(Circulation. 2001;103:2248.)
© 2001 American Heart Association, Inc.
Clinical Investigation and Reports |
Simvastatin Depresses Blood Clotting by Inhibiting Activation of Prothrombin, Factor V, and Factor XIII and by Enhancing Factor Va Inactivation
From the Department of Medicine, Jagiellonian University School of Medicine, Cracow, Poland (A.U., J.M., A.S.), and the Department of Biochemistry, University of Vermont, Burlington (K.E.B., K.G.M.).
Correspondence to Kenneth G. Mann, PhD, University of Vermont, Department of Biochemistry, Given Bldg, Room E407, Burlington, VT 05405. E-mail kmann{at}protein.uvm.edu
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Abstract |
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Background—The mechanism of the antithrombotic action of statins is unclear. The aim of this study was to evaluate the effects of simvastatin on the coagulation process at sites of microvascular injury.
Methods and
Results—Tissue factor–initiated coagulation
was assessed in blood samples collected every 30 seconds from
bleeding-time wounds of 17 patients who had advanced coronary
artery disease and total cholesterol levels of 224.6±11.8
mg/dL (mean±SEM). Quantitative Western blotting for time courses of
fibrinogen depletion and activation of prothrombin, factor V, and
factor XIII was performed before and after 3 months of
simvastatin treatment (20 mg/d). Simvastatin
induced reductions in total cholesterol (23%) and
LDL-cholesterol (36%), which were accompanied by
significant decreases in the rates of prothrombin activation
(16.2±2.1%; P=0.004),
formation of 
-thrombin B-chain (27.4±1.8%;
P=0.001), generation of factor
Va heavy chain (29.7±3.1%;
P=0.007) and factor Va light
chain (18.9±1.2%; P=0.02),
factor XIII activation (19.8±1.3%;
P=0.001), and fibrinogen
conversion to fibrin (72.2±3%;
P=0.002). Posttreatment
fibrinopeptides A and B concentrations, determined by
using high-performance liquid chromatography,
were reduced within the last 30 seconds of bleeding. The 30-kDa
fragment of the factor Va heavy chain (residues 307 to 506), produced
by activated protein C, and the 97-kDa fragment of the factor
Va heavy chain (residues 1 to 643) were released more rapidly after
simvastatin treatment. The antithrombotic actions of
simvastatin showed no relationship to its
cholesterol-lowering action.
Conclusions—Simvastatin treatment depresses blood clotting, which leads to reduced rates of prothrombin activation, factor Va generation, fibrinogen cleavage, factor XIII activation, and an increased rate of factor Va inactivation. These effects are not related to cholesterol reduction.
Key Words: simvastatin • thrombin • factor V • factor XIII • fibrinogen
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Introduction |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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The effectiveness of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) in the prevention of coronary artery disease (CAD) is ascribed not only to reduced cholesterol levels,1 2 but also to a number of additional effects, including the stabilization of atherosclerotic plaque, improved endothelial function, enhanced fibrinolysis, and antithrombotic actions.3 4 In patients treated with statins, a marked decrease in thrombin generation has been observed,5 6 7 although its detailed characteristics and mechanisms have not been determined. Recent data suggest that statins may modulate the blood coagulation cascade, a series of reactions that proceeds through the assembly of 3 complexes of vitamin K–dependent enzymes and cofactors.8 The extrinsic coagulation pathway plays a central role in vivo. When factor VIIa encounters tissue factor (TF) exposed at the site of injury, they form the extrinsic tenase on cell membranes. This complex activates factor X and factor IX to their active forms. Factor Xa assembles with factor Va into the prothrombinase complex that converts prothrombin to
-thrombin. This enzyme activates the cofactors factor V and
factor VIII, thereby amplifying blood coagulation. In the presence of
thrombomodulin, thrombin also activates protein C, which in
turn inactivates factor Va and factor VIIIa and shuts down
further -thrombin
formation.9 -Thrombin also
cleaves the A and Bß chains of fibrinogen, releasing
fibrinopeptide A (FPA) and, more slowly,
fibrinopeptide B (FPB). The generated fibrin monomers
polymerize to form a stable clot. The resistance of the clot to plasmin
degradation depends on covalent cross-linking of the fibrin monomers.
