Incomplete reprogramming: reprogramming also faces the challenge of completeness.
Since this initial discovery, researchers have rapidly improved the techniques to generate iPSCs, creating a powerful new way to "de-differentiate" cells whose developmental fates had been previously assumed to be determined. Using the techniques described in this article, researchers are now generating myriad disease-specific iPSCs.
Thomson et al. Although additional research is needed, iPSCs are already useful tools for drug development and modeling of diseases, and scientists hope to use them in transplantation medicine. These second-generation iPSCs were derived from mouse fibroblasts by retroviral-mediated expression of the same four transcription factors Oct4, Sox2, cMyc, Klf4.
A more recent study on motor functional recovery after spinal cord injuries in mice showed that after human-induced pluripotent stem cells were transplanted into the mice, the cells differentiated into three neural lineages in the spinal cord. She quickly switched to iPS cells, and eventually began to collaborate with Yamanaka.
The presence of catecholamine -associated enzymes may indicate that iPSCs, like hESCs, may be differentiable into dopaminergic neurons.