Sample Quiz Question on Embryogenesis
Here is a clinically relevant multiple-choice question on human embryogenesis:
Question Stem
A research team is developing stem cell-based embryo models to study early human development. They create a 3D model that contains epiblast derivatives and develops amnion-like structures, but lacks trophoblast and hypoblast components. According to current ISSCR guidelines, how should this model be classified?
Answer Choices
A. Integrated embryo model requiring specialized ethical review (Category 2)
B. Non-integrated embryo model that is reportable but not subject to further review (Category 1B)
C. Prohibited research activity (Category 3)
D. Equivalent to a human blastocyst requiring 14-day rule restrictions
E. Trophoblast organoid requiring standard oversight (Category 1A)
Correct Answer
B. Non-integrated embryo model that is reportable but not subject to further review (Category 1B)
Explanation
Non-integrated embryo models mimic only specific aspects or tissues of human embryo development and often lack associated extra-embryonic membranes, making them reportable but not normally subject to further specialized review 1.
The described model contains only epiblast derivatives (amnion-like structures) without trophoblast or hypoblast components, fitting the definition of a non-integrated model such as gastruloids or PASE (post-implantation amniotic sac embryoid) 1.
Integrated embryo models, in contrast, contain relevant embryonic AND extra-embryonic cell types (epiblast, hypoblast, and trophoblast) and require full specialized review under Category 2 1.
Recent evidence demonstrates that incorporation of trophoblast derivatives is not a prerequisite for organized development of embryo-like structures in all stem cell-based embryo models, but the presence of all three founding lineages determines the classification 1.
These models are valuable for studying gastrulation, body axis formation, and somitogenesis without the ethical complexities of integrated models 1.