This process is catalyzed by the active transglutaminase form of factor
XIII, which is produced by -thrombin
cleavage.10 Impaired TF expression on cultured human macrophages, which is induced by statins, has been demonstrated in vitro and has been attributed to the inhibition of the TF gene induction.11 TF-initiated thrombin generation on human monocytes was significantly depressed by simvastatin at concentrations of 10 nmol/L to 10 µmol/L.12 The effect of statins on factor V, factor XIII, and prothrombin activation, along with factor Va inactivation by activated protein C (APC), has not been reported.
The present study was undertaken to evaluate the effects of 3 months of simvastatin treatment on several coagulation reactions at sites of microvascular injury. The advantage of the model used is that coagulation can be assessed under near-physiological conditions in the presence of all the blood components and the vascular endothelium.
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Methods |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Materials
Tris-HCl, KOH, and HEPES were purchased from Sigma; Tween-20 was obtained from J.T. Baker; high-performance liquid chromatography–grade H2O and CH3CN, HClO4, and trifluoroacetic acid were from VWR. Murine monoclonal
-fibrinogen 3A was raised against the A chain of
fibrinogen.13 Murine
monoclonal -factor VaHC No. 17 and -factor
VaLC No. 9 recognize factor Va heavy chain
(residues 307 to 506) and factor Va light chain,
respectively.14 Burro
polyclonal -prethrombin-1 antibody, which recognizes prothrombin,
prethrombin 1, prethrombin 2, prothrombin fragment 2, and -thrombin
B-chain, was prepared at the Division of Hematology Research, Mayo
Clinic.15 Rabbit polyclonal
-factor XIII (D4679), which was raised against the subunit A, was a
gift from Dr Gerry Lasser (ZymoGenetics, Seattle, Wash). Horseradish
peroxidase–labeled goat antirabbit, antimouse, and antihorse IgG
antibodies were purchased from Southern Biotech. Molecular standards
were purchased from GIBCO-BRL. Chemiluminescent substrate was purchased
from NEN Life Science Products Inc.
Patients
Seventeen men, aged 39–64 years (mean, 51.6 years),
who had documented advanced CAD and
hypercholesterolemia, were studied. All
patients were required to have (1) total serum cholesterol
(TC) between 200 and 250 mg/dL and triglycerides <200
mg/dL, and (2) a previous myocardial infarction (n=10) or
hospitalization as a result of unstable angina (n=7) within the past 4
to 36 (mean=12) months before entering the study. Exclusion criteria
were secondary hypercholesterolemia, unstable
angina, uncontrolled hypertension, symptomatic congestive
heart failure, serious concomitant diseases, or treatment with agents
that interfere with coagulation profiles. None of the subjects had a
history of venous thromboembolism. All patients were treated with
aspirin (75 mg/d). Plasma fibrinogen and antithrombin III (AT-III)
levels were determined nephelometrically (Dade Behring), along with
lipids by standard methods, before and after simvastatin
therapy. Simvastatin (Zocor, Merck Sharp, and Dohme) was
administered over the course of 3 months at a dose of 20 mg/d. All
patients gave informed consent, and the protocol was approved by the
University’s Ethics Committee.
Model of Microvascular Injury
Evaluation of TF-initiated coagulation at sites of
hemostatic plug formation was performed in blood obtained from
bleeding-time wounds, which were made with a Simplate II device
(Organon Teknika) on the lateral aspect of a
forearm.16 17 All
procedures were performed by the same investigator. Blood was collected
into heparinized capillaries every 30 seconds until cessation of
bleeding and then mixed with anticoagulants, including sodium citrate,
aprotinin, chloromethylketone, and heparin
(vol/vol, 1:10), which were provided by an FPA assay kit
(Diagnostica Stago). Volumes of samples (range, 10 to 50
µL) were recorded. No correlations were found between the volume
of the samples and concentrations of the parameters
measured. Soluble and insoluble materials were separated by
centrifugation at 4°C (20 minutes at
2000g). Supernatants were
stored at -80°C for further analyses.
