Aug 24, 2006, 18:16 GMT
Washington - Japanese researchers have modified stem cells from adult mice into cells that have the promising characteristics of embryonic stem cells, according to research published in Thursday's issue of the journal Cell.
The announcement is the second development this week that could help scientists overcome objections to controversial research on embryonic stem cells. Embryonic stem cell research has been lauded by scientists for its potential to find cures for debilitating diseases, but critics of the technique say it essentially kills a human life because scientists must destroy an embryo to create the cells.
US researchers announced Thursday in the journal Science that they had harvested embryonic stem cells without destroying the embryo.
The Japanese researchers used four factors to cause adult stem cells to behave more like embryonic stem cells, which can grow into any type of cell in the human body. The researchers have called the new stem cells 'induced pluripotent stem cells,' or iPS, because they also have the ability to grow into any type of cell. Pluripotent is the term for cells that can grow into any type of human cell.
If the Japanese team's research proves practical, scientists could use adult human cells with characteristics of embryonic stem cells rather than harvesting stem cells from embryos.
Research on embryonic stem cells has been severely restricted in the United States and other countries. US President George W Bush in 2001 forbade the use of federal money for research on new stem cell colonies, and just recently made use of his legislative veto for the first time in six years to quash a Congressional plan that would have expanded government funds on new stem cell lines.
'Human embryonic stem cells might be used to treat a host of diseases such as Parkinson's disease, spinal cord injury and diabetes,' researcher Shinya Yamanaka of Kyoto University in Japan said. 'However, there are ethical difficulties regarding the use of human embryos, as well as the problem of tissue rejection following transplantation into patients.'
Yamanaka said he thinks the ethical questions regarding the use of embryonic stem cells could be avoided if the research on mice could be repeated with humans.
The research team focused on factors that are responsible for the development of pluripotent cells in embryos. The team worked with 24 genes and proteins that were known from previous research to be involved in the development of embryonic stem cells into various types of cells.
Scientists identified four of the 24 factors, Oct 3/4, Sox2, c-Myc and Klf4, as deciding factors. Using these factors the adult cells could be manipulated to behave like embryonic stem cells.
One of the factors, c-Myc, can not be used in humans because it is involved in the development of cancer. It is also unclear whether adult pluripotent cells can develop all the characteristics of embryonic stem cells, the researchers said
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