Effects of coagulation proteases inhibition in a renal ischemia reperfusion porcine model

La pénurie d’organes est un problème majeur en transplantation, aussi, en France, depuis 2005 sont autorisés les prélèvements sur donneurs décédés après arrêt cardiaque (DDAC). Cependant, ces organes sont soumis à d’importantes lésions d’ischémie reperfusion, en particulier liés à la coagulation induite par la stase. La formation de microthrombi entraîne à la reperfusion un défaut d’irrigation qui aboutit à la mort celullaire. Parallèlement, l’endothélium rénal amplifie la coagulation par l’expression du facteur tissulaire. Ce processus engendre une synthèse accrue de molécules pro-inflammatoires via les PAR (Protease-Activated-Receptors) activés par les facteurs IIa et Xa. Dans le cadre de ce travail, nous avons évalué in vivo, dans un modèle porcin d’autotransplantation rénale, l’effet de deux molécules anticoagulantes de synthèse, l’une anti-Xa et l’autre combinant un effet anti-Xa et IIa. Le modèle préclinique était composé d’une période d’ischémie chaude suivie d’une conservation de 24h à 4°C en UW, modèle sévère mimant les lésions observées chez le DDAC. L’utilisation de ces anticoagulants en périconservation, a permis de réduire les lésions de fibrose et le l’inflammation responsables de la perte de greffon rénal à long terme. In vitro, les effets bénéfiques de la molécule anti-Xa+IIa, seraient dus à une limitation de l’activation endothéliale et une réduction de l’inflammation. En conclusion, l’ajout de ces anticoagulants durant la conservation des greffons a montré un bénéfice sur la reprise de fonction et sur la réduction des dysfonctions chroniques des greffons.Organ shortage is a major limitation for transplantation, then since 2005 the use of deceased after cardiac arrest donors (DDAC) became legal in France. However these organs undergo severe ischemia-reperfusion injury, partly due to stasis activated coagulation. Micro-thrombi impair a correct reperfusion of the implanted organ. Conversely activated renal endothelium is the cause of an amplification of coagulation. This leads to increased production of proinflammatory molecules via the PAR (protease-activated receptors) activation by coagulation factors IIa and Xa. In this work we have used a severe in vivo ischemia-reperfusion model and tested the effect of inhibitors of Xa and IIa on the outcome of renal autotransplantation. One of these synthetic molecules was an anti-Xa heparinoid, while the other was acombined of direct anti-IIa + anti-Xa heparinoid. The pre-clinical model included a sequence of warm ischemia followed by a cold storage 24 h at 4°C in UW, mimicking what happens in DDAC. The use of both molecules during peri-preservation was followed by a reduction of fibrosis and inflammation, known to cause long term kidney loss. In an in vitro model, we have shown that beneficial effects of the combined anti IIa-Xa could be the consequence of a reduction in endothelial activation and subsequent inflammation. We conclude that anti Xa, and anti Xa-IIa, use during organ conservation, is beneficial for kidney function and survival and that they may be used as protectors against chronic renal dysfunction

High throughput proteomic exploration of cold ischemia mechanisms

High throughput proteomic exploration of cold ischemia mechanisms. 17. Congress of the European Society for Organ Transplantatio

Influence of Hypoxic Preservation Temperature on Endothelial Cells and Kidney Integrity

International audienceIschemia-reperfusion (IR) injury is unavoidable during organ transplantation and impacts graft quality. New paradigms areemerging including preservation at higher temperature than “hypothermia” or “cold”: although 4∘Cremainslargelyusedforkidney preservation, recent studies challenged this choice. We and others hypothesized that a higher preservation temperature,closer to physiological regimen, could improve organ quality. For this purpose, we used anin vitromodel of endothelial cellsexposed to hypoxia-reoxygenation sequence (mimicking IR) and anex vivoischemic pig kidneys static storage model.In vitro,19∘C, 27∘C, and 32∘C provided protection against injuries versus 4∘C, by reducing cell death, mitochondrial dysfunction, leukocyteadhesion, and inflammation. However,ex vivo, the benefits of 19∘Cor32∘C were limited, showing similar levels of tissue preservationdamage.Ex vivo4∘C-preserved kidneys displayed a trend towards reduced damage, including apoptosis. Macrophage infiltration,tubulitis, and necrosis were increased in the 19∘Cand32∘Cversus4∘C preserved kidneys. Thus, despite a trend for an advantageof subnormothermia as preservation temperature, ourin vitroandex vivomodels bring different insights in terms of preservationtemperature effect. This study suggests that temperature optimization for kidney preservation will require thorough investigation,combining the use of complementary relevant models and the design of elaborated preservation solution and new technologies

Dynamic transcriptomic analysis of ischemic injury in a porcine pre-clinical model mimicking donors deceased after circulatory death

Due to organ shortage, clinicians are prone to consider alternative type of organ donors among them donors deceased after circulatory death (DCD). However, especially using these organs which are more prone to graft dysfunction, there is a need to better understand mechanistic events ocuring during ischemia phase and leading to ischemia/reperfusion injuries (IRI). The aim of this study is to provide a dynamic transcriptomic analysis of preclinical porcine model kidneys subjected to ischemic stress mimicking DCD donor. We compared cortex and corticomedullary junction (CMJ) tissues from porcine kidneys submitted to 60 min warm ischemia (WI) followed by 0, 6 or 24 hours of cold storage in University of Wisconsin solution versus control non-ischemic kidneys (n=5 per group). 29 cortex genes and 113 CMJ genes were significantly up or down-regulated after WI versus healthy kidneys, and up to 400 genes were regulated after WI followed by 6 or 24 hours of cold storage (p < 0.05). Functionnal enrichment analysis (home selected gene kinetic classification, Gene-ontology-biological processes and Gene-ontology-molecular-function) revealed relevant genes implication during WI and cold storage. We uncovered targets which we will further validate as biomarkers and new therapeutic targets to optimize graft kidney quality before transplantation and improve whole transplantation outcome