Gel Electrophoresis and Western
Blotting
Sodium dodecyl sulfate polyacrylamide
gel analysis was performed according to a modified Laemmli
procedure.13 18
Samples were separated on 5% to 15% linear gradient gels under
reducing or nonreducing conditions and were transferred to
nitrocellulose membranes (Bio-Rad) by using semi-dry
transfer.19 Western blotting
was performed with the primary antibodies -prethrombin 1 (7.5
µg/mL), -factor VaHC No.17 (7.5 µg/mL),
-factor VaLC No.9 (7.5 µg/mL), -factor
XIII (5 µg/mL), and -fibrinogen 3A (1.5 µg/mL). Time courses of
factor Va light and heavy chain generation, prothrombin activation,
fibrinogen cleavage, and factor XIII activation were analyzed
and quantified by densitometry of immunoblots on a
Hewlett-Packard Scanjet
4C/T.13 Concentrations were
estimated from serial dilutions of purified standard proteins by
horizontal comparison of sample band density. Relative concentrations
were determined by normalizing the data with regard to the maximum.
Changes in the reaction rates were analyzed using IGOR Pro
Version 3.1 software (WaveMetrics Inc). A mean value was calculated
from the compilation of 30-s interval densitometric
analysis.
High-Performance Liquid
Chromatography Analysis for
Fibrinopeptides
Peptides from supernatants collected from the last
30-s interval were separated by reverse-phase
chromatography, as described
previously.20 FPA and FPB
were identified with matrix-assisted laser desorption ionization–time
of flight (MALDI-TOF) mass spectrometry (linear model, PE Applied
Biosystems) and were quantitated as described
previously.20
Statistical Analysis
All results were expressed as means±SEM unless
otherwise stated. Differences between parameters before and
after simvastatin treatment were analyzed with the
Wilcoxon matched pairs test. Correlations were determined with
the Spearman’s rank correlation test. Statistical significance was
accepted at a level of
P<0.05.
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Results |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Three months of treatment with simvastatin (20 mg/d) resulted in a significant decrease in TC (from 224.6±11.8 mg/dL to 172.7±8.1 mg/dL; P<0.00001) and LDL-cholesterol (from 139.2±5.0 mg/dL to 89.3±4.3 mg/dL; P<0.000001), whereas triglycerides and HDL-cholesterol remained unaltered. There were no simvastatin-induced changes in platelet count (242 000±19 000 cells/µL versus 253 000±13 000 cells/µL), fibrinogen (2.72±0.12 g/L versus 2.68±0.15 g/L), or AT-III (0.23±0.02 g/L versus 0.27±0.02 g/L). Bleeding time became prolonged from 382±17 s to 419±21 s (P=0.04) after the simvastatin treatment, although sample volumes remained unaltered.
Prothrombin and Its Activation
Products
The prothrombin activation products -thrombin
B-chain (FIIa-B, relative molecular weight
(Mr)=30 000), prethrombin 2, residues 274 to
579 in the prothrombin molecule (pre-2,
Mr=36 000), and fragment 1.2 (factor 1.2,
Mr=37 000) were detected on
immunoblots in all patients 
120 s after incisions
(Figure 1
, left lane 5A). The mobility of these fragments was
identical to that in the whole blood model with the same
antibody.13
Simvastatin treatment resulted in a 60-s delay in the
appearance of the prothrombin activation products
(Figure 1A, lanes 1B to 9B). Densitometry on
immunoblots of -thrombin B-chain before treatment showed
that, after a lag phase, it appeared rapidly and reached a maximum of
40 nmol/L before the cessation of bleeding
(Figure 1B). Simvastatin decreased the rate of
thrombin formation by 27.4±1.8% (0.237 nmol ·
L-1 · s-1
versus 0.179 nmol · L-1 ·
s-1;
P=0.001). An identical pattern
was found in the case of prethrombin 2 and factor 1.2
generations (data not shown). There was no relationship between
simvastatin-induced reductions in thrombin B-chain
generation and reductions in TC
(Figure 2A) or LDL-cholesterol
(Figure 2B).
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) and after (•) simvastatin treatment are expressed as means±SEM.
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Prothrombin concentration decreased to 10% to 20% of the
initial value (1.36±0.07 µmol/L) by the last 30-s interval.
