Sign up for our eNews and discover more about what we're up to, the difference we're making, and, most importantly, how you can help.
Australian research teams from Neuroscience Research Australia (NeuRA), the Florey Institute and Edith Cowan University, have collaborated with a global network of researchers on a study that has revealed evidence for a blood test that can predict familial Alzheimer’s disease 16 years before clinical symptoms appear.
The details of the study, which has been run by the Dominantly Inherited Alzheimer Network (DIAN) since 2008, were published last month in Nature Medicine, which you can find by clicking here.
NeuRA CEO Professor Peter Schofield said the DIAN study has allowed the researchers from the USA, England and Germany, as well as the three Australian teams, to track families with the rare inherited Alzheimer’s disease gene, and the research has provided critical insights into the biomarkers for the disease.
“Being able to identify a particular signature in the blood is the first step in the early detection and treatment of this devastating disorder of the brain,” Professor Schofield said.
“We hope that a test could become part of a routine medical check-up in the future, providing a cost-effective and efficient early warning system for the disease,” he said.
The research centred around the protein NfL, which is a crucial building block of brain cells. This building block is released into the bloodstream when these cells start to die, whether due to Alzheimer’s disease, traumatic brain injury or other neurodegenerative diseases.
This study therefore looked at levels of NfL in predicting neurodegeneration and clinical progression in pre-symptomatic Alzheimer’s disease, working on the assumption that increased levels of NfL in the blood may be linked to greater levels of damage to the brain. In turn, being able to detect such damage could be useful in identifying Alzheimer’s disease many years before symptoms develop.
The Florey Institute’s Professor Colin Masters AO said an NfL blood test was shown to accurately predict when members of a family with inherited Alzheimer’s disease would begin to show symptoms.
“NfL levels rise whenever the brain is damaged, and as Alzheimer’s disease affects 30 per cent of people over the age of 80, we hope that NfL will become part of a GP’s standard battery, like annual cholesterol testing,” Professor Masters said.
“We would send patients off for more specific Alzheimer’s disease tests if the results came back showing a cause for concern,” he said.
During the study, researchers looked at the NfL levels of 243 people carrying a gene predisposing them to Alzheimer’s disease, as well as 162 family members without the gene. The results showed the rate of increase in levels of NfL was higher for people genetically predisposed to Alzheimer’s disease than those without the gene of interest, with these differences becoming apparent 16 years before symptoms were expected to be seen.
Accurately detecting the early stages of the disease enables treatment and appropriate strategies to be initiated sooner.
What’s more, the period during which NfL showed the fastest build-up proved to be a key period when patients converted from pre-symptomatic disease into cognitive and memory decline.
Further work suggests both higher levels and a steeper increase of NfL in the blood might be linked to faster levels of thinning of a region of the brain’s cortex known to be affected by Alzheimer’s disease, as well as faster decline in memory and cognition.
The study’s findings could therefore be used by doctors in the future not only to detect Alzheimer’s disease early, but also to help anticipate when patients might start to show symptoms.
However, because the study focused on families with a predisposition to Alzheimer’s disease, it must be noted that the many other conditions that can also cause increased levels of NfL mean it is not clear how useful the measure would be among individuals living with multiple health problems.
“Next steps for the test include replicating the results in sporadic Alzheimer’s disease patients, who are older and often have other health issues,” Professor Schofield said.