bluuebunny/crossref_metadata_2025 huggingface dataset:
Intimal Smooth Muscle Cells as a Target for Peroxisome Proliferator-Activated Receptor-γ Ligand Therapy
Authors: Bishop-Bailey David , Hla Timothy , Warner Timothy D.
Published: October 2002

Activation of the nuclear receptor/transcription factor, peroxisome proliferator-activated receptor γ (PPARγ), is a newly defined target for limiting vascular pathologies. PPARγ is expressed in human and animal models of vascular disease, with particularly high levels being present in the cells of the neointimal microenvironment. In the present study, we show that intimal smooth muscle cells in vitro contain higher amounts of functional PPARγ than medial smooth muscle cells. The PPARγ ligand rosiglitazone more potently induced CD36 expression at low concentrations, and cell death by apoptosis at higher concentrations in intimal compared with medial smooth muscle cells. Intimal smooth muscle cells also contained high levels of cyclooxygenase-2 protein, and released a more diverse and larger amount of eicosanoids on arachidonic acid stimulation. Furthermore, when exogenous arachidonic acid was added, PPAR reporter gene activation was induced in a cyclooxygenase inhibitor–sensitive manner, an effect that correlated with an increase in CD36 expression. In summary, intimal smooth muscle cells contain functionally higher levels of PPARγ, PPARγ ligands have high- and low-potency targets in vascular smooth muscle cells, and cyclooxygenase can serve as a source of potential endogenous PPAR ligands. Intimal vascular smooth muscle cells therefore represent a potentially important target for the antiproliferative, and antiatherosclerotic actions of PPARγ ligands.
Short-Term Treatment With Ranolazine Improves Mechanical Efficiency in Dogs With Chronic Heart Failure
Authors: Chandler Margaret P. , Stanley William C. , Morita Hideaki , Suzuki George , Roth Bridgette A. , Blackburn Brent , Wolff Andrew , Sabbah Hani N.
Published: October 2002

The present study assesses whether ranolazine increases left ventricular (LV) function without an increase in myocardial oxygen consumption (MV̇
o
2
) and thus improves LV mechanical efficiency in dogs with heart failure (HF). Ranolazine did not change MV̇
o
2
and LV mechanical efficiency increased (22.4±2.8% to 30.9±3.4% (
P
<0.05). In contrast, dobutamine significantly increased MV̇
o
2
and did not improve mechanical efficiency. Thus, short-term treatment with ranolazine improved LV function without an increase in MV̇
o
2
, resulting in an increased myocardial mechanical efficiency in dogs with HF.
Depressed Ryanodine Receptor Activity Increases Variability and Duration of the Systolic Ca
2+
Transient in Rat Ventricular Myocytes
Authors: Díaz M.E. , Eisner D.A. , O’Neill S.C.
Published: October 2002

Sarcoplasmic reticulum (SR) Ca
2+
release, through the ryanodine receptor (RyR), is essential for the systolic Ca
2+
transient and thus the cardiac contractile function. The aim of this study was to examine the effects on the spatial organization of the systolic Ca
2+
transient of depressing RyR open probability (P
o
) with tetracaine or intracellular acidification. Voltage-clamped, fluo-3–loaded myocytes were studied using confocal microscopy. Depressing RyR P
o
increased the variability of the Ca
2+
transient amplitude between different regions of the cell. This variability often produced alternans with a region producing large and small transients alternately. In addition, the raising phase of the Ca
2+
transient became biphasic. The initial phase was constant but the second was variable and propagated as a wave through part of the cell. That both phases involved SR Ca
2+
release was shown by their reduction by caffeine. Regional [Ca
2+
]
i
alternans was accompanied by a much smaller degree of alternans at the whole cell level. We suggest that, in tetracaine or acidosis, the initial phase of the Ca
2+
transient results from Ca
2+
release via RyRs directly activated by adjacent L-type Ca
2+
channels. At some sites, this will activate neighboring RyRs and a Ca
2+
wave will propagate via activation of other RyRs. This work is the first demonstration that decreased RyR P
o
alone can produce disarray of the Ca
2+
release process and initiate alternans.
Decreasing Cellular Hydrogen Peroxide With Catalase Mimics the Effects of Hypoxia on the Sensitivity of the L-Type Ca
2+
Channel to β-Adrenergic Receptor Stimulation in Cardiac Myocytes
Authors: Hool Livia C. , Arthur Peter G.
Published: October 2002

In cardiac myocytes, hypoxia inhibits the basal L-type Ca
2+
current (
I
Ca-L
) and increases the sensitivity of
I
Ca-L
to β-adrenergic receptor stimulation. We investigated whether hydrogen peroxide (H
2
O
2
) is involved in the hypoxic response. Guinea pig ventricular myocytes were dialyzed with catalase, which specifically catalyzes the conversion of H
2
O
2
to H
2
O and oxygen, and then
I
Ca-L
was recorded during exposure to isoproterenol (Iso). Catalase decreased the
K
0.5
for activation of
I
Ca-L
by Iso from 2.7±0.3 nmol/L (in cells dialyzed with heat-inactivated catalase) to 0.4±0.1 nmol/L. The increase in sensitivity to Iso by catalase may be attenuated when cells are preexposed to H
2
O
2
. A significant increase in sensitivity of
I
Ca-L
to Iso was recorded when mitochondrial function was inhibited with myxothiazol or FCCP, suggesting that the source of H
2
O
2
was from the mitochondria. Prior exposure of cells to H
2
O
2
attenuated the inhibition of basal
I
Ca-L
during hypoxia and the increase in sensitivity of
I
Ca-L
to Iso during hypoxia. Additionally, extracellularly applied catalase mimicked the effect of hypoxia on basal
I
Ca-L
. Measurement of the rate of production of hydrogen peroxide using 5- (and 6-)chloromethyl-2′, 7′-dichlorodihydrofluorescein diacetate acetyl ester indicated that hypoxia was associated with a significant decrease in the production of hydrogen peroxide in the cells. These data suggest that hypoxia mediates changes in channel activity through a lowering in H
2
O
2
levels and that H
2
O
2
is a key intermediate in modifying basal channel activity and the β-adrenergic responsiveness of the channel during hypoxia.
c-Jun N-Terminal Kinase Activation Mediates Downregulation of Connexin43 in Cardiomyocytes
Authors: Petrich Brian G. , Gong Xiaohua , Lerner Deborah L. , Wang Xin , Brown Joan Heller , Saffitz Jeffrey E. , Wang Yibin
Published: October 2002

