(Stroke. 2000;31:2442.)
© 2000 American Heart Association, Inc.
Original Contributions |
Atorvastatin Upregulates Type III Nitric Oxide Synthase in Thrombocytes, Decreases Platelet Activation, and Protects From Cerebral Ischemia in Normocholesterolemic Mice
From the Klinik III für Innere Medizin, Universität zu Köln (Germany) (U.L., G.N., M. B.); Klinik und Poliklinik für Neurologie, Institut für Experimentelle Neurologie, Charité, Humboldt-Universität zu Berlin (Germany) (K.G., U.D., M.E.); and Cardiovascular Research Center, Massachusetts General Hospital, Harvard University, Charlestown, Mass (P.H.).
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Abstract |
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Background and Purpose—Thrombosis superimposed on atherosclerosis causes approximately two thirds of all brain infarctions. We previously demonstrated that statins protect from cerebral ischemia by upregulation of endothelial type III nitric oxide synthase (eNOS), but the downstream mechanisms have not been determined. Therefore, we investigated whether antithrombotic effects contribute to stroke protection by statins.
Methods—129/SV wild-type and eNOS knockout mice were treated with atorvastatin for 14 days (0.5, 1, and 10 mg/kg). eNOS mRNA from aortas and platelets was measured by reverse-transcriptase polymerase chain reaction. Platelet factor 4 (PF 4) and ß-thromboglobulin (ß-TG) in the plasma were quantified by ELISA. Transient cerebral ischemia was induced by filamentous occlusion of the middle cerebral artery followed by reperfusion.
Results—Stroke volume after 1-hour middle cerebral artery occlusion/23-hour reperfusion was significantly reduced by 38% in atorvastatin-treated animals (10 mg/kg) compared with controls. Serum cholesterol levels were not affected by the treatment. eNOS mRNA was significantly upregulated in a dose-dependent manner in aortas and in thrombocytes of statin-treated mice compared with controls. Moreover, indices of platelet activation in vivo, ie, plasma levels of PF 4 and ß-TG, were dose-dependently downregulated in the treatment group. Surprisingly, atorvastatin-treatment did not influence PF 4 and ß-TG levels in eNOS knockout mice.
Conclusions—The synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin upregulates eNOS in thrombocytes, decreases platelet activation in vivo, and protects from cerebral ischemia in normocholesterolemic mice. Antithrombotic and stroke-protective effects of statins are mediated in part by eNOS upregulation. Our results suggest that statins may provide a novel prophylactic treatment strategy independent of serum cholesterol levels.
Key Words: blood platelets • cerebral ischemia • HMG-CoA reductase inhibitors • nitric oxide • thrombosis
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
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Agrowing body of evidence suggests that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, exert beneficial vascular effects that are independent of their cholesterol-lowering potencies.1 2 3 4 5 6 Thus far, the relevance of cholesterol as a stroke risk factor has remained controversial,7 8 and several intervention trials with non-statin lipid-lowering drugs failed to demonstrate a reduction in stroke incidence.9 10 Recent trials demonstrated that statins lower the risk of stroke up to 42% in patients with coronary heart disease.11 Surprisingly, statins significantly reduced cardiovascular events even in patients with average cholesterol levels.12 13 14 It has been suggested that the protective mechanism(s) may relate to improved endothelial function and/or antithrombotic effects,1 2 3 4 5 6 but the mechanism of the cholesterol-independent effects of statins is not clear.
Upregulation of endothelial type III nitric oxide synthase (eNOS) was recently identified as a novel mechanism of action of statins in vitro and in vivo.15 16 17 18 19 Endothelium-derived NO has been shown to regulate blood pressure, augment regional blood flow, improve cerebral circulation, decrease leukocyte activation, and inhibit platelet aggregation.20 21 22 23 24 Accordingly, animals lacking eNOS expression (eNOS knockout mice) suffer from arterial hypertension, develop enlarged cerebral infarcts after occlusion of the middle cerebral artery, and have enhanced hemostasis.20 24 25 Indeed, eNOS upregulation by statins augments cerebral blood flow in mice as a potential mechanism of stroke protection.15 26 Since thrombosis superimposed on atherosclerosis causes approximately two thirds of all brain infarctions,27 we investigated whether antithrombotic effects contribute to the protective effects of statins in vivo.
ß-Thromboglobulin (ß-TG) and platelet factor 4
(PF 4) are 2 platelet-specific proteins that are secreted from the
-granules during the release reaction induced by ADP,
epinephrine, arachidonic acid, collagen, and
thrombin.28 Plasma levels of these factors are established
and valid indices of platelet activation in vivo.28
Hence, we investigated whether increased eNOS activity induced by
statins would regulate markers of platelet activation. Moreover, we
hypothesized that the source of increased NO production after
statin treatment is not only the endothelium but also
the blood platelets themselves. In fact, active type III NOS has
recently been identified in human platelets,29 and NO
released from activated platelets inhibits platelet
recruitment to a growing thrombus.30
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
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Drugs
Atorvastatin was a gift from Gödecke AG Freiburg. Stock solutions (2 mg/mL) were prepared in PBS and 5% (vol/vol) ethanol (pH 7.6).
