bluuebunny/crossref_metadata_2025 huggingface dataset:
Caffeine Alters A
2A
Adenosine Receptors and Their Function in Human Platelets
Authors: Varani Katia , Portaluppi Francesco , Merighi Stefania , Ongini Ennio , Belardinelli Luiz , Borea Pier Andrea
Published: June 2012

Background
—Caffeine acts mainly via blockade of adenosine receptors, which have been classified into A
1
, A
2A
, A
2B
, and A
3
subtypes. We determined whether repeated caffeine administration (750 mg/d for 1 week) upregulates the human platelet A
2A
adenosine receptor and is accompanied by sensitization of platelet responses (increase in cAMP accumulation and decrease in platelet aggregation) to selective stimulation of the A
2A
receptors.

Methods and Results
—Platelets were obtained from peripheral venous blood of 9 human volunteers at the end of 1 week of caffeine abstinence (control) and at 12 and 60 hours after the last dose of caffeine (withdrawal). The A
2A
receptor radioligand [
3
H]SCH 58261 {5-amino-7(phenylethyl)-2-(2-furyl)-pyrazolo[4,3-
e
]-1,2,4-triazolo[1,5-
c
]-pyrimidine} bound to a single affinity class of sites in platelet membranes from controls with a B
max
of 98±2 fmol/mg protein and a
K
D
of 1.29±0.05 nmol/L. At 12 and 60 hours after caffeine withdrawal, the radioligand bound with similar affinity (
K
D
=1.36±0.06 and 1.21±0.05 nmol/L, respectively), but the B
max
was increased (
P
<0.01) to 128±3 and 132±2 fmol/mg protein. The A
2A
receptor agonist 2-hexynyl-5′-
N
-ethylcarboxamidoadenosine (HE-NECA) increased cAMP accumulation (EC
50
=59±3 nmol/L) and inhibited (IC
50
=90±6 nmol/L) aggregation of control platelets. The EC
50
values for HE-NECA to increase cAMP accumulation of platelets were reduced (
P
<0.01) at 12 and 60 hours after caffeine withdrawal (31±3 and 21±2 nmol/L, respectively). The IC
50
values for HE-NECA to inhibit ADP-induced platelet aggregation were 50±5 and 30±2 nmol/L at 12 and 60 hours after caffeine withdrawal, respectively.

Conclusions
—Chronic caffeine intake leads to upregulation of A
2A
receptors and is accompanied by sensitization to the actions of the agonist HE-NECA.
Thrombogenic Factors and Recurrent Coronary Events
Authors: Moss Arthur J. , Goldstein Robert E. , Marder Victor J. , Sparks Charles E. , Oakes David , Greenberg Henry , Weiss Harvey J. , Zareba Wojciech , Brown Mary W. , Liang Chang-Seng , Lichstein Edgar , Little William C. , Gillespie John A. , Van Voorhees Lucy , Krone Ronald J. , Bodenheimer Monty M. , Hochman Judith , Dwyer Edward M. , Arora Rohit , Marcus Frank I. , Watelet Luc F. Miller , Case Robert B.
Published: June 2012

Background
—Thrombosis is a pivotal event in the pathogenesis of coronary disease. We hypothesized that the presence of blood factors that reflect enhanced thrombogenic activity would be associated with an increased risk of recurrent coronary events during long-term follow-up of patients who have recovered from myocardial infarction.

Methods and Results
—We prospectively enrolled 1045 patients 2 months after an index myocardial infarction. Baseline thrombogenic blood tests included 6 hemostatic variables (
d
-dimer, fibrinogen, factor VII, factor VIIa, von Willebrand factor, and plasminogen activator inhibitor-1), 7 lipid factors [cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, lipoprotein(a), apolipoprotein (apo)A-I, and apoB], and insulin. Patients were followed up for an average of 26 months, with the primary end point being coronary death or nonfatal myocardial infarction, whichever occurred first. The hemostatic, lipid, and insulin parameters were dichotomized into their top and the lower 3 risk quartiles and evaluated for entry into a Cox survivorship model. High levels of
d
-dimer (hazard ratio, 2.43; 95% CI, 1.49, 3.97) and apoB (hazard ratio, 1.82; 95% CI, 1.10, 3.00) and low levels of apoA-I (hazard ratio, 1.84; 95% CI, 1.10, 3.08) were independently associated with recurrent coronary events in the Cox model after adjustment for 6 relevant clinical covariates.

Conclusions
—Our findings indicate that a procoagulant state, as reflected in elevated levels of
d
-dimer, and disordered lipid transport, as indicated by low apoA-1 and high apoB levels, contribute independently to recurrent coronary events in postinfarction patients.
Cardiovascular Collapse Caused by Electrocardiographically Silent 60-Hz Intracardiac Leakage Current
Authors: Swerdlow Charles D. , Olson Walter H. , O’Connor Mark E. , Gallik Donna M. , Malkin Robert A. , Laks Michael
Published: June 2012

Background
—The national standard for safe 60-Hz intracardiac leakage current under a single-fault condition is 50 μA. This standard is intended to protect patients from alternating current (AC) at levels below the threshold for sensation, but the minimum unsafe level for AC in closed-chest humans is not known. To determine this value, we studied 40 patients at testing of implantable cardioverter-defibrillators using a programmable source of 60-Hz AC.

Methods and Results
—We applied AC for 5-second test periods in increasing strengths until ventricular fibrillation (VF) was induced or 1 mA was reached. Two current paths were tested: bipolar, between tip and ring electrodes of a right ventricular pacing catheter, and unipolar, from tip to a remote electrode. We observed a characteristic sequence of 3 responses as AC was increased: (1) intermittent ventricular capture with QRS morphology identical to pacing through the electrodes (minimum value, 20 μA); (2) continuous capture at cycle length 282±88 ms (minimum value, 32 μA); and (3) VF persisting after AC termination (minimum value, 49 μA). Continuous capture caused loss of pulsatile arterial pressure and cardiovascular collapse (mean arterial pressure, 32±8 mm Hg) for the duration of AC with no ECG evidence of AC stimulation. Thus, the clinical picture was that of hypotensive ventricular tachycardia (VT). The continuous-capture threshold was ≤50 μA in 9 patients (22%) for bipolar AC and in 5 (12%) for unipolar AC. All patients showed continuous capture over a wide range for both bipolar AC (68±18 to 216±238 μA) and unipolar AC (84±27 to 278±226 μA).

