bluuebunny/crossref_metadata_2025 huggingface dataset:
Compensatory upregulation of the adenosine system following phenylephrine-induced hypertrophy in cultured rat ventricular myocytes
Authors: Pang Theresa , Gan Xiaohong Tracey , Freeman David J. , Cook Michael A. , Karmazyn Morris
Published: December 2009

Adenosine has been shown to exert direct antihypertrophic effects on the heart, and plasma adenosine levels have been shown to be elevated in patients with heart failure. It has therefore been proposed that endogenously synthesized adenosine may function as a cardiac antihypertrophic factor. The present study was aimed to determine whether the adenosine system is altered in a potential adaptive manner following phenylephrine-induced hypertrophy in cultured neonatal rat ventricular myocytes. Phenylephrine produced significant hypertrophy as determined by cell size and atrial natriuretic peptide gene expression, which was accompanied by significantly increased gene and protein expression of adenosine A1, A2a, and A3 receptors. These effects and the hypertrophic response were prevented by the α1-adrenoceptor antagonist prazosin as well as pharmacological agonists for all adenosine receptor subtypes. The upregulation of adenosine receptors by phenylephrine was also abrogated by adenosine 5′-(α,β-methylene)diphosphate, an inhibitor of ectosolic 5′-nucleotidase. Moreover, phenylephrine significantly increased production of adenosine from myocytes in the presence of a nucleoside transport and adenosine deaminase inhibitor, the combination of which abrogated the hypertrophic effect of phenylephrine. The latter effect was reversed by adenosine receptor antagonists. Phenylephrine also produced a significant upregulation in expression levels of equilibrative nucleoside transporter 1 although expression levels of equilibrative nucleoside transporter 2 were unaffected. Taken together, our results suggest an adaptive upregulation of the adenosine system to phenylephrine-induced cardiomyocyte hypertrophy that serves to limit the hypertrophic effect of α1-adrenoceptor activation.
Evidence for enhanced M3 muscarinic receptor function and sensitivity to atrial arrhythmia in the RGS2-deficient mouse
Authors: Tuomi Jari M. , Chidiac Peter , Jones Douglas L.
Published: December 2009

Atrial fibrillation (AF) is the most common arrhythmia seen in general practice. Muscarinic ACh receptors (M2R, M3R) are involved in vagally induced AF. M2R and M3R activate the heterotrimeric G proteins, Gi and Gq, respectively, by promoting GTP binding, and these in turn activate distinct K+ channels. Signaling is terminated by GTP hydrolysis, a process accelerated by regulator of G protein signaling (RGS) proteins. RGS2 is selective for Gq and thus may regulate atrial M3R signaling. We hypothesized that knockout of RGS2 (RGS2−/−) would render the atria more susceptible to electrically induced AF. One-month-old male RGS2−/− and C57BL/6 wild-type (WT) mice were instrumented for intracardiac electrophysiology. Atrial effective refractory periods (AERPs) were also determined in the absence and presence of carbachol, atropine, and/or the selective M3R antagonist darifenacin. Susceptibility to electrically induced AF used burst pacing and programmed electrical stimulation with one extrastimulus. Real-time RT-PCR measured atrial and ventricular content of RGS2, RGS4, M2R, M3R, and M4R mRNA. AERP was lower in RGS2−/− compared with WT mice in both the high right atrium (HRA) (30 ± 1 vs. 34 ± 1 ms, P < 0.05) and mid right atrium (MRA) (21 ± 1 vs. 24 ± 1 ms, P < 0.05). Darifenacin eliminated this difference (HRA: 37 ± 2 vs. 39 ± 2 ms, and MRA: 30 ± 2 vs. 30 ± 1, P > 0.4). RGS2−/− were more susceptible than WT mice to atrial tachycardia/fibrillation (AT/F) induction (11/22 vs. 1/25, respectively, P < 0.05). Muscarinic receptor expression did not differ between strains, whereas M2R expression was 70-fold higher than M3R ( P < 0.01). These results suggest that RGS2 is an important cholinergic regulator in the atrium and that RGS2−/− mice have enhanced susceptibility to AT/F via enhanced M3 muscarinic receptor activity.
Reduced expression of Cx43 attenuates ventricular remodeling after myocardial infarction via impaired TGF-β signaling
Authors: Zhang Yan , Wang Hongtao , Kovacs Attila , Kanter Evelyn M. , Yamada Kathryn A.
Published: December 2009

In addition to mediating cell-to-cell electrical coupling, gap junctions are important in tissue repair, wound healing, and scar formation. The expression and distribution of connexin43 (Cx43), the major gap junction protein expressed in the heart, are altered substantially after myocardial infarction (MI); however, the effects of Cx43 remodeling on wound healing and the attendant ventricular dysfunction are incompletely understood. Cx43-deficient and wild-type mice were subjected to proximal ligation of the anterior descending coronary artery and followed for 6 days or 4 wk to test the hypothesis that reduced expression of Cx43 influences wound healing, fibrosis, and ventricular remodeling after MI. We quantified the progression of infarct healing by measuring neutrophil expression, collagen content, and myofibroblast expression. We found significantly reduced transformation of fibroblasts to myofibroblasts at 6 days and significantly reduced collagen deposition both in the infarct at 6 days and at 4 wk in the noninfarcted region of Cx43-deficient mice. As expected, transforming growth factor (TGF)-β, a profibrotic cytokine, was dramatically upregulated in MI hearts, but its phosphorylated comediator (pSmad) was significantly downregulated in the nuclei of Cx43-deficient hearts post-MI, suggesting that downstream signaling of TGF-β is diminished substantially in Cx43-deficient hearts. This diminution in profibrotic TGF-β signaling resulted in the attenuation of adverse structural remodeling as assessed by echocardiography. These findings suggest that efforts to enhance the expression of Cx43 to maintain intercellular coupling or reduce susceptibility to arrhythmias should be met with caution until the role of Cx43 in infarct healing is fully understood.
Elevation of myostatin and FOXOs in prolonged muscular impairment induced by eccentric contractions in rat medial gastrocnemius muscle
Authors: Ochi Eisuke , Hirose Tatsuro , Hiranuma Kenji , Min Seok-Ki , Ishii Naokata , Nakazato Koichi
Published: December 2009

