Progress toward the clinical application of patient-specific pluripotent stem cells

Induced pluripotent stem (iPS) cells are generated by epigenetic reprogramming of somatic cells through the exogenous expression of transcription factors. These cells, just like embryonic stem cells, are likely to have a major impact on regenerative medicine, because they self-renew and retain the potential to be differentiated into all cell types of the human body. In this Review, we describe the current state of iPS cell technology, including approaches by which they are generated and what is known about their biology, and discuss the potential applications of these cells for disease modeling, drug discovery, and, eventually, cell replacement therapy. Cell Reprogramming Method of Timeline Efficiency Genomic Genomic Refs. type factors delivery (wk) integration integration removed Mouse MEFs O,S,K,M Retroviral vectors 2-3 0.01%-0.050% Yes No 10, 12-15 MEFs O,S,K Retroviral vectors 3-4 0.001%-0.01% Yes No 56, 65, 98 Hepatocytes and O,S,K,M or O,S,K Retroviral vectors 2-3 0.5%-3% Yes No 46 stomach cells Neural stem cells O,S,K,M or O,S,K Retroviral vectors 1-4 0.1%-5% Yes No 48, 99 or O,K,M or O,S,M Neural stem cells O,K or O,M or O Retroviral vectors 2-4 0.1%-0.2% Yes No 32, 100 B lymphocytes O,S,K,M Lentiviral vectors A 2-3 0.01%-0.1% Yes No 34 Hepatocytes O,S,K,M Adenoviral vectors 4-5 0.0001%-0.001% No -29 MEFs O,S,K,M Plasmid transient transfection 3-4 0.0001%-0.