Mass Production of Human "Embryoid" Cells from Developmentally Frozen Embryos: Is It Ethical?

Abstract

Since their discovery in 2006 (Takahashi and Yamanaka 2006, 663), the so-called induced pluripotent stem (iPS) cells have been touted as the ethical alternative to using human embryonic stem cells (ESCs) for regenerative medicine. Cells capable of differentiating into all cell types in the adult organism were initially obtained from differentiated adult cells using a combination of transcription factors: Oct3/ 4, Sox2, Klf4, and c-Myc or the OSKM cocktail (Takahashi and Yamanaka 2006, 664) by using retroviruses to carry them into a skin cell. These factors then reprogram the skin cell to the ESC stage of development (Vogel and Holden 2007, 1224). These reprogrammed cells have been called iPS cells. There has been a rush to approve this reprogramming procedure by both Catholic ethicists and Church officials (Weiss 2007, A001; US Conference of Catholic Bishops [USCCB] 2007). The USCCB (2007) state “the goal sought for years through failed attempts at human cloning—the production of pluripotent stem cells that are an exact match to a patient—has been brought within reach by an ethical procedure”. One Catholic ethicist states “embryonic stem cells have no moral status” (Wade 2007). We have however expressed that caution is needed before openly accepting these new stem cell procedures (Burke, Pullicino, and Richard 2007, 204). Several new methods for obtaining cells capable of differentiating into all cell types in the adult organism have been developed. We would here like to comment on a recent report (Y. Zheng et al. 2019, 421) providing a method to mass produce multiple human embryo-like cells (MPEC) from human ESCs or iPS cells. The researchers use a microfluidic device that allows multiple embryos to grow simultaneously in a culture medium. There has been a recent call to debate the ethics of embryo models from stem cells (Rivron et al. 2018, 183; Y. L. Zheng, 2016, 1277), and here, we examine the ethics of the MPEC procedure. We also give some methodological background that may assist in determining what procedures could potentially be ethical. A careful examination of the MPEC procedure shows that the embryo-like structures produced in the procedure (from either ESCs or iPS cells) are ontologically indistinguishable from embryos. These embryos are prevented from reaching their full potential by depriving them of the extra-embryonic cells required for implantation into the uterus, and if they, along with the extra-embryonic cells, were implanted into a surrogate uterus, they could develop into a living human infant. It has been shown (Wernig et al. 2007, 318) that iPS cells can be made to form complete organisms when given access to the cells, which form the placenta and umbilical cord. In fact, in mice, both late