(Circulation. 1999;100:II-335.)
© 1999 American Heart Association, Inc.
Myocardial Protection and Vascular Biology |
Recombinant Gene Transfer of Endothelial Nitric Oxide Synthase Augments Coronary Artery Relaxations During Hypoxia
From the Cardiac Surgical Research Center (D.G.C., H.V.S.), Department of Endocrinology (T.O.), and the Section of Cardiovascular Surgery (D.G.C., H.V.S.), Mayo Clinic and Mayo Foundation, Rochester, Minn; and the Department of Medicine (V.J.P.), The Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis.
Correspondence to Hartzell V. Schaff, MD, Section of Cardiovascular Surgery, Mayo Clinic and Mayo Foundation, 200 First St SW, Rochester, MN 55905. E-mail schaff{at}mayo.edu
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Abstract |
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Background—Coronary arteries respond to hypoxia with transient relaxations, which increases coronary blood flow, in part, by release of nitric oxide. We hypothesized that increased expression of nitric oxide synthase might further augment blood vessel relaxation during hypoxia. The present study examined the effect of adenovirus-mediated transfer of bovine endothelial nitric oxide synthase (eNOS) on hypoxia-induced transient relaxations in canine coronary arteries.
Methods and Results—Paired segments of coronary arteries
were exposed to vehicle (phosphate-buffered saline with albumin)
or an adenovirus encoding either E coli
ß-galactosidase (Ad.CMVLacZ, viral control; 1010 pfu/mL)
or eNOS (Ad.CMVeNOS; 1010 pfu/mL) for 2 hours at 37°C.
Immunohistochemistry with a monoclonal antibody specific for eNOS
documented both endothelial and adventitial expression
in Ad.CMVeNOS arteries, whereas vehicle and viral controls demonstrated
only constitutive expression. Levels of cGMP were increased 5-fold in
Ad.CMVeNOS arteries compared with controls. In arteries exposed to
Ad.CMVeNOS, maximum contraction to prostaglandin
F2
was reduced compared with viral controls, and this
effect was eliminated by pretreatment with a competitive
inhibitor of eNOS
(NG-monomethyl-L-arginine,
10-3 mol/L). Hypoxia-induced transient relaxation
(95% N2-5% CO2) in Ad.CMVeNOS arteries
(45.2±8.8%, n=6) was augmented compared with vehicle (26.3±6.0%) or
viral (27.2±7.1%) controls.
Conclusions—Adenovirus-mediated gene transfer of nitric oxide synthase reduces receptor-dependent contractions and augments hypoxia-induced relaxations in canine coronary arteries; this method of augmentation of NO production might be advantageous for reduction of coronary artery vasospasm.
Key Words: arteries • genes • genetics • nitric oxide • hypoxia • ß-galactosidase • ischemia
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Introduction |
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Coronary arteries respond to hypoxic insult with a transient relaxation followed by contraction. This transient relaxation may be a homeostatic mechanism to preserve or augment coronary perfusion. Previous investigations have documented endothelial release of both prostacyclin and nitric oxide during hypoxia.1 2 3 4 Release of these vasoactive substances may explain, in part, the initial transient relaxation of isolated vessels during hypoxia. However, accumulation of cGMP, the common effector of nitric oxide, is impaired during hypoxia at the level of the membrane receptor, G-protein, or nitric oxide synthase.5 6 7 Therefore, augmentation of nitric oxide production, as with gene transfer of nitric oxide synthase, may not produce a biological effect during hypoxia.
Continued hypoxia induces coronary artery contractions, the mechanism of which remains undefined, although an endothelium-derived contracting factor has been postulated.8 Vessels mechanically denuded of endothelium produce only a mild relaxation on exposure to hypoxia. The addition of an endothelial source to the organ bath is associated with a return of hypoxia-induced contractions, which suggests a diffusible factor. However, all presently identified endothelium-dependent contracting factors have now been excluded as mediators. The ability to reverse or counter the actions of this contracting factor by augmentation of nitric oxide production has not been reported to date, but this property might be advantageous in reducing coronary artery vasospasm.
