Human Stem Cells Without Controversy?
University of Wisconsin stem cell scientists are reporting in the upcoming issue of Science (subscription only) that they have created pluripotent human stem cell lines by adding four genes to somatic cells that produce connective tissues. The role of the four genes, OCT4, SOX2, NANOG, and LIN28, in producing stem cells was discovered through previous experimentation with human embryonic stem cell lines.
The researchers conclude:
The human iPS [induced pluripotent stem] cells described here meet the defining criteria we originally proposed for human ES cells, with the significant exception that the iPS cells are not derived from embryos. Similar to human ES cells, human iPS cells should prove useful for studying the development and function of human tissues, for discovering and testing new drugs, and for transplantation medicine. For transplantation therapies based on these cells, with the exception of autoimmune diseases, patient-specific iPS cell lines should largely eliminate the concern of immune rejection. It is important to understand, however, that before the cells can be used in the clinic, additional work is required to avoid vectors that integrate into the genome, potentially introducing mutations at the insertion site. For drug development, human iPS cells should make it easier to generate panels of cell lines that more closely reflect the genetic diversity of a population, and should make it possible to generate cell lines from individuals predisposed to specific diseases. Human ES cells remain controversial because their derivation involves the destruction of human preimplantation embryos and iPS cells remove this concern. However, further work is needed to determine if human iPS cells differ in clinically significant ways from ES cells.
In other words, the eventual hope is that by dosing the somatic cells of patients with these four genes that physicians will be able to produce stem cells that would be perfect transplants to replace damaged, diseased or aged tissues and organs. In addition, further research using human embryonic stem cells is needed to validate these results.
