(Stroke. 1997;28:830-836.)
© 1997 American Heart Association, Inc.
Articles |
Prevention of Carotid Artery Thrombosis by Oral Platelet GPIIb/IIIa Antagonist in Dogs
From the Cardiovascular Division, DuPont Merck Pharmaceutical Company, Wilmington, Del, and the University of Michigan, Ann Arbor (B.R.L.).
Correspondence to Shaker A. Mousa, PhD, DuPont Merck Pharmaceutical Company, Exp Station, E400/3456, Wilmington, DE 19880-0400.
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Background and Purpose Current antithrombotic therapy in acute ischemic stroke and myocardial infarction in which a combination of antiplatelet agents (aspirin) and anticoagulants (heparin) was used led to partial reduction of acute thrombotic complications. Recent advances in antiplatelet research led to the discovery of the platelet glycoprotein IIb/IIIa complex (GPIIb/IIIa), the final common pathway for platelet aggregation. The present study was undertaken to determine the oral antithrombotic efficacy of a potent and specific platelet GPIIb/IIIa antagonist, DMP728, in an electrically induced carotid artery thrombosis model in dogs. Based on the powerful antiplatelet efficacy of this mechanism in inhibiting all agonist-induced platelet aggregation as well as in inhibiting platelet procoagulant activity (thrombin generation and hence fibrin formation), an orally active antagonist for this integrin receptor might have potential benefits in stroke.
Methods Anesthetized dogs were instrumented for monitoring of arterial blood pressure, heart rate, and carotid artery flow velocity. Animals were treated with saline or DMP728 (0.1 to 1.0 mg/kg PO). Thrombus formation (platelet-rich aggregate with fibrous coating and a few erythrocytes) by anodal electrolytic stimulation (300 µA) to the intimal surface of the right carotid artery was initiated 120 minutes after oral DMP728 administration and continued for 180 minutes. Whole blood cell counts, ex vivo platelet aggregation, and template bleeding time were determined at different time points throughout the study.
Results DMP728 administered at 0.1 to 1.0 mg/kg PO exhibited dose-dependent antithrombotic efficacy in this model. DMP728 was shown to be significantly effective in inhibiting ex vivo platelet aggregation and in inhibiting thrombosis at 0.3 to 1.0 mg/kg PO. The antiplatelet, antithrombotic effects of DMP728 were demonstrated without any significant changes in the different hemodynamic or coagulation parameters. These data demonstrated the oral antithrombotic efficacy of DMP728 in dogs.
Conclusions Platelet GPIIb/IIIa blockade with an orally active antagonist was shown to be safe and effective in the prevention of carotid artery occlusive thrombosis.
Key Words: antiplatelet agents • antithrombotic therapy • carotid arteries • thrombosis • dogs
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Platelet activation and the resulting aggregation have been shown to be associated with various pathological conditions, including cardiovascular and cerebrovascular thromboembolic disorders such as unstable angina, myocardial infarction, transient ischemic attack, stroke, and atherosclerosis.1 2 3 4 5 6 The contribution of platelets to these disease processes stems from their ability to form aggregates or platelet thrombi as a consequence of arterial wall injury.2 4 Injury of blood vessel walls could occur either acutely or chronically by various pathophysiological processes. Platelets are then activated by a number of activators or agonists that are released from within platelets or from the injured arterial walls, with subsequent adherence, aggregation to the disrupted vessel surface, and resultant formation of an occlusive thrombus in the lumen of the vessel.7 8 9 10
Current antiplatelet drugs are mainly effective against one of the many platelet activators. These drugs include aspirin; ticlopidine; thromboxane A2 synthetase inhibitors or receptor antagonists; and hirudin.11 12 13 Hence, the potential clinical benefits of an agent that inhibits plate let activation in response to all of these agonists should represent a more efficacious therapeutic approach than the use of current platelet inhibitors, either alone or in combination. Additionally, a high incidence of coronary artery reocclusion after successful thrombolytic therapy is a persistent clinical problem.14 Thus, prevention of reocclusion with an adjunctive pharmacological agent is an area that is being actively pursued with different compounds, including anticoagulants, antiplatelet agents, and maintained infusion of thrombolytics.14 15 The beneficial effects of thrombolytic therapy for myocardial infarction are established, and the side effects are less serious than once expected. However, thrombolytic therapy with either recombinant tissue plasminogen activator or streptokinase is associated with reocclusion rates of 5% to 25%. These percentages represent patients with concomitant aspirin and/or heparin administration. It is apparent that the ability of heparin and aspirin to prevent reocclusion after thrombolysis is limited. For this reason, this and other laboratories are searching for alternative oral antithrombotic strategies that may provide sustained reperfusion with minimum risk of hemorrhagic events.