Conclusions
—Leakage current causes cardiovascular collapse at levels below the VF threshold. Stimulation by silent AC that is neither felt nor visible on the ECG presents as hypotensive VT. In patients with intracardiac electrodes, leakage current less than or equal to the present standard of 50 μA may cause VT or VF. The safety standard for leakage current lasting ≥5 seconds should be ≤20 μA. This standard should be based on the continuous-capture threshold.
Retroviral Gene Therapy in ApoE-Deficient Mice
Authors: Hasty Alyssa H. , Linton MacRae F. , Brandt Stephen J. , Babaev Vladimir R. , Gleaves Linda A. , Fazio Sergio
Published: June 2012

Background
—Apolipoprotein E (apoE) has long been known to play an important role in the clearance of plasma lipoproteins. More recently, a direct role for apoE in delaying atherogenesis has been proposed. Macrophage production of apoE in the artery wall has been demonstrated to provide protection against atherosclerotic lesion development independently from its role in lipoprotein clearance. However, whether macrophage apoE can affect lesion growth at all stages of atherogenesis remains to be established.

Methods and Results
—To evaluate the role of macrophage apoE in different stages of atherogenesis, as well as to establish a novel gene therapy approach to atherosclerotic vascular disease, we used an apoE-expressing retrovirus to transduce apoE-deficient (−/−) bone marrow for transplantation into apoE(−/−) recipient mice. Three weeks after bone marrow transplantation, apoE was expressed from arterial macrophages and was detectable in plasma associated with lipoproteins at 0.5% to 1% of normal levels but did not affect plasma cholesterol levels. We used 2 groups of recipient mice: younger mice with lesions consisting primarily of foam cells and older mice with more advanced lesions. When either the mouse or human apoE transgenes were expressed in mice from 5 to 13 weeks of age, there was a significant reduction in lesion area, whereas no effects were detected in mice that expressed apoE from 10 to 26 weeks of age.

Conclusions
—We demonstrate that arterial macrophage apoE secretion can delay atherogenesis if expressed during foam cell formation but is not beneficial during the later stages of atherogenesis. These data also provide evidence that apoE transgene expression from arterial macrophages may have therapeutic applications.
Efficient and Stable Transduction of Cardiomyocytes After Intramyocardial Injection or Intracoronary Perfusion With Recombinant Adeno-Associated Virus Vectors
Authors: Svensson Eric C. , Marshall Deborah J. , Woodard Karen , Lin Hua , Jiang Fang , Chu Lein , Leiden Jeffrey M.
Published: June 2012

Background
—The delivery of recombinant genes to cardiomyocytes holds promise for the treatment of a variety of cardiovascular diseases. Previous gene transfer approaches that used direct injection of plasmid DNA or replication-defective adenovirus vectors have been limited by low transduction frequencies and transient transgene expression due to immune responses, respectively. In this report, we have tested the feasibility of using intramyocardial injection or intracoronary infusions of recombinant adeno-associated virus (rAAV) vectors to program transgene expression in murine cardiomyocytes in vivo.

Methods and Results
—We constructed an rAAV containing the
LacZ
gene under the transcriptional control of the cytomegalovirus (CMV) promoter (AAV
CMV-LacZ
). We then injected 1×10
8
infectious units (IU) of this virus into the left ventricular myocardium of adult CD-1 mice. Control hearts were injected with the Ad
CMV-LacZ
adenovirus vector. Hearts harvested 2, 4, and 8 weeks after AAV
CMV-LacZ
injection demonstrated stable β-galactosidase (β-gal) expression in large numbers of cardiomyocytes without evidence of myocardial inflammation or myocyte necrosis. In contrast, the Ad
CMV-LacZ
-injected hearts displayed transient β-gal expression, which was undetectable by 4 weeks after injection. Explanted C57BL/6 mouse hearts were also perfused via the coronary arteries with 1.5×10
9
IU of AAV
CMV-LacZ
and assayed 2, 4, and 8 weeks later for β-gal expression. β-Gal expression was detected in <1% of cardiomyocytes at 2 weeks after perfusion but was detected in up to 50% of cardiomyocytes 4 to 8 weeks after perfusion.

Conclusions
—Direct intramyocardial injection or coronary artery perfusion with rAAV vectors can be used to program stable transgene expression in cardiomyocytes in vivo. rAAV appears to represent a useful vector for the delivery of therapeutic genes to the myocardium.
Repolarizing K
+
Currents
I
TO1
and
I
Ks
Are Larger in Right Than Left Canine Ventricular Midmyocardium
Authors: Volders Paul G. A. , Sipido Karin R. , Carmeliet Edward , Spätjens Roel L. H. M. G. , Wellens Hein J. J. , Vos Marc A.
Published: June 2012

Background
—The ventricular action potential exhibits regional heterogeneity in configuration and duration (APD). Across the left ventricular (LV) free wall, this is explained by differences in repolarizing K
+
currents. However, the ionic basis of electrical nonuniformity in the right ventricle (RV) versus the LV is poorly investigated. We examined transient outward (
I
TO1
), delayed (
I
Ks
and
I
Kr
), and inward rectifier K
+
currents (
I
K1
) in relation to action potential characteristics of RV and LV midmyocardial (M) cells of the same adult canine hearts.

Methods and Results
—Single RV and LV M cells were used for microelectrode recordings and whole-cell voltage clamping. Action potentials showed deeper notches, shorter APDs at 50% and 95% of repolarization, and less prolongation on slowing of the pacing rate in RV than LV.
I
TO1
density was significantly larger in RV than LV, whereas steady-state inactivation and rate of recovery were similar.
I
Ks
tail currents, measured at −25 mV and insensitive to almokalant (2 μmol/L), were considerably larger in RV than LV.
I
Kr
, measured as almokalant-sensitive tail currents at −50 mV, and
I
K1
were not different in the 2 ventricles.

