One of the last steps before treating patients with an experimental cell therapy for the brain is confirmation that the therapy works in monkeys. Today, scientists at the Center for iPS Cell Research and Application (CiRA), Kyoto University, Japan, report monkeys with Parkinson’s disease symptoms show significant improvement over two years after being transplanted neurons prepared from human iPS cells. The study, which can be read in Nature, is an expected final step before the first iPS cell-based therapy for neurodegenerative diseases.
Parkinson’s disease degenerates a specific type of cells in the brain known as dopaminergic (DA) neurons. It has been reported that when symptoms are first detected, a patient will have already lost more than half of his or her DA neurons. Several studies have shown the transplantation of DA neurons made from fetal cells can mitigate the disease. The use of fetal tissues is controversial, however. On the other hand, iPS cells can be made from blood or skin, which is why Professor Takahashi, who is also a neurosurgeon specializing in Parkinson’s disease, plans to use DA neurons made from iPS cells to treat patients.
“Our research has shown that DA neurons made from iPS cells are just as good as DA neurons made from fetal midbrain. Because iPS cells are easy to obtain, we can standardize them to only use the best iPS cells for therapy, ” he said.
To test the safety and effectiveness of DA neurons made from human iPS cells, Tetsuhiro Kikuchi, a neurosurgeon working in the Takahashi lab, transplanted the cells into the brains of monkeys.
“We made DA neurons from different iPS cells lines. Some were made with iPS cells from healthy donors. Others were made from Parkinson’s disease patients,” said Kikuchi, who added that the differentiation method used to convert iPS cells into neurons is suitable for clinical trials.