Prothrombin consumption was delayed by 60 s after
simvastatin administration. The rate of prothrombin
disappearance from blood after simvastatin administration
was decreased by 16.2±2.1%
(P=0.004; data not
shown).
Factor V/Va
Simvastatin treatment led to a delay (30 to
60 s) in the appearance of both factor Va heavy chain
(Mr=105 000) and factor Va light chain
(Mr=74 000), as illustrated in
Figure 3A (lanes 1 to 9B versus lanes 1 to 7A). Generation
of factor Va heavy chain after treatment was slower by almost
29.7±3.1% (P=0.007), and that
of factor Va light chain was 18.9±1.2% slower
(P=0.02), as depicted in
Figure 3B. After simvastatin treatment, factor
Va heavy chain and light chain concentrations in the last sample
(Figure 3A, lane 9B) were 2.9±0.12 nmol/L and 2.7±0.13
nmol/L, respectively, whereas before simvastatin, a mean
value for factor Va heavy chain was 4.2±0.18 nmol/L and factor Va
light chain 3.8±0.15 nmol/L. Overall, these results suggest that
production of the light chain is the limiting step in factor Va
generation in bleeding-time blood. Factor V
(Mr=330 000) before treatment disappeared
slowly in the first 5 minutes of bleeding with 70% to 80% of the
initial factor V concentration still present at the end of bleeding
(data not shown). These values are consistent with the levels
of factor Va heavy chain and light chain seen assuming a standard
plasma concentration of factor V of 20 nmol/L (20% of factor Va heavy
chain=4 nmol/L). Simvastatin depressed the rate of removal
of factor V from blood by 26.3±2.2%
(P=0.037). The rate of factor
Va generation was not related to the cholesterol-lowering
action of simvastatin.
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) and after (
) simvastatin treatment, are expressed as means±SEM. C, Immunoblot analyses of the product of FVa heavy chain cleavage by APC (30kDa; residues 307 to 506) in the fluid phase of nonreduced blood samples from a typical patient. A wells are blood samples before simvastatin treatment; B wells are posttreatment samples. D, Immunoblot analyses of FVa heavy chain (top band) with the 97-kDa fragment of this chain (bottom band) in bleeding-time blood. A wells are blood samples before simvastatin treatment; B wells are posttreatment samples.
Factor Va Inactivation
The characteristic fragments of factor Va heavy chain
produced by APC were visualized by using monoclonal antibodies. The
terminal APC degradation product of factor Va heavy chain
(Mr=30 000), formed as a result of cleavages at
Arg 506 and Arg 306,13
migrated identically with a factor Va inactivation product standard
(Figure 3C
) produced in bleeding-time blood. This fragment
was generated more rapidly (by 90 s) after simvastatin
treatment
(Figure 3C).
On reduced gels, a 97-kDa fragment of factor Va heavy chain
was found both before
(Figure 3D, lanes 1A to 7A) and after simvastatin
treatment
(Figure 3D, lanes 1B to 7B). A fragment of identical
mobility was observed by Hockin et
al21 in experiments in which
factor Va was incubated with thrombin in the presence of cultured human
umbilical vein endothelial cells. This product is
the result of an endothelial cell–dependent thrombin
inactivation of factor Va by cleavage at Arg 643. As with the factor Va
heavy chain, the level of the 97-kDa fragment increased over time.
Simvastatin treatment enhanced this factor Va inactivation
mechanism. The rate of factor Va inactivation was unrelated to the
simvastatin-induced reduction in TC or
LDL-C.
Factor XIII/Factor XIIIa
Before treatment, factor XIII activation was complete
at 20 s
(Figure 4, lane 4A). In simvastatin-treated
patients, this thrombin-dependent reaction was delayed by 60 s
(Figure 4 1B to 9B). Densitometry on immunoblots
showed that, after simvastatin treatment, the rate of the
disappearance of factor XIII was depressed by 19.8±1.3%
(P=0.001), whereas the rate of
factor XIIIa formation was accelerated by 20.6±2%
(P=0.03). There were no
correlations between the rate of factor XIII activation and the
hypolipemic effects of simvastatin.