Conclusions
—Differences in K
+
currents may well explain the interventricular heterogeneity of action potentials in M layers of the canine heart. These results contribute to a further phenotyping of the ventricular action potential under physiological conditions.
The Contribution of Activated Factor XIII to Fibrinolytic Resistance in Experimental Pulmonary Embolism
Authors: Reed Guy L. , Houng Aiilyan K.
Published: June 2012

Background
—The resistance of thrombi to fibrinolysis induced by plasminogen activators remains a major impediment to the successful treatment of thrombotic diseases. This study examines the contribution of activated factor XIII (factor XIIIa) to fibrinolytic resistance in experimental pulmonary embolism.

Methods and Results
—The fibrinolytic effects of specific inhibitors of factor XIIIa–mediated fibrin-fibrin cross-linking and α2-antiplasmin–fibrin cross-linking were measured in anesthetized ferrets with pulmonary emboli. Five experimental groups were treated with heparin (100 U/kg) and/or tissue plasminogen activator (TPA, 1 mg/kg) and the percent (mean±SD) lysis of emboli was determined: (1) control, normal factor XIIIa activity (14.1±4.8% lysis); (2) inhibited factor XIIIa activity (42.7±7.4%); (3) normal factor XIIIa activity+TPA (32.3±7.7%); (4) inhibited factor XIIIa activity+TPA (76.0±11.9%); and (5) inhibited α2-antiplasmin–fibrin cross-linking+TPA (54.7±3.9%). Inhibition of factor XIIIa activity increased endogenous lysis markedly (group 1 versus 2;
P
<0.0001), to a level comparable to that achieved with TPA (group 2 versus 3;
P
<0.05). Among groups receiving TPA, selective inhibition of factor XIII-mediated α2-antiplasmin–fibrin cross-linking enhanced lysis (group 3 versus 5;
P
<0.0005). Complete inhibition of factor XIIIa also amplified lysis (group 3 versus 4;
P
<0.0001) and had greater effects than inhibition of α2-antiplasmin cross-linking alone (group 4 versus 5;
P
<0.0005). No significant fibrinogen degradation occurred in any group.

Conclusions
—Factor XIIIa–mediated fibrin-fibrin and α2-antiplasmin–fibrin cross-linking both caused experimental pulmonary emboli to resist endogenous and TPA-induced fibrinolysis. This suggests that factor XIIIa may play a critical role in regulating fibrinolysis in human thrombosis.
Fate of the Stented Arterial Duct
Authors: Gibbs John L. , Uzun Orhan , Blackburn Michael E.C. , Wren Christopher , Hamilton J.R. Leslie , Watterson Kevin G.
Published: June 2012

Background
—The technical aspects of ductal stenting have been reported, but little is known of the fate of the duct after stent implantation.

Methods and Results
—Nineteen patients underwent stent implantation to maintain ductal patency. Eight had hypoplastic left heart (HLH) syndrome, 10 had pulmonary atresia, and 1 had tricuspid atresia. Median survival with HLH was 57 (12 to 907) days. Stent implantation was successful in all cases of HLH, but there were no long-term survivors. Two well-palliated infants died at transplantation. Median survival with duct-dependant pulmonary flow was 183 (0 to 1687) days, with 3 patients well at latest follow-up (56, 55, and 9 months, respectively). There were 2 operative deaths due to ductal spasm and 4 late deaths, 1 due to duct thrombosis, 1 due to chronic lung disease, and 2 of unknown cause. Stent implantation failed in 4 of the 11 cases. Assessment of endothelialization was possible in 13 cases; the stent was partially covered in 3 and fully endothelialized in all 10 cases assessed >8 weeks after implantation. In patients stented for inadequate pulmonary flow, ductal intimal hyperplasia occurred by 9 months in all 3 survivors but responded to repeated dilation.

Conclusions
—Ductal stenting cannot be recommended. In patients with HLH, it provides only short-term palliation even when combined with pulmonary artery banding. With duct-dependent pulmonary blood flow, the procedure carries high risk, and duration of palliation is poor. In patients with bilateral ducts and absent central pulmonary arteries, good palliation may be achieved, but repeated angioplasty is necessary to counteract intimal hyperplasia.
Prospective, Randomized Comparison of Effect of Long-Term Treatment With Metoprolol or Carvedilol on Symptoms, Exercise, Ejection Fraction, and Oxidative Stress in Heart Failure
Authors: Kukin Marrick L. , Kalman Jill , Charney Robert H. , Levy Daniel K. , Buchholz-Varley Cathleen , Ocampo Ofelia N. , Eng Calvin
Published: June 2012

Background
—With β-blocker use becoming more prevalent in treating chronic heart failure (CHF), the choice of drugs raises important theoretical and practical questions. Although the second-generation compound metoprolol is β
1
-selective, the third-generation compound carvedilol is β-nonselective, with ancillary pharmacological properties including α-blockade and antioxidant effects. A prospective comparison of these 2 agents can address the issue of optimal adrenergic blockade in selecting agents for therapy in CHF.

Methods and Results
—Sixty-seven patients with symptomatic stable heart failure were randomly assigned to receive either carvedilol or metoprolol in addition to standard therapy for CHF. Measured variables included symptoms, exercise, ejection fraction, and thiobarbituric acid–reactive substances (TBARS) as an indirect marker of free radical activity. Metoprolol and carvedilol were well tolerated, and both patient groups showed beneficial effects of β-blocker therapy in each of the measured parameters, with no between-group differences. Ejection fraction increased over 6 months from 18±6.3% to 23±8.7% (
P
<0.005) with metoprolol and from 19±8.5% to 25±9.9% (
P
<0.0005) with carvedilol (
P
=NS between groups). With metoprolol, TBARS values decreased from 4.7±0.9 nmol/mL at baseline to 4.2±1.5 nmol/mL at month 4 to 3.9±1.0 nmol/mL at month 6 (
P
<0.0001). With carvedilol, there was a parallel decline from 4.7±1.4 to 4.2±1.3 to 4.1±1.2 nmol/mL over the same time frame (
P
<0.025), with no between-group difference in these changes.

