Researchers have reported success in creating embryonic stem cell (ES) lines from cloned Rhesus monkey embryos, bringing the possibility of human therapeutic cloning closer.
Dr Shoukhrat Mitalipov, of the Oregon National Primate Research Centre, announced his success - which was achieved through a modified SCNT (somatic cell nuclear transfer) process - at the International Society for Stem Cell Research meeting in Cairns. The procedure involved the removal of an egg cell nucleus, which was then replaced with the nucleus of a body cell, in this case that of a 10-year old Rhesus monkey. The egg was then encouraged to grow into an embryo, from which two ES cell lines were generated.
Dr Mitalipov's success gives hope that scientists may be able to produce human ES cells from cloned adult body cells, which would not carry the risk of rejection by the patient from whom the donor cell nuclei are taken. This could mean the possibility of therapeutic or regenerative cloning helping to treat diseases including multiple sclerosis and spinal problems.
Mitalipov's lines have passed the initial tests indicating they are ES cell lines, and experts are optimistic, although they cannot properly judge the results until the research is published. Professor Alan Trounson, director of the Monash Immunology and Stem Cell Laboratories at Monash University, said 'it's exciting, because it looks terrific'. He emphasised the importance of the findings; 'it is important to have this, to know that we can do this, because it may result in a lot of new cell lines that can help us understand some complex diseases'.
However, some scientists have remained sceptical, arguing that not all of the required tests had yet been carried out on the newly created lines. Irving Weissman, from Stanford University in Palo Alto, California, pointed out that a key feature that had not yet been tested was whether the cells could be incorporated into tissue when mixed with a normal embryo, which is the case with ES cells.
Mitalipov attributed his breakthrough to a modification of the standard SCNT process. Instead of the traditional method of using dye to stain the egg nucleus, followed by visualisation by ultraviolet light, the team illuminated the eggs with polarised light. Mitalipov believed that the use of the dye might have damaged fundamental reprogramming factors. Some scientists remain to be convinced of the success. Robert Lanza of Advanced Cell Technology in Massachusetts said that 'there has to be more to this approach than using the polar scope'.
Sources and References
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Stem cells created from cloned monkey cells
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Researchers Derive Stem Cells From Monkeys
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Stem cells from cloned primates
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