Researchers at King’s College London, Institute of Psychiatry, Psychology & Neuroscience (IoPPN) have developed a blood-based test that could predict the risk of Alzheimer’s disease up to 3.5 years before clinical diagnosis.

A recently published study of their blood test showed that components in the human blood can modulate neurogenesis (formation of new brain cells).

Neurogenesis occurs in an important part of the brain, called the hippocampus, associated with learning and memory.

Alzheimer’s affects the neurogenesis in the hippocampus, in the early stages of the disease, but previous studies evaluated neurogenesis only in the later stages.

To understand the early changes, IoPPN researchers collected blood samples from 56 individuals with Mild Cognitive Impairment (MCI), over several years.

MCI is a condition where people start experiencing a worsening of their memory or cognitive ability.

Among the 56 study participants, 36 received a diagnosis of Alzheimer’s disease.

King’s IoPPN professor, the study lead author, Sandrine Thuret said: “Previous studies have shown that blood from young mice can have a rejuvenating effect on the cognition of older mice by improving hippocampal neurogenesis.

“This gave us the idea of modelling the process of neurogenesis in a dish using human brain cells and human blood.

“In our study, we aimed to use this model to understand the process of neurogenesis and to use changes in this process to predict Alzheimer’s disease and found the first evidence in humans that the body’s circulatory system can have an effect on the brain’s ability to form new cells.”

The researchers made several key discoveries during their study on how blood affected brain cells.

The blood samples collected from participants, who subsequently developed Alzheimer’s disease, promoted a decrease in cell growth and an increase in apoptotic cell death.

In addition, the researchers found that the samples also enhanced the conversion of immature brain cells to hippocampal neurons.

The researchers said that the findings could help further understand the changes experienced by the brain at the earliest stages of Alzheimer’s disease.

Furthermore, John and Lucille van Geest Foundation, the Medical Research Council UK, the Cohen Charitable Trust, the Galen and Hilary Weston Foundation and the Rhodes Trust supported the study by providing funding.