Conclusions
—Carvedilol and metoprolol showed parallel beneficial effects in the measured parameters over 6 months, with no relevant between-group differences in this heart failure population.
Activation of Cardiac Aldosterone Production in Rat Myocardial Infarction
Authors: Silvestre Jean-Sébastien , Heymes Christophe , Oubénaïssa Abdeslam , Robert Valérie , Aupetit-Faisant Brigitte , Carayon Alain , Swynghedauw Bernard , Delcayre Claude
Published: June 2012

Background
—This study analyzed the regulation and the role of the cardiac steroidogenic system in myocardial infarction (MI).

Methods and Results
—Seven days after MI, rats were randomized to untreated infarcted group or spironolactone- (20 and 80 mg · kg
−1
· d
−1
), losartan- (8 mg · kg
−1
· d
−1
), spironolactone plus losartan–, and L-NAME– (5 mg · kg
−1
· d
−1
) treated infarcted groups for 25 days. Sham-operated rats served as controls. In the noninfarcted myocardium of the left ventricle (LV), MI raised aldosterone synthase mRNA (the terminal enzyme of aldosterone synthesis) by 2.0-fold and the aldosterone level by 3.7-fold. Conversely, MI decreased 11β-hydroxylase mRNA (the terminal enzyme of corticosterone synthesis) by 2.4-fold and the corticosterone level by 1.9-fold. MI also induced a 1.9-fold increase in cardiac angiotensin II level. Such cardiac regulations were completely prevented by treatment of the infarcted heart with losartan. The MI-induced collagen deposition in noninfarcted LV myocardium was prevented by 1.6-fold by both low and high doses of spironolactone and by 2.5-fold by losartan. In addition, norepinephrine level was unchanged in infarcted heart but was attenuated by both losartan and spironolactone treatments.

Conclusions
—MI is associated with tissue-specific activation of myocardial aldosterone synthesis. This increase is mediated primarily by cardiac angiotensin II via AT
1
-subtype receptor and may be involved in post-MI ventricular fibrosis and in control of tissue norepinephrine concentration.
Stromelysin Promoter 5A/6A Polymorphism Is Associated With Acute Myocardial Infarction
Authors: Terashima Masahiro , Akita Hozuka , Kanazawa Kenji , Inoue Nobutaka , Yamada Shinichiro , Ito Keiichi , Matsuda Yasuaki , Takai Eiji , Iwai Chikao , Kurogane Hiroyuki , Yoshida Yutaka , Yokoyama Mitsuhiro
Published: June 2012

Background
—Rupture of the fibrous cap of an atherosclerotic plaque is a key event that predisposes to acute myocardial infarction (AMI). Matrix metalloproteinases (MMPs) may contribute to weakening of the cap, which favors rupture. Stromelysin, a member of MMP family, is identified extensively in human coronary atherosclerotic lesions. It can degrade most of the constituents of extracellular matrix as well as activating other MMPs, which suggests that it may play an important role in plaque rupture. Recently, a common variant (5A/6A) in the promoter of the stromelysin gene has been identified. The 5A/6A polymorphism could regulate the transcription of the stromelysin gene in an allele-specific manner.

Methods and Results
—To investigate the relation between the 5A/6A polymorphism in the promoter of the stromelysin gene and AMI, we conducted a case-control study of 330 AMI patients and 330 control subjects. The prevalence of the 5A/6A+5A/5A genotype was significantly more frequent in the patients with AMI than in control subjects (48.8% vs 32.7%,
P
<0.0001). In logistic regression models, the odds ratio of the 5A/6A+5A/5A was 2.25 (95% CI, 1.51 to 3.35). The association of 5A/6A polymorphism with AMI was statistically significant and independent of other risk factors.

Conclusions
—The 5A/6A polymorphism in the promoter of the stromelysin gene is a novel pathogenetic risk factor for AMI.
Double-Blind Placebo-Controlled Trial of Digoxin in Symptomatic Paroxysmal Atrial Fibrillation
Authors: Murgatroyd Francis D. , Gibson Sheila M. , Baiyan Xie , O’Nunain Sean , Poloniecki Jan D. , Ward David E. , Malik Marek , Camm A. John
Published: June 2012

Background
—Digoxin is commonly prescribed in symptomatic paroxysmal atrial fibrillation (AF) but has never been evaluated in this condition.

Methods and Results
—From a multicenter registry, 43 representative patients with frequent symptomatic AF episodes were recruited into a randomized, double-blind crossover comparison of digoxin (serum concentration, 1.29±0.35 nmol/L) and placebo. The study end point was the occurrence of 2 AF episodes (documented by patient-activated monitors), censored at 61 days. The median time to 2 episodes was 13.5 days on placebo and 18.7 days on digoxin (
P
<0.05). The relative risk (95% CI) of 2 episodes (placebo:digoxin) was 2.19 (1.07 to 4.50). A similar effect was seen on the median time to 1 episode: increased from 3.5 to 5.4 days (
P
<0.05), relative risk 1.69 (0.88 to 3.24). The mean±SD ventricular rates during AF recordings during placebo and digoxin treatment were 138±32 and 125±35 bpm, respectively (
P
<0.01). Twenty-four–hour ambulatory ECG recordings did not show significant differences in the frequency or duration of AF or in ventricular rate.