Recently, the platelet glycoprotein IIb/IIIa complex (GPIIb/IIIa) has been identified as the final common pathway for all agonists.16 17 The binding of adhesive proteins such as fibrinogen to GPIIb/IIIa causes platelets to aggregate.17 18 The binding of fibrinogen is mediated in part by the arginine–glycine–aspartic acid (RGD) recognition sequence, which is common to the adhesive proteins that bind to GPIIb/IIIa receptors.16 17 18 The first platelet GPIIb/IIIa antagonists to be developed were monoclonal antibodies, such as the chimeric c7E3 (ReoPro).19 20 21 7E3 effectively inhibits platelet aggregation against all known platelet agonists in experimental animals as well as in patients.19 20 21 These antiplatelet effects of platelet GPIIb/IIIa antagonists such as c7E3 (ReoPro) led to significant clinical benefits in reducing acute coronary ischemic syndromes.22 Platelet GPIIb/IIIa antagonists have been shown to reduce procoagulant activity on the platelet surface, with an attenuation of thrombin generation and hence a reduction of fibrin formation in addition to the major effect of inhibiting platelet aggregation.23 Considering these factors, we proposed that an oral platelet GPIIb/IIIa antagonist might have potential utility in ischemic stroke. Because of certain limitations in the use of monoclonal antibodies as therapeutic agents, including immunogenicity and lack of oral activity, many groups have concentrated on developing small-molecule intravenously and orally active platelet GPIIb/IIIa antagonists.24 25 26
DMP728 demonstrated antithrombotic efficacy in various animal models of occlusive (peripheral and coronary arteries) and unstable thrombosis associated with waves of cyclic flow reduction (coronary artery) in dogs after its intravenous administration.27 The present study examines the oral antithrombotic effectiveness of DMP728 in an occlusive carotid artery thrombosis model in dogs.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Reagents
ADP and other reagents used in these studies were obtained from Sigma Chemical Co. DMP728 (cyclic [D-2-aminobutyryl-N2-methyl-L-argininyl-glycyl-L-aspartyl-3-aminomethyl benzoic acid] methanesulfonic acid) and RGD were synthesized at the DuPont Merck Pharmaceutical Co.
Model of Carotid Artery Occlusion
A model of electrolytic injury–induced carotid artery occlusive
thrombus formation was used.28 This experimental procedure
results in the formation of a platelet-rich intravascular thrombus
along with a few erythrocytes and a rough fibrous coating at the site
of an electrolytically induced endothelial lesion in
proximity to distal arterial stenosis. The carotid
artery response to electrolytic injury is similar to that observed in
the canine coronary artery. In the case of evaluating
intravenous antithrombotic efficacy of a test agent, we can
use the right (control) and left (intravenous treatment)
carotid arteries or vice versa to establish time to occlusion (minutes)
and thrombus weight (milligrams) before and after the
intravenous administration of a test agent (ie, the same
animal can serve as control). In our present investigation of oral
antithrombotic efficacy, we used separate control and treated
animals.
Surgical Preparation
Male, mongrel dogs (weight, 15 to 17 kg) were
anesthetized (n=12 for control, n=5 to 6 for the different oral
dose levels of DMP728) with sodium pentobarbital (30 mg/kg IV),
intubated, and allowed to breathe room air. Both common carotid
arteries and the right internal jugular vein were exposed. A catheter
was inserted into the jugular vein for blood sampling and
administration of the test drug. Arterial blood pressure
was monitored from the cannulated femoral artery with the use of a
blood pressure transducer (Cardiovascular Products,
Gould Inc). Standard limb lead II of the
electrocardiogram was recorded continuously. A
Doppler flow probe (model 100, Triton Technology) was placed on
each common carotid artery proximal to both the point of insertion of
the intra-arterial electrode and the mechanical
constrictor. The mechanical constrictor was constructed of stainless
steel in a C shape with a
polytetrafluoroethylene (Teflon brand)
screw (2-mm diameter) that could be adjusted to control vessel
circumference and produce a regional stenosis. The constrictor
was adjusted until the pulsatile flow pattern was reduced by 50%
without altering the mean blood flow. Blood flow in the carotid vessels
was monitored continuously.