Loss of gap junctions and impaired intercellular communication are characteristic features of pathological remodeling in heart failure as a result of stress or injury, yet the underlying regulatory mechanism has not been identified. Here, we report that in cultured myocytes, rapid loss of the gap junction protein connexin43 (Cx43) occurs in conjunction with the activation of c-Jun N-terminal kinase (JNK), a stress-activated protein kinase, on stress stimulation. To investigate the specific role of JNK activation in the regulation of connexin in cardiomyocytes, an activated mutant of mitogen-activated protein kinase kinase 7 (mutant D), a JNK-specific upstream activator, was expressed in myocytes by adenovirus-mediated gene transfer. JNK activation in infected cardiomyocytes resulted in significant reduction of Cx43 expression at both mRNA and protein levels and impaired cell-cell communication. To evaluate the role of JNK in the regulation of Cx43 expression and gap junction structure in vivo, a Cre-LoxP–mediated gene-switch system was used to establish a transgenic animal model with targeted activation of JNK in ventricular myocardium. The transgenic hearts exhibited significant downregulation of Cx43 expression and loss of gap junctions in myocardium that may contribute to the cardiac dysfunction and premature death phenotype. Our report represents the first evidence, both in vitro and in vivo, implicating JNK as an important mediator of stress-induced Cx43 downregulation and impaired intercellular communication in the failing heart.
Serial Analysis of Gene Expression
Authors: Patino Willmar D. , Mian Omar Y. , Hwang Paul M.
Published: October 2002

It has been 7 years since serial analysis of gene expression (SAGE) and microarray hybridization techniques were simultaneously introduced to allow the screening of thousands of expressed genes. Both techniques have stood up to the test of time as evidenced by their widespread use, and both have been used for studying cardiovascular diseases. SAGE has been used more extensively to study cancer cells, but it has also been used to examine gene expression in systems as divergent as rice seedlings, yeast, and
Caenorhabditis elegans
. In this review, a summary of the advances in SAGE technology and its unique attributes and potential applications to the cardiovascular system will be presented.
DNA Microarrays
Authors: Cook Stuart A. , Rosenzweig Anthony
Published: October 2002

Dramatic progress has been made in the technologies available to assess global alterations in mRNA levels in both clinical and research samples. Through commercial services and institutional core laboratories, these technologies are increasingly accessible to individual investigators. Although such transcript profiling can provide a powerful research tool, the broad range of options can be bewildering for the uninitiated and more often than not the limitations and pitfalls of this approach are not fully appreciated. Moreover, consensus standards for data collection, analysis, and validation have yet to emerge. It is important to recognize that the goals of transcript profiling experiments can be quite diverse. These goals range from hypothesis generation and identification of novel therapeutic targets to delineation of complex patterns of gene expression that provide a potentially pathognomonic molecular phenotype. We will first present a practical review of the commonly used approaches for data collection and analysis, and discuss possible standards for contextual validation. We will then examine the clinical and scientific applications of DNA microarray technology with an emphasis on important limitations and implications for cardiovascular medicine.
Effects of S-Nitrosation and Cross-Linking of Hemoglobin on Hypoxic Pulmonary Vasoconstriction in Isolated Rat Lungs
Authors: Deem Steven , Kim Joung-Uk , Manjula Belur N. , Acharya A. Seetharama , Kerr Mark E. , Patel Rakesh P. , Gladwin Mark T. , Swenson Erik R.
Published: October 2002

Free hemoglobin (Hb) and red blood cells augment hypoxic pulmonary vasoconstriction (HPV) by scavenging nitric oxide (NO). S-nitrosation of Hb (SNO-Hb) may confer vasodilatory properties by allowing release of NO during deoxygenation and/or by interaction with small-molecular weight thiols. Likewise, cross-linking of free Hb may limit its vasoconstrictive effect by preventing abluminal movement of the molecule. We compared the effects of free SNO-Hb and Hb intramolecularly cross-linked at the β-cysteine 93 residue [Bis(maleidophenyl)-polyethylene glycol2000HbA (Bis-Mal-PEGHb)] to those of free oxyHb on pulmonary artery pressure (PAP), HPV, and exhaled NO (eNO) in isolated, perfused rat lungs. Ventilation of lungs with anoxic gas for 5 minutes reduced perfusate P
o
2
to 11±1.0 Torr. Addition of SNO-Hb or Bis-Mal-PEGHb (100 μmol/L) to buffer perfusate increased normoxic PAP and augmented HPV in similar magnitude as free oxyHb, but had no effect on eNO. Addition of the allosteric modulator inositol hexaphosphate to increase Hb P50 and the thiol glutathione (GSH) to allow removal of NO from Hb via transnitrosation to the perfusate did not reduce augmentation of HPV by SNO-Hb or increase eNO. GSH resulted in an ≈50% reduction in perfusate [
S
-nitrosothiol], in association with an increase in perfusate [metHb]. Free SNO-Hb is a net NO scavenger and pulmonary vasoconstrictor in this model, although thiol-mediated release of NO from SNO-Hb does occur. However, release of NO from SNO-Hb was not influenced by deoxygenation-mediated allosteric changes in Hb across a broad range of oxyHb saturation. Cross-linking of Hb does not limit its pulmonary vasoconstrictor effects.
Adrenomedullin Reduces Endothelial Hyperpermeability
Authors: Hippenstiel Stefan , Witzenrath Martin , Schmeck Bernd , Hocke Andreas , Krisp Mathias , Krüll Matthias , Seybold Joachim , Seeger Werner , Rascher Wolfgang , Schütte Hartwig , Suttorp Norbert
Published: October 2002

