The fate of human platelets perfused through the pig liver: implications for xenotransplantation
The fate of human platelets perfused through the pig liver: implications for xenotransplantation
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DOI：
10.1111/j.1399-3089.2010.00605.x
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发表时间：
2010-09-01
影响因子：
3.9
通讯作者：
Tector, A. Joseph
中科院分区：
文献类型：
--
作者：
Burlak, Christopher;Paris, Leela L.;Tector, A. Joseph
背景：异种猪肝移植可以弥补原位肝移植可用肝脏的不足。在猪和狒狒肝脏异种移植的研究显示，主要障碍是致命的血小板减少症，发生在几分钟到几个小时的transplantation.Methods：我们已经建立了一个模型，异种移植诱导的血小板减少症使用离体猪肝灌注与人类血小板。血小板减少症进行了检查，使用荧光标记的血小板在离体灌注和共培养与原代肝窦内皮细胞（LSEC）。结果：离体肝灌注显示，93%的人血小板从循环中取出后15分钟。内皮细胞和血小板未激活的基础上组织因子释放到灌注液。在15和30分钟时离体灌注的活组织检查和体外分析表明，人血小板被猪LSEC吞噬并在吞噬体中降解。将血小板加入离体灌注系统后60至120分钟，我们观察到肝细胞中的血小板碎片和降解的血小板。血小板吞噬作用不受调理作用介导，因为Fc阻断对血小板吞噬作用没有影响。原代LSEC培养物对人血小板的体外摄取在15分钟时达到峰值，3小时后血小板荧光降低55%以上。含有人血小板的主要猪LSEC吞噬体与溶酶体相关膜蛋白-1（LAMP 1）呈阳性的溶酶体共定位，表明猪LSEC内成熟吞噬体的形成。结论：我们观察到猪LSEC吞噬人血小板描述了一种新的机制，在肝脏中的大颗粒摄取。研究异种移植诱导的血小板减少症的模型系统的建立使得研究介导血小板损失的机制成为可能。
Background:Pig liver xenotransplantation could offset the shortage of livers available for orthotopic liver transplantation. Studies in pig and baboon liver xenografts revealed the main obstacle to be a lethal thrombocytopenia that occurred within minutes to hours of transplantation.Methods:We have created a model of xenotransplantation-induced thrombocytopenia using ex vivo pig liver perfusion with human platelets. Thrombocytopenia was examined using fluorescently labeled platelets during the ex vivo perfusion and coculture with primary liver sinusoidal endothelial cells (LSEC).Results:Ex vivo liver perfusion revealed that 93% of human platelets were removed from circulation after 15 min. Endothelial cells and platelets were not activated based on tissue factor release into the perfusate. Biopsies from the ex vivo perfusion at 15 and 30 min and in vitro analysis indicated that human platelets are phagocytosed by pig LSEC and degraded in phagosomes. Sixty to 120 min after the addition of platelets to the ex vivo perfusion system, we observed platelet fragments and degraded platelets in hepatocytes. Platelet phagocytosis was not mediated by opsonization as Fc blocking had no effect on platelet phagocytosis. In vitro uptake of human platelets by primary LSEC cultures peaked at 15 min followed by a greater than 55% decrease in platelet fluorescence after 3 h. Primary pig LSEC phagosomes containing human platelets were colocalized with lysosomes positive for lysosome-associated membrane protein-1 (LAMP1), indicating the formation of mature phagosomes within pig LSEC.Conclusions:Our observation of pig LSEC phagocytosis of human platelets describes a novel mechanism of large-particle uptake in the liver. The creation of a model system to study xenotransplantation-induced thrombocytopenia makes possible the investigation into mechanisms that mediate platelet loss.