Animals and Drug Treatment
Animal experiments were conducted in strict accordance with
national and institutional guidelines. 129/SV wild-type (weight, 18 to
22 g) or eNOS knockout mice20 were treated with
atorvastatin (0.5, 1, and 10 mg/kg) or a corresponding volume of
vehicle by daily subcutaneous injections for 14 days. Serum
cholesterol levels were determined by the Institut
für Klinische Chemie, Universität zu Köln,
Germany.
Ischemia Model
Animals were anesthetized for induction with 1.5%
halothane and maintained in 1.0% halothane in 70%
N2O and 30% O2 with a
vaporizer. Ischemia experiments were essentially performed as
described.15 31 In brief, brain ischemia was
induced with an 8.0 nylon monofilament coated with a silicone
resin/hardener mixture (Xantopren M Mucosa and Activator NF
Optosil Xantopren, Haereus Kulzer) as
described.15 31 The filament was introduced into the left
internal carotid artery up to the anterior cerebral artery, thereby
occluding the middle cerebral artery and anterior choroidal arteries.
Filaments were withdrawn after 1 hour of ischemia to allow
reperfusion. Regional cerebral blood flow measured by laser-Doppler
flowmetry (Perimed) fell to <20% during ischemia and
returned to approximately 100% within 5 minutes after reperfusion in
either group (P>0.05). Core temperature during the
experiment was maintained at 36.5±0.5°C with a feedback temperature
control unit.
Infarct Measurements
For infarct measurements after 23 hours of reperfusion, animals
were deeply anesthetized by halothane anesthesia
(4%) and decapitated. The brains were divided into 5 coronal 2-mm
sections with the use of a mouse brain matrix (RBM-2000C, Activational
Systems) and stained with
2,3,5-triphenyltetrazolium chloride
(Sigma). Infarct volumes were quantified with an image analysis
system (SigmaScan Pro 4.0, Jandel Scientific) and calculated by summing
the volumes of each section directly or indirectly as
described.15 31 Differences between "direct" and
"indirect" volumes are likely to be accounted for by brain
swelling.
Experimental Thrombosis
Experimental thrombosis was induced by ligature of the
inferior vena cava, as described elsewhere.32
Mice were anesthetized with halothane as described above, and
the abdomen was surgically opened on the median line. After a careful
dissection, a tight ligature (with a cotton thread) was placed around
the inferior vena cava, just below the left renal vein. Two
hours later, the abdomen was reopened under anesthesia. The
thrombus, if present, was removed, washed in distilled water,
blotted on filter paper, and placed in a desiccator; 24 hours later,
the dry weight of the thrombus was recorded.
Preparation of Platelet-Poor Plasma and Platelet-Rich
Plasma
Animals were deeply anesthetized with 0.1 mL chloral
hydrate (7% wt/vol in PBS) by intraperitoneal
injection. Whole blood was withdrawn by puncture of the retro-orbital
plexus. For PF 4 and ß-TG measurements, anticoagulation was performed
with modified Edinburgh anticoagulant (10% vol/vol; Hemogard CTAD,
Diatube H, Becton Dickinson, Diagnostica Stago, reference
367599). After 15 minutes of incubation at 4°C, blood was
centrifuged at 2000g for 30 minutes (4°C). Only
the medium phase of the supernatant (platelet-poor plasma) was
withdrawn with a pipette and stored at -70°C until further use.
For preparation of platelet-rich plasma (PRP), blood was immediately anticoagulated with trisodium citrate (10% vol/vol of a solution containing 130 mmol/L citric acid, 125 mmol/L trisodium citrate, and 110 mmol/L glucose). Blood was centrifuged (150g, 6 minutes, 22°C), and the supernatant, which represents PRP, was separated. Counting of platelets and white (WBC) and red blood cells (RBC) in PRP was performed with a Celldyn3500 analyzer (Abbott; auxiliary mode). The concentration of both WBC and RBC in PRP was negligible (WBC, 0.004±0.001x103/µL; RBC, 0.007±0.002x106/µL; platelets, 110±23x103/µL). Additionally, platelets were examined under phase contrast microscopy to check for contamination of other blood cells; a few RBC but virtually no WBC were detected.
Measurement of Plasma Levels of PF 4 and ß-TG
PF 4 was quantified in CTAD plasma with the use of the
Asserachrom PF4 ELISA from Roche, Diagnostica Stago
(reference 1875 353). ß-TG was quantified in CTAD plasma with the use
of the Asserachrom ß-TG ELISA from Roche, Diagnostica
Stago (reference 1875 370). The assay and calculation of results were
performed according to the manufacturer’s instructions.
Reverse-Transcriptase Polymerase Chain Reaction
Aortas were quickly frozen after the animals were killed.
Isolated platelets from PRP were dissolved in RNA-clean (AGS) and
stored at -70°C until RNA preparation. Total RNA isolation, reverse
transcription, and competitive polymerase chain reaction (PCR) was
performed according to standard techniques.16 The sense
(5'-TTCCGGCTGCCACCTGATCCTAA-3') and antisense (5'-AACATATGTCC
TTGCTCAAGGCA-3') primers were used to amplify a 340-bp murine eNOS cDNA
fragment and a 1052-bp mutated eNOS cDNA that served as internal
standard. Glyceraldehyde 3-phosphate dehydrogenase
(GAPDH) was amplified as an external standard as
described.17 Each PCR cycle consisted of denaturing at
94°C for 30 seconds, annealing at 60°C for 30 seconds, and
elongation at 72°C for 60 seconds. The linear exponential phases for
eNOS and GAPDH PCR were 35 and 22 cycles, respectively. Equal amounts
of corresponding NOS and GAPDH reverse transcriptase PCR (RT-PCR)
products were loaded on 1.5% agarose gels, and optical densities
of ethidium-bromide–stained DNA bands were quantified and expressed as
mean±SEM of the ratio of murine eNOS to eNOS mutant PCR signal.