Endothelial hyperpermeability induced by inflammatory mediators is a hallmark of sepsis and adult respiratory distress syndrome. Increased levels of the regulatory peptide adrenomedullin (ADM) have been found in patients with systemic inflammatory response. We analyzed the effect of ADM on the permeability of cultured human umbilical vein endothelial cell (HUVEC) and porcine pulmonary artery endothelial cell monolayers. ADM dose-dependently reduced endothelial hyperpermeability induced by hydrogen peroxide (H
2
O
2
), thrombin, and
Escherichia coli
hemolysin. Moreover, ADM pretreatment blocked H
2
O
2
-related edema formation in isolated perfused rabbit lungs and increased cAMP levels in lung perfusate. ADM bound specifically to HUVECs and porcine pulmonary artery endothelial cells and increased cellular cAMP levels. Simultaneous inhibition of cAMP-degrading phosphodiesterase isoenzymes 3 and 4 potentiated ADM-dependent cAMP accumulation and synergistically enhanced ADM-dependent reduction of thrombin-induced hyperpermeability. However, ADM showed no effect on endothelial cGMP content, basal intracellular Ca
2+
levels, or the H
2
O
2
-stimulated, thrombin-stimulated, or
Escherichia coli
hemolysin–stimulated Ca
2+
increase. ADM diminished thrombin- and H
2
O
2
-related myosin light chain phosphorylation as well as stimulus-dependent stress fiber formation and gap formation in HUVECs, suggesting that ADM may stabilize the barrier function by cAMP-dependent relaxation of the microfilament system. These findings identify a new function of ADM and point to ADM as a potential interventional agent for the reduction of vascular leakage in sepsis and adult respiratory distress syndrome.
High-Density Lipoprotein Regulates Calcification of Vascular Cells
Authors: Parhami Farhad , Basseri Benjamin , Hwang Jason , Tintut Yin , Demer Linda L.
Published: October 2002

Accumulating evidence has suggested the protective role of HDL in cardiovascular disease processes. Calcification is a common feature of atherosclerotic lesions and contributes to cardiovascular complications due to the loss of aortic resilience and function. Recent studies have suggested that vascular calcification shares several features with skeletal bone formation at the cellular and molecular levels. These include the presence of osteoblast-like calcifying vascular cells in the artery wall that undergo osteoblastic differentiation and calcification in vitro. We hypothesized that HDL may also protect against vascular calcification by regulating the osteogenic activity of these calcifying vascular cells. When treated with HDL, alkaline phosphatase activity, a marker of osteogenic differentiation of osteoblastic cells, was significantly reduced in those cells. Prolonged treatment with HDL also inhibited calcification of these cells, further supporting the antiosteogenic differentiation property of HDL when applied to vascular cells. Furthermore, HDL inhibited the osteogenic activity that was induced by inflammatory cytokines interleukin (IL)-1β and IL-6 as well as by minimally oxidized LDL. HDL also partially inhibited the IL-6-induced activation of signal transducer and activator of transcription 3 in calcifying vascular cells, suggesting that HDL may inhibit cytokine-induced signal transduction pathways. The inhibitory effects of HDL were mimicked by lipids extracted from HDL but not by HDL-associated apolipoproteins or reconstituted HDL. Furthermore, oxidation of HDL rendered it pro-osteogenic. Taken together, these results suggest that HDL regulates the osteoblastic differentiation and calcification of vascular cells and that vascular calcification may be another target of HDL action in the artery wall.
Hypertension-Linked Decrease in the Expression of Brain γ-Adducin
Authors: Yang Hong , Francis Sharon C. , Sellers Kathleen , DeBarros Mia , Sun Chengwen , Sumners Colin , Ferrario Carlos M. , Katovich Michael J. , Muro Andrés F. , Raizada Mohan K.
Published: October 2002

Gene profiling data coupled with adducin polymorphism studies led us to hypothesize that decreased expression of this cytosolic protein in the brain could be a key event in the central control of hypertension. Thus, our objectives in the present study were to (1) determine which adducin subunit gene demonstrates altered expression in the hypothalamus and brainstem (two cardioregulatory-relevant brain areas) in two genetic strains of hypertensive rats and (2) analyze the role of adducins in neurotransmission at the cellular level. All three adducin subunits (α, β, and γ) were present in the hypothalamus and brainstem of Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. However, only the γ-adducin subunit expression was 40% to 60% lower in the SH rat compared with WKY rat. A similar decrease in γ-adducin expression was observed in the hypothalamus and brainstem of the renin transgenic rat compared with its normotensive control. Losartan treatment of the SH rat failed to normalize γ-adducin gene expression. A hypertension-linked decrease of γ-adducin was confirmed by demonstrating a decrease in γ-adducin expression in hypothalamic/brainstem neuronal cultures from prehypertensive SH rats. Neuronal firing rate was evaluated to analyze the role of this protein in neurotransmission. Perfusion of a γ-adducin–specific antibody caused a 2-fold increase in the neuronal firing rate, an effect similar to that observed with angiotensin II. Finally, we observed that preincubation of neuronal cultures for 8 hours with 100 nmol/L angiotensin II caused a 60% decrease in endogenous γ-adducin and was associated with a 2-fold increase in basal firing rate. These observations support our hypothesis that a decrease in γ-adducin expression in cardioregulatory-relevant brain areas is linked to hypertension possibly by regulating the release of neurotransmitters.
Acidification Prevents Endothelial Cell Apoptosis by Axl Activation
Authors: D’Arcangelo Daniela , Gaetano Carlo , Capogrossi Maurizio C.
Published: October 2002

