mediated Release of von Willebrand Factor From Endothelial Cells
Authors: Rondaij Mariska G. , Sellink Erica , Gijzen Karina A. , ten Klooster Jean Paul , Hordijk Peter L. , van Mourik Jan A. , Voorberg Jan
Published: May 2004

Objective—

von Willebrand factor (vWF) is synthesized by endothelial cells and stored in specialized vesicles called Weibel-Palade bodies (WPBs). Recently, we have shown that the small GTP-binding protein Ral is involved in thrombin-induced exocytosis of WPBs. In addition to Ca
2+
-elevating secretagogues such as histamine and thrombin, release of WPB is also observed after administration of cAMP-raising substances such as epinephrine and vasopressin. In the present study, we investigated whether Ral is also involved in cAMP-mediated vWF release.

Methods and Results—

Activation of Ral was observed 15 to 20 minutes after stimulation of endothelial cells with epinephrine, forskolin, or dibutyryl-cAMP. A cell-permeable peptide comprising the carboxy-terminal part of the Ral protein reduced both thrombin-induced and epinephrine-induced vWF secretion supporting a crucial role for Ral in this process. Furthermore, inhibition of protein kinase A by H-89 resulted in a marked reduction of vWF release and greatly diminished levels of GTP-Ral on stimulation with epinephrine. Activation of Ral was independent of the activation of Epac, a cAMP-regulated exchange factor for the small GTPases Rap1 and Rap2.

Conclusions—

These results suggest that protein kinase A-dependent activation of Ral regulates cAMP-mediated exocytosis of WPB in endothelial cells.
Differential Effects of Green Tea–Derived Catechin on Developing Versus Established Atherosclerosis in Apolipoprotein E–Null Mice
Authors: Chyu Kuang-Yuh , Babbidge Stephanie M. , Zhao Xiaoning , Dandillaya Ram , Rietveld Anton G. , Yano Juliana , Dimayuga Paul , Cercek Bojan , Shah Prediman K.
Published: May 2004

Background—

Oxidative stress has been implicated in vascular injury and atherogenesis, and antioxidant treatment has shown favorable results in preclinical studies. Despite this, antioxidant therapy has failed to show benefit in clinical trials. Failure of antioxidants in clinical trials may be partly because such therapy is started after atherosclerosis is already well established, whereas the benefits in animal models may be results from early initiation of antioxidants while atherosclerosis is still evolving.

Methods and Results—

To test this hypothesis, we evaluated the effect of epigallocatechin gallate (EGCG), the main antioxidant derived from green tea, on evolving and established atherosclerotic lesions in hypercholesterolemic apolipoprotein E–null mice. Established native aortic atherosclerotic lesions and evolving atherosclerotic lesions produced by periadventitial cuff injury to carotid arteries were assessed in mice after 21 and 42 days of treatment with daily intraperitoneal injections of EGCG (10 mg/kg) or PBS. EGCG treatment resulted in an increase in the antioxidant capacity in local vascular tissue and systemic circulation and reduced vascular smooth muscle cell proliferation and redox-sensitive gene activation in vitro. EGCG reduced cuff-induced evolving atherosclerotic plaque size at 21 and 42 days by 55% and 73%, respectively, compared with PBS treatment (
P
<0.05). Conversely, EGCG had no effect on established lesions in the aortic sinuses or the rest of the aorta.

Conclusions—

Our data suggest that antioxidant EGCG differentially reduces evolving atherosclerotic lesions without influencing established atherosclerosis in the apolipoprotein E–null mice.
Early Morning Attenuation of Endothelial Function in Healthy Humans
Authors: Otto Maria E. , Svatikova Anna , Barretto Rodrigo Bellio de Mattos , Santos Simone , Hoffmann Michal , Khandheria Bijoy , Somers Virend
Published: May 2004

Background—

Cardiovascular events such as myocardial infarction, sudden death, and stroke have a peak incidence in the early hours after waking. The mechanisms involved in this circadian variation are not clear. Endothelial dysfunction is associated with increased risk for cardiovascular events. We tested the hypothesis that endothelial function is reduced in the early morning, around the time of waking, compared with measurements obtained both before sleep and later in the day in healthy humans.