Rho GTP-Binding Assay
The Rho GTP-binding activity was determined by
immunoprecipitation of [35S]GTP
S-labeled
Rho.17 Aortas were quickly isolated and snap-frozen in
isopentane on dry ice. Briefly, membrane and cytosolic proteins were
isolated and incubated (20 µg) for 30 minutes at 37°C in a buffer
containing [35S]GTPS (20 nmol/L), GTP
(2 µmol/L), MgCl2 (5 mmol/L), EGTA
(0.1 mmol/L), NaCl (50 mmol/L), creatinine
phosphate (4 mmol/L), phosphocreatine kinase (5 U), ATP (0.1
mmol/L), dithiothreitol (1 mmol/L), leupeptin (100 µg/mL),
aprotinin (50 µg/mL), and phenylmethylsulfonyl fluoride
(2 mmol/L). The assay was terminated with excess unlabeled GTPS
(100 µmol/L). Samples were then resuspended in 100 µL of
immunoprecipitation buffer containing Triton-X (1%), SDS (0.1%), NaCl
(150 mmol/L), EDTA (5 mmol/L), Tris-HCl (25 mmol/L, pH
7.4), leupeptin (10 µg/mL), aprotinin (10 µg/mL), and
phenylmethylsulfonyl fluoride (2 mmol/L). The RhoA
antiserum was added to the mixture at a final dilution of 1:75. The
samples were allowed to incubate for 16 hours at 4°C with gentle
mixing. The antibody-G-protein complexes were then incubated with 50
µL of protein A-Sepharose (1 mg/mL, Pharmacia Biotech Inc) for 2
hours at 4°C, and the immunoprecipitate was collected by
centrifugation at 12 000g for 10 minutes.
The pellets were washed 4 times in a buffer containing HEPES (50
mmol/L, pH 7.4), NaF (100 µmol/L), sodium phosphate (50
mmol/L), NaCl (100 mmol/L), Triton X-100 (1%), and SDS (0.1%).
The final pellet containing the immunoprecipitated
[35S]GTPS-labeled Rho proteins was counted
in a liquid scintillation counter (LS 1800, Beckman Instruments, Inc).
Nonspecific activity was determined in the presence of excess unlabeled
GTPS (100 µmol/L).
Data Analysis
Data are presented as mean±SEM. Comparisons were made
by 2-tailed Student’s t test and ANOVA. P<0.05
was considered statistically significant.
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Results |
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Atorvastatin Protects From Cerebral Ischemia/Reperfusion
To evaluate whether chronic pretreatment with the synthetic statin atorvastatin confers protection after stroke, 129/SV wild-type mice were injected daily with atorvastatin (10 mg/kg SC) for 14 days. Under these treatment conditions, serum cholesterol levels were not significantly altered (87.8±15.4 versus 89.5±8.5 mg/dL in atorvastatin- versus vehicle-treated mice, respectively; n=4 animals). Animals were subjected to 1-hour middle cerebral artery occlusion followed by 23 hours of reperfusion. Lesion volume was determined after 24 hours on 2,3,5-triphenyltetrazolium–stained 2-mm coronal brain sections by computer-assisted volumetry. Direct lesion volume was reduced by 38% in atorvastatin-treated animals (Figure 1a
). Significantly smaller lesions were
evident in 2 (ie, sections 2 and 3) of the 5 standardized coronal brain
sections (Figure 1b). When infarction volume was corrected for
brain swelling (ie, calculated with the indirect method), infarcts in
the atorvastatin-treated group were still significantly decreased by
35% (50.2±7.8 versus 77.6±10.8 mm3 in
atorvastatin- versus vehicle-treated mice, respectively; n=12 and 9
animals; P<0.05).
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) compared with vehicle-injected mice
(
). Infarcts were also smaller after correction for brain swelling
by an indirect method to measure infarct size. Data are
presented as mean and SEM; n=9 (control) and 12
(atorvastatin-treated) animals. *P<0.05,
**P<0.01 compared with vehicle-injected mice.
Atorvastatin Upregulates eNOS mRNA Expression in Aortas
To examine whether treatment with atorvastatin regulates
eNOS expression in the vasculature, eNOS mRNA levels were determined in
the aorta by RT-PCR (Figure 2a).
Treatment with atorvastatin (0.5, 1, and 10 mg/mg) dose-dependently
upregulated eNOS RNA by 1.1-, 1.7-, and 2.3-fold, respectively (n=4 to
8 animals; P<0.05 for 10 mg/kg versus control) (Figure 2b).