This study aimed to investigate torque deficit and activation of protein synthesis and/or protein degradation signaling pathways during the early and recovery phase after high- and low-velocity eccentric contractions (ECs). Male Wistar rats ( n = 36) were randomly divided into fast angular velocity ECs group (FAST; 180°/s; n = 12), slow ECs group (SLOW; 30°/s; n = 12), and control group (control; n = 12). ECs comprised four sets of five forced dorsiflexions combined with electrical stimulation of the plantar flexors. Isometric tetanic torque was measured before and after ECs. Tissue contents of Akt(P) (P, phosphorylated), mammalian target of rapamycin (mTOR)(P), 70-kDa ribosomal protein S6 kinase (P70S6k), P70S6k(P), forkhead transcription factor 1 of the O class (FOXO1), FOXO1(P), FOXO3, FOXO3(P), myostatin, and activin receptor type IIB (ActRIIB) were measured. The isometric tetanic torque after ECs was significantly lower in FAST than in SLOW ( days 1, 3, and 5, P < 0.05; day 2, P < 0.01). The ratio of P70S6k(P) against total P70S6k on days 2 and 7 was significantly higher in SLOW than in the control. The ratio of FOXO1 against total FOXO1, the ratio of FOXO3a against total FOXO3a, and myostatin on days 2 and 7 were significantly higher in FAST than in the control, while that of ActRIIB on day 7 was significantly lower in SLOW than in the other two groups. These results suggest that EC intensity plays a key role in impairment of muscular function and activation of protein synthesis and/or protein degradation signaling pathways.
Effects of excess corticosterone on LKB1 and AMPK signaling in rat skeletal muscle
Authors: Nakken G. Nathan , Jacobs Daniel L. , Thomson David M. , Fillmore Natasha , Winder William W.
Published: December 2009

Cushing's syndrome is characterized by marked central obesity and insulin insensitivity, effects opposite those seen with chronic AMP-activated protein kinase (AMPK) activation. This study was designed to determine whether chronic exposure to excess glucocorticoids influences LKB1/AMPK signaling in skeletal muscle. Corticosterone pellets were implanted subcutaneously in rats (hypercorticosteronemia, Hypercort) for 2 wk. Controls were sham operated and fed ad libitum or were sham operated and food restricted (pair-weighted group, Pair) to produce body weights similar to Hypercort rats. At the end of the 2-wk treatment period, rats were anesthetized, and the right gastrocnemius-plantaris (gastroc) and soleus muscles were removed. Left muscles were removed after electrical stimulation for 5 min. No significant differences were noted between treatment groups in ATP, creatine phosphate, or LKB1 activity. The α- and β-subunit isoforms were not significantly influenced in gastroc by corticosterone treatment. Expression of the γ3-subunit decreased, and γ1- and γ2-subunit expression increased. Both α2-AMPK and α1-AMPK activities were increased in the gastroc in response to electrical stimulation, but the magnitude of the increase was less for α2 in the Hypercort rats. Despite elevated plasma insulin and elevated plasma leptin in the Hypercort rats, phosphorylation of TBC1D1 was lower in both resting and stimulated muscle compared with controls. Malonyl-CoA content was elevated in gastroc muscles of resting Hypercort rats. These changes in response to excess glucocorticoids could be responsible, in part, for the decrease in insulin sensitivity and adiposity seen in Cushing's syndrome.
Age and sex influence the balance between maximal cardiac output and peripheral vascular reserve
Authors: Ridout Samuel J. , Parker Beth A. , Smithmyer Sandra L. , Gonzales Joaquin U. , Beck Kenneth C. , Proctor David N.
Published: December 2009

We evaluated the influence of age and sex on the relationship between central and peripheral vasodilatory capacity. Healthy men (19 younger, 12 older) and women (17 younger, 17 older) performed treadmill and knee extensor exercise to fatigue on separate days while maximal cardiac output (Q, acetylene uptake) and peak femoral blood flow (FBF, Doppler ultrasound) were measured, respectively. Maximal Q was reduced with age similarly in men (Y: 23.6 ± 2.7 vs. O: 17.4 ± 3.5 l/min; P < 0.05) and women (Y: 17.7 ± 1.9 vs. O: 12.3 ± 1.6 l/min; P < 0.05). Peak FBF was similar between younger (Y) and older (O) men (Y: 2.1 ± 0.5 vs. O: 2.2 ± 0.7 l/min) but was lower in older women compared with younger women (Y: 1.9 ± 0.4 vs. O: 1.4 ± 0.4 l/min; P < 0.05). Maximal Q was positively correlated with peak FBF in men (Y: r = 0.55, O: r = 0.74; P < 0.05) but not in women (Y: r = 0.34, O: r = 0.10). Normalization of cardiac output to appendicular muscle mass and peak FBF to quadriceps mass reduced the correlation between these variables in younger men ( r = 0.30), but the significant association remained in older men ( r = 0.68; P < 0.05), with no change in women. These data suggest that 1) aerobic capacity is associated with peripheral vascular reserve in men but not women, and 2) aging is accompanied by a more pronounced sex difference in this relationship.
Influence of exercise and perivascular adipose tissue on coronary artery vasomotor function in a familial hypercholesterolemic porcine atherosclerosis model
Authors: Bunker Aaron K. , Laughlin M. Harold
Published: December 2009

