A new test can detect Alzheimer’s disease three and a half years before it is diagnosed, a new study suggests.
New research from the Institute of Psychiatry, Psychology and Neuroscience (IoPPN) at King’s College London has established a blood-based test that can predict the risk of the condition.
The study supports the idea that components in human blood can affect the formation of new brain cells, a process called neurogenesis.
This process takes place in a part of the brain called the hippocampus, which is involved in learning and memory.
While Alzheimer’s affects the formation of new brain cells in the hippocampus in the early stages of the disease, neurogenesis in the last stages of previous research could only be studied through autopsy.
To understand the early changes, the researchers took blood samples from 56 people with mild cognitive impairment (MCI), a condition in which someone begins to experience a deterioration in their memory or cognitive ability, over several years.
Although not everyone with MCI will develop Alzheimer’s disease, those with the condition progress to a diagnosis at a much higher rate than the wider population.
Thirty-six of the 56 people in the study were diagnosed with Alzheimer’s.
When the researchers used only the blood samples taken furthest from the diagnosis of Alzheimer’s disease, they found that the changes in neurogenesis occurred 3.5 years before a clinical diagnosis.
Professor Sandrine Thuret, lead author of the King IoPPN study, said: “Previous studies have shown that blood from young mice can have a rejuvenating effect on cognition in older mice by improving neurogenesis of the hippocampal.
“This gave us the idea to model the process of neurogenesis in a dish containing human brain cells and human blood.
“In our study, we wanted to use this model to understand the process of neurogenesis and use changes in this process to predict Alzheimer’s disease, and we found the first evidence in humans that the the body’s circulatory system can have an impact on the brain’s ability to form. new.” cells.”
According to the study, blood samples from people who later developed Alzheimer’s disease promoted a decrease in cell growth and cell division.
They also promoted an increase in apoptotic cell death – the process by which cells are programmed to die, the study found.
While the reasons for the increased neurogenesis are still unclear, researchers suspect that it may be an early compensatory mechanism for the loss of brain cells that occurs in people with Alzheimer’s disease.
Dr Edina Silajdzic, joint first author of the study, added: “Our results are extremely important as they may allow us to non-invasively predict the onset of Alzheimer’s disease early.
“This can complement other blood-based biomarkers that reflect the classic signs of the disease, such as the accumulation of amyloid and tau (the “flagship” proteins of Alzheimer’s disease).”
The researchers say the findings, published in the journal Brain, may provide an opportunity to better understand the changes the brain undergoes in the earliest stages of Alzheimer’s.
