Create your own heart, using your own skin
June 6th, 2007Shinya Yamanaka of Kyoto University has created a new technique that by inserting four genes into a mouse skin cell reprograms it so it appears to be an embryonic stem cell. This technique has already been verified by other teams of scientists.
This is huge news.
This means that rather than have a controversy over extracting stem cells from fetuses, and rather than have issues over the scarcity of organs for transplantation, it’s likely a matter of time before you will be able to grow a replacement body part from your own skin cells.
As the NY Times reports:
If the technique can be adapted to human cells, it would let scientists use a patient’s skin cell to generate new heart, liver or kidney cells that might be transplantable and would not be rejected by the patient’s immune system. …
The technique is much easier to apply than nuclear transfer, does not involve the expensive and controversial use of human eggs, and should avoid all or almost all of the ethical criticism directed at the use of embryonic stem cells. …
It raises no serious moral problem, because it creates embryonic-like stem cells without creating, harming or destroying human lives at any stage, said Richard Doerflinger, a spokesman on stem cell issues for the United States Conference of Catholic Bishops. …
Ever since the creation of Dolly, the first cloned mammal, scientists have sought to lay hands on the mysterious chemicals with which an egg will reprogram a mature cell nucleus injected into it and set the cell on the same path of embryonic development as when egg and sperm combine. …
Last year Dr. Yamanaka and his colleague Kazutoshi Takahashi, both at Kyoto University, published a remarkable report relating how they had guessed at 24 genes that seemed responsible for maintaining
pluripotency in mouse embryonic stem cells. …When they inserted all 24 genes into mouse skin cells, the cells showed signs of pluripotency. The Kyoto team then subtracted genes one by one until they had a set of four genes that were essential. The genes are inserted into viruses that infect the cell and become active as the virus replicates. The skin cell’s own copies of these genes are repressed since they would interfere with its function. “We were very surprised that just four genes are sufficient to reprogram the skin cells,” Dr. Yamanaka said. …
Dr. Yamanaka’s report riveted the attention of biologists elsewhere. Two teams set out to repeat and extend his findings, one led by Rudolf Jaenisch of the Whitehead Institute and the other by Kathrin Plath of the University of California, Los Angeles, and Konrad Hochedlinger of the Massachusetts General Hospital. Dr. Yamanaka, too, set about refining his work.
In articles being published in Nature and a new journal, Cell-Stem Cell, the three teams show that injection of the four genes identified by Dr. Yamanaka can make mouse cells revert to cells that are indistinguishable from embryonic stem cells. …
An immediate issue is whether the technique can be reinvented for human cells. One problem is that the mice have to be interbred. Another is that the cells must be infected with the gene-carrying virus, which is not ideal for cells to be used in therapy. A third issue is that two of the genes in the recipe can cause cancer. Indeed 20 percent of Dr. Yamanaka’s mice died of the disease. Nonetheless, several biologists expressed confidence that all these difficulties will be sidestepped somehow. …
Repairing the body with its own cells should in principle be a superior form of medicine to the surgeon’s knife and the oncologists’ poisons.
http://www.nytimes.com/2007/06/06/science/06cnd-cell.html?_r=1&hp=&pagewanted=all
Medicine will likely never be the same.