Self-Organization of Stem Cell Colonies and of Early Mammalian Embryos: Recent Experiments Shed New Light on the Role of Autonomy vs. External Instructions in Basic Body Plan Development

Ethical, legal, regulatory, and policy issues concerning embryoids: a systematic review of the literature

Recent advances in methods to culture pluripotent stem cells to model human development have resulted in entities that increasingly have recapitulated advanced stages of early embryo development. These entities, referred to by numerous terms such as embryoids, are becoming more sophisticated and could resemble human embryos ever more closely as research progresses. This paper reports a systematic review of the ethical, legal, regulatory, and policy questions and concerns found in the literature concerning human embryoid research published from 2016 to 2022. We identified 56 papers that use 53 distinct names or terms to refer to embryoids and four broad categories of ethical, legal, regulatory, or policy considerations in the literature: research justifications/benefits, ethical significance or moral status, permissible use, and regulatory and oversight challenges. Analyzing the full range of issues is a critical step toward fostering more robust ethical, legal, and social implications research in this emerging area and toward developing appropriate oversight.

Ethical Challenges in Organoid Use

Organoids hold great promises for numerous applications in biomedicine and biotechnology. Despite its potential in science, organoid technology poses complex ethical challenges that may hinder any future benefits for patients and society. This study aims to analyze the multifaceted ethical issues raised by organoids and recommend measures that must be taken at various levels to ensure the ethical use and application of this technology. Organoid technology raises several serious ethics issues related to the source of stem cells for organoid creation, informed consent and privacy of cell donors, the moral and legal status of organoids, the potential acquisition of human “characteristics or qualities”, use of gene editing, creation of chimeras, organoid transplantation, commercialization and patentability, issues of equity in the resulting treatments, potential misuse and dual use issues and long-term storage in biobanks. Existing guidelines and regulatory frameworks that are applicable to organoids are also discussed. It is concluded that despite the serious ethical challenges posed by organoid use and biobanking, we have a moral obligation to support organoid research and ensure that we do not lose any of the potential benefits that organoids offer. In this direction, a four-step approach is recommended, which includes existing regulations and guidelines, special regulatory provisions that may be needed, public engagement and continuous monitoring of the rapid advancements in the field. This approach may help maximize the biomedical and social benefits of organoid technology and contribute to future governance models in organoid technology.

Autonomy in the Development of Stem Cell-Derived Embryoids: Sprouting Blastocyst-Like Cysts, and Ethical Implications

The experimental production of complex structures resembling mammalian embryos (e.g., blastoids, gastruloids) from pluripotent stem cells in vitro has become a booming research field. Since some of these embryoid models appear to reach a degree of complexity that may come close to viability, a broad discussion has set in with the aim to arrive at a consensus on the ethical implications with regard to acceptability of the use of this technology with human cells. The present text focuses on aspects of the gain of organismic wholeness of such stem cell-derived constructs, and of autonomy of self-organization, raised by recent reports on blastocyst-like cysts spontaneously budding in mouse stem cell cultures, and by previous reports on likewise spontaneous formation of gastrulating embryonic disc-like structures in primate models. Mechanisms of pattern (axis) formation in early embryogenesis are discussed in the context of self-organization of stem cell clusters. It is concluded that ethical aspects of development of organismic wholeness in the formation of embryoids need to receive more attention in the present discussions about new legal regulations in this field.

Expanded potential: the key to synthetic embryo?

How does an embryo acquire totipotency and develop into an adult is a fundamental scientific question. Stem cells derived from pre-implantation embryos or reprogrammed from somatic cells with totipotency features have been established. They have enriched molecular features, including transcription, epigenetic modification, chromatin structure and metabolism, similar to early embryos from 2 cell (2C) to morula. Functionally, they display a broader developmental potential to differentiate into cell types in the embryonic and extraembryonic tissues. The expanded developmental potential was further demonstrated by inducing these stem cells into embryo-like structures alone or aggregating with other embryo-derived stem cells. The synthetic embryo-like structures not only facilitate the dissection of key events in early embryonic development, but also serve as a model for investigating pregnancy related complications.

From single cells to tissue self-organization

Self-organization is a process by which interacting cells organize and arrange themselves in higher order structures and patterns. To achieve this, cells must have molecular mechanisms to sense their complex local environment and interpret it to respond accordingly. A combination of cell-intrinsic and cell-extrinsic cues are decoded by the single cells dictating their behaviour, their differentiation and symmetry-breaking potential driving development, tissue remodeling and regenerative processes. A unifying property of these self-organized pattern-forming systems is the importance of fluctuations, cell-to-cell variability, or noise. Cell-to-cell variability is an inherent and emergent property of populations of cells that maximize the population performance instead of the individual cell, providing tissues the flexibility to develop and maintain homeostasis in diverse environments. In this review, we will explore the role of self-organization and cell-to-cell variability as fundamental properties of multicellularity-and the requisite of single-cell resolution for its understanding. Moreover, we will analyze how single cells generate emergent multicellular dynamics observed at the tissue level 'travelling' across different scales: spatial, temporal and functional.

Deconstructing and reconstructing the mouse and human early embryo

The emergence of form and function during mammalian embryogenesis is a complex process that involves multiple regulatory levels. The foundations of the body plan are laid throughout the first days of post-implantation development as embryonic stem cells undergo symmetry breaking and initiate lineage specification, in a process that coincides with a global morphological reorganization of the embryo. Here, we review experimental models and how they have shaped our current understanding of the post-implantation mammalian embryo.

Ethical issues in genetic modification and why application matters

Advances in genome editing techniques have generated renewed interest in the ethical implications of genetic modification. In this article, we review the recent literature and discuss in detail ethical issues pertaining to the application of this technology to five areas; human embryo research, organoid research, the prospect of genetically modified babies, mitochondrial replacement therapy and the creation of chimeric organisms. We point to a central issue which cuts through these different areas: the need to clearly frame how using the technology provides benefit that cannot be met by other means. Failure to provide reasonable justification, and address how risks-if any-will be mitigated, is likely to erode public trust and undermine progress in medical research and its clinical translation.