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Atorvastatin Inhibits Rho GTPase Activity in Aortas
We previously demonstrated in vitro that the mechanism by which
statins increase eNOS expression relates to the inhibition of
geranylgeranylation of the small GTP-binding protein
Rho.15 16 However, it is not known whether statin
treatment indeed inhibits Rho function in the vessel wall. Hence, to
investigate whether atorvastatin would decrease Rho GTPase activity in
vivo, we performed GTP-binding assays in mouse aortas after
atorvastatin pretreatment. In fact, Rho GTPase activity was
significantly inhibited by atorvastatin pretreatment (10 mg/kg for 14
days) (Figure 3). In accordance with the
in vitro evidence, these results suggest that atorvastatin upregulates
eNOS expression by inhibition of Rho isoprenylation.
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Atorvastatin Upregulates eNOS mRNA in Platelets In
Vivo
NO is a mediator of platelet function and is released from
platelets in vivo.29 Therefore, we determined whether
platelets from 129/SV wild-type mice treated with atorvastatin for
14 days contain higher levels of eNOS mRNA (Figure 4a). Indeed, RT-PCR analysis
revealed that treatment with atorvastatin (0.5, 1, and 10 mg/kg)
significantly increased the eNOS in platelets by 1.2-, 1.8-, and
3.2-fold, respectively (n=4 to 8 animals; P<0.05 for 10
mg/kg versus control) (Figure 4b).
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Atorvastatin Downregulates Indices of Platelet Activation In
Vivo and Inhibits Thrombus Formation
To determine whether the increased expression of type III NOS in
the aorta and platelets after statin treatment have an effect on
platelet function, 2 markers of platelet activity, ie, PF 4 and
ß-TG, were quantified in plasma by means of ELISA. Compared with
vehicle, we found that PF 4 was decreased by 15%, 24%, and 57% after
treatment (14 days) with atorvastatin at 0.5, 1.0, and 10 mg/kg,
respectively (17.8±0.3 versus 15.1±0.7 versus 13.5±7.7 versus
7.7±1.0 IU/mL in vehicle-treated versus 0.5, 1, and 10 mg/kg
atorvastatin-treated mice, respectively; n=4 to 10 animals;
P<0.05 for 1 and 10 mg/kg versus control) (Figure 5a). Similarly, atorvastatin
treatment reduced the plasma levels of ß-TG compared with control by
8%, 20%, and 31% (2.6±0.2 versus 2.4±0.4 versus 2.1±0.3 versus
1.6±0.2 IU/mL vehicle-treated versus atorvastatin-treated mice,
respectively; n=4 to 10 animals; P<0.05 for 1 and 10 mg/kg
versus control) (Figure 5b).
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Additionally, we subjected mice to experimental thrombosis after treatment with atorvastatin (10 mg/kg for 14 days) or vehicle. While thrombus formation was observed in all vehicle-injected mice (9/9 mice; thrombus weight=1.8±0.4 mg), thrombus formation was observed in only 25% of atorvastatin-treated mice (2/8 mice; thrombus weight=1.1±0.2 mg).
No Antithrombotic Effects of Statins in eNOS Knockout Mice
To test whether the regulation of platelet function by
atorvastatin treatment was indeed mediated by NO produced by type III
NOS, eNOS knockout
(eNOS-/-) mice were
subjected to the same treatment protocol with atorvastatin (10 mg/kg,
14 days). Surprisingly, atorvastatin did not alter plasma levels of PF
4 (Figure 6a) (n=4 animals) or the
levels of ß-TG (Figure 6b) (n=4 animals). These findings
suggest that most, if not all, effects of atorvastatin on platelet
activity were mediated by eNOS.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
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This study shows that treatment with the synthetic HMG-CoA reductase inhibitor atorvastatin decreases platelet activation and protects wild-type mice from cerebral ischemia. Atorvastatin treatment did not significantly alter cholesterol levels. Thus, reduction of platelet activation in our model is unrelated to the lipid-lowering properties of statins. Surprisingly, atorvastatin had no effect on platelet activation in eNOS knockout mice, demonstrating that the underlying mechanism is indeed the upregulation of type III NOS by statin treatment.
These findings extend our previous data showing stroke protection in mice with simvastatin pretreatment,15 demonstrating a class effect for HMG-CoA reductase inhibitors. Atorvastatin, however, differs significantly from simvastatin (or lovastatin) in both structure and pharmacology because it is a "synthetic" and not a "natural" statin33 and does not cross the blood-brain barrier.34 Hence, direct parenchymal neuroprotective effects of atorvastatin as mechanism of stroke reduction seem unlikely. Only after the onset of cerebral ischemia may atorvastatin enter the brain parenchyma because of blood-brain barrier breakdown. In conclusion, our data indicate that the neuroprotective mechanisms of atorvastatin are predominantly mediated by NO-dependent effects of statins on hemostasis and blood flow.