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Fibrinogen
At baseline, depletion of fibrinogen from solution was
complete after 150 s. After the administration of the drug, complete
fibrinogen consumption occurred 60 s later and at a much slower
rate (72.2±3%; P=0.002) when
compared with baseline values (data not shown). Cholesterol
levels showed no correlation with the rate of fibrinogen
consumption.
Fibrinopeptides
Figure 5 represents a high-performance
liquid chromatography (HPLC) elution profile of the
fibrinopeptides isolated from the fluid phase of blood
of one of the patients and then identified by MALDI-TOF MS (data not
shown). All 3 forms of FPA, desAla FPA (an
NH2-terminal truncated form), P-FPA
(phosphorylated at Ser 3), and full length FPA and FPB
were seen, but des-Arg FPB (COOH-terminal cleavage) was not.
Simvastatin treatment did not alter the retention times of
the FPA and FPB generated; however, both FPA and FPB levels were
significantly depressed. Cumulative experiments showed that the mean
FPA concentration was decreased 25%, from 4.2±0.21 µmol/L to
3.1±0.16 µmol/L (P=0.02),
whereas FPB levels fell from 0.8 µmol/L to levels below the detection
limit. Two unidentified peaks labeled I and II
(Figure 5) were detected. Peak I increased after
simvastatin treatment while peak II decreased. The
identification of these peaks is currently in
process.
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Our results indicate that simvastatin treatment leads to multiple antithrombotic effects at sites of microvascular injury. In CAD patients with TC between 200 and 250 mg/dL, 3 months of simvastatin treatment was associated with a significant delay in and attenuation of the activation of prothrombin, factor V, factor XIII, and fibrinogen. The depressed factor V and factor XIII activation and thrombin-mediated fibrinogen cleavage induced by simvastatin are presumably the consequence of decreased prothrombin activation. Our data provide valuable insights into mechanisms that underlay antithrombotic actions of statins.
The flowing blood model used here can be compared with the TF-initiated coagulation model with nonanticoagulated whole blood, in which the intrinsic pathway is blocked by corn trypsin inhibitor. In the latter system,13 blood clots are formed at constant composition, whereas in the flowing blood system, new reactants are provided continuously to the wound site. Because increased flow rates can falsely lower concentrations of any product, total yield in each interval was calculated, revealing similar simvastatin-induced differences compared with those based on concentrations (data not shown). Comparisons are possible because the same primary antibodies used here for Western blots were also used by Rand et al.13 The increased rates of the reactions in the present model most probably are a consequence of increased levels of TF after vascular injury.22 It might be speculated that the attachment of fibrinogen and prothrombin to exposed subendothelial compounds also contributes to a rapid depletion of these coagulation factors from the pretreatment bleeding-time blood.23
We demonstrated significant reductions in FPA and FPB levels in CAD patients with borderline high hypercholesterolemia. This indicates that both thrombin-mediated cleavages in the fibrinogen molecule are impaired by simvastatin. Hence, fibrin formation is also impaired. In a model of nonanticoagulated whole blood, the complete release of FPA and activation of factor XIII occurred within 5 minutes.20 In the present model, these events occurred within 2 minutes. The unidentified species (I and II) detected by HPLC are suspected to be fibrinogen-related cleavage products resulting from the correlation with FPA and FPB.
Prolongation of the lag phase in -thrombin B-chain
generation in bleeding-time blood also indicates that
simvastatin may diminish TF expression/activity. The
duration of the lag phase is determined by concentrations of the
complex TF-factor VIIa and the tissue factor pathway
inhibitor.24
Levels of prothrombin and
AT-III,25 which
significantly influence thrombin generation, remained within the normal
range (50% to 150%) during simvastatin treatment and,
therefore, cannot explain its antithrombotic effects reported here.
Because TF expression is also regulated by TF pathway
inhibitor, it will become important to test the influence
of simvastatin on this anticoagulant.
The present study provides the first evidence for the formation of the 97 000 fragment (residues 1 to 643) of factor Va heavy chain in vivo, which is believed to be the product of thrombin action on factor Va, expressed in the presence of platelets26 and endothelial cells.21 Amounts of this product in bleeding-time blood increased after simvastatin administration, although thrombin concentrations were reduced. Therefore, cleavage of factor Va heavy chain at position 643 may not be catalyzed exclusively by thrombin.