Our lab has shown that left circumflex coronary artery (LCX) perivascular adipose tissue (PAT) blunts endothelin-1 (ET-1)-induced maximal contractions in normal pigs on low- and high-fat diets. Other studies report that PAT exerts anticontractile effects on agonist-induced arterial contraction via release of a relaxing factor that acts on the underlying vasculature. The purpose of this study was to test the hypotheses that PAT blunts LCX contraction in familial hypercholesterolemic pigs and that exercise training (Ex) augments this anticontractile effect. Male familial hypercholesterolemic pigs were divided into Ex ( n = 13) and sedentary (Sed) ( n = 15) groups. LCX reactivity to angiotensin II (ANG II), bradykinin (BK), ET-1, and sodium nitroprusside (SNP) was evaluated in vitro with intact or removed PAT in Sed and Ex familial hypercholesterolemic pigs. LCX relaxation induced by BK and SNP was not altered by Ex or PAT removal. LCX contractions stimulated by ANG II and ET-1 were not significantly altered by Ex or PAT removal across doses; however, Ex did act to significantly reduce ET-1 maximal contractions in familial hypercholesterolemic pig LCX compared with Sed familial hypercholesterolemic pig LCX, independent of PAT ( P < 0.05). We conclude that LCX PAT in Sed and Ex familial hypercholesterolemic pigs exerts no substantial anticontractile influence over LCX vasomotor responses to endogenous constrictors such as ANG II and ET-1. Our results suggest that exercise training significantly reduces familial hypercholesterolemic pig LCX maximal contractile responses to the endogenous constrictor ET-1, independent of PAT.
Can Prenatal Screening for Fetal Alcohol Spectrum Disorder Be Justified? A Commentary
Authors: Mizejewski G.J.
Published: December 2009

Fetal alcohol spectrum disorder (FASD) is the leading cause of non-genetic mental retardation in the USA, possibly exceeding even Down syndrome, which is currently approaching 1 in 500 live births. Alcohol consumption during pregnancy results in brain, craniofacial and heart defects, neurotoxicity, and immune dysfunction. The preferred action taken to prevent alcohol consumption during pregnancy is abstinence. However, the detection, diagnosis, and treatment of FASD remain a major public health need in this country and throughout the world. The biochemical molecules involved in the developmental anomalities encompass a vast array of signal transduction and synaptic pathways which involve neurotransmitters and neurotrophic peptides. Recent advances in medicine-based therapies for FASD have been reported, and include the use of small molecule agonists, antagonists, and competitive inhibitors. Since biomarkers for FASD have previously been identified in clinical research reports, multicenter screening feasibility studies now seem warranted and could be initiated following adequate funding, protocols, procedures, and institutional review board approvals.
Allelic Heterogeneity in Genetic Association Meta-Analysis: An Application to DTNBP1 and Schizophrenia
Authors: Maher Brion S. , Reimers Mark A. , Riley Brien P. , Kendler Kenneth S.
Published: December 2009

Background/Aims: Meta-analysis of genetic association studies is a useful approach when individual investigations do not yield studywise significant results but the evidence across studies is modest and homogeneous. Current meta-analysis methods account for heterogeneity by down-weighting studies as a function of between-study variance. We contend that current approaches may obscure interesting phenomena in genetic association data. However, an appropriate approach to examining heterogeneity across studies is lacking. Methods: We develop a novel approach, based on the EM algorithm, to detect allelic heterogeneity, identify subpopulations and assign studies to those subpopulations. We then apply these methods to the association between DTNBP1 and schizophrenia (Scz), one of the most studied relationships in complex disease genetics. We examined 32 published and unpublished population and family-based association studies containing up to 14 SNPs spanning the DTNBP1 locus. Results: We explored heterogeneity in several ways including meta-regression and approaches aimed at exploring the mixture of heterogeneous studies at a particular SNP. We found significant evidence for a mixture of association distributions at multiple loci. Conclusion: We propose a novel approach that is broadly applicable and may be useful in large scale genetic association meta-analyses to detect significant allelic heterogeneity.
Parsing the Effects of Individual SNPs in Candidate Genes with Family Data
Authors: Hoffmann Thomas J. , Lange Christoph , Vansteelandt Stijn , Raby Benjamin A. , DeMeo Dawn L. , Silverman Edwin K. , Weiss Scott T. , Laird Nan M.
Published: December 2009

We introduce a stepwise approach for family-based designs for selecting a set of markers in a gene that are independently associated with the disease. The approach is based on testing the effect of a set of markers conditional on another set of markers. Several likelihood-based approaches have been proposed for special cases, but no model-free based tests have been proposed. We propose two types of tests in a family-based framework that are applicable to arbitrary family structures and completely robust to population stratification. We propose methods for ascertained dichotomous traits and unascertained quantitative traits. We first propose a completely model-free extension of the FBAT main genetic effect test. Then, for power issues, we introduce two model-based tests, one for dichotomous traits and one for continuous traits. Lastly, we utilize these tests to analyze a continuous lung function phenotype as a proxy for asthma in the Childhood Asthma Management Program. The methods are implemented in the free R package fbati.
Statistical Tests of Genetic Association in the Presence of Gene-Gene and Gene-Environment Interactions
Authors: Pan Wei
Published: December 2009