The mechanism by which HMG-CoA reductase inhibitors increase eNOS expression is the inhibition of geranylgeranylpyrophosphate (GGPP), an isoprenoid intermediate of the cholesterol synthesis pathway.35 GGPP is important for the posttranslational modification of the small GTP-binding protein Rho,36 and Rho negatively regulates eNOS mRNA stability.17 In this study we demonstrate that atorvastatin treatment significantly inhibits Rho activity in the vessel wall in vivo. Therefore, in vitro and in vivo evidence suggests that statins upregulate endothelial NO production by inhibition of Rho isoprenylation independent of cholesterol synthesis.15 17 37
Both type III (endothelial) and type II (inducible) NOS have been identified in human platelets and megakaryocytic cells.29 38 39 40 Platelet-derived type III NOS has been shown to regulate platelet function.25 30 Accordingly, incubation of platelets with the NOS substrate L-arginine inhibits platelet aggregation,22 whereas the NOS inhibitor NG-monomethyl-L-arginine enhances platelet reactivity.40 NO release from activated platelets markedly inhibits platelet recruitment and thus may limit the progression of intra-arterial thrombosis.30 Although the role of endothelium-derived NO has been extensively characterized, relatively little is known about the regulation of platelet-derived NO. In this study we show that pharmacological intervention, ie, inhibition of the mevalonate pathway by HMG-CoA reductase inhibitors, upregulates type III NOS expression in platelets in vivo. The associated decrease of 2 markers of platelet activation, PF 4 and ß-TG, and the fact that thrombus formation was inhibited demonstrate the functional relevance of this observation. Platelet reactivity was indeed regulated by eNOS because PF 4 and ß-TG plasma levels were not affected by statin treatment in eNOS knockout mice. Thus, we identify platelet-derived NO as a novel target for drug interventions.
Thrombosis superimposed on atherosclerosis is a key event in the pathogenesis of cerebral infarctions.27 The use of antiplatelet drugs is a well-established therapy for the secondary prevention of stroke.41 Recent evidence points toward the importance of platelet aggregation not only during cerebral ischemia but also as the acute precipitating event in most acute coronary syndromes. The development of acute coronary syndromes is attributed to thrombus formation on a fissured, eroded, or ruptured plaque in the coronary artery.42 Indeed, platelet activation is increased in patients with unstable angina pectoris.43 Therefore, patients at risk for both stroke and myocardial infarction significantly benefit from inhibition of platelet aggregation.41 44
Hypercholesterolemia has recently been linked to platelet function because it facilitates platelet aggregation.45 Moreover, several recent studies have demonstrated beneficial effects of statin therapy on platelet function and fibrinolysis in hypercholesterolemic individuals.45 46 47 48 49 50 51 Our findings, by contrast, demonstrate that statins inhibit platelet activation independent of serum cholesterol levels by upregulation of type III NOS. Therefore, our data may have direct clinical implications: eNOS upregulation may be the mechanism of protection in patients with average cholesterol levels, as observed in large statin trials.12 13 In fact, we suggest that the decreased incidence of cerebrovascular events observed in these trials may in part be due to a reduction of cerebral infarct size to levels that are clinically unappreciated. In conclusion, our findings suggest that patients at risk for stroke or acute coronary syndromes may benefit from statin treatment regardless of their serum cholesterol levels.
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Acknowledgments |
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This research was supported by the Deutsche Forschungsgemeinschaft (La 1057/4-1 to U.L., En 343/4-1 and En 343/6-1 to M.E.), the Humboldt-University (99755128 and 99755157 to M.E.), the Köln Fortune Program (to U.L.), the Bundesministerium für Bildung, Forschung, und Technologie (to M.E., U.D., and U.L.), and the Hermann and Lilly Schilling Stiftung (to U.D.). We thank Michael A. Moskowitz and James K. Liao for advice.
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Footnotes |
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Reprint requests to Matthias Endres, MD, Klinik und Poliklinik für Neurologie der Charité, Humboldt-Universität zu Berlin, Schumannstr 20/21, D-10098 Berlin, Germany.
Received March 16, 2000; revision received June 19, 2000; accepted June 20, 2000.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
|---|
1. Vaughan CJ, Murphy MB, Buckley BM. Statins do more than just lower cholesterol. Lancet. 1996;348:1079–1082.[Medline] [Order article via Infotrieve]
2.
Delanty N, Vaughan CJ. Vascular effects of statins in
stroke. Stroke. 1997;28:2315–2320.
3. Crouse JR III, Byington RP, Furberg CD. HMG-CoA reductase inhibitor therapy and stroke risk reduction: an analysis of clinical trials data. Atherosclerosis. 1998;138:11–24.[Medline] [Order article via Infotrieve]
4. Blauw GJ, Lagaay AM, Westendorp RGJ. Statins for prevention of stroke. Lancet. 1998;352:144. Letter.
5.
Vaughan CJ, Delanty N. Neuroprotective properties of
statins in cerebral ischemia and stroke. Stroke. 1999;30:1969–1973.
6.
Hess DC, Demchuk AM, Brass LM, Yatsu FM. HMG-CoA
reductase inhibitors (statins): a promising approach to
stroke prevention. Neurology.. 2000;54:790–796.
7. Prospective Studies Collaboration. Cholesterol, diastolic blood pressure, and stroke: 13,000 strokes in 450,000 people in 45 prospective studies. Lancet. 1995;346:1647–1653.[Medline] [Order article via Infotrieve]
8.
Hachinski V, Graffagnino C, Beaudry M, Bernier G, Buck
C, Donner A, Spence D, Doid G, Wolfe BMF. Lipids and stroke: a paradox
resolved. Arch Neurol. 1996;53:303–308.
9.
Atkins D, Psaty BM, Koepsel TD, Longstreth WT, Larson
EB. Cholesterol reduction and the risk for stroke in men.
Ann Intern Med. 1993;119:136–145.
10.
