Inducible pluripotent stem cells: Not quite ready for prime time?

Abstract

Purpose of review: Inducible pluripotent stem (iPS) cells derived from somatic cells represent a novel renewable source of tissue precursors. The potential of iPS cells is considered to be at least equivalent to that of human embryonic stem cells, facilitating the treatment or cure of diseases such as diabetes mellitus, spinal cord injuries, cardiovascular disease, and neurodegenerative diseases, but with the potential added benefit of evading the adaptive immune response that otherwise limits allogeneic cell-based therapies. This review discusses recent advances in pluripotency induction and the use of iPS cells to produce differentiated cells, while highlighting roadblocks to the widespread use of this technology in the clinical arena. Recent findings: Whereas ethical and safety issues surrounding the use of human embryonic stem cells for the treatment of disease continue to be debated, use of iPS cells may be viewed as a more widely acceptable compromise. Since the first descriptions of inducible pluripotency from somatic cells, multiple laboratories have collectively made tremendous strides both in developing alternative, more clinically acceptable, induction strategies and in demonstrating the proof-of-principle that iPS cells can be differentiated into a variety of cell types to reverse mouse models of human disease. Summary: Although the prospect of using patient-specific iPS cells has much appeal from an ethical and immunologic perspective, the limitations of the technology from the standpoint of reprogramming efficiency and therapeutic safety necessitate much more in-depth research before the initiation of human clinical trials.