Conclusions
—Digoxin reduces the frequency of symptomatic AF episodes. However, the estimated effect is small and may be due to a reduction in the ventricular rate or irregularity rather than an antiarrhythmic action.
Remnant Lipoprotein Levels in Fasting Serum Predict Coronary Events in Patients With Coronary Artery Disease
Authors: Kugiyama Kiyotaka , Doi Hideki , Takazoe Keiji , Kawano Hiroaki , Soejima Hirofumi , Mizuno Yuji , Tsunoda Ryusuke , Sakamoto Tomohiro , Nakano Takamitsu , Nakajima Katsuyuki , Ogawa Hisao , Sugiyama Seigo , Yoshimura Michihiro , Yasue Hirofumi
Published: June 2012

Background
—Remnant lipoproteins are atherogenic, but assays of remnants have not been available in routine clinical laboratories because of the lack of practical and validated methods. A simple and reliable method for such an assay, using an immunochemical approach, has recently been developed. This study prospectively examined whether remnant lipoprotein levels in fasting serum, measured by our method, may have prognostic value in patients with coronary artery disease (CAD).

Methods and Results
—Remnant lipoprotein levels in fasting serum were measured in 135 patients with CAD by an immunoaffinity mixed gel containing anti-apolipoprotein (apo) A-1 and anti–apoB-100 monoclonal antibodies. Patients were followed up for ≤36 months until occurrence of 1 of the following clinical coronary events: recurrent or refractory angina pectoris requiring coronary revascularization, nonfatal myocardial infarction, or cardiac death. Kaplan-Meier analysis demonstrated a significantly higher probability of developing coronary events in patients with the highest tertile of remnant levels (>5.1 mg cholesterol/dL; 75th percentile of distribution of remnant levels) than in those with the lowest tertile of remnant levels (≤3.3 mg cholesterol/dL; 50th percentile of the distribution). Higher levels of remnants were a significant and independent predictor of developing coronary events in multivariate Cox hazard analysis including the following covariates: extent of coronary artery stenosis, age, sex, smoking, hypertension, diabetes mellitus, hypercholesterolemia, low HDL cholesterol, and hypertriglyceridemia.

Conclusions
—Higher levels of remnant lipoproteins in fasting serum predict future coronary events in patients with CAD independently of other risk factors. Thus, measurement of fasting remnant levels, assessed by the current immunoseparation method, may be helpful in assessment of CAD risk.
Glycosylphosphatidylinositol-Specific Phospholipase D Is Expressed by Macrophages in Human Atherosclerosis and Colocalizes With Oxidation Epitopes
Authors: O’Brien Kevin D. , Pineda Christine , Chiu Winnie S. , Bowen Rosario , Deeg Mark A.
Published: June 2012

Background
—Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) may play an important role in inflammation, because it can hydrolyze the GPI anchors of several inflammatory membrane proteins (eg, CD106, CD55, and CD59) and its hydrolytic products upregulate macrophage cytokine expression (eg, interleukin-1 and tumor necrosis factor-α). Because of its potential regulatory role in inflammatory reactions, we hypothesized that GPI-PLD might be expressed in atherosclerosis.

Methods and Results
—Immunohistochemistry using human GPI-PLD–specific rabbit polyclonal antiserum was performed on a total of 83 nonatherosclerotic and atherosclerotic human coronary arteries from 23 patients. Macrophages, smooth muscle cells, apoA-I, and oxidation epitopes also were identified immunohistochemically. Cell-associated GPI-PLD was detected in 95% of atherosclerotic segments, primarily on a subset of macrophages. Extracellular GPI-PLD was present in only 30% of atherosclerotic segments and localized to regions with extracellular apoA-I. In contrast, GPI-PLD was not detected in nonatherosclerotic segments. Expression of GPI-PLD mRNA by human macrophages was confirmed in vitro by reverse transcription/polymerase chain reaction. Further studies demonstrated that GPI-PLD–positive plaque macrophages contained oxidation epitopes, suggesting a link between oxidant stress and GPI-PLD expression. This possibility was supported by studies in which exposure of a macrophage cell line to H
2
O
2
led to a 50±3% increase in steady-state GPI-PLD mRNA levels.

Conclusions
—Collectively, these results suggest that oxidative processes may regulate GPI-PLD expression and suggest a role for GPI-PLD in inflammation and in the pathogenesis of atherosclerosis.
Lipoprotein Lipase Mutations, Plasma Lipids and Lipoproteins, and Risk of Ischemic Heart Disease
Authors: Wittrup Hans H. , Tybjærg-Hansen Anne , Nordestgaard Børge G.
Published: June 2012

Background
—We assessed in meta-analyses the effect of the Gly188Glu, Asp9Asn, Asn291Ser, and Ser447Ter substitutions in lipoprotein lipase in the heterozygous state on lipid metabolism and risk of ischemic heart disease (same order used below).

Methods and Results
—In 29 separate studies, 20 903 white subjects were screened for ≥1 of these substitutions; each meta-analysis included only some of these individuals. In population-based studies, heterozygote frequencies ranged from 0.04% to 0.2%, 2% to 4%, 1% to 7%, and 17% to 22% for the respective substitutions. Postheparin plasma lipoprotein lipase activity decreased 53% (95% CI, 31% to 75%) (only 1 study), 30% (22% to 37%), and 22% (8% to 35%) and was unchanged at 4% (−10% to 19%), respectively. Plasma triglycerides increased 78% (95% CI, 64% to 92%), 20% (9% to 33%), and 31% (20% to 43%) and decreased 8% (4% to 11%), respectively. HDL cholesterol decreased 0.25 mmol/L (0.18 to 0.32), 0.08 mmol/L (0.04 to 0.12), and 0.12 mmol/L (0.10 to 0.15) and increased 0.04 mmol/L (0.02 to 0.06), respectively. Odds ratios for ischemic heart disease were 4.9 (95% CI, 1.2 to 20) (only 1 study), 1.4 (0.8 to 2.4), 1.2 (0.9 to 1.5), and 0.8 (0.7 to 1.0), respectively. Subgroup analysis indicated that women with the Asn291Ser substitution may have an increased risk of ischemic heart disease.