Hebert PR, Gaziano JM, Chan KS, Hennekens CH.
Cholesterol lowering with statins drugs, risk of stroke,
and total mortality. JAMA. 1997;278:313–321.
11.
Kearney D, Fitzgerald D. The anti-thrombotic effects of
statins. J Am Coll Cardiol. 1999;33:1305–1307.
12.
Cholesterol and Recurrent Events
Investigators. The effect of pravastatin on
coronary events after myocardial infarction in patients with
average cholesterol levels. N Engl J
Med. 1996;335:1001–1009.
13.
The Long Term Intervention with Pravastatin
in Ischemic Disease (LIPID) Study Group. Prevention of
cardiovascular events and death with
pravastatin in patients with coronary heart disease
and a broad range of initial cholesterol levels.
N Engl J Med. 1998;339:1349–1357.
14. Scandinavian Simvastatin Survival Group. Randomized trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet. 1994;344:1383–1389.[Medline] [Order article via Infotrieve]
15.
Endres M, Laufs U, Huang Z, Nakamura T, Huang P,
Moskowitz MA, Liao JK. Stroke protection by 3-hydroxy-3-methylglutaryl
(HMG)-CoA reductase inhibitors mediated by
endothelial nitric oxide synthase. Proc Natl Acad
Sci U S A. 1998;95:8880–8885.
16.
Laufs U, La FV, Plutzky J, Liao JK. Upregulation of
endothelial nitric oxide synthase by HMG CoA reductase
inhibitors. Circulation. 1998;97:1129–1135.
17.
Laufs U, Liao JK. Post-transcriptional regulation of
endothelial nitric oxide synthase mRNA stability by Rho
GTPase. J Biol Chem. 1998;273:24266–24271.
18.
Laufs U, Marra D, Node K, Liao JK.
3-Hydroxy-3-methylglutaryl-CoA reductase inhibitors
attenuate vascular smooth muscle proliferation by preventing Rho
GTPase-induced down-regulation of p27(Kip1). J Biol
Chem. 1999;274:21926–21931.
19. Hernandez-Perera O, Perez-Sala D, Navarro-Antolin J, Sanchez-Pascuala R, Hernandez G, Diaz C, Lamas S. Effects of the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, atorvastatin and simvastatin, on the expression of endothelin-1 and endothelial nitric oxide synthase in vascular endothelial cells. J Clin Invest. 1998;101:2711–2719.[Medline] [Order article via Infotrieve]
20. Huang PL, Huang Z, Mashimo H, Bloch KD, Moskowitz MA, Bevan JA, Fishman MC. Hypertension in mice lacking the gene for endothelial nitric oxide synthase. Nature. 1995;377:239–242.[Medline] [Order article via Infotrieve]
21. Morikawa E, Moskowitz MA, Huang Z, Yoshida T, Irikura K, Dalkara T. L-Arginine infusion promotes nitric oxide–dependent vasodilation, increases regional cerebral blood flow, and reduces infarction volume in the rat. Stroke. 1994;25:429–435.[Abstract]
22.
Randomski MW, Palmer RM, Moncada S. An
L-arginine/nitric oxide pathway present in human platelets
regulates aggregation. Proc Natl Acad Sci U S A. 1990;87:5193–5197.
23.
Liao JK. Endothelium and acute
coronary syndromes. Clin Chem. 1998;44:1799–1808.
24. Huang Z, Huang PL, Ma, J, Meng W, Ayata C, Fishman MC, Moskowitz MA. Enlarged infarcts in endothelial nitric oxide synthase knockout mice are attenuated by nitro-L-arginine. J Cereb Blood Flow Metab. 1996;16:981–987.[Medline] [Order article via Infotrieve]
25.
Freedman JE, Sauter R, Battinelli EK, Ault K,
Knowles C, Huang PL, Loscalzo J. Deficient platelet-derived nitric
oxide and enhanced hemostasis in mice lacking the NOS III gene.
Circ Res. 1999;84:1416–1421.
26. Yamada M, Huang Z, Dalkara T, Endres M, Laufs U, Waeber C, Huang PL, Liao JK, Moskowitz MA. Endothelial nitric oxide synthase-dependent cerebral blood flow augmentation by L-arginine after chronic statin treatment. J Cereb Blood Flow Metab.. 2000;20:709–717.[Medline] [Order article via Infotrieve]
27. Haberl RL, Dembowski K. Atherothrombosis: common factor in stroke, myocardial infarction and peripheral vascular disease. Eur Heart J. 1999;1(suppl A):A41–A44.
28.
Kaplan KL, Owen J. Plasma levels of
ß-thromboglobulin and platelet factor 4 as
indices of platelet activation in vivo. Blood. 1981;57:199–202.
29. Sase K, Michel T. Expression of constitutive endothelial nitric oxide synthase in human blood platelets. Life Sci. 1995;57:2049–2055.[Medline] [Order article via Infotrieve]
30. Freedman JE, Loscalzo J, Barnard MR, Alpert C, Keaney JF Jr, Michelson AD. Nitric oxide released from activated platelets inhibits platelet recruitment. J Clin Invest. 1997;100:350–356.[Medline] [Order article via Infotrieve]
31. Endres M, Fink K, Zhu J, Stagliano NE, Bondada V, Geddes JW, Azuma T, Mattson MP, Kwiatkowski DJ, Moskowitz MA. Neuroprotective effects of gelsolin during murine stroke. J Clin Invest. 1999;103:347–354.[Medline] [Order article via Infotrieve]
32. Wollny T, Aiello L, Di Tommaso D, Bellavia V, Rotilio D, Donati MB, de Gaetano G, Iacoviello L. Modulation of haemostatic function and prevention of experimental thrombosis by red wine in rats: a role for increased nitric oxide production. Br J Pharmacol. 1999;127:747–755.[Medline] [Order article via Infotrieve]
33.
