19 February 2009
A new study has demonstrated that animal oocytes lack the capacity to fully reprogramme adult human cells, delivering a blow to many in the scientific industry. It had been hoped that substitute animal oocytes could help generate patient-specific stem cells for therapeutic applications.
Since the cloning of Dolly the Sheep more than a decade ago, somatic cell nuclear transfer (SCNT) has been considered a promising method for creating personalized stem cells. Because of the shortage of human donor eggs, cows, rabbits and other animals have long been considered a possible surrogate source of eggs. Although previous reports have documented the formation of cloned embryos using both human and animal eggs, to date there have been no data indicating whether ? and to what extent ? the donor DNA was reprogrammed.
The study, published in Cloning and Stem Cells, looked at the reprogramming of human cells using eggs obtained from human and animal sources, and shows that the donor DNA in the cloned human embryo is extensively regrogrammed through up-regulation ('turning on' of genes) with similar expression patterns to normal human embryos. Nearly all of the key differentially expressed genes were activated in the human clones, whereas the majority of these genes were down regulated or silenced in the human?animal hybrids.
Robert Lanza, Chief Scientific Officer at Advanced Cell technology Inc. and senior author of the study, says: "These data call into question the potential use of animal egg sources to generate patient-specific stem cells."
This very important paper suggest that livestock oocytes are extremely unlikely to be suitable as recipients for use in human nuclear transfer," says Ian Wilmut, Editor in Chief of Cloning and Stem Cells and Director of the Centre for Regenerative Medicine. "This is very disappointing because it would mean that production of patient-specific stem cells by this means would be impracticable."
www.liebertpub.com
http://www.ptemag.com/pharmtecheurope/Latest+News/A-blow-for-animal-oocytes-and-stem-cells/ArticleStandard/Article/detail/581348?contextCategoryId=45298
A new study has demonstrated that animal oocytes lack the capacity to fully reprogramme adult human cells, delivering a blow to many in the scientific industry. It had been hoped that substitute animal oocytes could help generate patient-specific stem cells for therapeutic applications.
Since the cloning of Dolly the Sheep more than a decade ago, somatic cell nuclear transfer (SCNT) has been considered a promising method for creating personalized stem cells. Because of the shortage of human donor eggs, cows, rabbits and other animals have long been considered a possible surrogate source of eggs. Although previous reports have documented the formation of cloned embryos using both human and animal eggs, to date there have been no data indicating whether ? and to what extent ? the donor DNA was reprogrammed.
The study, published in Cloning and Stem Cells, looked at the reprogramming of human cells using eggs obtained from human and animal sources, and shows that the donor DNA in the cloned human embryo is extensively regrogrammed through up-regulation ('turning on' of genes) with similar expression patterns to normal human embryos. Nearly all of the key differentially expressed genes were activated in the human clones, whereas the majority of these genes were down regulated or silenced in the human?animal hybrids.
Robert Lanza, Chief Scientific Officer at Advanced Cell technology Inc. and senior author of the study, says: "These data call into question the potential use of animal egg sources to generate patient-specific stem cells."
This very important paper suggest that livestock oocytes are extremely unlikely to be suitable as recipients for use in human nuclear transfer," says Ian Wilmut, Editor in Chief of Cloning and Stem Cells and Director of the Centre for Regenerative Medicine. "This is very disappointing because it would mean that production of patient-specific stem cells by this means would be impracticable."
www.liebertpub.com
http://www.ptemag.com/pharmtecheurope/Latest+News/A-blow-for-animal-oocytes-and-stem-cells/ArticleStandard/Article/detail/581348?contextCategoryId=45298