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Researchers at Children's Hospital in Boston have announced progress in techniques for transforming ordinary skin cells into functioning stem cells, without the need to harvest stem cells from human embryos.

Transforming ordinary skin cells into functioning stem cells

Stem cells are embryonic cells with the potential to become any kind of human tissue. The most obvious source of stem cells is the human embryo, rapidly multiplying into a mass of cells before tissues and organs form. Many religious people, however, decry the destruction of a potential human life to harvest cells for the creation of tissues and organs for others.

With the new technology, anyone can be his or her own source of stem cells. Skin cells are treated so that the cell becomes an induced pluripotent stem cell, or iPS. These laboratory-created stem cells can then be treated so that they form cells of a particular kind of tissue, and the tissue can be grown in a kind of shaping mold or literally sprayed like printer ink in layers to make a new organ.

This technology is not new. It's been around since 2005, when American researchers were severely limited by restrictions on the use of stem cells by the Bush administration. The first generation of this technology for transforming skin cells into stem cells, however, exposed the recipients of the stem cells to a high risk of cancer, which can be understood in part as a mature cell trying to get back to the stem cell state after changes in its DNA.

No need for DNA modification

The newly announced second generation of skin cell to stem cell technology does not require modification of DNA. Instead, it relies on changes to RNA. The RNA of the skin cell is activated to produce "reprogramming proteins" that allow the cell to gain the power of transformation into other tissues. In the method developed at Children's Hospital in Boston, the researchers are able to mass produce stem cells that do not require treatment for transplant rejection, because they have exactly identical DNA, having been derived from the recipient's own skin.

The new method of creating stem cells has enormous advantages over the therapeutic technology of just ten years ago, using viruses to carry snippets of DNA into cells with hopes of changing them to correct a disease condition. The problem of using viruses to change human DNA in living people, of course, was getting rid of the viruses once they had done their work. And the limitation of even this newly announced technology seems to be that skin cells must be turned into stem cells, the stem cells grown in the lab to make the desired tissue, and the tissue transplanted back into the person who needs it.

The next generation of stem cell technology, however, may utilize "homing proteins" to direct the activated RNA to the cells already in the body that need to be transformed. In this way there is no need for viruses, no need for surgery, and no chance of rejection. This level of stem cell technology, however, is at least a few years away from clinical testing.

  • Highly Efficient Reprogramming to Pluripotency and Directed Differentiation of Human Cells with Synthetic Modified mRNA. Luigi Warren, Philip D. Manos, Tim Ahfeldt, Yuin-Han Loh, Hu Li, Frank Lau, Wataru Ebina, Pankaj K. Mandal, Zachary D. Smith, Alexander Meissner, George Q. Daley, Andrew S. Brack, James J. Collins, Chad Cowan, Thorsten M. Schlaeger, and Derrick J. Rossi 10.1016/j.stem.2010.08.012.