Prior studies have shown that acidification due to hypercarbia protects endothelial cells from serum deprivation–induced apoptosis. However, the mechanism(s) responsible for the antiapoptotic effect of acidification is still unclear. cDNA array screening was performed on human umbilical vein endothelial cells cultured in a bicarbonate medium equilibrated either with 5% CO
2
(pH 7.4) or with 20% CO
2
(pH 7.0). Tyrosine kinase receptor Axl expression was 3.3-fold higher after 6 hours at pH 7.0 compared with pH 7.4; this modulation was confirmed by reverse transcriptase–polymerase chain reaction (3.0±0.9-fold,
P
<0.03; n=3), Northern blot (3.6±0.1-fold,
P
<0.0003; n=3), and Western blot (10±1.8-fold,
P
<0.004; n=3). In a time-course study, both Northern and Western blot analyses showed that the most marked difference in Axl expression between pH 7.4 and pH 7.0 occurred after 24 to 48 hours. Furthermore, Axl phosphorylation was enhanced at pH 7.0. Axl ligand, the survival factor growth arrest–specific gene 6 product (Gas6), was released into the conditioned medium, and by Western blot analysis, similar amounts of protein were found at pH 7.0 and 7.4. Full-length Axl cDNA overexpression reduced serum deprivation–induced apoptosis by 64.4±11.9% in human umbilical vein endothelial cells cultured at pH 7.4 compared with mock-transfected cells (
P
<0.0004). Furthermore, overexpression of either soluble Axl or antisense Gas6 mRNA partially reverted the protective effect of acidification, increasing ≈2.5-fold the number of apoptotic cells at pH 7.0 (control 19.3±2.7%, soluble Axl 48.9±9.7%,
P
<0.001; antisense Gas6 49.3±14.3%,
P
<0.03). In conclusion, Gas6/Axl signaling may play an important role in endothelial cell survival during acidification. The full text of this article is available at http://www.circresaha.org.
Carbon Monoxide Dilates Cerebral Arterioles by Enhancing the Coupling of Ca
2+
Sparks to Ca
2+
-Activated K
+
Channels
Authors: Jaggar Jonathan H. , Leffler Charles W. , Cheranov Serguei Y. , Tcheranova Dilyara , E Shuyu , Cheng Xiaoyang
Published: October 2002

Carbon monoxide (CO) is generated endogenously by the enzyme heme oxygenase. Although CO is a known vasodilator, cellular signaling mechanisms are poorly understood and are a source of controversy. The goal of the present study was to investigate mechanisms of CO dilation in porcine cerebral arterioles. Data indicate that exogenous or endogenously produced CO is a potent activator of large-conductance Ca
2+
-activated K
+
(K
Ca
) channels and Ca
2+
spark–induced transient K
Ca
currents in arteriole smooth muscle cells. In contrast, CO is a relatively poor activator of Ca
2+
sparks. To understand the apparent discrepancy between potent effects on transient K
Ca
currents and weak effects on Ca
2+
sparks, regulation of the coupling relationship between these events by CO was investigated. CO increased the percentage of Ca
2+
sparks that activated a transient K
Ca
current (ie, the coupling ratio) from ≈62% in the control condition to 100% and elevated the slope of the amplitude correlation between these events ≈2.6-fold, indicating that Ca
2+
sparks induced larger amplitude transient K
Ca
currents in the presence of CO. This signaling pathway for CO is physiologically relevant because ryanodine, a ryanodine-sensitive Ca
2+
release channel blocker that inhibits Ca
2+
sparks, abolished CO dilation of pial arterioles in vivo. Thus, CO dilates cerebral arterioles by priming K
Ca
channels for activation by Ca
2+
sparks. This study presents a novel dilatory signaling pathway for CO in the cerebral circulation and appears to be the first presents of a vasodilator that acts by increasing the effective coupling of Ca
2+
sparks to K
Ca
channels.
Accelerated Atherosclerosis and Calcification in Vein Grafts
Authors: Lardenoye J.H.P. , de Vries M.R. , Löwik C.W.G.M. , Xu Q. , Dhore C.R. , Cleutjens J.P.M. , van Hinsbergh V.W.M. , van Bockel J.H. , Quax P.H.A.
Published: October 2002

Vein grafts fail due to development of intimal hyperplasia and accelerated atherosclerosis. Many murine genetic models in which genes are overexpressed, deleted, or mutated have been introduced recently. Therefore, mouse models are very well suited to dissect the relative contribution of different genes in the development of accelerated atherosclerosis. In the present study, we evaluated whether accelerated atherosclerosis in human vein grafts could be mimicked in hypercholesterolemic APOE*3 Leiden transgenic mice. Venous bypass grafting was performed in the carotid artery in APOE*3 Leiden mice fed either a standard chow diet or a high cholesterol–rich diet for 4 weeks. At several time points (0 hour to 28 days), mice were euthanized and the morphology of the vein grafts was analyzed. In normocholesterolemic mice, vein graft thickening up to 10-fold original thickness, predominantly consisting of α-smooth muscle cell actin–positive cells, was observed after 28 days. In hypercholesterolemic mice, accelerated atherosclerosis with accumulation of lipid-loaded foam cells was observed within 7 days after surgery. This accelerated atherosclerosis progressed in time and resulted in significant increase in vein graft thickening up to 50 times original thickness with foam cell–rich lesions and calcification within 28 days after surgery. The atherosclerotic lesions observed in these murine grafts show high morphological resemblance with the atherosclerotic lesions observed in human vein grafts. This accelerated, diet-dependent induction of atherosclerotic-like lesions in murine vein grafts provides a valuable tool in evaluating the mechanisms of accelerated atherosclerosis and therapeutic interventions of vein graft disease.
Quantitative Assessment of the SR Ca
2+
Leak-Load Relationship
Authors: Shannon Thomas R. , Ginsburg Kenneth S. , Bers Donald M.
Published: October 2002