Methods and Results—

We studied 30 subjects (19 men, 11 women; mean age, 41.6 years). All participants underwent polysomnography to exclude obstructive sleep apnea or other sleep disorders. Brachial artery flow–mediated endothelium-dependent vasodilation (FMD) and endothelium–independent dilation (non-FMD) were measured on 3 different occasions: before subjects went to sleep (9
pm
), the next morning immediately after waking (6
am
), and during the late morning 5 hours after waking (11
am
). All subjects had normal sleep with good sleep efficiency of 84±2%. Compared with before sleep, FMD decreased markedly in the early morning after waking and recovered by late morning (9
pm
, 7.5±1%; 6
am
, 4.4±0.7%; 11
am
, 7.7±1%;
P
=0.02). Non-FMD was similar for the 3 periods of observation (9
pm
, 17.3±1.6%; 6
am
, 17.2±1.3%; 11
am
, 18.5±1.7%).

Conclusions—

FMD is blunted in the early morning in healthy subjects. Decreased endothelial function in the early morning may have implications for our understanding of the morning peak in cardiac and vascular events.
Endothelial Function Predicts Future Development of Coronary Artery Disease
Authors: Bugiardini Raffaele , Manfrini Olivia , Pizzi Carmine , Fontana Fiorella , Morgagni Gianluigi
Published: May 2004

Background—

The prognosis for women with chest pain and angiographically normal coronary arteries is believed to be totally benign. Previous studies, however, did not account for the delay of a decade or so in the development of coronary artery disease that women may experience.

Methods and Results—

This study assessed long-term follow-up of 42 women with de novo angina, evidence of reversible myocardial perfusion defects on SPECT, and normal coronary angiograms. At recruitment, all women underwent endothelial function testing (intracoronary acetylcholine) during catheterization. Patients were followed up for >10 years. Angiography was repeated at the end of the follow-up in 37 patients. At recruitment, 22 patients developed diffuse vasoconstriction during acetylcholine in the absence of identifiable focal coronary spasm (acetylcholine-positive group). The remaining 20 patients showed vasodilation (acetylcholine-negative group). At the end of follow-up, in the acetylcholine-positive group, 1 patient developed cardiac death, 13 still complained of chest pain, and 8 had remission of symptoms. In the acetylcholine-negative group, all patients showed complete resolution of chest pain beginning 6 to 36 months after baseline assessment. Angiography showed development of coronary artery disease in the 13 symptomatic patients in the acetylcholine-positive group.

Conclusions—

In women with angiographically normal-appearing coronary arteries, persistence of chest pain over the years often relates to development of coronary artery disease. Endothelial dysfunction in a setting of normal coronary arteries is a sign of future development of atherosclerosis.
Relaxin Is an Independent Risk Factor Predicting Death in Male Patients With End-Stage Kidney Disease
Authors: Hocher Berthold , Ziebig Reinhard , Krause Rolfdieter , Asmus Gernot , Neumayer Hans -H , Liefeldt Lutz , Stasch Johannes-Peter
Published: May 2004

Background—

Patients with end-stage kidney disease (ESKD) have a reduced life expectancy mainly as the result of cardiovascular diseases. Relaxin has been implicated in the pathogenesis of cardiovascular diseases. We analyzed the impact of relaxin on death in patients with ESKD.

Methods and Results—

Patients (n =245; 122 women, 123 men) on long-term hemodialysis were followed for 1140 days for death. Blood samples for analysis of relaxin, C-reactive protein, Troponin T, cholesterol, HDL, brain natriuretic peptide, and albumin were taken at study entry. Survival was compared by the Kaplan-Meier method and Cox regression analysis. One hundred seven patients died during the observation period; 66 died of cardiovascular diseases and 28 died of infectious diseases. Elevated serum relaxin concentrations (greater than median) predicted death in male but not in female patients with ESKD: All-cause death (men: relative risk, 2.63; 95% CI, 1.34 to 5.12;
P
=0.005; women: relative risk, 0.671; 95% CI, 0.33 to 1.35;
P
=0.262) and cardiovascular death (men: relative risk, 2.95; 95% CI, 1.20 to 7.21;
P
=0.018; women: relative risk, 0.639; 95% CI, 0.26 to 1.56;
P
=0.324).

Conclusions—

Relaxin is an independent risk factor predicting death in male patients with ESKD on chronic hemodialysis.
Microvascular Resistance Is Not Influenced by Epicardial Coronary Artery Stenosis Severity
Authors: Fearon William F. , Aarnoudse Wilbert , Pijls Nico H.J. , De Bruyne Bernard , Balsam Leora B. , Cooke David T. , Robbins Robert C. , Fitzgerald Peter J. , Yeung Alan C. , Yock Paul G.
Published: May 2004

Background—

The effect of epicardial artery stenosis on myocardial microvascular resistance remains controversial. Recruitable collateral flow, which may affect resistance, was not incorporated into previous measurements.

