US scientists have harvested embryo-like stem cells from unfertilised monkey eggs, a development that could lead to an alternative source of stem cells for research into disease treatments. The researchers, based at the Wake Forest University Baptist Medical Center in North Carolina, used a process known as parthenogenesis to trigger the growth of the eggs into balls of cells. They then managed to extract stem cells, and grow them into a variety of different cells, including heart, nerve and muscle cells.
'The key is these cells were created without the union of a male and female, so in essence it is a new way of making stem cells without destroying viable embryos' said team leader Kent Vrana. The work, published in the online edition of the Proceedings of the National Academy of Sciences, builds on results reported by US firm Advanced Cell Technologies (ACT) last year. The technique exploits a natural phenomenon called parthenogenesis, in which an egg cell is stimulated to divide, without fertilisation by a sperm. Some insects, reptiles and amphibians can reproduce naturally in this way. In mammals, the resulting ball of cells is not capable of becoming an embryo, but it can produce stem cells: the body's 'master cells'. A monkey stem cell line derived in this way has now been growing in the laboratory for over two years, the researchers say. According to Vrana, the stem cells seem to be particularly good at making nerve cells, which could be a potential source of cells for treating Parkinson's disease.
If the technique could be applied to humans, the 'parthenotes' could provide an alternative to cloned human embryos as a source of tissue-matched cells to treat diseases. The cells extracted in this way appear to be very similar to their fertilised counterparts, except, says Vrana, 'they don't carry the same ethical baggage'. However, their use would be limited to women who are still producing eggs, so they would be of no help to male patients or post-menopausal women. Experiments are currently underway to find out if the cells can be transplanted back into the monkey egg donor's body without being rejected. The cells will not be genetically identical to the egg donor's cells, as genetic material is shuffled around during egg and sperm production.
Sources and References
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Unfertilsed eggs may move stem cell debate forward
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Stem cells isolated from monkey eggs continue producing variety of other cells
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Scientists develop stem cell line from unfertilized monkey egg; process could eliminate need for destruction of embryos, study says
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Stem-cell line developed without embryo
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