Conclusions
—These meta-analyses suggest that compared with noncarriers, carriers of the Gly188Glu, Asp9Asn, and Asn291Ser substitutions have an atherogenic lipoprotein profile, whereas carriers of the Ser447Ter substitution have a protective lipoprotein profile. Accordingly, risk of ischemic heart disease in heterozygous carriers is increased for Gly188Glu carriers; at most, the increase is borderline for Asp9Asn and Asn291Ser carriers; and risk is possibly decreased for Ser447Ter carriers.
Heightened Tissue Factor Associated With Tissue Factor Pathway Inhibitor and Prognosis in Patients With Unstable Angina
Authors: Soejima Hirofumi , Ogawa Hisao , Yasue Hirofumi , Kaikita Koichi , Nishiyama Koichi , Misumi Kenji , Takazoe Keiji , Miyao Yuji , Yoshimura Michihiro , Kugiyama Kiyotaka , Nakamura Shin , Tsuji Ichiro , Kumeda Kousuke
Published: June 2012

Background
—This study was designed to evaluate the plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with unstable angina and investigate whether there is a relationship between these levels and unfavorable outcome.

Methods and Results
—The plasma TF and free TFPI antigen levels were determined in plasma samples taken from 51 patients with unstable angina, 56 with stable exertional angina, and 55 with chest pain syndrome. The plasma TF and free TFPI antigen levels were higher in the unstable angina group than in the stable exertional angina and chest pain syndrome group. There was a good correlation between TF and TFPI. We established borderline as maximum level in the patients with chest pain syndrome. Seven patients (of the 22 in the high TF group) required revascularization to control their unstable angina during in-hospital stay. On the other hand, only 1 of the 29 patients in the low TF group required myocardial revascularization. Four patients of the 14 patients in the high free TFPI group required myocardial revascularization during in-hospital stay, and 4 of the 37 patients in the low free TFPI group required myocardial revascularization. We compared the TF and free TFPI levels between the cardiac event (+) group and cardiac event (−) group. TF levels were significantly higher in the cardiac event (+) group than in the cardiac event (−) group.

Conclusions
—We have demonstrated that not only the plasma TF levels but also the plasma-free TFPI levels are elevated in patients with unstable angina. Patients with unstable angina and heightened TF and free TFPI are at increased risk for unfavorable outcomes. The heightened TF level was a more important predictor in patients with unstable angina.
Ganglionic Mechanisms Contribute to Diminished Vagal Control in Heart Failure
Authors: Bibevski Steve , Dunlap Mark E.
Published: June 2012

Background
—Previous work has shown that spontaneous and stimulated vagal activity is diminished in heart failure (HF) despite upregulation of functional postsynaptic cholinergic mechanisms. We therefore examined function of the postganglionic neuron in the paced canine model of HF as a possible site for diminished control.

Methods and Results
—We measured sinus cycle length changes in response to electrical stimulation of preganglionic and postganglionic parasympathetic neurons innervating the sinoatrial node in control and HF dogs (both, n=8). Cervical vagus stimulation (preganglionic) demonstrated attenuated responses in the HF group at all levels of stimulation (
P
<0.05). Stimulation of the right atrial fat pad, containing both postganglionic nerves and terminals of preganglionic neurons, showed no such difference between control and HF (200±25 versus 192±18 ms). To ensure that preganglionic input and different levels of baseline sympathetic activity did not contribute to the group difference, similar stimulations were done in the presence of ganglionic and β-adrenergic blockade. Under these conditions, postganglionic stimulation showed smaller changes in sinus cycle length, but the HF group response remained significantly higher than in controls (76±10 versus 20±2 ms;
P
<0.01), indicating that the difference was independent of preganglionic input and sympathetic activity.

Conclusions
—A component of attenuated parasympathetic control in HF is located within the peripheral efferent limb. This defect is located within the parasympathetic ganglion. Future work should be focused on determining mechanisms of attenuated ganglionic transmission so that means targeted at restoring vagal activity can be developed.
Membrane Type 1 Matrix Metalloproteinase Expression in Human Atherosclerotic Plaques
Authors: Rajavashisth Tripathi B. , Xu Xiao-Ping , Jovinge Stefan , Meisel Simcha , Xu Xiao-Ou , Chai Ning-Ning , Fishbein Michael C. , Kaul Sanjay , Cercek Bojan , Sharifi Behrooz , Shah Prediman K.
Published: June 2012

Background
—Matrix metalloproteinases (MMPs) are expressed in atherosclerotic plaques, where in their active form, they may contribute to vascular remodeling and plaque disruption. In this study, we tested the hypothesis that membrane type 1 MMP (MT1-MMP), a novel transmembrane MMP that activates pro-MMP-2 (gelatinase A), is expressed in human atherosclerotic plaques and that its expression is regulated by proinflammatory molecules.

Methods and Results
—MT1-MMP expression was examined in normal and atherosclerotic human arteries by immunocytochemistry with specific antibodies. MT1-MMP expression in human saphenous vein–derived smooth muscle cells (SMCs) maintained in tissue culture was determined under basal conditions and in response to proinflammatory molecules (interleukin [IL]-1α, tumor necrosis factor [TNF]-α, and oxidized LDL [ox-LDL]) by use of Northern blot and ribonuclease protection assays for mRNA, Western blot and immunoprecipitation for protein, and gelatin zymography for catalytic activity. Medial SMCs of normal vessel wall expressed MT1-MMP. In atherosclerotic arteries, MT1-MMP expression was noted within the complex atheroma colocalizing with SMCs and macrophages (Mφ). Cultured SMCs constitutively expressed MT1-MMP mRNA and protein, which increased 2- to 4-fold over control in a time-dependent manner within 4 to 8 hours of exposure to IL-1α, TNF-α, and ox-LDL (thiobarbituric acid–reactive substances, 13.4 nmol/mg LDL protein), whereas native LDL had no effect. Flow cytometry revealed MT1-MMP expression by human monocyte-derived Mφ, which increased 3.8-fold over baseline within 6 hours after exposure to 10 ng/mL TNF-α.