Background: While its importance is well recognized, it remains challenging to test genetic association in the presence of gene-gene (or gene-environment) interactions. A major technical difficulty lies in the fact that a general model of gene-gene interactions calls for the use of often a large number of parameters, leading to possibly reduced statistical power. An emerging theme of some recent work is to reduce the number of such parameters through dimension reduction. Wang et al. [2009] proposed such an approach based on the partial least squares (PLS) for dimension reduction. They compared their method with several others using simulated data, establishing that their PLS test performed best. Unfortunately, Wang et al. did not include in their evaluations several powerful tests just recently discovered for analyzing multiple SNPs in a candidate gene or region. Methods: In this paper, we first extend these tests to the current context to detect gene-gene interactions in the presence of nuisance parameters, then compare these tests with the PLS test using the simulated data of Wang et al. [2009]. Results: It is confirmed that some other tests can be more powerful than the PLS test, though there is no uniform winner. Some interesting, albeit not new, observations are also made: some of the new tests are more robust to the large number of parameters in a model and may thus perform well; on the other hand, even for a purely epistatic genetic model, some of the tests applied to a logistic main-effects model without any interaction terms may be superior to that based on a full model that explicitly accounts for gene-gene interactions. Conclusion: The proposed statistical tests are potentially useful in practice.
Liver Transplantation Exceeding UCSF Criteria: Case Report of a Late Recurrence Treated by Surgery and Review of the Literature
Authors: Piardi T. , Audet M. , Odeh M. , Panaro F. , Cag M. , El-ahmar J. , Baiocchi G.L. , Schneider A. , Wolf P.
Published: December 2009

Introduction: Treatment of a recurrence of hepatocellular carcinoma (HCC) after liver transplantation. Surgery has seldom been considered in such a situation because HCC recurrences are generally considered as a systemic disease. Patient and Methods: We describe a 47-year-old male patient who underwent liver transplantation in October 1999 for HCC exceeding the Milan and University of California, San Francisco (UCSF), criteria. Results: In 2007 (8 years after liver transplantation), the patient developed a cervical bone metastasis treated by surgery. In April 2008, HCC had disseminated to hepatic pedicle lymph nodes. An extended hepatic pedicle lymphadenectomy was then performed. Today, our patient is doing well, without signs of recurrence. Discussion: The risk of developing a tumor recurrence is the main argument against expanding the UCSF criteria. In case of an HCC recurrence, various treatments ranging from a change in the immunosuppression regimen to chemotherapy have been proposed. Surgical treatment has rarely been envisaged in the treatment of HCC recurrences because of the technical difficulties and the frequent dissemination of cancer.
Retrosigmoid Keyhole Approach to the Posterior Cranial Fossa: An Anatomical and Clinical Study
Authors: Li Z. , Lan Q.
Published: December 2009

The purpose of this study is to describe the microsurgical anatomic features, as well as the operative technique for the retrosigmoid keyhole (RSK) approach to the posterior cranial fossa. In the anatomical study, 6 cadaveric heads were dissected to simulate the RSK approach. In the clinical study, the records for 15 patients treated using the RSK approach were examined. We found both conventional and RSK procedures expose the regions superior to the anterolateral margin of the tentorium, inferior to the foramen magnum, and medial to the anterolateral pons and medulla. Clinically, total removal was achieved in 13 out of 15 patients. We feel it is a safe, succinct, and minimally invasive alternative to the traditional retrosigmoid approach in selected patients.
Cryptogenic Hemoptysis in Chronic Obstructive Pulmonary Disease: Characteristics and Outcome
Authors: Delage Antoine , Tillie-Leblond Isabelle , Cavestri Béatrice , Wallaert Benoit , Marquette Charles-Hugo
Published: December 2009

Background: Hemoptysis is a common presenting symptom and cause of hospitalization in the department of respiratory diseases. In a number of patients with chronic obstructive pulmonary disease (COPD) presenting with this symptom, investigations fail to reveal a precise etiology. Little data are available regarding characteristics and outcome of COPD patients presenting with cryptogenic hemoptysis (CH). Objectives: Our study goal was to assess the functional characteristics of these subjects, the risk factors for CH and the severity of hemoptysis, as well as long-term outcome. Methods: For more than 1 year, we enrolled and followed a group of 39 consecutive COPD patients admitted to our center with CH. Results: Between 1988 and 2003, 39 patients with COPD were admitted for CH in which investigation failed to reveal an etiology. The mean age was 51.3 years. All subjects were active smokers. Twenty-one patients (54%) had at least 1 risk factor for prolonged bleeding. Patients with more severe airflow obstruction tended to have more severe bleeding. Bronchoscopy appeared as useful as a computed tomography in locating the bleeding site. Arterial embolization succeeded in controlling bleeding in all patients who underwent angiography. One patient experienced a relapse in bleeding at 2 months. One developed lung cancer after 1 year. Thirty-four patients were followed for an average of 5 years. Only 2 subjects experienced recurrent hemoptysis. None died. Conclusions: CH in patients with COPD is associated with a favorable short- and long-term outcome when managed with timely angiographic embolization. Long-term incidence of lung cancer was uncommon after an episode of CH, and recurrences of hemoptysis were rare.
Effects of Acute Blood Volume Expansion on Respiratory Mechanics in the Rat
Authors: Rubini A. , Gasperetti A. , Catena V. , Del Monte D.
Published: December 2009

Backgrounds: The effects of acute blood volume expansion (BVE) on the respiratory mechanics of normal animals have been not extensively studied. The subject is of both theoretical and practical interest since BVE is a frequent medical intervention, and the associated increase in cardiac output may occur in different physiopathological situations. Objectives: To describe the changes in the parameters of respiratory mechanics occurring as an effect of acute BVE and the related increase in cardiac output. Methods: We applied the end-inflation occlusion method in normal, positive pressure-ventilated rats to measure the respiratory mechanics under control and BVE conditions. Results: Under BVE conditions, we found a statistically significant increase in static respiratory system elastance (Est,rs), ohmic airway resistance plus resistance of respiratory system tissues to movement (Rmin,rs), and overall resistance including pendelluft and stress relaxation effects (Rmax,rs). Under BVE conditions, the resistive component due to sole stress relaxation and pendelluft (Rvisc,rs) increased almost significantly while a significant increment in mean respiratory system hysteresis surface area (Hyrs) was also found. Conclusions: Increasing pulmonary blood flow by BVE increases the mechanical work of breathing because of the effects on Est,rs, Rmin,rs and Rmax,rs, and because of the increase in Hyrs.
Mechano-Sensitive Transcriptional Factor Egr-1 Regulates Insulin-Like Growth Factor-1 Receptor Expression and Contributes to Neointima Formation in Vein Grafts
Authors: Wu Xiaoqian , Cheng Jizhong , Li Ping , Yang Min , Qiu Shulan , Liu Peiqing , Du Jie
Published: December 2009

Objective—

Vein grafts in a coronary bypass or a hemodialysis access often develop obliterative growth of the neointima. We previously reported that the mechanical stretch-activated insulin-like growth factor-1 receptor (IGF-1/IGF-1R) pathway plays an important role in this remodeling. However, the transcriptional mechanism(s) regulating IGF-1R expression and neointima formation have not been identified.