Increased diastolic SR Ca
2+
leak (J
leak
) could depress contractility in heart failure, but there are conflicting reports regarding the J
leak
magnitude even in normal, intact myocytes. We have developed a novel approach to measure SR Ca
2+
leak in intact, isolated ventricular myocytes. After stimulation, myocytes were exposed to 0 Na
+
, 0 Ca
2+
solution ±1 mmol/L tetracaine (to block resting leak). Total cell [Ca
2+
] does not change under these conditions with Na
+
-Ca
2+
exchange inhibited. Resting [Ca
2+
]
i
declined 25% after tetracaine addition (126±6 versus 94±6 nmol/L;
P
<0.05). At the same time, SR [Ca
2+
] ([Ca
2+
]
SRT
) increased 20% (93±8 versus 108±6 μmol/L). From this Ca
2+
shift, we calculate J
leak
to be 12 μmol/L per second or 30% of the SR diastolic efflux. The remaining 70% is SR pump unidirectional reverse flux (backflux). The sum of these Ca
2+
effluxes is counterbalanced by unidirectional forward Ca
2+
pump flux. J
leak
also increased nonlinearly with [Ca
2+
]
SRT
with a steeper increase at higher load. We conclude that J
leak
is 4 to 15 μmol/L cytosol per second at physiological [Ca
2+
]
SRT
. The data suggest that the leak is steeply [Ca
2+
]
SRT
-dependent, perhaps because of increased [Ca
2+
]
i
sensitivity of the ryanodine receptor at higher [Ca
2+
]
SRT
. Key factors that determine [Ca
2+
]
SRT
in intact ventricular myocytes include (1) the thermodynamically limited Ca
2+
gradient that the SR can develop (which depends on forward flux and backflux through the SR Ca
2+
ATPase) and (2) diastolic SR Ca
2+
leak (ryanodine receptor mediated).
Both Donor and Recipient Origins of Smooth Muscle Cells in Vein Graft Atherosclerotic Lesions
Authors: Hu Yanhua , Mayr Manuel , Metzler Bernhard , Erdel Martin , Davison Fergus , Xu Qingbo
Published: October 2002

Smooth muscle cell (SMC) accumulation in the inner layer of the vessel wall is a key event in the pathogenesis of atherosclerosis in vein grafts, but the origin of the cells in these lesions has yet to be shown. Herein, we use animal models of vein grafts in transgenic mice to clearly identify the sources of SMCs in atherosclerosis. Vena cava segments were isografted to carotid arteries between four types of transgenic mice, including SM-LacZ expressing β-galactosidase (β-gal) in vascular SMCs, SM-LacZ/apoE
−/−
, ROSA26 expressing β-gal in all tissues, and wild-type mice. β-gal–positive cells were observed in neointimal and atherosclerotic lesions of all vein segments grafted between LacZ transgenic and wild-type mice. Double staining for β-gal and cell nuclei revealed that about 40% of SMCs originated from hosts and 60% from the donor vessel. This was confirmed by double labeling of the Y-chromosome and α-actin in the lesions of sex-mismatched vein grafts. The possibility that bone marrow cells were the source of SMCs in grafts was eliminated by the absence of β-gal staining in atherosclerotic lesions of chimeric mice. Furthermore, vein SMCs of SM-LacZ mice did not express β-gal in situ, but did so when these cells appeared in atherosclerotic lesions in vivo, suggesting that hemodynamic forces may be crucial for SMC differentiation. Thus, we provide the first evidence of SMC origins in the atherosclerotic lesions of vein grafts, which will be essential for providing insight into new types of therapy for the disease. The full text of this article is available at http://www.circresaha.org.
Decrease of Proinflammatory Molecules Correlates With Neuroprotective Effect of the Fluorinated Salicylate Triflusal After Postnatal Excitotoxic Damage
Authors: Acarin Laia , González Berta , Castellano Bernardo
Published: October 2002

Background and Purpose—

The fluorinated salicylate triflusal has been shown to have a neuroprotective effect after an excitotoxic lesion to the postnatal brain. In this regard, the aim of this study was to elucidate whether neuroprotection was associated with changes in the expression of proinflammatory molecules such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), or cyclooxygenase-2 (COX-2), well-known mediators of oxidative stress and inflammation, mechanisms underlying secondary damage occurring after excitotoxic/ischemic brain injury.

Methods—

Postnatal day 9 rats received an intracortical injection of
N
-methyl-
d
-aspartate followed by oral administration of triflusal (30 mg/kg) 8 hours later. Ten or 24 hours after lesion, animals were killed, and brain sections processed for the immunohistochemical demonstration of IL-1β, TNF-α, iNOS, and COX-2.

Results—

Besides a reduction in the neurodegenerative area, triflusal strongly decreased iNOS immunolabeling at both survival times analyzed, attenuating iNOS immunoreactivity in astroglial cells and infiltrated neutrophils. Additionally, a moderate reduction in COX-2, IL-1β, and TNF-α was observed. Triflusal decreased neuronal and microglial COX-2 expression at 10 and 24 hours after lesion and microglial and astroglial expression of IL-1β and TNF-α at 24 hours after lesion. TNF-α expression in neuronal cells at 10 hours after lesion was, however, maintained.

