Alternativmethodezumknock-out Modell in der Arterioskleroseforschung: Sascha Meyer dos Santos

Transcription

1 Alternativmethodezumknock-out Modell in der Arterioskleroseforschung: humane Arterien in flow-based adhesion assays Sascha Meyer dos Santos

2 Replacement, Reduction, Refinement aktueller denn je? Viewpoint from a basic scientist

3 Overview What are flow-based assays? Why bother with alternatives to animal experiments? What are the reactions during publishing a manuscript when using alternative approaches? Replacement, Reduction, Refinement aktueller denn je? Summary Surface-acoustic waves driven micro-fluidic coagulation assay: a new project

4 Impact factors hematology 2012

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6 flow-based adhesion assays

7 flow-based adhesion assays Biomedical Simulation Lab - "David Steinman, University of Toronto"

8 experimental setup Meyer dos Santos et al., Platelets 2010

9 experimental setup

10 experimental setup Meyer dos Santos et al., Platelets 2010

11 Superfamily transmembrane chemokines

12 Endothelial expressed fractalkine Meyer dos Santos et al., Blood 2011

13 review process 2010

14 review process > Switch of all proteins and AB to non-human reactivity -> value in regard to the application of the results to human disease -> ethical considerations

15 Overview of in vivo systems for generating transgenic platelets. Thijs T et al. Blood 2012;119: by American Society of Hematology

16 Human artery segments as adhesion matrix for en-face microscopy under flow Methods Molecular Biology 139, p71

17 Human artery segments as adhesion matrix for en-face microscopy under flow Methods Molecular Biology 139, p71

18 Human artery segments as adhesion matrix for en-face microscopy under flow

19 Human artery segments as adhesion matrix for en-face microscopy under flow

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25 Das Bildelement mit der Beziehungs-ID rid2 wurde in der Datei nicht gefunden.

26 Human artery segments as adhesion matrix

27 Human artery segments as adhesion matrix untreated anti-gpib alpha

28 review process 2010

29 review process 2010

30 review process 2010

31 review process 2010

32 In vivo significance of in vitro flow-based assays? What is happening in the intact vessel? Knock-out mouse experiments? Relevance for human pathophysiology?

33 In vivo significance of in vitro flow-based assays? What is happening in the intact vessel? Knock-out mouse experiments? Relevance for human pathophysiology? Is this the holy grail? Image from

34 In vivo significance of in vitro flow-based assays? What is happening in the intact vessel? Knock-out mouse experiments? Relevance for human pathophysiology? Is this the holy grail? Plaques develop in rodents not spontaneously, you need ApoE -/- or LDLR -/- knock-out Plaques do not rupture in rodents Platelet receptor expression and signaling differs substantially between rodents and primates

35 In vivo significance of in vitro flow-based assays? What is happening in the intact vessel? Knock-out mouse experiments? Relevance for human pathophysiology?

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37 Game changer?

38 review process 2013

39 In vivo significance of in vitro flow-based assays? What is happening in the intact vessel? Knock-out mouse experiments? Relevance for human pathophysiology? Is this the holy grail? Image from

40 In vivo significance of in vitro flow-based assays?

41 In vivo significance of in vitro flow-based assays?

42 In vivo significance of in vitro flow-based assays? Game changer? Increased acceptance of novel and innovative methods in the scientific community?

43 Replacement, Reduction, Refinement aktueller denn je? Viewpoint from a basic scientist

44 RRR aktueller denn je?

45 RRR aktueller denn je?

46 Do these results call into question all biomedical research on the mouse? Certainly not. There is little doubt that at the molecular level there are many congruencies between the species, and there are plenty of mouse mutants that phenotypically resemble their human counterparts. If one considers that the environments in which the mouse and human immune responses have evolved were (and are) quite different, it is conceivable that mouse models for immune conditions are particularly prone to diverge from those for the human. The work is nevertheless a challenge that should prompt a more critical examination of the mouse as a tool to study human disease. It is also a sobering reminder of what most thoughtful biologists already know: your biological conclusions are really only as good as the methods that get you there.