Electrolytic injury to the intimal surface of each carotid vessel was accomplished with the use of an intravascular electrode composed of a Teflon-insulated, silver-coated copper wire. Penetration of the vessel wall by the electrode was facilitated by attaching the tip of a 25-gauge hypodermic needle to the uninsulated part of the electrode. Each intra-arterial electrode was connected to the positive pole (anode) of a dual-channel stimulator (Grass S88 stimulator and Grass Constant Current Unit, model CCU1A, Grass Instrument Co). The cathode was connected to a distant subcutaneous site. The current delivered to each vessel was monitored continuously on a separate ammeter and maintained at 300 µA. The anodal electrode was positioned to have the uninsulated portion in intimate contact with the endothelial surface of the vessel. Positioning of the electrodes in each of the carotid arteries was confirmed by visual inspection at the end of each experiment.
Protocol: Prevention of Thrombus Formation
The anodal current was applied for a maximum period of 3 hours
or was terminated 30 minutes after flood flow in the involved vessel
remained stable at zero flow velocity to verify the formation of a
stable occlusive thrombus. Arterial thrombosis and
thrombotic occlusion occurred in response to intimal damage, after
which the vessel segment was ligated, both proximal and distal to the
point of injury, and removed without disturbing the intravascular
thrombus. The vessel segment was opened along its length, and the
intact thrombus mass was lifted off the intimal surface of the vessel.
The weight of the thrombus mass was determined with an analytical
balance. Thrombus was formed only at the injury site. Scanning electron
micrographic studies demonstrated the presence of a rough surface with
fibrous coating containing platelets and a few
erythrocytes.28
Fig 1
shows the protocol used for studies that required
oral drug administration. DMP728 at 0.1 to 1.0 mg/kg was administered
in a gelatin capsule followed by 10 mL saline. Dogs were
anesthetized 120 minutes after ingestion of the capsule, the
right carotid artery was instrumented, and electrolytic
arterial injury was initiated as discussed in the text.
|
Hematologic Measurements
Blood was withdrawn for platelet studies from the jugular
cannula into a plastic syringe containing 3.2% sodium citrate as the
anticoagulant (1:10 citrate to blood [vol/vol]). Blood was taken for
platelet aggregation and whole blood cell counts at baseline, 60
minutes, and 240 minutes after the administration of DMP728. The
platelet count was determined with an H-10 cell counter (Texas
International Laboratories, Inc). Platelet-rich plasma (PRP), the
supernatant present after centrifugation of
anticoagulated whole blood at 1000 rpm for 5 minutes (140g),
was diluted with platelet-poor plasma (PPP) to achieve a
platelet count of 200 000/mm3. PPP was prepared after
the PRP was removed by centrifuging the remaining blood at
12 000g for 10 minutes and discarding the bottom cellular
layer. Ex vivo platelet aggregation was measured by established
spectrophotometric methods with a four-channel aggregometer (BioData
PAP-4, BioData Corp) by recording the increase in light
transmission through a stirred suspension of PRP maintained at
37°C.27 Aggregation was induced with ADP (100
µmol/L). Values were expressed as percentages of aggregation,
representing the percentage of light transmission
standardized to PRP and PPP samples yielding 0% and 100% light
transmission, respectively.
Bleeding times were measured in anesthetized dogs with a Simplate device by making incisions on the tongue and blotting the wound with filter paper at 30-second intervals until blood was no longer transferred to the filter paper.
Inclusion Criteria
Animals that were included in the final protocol satisfied the
following preestablished criteria: (1) a circulating platelet count
of not less than 100 000/mm3; (2) demonstrated ability of
platelets to aggregate in response to arachidonic
acid before administration of DMP728; (3) thrombotic occlusion of the
right carotid artery (control vessel) within 4 hours from the onset of
vessel wall injury with a 300-µA direct anodal current; and (4)
absence of heart worms on final postmortem examination.
Statistical Analysis
The data are expressed as mean±SEM. Ex vivo platelet
aggregation in response to ADP was assessed before and after oral
DMP728. The data were analyzed by either paired or group
analysis with the use of Student's t test when
applicable; differences were considered significant at
P<.05.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Prevention of Thrombus Formation
A total of 28 dogs (n=12 and n=16 for control and oral DMP728 dose level groups, respectively) were entered into this arm of the study, and DMP728 (0.1 to 1.0 mg/kg PO) was administered as discussed previously in the protocol. Blood pressure and heart rate were not different across groups at baseline, and the administration of DMP728 had no effect on these parameters at either dose tested (data not shown). The effects of DMP728 administration on the incidence of carotid artery occlusion are shown in Table 1
.