Methods and Results—

In an open-chest pig model, distal coronary pressure was measured with a pressure wire, and the apparent minimal microvascular resistance was calculated during peak hyperemia as pressure divided by flow, measured either with a flow probe around the coronary artery (R
micro app
) or with a novel thermodilution technique (apparent index of microcirculatory resistance [IMR
app
]). These apparent resistances were compared with the actual R
micro
and IMR after the coronary wedge pressure and collateral flow were incorporated into the calculation. Measurements were made at baseline (no stenosis) and after creation of moderate and severe epicardial artery stenoses. In 6 pigs, 189 measurements of R
micro
and IMR were made under the various epicardial artery conditions. Without consideration of collateral flow, R
micro app
(0.43±0.12 to 0.46±0.10 to 0.51±0.11 mm Hg/mL per minute) and IMR
app
(14±4 to 17±7 to 20±10 U) increased progressively and significantly with increasing epicardial artery stenosis (
P
<0.001 for both). With the incorporation of collateral flow, neither R
micro
nor IMR increased as a result of increasing epicardial artery stenosis.

Conclusions—

After collateral flow is taken into account, the minimum achievable microvascular resistance is not affected by increasing epicardial artery stenosis.
Hypoplastic Left Heart Syndrome With Intact or Highly Restrictive Atrial Septum
Authors: Vlahos Antonios P. , Lock James E. , McElhinney Doff B. , van der Velde Mary E.
Published: May 2004

Background—

Hypoplastic left heart syndrome (HLHS) with intact or very restrictive atrial septum is a highly lethal combination. We review our 13-year institutional experience treating this high-risk subgroup of patients with emergent catheter therapy.

Methods and Results—

Infants with HLHS requiring catheter septostomy within the first 2 days of life were compared with a matched control group with adequate interatrial communication. Preoperative, early postoperative, and medium-term survival were evaluated. Earlier experience was compared with recent results to assess the effect of changes in catheterization and surgical and intensive care unit management strategies over the study period. From 1990 to 2002, 33 newborns with HLHS (11% of newborns with HLHS managed during this period) underwent urgent/semiurgent catheterization to create or enlarge an interatrial communication before surgical palliation. Preoperative and early postoperative mortality were high (48%) compared with control HLHS patients, regardless of prenatal diagnosis and despite successful catheter-based atrial septostomy with clinical stabilization. Mortality trended down during the later part of the study period. Those who survived the neonatal period had late survival, pulmonary artery pressure, and resistance similar to those of control subjects.

Conclusions—

Neonatal mortality in the subgroup of HLHS patients with intact or highly restrictive atrial septum remains high despite successful urgent septostomy. Persistently poor outcomes for these patients have prompted efforts at our center to develop techniques for fetal intervention for this condition, in the hope that prenatal relief of left atrial and pulmonary venous hypertension may promote normal pulmonary vascular and parenchymal development and improve both short- and long-term outcomes.
Left Septal Atrial Flutter
Authors: Marrouche Nassir F. , Natale Andrea , Wazni Oussama M. , Cheng Jie , Yang Yanfei , Pollack Harvey , Verma Atul , Ursell Phillip , Scheinman Melvin M.
Published: May 2004

Background—

We describe the clinical and electrophysiological characteristics of a novel macroreentrant form of left atrial flutter circuit.

Methods and Results—

A total of 11 patients were included in the study. The mean tachycardia cycle length was 278±41 ms. Nine of the 11 patients were treated with antiarrhythmic drugs at the time of the study for concomitant atrial fibrillation. With the use of entrainment pacing and either the CARTO Biosense mapping system (9 patients) or conventional mapping (2 patients), the flutter circuit was found to rotate around the left septum primum with a critical isthmus located between the pulmonary veins posteriorly and/or mitral annulus anteriorly and the septum primum. In 5 patients, radiofrequency ablation was performed from the septum primum to the right inferior pulmonary vein (group 1), and in 6 patients, a lesion was made from the septum primum to the mitral annulus (group 2). After a follow-up of 13±6 months, 2 patients in group 1 and all patients in group 2 remained in sinus rhythm without recurrence.

