Research Paper
Subject Category: Cardiovascular and pulmonary pharmacology
British Journal of Pharmacology (2008) 153, 124–131; doi:10.1038/sj.bjp.0707543; published online 5 November 2007
The use of the Chandler loop to examine the interaction potential of NXY-059 on the thrombolytic properties of rtPA on human thrombi in vitro
N J Mutch1,5, N R Moore1, C Mattsson2, H Jonasson3, A R Green4,6 and N A Booth1
- 1Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
- 2AstraZeneca R&D Mölndal, Mölndal, Sweden
- 3AstraZeneca R&D Södertälje, Södertälje, Sweden
- 4AstraZeneca R&D Charnwood, Loughborough, UK
Correspondence: Dr AR Green, Institute of Neuroscience, School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK. E-mail: richard.green@nottingham.ac.uk
5Current address: Faculty of Biological Sciences, University of Leeds, Leeds, UK.
6Current address: Institute of Neuroscience, School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.
Received 22 August 2007; Accepted 28 August 2007; Published online 5 November 2007.
Abstract
Background and purpose:
Recombinant tissue-type plasminogen activator (rtPA) is the only globally approved treatment for acute ischaemic stroke. Other potential treatments might be administered with rtPA, making it important to discover whether compounds interfere with rtPA-induced lysis. We evaluated methods for examining the effect of the neuroprotectant NXY-059 on the lytic property of rtPA.
Experimental approach:
Plasma clot formation and lysis in the presence of rtPA and NXY-059 was measured as the change in plasma turbidity. The effect of NXY-059 on rtPA-induced lysis was similarly assessed on preformed clots. Lysis of the thrombus formed in a Chandler loop measured release of fluorescent-tagged fibrinogen that had been incorporated during thrombus formation. Thrombi were exposed to both rtPA and NXY-059 throughout lysis in the presence of 80% autologous plasma and the release of label during lysis was measured.
Key results:
Data interpretation is limited in the clot lysis experiments because either the rtPA was present during clot formation or the drug was added to a clot formed in static conditions. In contrast, thrombi were formed in dynamic flow conditions in the Chandler loop and the time course of lysis in plasma was examined. rtPA increased thrombolysis and the antifibrinolytic trans-4-(aminomethyl) cyclohexane carboxylic acid (AMCA) inhibited lysis. Lysis induced by rtPA was unaltered by NXY-059.
Conclusions and implications:
The Chandler loop method provides a reliable technique for examining the effect of compounds on rtPA-induced lysis in vitro and demonstrated that NXY-059 does not alter rtPA-induced lysis at clinically relevant concentrations of either drug.
Keywords:
recombinant tissue-type plasminogen activator, NXY-059, rtPA, thrombolysis, Chandler loop
Abbreviations:
AMCA, trans-4-(aminomethyl) cyclohexane carboxylic acid; ANOVA, analysis of variance; FITC, fluorescein isothiocyanate; NXY-059, disodium 2,4-disulphophenyl-N-tert-butylnitrone; rtPA, recombinant tissue-type plasminogen activator
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