Observation of Cultured Cells

Interest in stem cells has heightened because of recent improvements in methods for propagation of human cells in culture and their promise for regenerative medicine. Cell culture techniques are pivotal for expansion of the limited numbers of cells present in vivo and in inducing lineage commitment of progeny cells. 

The value of cultured stem cells to toxicology is in their promise as a continuous source of cells that can be induced to express a chosen cell-type-specific mature phenotype. This achievement would address two current limitations in safety testing scarcity of metabolically competent human systems and use of experimental animals. Numerous culture additives and conditions have been identified that cause commitment and partial differentiation along specific lineages, such as retinoic-acid-induced neuronal commitment of mouse embryonic stem cells. However, definition of conditions that produce fully differentiated cells with cell-type-specific function quantitatively similar to that of intact tissue remains problematic and is a high-priority research area in toxicology. 

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