We have previously demonstrated a role of nitric oxide in hypoxic vasoactive responses,9 but the effect of overexpression of NOS is not known. Accordingly, we designed experiments to evaluate adenovirus-mediated gene transfer of bovine endothelial nitric oxide synthase (eNOS) to canine coronary arteries and the subsequent response to hypoxia.
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Methods |
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Humane care was provided in compliance with the "Principles of Laboratory Animal Care" formulated by the National Society for Medical Research and the Guide for the Care and Use of Laboratory Animals prepared by the Institute of Laboratory Animal Resources and published by the National Institutes of Health (NIH Publication No. 85-23, revised 1985). Procedures and handling of tissues exposed to recombinant adenovirus were approved by the Institutional Biosafety Committee of the Mayo Foundation in compliance with Guidelines for Research Involving Recombinant DNA Molecules published by the National Institutes of Health (NIH Publication No. 59FR34496, amended 1995).
Gene Transfer
Coronary arteries were obtained from purpose-bred,
heartworm-free,10 adult canines and divided into 3-
to 4-mm segments; great care was used to ensure that segments were
similar in length in paired arteries. Arteries were exposed to vehicle
(phosphate-buffered saline with albumin [PBSA]) or an
adenovirus encoding E coli ß-galactosidase (Ad.CMVLacZ,
1010 pfu/mL) or eNOS (Ad.CMVeNOS,
1010 pfu/mL) ex vivo for 2 hours at 37°C as
previously described.11 The effect of gene transfer
was evaluated after 24 hours of incubation in a 5%
CO2 incubator (Forma Scientific Inc).
Histology
Vessels were flash-frozen (-70°C), sectioned, and immersed in
acetone (4°C) and 1% paraformaldehyde-EDTA. Goat
serum (5%)–PBS–Tween 20 was used to bind nonspecific protein sites.
An eNOS monoclonal antibody (5 µg/mL; 1:50 dilution; 60 minutes;
Transduction Laboratory) incubation was followed by biotinylated rabbit
anti-mouse F(ab')2 (1:300; 20 minutes) secondary antibody and
peroxidase-conjugated streptavidin (1:300, 20 minutes).
Immunoreactivity of eNOS was documented by 3-amino-9-ethylcarbazole and
hematoxylin counterstaining.
In Vitro Studies
Coronary arteries were then mounted in organ chambers
containing crystalloid solution (pH 7.4, 37°C) aerated with 95%
O2-5% CO2. The modified
Krebs’ solution was of the following composition (mmol/L): NaCl 118.3,
KCl 4.7, MgSO4 1.2,
KH2PO4 1.2,
CaCl2 2.5, NaHCO3 25, and
glucose 11.1. The segments were suspended between 2 stainless-steel
clips connected to a strain gauge for the measurement of isometric
force (Statham UC2, Gould Inc). After confirming the presence of
endothelium, we allowed the segments to equilibrate for
30 minutes with indomethacin
(10-5 mol/L) to block endogenous
cyclooxygenase activity, because hypoxia
releases prostacyclin. Hypoxia was produced by aeration with a
95% N2-5% CO2
mixture.
cGMP Assay
Separate coronary rings were incubated in
1-methyl-3-isobutylxanthine (IBMX, 10-3 mol/L)
for 30 minutes at 37°C. The vessels were flash-frozen in liquid
nitrogen, homogenized in 6% trichloroacetic acid, and
centrifuged at 10 000g. Supernatant fractions were
extracted with diethylether and acetylated, and cGMP was
quantified by radioimmunoassay. Protein was determined by the method of
Lowry12 and the results expressed as picograms per
milligram protein.