Conclusions—

Slowing of electric conduction in the left atrial septum due to antiarrhythmic drugs and/or atrial myopathy seems to promote left septal atrial flutter. Radiofrequency ablation of this arrhythmia is usually effective and safe. A line of block between the septum primum and the mitral annulus proved to be effective for cure of tachycardia.
Mechano-Electrical Interaction Late After Fontan Operation
Authors: Wong Tom , Davlouros Periklis A. , Li Wei , Millington-Sanders Catherine , Francis Darrel P. , Gatzoulis Michael A.
Published: May 2004

Background—

The growing population with Fontan operation surviving into adulthood has significant morbidity and mortality rates from recurrent atrial tachyarrhythmias. We hypothesized that the structural characteristics and electrical behavior of atria may differ in these patients compared with those without arrhythmias.

Methods and Results—

We studied 33 consecutive patients (age, 25.4±9.5 years) with Fontan circulation, of whom 19 had a history of documented sustained atrial tachyarrhythmias. We analyzed their clinical and investigational data, including echocardiographic assessment of atrial dimensions and surface 12-lead ECG measurement of the P-wave duration and its dispersion between leads. Twenty age- and sex-matched healthy control subjects were also studied. First, patients who had the Fontan procedure overall had longer P-wave duration (144±33 versus 100±7 ms,
P
<0.001) and greater P-wave dispersion (74±33 versus 34±9 ms,
P
<0.001) than control subjects. Among the patients who had the Fontan procedure, those with atrial tachyarrhythmias had longer P-wave duration (159±28 versus 123±28 ms,
P
<0.001) and greater P-wave dispersion (91±30 versus 50±19 ms,
P
<0.001) than those without. Second, the patients with atrial tachyarrhythmias who had the Fontan procedure had larger right atrial dimension than those without arrhythmias (6.4±1.4 versus 5.0±1.0 cm,
P
=0.01). Third, both P-wave duration and dispersion were significantly correlated to right atrial dimension within the Fontan group (
r
=0.55,
P
=0.002, and
r
=0.56,
P
=0.002, respectively).

Conclusions—

Patients with atrial tachyarrhythmias late after Fontan operation have longer P-wave duration and P-wave dispersion and larger right atrial dimension than those without the arrhythmias; these abnormalities are interrelated. This observation represents an atrial mechano-electrical remodeling phenomenon in parallel to an increase in arrhythmia propensity in this vulnerable population and warrants further investigation.
AKT Participates in Endothelial Dysfunction in Hypertension
Authors: Iaccarino Guido , Ciccarelli Michele , Sorriento Daniela , Cipolletta Ersilia , Cerullo Vincenzo , Iovino Gianni Luigi , Paudice Alessandro , Elia Andrea , Santulli Gaetano , Campanile Alfonso , Arcucci Oreste , Pastore Lucio , Salvatore Francesco , Condorelli Gianluigi , Trimarco Bruno
Published: May 2004

Background—

In hypertension, reduced nitric oxide production and blunted endothelial vasorelaxation are observed. It was recently reported that AKT phosphorylates and activates endothelial nitric oxide synthase and that impaired kinase activity may be involved in endothelial dysfunction.

Methods and Results—

To identify the physiological role of the kinase in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), we used adenoviral vectors to transfer the human AKT1 gene selectively to the common carotid endothelium. In vitro, endothelial vasorelaxations to acetylcholine, isoproterenol, and insulin were blunted in control carotids from SHR compared with WKY rats, and human AKT1 overexpression corrected these responses. Similarly, blood flow assessed in vivo by Doppler ultrasound was reduced in SHR compared with WKY carotids and normalized after AKT1 gene transfer. In primary cultured endothelial cells, we evaluated AKT phosphorylation, activity, and compartmentalization and observed a mislocalization of the kinase in SHR.

Conclusions—

We conclude that AKT participates in the settings of endothelial dysfunction in SHR rats by impaired membrane localization. Our data suggest that AKT is involved in endothelium dysfunction in hypertension.
Soluble CD40 Ligand, Soluble P-Selectin, Interleukin-6, and Tissue Factor in Diabetes Mellitus
Authors: Lim Hoong Sern , Blann Andrew D. , Lip Gregory Y.H.
Published: May 2004

Background—

High levels of the soluble fragment of CD40 ligand (sCD40L) have previously been associated with adverse cardiovascular outcomes. CD40L–CD40 interaction has been linked to the pathogenesis of atherothrombotic complications in cardiovascular disease (CVD). We sought to determine whether a “package of care” of intensified multifactorial cardiovascular risk intervention could reduce indices of platelet activation, inflammation, and coagulation in diabetes and whether patients with overt CVD would derive similar benefit compared with those without.

