An American study examined the effects of an immunosuppressant on mice affected by Alzheimer’s disease and epileptic seizures.
- Alzheimer’s disease is a neurodegenerative pathology, which impairs various cognitive functions (memory, learning, language, etc.).
- American researchers have found that people with Alzheimer’s disease who have had epileptic seizures show a more rapid cognitive decline than other patients affected by this condition.
- An immunosuppressant could be a treatment option to preserve cognitive functions in patients suffering from Alzheimer’s disease.
Alzheimer’s disease results in a slow degeneration of neurons. Initially, this pathology mainly affects memory before gradually extending to other cognitive functions of the brain such as language, reasoning or learning.
Faster cognitive decline in patients with epilepsy and Alzheimer’s disease
In a recent study published in the journal Brain, American researchers observed the post-mortem tissues of patients suffering from Alzheimer’s disease and having experienced at least one epileptic attack. They then found that two neurotransmitters, glutamate and GABA, which work together to manage messages between neurons, were dysregulated. The neurons of these people showed increased excitability and suppressed inhibition. This means that the brain sends more signals between neurons than it needs. The study authors called this state “overactive brain.”
According to scientists, this alteration of neurons could explain why people with Alzheimer’s disease who have had epileptic seizures show faster cognitive decline than those who do not suffer from epileptic seizures. “Now that we have identified the mechanisms that cause neurons to overexcite and lead to seizures that accelerate Alzheimer’s disease, we can explore therapies that can reverse the imbalance and slow the progression of this pathology.”explained Frances E. Jensen, lead author of the study and chair of the department of neurology at the Perelman School of Medicine at the University of Pennsylvania (United States).
Alzheimer’s disease: the effects of an immunosuppressant to preserve cognitive functions
The American team then analyzed the effects of rapamycin, an immunosuppressant mainly indicated after organ transplantation, on mice affected by Alzheimer’s disease and epileptic seizures. They noticed that this treatment helped regulate overexcited neurons and preserve cognitive functions such as memory and learning.
As part of this study, the brain activity of the rodents was also monitored, in order to determine at what stage of Alzheimer’s disease this neuronal dysfunction occurs. Even before the appearance of cognitive symptoms, an increase in excitability and a decrease in inhibition of neurons occurred in the early stages of the pathology in the subjects. “When Alzheimer’s disease is diagnosed, for a good number of people, when they begin to receive treatments, the disease is already advanced and they have lost a large part of their cognitive functions (…) Our research is a step exciting towards the possibility of intervening with treatment before the appearance of symptoms, in order to slow the devastating effects of the condition”noted Aaron Barbour, co-author of the work and postdoctoral researcher in the department of neurology at the Perelman School of Medicine.
