Parkinson’s stem cell breakthrough Miodrag Stojkovic/Science Photo Library

MONKEYS with a Parkinson’s-like disease have been successfully treated with stem cells that improved their movement for up to two years after transplant. A similar trial is now being prepared for people.

Parkinson’s destroys dopamine-producing cells in the brain, leading to tremors and difficulty moving. Previous experiments using stem cells from embryos have shown promise in replacing lost cells, but the use of these is controversial.

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Jun Takahashi at Kyoto University, Japan, and colleagues wondered whether they could treat monkeys with a disease like Parkinson’s using induced pluripotent stem cells, which are made by coaxing blood or skin cells into becoming stem cells.


The team generated stem cells from three people with Parkinson’s and four without the disease. They then transformed these into dopamine-producing brain cells.

All the monkeys who received injections of these cells showed a 40 to 55 per cent improvement in their movements, matching results from previous experiments with embryonic stem cells. Monkeys who had a control injection minus the cells didn’t improve (Nature, DOI: 10.1038/nature23664).

Stem cells from people with and without Parkinson’s were equally effective. “The monkeys became more active… and showed less tremor,” says Takahashi. “Their movements became smoother.”

After the transplant, the monkeys were given immunosuppressive drugs to prevent the new cells from being rejected and observed for up to two years. No serious side effects appeared during this time.

This study shows that the stem cells behave as you would like them to and they appear safe, says Roger Barker of the University of Cambridge. “All of which gives one greater confidence in moving to human studies.”

This article appeared in print under the headline “Parkinson’s stem cell breakthrough”