Friday, June 22, 2007
embryonic stemcells
Summary and Comment
Creation of Embryonic Stem Cells Without Using Embryos, in Mice
New technique could circumvent the ethical debates surrounding stem cell biology.
Scientists used to believe that a differentiated cell could never return to a less mature state, much less revert into an embryonic state. Yet, nuclear transfer experiments in animals have shown that the nucleus of a differentiated adult cell can be reprogrammed by the egg into which it is inserted, creating an early embryo containing embryonic stem cells. However, the creation of a human embryo by this technique has not been accomplished and would raise ethical issues for some.
Several research groups now report that they have transformed fibroblasts from the skin of adult mice into cells with all the qualities and potential of embryonic stem cells. Investigators used viral vectors to insert four genes into the fibroblasts. The genes reprogrammed the cell to become an embryonic stem cell, without involving the creation of an embryo. Two of the genes are oncogenes.
Comment: If the same technique can be made to work in humans, genetically identical embryonic stem cells could be created for anybody, avoiding both immune rejection and ethical issues. Investigators will now try to replicate these results in human cells and to avoid two potential problems in humans: the cancer-causing potential of oncogenes and the use of viruses to introduce the necessary reprogramming genes. No one can predict whether this work will be successful or how long success may take. But no one would have predicted that this breakthrough in mice would come as quickly as it did.
— Anthony L. Komaroff, MD
Published in Journal Watch General Medicine June 21, 2007
Creation of Embryonic Stem Cells Without Using Embryos, in Mice
New technique could circumvent the ethical debates surrounding stem cell biology.
Scientists used to believe that a differentiated cell could never return to a less mature state, much less revert into an embryonic state. Yet, nuclear transfer experiments in animals have shown that the nucleus of a differentiated adult cell can be reprogrammed by the egg into which it is inserted, creating an early embryo containing embryonic stem cells. However, the creation of a human embryo by this technique has not been accomplished and would raise ethical issues for some.
Several research groups now report that they have transformed fibroblasts from the skin of adult mice into cells with all the qualities and potential of embryonic stem cells. Investigators used viral vectors to insert four genes into the fibroblasts. The genes reprogrammed the cell to become an embryonic stem cell, without involving the creation of an embryo. Two of the genes are oncogenes.
Comment: If the same technique can be made to work in humans, genetically identical embryonic stem cells could be created for anybody, avoiding both immune rejection and ethical issues. Investigators will now try to replicate these results in human cells and to avoid two potential problems in humans: the cancer-causing potential of oncogenes and the use of viruses to introduce the necessary reprogramming genes. No one can predict whether this work will be successful or how long success may take. But no one would have predicted that this breakthrough in mice would come as quickly as it did.
— Anthony L. Komaroff, MD
Published in Journal Watch General Medicine June 21, 2007
# posted by roodbont @ 2:04 AM 