In the microvasculature, in which thrombomodulin concentrations are presumed to be high relative to the blood volume, the appearance of factor Va degradation products occurred much faster than during clotting of the whole blood.13 A novel finding is that simvastatin induces increased rates of factor Va inactivation by APC, which suggests that the drug modulates the anticoagulant protein C pathway through increased expression of thrombomodulin or its activity. It is also possible that simvastatin affects the amount of active thrombomodulin released in loco from platelets.27
Our data provide evidence that the antithrombotic actions of statins are not related to their cholesterol-lowering effects. A possible mechanism by which simvastatin affects coagulation is through the inhibition of the synthesis of isoprenoids such as farnesyl and geranylgeranyl pyrophosphates, which are substrates for posttranslational modification and isoprenylation of numerous intracellular proteins.11 Suppression of isoprenoid production by simvastatin may lead to decreased expression of TF in the endothelium and/or subendothelium, although such an effect of statins was found only in monocytes and macrophages.11 12 Fenton et al28 put forward a hypothesis that decreased TF expression, combined with the downregulation in cell signaling after thrombin activation of protease activated receptor-1, may explain antithrombotic properties of HMG-CoA reductase inhibitors.
In conclusion, we present evidence for impaired activation of prothrombin, factor V, factor XIII, and enhanced factor Va inactivation by APC and impaired fibrinogen proteolysis after 3 months of simvastatin treatment in CAD patients with borderline-high hypercholesterolemia. Such a concerted influence of simvastatin on the clotting cascade seems to be independent of its lipid-lowering action and may be the result of depressed isoprenoid production. It may partly explain the early clinical benefits offered by simvastatin treatment to CAD patients.
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Acknowledgments |
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Supported by NIH grant HL-46703 to Dr Mann, NIH training grant T32 HL-07594 to Drs Brummel and Mann, and a Fulbright Fellowship to Dr Undas. We would like to thank Jed Pauls and Wojciech Sydor for their excellent technical assistance and Ted Foss for writing the HPLC Labview software that was used to quantitate the peptides.
Received October 3, 2000; revision received February 2, 2001; accepted February 15, 2001.
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 A. Undas, K. Szuldrzynski, K. E. Brummel-Ziedins, W. Tracz, K. Zmudka, and K. G. Mann Systemic blood coagulation activation in acute coronary syndromes Blood, February 26, 2009; 113(9): 2070 - 2078. [Abstract] [Full Text] [PDF]
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 N. Isma, J. Barani, I. Mattiasson, B. Lindblad, and A. Gottsater Lipid-Lowering Therapy is Related to Inflammatory Markers and 3-Year Mortality in Patients With Critical Limb Ischemia Angiology, October 1, 2008; 59(5): 542 - 548. [Abstract] [PDF]
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 A. Undas, I. Wiek, E. Stepien, K. Zmudka, and W. Tracz Hyperglycemia Is Associated With Enhanced Thrombin Formation, Platelet Activation, and Fibrin Clot Resistance to Lysis in Patients With Acute Coronary Syndrome Diabetes Care, August 1, 2008; 31(8): 1590 - 1595. [Abstract] [Full Text] [PDF]
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 M. Rodriguez-Yanez, J. Agulla, R. Rodriguez-Gonzalez, T. Sobrino, and J. Castillo Review: Statins and stroke Therapeutic Advances in Cardiovascular Disease, June 1, 2008; 2(3): 157 - 166. [Abstract] [PDF]
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 D. D. Waters, J. C. LaRosa, P. Barter, J.-C. Fruchart, A. M. Gotto Jr, R. Carter, A. Breazna, J. J.P. Kastelein, and S. M. Grundy Effects of High-Dose Atorvastatin on Cerebrovascular Events in Patients With Stable Coronary Disease in the TNT (Treating to New Targets) Study J. Am. Coll. Cardiol., November 7, 2006; 48(9): 1793 - 1799. [Abstract] [Full Text] [PDF]
