Nerve cells grown from new-style stem cells

Ordinary skin cells taken from patients with a fatal and incurable nerve disease have been transformed into nerve cells in a first step toward treating them, US researchers reported. They transformed the cells from two patients with amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, into motor neurons—the cells that waste away and die in ALS. There is no immediate medical use for the cells, taken from two sisters aged 82 and 89, the researchers reported in the journal Science.

"Now we can make limitless supplies of the cells that die in this awful disease. This will allow us to study these neurons and ALS, in a lab dish, and figure out what's happening in the disease process," said Dr Kevin Eggan of Harvard Medical School in Boston, who helped lead the study. "We can generate hundreds of millions of motor neurons that are genetically identical to a patient's own neurons," added Chris Henderson of Columbia University in New York, who also worked on the study. "This will be an immense help as we try to uncover the mechanisms behind this disease and screen for drugs that can prolong life."

There is no cure for ALS. The causes are not clear and it kills by gradually paralysing patients. About 120,000 new cases are diagnosed each year, according to the International Alliance of ALS. "It is our lack of understanding of that disease process which is preventing us from developing more effective treatments," Henderson said. "There is no way we could go to an ALS patient and take a sample of their motor neurons," he added, because the affected cells are in the spinal cord.

Eggan and Henderson hope to grow and study these motor neurons and see if they can re-create the disease in a lab dish–and then try out various drugs to treat it. The two patients have a mild form of ALS caused by a single genetic mutation, and all of the cells in their body carry that mutation. The experiment helps fulfil one of the promises of embryonic stem cell research, Eggan said. The hope of the controversial research has always been to figure out ways to make ordinary cells into customised scientific experiments, and into tailor—made medical treatments.

Last year several teams of researchers reported they had genetically engineered ordinary skin cells to act like embryonic stem cells—the master cells of the body, which have the ability to morph into any cell or tissue type. Eggan said that this does not mean it is no longer necessary to use the controversial methods to get real embryonic stem cells by using human embryos from fertility clinics or by using cloning technology. For one thing, they used viruses to carry in the four genes that transformed the skin cells. These viruses integrate into the cells, making them far too dangerous to use in people, Eggan said. For another, the genetic defect that causes ALS would have to be corrected before the cells could be used in any treatment, the researchers said. Embryonic stem cell research is what allowed them to figure out how to do every step in their experiment, Eggan added. And if this one fails, the researchers will have to return to true embryonic stem cells.

Posted by Editor at September 15, 2008 12:58 PM

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