Methods and Results—

Deletion and site-specific mutagenesis analysis of IGF-1R promoter identified that the minimal mechano-responsive promoter element (−270–−130) contains 2 consensus sequences for binding of early growth reponse-1 (Egr-1) transcriptional factor. Mechanical stretch stimulated both Egr-1 mRNA (4.6-fold) and protein (5.2-fold) in vascular smooth muscle cells. Interposition of a vein into an artery increased Egr-1 mRNA (7.8±2.6-fold vs sham). In vascular smooth muscle cells isolated from Egr-1 knockout mice, mechanical stretch could not increase IGF-1R, and vascular smooth muscle cells proliferation was decreased by 47% compared to wild-type cells. Importantly, the neointima area was reduced by at least 50%, and the lumen-to-media ratio increased by 55% in vein grafts of Egr-1 knockout mice compared with results of wild-type mice.

Conclusion—

Egr-1 is a mechano-sensitive transcriptional factor that stimulates IGF-1R transcription, resulting in vascular remodeling of vein grafts.
Human Sickle Cell Blood Modulates Endothelial Heme Oxygenase Activity
Authors: Bains Sandip K. , Foresti Roberta , Howard Jo , Atwal Sangeeta , Green Colin J. , Motterlini Roberto
Published: December 2009

Objective—

Sickle cell disease (SCD) is characterized by extensive hemolysis, increased cellular adhesion, and vaso-occlusion. Tissues from sickle patients express heme oxygenase-1 (HO-1), the enzyme that degrades free heme/hemoglobin to the signaling molecule carbon monoxide, and the antioxidants biliverdin/bilirubin. Here, we examined the HO response in endothelial cells exposed to human sickle blood and determined whether this response is beneficial for SCD.

Methods and Results—

We measured HO activity in human and bovine aortic endothelial cells incubated with human sickle or normal blood. Sickle blood increased HO activity, which was enhanced by hypoxia and was caused mainly by the red cell components of sickle blood. Oxidized hemoglobin was higher in sickle blood and increased markedly over time. Interestingly, HO activity correlated inversely with patients’ hemoglobin levels and positively with bilirubin and lactate dehydrogenase. HO-1 induction, exogenous biliverdin, or carbon monoxide markedly decreased adhesion of sickle blood to the endothelium, and sickle red cells partially inhibited relaxation mediated by carbon monoxide in isolated aortas.

Conclusions—

Our results highlight important associations between SCD and HO byproducts, which may counteract vascular complications of SCD.
Identification of Two Common Variants Contributing to Serum Apolipoprotein B Levels in Mexicans
Authors: Weissglas-Volkov Daphna , Plaisier Christopher L. , Huertas-Vazquez Adriana , Cruz-Bautista Ivette , Riaño-Barros Daniela , Herrera-Hernandez Miguel , Riba Laura , Cantor Rita M. , Sinsheimer Janet S. , Aguilar-Salinas Carlos A. , Tusie-Luna Teresa , Pajukanta Päivi
Published: December 2009

Background and Purpose—

Although the Mexican population has a high predisposition to dyslipidemias and premature coronary artery disease, this population is underinvestigated for the genetic factors conferring the high susceptibility. This study attempted to determine these genetic factors.

Methods and Results—

First, we investigated apolipoprotein B (apoB) levels in Mexican extended families with familial combined hyperlipidemia using a two-step testing strategy. In the screening step, we screened 5721 single-nucleotide polymorphisms (SNPs) for linkage signals with apoB. In the test step, we analyzed the 130 SNPs residing in regions of suggestive linkage signals for association with apoB. We identified significant associations with two SNPs (ie, rs1424032 [
P
=6.07×10
−6
] and rs1349411 [
P
=2.72×10
−4
]) that surpassed the significance level for the number of tests performed in the test step (
P
<3.84×10
−4
). Second, these SNPs were tested for replication in Mexican hyperlipidemic case-control samples. The same risk alleles as in the families with familial combined hyperlipidemia were significantly associated (
P
<0.05) with apoB in the case-control samples. The rs1349411 resides near the apoB messenger RNA editing enzyme (
APOBEC1
) involved in the processing of
APOB
messenger RNA in the small intestine. The rs1424032 resides in a highly conserved noncoding region predicted to function as a regulatory element.

Conclusion—

We identified two novel variants, rs1349411 and rs1424032, for serum apoB levels in Mexicans.
Is Sticky Blood Bad for the Brain?
Authors: Gallacher John , Bayer Antony , Lowe Gordon , Fish Mark , Pickering Janet , Pedro Sofia , Dunstan Frank , White James , Yarnell John , Ben-Shlomo Yoav
Published: December 2009

Objective—

Hemostasis and inflammation have been implicated in dementia. This study investigates the role of specific hemostatic and inflammatory pathways with incident vascular and nonvascular dementia.

