Japan stem-cell trial stirs envy

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Masayo Takahashi is the first to implant tissue derived from induced pluripotent stem cells into a person.

Its awesome, its amazing, Im thrilled, Ive been waiting for this, says Jeanne Loring, a stem-cell biologist at the Scripps Research Institute in La Jolla, California. She is one of several researchers around the world to welcome the news that a Japanese woman with visual impairment had become the first person to receive a therapy derived from stem cells known as induced pluripotent stem (iPS) cells.

A lot rides on this trial. If the procedure proves safe, it could soften the stance of regulatory bodies in other nations towards human trials of iPS cells, and it could pave the way for treatments for other conditions, such as Parkinsons disease and diabetes. It could also cement Japan, recently plagued by a stem-cell scandal, as a frontrunner in iPS-cell research.

Pioneered in 2006 by Shinya Yamanaka, now director of the Center for iPS Cell Research and Applications at Kyoto University, iPS cells are created by inserting certain genes into the DNA of adult cells to reprogram the cells back to an embryonic-like state. The cells can then be turned into almost any tissue type, much as embryonic stem cells can. But because iPS cells can be derived from a patients own tissue, the hope is that they will dodge some of the controversial aspects and safety concerns of those derived from embryos.

In 2012, Yamanaka received a Nobel prize for his work, and the field has now matured, with teams across the world champing at the bit to test therapies based on iPS cells in people. Loring, for example, uses the cells to create dopamine-producing neurons as a potential therapy for Parkinsons disease, and says that she will start clinical trials as soon as the US Food and Drug Administration (FDA) gives the go-ahead.

Still, tissues made from iPS cells carry their own concerns, and that had stopped any country from approving them for a clinical trial. The bodys immune system could attack them, or they might contain some cells that are still in the pluripotent state and cause cancerous growths although Loring points out that this has not happened with human trials of therapies based on embryonic stem cells, for which the same concerns would apply.

In July 2013, however, Japans regulatory authorities gave the go-ahead for a team led by ophthalmologist Masayo Takahashi at the RIKEN Center for Developmental Biology (CDB) in Kobe to collect cells to be used in a clinical iPS-cell pilot study.

Her team took skin cells from the first patient, a woman in her seventies who had retinal damage owing to a condition known as age-related macular degeneration. The researchers then reprogrammed the skin cells into iPS cells and coaxed the unspecialized cells into becoming retinal tissue. On 8September, Takahashi provided evidence that those cells were genetically stable and safe, a prerequisite for them to be transplanted into the eye. The procedure took place four days later, and RIKEN has reported that the patient experienced no serious side effects.

In this instance, the womans vision is unlikely to improve. However, researchers around the world are watching to see whether the cells stop the retina from deteriorating further and whether any side effects develop. Should the woman experience serious consequences, iPS-cell research could be set back years, much as gene therapy was in 1999 when a patient died in a trial that attempted to use a modified gene to correct a type of liver disease. That wakes me up at night, Loring admits.

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Japan stem-cell trial stirs envy