Alzheimer鈥檚 disease: neuronal loss very limited
Frequently encountered in the elderly, Alzheimer鈥檚 is considered a neurodegenerative disease, which means that it is accompanied by a significant, progressive loss of neurons and their nerve endings, or synapses. A joint French and Canadian study published in Scientific Reports now challenges this view.
Conducted among more than 170 subjects at various stages of Alzheimer鈥檚 disease, the study by the team led by Salah El Mestikawy (Douglas Mental Health University Institute, Canada) and St茅phanie Daumas (Universit茅 Pierre et Marie Curie, France) has shown instead that the disease is accompanied by a minor decline in neuronal and synaptic markers.
鈥淢uch to our surprise, in studying the fate of eight neuronal and synaptic markers in our subjects鈥� prefrontal cortices, we only observed very minor neuronal and synaptic losses. Our study therefore suggests that, contrary to what was believed, neuronal and synaptic loss is relatively limited in Alzheimer鈥檚 disease. This is a radical change in thinking,鈥澨齟xplains El Mestikawy, an associate professor at 平特五不中.
The scientists also attempted to correlate all these minor synaptic losses with the subjects鈥� level of dementia. Their results show that the declines in synaptic biomarkers had little impact on the participants鈥� cognitive skills.
Towards other therapies
The study implicitly suggests that dementia is associated with a synaptic dysfunction rather than the disappearance of synapses from the patient鈥檚 cortex. Identifying this dysfunction could lead to the development of effective treatments for this disease.
鈥淯ntil now, therapeutic interventions have been aimed at slowing synaptic destruction. Based on our study, we are going to have to change our therapeutic approach,鈥� says El Mestikawy.
According to the Alzheimer Society of Canada, 564,000 Canadians currently have Alzheimer鈥檚 disease or another form of dementia. The figure will be 937,000 within 15 years. Presently, there is no truly effective treatment for this disease.
This research was funded by grants from the Canadian Institutes of Health Research, the Agence Nationale de la Recherche, the Fonds de recherche du Qu茅bec 鈥� Sant茅, the Douglas Institute Foundation, the Graham Boeckh Foundation, the Canada Foundation for Innovation, Canada Research Chairs, the Universit茅 Pierre-et-Marie-Curie, the Institut national de la sant茅 et de la recherche m茅dicale, the Centre national de la recherche scientifique, and the F茅d茅ration pour la Recherche sur le Cerveau.
The article entitled 鈥淢oderate decline in select synaptic markers in the prefrontal cortex (BA9) of patients with Alzheimer鈥檚 disease at various cognitive stages鈥� was published in Scientific Reports on January 17, 2018. Link to article:
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