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

Published in the journal Brain, a recent study of the new blood test demonstrated that components in the human blood can modulate neurogenesis, which is the formation of new brain cells.

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

Alzheimer’s affects neurogenesis in the hippocampus during the early stages of the disease, however, previous studies have only evaluated neurogenesis in the disease’s later stages through autopsies.

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

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

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

The researchers made several key discoveries while studying how blood affected brain cells.

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

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

King’s IoPPN professor and the study’s 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.”

King’s College London researchers noted that these findings may help in further understanding the changes in the brain at the earliest stages of Alzheimer’s disease.

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