On Monday, July 30, Japanese researchers announced that a first trial of treating Parkinson's disease in humans with so-called "iPS" stem cells would begin on Wednesday, August 1st. Explanations
► What is a stem cell?
A stem cell is a cell capable of duplicating to produce specialized cells. This is for example the case of embryonic stem cells, which constitute the embryo. From 5 e day after fertilization, the embryo comprises about thirty so-called "pluripotent" cells that will give all the cells of the body (muscles, skin, blood, neurons, etc.) after multiplication. and specialization, explains Inserm
Questions about stem cells
In France, these cells can be taken from supernumerary embryos after in vitro fertilization (IVF) for scientific research purposes, only for framed projects and after agreement of the couple at the origin of IVF. Such an operation destroys the embryo.
Medically, these cells give rise to much hope for "repairing" organs and tissues. It could indeed grow embryonic stem cells to differentiate into cells of the retina for example, and then apply them in a patient with visual problems. No treatment of this type has taken place in France for the moment, only a few clinical trials are in progress in the world.
Find the complete out of series of La Croix on the stakes of bioethics  ► What are different about iPS cells?
While embryonic stem cell research raises many ethical debates, iPS (induced pluripotent stem cell) alternative. It is no longer a question of taking cells from an embryo, but of returning adult cells to this pluripotent state. This discovery, developed in the late 2000s, was awarded a Nobel Prize in medicine in 2012.
In practice, an adult cell is taken from an individual, often from the skin, and then reprogrammed. injecting four genes. These genes can reactivate the immaturity of the cell, which becomes undifferentiated and therefore pluripotent. " These adult cells are as effective and much more widely used than embryonic cells ," explained Alain Privat, former unit director of Inserm and close to the Fondation Jérôme-Lejeune in The Cross in March of last year
Should we continue research on the embryo?
The advantage of this technique for possible cell therapies is that it minimizes the risk of rejection if the adult cell is taken from the same person who must then be treated. But this technique has a significant cost, about 15 000 €, much more expensive than embryonic stem cells. Not to mention that for now researchers are divided on the long-term impacts on altered DNA for reprogramming.
► What will the Japanese clinical trial consist of?
A team from the University of Kyoto announced on Monday (July 30th) that it will inject millions of iPS cells into the brains of seven patients aged 50 to 69 with Parkinson's disease. This neurodegenerative disease, due to the destruction of a certain type of neurons, causes slow movements, muscle stiffness and tremor. It affects more than ten million people worldwide.
In this clinical trial that begins Wednesday, August 1, the cells come not from patients but from healthy donors. The researchers hope that they will differentiate into neurons to compensate for the destruction caused by the disease. The observations will continue for two years.
Japan, at the forefront of the issue, has already conducted a first test of iPS cell transfer in patients with age-related macular degeneration (AMD), a disease of the retina and the leading cause of blindness in the elderly
Clinical trials with iPS cells in Japan