Methods and Results—

This was a prospective study of a population sample of men aged 65 to 84 years, with baseline assessment of hemostatic and inflammatory factors and cognition measured 17 years later. The sample included 865 men (59 had dementia and 112 had cognitive impairment, not dementia), free of vascular disease at baseline and for whom hemostatic and inflammatory marker data were available and cognitive status was known. A total of 15 hemostatic and 6 inflammatory markers were assessed. Factor analysis was used to identify hemostatic subsystems. The National Institute of Neurological Disorders and Stroke–Association Internationale pour la Recherche et l’Enseignement en Neurologie criteria were used to identify vascular dementia. By using standardized (
z
) scores for hemostatic and inflammatory markers, and after adjustment for age and risk factors, vascular dementia was associated with fibrinogen (hazard ratio [HR], 1.68; 95% confidence interval [CI], 1.02–2.76), factor VIII (HR, 1.79; 95% CI, 1.09–3.00), and plasminogen activator inhibitor 1 (HR, 3.13; 95% CI, 1.73–5.70). For vascular dementia, the HR risk from high levels of all three hemostatic variables (fibrinogen, factor VIII, and plasminogen activator inhibitor 1) was 2.97 (
P
<0.001). Inflammatory factors were not associated with vascular dementia.

Conclusion—

The associations of these hemostatic markers with vascular dementia may implicate clot formation as the primary mechanism and are consistent with a microinfarct model of vascular dementia.
Atorvastatin Inhibits gp91phoxCirculating Levels in Patients With Hypercholesterolemia
Authors: Pignatelli Pasquale , Carnevale Roberto , Cangemi Roberto , Loffredo Lorenzo , Sanguigni Valerio , Stefanutti Claudio , Basili Stefania , Violi Francesco
Published: December 2009

Objective—The inhibition of oxidative stress is among the most relevant pleiotropic effects of statins. The mechanism by which statins exert their antioxidant effect in vivo is still undefined. NADPH oxidase is among the most important sources of reactive oxygen species involved in atherosclerotic disease.

Methods/Results—We developed an ELISA to evaluate serum levels of soluble-gp91phox, the catalytic core of phagocyte NADPH oxidase. In a cross-sectional study performed in 30 hypercholesterolemic patients and in 20 controls, serum soluble-gp91phoxand urinary isoprostane, a marker of oxidative stress, were measured. The 2 variables were also measured in hypercholesterolemic patients, randomized to diet (n=15), or diet plus atorvastatin (10 mg daily, n=15) and followed for 30 days. Compared to controls, hypercholesterolemic patients had higher and significantly correlated (R=0.71;P<0.001) serum soluble-gp91phox(P<0.001) and urinary isoprostanes (P<0.001). After follow-up, the statin-allocated group showed a significant reduction of soluble-gp91phox(−33%,P<0.01), that paralleled that of isoprostanes (−37%,P<0.01) and cholesterol (−25%,P<0.01). The diet-allocated group showed only a weak reduction of cholesterol.

Conclusion—Our study demonstrates that statins exert an antioxidant effect via inhibition of soluble gp91phoxexpression.
Pharmacological Inhibition of C-C Chemokine Receptor 2 Decreases Macrophage Infiltration in the Aortic Root of the Human C-C Chemokine Receptor 2/Apolipoprotein E
−/−
Mouse: Magnetic Resonance Imaging Assessment
Authors: Olzinski Alan R. , Turner Gregory H. , Bernard Roberta E. , Karr Heather , Cornejo Carla A. , Aravindhan Karpagam , Hoang Bao , Ringenberg Michael A. , Qin Pu , Goodman Krista B. , Willette Robert N. , Macphee Colin H. , Jucker Beat M. , Sehon Clark A. , Gough Peter J.
Published: December 2009

Purpose—

This study assessed the pharmacological effect of a novel selective C-C chemokine receptor (CCR) 2 antagonist (GSK1344386B) on monocyte/macrophage infiltration into atherosclerotic plaque using magnetic resonance imaging (MRI) in an atherosclerotic mouse model.

Methods and Results—

Apolipoprotein E
−/−
mice expressing human CCR2 were fed a Western diet (vehicle group) or a Western diet plus10 mg/kg per day of GSK1344386B (GSK1344386B group). After the baseline MRI, mice were implanted with osmotic pumps containing angiotensin II, 1000 ng/kg per minute, to accelerate lesion formation. After five weeks of angiotensin II administration, mice received ultrasmall superparamagnetic iron oxide, an MRI contrast agent for the assessment of monocyte/macrophage infiltration to the plaque, and underwent imaging. After imaging, mice were euthanized, and the heart and aorta were harvested for ex vivo MRI and histopathological examination. After 5 weeks of dietary dosing, there were no significant differences between groups in body or liver weight or plasma cholesterol concentrations. An in vivo MRI reflected a decrease in ultrasmall superparamagnetic iron oxide contrast agent uptake in the aortic arch of the GSK1344386B group (
P
<0.05). An ex vivo MRI of the aortic root also reflected decreased ultrasmall superparamagnetic iron oxide uptake in the GSK1344386B group and was verified by absolute iron analysis (
P
<0.05). Although there was no difference in aortic root lesion area between groups, there was a 30% reduction in macrophage area observed in the GSK1344386B group (
P
<0.05).

Conclusion—

An MRI was used to noninvasively assess the decreased macrophage content in the atherosclerotic plaque after selective CCR2 inhibition.
Nuclear Factor of Activated T Cells Regulates Osteopontin Expression in Arterial Smooth Muscle in Response to Diabetes-Induced Hyperglycemia
Authors: Nilsson-Berglund Lisa M. , Zetterqvist Anna V. , Nilsson-Öhman Jenny , Sigvardsson Mikael , González Bosc Laura V. , Smith Maj-Lis , Salehi Albert , Agardh Elisabet , Fredrikson Gunilla Nordin , Agardh Carl-David , Nilsson Jan , Wamhoff Brian R. , Hultgårdh-Nilsson Anna , Gomez Maria F.
Published: December 2009

Objective—

Hyperglycemia is a recognized risk factor for cardiovascular disease in diabetes. Recently, we reported that high glucose activates the Ca
2+
/calcineurin-dependent transcription factor nuclear factor of activated T cells (NFAT) in arteries ex vivo. Here, we sought to determine whether hyperglycemia activates NFAT in vivo and whether this leads to vascular complications.

