Organ pre-treatment with cytotopic endothelial localising peptides to ameliorate microvascular thrombosis & perfusion deficits in ex-vivo renal haemo-reperfusion models
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Background: Hypothermic machine organ perfusion (HMP) offers opportunity to manipulate grafts with pharmacological agents prior to transplantation. Pre-treating organs with novel cytotopic anti-coagulant peptides that localise to endothelial cell membranes could ameliorate microvascular thrombotic sequelae post-transplantation. We describe experiments testing Thrombalexin (TLN), a novel cell binding thrombin-inhibitor, using porcine and unused human kidneys in a series of ex-vivo normothermic haemo-reperfusion models.
Methods: 38 porcine kidneys were utilised. Control kidneys underwent pretreatment via HMP with either unmodified perfusion solution (n=15) or solution with Inactive-TLN (absent anticoagulant effect, n=4). Test kidneys were perfused with TLN treated solution (n=19). All kidneys then underwent haemo-reperfusion. Two unused human kidneys underwent a similar protocol.
Results: HMP pretreatment facilitated delivery and tethering of TLN in the organ microvasculature. Haemo-reperfusion challenge demonstrated improved perfusion in TLN-treated kidneys compared to controls: 26.4% superior flow (30.6 vs.23.1 ml/min/100g,p=0.019) and 28.9% higher perfusion flow indices (0.43 vs.0.32 ml/min/100g/mmHg,p=0.049). Orthogonal polarisation spectral imaging demonstrated superior microvascular capillary perfusion in TLN-treated organs vs. controls (9.1 vs. 2.8pl/s/mm2,p=0.021). Rapid-sampling microdialysis for cortical [lactate] as a marker of tissue ischaemia/metabolism detected lower levels in TLN-treated kidneys. Perfusate analysis demonstrated reduced fibrin generation in TLN-treated kidneys correlating with perfusion data.
Conclusion: Our data suggest HMP graft pretreatment with cytotopic anticoagulants is feasible and ameliorates perfusion deficits seen in ex-vivo haemo-reperfusion models. There is potential for further development and application of this translational strategy to deliver locally-active anti-coagulants directly within grafts and decrease microvascular thrombotic sequelae, while avoiding systemic anticoagulation and its associated risks.
Methods: 38 porcine kidneys were utilised. Control kidneys underwent pretreatment via HMP with either unmodified perfusion solution (n=15) or solution with Inactive-TLN (absent anticoagulant effect, n=4). Test kidneys were perfused with TLN treated solution (n=19). All kidneys then underwent haemo-reperfusion. Two unused human kidneys underwent a similar protocol.
Results: HMP pretreatment facilitated delivery and tethering of TLN in the organ microvasculature. Haemo-reperfusion challenge demonstrated improved perfusion in TLN-treated kidneys compared to controls: 26.4% superior flow (30.6 vs.23.1 ml/min/100g,p=0.019) and 28.9% higher perfusion flow indices (0.43 vs.0.32 ml/min/100g/mmHg,p=0.049). Orthogonal polarisation spectral imaging demonstrated superior microvascular capillary perfusion in TLN-treated organs vs. controls (9.1 vs. 2.8pl/s/mm2,p=0.021). Rapid-sampling microdialysis for cortical [lactate] as a marker of tissue ischaemia/metabolism detected lower levels in TLN-treated kidneys. Perfusate analysis demonstrated reduced fibrin generation in TLN-treated kidneys correlating with perfusion data.
Conclusion: Our data suggest HMP graft pretreatment with cytotopic anticoagulants is feasible and ameliorates perfusion deficits seen in ex-vivo haemo-reperfusion models. There is potential for further development and application of this translational strategy to deliver locally-active anti-coagulants directly within grafts and decrease microvascular thrombotic sequelae, while avoiding systemic anticoagulation and its associated risks.
Date Issued
2016-12-01
Date Acceptance
2016-07-17
Citation
Transplantation, 2016, 100 (12), pp.e128-e139
ISSN
1534-6080
Publisher
Lippincott, Williams & Wilkins
Start Page
e128
End Page
e139
Journal / Book Title
Transplantation
Volume
100
Issue
12
Replaces
10044/1/39433
Copyright Statement
© 2016 Wolters Kluwer Health, Inc. All rights reserved.
Subjects
Science & Technology
Life Sciences & Biomedicine
Immunology
Surgery
Transplantation
DELAYED GRAFT FUNCTION
NO-REFLOW PHENOMENON
REPERFUSION INJURY
KIDNEY-TRANSPLANTATION
ISCHEMIA/REPERFUSION INJURY
COMPLEMENT INHIBITOR
APT070 MIROCOCEPT
IN-VIVO
EXPRESSION
INFLAMMATION
11 Medical And Health Sciences
Publication Status
Published