Human stem cells might combat Parkinson's disease in monkeys

Tokyo: Japanese neurosurgeons have found that inducing an experimental human cell therapy can lead to long-term benefits in monkeys with Parkinson's disease, a key step for initiating treatment for neurodegenerative diseases in humans.

Parkinson's disease leads to degeneration of a specific type of cells in the brain known as dopaminergic (DA) neurons. It has been reported that when the symptoms are first detected, a patient will have already lost more than half of his or her DA neurons. 

The findings reported that after transplanting the neurons prepared from human iPS cells, monkeys with Parkinson's disease symptoms showed significant improvement over two years.

Several studies have shown the transplantation of DA neurons made from foetal cells can mitigate the disease -- however, its use is controversial. 

The new study, however, showed that iPS cells made from blood or skin can be used to transplant DA neurons to treat patients.

"Our research has shown that DA neurons made from iPS cells are just as good as DA neurons made from foetal midbrain. Because iPS cells are easy to obtain, we can standardise them to only use the best iPS cells for therapy," said Ryosuke Takahashi, Professor at the Kyoto University in Japan.

For the study, appearing in the journal Nature, the team transplanted the DA neurons from different iPS cells lines -- some were from healthy donors, others from Parkinson's disease patients -- into the brains of monkeys.

The results showed that the quality of donor cells had a large effect on the DA neuron survival.

The researchers are hopeful that it can begin recruiting patients for this iPS cell-based therapy before the end of next year. 

"This study is our answer to bring iPS cells to clinical settings," Takahashi said.