Drugs
KCl, prostaglandin F2,
indomethacin, and
NG-monomethyl-L-arginine
(L-NMMA) were obtained from Sigma Chemical Co. All drugs were
prepared in double-deionized water except for
indomethacin, which was dissolved in
Na2CO3
(10-5 mol/L). The final concentration of sodium
carbonate in the organ bath previously has been shown not to alter
vascular responses.13
Statistical Analysis
Results are expressed as mean±SEM. In all experiments, n
indicates the number of canine coronary arteries examined. Only
paired arteries were used in the present series of experiments.
Statistical evaluation of data between 2 paired observations utilized
Student’s t test for equal variance. Two-tailed ANOVA with
post hoc Newman-Keuls was performed on the dose-response curves to
prostaglandin F2. Values were
considered to be statistically significant when P<0.05.
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Results |
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Coronary arteries were immunostained with a monoclonal antibody specific for eNOS. Arteries exposed to either dilution vehicle (PBSA) or control recombinant adenovirus (Ad.CMVLacZ) demonstrated constitutive expression only of eNOS within the endothelium (Figures 1A
and 1B). In contrast, Ad.CMVeNOS
arteries demonstrated high-level expression within the
endothelium, but de novo adventitial expression also
was present (Figure 1C).
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In Vitro Studies
No significant difference was noted in the tension generated to a
maximal concentration of KCl (80 mmol/L). Coronary
arteries exposed to vehicle (PBSA) and viral (Ad.CMVLacZ) controls
generated similar tensions with KCl addition (11.9±0.8 versus
11.8±0.6 g, respectively; n=6; P=0.66). Similar responses
were noted in Ad.CMVeNOS arteries (10.6±0.7 g; P=0.44
versus PBSA, P=0.25 versus Ad.CMVLacZ).
In contrast, when a receptor-dependent contracting agent was used,
significant differences were noted after recombinant transfer of eNOS
(Figure 2). Prostaglandin
F2 generated a maximum tension of 4.3±0.6 g
in PBSA and 4.7±0.7 g in Ad.CMVLacZ arteries (n=6; P=0.98).
A significant reduction in maximum force generated with
prostaglandin F2 was noted in
Ad.CMVeNOS arteries (2.7±0.5 g) when compared with viral
(P=0.05 versus Ad.CMVLacZ) but not vehicle controls
(P=0.07 versus PBSA).
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We were careful to ensure that paired arterial rings were
the same length; greater length could correlate with greater smooth
muscle mass and, subsequent, greater contraction. To guard against this
variable, the maximum tensions generated to
prostaglandin F2 were also
normalized to the KCl contractions. Prostaglandin
F2 generated a normalized tension of
36.1±4.5% KCl in PBSA and 39.6±5.9% KCl in Ad.CMVLacZ arteries
(n=6, P=0.89). A significant reduction in maximum
force was again noted in Ad.CMVeNOS arteries (26.2±4.8% KCl) when
compared with viral (P=0.05 versus Ad.CMVLacZ) and now also
with vehicle controls (P=0.03 versus PBSA). This contraction
differential could be eliminated by pretreatment with large
concentrations of L-NMMA (10-3 mol/L), a
competitive inhibitor of nitric oxide synthase. After
pretreatment with L-NMMA, all groups contracted similarly to
prostaglandin F2 (PBSA 60.3±8.1%
KCl versus Ad.CMVLacZ 58.8±19.9% KCl versus Ad.CMVeNOS
49.1±10.6% KCl).
Hypoxia
Hypoxia was generated in the organ chambers by changing
the gas mixture from 95% O2-5%
CO2 to aeration with 95%
N2-5% CO2. The composition
of the buffered crystalloid solution at various times is noted in the
Table 1. Coronary arteries
were contracted with a submaximal concentration of
prostaglandin F2
(10-6 mol/L), thus permitting either relaxation
or contraction. On switching to the hypoxic gas mixture, all vessels
maximally relaxed within 5 minutes (Figure 3). Vehicle (PBSA; 26.3±6.0% baseline;
n=6) and virus (Ad.CMVLacZ; 27.2±7.1% baseline) controls had
similar hypoxia-induced relaxations (P=0.46). A
significant augmentation of hypoxia-induced relaxations was
noted in Ad.CMVeNOS arteries (45.2±8.8% baseline;
P=0.01 versus PBSA, P=0.03 versus
Ad.CMVLacZ).
