The Future of iPS Cell Transplantation in Parkinson’s Disease
As a movement disorder specialist, I have been asked by a number of people with Parkinson’s (PwP) whether iPS cells1 will find their place in PD treatment. The answer is definitely ‘Yes’, but I always say to them that there needs to be another twist or turn before being used as a standard therapy. Of course, uncontrolled proliferation or transformation into cancer cells has been the major concern, but that has been handled quite safely at least in a monkey model of PD. The biggest concern is the control of dopamine release by these cells. In the era of fetal adrenal transplantations, there have been unfortunate cases of uncontrollable releases of dopamine, which caused severe incapacitating dyskinesia. We are still seeking electronic devices that are implantable with the cells titrating the amount of dopamine released by the cells. In healthy brains, dopamine concentration in the striatum is intricately monitored by medium spiny neurons in a special compartment, known as striosome. These cells act as a sensor of dopamine, since they are stimulated by dopamine released by nigrostriatal neurons, and in turn send feedback inhibition to the latter. Dopamine itself needs changes in concentration, depending upon the needs for the movements. By the same token, continuous dopamine stimulation through Duodopa is not a perfect solution. I would love to see scientists and people with PD interested in these projects, and to discuss more about them at WPC 2019 in Kyoto.
1. iPS cells: Induced Pluripotent Stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from adult cells.
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Ryuji Kaji MD, PhD is on the Local Organizing Committee for the Fifth World Parkinson Congress and he served on the Program Committee for the Fourth World Parkinson Congress. He presented at the Third World Parkinson Congress in Montreal, Canada and the Fourth World Parkinson Congress in Portland, Oregon, USA. He is currently Professor and Chairman of the Department of Neurology at Tokushima University, Graduate School of Medicine, Tokushima, Japan.
Ideas and opinions expressed in this post reflect that of the author(s) solely. They do not reflect the opinions or positions of the World Parkinson Coalition®