Iwase Hayato, Hara Hidetaka, Ezzelarab Mohamed, Li Tao, Zhang Zhongqiang, Gao Bingsi, Liu Hong, Long Cassandra, Wang Yi, Cassano Amy, Klein Edwin, Phelps Carol, Ayares David, Humar Abhinav, Wijkstrom Martin, Cooper David K C
Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
Center for Kidney Transplantation, Second Affiliated Hospital of the University of South China, Hengyang, Hunan, China.
Xenotransplantation. 2017 Mar;24(2). doi: 10.1111/xen.12293. Epub 2017 Mar 17.
Genetically engineered pigs could provide a source of kidneys for clinical transplantation. The two longest kidney graft survivals reported to date have been 136 and 310 days, but graft survival >30 days has been unusual until recently.
Donor pigs (n=4) were on an α1,3-galactosyltransferase gene-knockout (GTKO)/human complement regulatory protein (CD46) background (GTKO/CD46). In addition, the pigs were transgenic for at least one human coagulation regulatory protein. Two baboons received a kidney from a six-gene pig (GroupA) and two from a three-gene pig (GroupB). Immunosuppressive therapy was identical in all four cases and consisted of anti-thymoglobulin (ATG)+anti-CD20mAb (induction) and anti-CD40mAb+rapamycin+corticosteroids (maintenance). Anti-TNF-α and anti-IL-6R mAbs were administered to reduce the inflammatory response. Baboons were followed by clinical/laboratory monitoring of immune/coagulation/inflammatory/physiological parameters. At biopsy or euthanasia, the grafts were examined by microscopy.
The two GroupA baboons remained healthy with normal renal function >7 and >8 months, respectively, but then developed infectious complications. However, no features of a consumptive coagulopathy, eg, thrombocytopenia and reduction of fibrinogen, or of a protein-losing nephropathy were observed. There was no evidence of an elicited anti-pig antibody response, and histology of biopsies taken at approximately 4, 6, and 7 months and at necropsy showed no significant abnormalities. In contrast, both GroupB baboons developed features of a consumptive coagulopathy and required euthanasia on day 12.
The combination of (i) a graft from a specific six-gene genetically modified pig, (ii) an effective immunosuppressive regimen, and (iii) anti-inflammatory therapy prevented immune injury, a protein-losing nephropathy, and coagulation dysfunction for >7 months. Although the number of experiments is very limited, our impression is that expression of human endothelial protein C receptor (±CD55) in the graft is important if coagulation dysregulation is to be avoided.
基因工程猪可为临床移植提供肾脏来源。迄今为止报道的最长肾脏移植存活时间分别为136天和310天，但直到最近，移植存活时间超过30天的情况并不常见。
供体猪（n = 4）具有α1,3 - 半乳糖基转移酶基因敲除（GTKO）/人补体调节蛋白（CD46）背景（GTKO/CD46）。此外，这些猪还转染了至少一种人凝血调节蛋白基因。两只狒狒接受了来自六基因猪的肾脏（A组），另外两只接受了来自三基因猪的肾脏（B组）。所有四例的免疫抑制治疗相同，包括抗胸腺细胞球蛋白（ATG）+抗CD20单克隆抗体（诱导期）以及抗CD40单克隆抗体+雷帕霉素+皮质类固醇（维持期）。给予抗TNF-α和抗IL-6R单克隆抗体以减轻炎症反应。通过临床/实验室监测狒狒的免疫/凝血/炎症/生理参数。在活检或安乐死时，通过显微镜检查移植物。
两只A组狒狒分别在超过7个月和8个月时保持健康且肾功能正常，但随后出现感染并发症。然而，未观察到消耗性凝血病的特征，如血小板减少和纤维蛋白原降低，也未观察到蛋白丢失性肾病的特征。没有证据表明引发了抗猪抗体反应，并且在大约4、6和7个月时以及尸检时所取活检组织的组织学检查未显示明显异常。相比之下，两只B组狒狒均出现了消耗性凝血病的特征，并在第12天需要实施安乐死。
（i）来自特定六基因转基因猪的移植物、（ii）有效的免疫抑制方案以及（iii）抗炎治疗的联合应用可预防免疫损伤、蛋白丢失性肾病和凝血功能障碍超过7个月。尽管实验数量非常有限，但我们的印象是，如果要避免凝血调节异常，移植物中人内皮蛋白C受体（±CD55）的表达很重要。
