Stem cell breakthrough could bring cure for genetic diseases
By Laura Shin | October 16, 2011, 7:16 PM PDT
One of the most common genetic mutations can lead to cirrhosis of the liver, and the only cure is a liver transplant, which creates its own problems: The recipient must, for the rest of his/her life, take drugs that prevent organ rejection.
But scientists have now achieved a breakthrough that means that patients with genetic diseases could someday be treated with their own cells.
The technique combines two of the most powerful medical technologies — stem cell technology and gene therapy — and could usher in a new era of personalized therapies for genetic disorders.
While the achievement marks an important step, years of trials are needed before any such treatments are available for humans.
How the therapy works
Currently, people with genetic diseases cannot be treated with their own stem cells, because those cells would also contain the genetic mutation.
But scientists at the Wellcome Trust Sanger Institute and the University of Cambridge took skin cells from a patient with metabolic liver disease, and fixed the mutation in them by excising the incorrect DNA letter and inserting the correct one.
They then turned those skin cells into liver cells that one of the lead researchers, David Lomas, said “functioned beautifully with normal secretion and function.”
They inserted the new liver cells into mice, and six weeks later, the cells were still working correctly.
Lomas told the BBC that the technique was “ridiculously hard.” He and his colleagues published their results in Nature.
Remaining hurdles
While the technique is extremely promising, a number of safety concerns remain before it can be widely used.
First, stem cells cultured in labs tend to develop mutations. In this experiment, the researchers compared the corrected line to the genome of the original skin cells and found a few extra mutations in the corrected cell lines. (However, there were many fewer mutations in the corrected lines than in the stem cells that had not been corrected.)
Also, the scientists can always screen each stem cell line to choose the ones with the fewest extra mutations.
Another concern is the cost of developing personalized therapies, although this technique could also save money because it obviates the need for a lifetime anti-organ rejection drugs.
The scientists are now aiming to work with a pharmaceutical company to eventually hold trials in people.
Photo: Human embryonice stem cells (Nissim Benvenisty/Wikimedia Commons)
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