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 J. D. Douketis, K. Arneklev, S. Z. Goldhaber, J. Spandorfer, F. Halperin, and J. Horrow Comparison of Bleeding in Patients With Nonvalvular Atrial Fibrillation Treated With Ximelagatran or Warfarin: Assessment of Incidence, Case-Fatality Rate, Time Course and Sites of Bleeding, and Risk Factors for Bleeding. Arch Intern Med, April 24, 2006; 166(8): 853 - 859. [Abstract] [Full Text] [PDF]
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 C. Lopez-Pedrera, P Buendia, M A Aguirre, F Velasco, and M J Cuadrado Antiphospholipid syndrome and tissue factor: a thrombotic couple Lupus, March 1, 2006; 15(3): 161 - 166. [Abstract] [PDF]
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P. Pignatelli, V. Sanguigni, B. Buchetti, L. Lenti, F. Violi, A. Undas, and K. G. Mann Early Anticoagulant Effect of Atorvastatin Arterioscler Thromb Vasc Biol, December 1, 2005; 25(12): e145 - e146. [Full Text] [PDF]
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K. K. Ray and C. P. Cannon The Potential Relevance of the Multiple Lipid-Independent (Pleiotropic) Effects of Statins in the Management of Acute Coronary Syndromes J. Am. Coll. Cardiol., October 18, 2005; 46(8): 1425 - 1433. [Abstract] [Full Text] [PDF]
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A. Undas, M. Celinska-Lowenhoff, K. E. Brummel-Ziedins, J. Brozek, A. Szczeklik, and K. G. Mann Simvastatin Given for 3 Days Can Inhibit Thrombin Generation and Activation of Factor V and Enhance Factor Va Inactivation in Hypercholesterolemic Patients Arterioscler Thromb Vasc Biol, July 1, 2005; 25(7): 1524 - 1525. [Full Text] [PDF]
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K. O'Neil-Callahan, G. Katsimaglis, M. R. Tepper, J. Ryan, C. Mosby, J. P.A. Ioannidis, and P. G. Danias Statins decrease perioperative cardiac complications in patients undergoing noncardiac vascular surgery: The Statins for Risk Reduction in Surgery (StaRRS) study J. Am. Coll. Cardiol., February 1, 2005; 45(3): 336 - 342. [Abstract] [Full Text] [PDF]
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A. Undas, K. E. Brummel-Ziedins, and K. G. Mann Statins and Blood Coagulation Arterioscler Thromb Vasc Biol, February 1, 2005; 25(2): 287 - 294. [Abstract] [Full Text] [PDF]
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 D Tousoulis, C Antoniades, E Bosinakou, M Kotsopoulou, C Tsioufis, C Tentolouris, A Trikas, C Pitsavos, and C Stefanadis Effects of atorvastatin on reactive hyperaemia and the thrombosis-fibrinolysis system in patients with heart failure Heart, January 1, 2005; 91(1): 27 - 31. [Abstract] [Full Text] [PDF]
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E. M. Scott, R. A.S. Ariens, and P. J. Grant Genetic and Environmental Determinants of Fibrin Structure and Function: Relevance to Clinical Disease Arterioscler Thromb Vasc Biol, September 1, 2004; 24(9): 1558 - 1566. [Abstract] [Full Text] [PDF]
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 E. M. Balk, J. Lau, L. C. Goudas, H. S. Jordan, B. Kupelnick, L. U. Kim, and R. H. Karas Effects of Statins on Nonlipid Serum Markers Associated with Cardiovascular Disease: A Systematic Review Ann Intern Med, October 21, 2003; 139(8): 670 - 682. [Abstract] [Full Text] [PDF]
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 G. Kadikoylu, V. Yukselen, I. Yavasoglu, and Z. Bolaman Hemostatic Effects of Atorvastatin Versus Simvastatin Ann. Pharmacother., April 1, 2003; 37(4): 478 - 484. [Abstract] [Full Text] [PDF]
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K. Masamura, K. Oida, H. Kanehara, J. Suzuki, S. Horie, H. Ishii, and I. Miyamori Pitavastatin-Induced Thrombomodulin Expression by Endothelial Cells Acts Via Inhibition of Small G Proteins of the Rho Family Arterioscler Thromb Vasc Biol, March 1, 2003; 23(3): 512 - 517. [Abstract] [Full Text] [PDF]