Conclusions—

This study suggests that triflusal neuroprotection is associated with a decrease of iNOS and other inflammatory mediators and therefore may constitute a good therapeutic agent in pathological situations in which regulation of inflammatory genes constitutes a relevant step in the outcome of the neurodegenerative event.
Prereperfusion Saline Infusion Into Ischemic Territory Reduces Inflammatory Injury After Transient Middle Cerebral Artery Occlusion in Rats
Authors: Ding Yuchuan , Li Jie , Rafols Josè A. , Phillis John W. , Diaz Fernando G.
Published: October 2002

Background and Purpose—

In ischemic stroke, the ischemic crisis activates a cascade of events that are potentiated by reperfusion, eventually leading to cell death. The chief aim in this study was to investigate whether our new experimental model for stroke therapy, flushing the ischemic territory with saline before reperfusion, could minimize this damage by (1) reducing the inflammatory reaction and (2) improving regional microcirculation.

Methods—

Stroke in Sprague-Dawley rats (n=39) was induced by a 2-hour middle cerebral artery occlusion with the use of a novel intraluminal hollow filament. Before 48-hour reperfusion, 20 of the ischemic rats received 7 mL isotonic saline at 23°C or 37°C infused into the ischemic area through the filament. Regional cerebral blood flow in cortex supplied by the right middle cerebral artery was measured by laser-Doppler flowmetry during ischemia and reperfusion. Leukocyte infiltration, microvascular plugging, and infarct volume were compared with the use of hematoxylin and eosin staining. Expression of intercellular adhesion molecule 1 (ICAM-1) was determined by immunocytochemistry. Neurological deficits were evaluated.

Results—

After the prereperfusion infusion of saline, significantly (
P
<0.001) improved cerebral blood flow (105±12% of baseline) was obtained up to 48 hours after reperfusion, compared with 45±7% at 24 hours and 25±3% at 48 hours after reperfusion without local saline infusion. Significant (
P
<0.001) reductions in leukocyte infiltration (61%), vascular plugging (45%), infarct volume (approximately 65%), and neurological deficits were also produced. ICAM-1 expression in the infarct region was significantly (
P
<0.05) minimized by 37%.

Conclusions—

The reduced brain infarct and neurological deficits may be attributed to adequate reperfusion and ameliorated inflammation induced by local prereperfusion infusion.
Mutations in the Hemochromatosis Gene (
HFE
) and Stroke
Authors: Njajou Omer T. , Hollander Monika , Koudstaal Peter J. , Hofman Albert , Witteman Jacqueline C.M. , Breteler Monique M.B. , van Duijn Cornelia M.
Published: October 2002

Background and Purpose—

Increased serum iron is found to be a risk factor for stroke. Carriers of
HFE
C282Y and H63D mutations have elevated serum iron levels and may have an increased risk for stroke. We studied the association between
HFE
gene mutations, carotid atherosclerosis, and stroke.

Methods—

We compared the frequency of the
HFE
C282Y and H63D gene mutations in 202 prevalent and incident cases of stroke with that of 2730 controls from a population-based study, the Rotterdam Study. The influence of
HFE
mutations on the relationship between hypertension, smoking, and stroke was studied by use of a logistic regression model. In the analyses of hypertension, we used noncarriers and nonhypertensives as reference; in the analysis of smoking, we used noncarriers and those who never smoked as the reference group. Furthermore, we studied the mean intima-media thickness of the common carotid artery in relation to hypertension, smoking, and the
HFE
genotype in subjects without stroke.

Results—

The percentage of both C282Y and H63D carriers in cases (43.7%, n=87) did not differ significantly (
P
=0.09) from that of controls (37.6%, n=986). The odds ratio for stroke for
HFE
carriers who also suffered from hypertension was 3.0 (95% CI, 1.9 to 4.6), and for
HFE
carriers who were also smokers, the odds ratio for stroke was 2.6 (95% CI, 1.4 to 5.0). The mean±SD intima-media thickness of the carotid artery was 0.77±0.14 mm for noncarriers without a history of hypertension or smoking compared with 0.81±0.17 mm for
HFE
carriers who smoked (
P
<0.004) and 0.84±0.20 mm for
HFE
carriers who were hypertensive (
P
<0.001).

Conclusions—

Mutations in the
HFE
gene were not significantly related to stroke or atherosclerosis in the carotid artery. The
HFE
gene may modify the relationship between smoking and stroke.
Personality and Vulnerability to Depression in Stroke Patients
Authors: Aben Ivo , Denollet Johan , Lousberg Richel , Verhey Frans , Wojciechowski Franz , Honig Adriaan
Published: October 2002

Background and Purpose—

Depression is a frequent sequela of stroke that negatively interferes with rehabilitation outcome. Personality traits have been neglected as potential vulnerability factors for poststroke depression (PSD). In a 1-year prospective study, the influence of the 5 main personality traits (ie, neuroticism, extraversion, openness, agreeableness, and conscientiousness) on the development of PSD was studied.

Methods—

One month after stroke, 190 consecutive patients with a first-ever supratentorial infarct were asked to complete a personality inventory, the NEO-Five Factor Inventory, which is based on the Five Factor Model of personality. Depressive symptoms were assessed 1, 3, 6, 9, and 12 months after stroke with 3 self-rating questionnaires as screening instruments for depression. PSD was diagnosed as major or minor depression through the use of the Structured Clinical Interview from the
Diagnostic and Statistical Manual of Mental Disorders
.

Results—

The 1-year cumulative incidence of depression was 38.7%. Cox regression analysis showed that patients with high neuroticism scores had a 4.6-times-higher risk of developing PSD than patients with low neuroticism scores (
P
=0.001) regardless of lesion location. Level of handicap was the only other factor that showed an independent effect on the occurrence of PSD.

