stem cells breakthrough: save the embryos!

From the AP's Karen Kaplan (hat tip: C-J)...

Researchers from Japan and Wisconsin reported Tuesday that they had reprogrammed mature human cells to behave almost exactly like embryonic stem cells, a biological breakthrough that instantly recasts the field's ethical, scientific and economic landscape....The rejuvenated cells were able to grow into all the main tissue types in the body, including muscle, gut, cartilage, neurons and heart cells....

For scientists, the method offers a straightforward alternative to the tricky and still unsuccessful cloning process in which a patient's DNA is inserted into a human egg to create a cloned embryo whose stem cells theoretically could be harvested. The technique also bypasses the thorny debate over the morality of destroying embryos in the cause of alleviating human suffering....

Several key hurdles remain before the technique is ready for clinical use. The viruses employed to turn on the genes cause mutations that can lead to cancer, and one of the genes itself also has a tendency to cause tumors. But scientists said solutions to these problems were in the works. [The C-J article had some unique and relevant info from a local researcher-- Mariusz Radajczak, but I can't access it from their webpage.]...


And additional details from Gautam Naik's WSJ piece (hat tip: Linda Christiansen)...

Because the transplanted tissue would be derived from the patient's own mature cells, it would share the same genetic makeup and wouldn't be rejected by the immune system. Previously, master stem cells that can turn into all other tissue types could only be obtained from embryos, in a process that destroyed them. Moreover, to provide freshly created tissue that wouldn't be rejected by a patient's body if implanted, the embryo had to be cloned from the patient. The new method would make both cloning and embryo destruction unnecessary....

The studies have already reignited a debate in Washington about funding of human embryo research, a subject sure to be an issue in the presidential contest. They are likely to bolster the cause of those who oppose embryo research, yet accelerate the pace of stem-cell research as scientists rush to build on the new approach....

One of the new studies, published in the journal Cell, was led by Shinya Yamanaka of Kyoto University, a pioneer in the reprogramming field. A second was published in Science by researchers at the laboratory of James Thomson of the University of Wisconsin, who isolated the first human stem-cell line in 1998. Cell and Science are peer-reviewed journals.

In both cases, scientists inserted several genes into mature human cells. For reasons no one can yet fully explain, doing so reset the molecular clock -- turning mature cells into embryonic-like cells. Even among researchers, the result has a touch of science fiction. "You have this extremely strong arrow of time, and it's going completely backwards," said Dr. Thomson....

A key step, not yet taken, would be to use freshly derived tissues to treat diseases in large mammals, such as monkeys, before attempting this in humans.

There are plenty of hurdles. To ferry the genes into the cells, both teams had to use dangerous viruses as a transport mechanism. Unfortunately, the DNA of those viruses can get incorporated into the genetic structure of the cells, potentially causing cancer or other unwanted side effects. Dr. Yamanaka and others are now racing to find a benign virus that won't trigger those problems....