Methods and Results—

We measured plasma sCD40L, soluble P-selectin (sP-sel, an index of platelet activation), interleukin-6 (IL-6, a proinflammatory cytokine), and tissue factor (TF, an initiator of coagulation) in 97 patients with diabetes mellitus (41 with and 56 without overt CVD) and 39 comparable healthy control subjects. Thirty-six patients with and 32 without overt CVD then participated in a package of care of cardiovascular risk intervention over a period of 1 year. Plasma levels of sCD40L (
P
<0.001), sP-sel (
P
<0.001), IL-6 (
P
=0.001), and TF (
P
<0.001) were higher in patients with diabetes than in control subjects, with TF levels highest in patients with overt CVD. Multifactorial intervention was associated with significant reductions in sCD40L in both patient groups (both
P
<0.001), but reductions in sP-sel and TF were seen only in patients without overt CVD. There was no significant change in IL-6 levels in both patient groups.

Conclusions—

Intensive multifactorial risk management can reduce high levels of sCD40L but can only partially correct abnormal platelet activation, inflammation, and coagulation in diabetes, particularly in patients with overt CVD.
The Microsomal Triglyceride Transfer Protein Gene-493T Variant Lowers Cholesterol But Increases the Risk of Coronary Heart Disease
Authors: Ledmyr Helena , McMahon Alex D. , Ehrenborg Ewa , Nielsen Lars B. , Neville Matt , Lithell Hans , MacFarlane Peter W. , Packard Christopher J. , Karpe Fredrik
Published: May 2004

Background—

The microsomal triglyceride transfer protein (MTP) transfers lipids into apolipoprotein B-containing lipoproteins for secretion from liver, intestine, and heart. The T-variant of a functional polymorphism in the MTP promoter, MTP-493G/T, has been associated with reduced low-density lipoprotein cholesterol concentrations. We hypothesize that this polymorphism impacts on coronary heart disease (CHD) risk.

Methods and Results—

The effect of the polymorphism was therefore tested in the West of Scotland Coronary Prevention Study biobank (580 cases and 1160 controls). MTP-493T carrier status was associated with significantly increased risk of CHD despite a small reduction in total cholesterol. Compared with the genotypic group with the lowest event rate (MTP-493GG, pravastatin treatment), the respective odds ratios (95% confidence interval) in the placebo group for CHD events were: GG, 1.23 (0.92 to 1.63); GT, 1.53 (1.12 to 2.08); and TT, 2.78 (1.53 to 5.05), suggestive of a gene-dose effect. The excess risk for CHD of the MTP-493T-variant was eliminated by pravastatin treatment. The Uppsala Longitudinal Study of Adult Men (ULSAM), which is a 20-year follow-up study of CHD, was used as an independent confirmatory database. These unexpected findings prompted the investigation of non-plasma lipid factors that could associate the MTP gene with CHD risk. In a limited number of subjects (n=18), heart muscle biopsies showed a MTP-493T genotype-specific depression of MTP mRNA expression.

Conclusion—

The MTP-493T variant confers an increased risk of CHD that is unrelated to plasma lipids and lipoproteins, but eliminated by pravastatin treatment. A direct effect of the MTP polymorphism on myocardial lipid metabolism and vulnerability upon ischemic damage cannot be excluded.
Complement 3 Is Involved in the Synthetic Phenotype and Exaggerated Growth of Vascular Smooth Muscle Cells From Spontaneously Hypertensive Rats
Authors: Lin Zhi-Hong , Fukuda Noboru , Jin Xue-Qing , Yao En-Hui , Ueno Takahiro , Endo Morito , Saito Satoshi , Matsumoto Koichi , Mugishima Hideo
Published: May 2004

Vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) show the synthetic phenotype and exaggerated growth in comparison with VSMCs from normotensive Wistar-Kyoto (WKY) rats. We investigated genes associated with the synthetic phenotype and exaggerated growth of VSMCs from SHR by microarray. Expression of 1300 transcripts was evaluated by microarray with total mRNA extracted from mid-layer aortic smooth muscle of 3-week-old SHR/Izumo and WKY/Izumo rats. mRNAs encoding sodium-dependent neurotransmitter transporter, epidermal growth factor precursor, EEF2, leptin receptor long-isoform b, clathrin assembly protein short form, and preprocomplement 3 (pre-pro-C3) were expressed only in aortic smooth muscle from SHR by microarray and by reverse-transcription polymerase chain reaction analysis. Pre-pro-C3 mRNA was detected only in cultured VSMCs from SHR. Exogenous C3 changed VSMCs to the synthetic phenotype. Antisense oligodeoxynucleotides (ODN) to C3 reduced the higher level of DNA synthesis in VSMCs from SHR. Antisense ODN to C3 increased expression of SM22α mRNA and decreased expression of osteopontin and matrix Gla mRNAs. It also decreased expression of growth factor mRNAs in VSMCs from SHR. In conclusion, we have shown that C3, independent of other complement molecules, has direct effects on the phenotype of VSMCs and stimulates growth of these cells. C3 is produced only by VSMCs from SHR. Therefore, C3 may be the gene underlying the synthetic phenotype and exaggerated growth of VSMCs from SHR. C3 may be a new target for the treatment of hypertension.
Proteomic and Metabolomic Analysis of Vascular Smooth Muscle Cells
Authors: Mayr Manuel , Siow Richard , Chung Yuen-Li , Mayr Ursula , Griffiths John R. , Xu Qingbo
Published: May 2004

Recent developments of proteomic and metabolomic techniques provide powerful tools for studying molecular mechanisms of cell function. Previously, we demonstrated that neointima formation was markedly increased in vein grafts of PKCδ-deficient mice compared with wild-type controls. To clarify the underlying mechanism, we performed a proteomic and metabolomic analysis of cultured vascular smooth muscle cells (SMCs) derived from PKCδ
+/+
and PKCδ
−/−
mice. Using 2-dimensional electrophoresis and mass spectrometry, we identified >30 protein species that were altered in PKCδ
−/−
SMCs, including enzymes related to glucose and lipid metabolism, glutathione recycling, chaperones, and cytoskeletal proteins. Interestingly, nuclear magnetic resonance spectroscopy confirmed marked changes in glucose metabolism in PKCδ
−/−
SMCs, which were associated with a significant increase in cellular glutathione levels resulting in resistance to cell death induced by oxidative stress. Furthermore, PKCδ
−/−
SMCs overexpressed RhoGDIα, an endogenous inhibitor of Rho signaling pathways. Inhibition of Rho signaling was associated with a loss of stress fiber formation and decreased expression of SMC differentiation markers. Thus, we performed the first combined proteomic and metabolomic study in vascular SMCs and demonstrate that PKCδ is crucial in regulating glucose and lipid metabolism, controlling the cellular redox state, and maintaining SMC differentiation.
Flow-Dependent Dilation Mediated by Endogenous Kinins Requires Angiotensin AT
2
Receptors
Authors: Bergaya Sonia , Hilgers Rob H.P. , Meneton Pierre , Dong You , Bloch-Faure May , Inagami Tadashi , Alhenc-Gelas François , Lévy Bernard I. , Boulanger Chantal M.
Published: May 2004

The vascular kallikrein-kinin system contributes to about one third of flow-dependent dilation in mice carotid arteries, by activating bradykinin B
2
receptors coupled to endothelial nitric oxide (NO) release. Because the bradykinin/NO pathway may mediate some of the effects of angiotensin II AT
2
receptors, we examined the possible contribution of AT
2
receptors to the kinin-dependent response to flow. Changes in outer diameter after increases in flow rate were evaluated in perfused arteries from wild-type animals (TK
+/+
) and in tissue kallikrein-deficient mice (TK
−/−
) in which the presence of AT
2
receptor expression was verified. Saralasin, a nonselective angiotensin II receptor antagonist, impaired significantly flow-induced dilation in TK
+/+
, whereas it had no effect in TK
−/−
mice. In both groups, blockade of AT
1
receptors with losartan or candesartan did not affect the response to flow. Inhibition of AT
2
receptors with PD123319 reduced significantly flow-induced dilation in TK
+/+
mice, but had no significant effect in TK
−/−
mice. Combining PD123319 with the bradykinin B
2
receptor antagonist HOE-140 had no additional effect to AT
2
receptor blockade alone in TK
+/+
arteries. Flow-dependent-dilation was also impaired in AT
2
receptor deficient mice (AT
2
−/−
) when compared with wild-type littermates. Furthermore, HOE-140 significantly reduced the response to flow in the AT
2
+/+
, but not in AT
2
−/−
mice. In conclusion, this study demonstrates that the presence of functional AT
2
receptors is necessary to observe the contribution of the vascular kinin-kallikrein system to flow-dependent dilation.
Stenting of Symptomatic M1 Stenosis of Middle Cerebral Artery
Authors: Jiang Wei-Jian , Wang Yong-Jun , Du Bin , Wang Su-Xiang , Wang Gui-Hong , Jin Min , Dai Jian-Ping
Published: May 2004

Objective—

To assess the safety and clinical efficacy of stenting for patients with symptomatic M1 stenosis of middle cerebral artery (MCA), and to assess the significance of classification based on location, morphology, and access of intracranial stenosis (LMA classification) in MCA stenting.