Antagonism of the GPIIb/IIIa receptor with DMP728 resulted in a
significant reduction in the incidence of occlusion compared with the
control group. A steep dose-response effect with DMP728 was evident,
with maximal antithrombotic efficacy at doses of 0.3 to 1.0 mg/kg PO
and minimal efficacy at 0.1 mg/kg PO (Table 1). Maximal antithrombotic
efficacy was demonstrated at 0.3 mg/kg PO (Table 1). The effect of
DMP728 on carotid artery blood flow velocity is represented
in Fig 2. The graphs represent carotid artery
blood flow velocity measured at baseline and again at either 180 or 240
minutes after electrolytic vessel wall injury for control and treated
groups. The control vessels proceeded to occlusion within the
180-minute time period. Administration of DMP728 in increasing amounts
attenuated the decrease in carotid blood flow velocity and resulted in
fewer vessels proceeding to complete occlusion. The time to occlusion
is shown in Table 1. Vessels that did not occlude were assigned a value
of 240 minutes for comparison. A significant prolongation of the time
to thrombotic occlusion was seen in all groups receiving DMP728.
Thrombus weight was reduced in all treatment groups except those dogs
that received DMP728 at 0.1 mg/kg PO (Table 1).
|
|
Ex vivo platelet aggregation was measured before and at 60, 120,
240, 300, and 360 minutes after DMP728. The results are shown in Table 2. Dogs that received the 0.3- to 1.0-mg/kg doses
demonstrated significant inhibition of platelet aggregation,
whereas those in the low-dose group showed little inhibition of
aggregation to ADP. DMP728 extended template bleeding time twice in the
dogs treated with 0.1 mg/kg PO and seven times baseline in the dogs
treated with 1.0 mg/kg PO (Fig 3). The effects of oral
DMP728 on whole blood cell counts in dogs are presented in
Table 3. Red cell counts, platelet counts, and
hematocrit were unchanged by the treatment, and all fell within normal
ranges for canine whole blood values. No changes were seen in either
group at any of the times measured.
|
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
It is well recognized that platelet GPIIb/IIIa, through its binding to circulating fibrinogen, is the final common pathway for all agonist-induced platelet aggregate formation.16 17 18 The binding of fibrinogen is mediated in part by the RGD recognition sequence, which is common to other adhesive proteins that bind to GPIIb/IIIa receptors or other integrins.17 Several RGD-containing peptides as well as the 7E3 monoclonal antibody against platelet GPIIb/IIIa have been shown to block fibrinogen binding and prevent the formation of platelet thrombi.19 20 21 22 However, certain problems are associated with the use of peptides as antithrombotic agents, including their short survival time or metabolic instability in the circulation, which might be advantageous in permitting rapid reversal of the antihemostatic effect in bleeding but clearly poses a burden in terms of quantity needed and the lack of oral activity. This certainly is not the case with DMP728, which is metabolically stable and very effective at extremely low doses.
In contrast to other antiplatelet agents such as aspirin, ticlopidine, and hirudin, which are effective mainly against a single agonist (arachidonic acid, ADP, or thrombin, respectively) in inhibiting platelet aggregation in human PRP, DMP728 demonstrated high affinity and similar potency in inhibiting platelet aggregation regardless of the agonist used.25 28 Additionally, DMP728 demonstrated a high degree of selectivity toward the platelet GPIIb/IIIa receptors compared with the closely related vitronectin receptors on endothelial cells or other adhesion receptors on platelets or leukocytes.29 Intravenous administration of DMP728 in anesthetized dogs produced a dose-dependent inhibition of ex vivo platelet aggregation. DMP728 demonstrated oral bioavailability in various species (10% to 15%) and reversible effects on bleeding time prolongation while maintaining maximal inhibition of platelet aggregation.27 30 The antiplatelet effects of DMP728 were shown at extremely low doses.