Conclusions—

Neuroticism is an important predictor of PSD, a finding that emphasizes the need to take personality into account as a potential vulnerability factor for depression in stroke patients. Research on PSD should aim at delineating the interplay between neurological and psychological factors in the development of PSD.
Comparison of Risk Factors in Patients With Transient and Prolonged Eye and Brain Ischemic Syndromes
Authors: Mead Gillian E. , Lewis Stephanie C. , Wardlaw Joanna M. , Dennis Martin S.
Published: October 2002

Background and Purpose—

Patients with ischemic stroke, cerebral transient ischemic attacks (TIAs), retinal artery occlusion (RAO), and amaurosis fugax are thought to have similar risk factors and underlying vascular disease. However, if risk factors are different in patients with eye compared with brain symptoms and in those whose symptoms last <24 hours (transient) compared with those lasting >24 hours (prolonged), more focused prevention strategies are possible in the future.

Methods—

All patients with ischemic stroke, cerebral TIA, RAO, and amaurosis fugax presenting to our hospital from 1994 to 1999 were examined by a stroke physician. Risk factors were documented, and patients underwent carotid Doppler ultrasound.

Results—

We registered 1491 patients with ischemic stroke, 580 with cerebral TIA, 79 with RAO, and 138 with amaurosis fugax. Atrial fibrillation was more common in brain than eye events, whether prolonged [ischemic stroke versus RAO: odds ratio (OR), 3.6; 95% confidence interval (CI), 1.1 to 12] or transient (cerebral TIA versus amaurosis fugax: OR, 2.9; 95% CI, 0.7 to 13), and more common in prolonged than transient events, whether brain (stroke versus cerebral TIA: OR, 3.3; 95% CI, 2.1 to 5.1) or eye (RAO versus amaurosis fugax: OR, 2.7; 95% CI, 0.4 to 16). Severe ipsilateral carotid disease was less common in brain than eye events, whether prolonged (ischemic stroke versus RAO: OR, 0.6; 95% CI, 0.3 to 1.0) or transient (cerebral TIA versus amaurosis fugax: OR, 0.4; 95% CI, 0.2 to 0.6).

Conclusions—

These data suggest that there are pathogenetic differences between transient and permanent eye and brain ischemic syndromes. Improved understanding of these mechanisms could lead to more effective stroke prevention.
Prognostic Relevance of Early Serial C-Reactive Protein Measurements After First Ischemic Stroke
Authors: Winbeck Kerstin , Poppert Holger , Etgen Thorleif , Conrad Bastian , Sander Dirk
Published: October 2002

Background and Purpose—Recent studies described an association between elevated levels of C-reactive protein (CRP) and outcome after ischemic stroke. We investigated the impact of early serial CRP measurements in hyperacute ischemic stroke on long-term outcome.

Methods—One hundred twenty-seven consecutive patients without thrombolysis with a first ischemic stroke no more than 12 hours after symptom onset were examined. Serial CRP measurements were done at admission (CRP 1), within 24 hours (CRP 2), and within 48 hours (CRP 3) after symptom onset. In addition to several cerebrovascular risk factors, the 1-year outcome and the lesion volumes of initial diffusion-weighted images were determined.

Results—The CRP concentration increased significantly during the first 48 hours after symptom onset (CRP 1, 0.86 mg/dL [95% CI, 0.69 to 1.02]; CRP 2, 1.22 mg/dL [95% CI, 0.88 to 1.55]; CRP 3, 1.75 mg/dL [95% CI, 1.25 to 2.25];P=0.003). Multiple logistic regression analysis identified Barthel Index score at admission and CRP 2 and 3 as independent predictors of an unfavorable outcome. Kaplan-Meier analysis revealed a significantly higher rate of end point events (adjusted odds ratio, 3.9 [95% CI, 1.4 to 10.7];P=0.008) only in patients with elevated CRP 2 concentrations.

Conclusions—The CRP level measured within 12 hours after symptom onset of an acute ischemic stroke is not independently related to long-term prognosis. In contrast, a CRP increase between 12 and 24 hours after symptom onset predicts an unfavorable outcome and is associated with an increased incidence of cerebrovascular and cardiovascular events.
Safety of Tissue Plasminogen Activator for Acute Stroke in Menstruating Women
Authors: Wein Theodore H. , Hickenbottom Susan L. , Morgenstern Lewis B. , Demchuk Andrew M. , Grotta James C.
Published: October 2002

Background—

Menses is a theoretical contraindication to intravenous tissue plasminogen activator (tPA) treatment. We sought to establish the safety of intravenous tPA in the treatment of acute ischemic stroke in women who are actively menstruating.

Summary of Report—

We provide a case report and review of the National Institute of Neurological Disorders and Stroke (NINDS) database for women coded as actively menstruating. Nine subjects were coded as actively menstruating in the NINDS trial (4 placebo and 5 in the treatment). One subject in the treatment group who had a 1-year history of dysfunctional uterine bleeding required emergent uterine artery ligation. We also report a case of a woman requiring transfusion after intravenous tPA administration for acute ischemic stroke.

Conclusions—

Intravenous tPA may be administered relatively safely in women who are menstruating and should be used with caution in women with a history of dysfunctional uterine bleeding. Potential patients should be advised that they might require transfusion for increased menstrual flow.
Effect of Intravenous Thrombolysis on MRI Parameters and Functional Outcome in Acute Stroke <6 Hours
Authors: Röther J. , Schellinger P.D. , Gass A. , Siebler M. , Villringer A. , Fiebach J.B. , Fiehler J. , Jansen O. , Kucinski T. , Schoder V. , Szabo K. , Junge-Hülsing G.J. , Hennerici M. , Zeumer H. , Sartor K. , Weiller C. , Hacke W.
Published: October 2002

Background and Purpose—

The goals of this study were to examine MRI baseline characteristics of patients with acute ischemic stroke (AIS) and to study the influence of intravenous tissue plasminogen activator (tPA) on MR parameters and functional outcome using a multicenter approach.

