Ramackers Wolf, Friedrich Lars, Klose Johannes, Vondran Florian, Bergmann Sabine, Schüttler Wolfgang, Johanning Kai, Werwitzke Sonja, Trummer Arne, Bröcker Verena, Klempnauer Jürgen, Winkler Michael, Tiede Andreas
Department of General, Visceral and Transplantation Surgery, Hannover Medical School, Hannover, Germany.
Xenotransplantation. 2014 Jul-Aug;21(4):367-75. doi: 10.1111/xen.12104. Epub 2014 May 8.
Xenogenic activation of hemostasis (XAH) represents a major hurdle for the transplantation of discordant animal organs into humans as it results in thrombotic microangiopathy (TMA). We have previously shown that recombinant human-activated protein C (rhAPC) mitigates XAH and TMA in an ex vivo model of pig-to-human kidney transplantation. However, the use of rhAPC may not be feasible in a perioperative setting due to possible bleeding complications.
Here, we explored the effects of another natural inhibitor of coagulation, human recombinant antithrombin (rhAT), in comparison with rhAPC. Unmodified porcine kidneys (n = 25) were perfused ex vivo with porcine blood, human blood, or human blood supplemented with rhAPC or rhAT. Surrogate parameters of organ survival, markers of XAH (D- Dimer, thrombin-antithrombin complex [TAT], fibrinogen, antithrombin activity, plasminogen), endothelial cell and platelet activation (E-selectin, P-selectin), platelet function tests and histological signs of TMA were evaluated.
Perfusion was feasible for > 240 min in all experiments with autologous porcine blood, but limited to 126 ± 78 min with human blood due to increased vascular resistance. Addition of rhAT protected from TMA and allowed for perfusion times > 240 min. In addition, there were less signs of XAH with reduced release of P-selectin and overexpression of E-selectin, whereas the progressive loss of platelet function, observed during discordant perfusion, was prevented. The effect of rhAT was dose-dependent with maximum protection obtained at 3 IU/ml.
In conclusion, in this ex vivo model of discordant xenotransplantation, rhAT reduced XAH and prevented TMA in doses that appear feasible for use in clinical or preclinical transplantation settings.
异种止血激活（XAH）是将不匹配的动物器官移植到人类体内的一个主要障碍，因为它会导致血栓性微血管病（TMA）。我们之前已经表明，重组人活化蛋白C（rhAPC）在猪到人的肾脏移植体外模型中可减轻XAH和TMA。然而，由于可能出现出血并发症，在围手术期使用rhAPC可能不可行。
在此，我们探索了另一种天然凝血抑制剂人重组抗凝血酶（rhAT）与rhAPC相比的效果。将未修饰的猪肾（n = 25）用猪血、人血或补充有rhAPC或rhAT的人血进行体外灌注。评估了器官存活的替代参数、XAH标志物（D - 二聚体、凝血酶 - 抗凝血酶复合物[TAT]、纤维蛋白原、抗凝血酶活性、纤溶酶原）、内皮细胞和血小板活化（E - 选择素、P - 选择素）、血小板功能测试以及TMA的组织学迹象。
在所有使用自体猪血的实验中，灌注可持续超过240分钟，但使用人血时，由于血管阻力增加，灌注时间限制在126±78分钟。添加rhAT可预防TMA，并使灌注时间超过240分钟。此外，XAH迹象减少，P - 选择素释放减少，E - 选择素过表达减少，同时防止了在不匹配灌注期间观察到的血小板功能逐渐丧失。rhAT的作用呈剂量依赖性，在3 IU/ml时获得最大保护。
总之，在这个不匹配异种移植的体外模型中，rhAT以在临床或临床前移植环境中似乎可行的剂量减少了XAH并预防了TMA。