It has also been shown that the antagonism of the platelet GPIIb/IIIa receptors in anesthetized dogs by DMP728 had no effect on any of the different hemodynamic parameters (data not shown) or platelet counts over the wide range of doses administered. There was no observed spontaneous bleeding at any sites other than the confined sites of bleeding time measurements. DMP728 demonstrated no significant effects on blood pressure, heart rate, intrinsic or extrinsic coagulation pathways, white cell count, red cell count, platelet count, hemoglobin, or hematocrit. Bleeding time was prolonged and ex vivo platelet aggregation was inhibited in a dose-dependent fashion after intravenous and oral administration of DMP728. Carotid artery thrombotic occlusion in response to electrolytic vessel wall injury was prevented by oral DMP728 in a dose-dependent manner. DMP728 was effective in reducing primary thrombus weight in response to electrolytic vessel wall injury.
The effects of the direct thrombin inhibitor hirudin and the GPIIb/IIIa antagonists 7E3 and DMP728 on the prevention of thrombosis and rethrombosis after coronary thrombolysis in a chronic canine model have been recently documented.30 31 In contrast to the GPIIb-IIIa antagonists, which were very effective in preventing thrombosis and rethrombosis, the direct thrombin inhibitor provided little improvement in the incidence of reocclusion and mortality in the same model.31 In this study, animals treated with hirudin exhibited rebound reocclusion after the discontinuation of the infusion. A similar phenomenon with heparin therapy has recently been reported, in which a significant number of patients experienced reactivation of unstable angina episodes, suggesting evidence of rebound coagulation with thrombin inhibitors in unstable angina.32 Oscillation flow or cyclic flow variations were also found to occur in hirudin-treated animals but not in the 7E3- or DMP728-treated groups. These variations in flow, which occur clinically after administration of tissue plasminogen activator, may contribute to myocardial damage, persistent reocclusion, or arrhythmic events. Cyclic flow variations can be intensified under stressful conditions associated with catecholamine release. Thus, suppressing cyclic flow variations is important in achieving vessel wall patency. In the animal model of Folts, different GPIIb/IIIa antagonists demonstrated maximal efficacy in inhibiting ex vivo platelet aggregation, in totally preventing cyclic flow reduction, and in maintaining coronary flow and coronary arterial patency.33 This suggests the potential of GPIIb/IIIa antagonists in unstable angina. In contrast, aspirin (0.5 to 5.0 mg/kg IV) is marginally effective in this model and ineffective against epinephrine-induced cyclic flow reduction. Accordingly, we would anticipate that GPIIb/IIIa antagonists might be more effective than aspirin in unstable angina. Additionally, it has been demonstrated that intravenous treatment with chimeric 7E3 prevents electrolytically induced carotid artery thrombosis in the cynomolgus monkey.34 In contrast, treatment with heparin, aspirin, or their combination failed to protect against occlusive thrombus formation in the same model.34 More recently, the inhibitory effects of an anti-PECAM (platelet–endothelial cell adhesion molecule) antibody on platelet adhesion/aggregation at sites of minor endothelial damage in brain arterioles in mice were assessed.35 This suggests another level of intervention in the prevention of thromboembolic disorders.
These results demonstrate that DMP728 is an orally active, specific IIb/IIIa receptor antagonist that may prove to be clinically useful as a potent antiplatelet antithrombotic agent in carotid artery thromboembolic disorders.
Received June 24, 1996; revision received December 10, 1996; accepted January 17, 1997.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
1. Hirsh PD, Hillis LD, Campbell WB, Firth BG, Willerson JT. Release of prostaglandins and thromboxane into the coronary circulation in patients with ischemic heart disease. N Engl J Med. 1981;304:685-691. [Abstract]
2. Rubenstein MD, Wall RT, Baim DS, Harrison DC. Platelet activation in clinical coronary artery disease and spasm. Am Heart J. 1981;102:363-367. [Medline] [Order article via Infotrieve]
3. Smitherman TC, Milam M, Woo J, Willerson JT, Frenkel EP. Elevated beta thromboglobulin in peripheral venous blood of patients with acute myocardial ischemia: direct evidence for enhanced platelet reactivity in vivo. Am J Cardiol. 1981;48:395-402. [Medline] [Order article via Infotrieve]
4. Fitzgerald DJ, Roy L, Catella F, Fitzgerald GA. Platelet activation in unstable coronary disease. N Engl J Med. 1986;315:983-989. [Abstract]
5. Fuster V, Steele PM, Chesebro JH. Role of platelets and thrombosis in coronary atherosclerotic disease and sudden death. J Am Coll Cardiol. 1985;5:175B-184B.
6.
