Challenges and Hope
Although iPSCs clearly circumvent some of the ethical and legal controversies surrounding embryonic cells, their pluripotency has yet to be completely understood or controlled, and embryonic stem cells therefore remain the gold standard for any pluripotent cell type.
Important unanswered questions include the practical issue of whether the conversion of body cells into iPSCs and the conversion of iPSCs into therapeutically relevant cell types can ever be made efficient enough for widespread use. Also unresolved is whether iPSCs retain any memory of the body cell type from which they are derived, a factor that could limit their ability to be converted into any other type of cell. We have gained some insight into the mechanisms by which a mature cell transforms into a pluripotent cell, but the process of reprogramming—how only a few genes manage to rewire the entire program of a mature cell into that of an embryonic cell—is still largely a black box.
Tackling such questions will require the continued use of embryonic cells as a reference point and will determine whether embryonic stem cells may be more effective for certain types of applications and iPSCs for others. Moreover, as truly pluripotent cells, iPSCs may raise ethical issues similar to concerns over embryonic cells because, in theory at least, iPSCs could be used to generate human embryos.
Nevertheless, from a scientific standpoint progress in the field of cellular reprogramming in recent years is truly astounding. Advances in cloning and, more recently, the discovery of
iPSCs have refuted the old dogma that the identity of cells is irreversibly locked once they have differentiated. Both techniques have raised the possibility, at least, of reprogramming the identity of a body cell from one type of tissue into that of any other tissue type just by manipulating a few genetic switches. Understanding how this rewiring works at a mechanistic level will keep researchers energized and busy for years to come.
Only time can reveal whether iPSCs or related technologies will indeed become the modern Fountain of Youth. I personally think there is a good chance they will. Certainly iPSCs will continue to influence approaches to the study and treatment of many devastating diseases and have the potential to revolutionize medicine in the 21st century as profoundly as vaccines and antibiotics did in the 20th century.
*Erratum: This sentence erroneously refers to "smooth muscular atrophy." The correct term for the disorder is "spinal muscular atrophy."
This article was originally published with the title Your Inner Healers.