Conclusions
—This study demonstrates that MT1-MMP, an activator of pro-MMP-2, is expressed by SMCs and Mφ in human atherosclerotic plaques. Furthermore, proinflammatory molecules upregulate MT1-MMP expression in vascular SMCs and Mφ. Thus, activation of SMCs and Mφ by proinflammatory molecules may influence extracellular matrix remodeling in atherosclerosis by regulating MT1-MMP expression.
Improved Coronary Artery Definition With T2-Weighted, Free-Breathing, Three-Dimensional Coronary MRA
Authors: Botnar René M. , Stuber Matthias , Danias Peter G. , Kissinger Kraig V. , Manning Warren J.
Published: June 2012

Background
—Three-dimensional (3D) navigator-gated and prospectively corrected free-breathing coronary magnetic resonance angiography (MRA) allows for submillimeter image resolution but suffers from poor contrast between coronary blood and myocardium. Data collected over >100 ms/heart beat are also susceptible to bulk cardiac and respiratory motion. To address these problems, we examined the effect of a T2 preparation prepulse (T2prep) for myocardial suppression and a shortened acquisition window on coronary definition.

Methods and Results
—Eight healthy adult subjects and 5 patients with confirmed coronary artery disease (CAD) underwent free-breathing 3D MRA with and without T2prep and with 120- and 60-ms data-acquisition windows. The T2prep resulted in a 123% (
P
<0.001) increase in contrast-to-noise ratio (CNR). Coronary edge definition was improved by 33% (
P
<0.001). Acquisition window shortening from 120 to 60 ms resulted in better vessel definition (11%;
P
<0.001). Among patients with CAD, there was a good correspondence with disease.

Conclusions
—Free-breathing, T2prep, 3D coronary MRA with a shorter acquisition window resulted in improved CNR and better coronary artery definition, allowing the assessment of coronary disease. This approach offers the potential for free-breathing, noninvasive assessment of the major coronary arteries.
Health-Related Quality of Life After Angioplasty and Stent Placement in Patients With Iliac Artery Occlusive Disease
Authors: Bosch Johanna L. , van der Graaf Yolanda , Hunink Maria G. M.
Published: June 2012

Backround
—To assess the quality of life in patients with iliac artery occlusive disease, we compared primary stent placement versus primary angioplasty followed by selective stent placement in a multicenter randomized controlled trial.

Methods and Results
—Quality-of-life assessments were completed by 254 patients in a telephone interview. Assessment measures consisted of the RAND 36-Item Health Survey 1.0, time tradeoff, standard gamble, rating scale, health utilities index, and EuroQol-5D. The interviews were performed before treatment and after 1, 3, 12, and 24 months. When the 2 treatments were compared, no significant difference was observed (
P
>0.05). All measurements showed a significant improvement in the quality of life after treatment (
P
<0.05). The RAND 36-Item Health Survey measures physical functioning, role limitations caused by physical problems, and bodily pain and the EuroQol-5D were the most sensitive to the impact of revascularization.

Conclusions
—Health-related quality of life improves equally after primary stent placement and primary angioplasty with selective stent placement in the treatment of intermittent claudication caused by iliac artery occlusive disease.
QT Interval Is Linked to 2 Long-QT Syndrome Loci in Normal Subjects
Authors: Busjahn Andreas , Knoblauch Hans , Faulhaber Hans-Dieter , Boeckel Thomas , Rosenthal Magda , Uhlmann Regina , Hoehe Margret , Schuster Herbert , Luft Friedrich C.
Published: June 2012

Background
—The rate-corrected QT interval (QTc) is heritable, and the discovery of quantitative trait loci that influence the QTc would be an important step in identifying the genes responsible for life-threatening arrhythmias in the general population. We studied 66 pairs of unselected normal dizygotic (DZ) twin subjects and their parents in a sib-pair analysis. We tested for linkage of gene loci harboring genes known to cause the long-QT syndrome (LQT) to the quantitative trait QTc.

Methods and Results
—We found genetic variance on QRS duration, QRS axis, T-wave axis, and QTc. Women had a longer QTc than men. Microsatellite markers were tested in the vicinity of the gene loci for the 5 known LQT genes. We found significant linkage of QTc with the loci for LQT1 on chromosome 11 and LQT4 on chromosome 4 but not to LQT2, LQT3, or LQT5. We also found linkage of the QRS axis with LQT2 and LQT3.

Conclusions
—We suggest that these quantitative trait loci may represent the presence of variations in LQT genes that could be important to the risk for rhythm disturbances in the general population.
Impaired Collateral Vessel Development Associated With Reduced Expression of Vascular Endothelial Growth Factor in ApoE
−/−
Mice
Authors: Couffinhal Thierry , Silver Marcy , Kearney Marianne , Sullivan Alison , Witzenbichler Bernhard , Magner Meredith , Annex Brian , Peters Kevin , Isner Jeffrey M.
Published: June 2012

Background
—The impact of disordered lipid metabolism on collateral vessel development was studied in apolipoprotein (apo)E
−/−
mice with unilateral hindlimb ischemia.

Methods and Results
—Hindlimb blood flow and capillary density were markedly reduced in apoE
−/−
mice versus C57 controls. This was associated with reduced expression of vascular endothelial growth factor (VEGF) in the ischemic limbs of apoE
−/−
mice. Cell-specific immunostaining localized VEGF protein expression to skeletal myocytes and infiltrating T cells in the ischemic limbs of C57 mice; in contrast, T-cell infiltrates in ischemic limbs of apoE
−/−
mice were severely reduced. The critical contribution of T cells to VEGF expression and collateral vessel growth was reinforced by the finding of accelerated limb necrosis in athymic nude mice with operatively induced hindlimb ischemia. Adenoviral VEGF gene transfer to apoE
−/−
mice resulted in marked augmentation of hindlimb blood flow and capillary density.