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After the transient relaxations, sustained contractions were noted in all control and 60% of the Ad.CMVeNOS vessels. No significant difference existed in PBSA (128.6±23.4% contraction), Ad.CMVLacZ (116.8±22.1%, P=0.41 versus PBSA), and Ad.CMVeNOS (127.0±47.9%, P=0.70 versus PBSA, P=0.74 versus Ad.CMVLacZ) arteries with regard to amplitude of hypoxia-induced contractions.
cGMP Levels
To further confirm augmented nitric oxide production in
Ad.CMVeNOS arteries and evaluate the release during hypoxia,
basal and hypoxic levels of cGMP were measured (Figure 4). Basal cGMP was 571.6±138.5 pg/mg of
protein in PBSA (n=5) and 499.2±236.8 pg/mg in Ad.CMVLacZ
(P=0.73 versus PBSA) coronary arteries. A nearly
5-fold increase was seen in basal cGMP level in Ad.CMVeNOS
(2441.2±1309.1 pg/mg; P=0.21 versus PBSA, P=0.14
versus Ad.CMVLacZ), although this did not reach statistical
significance. After 2.5 minutes of hypoxia, vessels treated
with PBSA (760.8±155.2 pg/g) and Ad.CMVLacZ (626.8±243.1 pg/mg)
produced significantly less cGMP than vessels exposed to Ad.CMVeNOS
(1700.0±490.7 pg/mg, P=0.05 versus PBSA, P=0.03
versus Ad.CMVLacZ). If hypoxia was continued for 5 minutes,
similar results were obtained; PBSA (499.2±177.4 pg/g) and Ad.CMVLacZ
(522.2±184.0 pg/mg) had lower cGMP levels than Ad.CMVeNOS
(2048.2±889.0 pg/mg; P=0.11 versus PBSA, P=0.13
versus Ad.CMVLacZ) arteries, although this did not reach statistical
significance.
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Discussion |
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The present study demonstrates the sequelae of eNOS overexpression in coronary arteries during hypoxia. Overexpression of eNOS in canine coronary arteries significantly augmented relaxations during hypoxia, and this was associated with elevated cGMP levels throughout the early period of hypoxia. However, overexpression of eNOS did not alter the amplitude of sustained contractions during continued hypoxia.
Complementary techniques confirmed overexpression of nitric oxide synthase after adenovirus-mediated recombinant gene transfer. A monoclonal antibody specific for constitutive eNOS demonstrated that the enzyme was present in larger amounts in vessels exposed to Ad.CMVeNOS compared with controls. In addition, marked expression of eNOS was noted in the adventitia of these vessels. The affinity of adventitial fibroblasts for adenovirus-mediated gene transfer of NOS has previously been described.14
Furthermore, receptor-dependent contractions were reduced in arteries exposed to Ad.CMVeNOS compared with control vessels, and this difference was reversed by pretreatment with L-NMMA, a competitive inhibitor of nitric oxide synthase.15 Finally, basal cGMP levels were elevated in Ad.CMVeNOS arteries compared with controls. The immunohistochemistry together with the specificity of L-NMMA reversal and basal cGMP levels imply the overexpression of functional nitric oxide synthase in Ad.CMVeNOS coronary arteries. This compilation of findings is similar to previous studies from our laboratory11 16 17 18 19 and from others14 20 that show increased NO release after adenovirus-mediated gene transfer of eNOS.
After confirmation of augmented and functional nitric oxide synthase in vessels exposed to Ad.CMVeNOS, the vasoactivity of these vessels was evaluated. Simply increasing eNOS activity might not augment vasorelaxation during hypoxia. Moderate hypoxia can impair stimulated production of cGMP, and Johns et al21 noted reduced receptor-dependent and -independent stimulated cGMP levels in rabbit pulmonary arteries during hypoxia. However, sodium nitroprusside was still capable of increasing cGMP levels during hypoxia, which suggests that the site at which hypoxia blocked stimulated cGMP production was proximal to activation of soluble guanylate cyclase.
