Chimeric pigs harboring organs derived from human stem cells are promising for patient-specific regenerative therapies. Induced pluripotent stem cells (iPSCs) can contribute to all cell types of the fetus, including germline after injection into embryos. However, ethical concerns prohibit testing human iPSCs in chimera assays. Here, we evaluated porcine embryos as hosts for an interspecies chimera assay using iPSCs from either cynomolgus monkeys (cyiPSCs) or mouse (miPSCs). To establish an in vitro culture system compatible for cyiPSCs and porcine embryos, we determined blastocyst development in eight different stem cell media. The highest developmental rates of blastocysts were achieved in Knockout Dulbecco's modified Eagle's medium with 20% knockout serum replacement. We found that cyiPSCs injected into porcine embryos survived in vitro and were mostly located in the trophectoderm (TE). Instead, when miPSCs were injected into porcine embryos, the cells rapidly proliferated. The behavior of chimeras developed in vitro was recapitulated in vivo; cyiPSCs were observed in the TE, but not in the porcine epiblast. However, when miPSCs were injected into in vivo derived porcine embryos, mouse cells were found in both, the epiblast and TE. These results demonstrate that porcine embryos could be useful for evaluating the interspecies chimera-forming ability of iPSCs from different species.

中文翻译：

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使用早期猪胚的体外和体内种间嵌合体测定。

带有人类干细胞器官的嵌合猪有望用于患者特异性的再生治疗。诱导型多能干细胞（iPSC）可以对胎儿的所有细胞类型都有贡献，包括注入胚胎后的种系。但是，出于道德考虑，禁止在嵌合体分析中测试人iPSC。在这里，我们使用来自食蟹猴（cyiPSC）或小鼠（miPSC）的iPSC对猪胚胎作为宿主进行种间嵌合体测定。建立体外培养系统兼容cyiPSCs和猪胚胎，我们确定了8种不同干细胞培养基中胚泡的发育。在敲除Dulbecco改良的Eagle's培养基中使用20％的敲除血清替代品可达到最高的胚泡发育率。我们发现注射到猪胚胎中的cyiPSCs在体外存活，并且大部分位于滋养外胚层（TE）中。相反，当将miPSC注射到猪胚胎中时，细胞迅速增殖。嵌合体的开发的行为在体外被概括在体内; 在TE中观察到cyiPSC，但在猪上皮细胞中未观察到。但是，当将miPSC注射入体内时来源于猪的胚胎，在上皮细胞和TE中都发现了小鼠细胞。这些结果表明，猪胚胎可用于评估不同物种的iPSC的种间嵌合体形成能力。