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A. Rezaie-Majd, G. W. Prager, R. A. Bucek, G. H. Schernthaner, T. Maca, H.-G. Kress, P. Valent, B. R. Binder, E. Minar, and M. Baghestanian Simvastatin Reduces the Expression of Adhesion Molecules in Circulating Monocytes From Hypercholesterolemic Patients Arterioscler Thromb Vasc Biol, March 1, 2003; 23(3): 397 - 403. [Abstract] [Full Text] [PDF]
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 W. C. Lau, L. A. Waskell, P. B. Watkins, C. J. Neer, K. Horowitz, A. S. Hopp, A. R. Tait, D. G.M. Carville, K. E. Guyer, and E. R. Bates Atorvastatin Reduces the Ability of Clopidogrel to Inhibit Platelet Aggregation: A New Drug-Drug Interaction Circulation, January 7, 2003; 107(1): 32 - 37. [Abstract] [Full Text] [PDF]
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K. G. Mann, S. Butenas, and K. Brummel The Dynamics of Thrombin Formation Arterioscler Thromb Vasc Biol, January 1, 2003; 23(1): 17 - 25. [Abstract] [Full Text] [PDF]
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A. Szczeklik, J. Musial, A. Undas, J. W. Eikelboom, J. Hirsh, J. I. Weitz, M. Johnston, Q. Yi, and S. Yusuf Reasons for Resistance to Aspirin in Cardiovascular Disease * Response Circulation, November 26, 2002; 106 (22): e181 - e182. [Full Text] [PDF]
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A. C. Sposito and M. J. Chapman Statin Therapy in Acute Coronary Syndromes: Mechanistic Insight Into Clinical Benefit Arterioscler Thromb Vasc Biol, October 1, 2002; 22(10): 1524 - 1534. [Abstract] [Full Text] [PDF]
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D. D. Waters, G. G. Schwartz, A. G. Olsson, A. Zeiher, M. F. Oliver, P. Ganz, M. Ezekowitz, B. R. Chaitman, S. J. Leslie, T. Stern, et al. Effects of Atorvastatin on Stroke in Patients With Unstable Angina or Non-Q-Wave Myocardial Infarction: A Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) Substudy Circulation, September 24, 2002; 106(13): 1690 - 1695. [Abstract] [Full Text] [PDF]
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A. Rezaie-Majd, T. Maca, R. A. Bucek, P. Valent, M. R. Muller, P. Husslein, A. Kashanipour, E. Minar, and M. Baghestanian Simvastatin Reduces Expression of Cytokines Interleukin-6, Interleukin-8, and Monocyte Chemoattractant Protein-1 in Circulating Monocytes From Hypercholesterolemic Patients Arterioscler Thromb Vasc Biol, July 1, 2002; 22(7): 1194 - 1199. [Abstract] [Full Text] [PDF]
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 L. K. Newby, A. Kristinsson, M. V. Bhapkar, P. E. Aylward, A. P. Dimas, W. W. Klein, D. K. McGuire, D. J. Moliterno, F. W. A. Verheugt, W. D. Weaver, et al. Early Statin Initiation and Outcomes in Patients With Acute Coronary Syndromes JAMA, June 19, 2002; 287(23): 3087 - 3095. [Abstract] [Full Text] [PDF]
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 G.F. Gensini and B. Dilaghi The unstable plaque Eur. Heart J. Suppl., March 1, 2002; 4(suppl_B): B22 - B27. [Abstract] [PDF]
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A. Undas, K. Brummel, J. Musial, K. G. Mann, and A. Szczeklik PlA2 Polymorphism of {beta}3 Integrins Is Associated With Enhanced Thrombin Generation and Impaired Antithrombotic Action of Aspirin at the Site of Microvascular Injury Circulation, November 27, 2001; 104(22): 2666 - 2672. [Abstract] [Full Text] [PDF]
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K. E. Brummel, S. G. Paradis, R. F. Branda, and K. G. Mann Oral Anticoagulation Thresholds Circulation, November 6, 2001; 104(19): 2311 - 2317. [Abstract] [Full Text] [PDF]
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 S. J Miller Emerging mechanisms for secondary cardioprotective effects of statins Cardiovasc Res, October 1, 2001; 52(1): 5 - 7. [Full Text] [PDF]
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