Brain donation is a rare and precious act that helps to advance medical research on neurodegenerative diseases, as is the case for Alzheimer’s disease.
Brain donation is vital to research. Since the 1980s, scientists have made major advances in the description of neurodegenerative diseases, in the identification of the molecules implicated or in the understanding of the mechanisms involved. On the occasion of Brain Week, which takes place from March 13 to 19 and is supported by the Vaincre Alzheimer Foundation, zoom in on the importance of this type of donation.
Unlike other organs, such as the kidneys, liver, heart or lungs, consent is not presumed for the brain. This organ cannot be transplanted to save the life of others, but is intended for research. The consent of the donor in writing, or of his trusted person, is therefore necessary for removal after death.
Better understand the disease to find new treatments
In France, the Neuro-CEB Biobank, a national tissue bank declared to the Ministry of Higher Education and Research, is responsible for collecting donations. “There are brain donations by disease (Parkinson, multiple sclerosis…), explains Maï Panchal, General and Scientific Director of the Vaincre Alzheimer Foundation. Concerning Alzheimer’s disease, there are about twenty consents per year and around 15 brain donations per year. Among the consents, there are many children of sick people. There is a greater need for healthy elderly people to donate brains”.
If brain donation is so important for research, it is because no experimental brain model, however precise, is similar to that of humans. Even today, the mechanisms of Alzheimer’s disease are poorly understood. Better identifying them could lead to the discovery of new molecules and the development of new treatments. “When researchers put forward a new hypothesis on the disease or find a molecule of interest, they must verify it on animal models and then confront the human reality”, specifies Maï Panchal. Thanks to the donation, researchers can thus compare sick and non-sick brains and validate or not their hypothesis on post-mortem human tissue.
“A brain is 10 years of research support!”
In the context of brain donation, the time between death and collection must not exceed 48 hours to avoid the degradation of molecules. A national network of neuropathologist experts from the Biobank makes it possible to meet this deadline throughout France. “Once the brain is collected, one hemisphere is fixed in the aldehyde format and the other hemisphere will be frozen at -80°C and sampled. Each sample represents the different regions of the brain (frontal, temporal, etc.), explains the General and Scientific Director. A brain is about 10 years of research.”
In practice, very small samples are used by researchers and a single brain can be used in many projects. The Biobank has thus been able to support more than 200 research projects since its creation and more than 100 articles have been published in scientific journals. “All the major advances, such as the discovery of the two toxic proteins that accumulate in the brains of Alzheimer’s patients, have been discovered thanks to brain donation,” emphasizes the specialist.
The path to multitherapy
In 2020, the Vaincre Alzheimer Foundation, for example, funded Dr. Dhenain’s project. Its objective: to identify the mechanisms responsible for the propagation and toxicity of amyloid deposits in the brain. His study showed that apparently healthy brain samples can transmit one of the lesions of Alzheimer’s disease. In exceptional circumstances, amyloid deposits could thus be transmitted from one patient to another after a medical procedure by injections of growth hormone from the brain, for example.
While it is possible to slow the progression of Alzheimer’s disease, there is no cure. “Immunotherapy approved by the American health authorities, and not yet approved in Europe, is not a miracle solution because even when implemented very early, the slowing down of cognitive decline is of the order of nearly 30%, underlines Mai Panchal. We realize that Alzheimer’s disease is multifactorial, that there are several proteins involved and several deleterious mechanisms. The solution would therefore be HAART.” A hypothesis that can be verified thanks to brain donation.
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