Methods—

In this open-label, nonrandomized study of AIS patients with suspected anterior circulation stroke, subjects received a multiparametric stroke MRI protocol (diffusion- and perfusion-weighted imaging and MR angiography) within 6 hours after symptom onset and on follow-up. Patients were treated either with tPA (thrombolysis group) or conservatively (no thrombolysis group). Functional outcome was assessed on day 90 (modified Rankin Score; mRS).

Results—

We enrolled 139 AIS patients (no thrombolysis group, n=63; thrombolysis group, n=76). Patients treated with tPA were more severely affected (National Institutes of Health Stroke Scale score, 10 versus 13;
P
=0.002). Recanalization rates were higher in the thrombolysis group (Thrombolysis in Myocardial Infarction criteria 1 through 3 on day 1; 66.2% versus 32.7%;
P
<0.001). Proximal vessel occlusions resulted in larger infarct volumes and worse outcome (
P
=0.02). Thrombolysis was associated with a better outcome regardless of the time point of tPA treatment (≤3 hours or 3 to 6 hours) (univariate analysis: mRS ≤2,
P
=0.017; mRS ≤1,
P
=0.023). Age (
P
=0.003), thrombolytic therapy at 0 to 6 hours (
P
=0.01), recanalization (
P
=0.016), lesion volume on day 7 (
P
=0.001), and initial National Institutes of Health Stroke Scale score (
P
=0.001) affected functional outcome (mRS on day 90) positively (multivariate analysis). The time point of tPA therapy affected the recanalization rate (
P
=0.024) but not final infarct volume.

Conclusions—

In this pilot study, tPA therapy had a beneficial effect on vessel recanalization and functional outcome. Multiparametric MRI delineates tissue at risk of infarction in AIS patients, which may be helpful for the selection of patients for tPA therapy. tPA therapy appeared safe and effective beyond a 3-hour time window. This study delivers the rationale for a randomized, MR-based tPA trial.
Identifying Patients With Symptomatic Carotid Artery Disease at High and Low Risk of Severe Myocardial Infarction and Cardiac Death
Authors: Gates Peter C. , Eliasziw Michael , Algra Ale , Barnett Henry J.M. , Gunton Ramsay W.
Published: October 2002

Background and Purpose—

The extent of cardiac investigation required in patients with coexistent symptomatic carotid and cardiac disease is unsettled. This study compared the outlook for patients symptomatic from carotid stenosis with and without a history of symptomatic ischemic heart disease (IHD).

Methods—

The risk of combined outcome of severe myocardial infarction and cardiac death was evaluated in patients from the North American Symptomatic Carotid Endarterectomy Trial.

Results—

A total of 1124 patients had a history of symptomatic IHD and 1691 did not. The median age was 66 years; 70% were male. With history of IHD at entry, the 5-year risk of combined outcome of severe myocardial infarction and cardiac death was 16.5% (95% CI, 13.9 to 19.0). Without history at entry, risk was 6.7% (95% CI, 5.1 to 8.3). Risk of unheralded severe MI and cardiac death was only 3.3%. One hundred ninety-four patients had ≥4 of the following risk factors: age ≥75 years, history of diabetes, history of hypertension, smoking in past year, left ventricular hypertrophy on ECG, myocardial infarction on ECG, or creatinine >115 μmol/L. The 5-year risk of severe myocardial infarction or cardiac death increased to 33.9% for patients with ≥4 risk factors and a history of IHD and to 23.5% for those without history of IHD.

Conclusions—

Most patients with symptomatic carotid stenosis without symptomatic IHD had a low risk of severe myocardial infarction and cardiac death. With many risk factors, these patients had a risk high enough to warrant cardiac investigations.
Detection of Carotid Artery Stenosis by In Vivo Duplex Ultrasound
Authors: Schulte-Altedorneburg Gernot , Droste Dirk W. , Felszeghy Szabolcs , Csiba László , Popa Vasile , Hegedüs Katalin , Kollár József , Módis László , Ringelstein E. Bernd
Published: October 2002

Background and Purpose—

The correct detection and quantification of carotid artery disease are of decisive impact on patient prognosis and adequate treatment. In this study, we evaluated the ability of ultrasonography to detect and to grade carotid artery stenosis through a comparison of the in vivo ultrasound findings with the planimetric analysis of the corresponding postmortem specimens.

Methods—

Shortly before their death, 59 critically ill neurological patients (mean age, 70 years) were prospectively examined by extracranial and intracranial Doppler sonography and color-coded duplex ultrasound. Carotid stenosis was classified by hemodynamic and morphological ultrasound criteria. Carotid specimens were removed in toto during autopsy. Under standardized conditions, specimens were redistended, sectioned, and histologically processed. Computerized planimetric measurements of the arteries were carried out and compared with the ultrasound findings. Correlation of the ultrasound and postmortem planimetric findings was available in 93 carotid bifurcations.

Results—

Through both techniques, 46 carotid arteries were found to be normal. Steno-occlusive carotid lesions ranged from 8.5% to 100% lumen reduction. Overall,
r
=0.96 and adjusted
R
2
=0.90. For the steno-occlusive carotid lesions,
r
=0.91.

Conclusions—

Extracranial and intracranial Doppler and color-coded duplex ultrasound permits reliable detection and quantification of carotid artery stenoses and occlusions even under difficult examination conditions in critically ill patients.