Furberg CD. Natural statins and stroke risk.
Circulation. 1999;99:185–188.
34.
Knopp RH. Drug treatment of lipid disorders.
N Engl J Med. 1999;341:498–511.
35. Goldstein JL, Brown MS. Regulation of the mevalonate pathway. Nature. 1990;343:425–430.[Medline] [Order article via Infotrieve]
36.
Hall A. Rho GTPases and the actin cytoskeleton.
Science. 1998;279:509–514.
37.
Essig M, Nguyen G, Prie D, Escoubet B, Sraer JD,
Friedlander G. 3-Hydroxy-3-methylglutaryl coenzyme A reductase
inhibitors increase fibrinolytic activity in rat aortic
endothelial cells: role of geranylgeranylation and Rho
proteins. Circ Res. 1998;83:683–690.
38.
Chen LY, Mehta P, Mehta JL. Oxidized LDL decreases
L-arginine uptake and nitric oxide synthase protein expression in human
platelets: relevance of the effect of oxidized LDL on platelet
function. Circulation. 1996;93:1740–1746.
39. Malinski T, Radomski MW, Taha Z, Moncada S. Direct electrochemical measurement of nitric oxide released from human platelets. Biochem Biophys Res Commun. 1993;194:960–965.[Medline] [Order article via Infotrieve]
40. Simon DI, Stamler JS, Loh E, Loscalzo J, Francis SA, Creager MA. Effect of nitric oxide synthase inhibition on bleeding time in humans. J Cardiovasc Pharmacol. 1995;26:339–349.[Medline] [Order article via Infotrieve]
41.
Patrono C. Aspirin as an antiplatelet drug.
N Engl J Med. 1994;330:1287–1294.
42. Libby P, Sukhova G, Lee RT, Liao JK. Molecular biology of atherosclerosis. Int J Cardiol. 1997;62(suppl 2):S23–S29.
43.
Freedman JE, Ting B, Hankin B, Loscalzo J, Keaney JF,
Vita JA. Impaired platelet production of nitric oxide
predicts presence of acute coronary syndromes.
Circulation. 1998;98:1481–1486.
44. Salomon DH, Hart RG. Antithrombotic therapies for stroke prevention. Curr Opin Neurol. 1994;7:48–53.[Medline] [Order article via Infotrieve]
45.
Lacoste L, Lam JY, Hung K, Letchacovski G,
Solymoss CB, Waters D. Hyperlipidemia and
coronary disease: correction of the increased thrombogenic
potential with cholesterol reduction.
Circulation. 1995;92:3172–3177.
46. Aviram M, Hussein O, Rosenblatt M, Schlezinger S, Hayek T, Keidar S. Interactions of platelets, macrophages, and lipoproteins in hypercholesterolemia: antiatherogenic effects of HMG-CoA reductase inhibitor therapy. J Cardiovasc Pharmacol. 1998;31:39–45.[Medline] [Order article via Infotrieve]
47. Dangas G, Smith DA, Badimon JJ, Unger AH, Shao JH, Meraj P, Cohen AM, Levine D, Fallon JT, Ambrose JA. Gender differences in blood thrombogenicity in hyperlipidemic patients and response to pravastatin. Am J Cardiol. 1999;84:639–643.[Medline] [Order article via Infotrieve]
48. Tsakiris DA, Keller U, Zulewski H, Miserez AR, Wolf F, Marbet GA. Simvastatin reduces activation of normal platelets by LDL isolated from patients with familial hypercholesterolaemia and familial defective apolipoprotein B. Eur J Clin Pharmacol. 1997;53:277–279.[Medline] [Order article via Infotrieve]
49.
Szczeklik A, Musial J, Undas A, Gajewski P, Gora P,
Swadzba J, Jankowski M. Inhibition of thrombin generation by
simvastatin and lack of additive effects of aspirin in
patients with marked hypercholesterolemia.
J Am Coll Cardiol. 1999;33:1286–1293.
50. Tannous M, Cheung R, Vignini A, Mutus B. Atorvastatin increases ecNOS levels in human platelets of hyperlipidemic subjects. Thromb Haemost. 1999;82:1390–1394.[Medline] [Order article via Infotrieve]
51.
Pitt B, Waters D, Brown WV, van BA, Schwartz L, Title
LM, Eisenberg D, Shurzinske L, McCormick LS, for the Atorvastatin
versus Revascularization Treatment Investigators.
Aggressive lipid-lowering therapy compared with angioplasty in stable
coronary artery disease. N Engl J Med. 1999;341:70–76.