Methods—

Forty patients with 42 symptomatic M1 stenoses refractory to medical therapy were enrolled in this study. The lesions were situated at M1 trunk (n=13), M1 origin (n=12), and M1 bifurcation (n=17), respectively, which were classified into type N (nonbifurcation lesions, n=13) and type A (prebifurcation, n=11), B (postbifurcation, n=14), C (lesion across the nonstenotic ostium of its branch, n=1), D (across the stenotic ostium of its branch, n=2), F (combinative lesions of prebifurcation and its small branch ostium, n=1) locations, morphologically into type A (n=15), B (n=23) and C (n=4) lesions, and into type I (mild-to-moderate tortuosity and smooth access, n=17), II (severe tortuosity and/or irregular arterial wall, n=18), and III (excessively severe tortuosity, n=7) accesses.

Results—

The technical successful rate was 97.6% for total lesions and 100%, 100%, and 85.7% for types I, II, and III accesses, respectively. The total complication rate was 10%. The mortality was 2.5% (1/40 patients), and 0%, 0%, and 25% for types A, B, and C lesions, respectively. During the median 10 months follow-up, there was no recurrence of transient ischemic attack or stroke in 38 available patients. Among 8 stenting vessels of seven patients with six-month follow-up angiography, 7 showed good patency and one showed restenosis.

Conclusion—

Stenting appears to be an effective and feasible therapy for symptomatic M1 stenoses, but also appears to have the higher periprocedural complications, which need strict procedural and periprocedural management to reduce the mortality and morbidity. The LMA classification seems to be helpful to work out the individual therapy and predict the results of stenting. A further study is needed to confirm the benefits of stenting of MCA stenosis.
Autoantibodies Against
N
-Homocysteinylated Proteins in Humans
Authors: Undas Anetta , Perła Joanna , Łacinski Mariusz , Trzeciak Wiesław , Kaźmierski Radosław , Jakubowski Hieronim
Published: May 2004

Background and Purpose—

Homocysteine (Hcy)-thiolactone mediates protein N-homocysteinylation in humans. Protein N-linked Hcy comprises a major pool of Hcy in human blood, greater that the “total” Hcy pool. N-homocysteinylated proteins are structurally different, compared with native proteins, and are thus likely to be recognized as neoself antigens and induce an autoimmune response. This study was undertaken to provide evidence for anti–
N
ε-Hcy-Lys-protein antibody and to examine associations between the antibody level, Hcy, and stroke in humans.

Methods—

ELISA was used to quantify anti–
N
ε-Hcy-Lys-protein antibodies in human serum.

Results—

We found that autoantibodies that specifically recognize
N
ε-Hcy-Lys epitope on Hcy-containing proteins occur in humans. Serum levels of anti–
N
ε-Hcy-Lys-protein autoantibodies positively correlate with plasma total Hcy levels, but not with plasma cysteine or methionine levels. In a group of exclusively male patients with stroke, mean level of anti–
N
ε-Hcy-Lys-protein autoantibodies was ≈50% higher than in a group of healthy subjects.

Conclusion—

These findings support a hypothesis that
N
ε-Hcy-Lys-protein is a neoself antigen, which may contribute to immune activation, an important modulator of atherogenesis.
Delayed Decompressive Surgery Increases Apparent Diffusion Coefficient and Improves Peri-Infarct Perfusion in Rats With Space-Occupying Cerebral Infarction
Authors: Hofmeijer J. , Schepers J. , Veldhuis W.B. , Nicolay K. , Kappelle L.J. , Bär P.R. , van der Worp H.B.
Published: May 2004

Background and Purpose—

There is no conclusive experimental support that decompressive surgery in late stages of space-occupying cerebral infarction will improve outcome. We studied the effects of delayed decompressive surgery on the development of tissue damage, edema formation, and cerebral perfusion with different MRI techniques in a rat model of space-occupying cerebral infarction.

