Tuesday , October 19 2021

Stem cells grafted onto a patient's brain



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Japanese researchers have injected so-called "iPS" stem cells into the brain of a patient with Parkinson's disease. This clinical trial aims to test whether these cells can regenerate dopamine neurons and alleviate symptoms.

The team atKyoto University injected 2.4 million of these pluripotent cells, capable of giving any type of cell in the left part brainduring a three-hour operation last month. The man, in his early 50s, was well tolerated and kept under surveillance for two years, Kyoto University said in a statement.

If no problem emerges in the next six months, researchers will deploy another 2.4 million cells, this time in the right part of the patient's brain. These iPS cells from healthy donors are expected to grow neurons dopamine, a neurotransmitter involved in motor control.

In July, Kyoto University announced the completion of this clinical trial with seven participants aged 50-69 years. "I greet patients for their courageous and determined participation", commented Professor Jun Takahashi, quoted on Friday by NHK's public television channel.

Pluripotent cells to generate new neurons

O Parkinson's disease is marked by the degeneration of dopaminergic neurons and results in symptoms which progressively worsen, such as tremors, limb stiffness and decreased body movements. It affects more than ten million people around the world, according to Foundation of Parkinson's Disease USA. Therapies currently available "It improves symptoms without delaying the progression of the disease"explains the foundation.

This test follows an experiment carried out on monkeys with stem cells of human origin that have improved the ability to make movements in primates suffering from Parkinson's disease, according to a study published at the end of August 2017 in the scientific journal nature. The survival of the grafted cells by injection into the primate brain was observed for two years, without tumor.

O induced pluripotent stem cells (iPS for induced pluripotent stem cells) are adult cells brought back to the almost embryonic state, causing them to express four genes (usually inactive in adult cells). This genetic manipulation gives them the ability to produce any kind of cell (pluripotency) according to the body location where they are then transplanted. The use of iPS cells presents no fundamental ethical problems, as opposed to stem cells withdrawn embryos human beings.

What to remember

  • Scientists at Kyoto University injected 2.4 million pluripotent cells into a patient's brain.
  • These cells from healthy donors will need to regenerate dopamine neurons.
  • In total, the clinical trial should involve seven patients.

Parkinson: Stem cells reduce disease in monkeys

Article from Tokyo – AFP published on February 25, 2012

Monkeys developing the equivalent of Parkinson's disease showed an improvement in their symptoms after the injection into their brains of human stem cells. The technique could be tested in humans from 2015.

Monkeys suffering from Parkinson's disease have made significant progress after implanting human stem cells into their brains, Japanese researchers said on Wednesday.

Four monkeys whose limbs moved spasmodically (a common symptom of syndrome in Parkinson'sAnd who fought to control their bodies showed signs of improvement three months after the operation, said Jun Takahashi, a professor at the University of Washington.Kyoto University, one of the authors of the study published in Journal of Parkinson's Disease.

Six months after the transplantThe four primates tested were again able to walk in their cage, he added.

Jun Takahashi stated that, at the time of implementation, 35% of stem cells were dopaminergic neurons, and about a tenth of them were still alive a year later. In order to improve the effectiveness of treatment, he would like to increase that survival rate to 70%. He hopes to be able to conduct this experiment in humans by 2015. " We must first increase the number of dopaminergic neurons to to implantin order to reduce the risk of tumor " postoperative, He explained.

Induced pluripotent stem cells in humans

In this ape experience, Jun Takahashi and his team used embryonic stem cellsbut in the case of medical experience, the researchers think they are using induced pluripotent stem cells (IPSCs), created by the implantation of four types of genes in human skin cells for reprogramming. These induced iPSCs thus generated return almost to the embryonic (undifferentiated) stage.

The use of embryonic stem cells, which is considered very promising by many scientists, opposes. Religious groups consider the culture of these cells unethical, emphasizing that destruction of an embryo. In Japan, however, nothing prohibits the use of these cells for scientific research.

O Parkinson's disease is one of the main neurodegenerative diseasesafter Alzheimer's disease. It is also one of the most common causes of motor incapacity after accidents cerebrovascular diseases.

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