Modelling human embryogenesis: embryo-like structures spark ethical and policy debate

Area of Science:

• Developmental Biology
• Stem Cell Research
• Bioethics

Background:

• Studying human peri-implantation development is limited by inaccessibility and scarce research material.
• Pluripotent stem cells (PSCs) are used to create embryo-like structures (ELS) that mimic early embryogenesis in vitro.
• Research with human ELS presents ethical challenges due to differing views on embryo moral status and legal regulation.

Purpose of the Study:

• To provide a comprehensive overview of scientific approaches for generating mouse and human ELS from PSCs.
• To discuss future strategies for innovation in human developmental research using ELS.
• To address the ethical and policy issues surrounding human ELS research.

Main Methods:

• Searched PubMed and Web of Science databases for peer-reviewed articles and reviews.
• Used keywords such as 'stem cells', 'pluripotency', 'implantation', 'embryo models', and 'ethics'.
• Critically evaluated and discussed relevant publications up to December 2019.

Main Results:

• In vitro systems using PSCs can mimic early human developmental stages, including epiblast and trophoblast formation.
• The term 'embryo-like' necessitates re-evaluation of current embryo definitions and the concept of 'active potentiality'.
• Embryo protective directives, like the 14-day rule, require rethinking in the context of ELS research.

Conclusions:

• ELS modeling embryogenesis offers potential for understanding human development and infertility etiologies.
• ELS can recapitulate peri-implantation development but cannot develop into a fetus.
• Establishing a robust ethical and legal framework is crucial for harnessing the research potential of ELS responsibly.