Stem cell therapy for Parkinson's disease

Sufferers of Parkinson’s disease may soon be enjoying improved movement thanks to a team of researchers from Kyoto University, Japan, and some crab-eating macaques.

The Japanese researchers have shown that the implantation of dopaminergic neurons derived from human induced pluripotent stem cells can restore nerve function and improve movement in primates suffering from the monkey equivalent of PD.

Induced pluripotent stem cells (iPSCs) have shown to be a promising source for cell-based therapy in a wide range of applications. The Japanese team, led by Jun Takahashi, have had considerable success with human iPSC derived dopaminergic progenitor cells in a primate model of PD (Macaca fascicularis) treated with the neurotoxin MPTP.

Neurons developed from human stem cells drew minimal immune responses from the monkey’s brains and failed to form any tumours across the course of the two-year study. These iPSCs are reprogrammed adult cells with a considerable range of potential differentiation. In patients with PD, dopaminergic neurons are damaged and this study has shown that iPSCs are a promising source for replacing those damaged nerve cells. This approach may also be useful in the brains of patients with other neurological diseases.

While overall survival of the implanted cells was good, it did vary from subject to subject, allowing the scientists to identify genetic signatures that could be useful in selecting the best cell lines when this method is taken to clinical trial. The authors are optimistic that these results can lead to the development of cell-based treatments for neurological diseases. This research was published in Nature.

Takahashi and colleagues have also published a related paper in Nature Communications, outlining their approach to improving the survival of iPSC-derived neurons after transplantation. A group of proteins which have a role in eliciting immune responses, known as the major histocompatibility complex (MHC), can help improve graft survival if they are matched with the derived neurons, reducing immune response. When combined with immunosuppressive drugs, the required dose and duration is much reduced.

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