However, in contrast, augmented basal cGMP levels with recombinant NOS overexpression were noted in the present study. No significant attenuation of these basal levels was noted during 5 minutes of hypoxia, the time period that correlated with vasorelaxation. These augmented basal cGMP levels were associated with augmented hypoxic vasoactivity; hypoxia-induced transient relaxations were increased 2-fold in Ad.CMVeNOS arteries. Although a role for nitric oxide in hypoxic vasoactive responses has previously been demonstrated,9 the present studies confirm the utility of eNOS gene transfer to augment responses under hypoxic conditions.
In addition, the present study attempted to inhibit the actions of the contracting factor by overexpression of eNOS. Coronary arteries exposed to Ad.CMVeNOS produced equivalent hypoxia-mediated contractions compared with controls, indicating that eNOS overexpression may not prevent hypoxic-induced vasospasm.
Although augmentation of eNOS expression did not prevent hypoxia-induced vasospasm, increased nitric oxide production might prevent or interrupt the pathophysiology of acute coronary syndromes. Reduced coronary artery blood flow may occur secondary to either a thrombotic occlusion or arterial vasospasm. The inciting, early thrombi are often nonocclusive aggregates of platelets.22 Evidence of arterial vasospasm has been demonstrated pathologically23 and angiographically.24 25 Overexpression of eNOS would be expected to inhibit platelet aggregation and activation while also increasing blood flow by vasodilation, thus preventing tissue hypoxia.
In addition to the potentiation of coronary hypoxia-induced relaxations demonstrated in this study, gene therapy with eNOS augments nitric oxide release from human saphenous vein11 and porcine coronary arteries,19 inhibits intimal hyperplasia in rabbit arteries,20 and augments relaxation16 and inhibits contractions17 of human radial arteries. Despite these potential benefits, concerns still exist regarding the clinical use of eNOS-based gene therapy.
Augmentation of nitric oxide by recombinant gene transfer of eNOS, although unproven to date, would be expected to increase the potent metabolite of nitric oxide, peroxynitrite. Peroxynitrite is capable of lipoprotein oxidation and tyrosine nitration26 27 ; these effects may be cytotoxic at high concentrations.28 The reactive oxidant may arrest sodium ion transport and cause myocardial injury.29 30 In addition to the cytotoxic effects that eNOS overexpression may cause, difficulty with clinical use of the present adenoviral vectors remains. Current vectors may not be applicable to humans because of inadequate safeguards and the potential for immunological response to the virus that could negate any beneficial action of gene transfer.31 In conclusion, adenovirus-mediated transfer of nitric oxide synthase reduces receptor-dependent contractions and augments hypoxia-induced relaxations in canine coronary arteries.
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Acknowledgments |
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The present study was supported in part by The Mayo Foundation and was performed during Dr Cable’s tenure as a Clinical Investigator Research Fellow. Dr O’Brien is supported by grant HL-58080 from the National Institutes of Health. We thank Marilyn R. Oeltjen and Sharon A. Guy for technical support.
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Footnotes |
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Guest editor for the present article was James T. Willerson, MD, St Luke’s Episcopal Hospital/Texas Heart Institute, Houston, Tex.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
-
Busse R, Pohl U, Kellner C, Klemm U.
Endothelial cells are involved in the vasodilatory
response to hypoxia. Pflugers Arch. 1983;397:78–80.[Medline]
[Order article via Infotrieve]
-
Jiang C, Collins P. Inhibition of
hypoxia-induced relaxation of rabbit isolated coronary
arteries by
NG-monomethyl-L-arginine
but not glibenclamide. Br J Pharmacol. 1994;111:711–716.[Medline]
[Order article via Infotrieve]
-
Grser T, Rubanyi GM. Different mechanisms of hypoxic
relaxation in canine coronary arteries and rat abdominal
aortas. J Cardiovasc Pharmacol. 1992;12(suppl
20):S117–S119.