Travis J. Biotech gets a grip on cell adhesion:
frontier in biotechnology. Science. 1993;260:906-908.
7.
Willerson JT, Golino P, Eidt J, Campbell WB, Buja
LM. Specific platelet mediators and unstable
coronary artery lesions: experimental evidence and potential
clinical implications. Circulation. 1989;80:198-205.
8.
Davies MJ, Thomas AC. Plaque fissuring: the
cause of acute myocardial infarction, sudden ischemic death,
and crescendo angina. Br Heart J. 1985;53:363-373.
9. Hamm CW, Bliefield W, Kupper W, Lorenz RL, Weber PC, Wober W. Biochemical evidence of platelet activation in patients with persistent unstable angina. J Am Coll Cardiol. 1987;10:998-1004. [Abstract]
10. Ashby B, Daniel JL, Smith JB. Mechanisms of platelet activation and inhibition. Hematol Oncol Clin North Am. 1990;4:1-26. [Medline] [Order article via Infotrieve]
11. Saltiel E, Ward A. Ticlopidine: a review of its pharmacodynamic and pharmacokinetic properties and therapeutic efficacy in platelet-dependent disease states. Drugs. 1987;34:222-262. [Medline] [Order article via Infotrieve]
12.
Golino P, Ashton JH, Glas-Greenwalt P, McNatt J, Buja
LM, Willerson JT. Mediation of reocclusion by
thromboxane A2 and serotonin after
thrombolysis with t-PA in a canine preparation of
coronary thrombosis. Circulation. 1988;77:678-684.
13. Walenga JM, Pifarra R, Fareed J. Recombinant hirudin as an antithrombotic agent. Drugs of Future.. 1990;15:267-270.
14.
Chesebro JH, Knatterud G, Roberts R, Borer J, Cohen LS,
Dalen J, Dodge HT, Francis CK, Hillis D, Ludbrook P, Markis JE, Mueller
H, Passamani ER, Powers ER, Rao AK, Robertson T, Ross A, Ryan TJ, Sobel
BE, Willerson J, Williams DO, Zaret BL, Braunwald E.
Thrombolysis in Myocardial Infarction (TIMI) Trial, phase
I: a comparison between intravenous tissue
plasminogen activator and
intravenous streptokinase. Circulation. 1987;76:142-154.
15.
John JA, Gold HK, Leinbach RC, Yasuda T, Gimple LW,
Werner W, Finkelstein D, Newell J, Ziskind AA, Collen D.
Prevention of coronary artery reocclusion and reduction in late
coronary artery stenosis after
thrombolytic therapy in patients with acute myocardial
infarction. Circulation. 1988;78:546-556.
16.
Pytela R, Pierschbacher MS, Ginsberg MH, Plow EF,
Ruoslahti E. Platelet membrane glycoprotein
IIb/IIIa: member of a family of RGD specific adhesion
receptors. Science. 1986;231:1559-1562.
17. Philips DR, Charo IF, Scarborough RM. GPIIb/IIIa: the responsive integrin. Cell. 1991;65:359-362. [Medline] [Order article via Infotrieve]
18.
D'Souza SE, Ginsberg MH, Burke TA, Plow EF. The
ligand binding site of the platelet integrin receptor GPIIb-IIIa is
proximal to the second calcium binding domain of its 
subunit. J Biol Chem. 1990;265:3440-3446.
19. Yasuda T, Gold HK, Yaoita H, Leinbach RC, Guerrero JL, Jang IK, Holt R, Fallon JT, Collen D. Comparison effects of aspirin, a synthetic thrombin inhibitor and a monoclonal antiplatelet glycoprotein IIb/IIIa antibody on coronary artery reperfusion, reocclusion and bleeding with recombinant tissue-type plasminogen activator in a canine preparation. J Am Coll Cardiol.. 1990;16:714-722. [Abstract]
20.
Coller BS, Folts JD, Scudder LE, Smith SR.
Antithrombotic effect of a monoclonal antibody to the platelet
glycoprotein IIb/IIIa receptor in an experimental animal
model. Blood. 1986;68:783-786.
21. Gold HK, Gimple LW, Yasuda T, Leinbach RC, Werner W, Holt R, Jordon R, Berger H, Collen D, Coller BS. Pharmacodynamic study of F(ab')2 fragments of murine monoclonal antibody 7E3 directed against human platelet glycoprotein IIb/IIIa, in patient with unstable angina pectoris. J Clin Invest. 1990;86:651-659.