Conclusions
—These findings thus underscore the extent to which hyperlipidemia adversely affects native collateral development but does not preclude augmented collateral vessel growth in response to exogenous cytokines. Moreover, results obtained in the apoE
−/−
and athymic nude mice imply a critical role for infiltrating T cells as a source of VEGF in neovascularization of ischemic tissues.
Reporting Risks and Benefits of Therapy by Use of the Concepts of Unqualified Success and Unmitigated Failure
Authors: Mancini G. B. John , Schulzer Michael
Published: June 2012

Background
—The NNT (number needed to treat) and NNH (number needed to harm) are useful in conveying the results of clinical trials because they emphasize the effort that must be expended to accomplish a single, tangible outcome. But NNT conveys the effort required to achieve a positive outcome without distinguishing between the presence or absence of treatment-related adverse events. Similarly, NNH conveys harm without accounting for the achievement or lack of achievement of the benefit of therapy. Consequently, a mathematical model was developed to extend the NNT and NNH to represent the effort required to achieve “unqualified success” (NNT
US
, treatment success without treatment-induced side effects) and “unmitigated failure” (NNH
UF
, lack of treatment success with treatment-induced side effects).

Methods and Results
—NNT
US
was calculated by adjusting the absolute risk reduction to allow for the probability of not incurring a treatment-related adverse event. NNH
UF
was similarly calculated by adjusting the absolute risk of incurring a treatment-related adverse event by the probability of not incurring any treatment-related benefit. The impact of conveying clinical trial data by the use of NNT, NNT
US
, NNH, and NNH
UF
is illustrated by means of 11 highly cited trials identified systematically from the cardiovascular literature. The treatment effort measured by the NNT
US
and the NNH
UF
was consistently higher than that given by the traditional NNT and NNH. These increments ranged from 1% to several hundred percent.

Conclusions
—The NNT
US
and the NNH
UF
represent the treatment effort required on average to achieve 1 unqualified success and 1 unmitigated failure. NNT
US
and NNH
UF
balance benefit and harm in an objective way and are relevant for making service delivery decisions.
Regulation of CCAAT/Enhancer Binding Protein, Interleukin-6, Interleukin-6 Receptor, and gp130 Expression During Myocardial Ischemia/Reperfusion
Authors: Chandrasekar Bysani , Mitchell Donald H. , Colston James T. , Freeman Gregory L.
Published: June 2012

Background
—Interleukin (IL)-6 is elevated in myocardium after ischemia and reperfusion. The IL-6 promoter/enhancer region contains response elements for nuclear factor-κB, AP-1, and CCAAT/enhancer binding protein (C/EBP). Expression and regulation of C/EBP in rat myocardium after ischemia and reperfusion has not been defined, nor has the behavior of the specific IL-6 receptor (IL-6R) or the signal transducer gp130.

Methods and Results
—C/EBP DNA binding activity was not detected in shams or in previously ischemic tissue at 15 minutes of reperfusion; it was detected at 30 minutes of reperfusion, increased at 1 hour of reperfusion, and declined by 6 hours of reperfusion. A supershift was observed with anti–C/EBP-β but not with anti-α or anti-δ antibodies. mRNA and protein levels of IL-6 and gp130 were detected at low levels in controls, increased at 1 hour of reperfusion, and remained high until 6 hours of reperfusion. IL-6R mRNA and protein were not detected in controls, but its mRNA was induced at 1 hour of reperfusion and its protein at 2 hours of reperfusion. Although effects of reperfusion were rapid, in ischemic tissue not reperfused, low levels of C/EBP were detected at 4 hours, and at 24 hours the levels were slightly elevated. Significant upregulation in IL-6, IL-6R, and gp130 occurred only at 24 hours of sustained ischemia.

Conclusions
—Reperfusion after a brief period of ischemia caused induction of myocardial C/EBP (β-subunit). The rapid and sustained production of IL-6 with concomitant expression of IL-6 receptor and gp130 suggest that these factors may participate in a local inflammatory cascade after myocardial ischemia and reperfusion.
α-Adrenergic Blockade Improves Recovery of Myocardial Perfusion and Function After Coronary Stenting in Patients With Acute Myocardial Infarction
Authors: Gregorini Luisa , Marco Jean , Kozàkovà Michaela , Palombo Carlo , Anguissola Gian Battista , Marco Isabelle , Bernies Monique , Cassagneau Bernard , Distante Alessandro , Bossi Irene M. , Fajadet Jean , Heusch Gerd
Published: June 2012

Background
—AMI reperfusion by thrombolysis does not improve TIMI flow and LV function. The role of infarct-related artery (IRA) stenosis and superimposed changes in coronary vasomotor tone in maintaining LV dysfunction must be elucidated.

Methods and Results
—Forty patients underwent diagnostic angiography 24 hours after thrombolysis. Seventy-two hours after thrombolysis, the culprit lesion was dilated with coronary stenting. During angioplasty, LV function was monitored by transesophageal echocardiography. Percent regional systolic thickening was quantitatively assessed before PTCA, soon after stenting, 15 minutes after stenting, and after phentolamine 12 μg/kg IC (n=10), the α
1
-blocker urapidil 600 μg/kg IV (n=10), or saline (n=10). Ten patients pretreated with β-blockers received urapidil 10 mg IC. Coronary stenting significantly improved thickening in IRA-dependent and in non–IRA-dependent myocardium (from 27±15% to 38±16% and from 40±15% to 45±15%, respectively). Simultaneously, TIMI frame count decreased from 39±11 and 40±11 in the IRA and non-IRA, respectively, to 23±10 and 25±7 (
P
<0.05). Fifteen minutes after stenting, thickening worsened in both IRA- and non–IRA-dependent myocardium (to 19±14% and 28±14%,
P
<0.05), and TIMI frame count returned, in both the IRA and non-IRA, to the values obtained before stenting. Phentolamine and urapidil increased thickening to 36±17% and 41±14% in IRA and to 48±11% and 49±17% in non-IRA myocardium respectively, and TIMI frame count decreased to 16±6 and to 17±5, respectively. Changes were attenuated with β-blocker pretreatment.

Conclusions
—Our finding that α-adrenergic blockade attenuates vasoconstriction and postischemic LV dysfunction supports the hypothesis of an important role of neural mechanisms in this phenomenon.