Methods—

Permanent middle cerebral artery (MCA) occlusion was performed in 6 Fisher 344 rats. Decompressive surgery was performed 17 hours after the occlusion. Each animal was assessed before surgery and 2 and 4 hours after surgery by means, of diffusion-weighted T2-weighted, and flow-sensitive alternating inversion recovery perfusion-weighted MRI. Ischemic damage was also evaluated in hematoxylin-eosin-stained brain sections.

Results—

Lesion volume as derived from apparent diffusion coefficient (ADC) maps decreased from 522±98 mm
3
before to 405±100 mm
3
(
P
=0.016) 4 hours after decompressive surgery, whereas lesion volume from T2 maps increased from 420±66 mm
3
before to 510±92 mm
3
(
P
=0.048) 4 hours after decompressive surgery. Midline shift decreased from 1.4±0.1 mm to 0.5±0.2 mm (
P
=0.001). Blood flow in the noninfarcted area of the ipsilateral hemisphere improved from 25±9 mL/min/100 g of tissue to 38±9 mL/min/100 g of tissue (
P
=0.035). Despite the pseudonormalization of ADC, irreversible damage was found in the entire MCA territory on histological evaluation.

Conclusions—

In rats with space-occupying cerebral infarction, delayed decompressive surgery leads to a decrease in lesion volume derived from ADC maps, which is probably because of an increase of extracellular water formation. There are no signs that this reflects rescue of ischemic tissue.
Phase-Contrast Magnetic Resonance Imaging Measurements of Cerebral Autoregulation With a Breath-Hold Challenge
Authors: de Boorder Michiel J. , Hendrikse Jeroen , van der Grond Jeroen
Published: May 2004

Background and Purpose—

Vasomotor reactivity (VMR) testing can identify patients with hemodynamically critical cerebrovascular disease. The use of VMR has been limited by the invasiveness of most of the available methods and of acetazolamide as VMR stimulus. In the present study, we evaluated a completely noninvasive VMR approach by combining quantitative phase-contrast magnetic resonance imaging (MRI) with a breath-hold challenge.

Methods—

Volume flow rates in the right and left internal carotid artery (ICA), basilar artery (BA), superior sagittal sinus, and sinus rectus were measured on 2-dimensional phase-contrast MR angiograms (MRAs) with a temporal resolution of 4.3 seconds. In 20 healthy control subjects, the VMR was assessed during 2 consecutive 30-second periods of breath-holding.

Results—

A flow increase on breath-holding of 66% was found for the left ICA (240±54 mL/min to 398±120 mL/min;
P
<0.01), 59% for the right ICA (253±98 mL/min to 402±159 mL/min;
P
<0.01), 71% for the BA (107±48 mL/min to 184±79 mL/min;
P
<0.01), 62% for the superior sagittal sinus (232±75 mL/min to 375±130 mL/min;
P
<0.01), and 65% for the sinus rectus (77±30 mL/min to 127±38 mL/min;
P
<0.01). The coefficient of variation for the total volume flow increase in the brain feeding arteries (ICAs and BA) between the first and the second breath-holds was 18%.

Conclusion—

The combination of MRA phase-contrast volume flow measurements and a breath-holding challenge allows for a fast, completely noninvasive, and reproducible assessment of VMR.
Lower Serum Triglyceride Level Is Associated With Increased Stroke Severity
Authors: Dziedzic Tomasz , Slowik Agnieszka , Gryz Elzbieta A. , Szczudlik Andrzej
Published: May 2004

Background and Purpose—

A previous study showed that low triglyceride concentration predicts higher mortality after stroke. The aim of our study was to determine whether serum triglyceride level is associated with stroke severity on admission.

Methods—

863 consecutive patients with acute ischemic stroke were included. Serum triglyceride level was measured within 36 hours after stroke onset. Stroke severity on admission was assessed using Scandinavian Stroke Scale (SSS). The patients were divided into 2 groups: those with severe stroke (SSS ≤25) and those with mild/moderate stroke (SSS >25).

Results—

Patients with severe stroke had significantly lower serum triglyceride level than patients with mild/moderate stroke (1.4±0.6 versus 1.7±1.3 mmol/L). After adjusting for age, sex, atrial fibrillation, diabetes mellitus, obesity, and ischemic heart disease, patients with triglyceride >2.3 mmol/L had lower risk of severe stroke than those with triglyceride ≤2.3 mmol/L (OR: 0.58; 95% CI: 0.35 to 0.95).

Conclusions—

Our results suggest that lower level of triglyceride is associated with the more severe stroke.