Reconsidering pluripotency tests: do we still need teratoma assays?

Area of Science:

• Stem cell biology
• Developmental biology
• Bioethics

Background:

• The teratoma assay has been the standard for assessing stem cell pluripotency since 1954.
• Its scientific validity is debated due to non-physiological conditions and significant animal use.
• The rise of human induced pluripotent stem cells necessitates re-evaluation.

Purpose of the Study:

• To critically evaluate the teratoma assay for stem cell pluripotency assessment.
• To explore and advocate for alternative, ethical, and scientifically robust methods.
• To address the need for standardized in vitro and in silico assays.

Main Methods:

• Review of the historical use and scientific limitations of the teratoma assay.
• Identification and discussion of candidate alternative assays.
• Emphasis on the need for validation of alternative methods.

Main Results:

• The teratoma assay's scientific basis is questioned due to transplantation into non-physiological environments.
• Several alternative methods show promise, including directed differentiation, embryoid bodies, biomarker analysis, and epigenetic footprints.
• No single alternative is currently a fully accepted replacement.

Conclusions:

• The teratoma assay requires ethical reconsideration due to its limitations and animal usage.
• Development and validation of standardized, affordable in vitro and in silico assays are crucial.
• These alternatives are essential for the responsible advancement of stem cell research, particularly with human induced pluripotent stem cells.