Editorial Comment
Division of Cardiology, Department of Medicine Weill Medical College of Cornell University New York, New York
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
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Despite the established role of cholesterol in the pathogenesis of coronary artery disease, current epidemiological evidence does not demonstrate a clear relationship between the risk of stroke and serum cholesterol level.R1 R2 However, recent studiesR3 R4 indicate that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or "statins," significantly reduce ischemic stroke. The mechanisms underlying this reduction have not been fully elucidated and likely include the effects of statins on atherosclerotic plaque development and stability in the aorta and carotid artery.R5 Other putative effects may include beneficial actions on cerebral endothelial function, cerebral hemorheology, and effects on platelet activation and thrombosis.R6 R7 Perhaps most fascinating is the emerging body of data demonstrating effects of statins that occur independent of changes in cholesterol level. Many of these effects are thought to result from the depletion of isoprenoids. Isoprenoids are derivatives of intermediates in cholesterol biosynthesis and have a number of actions, including effects on G-proteins, adhesion molecules, and cell proliferation and signaling.R8 Some of the cellular effects of statins, including effects on nitric oxide, may be mediated by reduced isoprenoid bioavailability.
NO produced by endothelial NOS (eNOS) has a protective physiological role and orchestrates the paracrine homeostatic functions of the endothelium, which include inhibition of leukocyte and platelet adhesion, control of vascular tone, and maintenance of a thromboresistant interface between the bloodstream and the vessel wall. Consistent with the concept that eNOS plays a protective role in focal cerebral ischemia is the observation that eNOS knockout animals experience larger infarcts after middle cerebral artery occlusion.R9 In a murine model of ischemic stroke, prophylactic statin therapy with both simvastatin and lovastatin augments cerebral blood flow, reduces infarct size (by approximately 30%), and improves neurological outcome in normocholesterolemic animals.R10 This study demonstrated that statin therapy directly upregulates eNOS activity in the brain without altering expression of neuronal NOS. These effects occurred independent of changes in cholesterol level and were reversible by cotreatment with mevalonate or geranylgeranylpyrophosphate.
The preceding study corroborates these findings with use of a different statin and adds to our understanding of possible mechanisms through which statins may be protective in cerebral ischemia. This study demonstrates that atorvastatin significantly reduces stroke size in normocholesterolemic mice independent of effects on cholesterol level. This effect on ischemic stroke appears to be mediated by upregulation of eNOS in the vasculature and platelets and through decreased platelet activation. The effect on platelet eNOS is particularly interesting and suggests that the putative antithrombotic effects of statins are not exclusively due to modulation of the endothelial eNOS system. These experiments also suggest that atorvastatin upregulates vascular and platelet eNOS by reducing the isoprenylation (and hence activity) of the small GTP-binding protein rho, which itself may negatively regulate eNOS mRNA. An evolving paradigm is that of cell function orchestrated by isoprenoid metabolites derived from within the cholesterol biosynthetic pathway. This is important because it may, to some degree, explain the unresolved disparity between epidemiological studies and clinical trials of cholesterol and stroke. The emerging data from both the bedside and the bench underscore the necessity for further clinical studies to explore the impact of statin therapy in human stroke and neuroprotection.
Received March 16, 2000; revision received June 19, 2000; accepted June 20, 2000.
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferencesIntroduction References |
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1. Iso H, Jacobs DR, Wentworth D, Neaton JD, Cohen JD, for the MRFIT Research Group. Serum cholesterol levels and six year mortality from stroke in 350,977 men screened for the multiple risk factor intervention trial. N Engl J Med.. 1989;320:904–910.[Abstract]
2. Prospective Studies Collaboration. Cholesterol, diastolic blood pressure, and stroke: 13,000 strokes in 450,000 people in 45 prospective studies. Lancet.. 1995;346:1647–1653.
3. Sacks FM, Pfeffer MA, Moye LA, Rouleau JL, Rutherford JD, Cole TG, Brown L, Warnica JW, Arnold JM, Wun CC, Davis BR, Braunwald E, for the Cholesterol and Recurrent Events Trial Investigators. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med.. 1996;335:1001–1009.
4. Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet.. 1994;344:1383–1389.
5. Crouse JR III, Byington RP, Bond MG, Espeland MA, Craven TE, Sprinkle JW, McGovern ME, Furberg CD. Pravastatin, lipids, and atherosclerosis in the carotid arteries (PLAC-II). Am J Cardiol.. 1995;75:455–459.[Medline] [Order article via Infotrieve]
6. Delanty N, Vaughan CJ. Vascular effects of statins in stroke. Stroke.. 1997;28:2315–2320.
7. Vaughan CJ, Murphy MB, Buckley BM. Statins do more than just lower cholesterol. Lancet.. 1996;348:1079–1082.
8.
Vaughan CJ, Gotto AM Jr, Basson CT. The evolving role
of statins in the management of atherosclerosis.
J Am Coll Cardiol.. 2000;35:1–10.
9. Huang PL, Huang ZH, Ma J, Meng W, Ayata C, Fishman MC, Moskowitz MA. Enlarged infarcts in endothelial nitric oxide synthase knockout mice are attenuated by nitro-L-arginine. J Cereb Blood Flow Metab.. 1996;16:981–987.
10. Endres M, Laufs U, Huang Z, Nakamura T, Huang P, Moskowitz MA, Liao JK. Stroke protection by 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitors mediated by endothelial nitric oxide synthase. Proc Natl Acad Sci U S A. 1998;95–8880-8885.
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|
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