47 Do these results call into question all biomedical research on the mouse? Certainly not. There is little doubt that at the molecular level there are many congruencies between the species, and there are plenty of mouse mutants that phenotypically resemble their human counterparts. If one considers that the environments in which the mouse and human immune responses have evolved were (and are) quite different, it is conceivable that mouse models for immune conditions are particularly prone to diverge from those for the human. The work is nevertheless a challenge that should prompt a more critical examination of the mouse as a tool to study human disease. It is also a sobering reminder of what most thoughtful biologists already know: your biological conclusions are really only as good as the methods that get you there.

48 Do these results call into question all biomedical research on the mouse? Certainly not. There is little doubt that at the molecular level there are many congruencies between the species, and there are plenty of mouse mutants that phenotypically resemble their human counterparts. If one considers that the environments in which the mouse and human immune responses have evolved were (and are) quite different, it is conceivable that mouse models for immune conditions are particularly prone to diverge from those for the human. The work is nevertheless a challenge that should prompt a more critical examination of the mouse as a tool to study human disease. It is also a sobering reminder of what most thoughtful biologists already know: your biological conclusions are really only as good as the methods that get you there.

49 Strong points No animals required Completely human materials: no questionable transferability of mouse experiments to human disease / we are as close at human pathophysiology as possible No complicated approval of the local ethics committee: material is based on unused remains Cheap Results are fast at hand -> no breeding (knock-out) required Easy to use Weak points This is not in vivo No complex plaque is there -> limited to the initial stages of disease Limited supply (for HTS) Hard to control precise shear Starts to leak after extended perfusion times (5 20 min) Potential host-graft reaction (vwf-dependent adhesion )

50 Strong points No animals required Completely human materials: no questionable transferability of mouse experiments to human disease / we are as close at human pathophysiology as possible No complicated approval of the local ethics committee: material is based on unused remains Cheap Results are fast at hand -> no breeding (knock-out) required Easy to use Weak points This is not in vivo No complex plaque is there -> limited to the initial stages of disease Limited supply (for HTS) Hard to control precise shear Starts to leak after extended perfusion times (5 20 min) Potential host-graft reaction (vwf-dependent adhesion )

51 Strong points No animals required Completely human materials: no questionable transferability of mouse experiments to human disease / we are as close at human pathophysiology as possible No complicated approval of the local ethics committee: material is based on unused remains Cheap Results are fast at hand -> no breeding (knock-out) required Easy to use Weak points This is not in vivo No complex plaque is there -> limited to the initial stages of disease Limited supply (for HTS) Hard to control precise shear Starts to leak after extended perfusion times (5 20 min) Potential host-graft reaction (vwf-dependent adhesion )

52 Strong points No animals required Completely human materials: no questionable transferability of mouse experiments to human disease / we are as close at human pathophysiology as possible No complicated approval of the local ethics committee: material is based on unused remains Cheap Results are fast at hand -> no breeding (knock-out) required Easy to use Weak points This is not in vivo No complex plaque is there -> limited to the initial stages of disease Limited supply (for HTS) Hard to control precise shear Starts to leak after extended perfusion times (5 20 min) Potential host-graft reaction (vwf-dependent adhesion )

53 A novel µ-fluidic coagulation assay based on surface acoustic waves Biomicrofluidics 7, (2013); DMPA patent number international patent applications WO 2012/139752

54 SAW: surface acoustic waves to rapidly mix and recalcify blood

55 SAW: surface acoustic waves to rapidly mix and recalcify blood

56 Experimental setup

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59 dabigatran rivaroxaban

60 dabigatran rivaroxaban

61 Reduction number killed mice Conventional analysis (aptt, INR, TT) minimum need approximately ACL µl ACL top µl ACL top 700 > 300 µl SAW-CT: less than 6 µl required Vessel puncture is sufficient, no intracardial or liver puncture is required Knock-out mice does not need to be sacrificed

62 Reduction number killed mice Conventional analysis (aptt, INR, TT) minimum need approximately ACL µl ACL top µl ACL top 700 > 300 µl SAW-CT: less than 6 µl required Vessel puncture is sufficient, no intracardial or liver puncture is required Knock-out mice does not need to be sacrificed

63 Outlook Small study: Anticoagulated mice (dabigatran, rivaroxaban) + knock-out mice (platelet-deficient + GPVI -/- ) Compare results from conventional analyses to SAW-CT assay Can SAW-CT contribute 3R concept of Russell and Burch?