-
Blitzer ML, Lee SD, Creager MA.
Endothelium-derived nitric oxide mediates hypoxic
vasodilation of resistance vessels in humans. Am J
Physiol. 1996;271:H1182–H1185.
[Abstract/Free Full Text]
-
Simonet S, Porro de Bailliencourt J, Descombes JJ,
Mennecier P, Laubie M, Verbeuren TJ. Hypoxia causes an
abnormal contractile response in the atherosclerotic rabbit aorta:
implication of reduced nitric oxide and cGMP production.
Circ Res. 1993;72:616–630.
[Abstract/Free Full Text]
-
Phelan MW, Faller DV. Hypoxia decreases
constitutive nitric oxide synthase transcript and protein in cultured
endothelial cells. J Cell Physiol. 1996;167:469–476.[Medline]
[Order article via Infotrieve]
-
Shaul PW, Wells LB, Horning KM. Acute and prolonged
hypoxia attenuate endothelial nitric oxide
production in rat pulmonary arteries by different
mechanisms. J Cardiovasc Pharmacol. 1993;22:819–822.[Medline]
[Order article via Infotrieve]
-
Vahoutte PM, Auch-Schwelk W, Boulanger C, Janssen PA,
Katusic ZS, Komori K, Miller VM, Schini VB, Vidal M. Does endothelin-1
mediate endothelium-dependent contractions during
anoxia? J Cardiovasc Pharmacol. 1989;13(suppl
5):S124–S128.
-
Pearson PJ, Evora PR, Discigil B, Schaff HV.
Hypoxia increases vasodilator release from internal mammary
artery and saphenous vein grafts. Ann Thorac Surg. 1998;65:1220–1225.
[Abstract/Free Full Text]
-
Kaiser L, Tithof PK, Williams JF. Depression of
endothelium-dependent relaxation by filarial parasite
products. Am J Physiol. 1990;259:H648–H652.
[Abstract/Free Full Text]
-
Cable DG, O’Brien T, Schaff HV, Pompili VJ.
Recombinant endothelial nitric oxide
synthase-transduced human saphenous veins: gene therapy to augment
nitric oxide production in bypass conduits.
Circulation. 1997;96(suppl II):173–178.
-
Lowry OH, Rosebraough NF, Farr AL, Randall RJ. Protein
measurement with the folin phenol reagent. J Biol Chem. 1951;193:265–275.
[Free Full Text]
-
Luscher TF, Diederich D, Siebenmann R, Lehmann K, Stulz
P, von Segesser L, Yang ZH, Turina M, Gradel E, Weber E. Difference
between endothelium-dependent relaxation in
arterial and in venous coronary bypass grafts.
N Engl J Med. 1988;319:462–467.[Abstract]
-
Chen AFY, Jiang SW, Crotty TB, Tsutsui M, Smith LA,
O’Brien T, Katusic ZS. Effects of in vivo adventitial expression of
recombinant endothelial nitric oxide synthase gene in
cerebral arteries. Proc Natl Acad Sci U S A. 1997;94:12568–12573.
[Abstract/Free Full Text]
-
Southan GJ, Szabo C. Selective pharmacological
inhibition of distinct nitric oxide synthase isoforms. Biochem
Pharmacol. 1996;51:383–394.[Medline]
[Order article via Infotrieve]
-
Cable DG, Caccitolo JA, Pfeifer EA, Daly RC, Dearani
JA, Mullany CJ, O’Brien T, Orszulak TA, Schaff HV.
Endothelial regulation of vascular contractions in
radial and internal mammary arteries. Ann Thorac Surg. 1999;67:1083–1090.