Methods and Results—

An intraperitoneal glucose-tolerance test in mice increased NFATc3 nuclear accumulation in vascular smooth muscle. Streptozotocin-induced diabetes resulted in increased NFATc3 transcriptional activity in arteries of NFAT-luciferase transgenic mice. Two NFAT-responsive sequences in the osteopontin (OPN) promoter were identified. This proinflammatory cytokine has been shown to exacerbate atherosclerosis and restenosis. Activation of NFAT resulted in increased OPN mRNA and protein in native arteries. Glucose-induced OPN expression was prevented by the ectonucleotidase apyrase, suggesting a mechanism involving the release of extracellular nucleotides. The calcineurin inhibitor cyclosporin A or the novel NFAT blocker A-285222 prevented glucose-induced OPN expression. Furthermore, diabetes resulted in higher OPN expression, which was significantly decreased by in vivo treatment with A-285222 for 4 weeks or prevented in arteries from NFATc3
−/−
mice.

Conclusions—

These results identify a glucose-sensitive transcription pathway in vivo, revealing a novel molecular mechanism that may underlie vascular complications of diabetes.
L-4F Alters Hyperlipidemic (But Not Healthy) Mouse Plasma to Reduce Platelet Aggregation
Authors: Buga Georgette M. , Navab Mohamad , Imaizumi Satoshi , Reddy Srinivasa T. , Yekta Babak , Hough Greg , Chanslor Shawn , Anantharamaiah G.M. , Fogelman Alan M.
Published: December 2009

Background and Purpose—

Hyperlipidemia is associated with platelet hyperreactivity. We hypothesized that L-4F, an apolipoprotein A-I mimetic peptide, would inhibit platelet aggregation in hyperlipidemic mice.

Methods and Results—

Injecting L-4F into apolipoprotein E (apoE)–null and low-density lipoprotein receptor–null mice resulted in a significant reduction in platelet aggregation in response to agonists; however, there was no reduction in platelet aggregation after injection of L-4F into wild-type (WT) mice. Consistent with these results, injection of L-4F into apoE-null mice prolonged bleeding time; the same result was not found in WT mice. Incubating L-4F in vitro with apoE-null platelet-rich plasma also resulted in decreased platelet aggregation. However, incubating washed platelets from either apoE-null or WT mice with L-4F did not alter aggregation. Compared with WT mice, unstimulated platelets from apoE-null mice contained significantly more 12-hydroxy 5,8,10,14-eicosatetraenoic acid, thromboxane A
2
, and prostaglandins D
2
and E
2
. In response to agonists, platelets from L-4F–treated apoE-null mice formed significantly less thromboxane A
2
, prostaglandins D
2
and E
2
, and 12-hydroxy 5,8,10,14-eicosatetraenoic acid.

Conclusion—

By binding plasma-oxidized lipids that cause platelet hyperreactivity in hyperlipidemic mice, L-4F decreases platelet aggregation.
The 5A Apolipoprotein A-I Mimetic Peptide Displays Antiinflammatory and Antioxidant Properties In Vivo and In Vitro
Authors: Tabet Fatiha , Remaley Alan T. , Segaliny Aude I. , Millet Jonathan , Yan Ling , Nakhla Shirley , Barter Philip J. , Rye Kerry-Anne , Lambert Gilles
Published: December 2009

Objectives—

The apolipoprotein (apo)A-I mimetic peptide 5A is highly specific for ATP-binding cassette transporter (ABC)A1-mediated cholesterol efflux. We investigated whether the 5A peptide shares other beneficial features of apoA-I, such as protection against inflammation and oxidation.

Methods—

New Zealand white rabbits received an infusion of apoA-I, reconstituted high-density lipoprotein (HDL) containing apoA-I ([A-I]rHDL), or the 5A peptide complexed with phospholipids (1-palmitoyl-2-linoleoyl phosphatidylcholine [PLPC]), before inserting a collar around the carotid artery. Human coronary artery endothelial cells (HCAECs) were incubated with (A-I)rHDL or 5A/PLPC before stimulation with tumor necrosis factor α.

Results—

ApoA-I, (A-I)rHDL, and 5A/PLPC reduced the collar-mediated increase in (1) endothelial expression of cell adhesion molecules vascular cell adhesion molecule-1 and intercellular adhesion molecule-1; (2)

production, as well as the expression of the Nox4 catalytic subunits of the NADPH oxidase; and (3) infiltration of circulating neutrophils into the carotid intima–media. In HCAECs, both 5A/PLPC and (A-I)rHDL inhibited tumor necrosis factor-α–induced intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression, as well as the nuclear factor κB signaling cascade and

production. The effects of the 5A/PLPC complex were no longer apparent in HCAECs knocked down for ABCA1.

Conclusion—

Like apoA-I, the 5A peptide inhibits acute inflammation and oxidative stress in rabbit carotids and HCAECs. In vitro, the 5A peptide exerts these beneficial effects through interaction with ABCA1.
Context-Dependent Associations Between Variation in Risk of Ischemic Heart Disease and Variation in the 5′ Promoter Region of the
Apolipoprotein E
Gene in Danish Women
Authors: Stengård Jari H. , Dyson Greg , Frikke-Schmidt Ruth , Tybj�rg-Hansen Anne , Nordestgaard Borge G. , Sing Charles F.
Published: December 2009

Objective—

Variations in the noncoding single-nucleotide polymorphisms (SNPs) at positions 560 and 832 in the 5′ promoter region of the
apolipoprotein E
gene define genotypes that distinguish between high and low concentrations of plasma total and high-density lipoprotein cholesterol and triglycerides. We addressed whether these genotypes improve the prediction of ischemic heart disease (IHD) in subsamples of individuals defined by traditional risk factors and the genotypes defined by the ε

2

, ε

3

, and ε

4

alleles in exon 4 of the
apolipoprotein E
gene.

