PARIS, August 24 (Benin News) –
Researchers from the University of Illinois at Chicago, USA, have found that increasing the production of new neurons in mice with Alzheimer’s disease (AD) solves the animals’ memory problems .
The study, published in the Journal of Experimental Medicine (JEM), shows that new neurons can be incorporated into neural circuits that store memories and restore their normal function, suggesting that stimulating neuron production could be a strategy viable for treating patients with Alzheimer’s disease.
New neurons are produced from neural stem cells by a process known as neurogenesis.
Previous studies have shown that neurogenesis is impaired both in patients with Alzheimer’s disease and in laboratory mice carrying genetic mutations linked to the disease, particularly in a region of the brain called the hippocampus, which is crucial for memory acquisition and retrieval.
“However, the role that newly formed neurons play in memory formation is unclear, and it is unclear whether defects in neurogenesis contribute to the cognitive impairments associated with Alzheimer’s disease,” says Professor Orly. Lazarov of the Department of Anatomy and Cell Biology at the University of Illinois College of Medicine in Chicago.
In the new study, Lazarov and his colleagues stimulated neurogenesis in mice with Alzheimer’s disease by genetically enhancing the survival of neural stem cells. They deleted Bax, a gene that plays an important role in neural stem cell death, which ultimately led to more new neurons maturing. Increasing the production of new neurons in this way restored the animals’ performance in two different tests measuring spatial recognition and contextual memory.
By fluorescently labeling neurons activated during memory acquisition and retrieval, the researchers determined that in the brains of healthy mice, neural circuits involved in memory storage include many newly formed neurons, as well as older and more mature neurons. These memory storage circuits contain fewer new neurons in mice with Alzheimer’s disease, but the integration of newly formed neurons was restored when neurogenesis was increased.
Further analysis of the neurons that form memory storage circuits revealed that increased neurogenesis also increases the number of dendritic spines, which are structures at synapses known to be essential for memory formation. and restores a normal pattern of neuronal gene expression.
Lazarov and his colleagues confirm the importance of newly formed neurons for memory formation by specifically inactivating them in the brains of mice with Alzheimer’s disease. This negated the beneficial effects of enhancing neurogenesis, preventing any improvement in the animals’ memory.
“Our study is the first to show that impairments in hippocampal neurogenesis play a role in memory deficits associated with Alzheimer’s disease by decreasing the availability of immature neurons for memory formation,” says Dr. Lazarov. Taken together, our results suggest that increased neurogenesis may have therapeutic value in patients with AD.