[Abstract/Free Full Text]
-
Cable DG, Caccitolo JA, Pearson PJ, O’Brien T, Mullany
CJ, Daly RC, Orszulak TA, Schaff HV. New approaches to prevention and
treatment of vasospasm in radial artery bypass grafts.
Circulation. 1998;98(suppl II):II-15—II-22.
-
Mozes G, Kullo I, Mohacsi TG, Cable DG, Spector DJ,
Crotty T, Gloviczki P, Katusic Z, O’Brien T. Nitric oxide synthase
gene transfer improves cholesterol-induced vasomotor
dysfunction in the rabbit aorta.
Atherosclerosis. 1998;141:265–271.[Medline]
[Order article via Infotrieve]
-
Cable DG, O’Brien T, Schwartz RS, Schaff HV, Pompili
VJ. Expression and function of recombinant endothelial
nitric oxide gene in porcine coronary arteries.
Cardiovasc Res. 1997;35:553–559.
[Abstract/Free Full Text]
-
Von der Leyen HE, Gibbons GH, Morishita R, Lewis NP,
Zhang L, Nakajima M, Kaneda Y, Cooke JP, Dzau VJ. Gene therapy
inhibiting neointimal vascular lesion: in vivo transfer of
endothelial cell nitric oxide synthase gene. Proc
Natl Acad Sci U S A. 1995;92:1137–1141.
[Abstract/Free Full Text]
-
Johns RA, Linden JM, Peach MJ.
Endothelium-dependent relaxations and cyclic GMP
accumulation in rabbit pulmonary artery are selectively
impaired by moderate hypoxia. Circ Res. 1989;65:1508–1515.
[Abstract/Free Full Text]
-
Alpert JS. Pathophysiology of acute myocardial
infarction. In: Francis GS, Alpert JS, eds. Modern
Coronary Care. Boston, Mass: Little, Brown and Co;
1990:3–18.
-
Factor SM, Cho S. Smooth muscle contraction bands in
the media of coronary arteries: a postmortem marker of
antemortem coronary spasm? J Am Coll Cardiol. 1985;6:1329–1337.[Abstract]
-
Grollier G, Scanu P, Commeau P, Foucalt JP, Potier JC.
Role of coronary spasm in the genesis of myocardial infarction:
study of a case treated by isosorbide dinitrate in situ then by
transluminal angioplasty. Clin Cardiol. 1985;8:644–648.[Medline]
[Order article via Infotrieve]
-
Conti CR, Mehta JL. Acute myocardial ischemia:
role of atherosclerosis, thrombosis, platelet
activation, coronary vasospasm, and altered
arachidonic acid metabolism.
Circulation. 1987;75(suppl V):84–95.
-
Graham A, Hogg N, Kalyanaraman B, O’Leary V,
Darley-Usmar V, Moncada S. Peroxynitrite modification of low-density
lipoprotein leads to recognition by the macrophage scavenger
receptor. FEBS Lett. 1993;330:181–185.[Medline]
[Order article via Infotrieve]
-
Ischirapoulos H, Zhu L, Chen J, Tsai M, Martin JC,
Smith CD, Beckman JS. Peroxynitrite-mediated tyrosine nitration
catalyzed by superoxide dismutase. Arch Biochem Biophys. 1992;289:431–437.
-
Zhu L, Gunn C, Beckman J. Bactericidal activity of
peroxynitrite. Arch Biochem Biophys. 1992;298:452–457.[Medline]
[Order article via Infotrieve]
-
Mathies G, Sherman MP, Buckberg GD. Role of
L-arginine-nitric oxide pathway in myocardial
reoxygenation injury. Am J Physiol. 1992;262:H616–H620.
[Abstract/Free Full Text]
-
Bauer M, Beckman JS, Bridges R, Matalon S.
Peroxynitrite inhibits sodium transport in rat colonic membrane
vesicles. Biochem Biophys Acta. 1992;1104:84–87.
-
DeYoung MB, Dichek DA. Gene therapy for
restenosis: are we ready? Circ Res. 1998;82:306–313.
[Abstract/Free Full Text]
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