Human disease modeling with induced pluripotent stem cells.

In the past few years, cellular programming, whereby virtually all human cell types, including those deep within the brain or internal organs, can potentially be produced and propagated indefinitely in culture, has opened the door to a new type of disease modeling. Importantly, many diseases or disease predispositions have genetic components that vary from person to person. Now cells from individuals can be readily reprogrammed to form pluripotent cells, and then directed to differentiate into the lineage and the cell type in which the disease manifests. Those cells will contain the genetic contribution of the donor, providing an excellent model to delve into human disease at the level of individuals and their genomic variants. To date, over fifty such disease models have been reported, and while the field is young and hurdles remain, these tools promise to inform scientists about the cause and cellular-molecular mechanisms involved in pathology, unravel the role of environmental versus hereditary factors driving disease, and provide an unprecedented tool for screening therapeutic agents that might slow or halt disease progression.