Methods and Results—

In a sample of 3686 female and 2772 male participants of the Copenhagen City Heart Study who were free of IHD events, 576 individuals (257 women, 7.0% and 319 men, 11.5%) were diagnosed as having developed IHD in 6.5 years of follow-up. Using a stepwise Patient Rule-Induction Method modeling strategy that acknowledges the complex pathobiology of IHD, we identified a subsample of 764 elderly women (≥65 years) with hypertriglyceridemia who had a history of smoking, a history of hypertension, or a history of both in which the
A

560

T

832

/A

560

T

832

and
A

560

T

832

/A

560

G

832

5′ 2-SNP genotypes had a higher cumulative incidence of IHD (172/1000) compared to the incidence of 70/1000 in the total sample of women.

Conclusions—

Our study validates that 5′
apolipoprotein E
genotypes improve the prediction of IHD and documents that the improvement is greatest in a subset defined by a particular combination of traditional risk factors in Copenhagen City Heart Study female participants. We discuss the use of these genotypes in medical risk assessment of IHD in the population represented by the Copenhagen City Heart Study.
Regional Very Low Cerebral Blood Volume Predicts Hemorrhagic Transformation Better Than Diffusion-Weighted Imaging Volume and Thresholded Apparent Diffusion Coefficient in Acute Ischemic Stroke
Authors: Campbell Bruce C.V. , Christensen Søren , Butcher Kenneth S. , Gordon Ian , Parsons Mark W. , Desmond Patricia M. , Barber P. Alan , Levi Christopher R. , Bladin Christopher F. , De Silva Deidre A. , Donnan Geoffrey A. , Davis Stephen M.
Published: December 2009

Background and Purpose—

Currently, diffusion-weighted imaging (DWI) lesion volume is the most useful magnetic resonance imaging predictor of hemorrhagic transformation (HT). Preliminary studies have suggested that very low cerebral blood volume (VLCBV) predicts HT. We compared HT prediction by VLCBV and DWI using data from the EPITHET study.

Methods—

Normal-percentile CBV values were calculated from the nonstroke hemisphere. Whole-brain masks with CBV thresholds of the <0, 2.5, 5, and 10th percentiles were created. The volume of tissue with VLCBV was calculated within the acute DWI ischemic lesion. HT was graded as per ECASS criteria.

Results—

HT occurred in 44 of 91 patients. Parenchymal hematoma (PH) occurred in 13 (4 symptomatic) and asymptomatic hemorrhagic infarction (HI) in 31. The median volume of VLCBV was significantly higher in cases with PH. VLCBV predicted HT better than DWI lesion volume and thresholded apparent diffusion coefficient lesion volume in receiver operating characteristic analysis and logistic regression. A cutpoint at 2 mL VLCBV with the <2.5th percentile had 100% sensitivity for PH and, in patients treated with tissue plasminogen activator, defined a population with a 43% risk of PH (95% CI, 23% to 66%, likelihood ratio=16). VLCBV remained an independent predictor of PH in multivariate analysis with traditional clinical risk factors for HT.

Conclusions—

VLCBV predicted HT after thrombolysis better than did DWI or apparent diffusion coefficient volume in this large patient cohort. The advantage was greatest in patients with smaller DWI volumes. Prediction was better in patients who recanalized. If validated in an independent cohort, the addition of VLCBV to prethrombolysis decision making may reduce the incidence of HT.
Cerebral Flow Velocities During Daily Activities Depend on Blood Pressure in Patients With Chronic Ischemic Infarctions
Authors: Novak Vera , Hu Kun , Desrochers Laura , Novak Peter , Caplan Louis , Lipsitz Lewis , Selim Magdy
Published: December 2009

Background and Purpose—

Target blood pressure (BP) values for optimal cerebral perfusion after an ischemic stroke are still debated. We sought to examine the relationship between BP and cerebral blood flow velocities (BFVs) during daily activities.

Methods—

We studied 43 patients with chronic large vessel ischemic infarctions in the middle cerebral artery territory (aged 64.2±8.94 years; at 6.1±4.9 years after stroke) and 67 age-matched control subjects. BFVs in middle cerebral arteries were measured during supine baseline, sitting, standing, and tilt. A regression analysis and a dynamic phase analysis were used to quantify the BP–BFV relationship.

Results—

The mean arterial pressure was similar between the groups (89±15 mm Hg). Baseline BFVs were lower by approximately 30% in the patients with stroke compared with the control subjects (
P
=0.0001). BFV declined further with postural changes and remained lower in the stroke group during sitting (
P
=0.003), standing (
P
=0.003), and tilt (
P
=0.002) as compared with the control group. Average BFVs on the stroke side were positively correlated with BP during baseline (
R
=0.54,
P
=0.0022, the slope 0.46 cm/s/mm Hg) and tilt (
R
=0.52,
P
=0.0028, the slope 0.40 cm/s/mm Hg). Regression analysis suggested that BFV may increase approximately 30% to 50% at mean BP >100 mm Hg. Orthostatic hypotension during the first minute of tilt or standing was independently associated with lower BFV on the stroke side (
P
=0.0008). Baseline BP–BFV phase shift derived from the phase analysis was smaller on the stroke side (
P
=0.0006).

Conclusion—

We found that BFVs are lower in patients with stroke and daily activities such as standing could induce hypoperfusion. BFVs increase with mean arterial pressure >100 mm Hg. Dependency of BFV on arterial pressure may have implications for BP management after stroke. Further prospective investigations are needed to determine the impact of these findings on functional recovery and strategies to improve perfusion pressure during daily activities after ischemic stroke.