An ethical framework for human embryology with embryo models.

A human embryo's legal definition and its entitlement to protection vary greatly worldwide. Recently, human pluripotent stem cells have been used to form in vitro models of early embryos that have challenged legal definitions and raised questions regarding their usage. In this light, we propose a refined legal definition of an embryo, suggest "tipping points" for when human embryo models could eventually be afforded similar protection to that of embryos, and then revisit basic ethical principles that might help to draft a roadmap for the gradual, justified usage of embryo models in a manner that aims to maximize benefits to society.

Perspectiva legal del manejo de embriones supernumerarios en Italia. Soluciones prácticas de Derecho comparado / [Legal perspective of the management of supernumerary embryos in Italy. Practical Comparative Law Solutions]

Los avances en el ámbito de la medicina reproductiva han situado en un lugar destacado una nueva entidad: el embrión humano. La reconstrucción de su identidad jurídica reviste una importancia primordial en aras de encontrar soluciones a una de las cuestiones más sensibles que actualmente impulsan el debate en el contexto italiano, a saber, el destino de los embriones supernumerarios. La presente contribución realiza una sucinta revisión de las aportaciones efectuadas por la doctrina y la jurisprudencia tanto a nivel nacional como europeo en relación con este asunto, para posteriormente ahondar en algunas propuestas de carácter práctico, analizando sus potencialidades y aspectos críticos. (AU)

The advances in the field of reproductive medicine have placed a new entity at the forefront: the human embryo. The reconstruction of its legal identity assumes paramount importance in the pursuit of finding solutions to one of the most sensitive issues currently driving the debate in the Italian context, namely, the fate of supernumerary embryos. This contribution provides a concise review of the contributions made by doctrine and jurisprudence, both at the national and European levels, concerning this matter. Subsequently, it delves into some practical proposals, analyzing their potentialities and critical aspects. (AU)

Shadowed by past, gene-editing summit looks to future.

London meeting touts sickle cell success, but questions about embryo editing linger.

From the maternal uterus to the "uterus device"? Ethical and scientific considerations on partial ectogenesis.

The article aims to elaborate the progress made in partial ectogenesis research on sheep as well as human embryos. Since the ban on embryos experimentation after the 14-day window is a major roadblock in terms of partial ectogenesis research, the authors have weighed the possibility that such a ban could be reconsidered. In favor of easing such a restriction, it may be argued that: (a) unlike the Catholic approach, prevalent ethics precepts hold that the embryo's interest ought to be balanced against the interests of the other parties involved; (b) an extension of the 14-day deadline would no longer make ethically untenable practices acceptable; hence, the "slippery slope" argument, although generally worthy, would not conclusively apply to partial ectogenesis; (c) in mainstream embryo research efforts, there is a conflict between the lives of embryos and the health of individuals already born; as for partial ectogenesis, however, such a conflict would be between the lives of embryos and the lives of fetuses which would not survive otherwise. Still, in light of the embryo's status as a human being, the authors conclude that such research practices should only be allowed on supernumerary embryos.

Research on supernumerary embryos: the challenge of recon- ciling opposing interests and fast-evolving technologies.

ABSTRACT: The paper addresses the issue of the legality and ethical admissi-bility of invasive experiments on embryos and the correlated one of the degree of legal protection and dignity to be recognized for human embryos, particularly in light of the growing importance that scientific research on embryonic stem cells has been gaining from the clinical and biomedical standpoints in the therapeutic treatments of diseases so far considered incurable, in the interest of public health. Furthermore, the issue of experimentation on cryopreserved supernumerary human embryos is still extremely polarizing, which makes it harder to arrive at shared solutions. The author hopes for a broad-ranging debate at the international level, for the ultimate purpose of achieving shared regulatory frameworks.

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.

Disposition of unclaimed embryos: an Ethics Committee opinion.

Programs should create and enforce written policies addressing the designation, retention, and disposal of unclaimed embryos. In the absence of program-specific policies, it is ethically permissible for a program or facility to consider embryos to have been unclaimed if a reasonable period of time has passed since contact with an individual or couple; efforts as outlined in the consent form have been made to contact the individual or couple; and no written instructions from the individual or couple with dispositional control exist concerning disposition. In such cases, programs or facilities may dispose of unclaimed embryos by removing them from storage and thawing without transfer. In the absence of specific written instructions, unclaimed embryos may not be donated to others for reproductive use or be used in research. This statement replaces the American Society for Reproductive Medicine Ethics Committee document "Disposition of Abandoned Embryos" published in 2013.

Human embryo research, stem cell-derived embryo models and in vitro gametogenesis: Considerations leading to the revised ISSCR guidelines.

The ISSCR Guidelines for Stem Cell Research and Clinical Translation were last revised in 2016. Since then, rapid progress has been made in research areas related to in vitro culture of human embryos, creation of stem cell-based embryo models, and in vitro gametogenesis. Therefore, a working group of international experts was convened to review the oversight process and provide an update to the guidelines. This report captures the discussion and summarizes the major recommendations made by this working group, with a specific emphasis on updating the categories of review and engagement with the specialized scientific and ethical oversight process.

ISSCR guidelines for the transfer of human pluripotent stem cells and their direct derivatives into animal hosts.

The newly revised 2021 ISSCR Guidelines for Stem Cell Research and Clinical Translation includes scientific and ethical guidance for the transfer of human pluripotent stem cells and their direct derivatives into animal models. In this white paper, the ISSCR subcommittee that drafted these guidelines for research involving the use of nonhuman embryos and postnatal animals explains and summarizes their recommendations.