22. Mousa SA, Topol EJ. Recent advances in the development of platelet GPIIb/IIIa receptor antagonists. In: Holmes D, ed. Current Review of Interventional Cardiology. Philadelphia, Pa: Current Medicine; 1996:113-129.
23. Reverter JC, Beguin S, Kessels H, Hemker HC, Coller BS. Inhibition of platelet-mediated, tissue factor-induced thrombin generation by the mouse/human chimeric 7E3 antibody. J Clin Invest. 1996,98:863-874.
24. Peerlinck K, De Lepeleire I, Goldberg M, Farrell D, Barrett J, Hand E, Panebianco D, Deckmyn H, Vermylen J, Arnout J. MK383 (L-700,462), a selective nonpeptide platelet glycoprotein IIb/IIIa antagonist, is active in man. Circulation. 1993;88(4 pt 1):1512-1517.
25. Tcheng JE, Harrington RA, Kottke-Marchant K, Kleiman NS, Ellis SG, Kereiakes DJ, Mick MJ, Navetta FI, Smith JE, Worley SJ, Miller JA, Joseph DM, Sigmon KN, Kitt MM, du Mée CP, Califf RM, Topol EJ, for the IMPACT Investigators. Multicenter, randomized, double-blind, placebo-controlled trial of the platelet integrin glycoprotein IIb/IIIa blocker Integrelin in elective coronary intervention. Circulation. 1995,91:2151-2157.
26. Topol EJ. Novel antithrombotic approaches to coronary artery diseases. Am J Cardiol. 1995;75:27b-33b.
27.
Mousa SA, Bozarth JM, Forsythe MS, Jackson S, Leamy A,
Diemer M, Kapil R, Knabb R, Mayo M, De Grado WF, Pierce SK, Thoolen MJ,
Reilly TM. Antiplatelet and antithrombotic efficacy of
DMP728, a novel platelet GPIIb/IIIa antagonist.
Circulation. 1994;89:3-12.
28. Romson JL, Haack DW, Lucchesi BR. Electrical induction of coronary artery thrombosis in the ambulatory canine: a model for in vivo evaluation of antithrombotic agents. Thromb Res. 1980;17:841-853. [Medline] [Order article via Infotrieve]
29. Mousa SA, Bozarth JM, Forsythe MS, Lorelli W, Ramachandran N, Jackson S, De Grado W, Reilly TM. Antiplatelet efficacy and specificity of DMP728, a novel platelet GPIIb/IIIa receptor antagonist. Cardiology. 1993;83:374-382. [Medline] [Order article via Infotrieve]
30. Mousa SA, Reilly TM. Antiplatelet effects of direct acting thrombin inhibitors and platelet GPIIb-IIIa antagonists: comparative analysis. In: Gallo LL, ed. Cardiovascular Disease 2. New York, NY: Plenum Press; 1995:255-268.
31. Rote W, Mu D-X, Bates ER, Nedelman MA, Lucchesi BR. Prevention of rethrombosis after coronary thrombolysis in a chronic canine model, II: adjunctive therapy with r-hirudin. J Cardiovasc Pharmacol. 1993;23:203-211.
32. Gold HK, Torres FW, Garabedian HD, Werner W, Jang I. Evidence of a rebound coagulation phenomenon after cessation of a 4-hour infusion of a specific thrombin inhibitor in patients with unstable angina. J Am Coll Cardiol. 1993;21:1039-1047. [Abstract]
33. Mousa SA. Antiplatelet/antithrombotic effects of platelet GPIIb/IIIa receptor antagonists, thrombin inhibitors, and aspirin: comparative analysis. In: Zavoico G, Sussman C, Savage L, eds. Advances in Anticoagulant and Thrombolytic Therapies. Southborough, Mass: IBC Biomedical Library Series; 1996:1-19.
34. Rote WE, Nedelman MA, Mu D-X, Manley PJ, Weisman H, Cunningham MR, Lucchesi BR. Chimeric 7E3 prevents carotid artery thrombosis in cynomolgus monkeys. Stroke. 1994;25:1223-1233. [Abstract]
35.
Rosenblum WI, Nelson GH, Wormley B, Werner P, Wang J,
Shih CY. Role of platelet–endothelial cell
adhesion molecule (PECAM) in platelet adhesion/aggregation over
injured but not denuded endothelium in vivo and ex
vivo. Stroke. 1996;27:709-711.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||