A team of Japanese scientists has announced that they have transplanted 2.4 million “iPS” stem cells into the brain of a patient suffering from Parkinson’s disease. This trial, the first of its kind in the world, aims to create new neurons that produce dopamine, a key neurotransmitter involved in motor control, which is lacking in this disease.
This is a world first that gives hope to people with Parkinson’s disease. This Friday, November 9, researchers from Kyoto University in Japan said in a press release that they had succeeded in transplanting 2.4 million iPS stem cells into the left brain of a patient suffering from Parkinson’s disease (for “induced pluripotent stem cells” or, in French, induced pluripotent stem cells).
The operation, which took place last month, lasted three hours, the medical team said. The patient, a man in his fifties, tolerated the treatment well. He will now be monitored for two years. If no problem appears within six months, the doctors will again implant 2.4 million additional stem cells, this time in the right part of the patient’s brain.
Pluripotent stem cells
The second most common neurodegenerative disease of the nervous system after Alzheimer’s disease, Parkinson’s disease affects approximately 200,000 people in France and more than one million in Europe: 8,000 new cases are reported each year in France. According to the American Parkinson’s Disease Foundation, the world has 10 million Parkinson’s patients.
Characterized by a progressive loss of neurons in the gray nuclei of the brain that secrete dopamine, Parkinson’s disease causes a progressive loss of control of movements and the appearance of other motor symptoms such as tremors at rest and rigidity of the limbs. Currently, available treatments that provide dopamine or simulate its action “improve symptoms, but do not slow disease progression,” says the Parkinson’s Disease Foundation.
This new treatment on iPS stem cells from healthy donors therefore offers new hope to patients. Indeed, the latter have the particularity of being pluripotent: by being transplanted into the brain, in a given place, they should be able to transform into neurons that produce dopamine, a neurotransmitter involved in motor control.
A clinical trial on seven patients announced
This successful test by Japanese scientists will probably not be the last. Last July, Kyoto University announced that a clinical trial would be launched with seven participants aged 50 to 69. “I salute the patients for their courageous and determined participation,” commented Professor Jun Takahashi, quoted Friday by the public television channel NHK.
This clinical trial itself follows an experiment carried out on monkeys with stem cells of human origin, and reported in an article in the journal Nature in August 2017. According to the researchers, this transplantation has improved the ability of primates suffering from a form of Parkinson’s to make movements. The survival of the grafted cells, by injection into the brain of primates, was observed for two years, without any appearance of tumour.
However, we must be right because it is not enough that the transplant goes well for it to be functional. Evidenced by stem cell transplants in the heart, whose experiments have been taking place for years with extremely modest functional results. Not all problems will be solved with a transplant, but hope advances researchers and medicine.
.
