Experimental transmission of Alzheimer’s disease lesions

Alzheimer’s disease is a major mental illness that affects about one million people in France. It is associated with the presence of two major lesions, the deposition of beta-amyloid proteins and the accumulation in neurons of abnormal tau proteins. The accumulation of aberrant tau proteins is closely related to the cognitive impairment that characterizes the disease. Des études basées sur des observations post-mortem de cerveaux humains ont établi que l’administration accidentelle lors d’actes médico-chirurgicaux de composés contaminés par de l’amyloïde-β peut induire une ïté caséde cri βé 80 the scientist). One difficulty in studying the transmission of amyloid beta/tau lesions in humans is the long delay (several decades) between the potentially inducible medical-surgical action and the onset of pathology.

Scientists explain that in addition to amyloid-beta diseases, tau diseases can be transmitted by inoculating samples from a patient’s brain to another healthy brain (here from humans to non-human primates (mouse moths) including a brain environment close to that of the brain). Humans). Transmitted lesions spread to colonize the entire brain. This transmission is associated with the emergence of memory problems.

30 years ago, several studies indicated that mutations in various proteins could induce Alzheimer’s disease lesions in animal models. This new study highlights a second biological mechanism, not genetics, capable of inducing all of the lesions of Alzheimer’s disease and causing them to spread in the brain. This underscores the need to organize a systematic follow-up of individuals who have experienced medical-surgical procedures associated with the risk of transmission of amyloid beta and tau proteins.

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© Mark Dennin

Intracerebral inoculation of extracts from the brains of Alzheimer’s patients into mouse lemurs induces microscopic lesions typical of Alzheimer’s disease (amyloidosis and allopathic) and spread of these lesions from the focal point of inoculation to the whole brain. These changes are associated with the emergence of cognitive disorders. These data suggest that the non-genetic biological mechanisms associated with this transmission have an important role in the biology of Alzheimer’s disease.

To find out more:
Transmission of amyloid beta and tau diseases is associated with cognitive impairment in primates.
Lam, S, Betty, F, Herrard, A-S, Boluda, S, Edarkawi, S, Gillermere, M, Brain Bank Neurological CP Network, Bowie, L, Doekerts, C. , Haik, S., Picq, J.-L. , Dhenain, M.
Acta Neuropathologica Communications
October 12 2021
https://doi.org/10.1186/s40478-021-01266-8.

Iatrogenic transmission of beta-amyloid and tau proteins: clinical and biomedical significance for Alzheimer’s disease.
Dhenain M.
Bulletin of the National Academy of Medicine
August 2021
https://doi.org/10.1016/j.banm.2021.04.018.

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