Dynamic transcriptomic analysis of ischemic injury in a porcine pre-clinical model mimicking donors deceased after circulatory death

Présenté au: 18. Annual Congress of the French Speaking Transplantation SocietyToulouse FranceDate: 4 au 7 décembre 2018International audienceIntroduction: Due to organ shortage, clinicians are prone to consider alternative type of organ donors among them donors deceased after circulatory death (DCD). However, especially using these organs which are more prone to graft dysfunction, there is a need to better understand mechanistic events occurring during ischemia phase and leading to ischemia/reperfusion injuries (IRI). The aim of this study is to provide a dynamic transcriptomic analysis of preclinical porcine model kidneys subjected to ischemic stress mimicking DCD donor.Methods: We compared cortex and corticomedullary junction (CMJ) tissues from porcine kidneys submitting to 60 min warm ischemia (WI) followed by 0, 6 or 24 h of cold storage in University of Wisconsin solution versus control non‐ischemic kidneys (n = 5 per group).Results: 29 cortex genes and 113 CMJ genes were significantly up or down‐regulated after WI versus healthy kidneys, and up to 400 genes were regulated after WI and more 6 or 24 h of cold storage (p < 0.05). Home selected gene kinetic classification, Gene‐ontology‐biological processes and Gene‐ontology‐molecular‐function functional enrichment analysis revealed relevant genes implication during WI and cold storage.Conclusion: We uncovered targets which we will further validate as biomarkers and new therapeutic targets to optimize graft kidney quality before transplantation and improve whole transplantation outcome

Dynamic transcriptomic analysis of ischemic injury in a porcine pre-clinical model mimicking donors deceased after circulatory death

Présenté au: 18. Annual Congress of the French Speaking Transplantation SocietyToulouse FranceDate: 4 au 7 décembre 2018Introduction: Due to organ shortage, clinicians are prone to consider alternative type of organ donors among them donors deceased after circulatory death (DCD). However, especially using these organs which are more prone to graft dysfunction, there is a need to better understand mechanistic events occurring during ischemia phase and leading to ischemia/reperfusion injuries (IRI). The aim of this study is to provide a dynamic transcriptomic analysis of preclinical porcine model kidneys subjected to ischemic stress mimicking DCD donor.Methods: We compared cortex and corticomedullary junction (CMJ) tissues from porcine kidneys submitting to 60 min warm ischemia (WI) followed by 0, 6 or 24 h of cold storage in University of Wisconsin solution versus control non‐ischemic kidneys (n = 5 per group).Results: 29 cortex genes and 113 CMJ genes were significantly up or down‐regulated after WI versus healthy kidneys, and up to 400 genes were regulated after WI and more 6 or 24 h of cold storage (p < 0.05). Home selected gene kinetic classification, Gene‐ontology‐biological processes and Gene‐ontology‐molecular‐function functional enrichment analysis revealed relevant genes implication during WI and cold storage.Conclusion: We uncovered targets which we will further validate as biomarkers and new therapeutic targets to optimize graft kidney quality before transplantation and improve whole transplantation outcome

Inhibition of coagulation proteases Xa and IIa decreases ischemia-reperfusion injuries in a preclinical renal transplantation model.

International audienceCoagulation is an important pathway in the pathophysiology of ischemia-reperfusion injuries. In particular, deceased after circulatory death (DCD) donors undergo a no-flow period, a strong activator of coagulation. Hence, therapies influencing the coagulation cascade must be developed. We evaluated the effect of a new highly specific and effective anti-Xa/IIa molecule, with an integrated innovative antidote site (EP217609), in a porcine preclinical model mimicking injuries observed in DCD donor kidney transplantation. Kidneys were clamped for 60 minutes (warm ischemia), then flushed and preserved for 24 hours at 4°C in University of Wisconsin (UW) solution (supplemented or not). EP217609-supplemented UW solution (UW-EP), compared with unfractionated heparin-supplemented UW solution (UW-UFH) or UW alone (UW). A mechanistic investigation was conducted in vitro: addition of EP217609 to endothelial cells during hypoxia at 4°C in the UW solution inhibited thrombin generation during reoxygenation at 37°C in human plasma and reduced tumor necrosis factor alpha, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 messenger RNA cell expressions. In vivo, function recovery was markedly improved in the UW-EP group. Interestingly, levels of thrombin-antithrombin complexes (reflecting thrombin generation) were reduced 60 minutes after reperfusion in the UW-EP group. In addition, 3 months after transplantation, lower fibrosis, epithelial-mesenchymal transition, inflammation, and leukocyte infiltration were observed. Using this new dual anticoagulant, anti-Xa/IIa activity during kidney flush and preservation is protected by reducing thrombin generation at revascularization, improving early function recovery, and decreasing chronic lesions. Such an easy-to-deploy clinical strategy could improve marginal graft outcome