A unique brain protein measured in the blood could be used to diagnose Alzheimer’s disease decades before symptoms develop, according to new Edith Cowan University (ECU) research.

Published in Nature journal Translational Psychiatry, the study is the first to find that people with elevated glial fibrillary acidic protein (GFAP) in the blood also have increased amyloid beta in the brain, a known indicator of Alzheimer’s disease.

GFAP is a protein normally found in the brain, but it is released into the blood when the brain is damaged by early Alzheimer’s disease.

The study’s lead researcher, ECU Professor Ralph Martins AO, told HealthTimes that the discovery offered a promising new avenue for early diagnosis.

“Blood biomarkers are becoming an exciting alternative to the existing expensive and invasive methods of diagnosing Alzheimer’s disease,” said Professor Martins.

“Current drug treatments for Alzheimer’s disease are made to treat people with symptoms. So far, these drugs are failing miserably.”

“The focus is now on people who don't have symptoms, but have the pathology in their brain. What that means is the brain is less ravaged, even though pathology is building up, and that’s why early detection is so important.”

“Early diagnosis is critical to allow us to implement medication and lifestyle interventions that can help delay the progression of the disease and give people more time before symptoms develop.”

Professor Martins said that the last couple of years have seen big breakthroughs in the field of biomarkers closely reflecting changes in the brain, which were once seen as a “pie in the sky”. 

This particular study involved 100 Australians aged between 65 and 90 years of age with no symptoms of Alzheimer’s disease.

“We’ve clearly shown GFAP is a very sensitive and strong predictor for changes in the brain.”

“Its strength is that it can pick up changes in people that don't yet have symptoms, and we believe it’s probably more powerful than other biomarkers from that perspective.”

Alzheimer’s disease affects more than 340,000 Australians and more than 35 million people in the world. Current diagnosis involves a brain scan or spinal fluid tests.

“The problem is that the gold standard [for diagnosis] today is to test for amyloid, which is quite expensive – around $3,000 – or to do a lumbar puncture, which hasn’t been very attractive in Australia”, Professor Martins said.

“Blood biomarkers are the most obvious way for early diagnosis – provided you get that level of robustness in the method, and it is now reaching that level.”

“It’s an attractive option, because people have blood tests all the time, so the test would be much cheaper, and only cost around $50-60.”

While the development of a blood test for Alzheimer’s disease would be revolutionary, Professor Martins said that other important steps needed to happen before the findings of the GFAP study could be incorporated into clinical practice.

“We’ve got to be careful. We can’t jump the gun just yet, but we're very close.”

“For us, the next steps are firstly to compare, head-to-head, whether this is a better method than others, or would it add value to combine it with other methods – those are questions we're addressing in the current paper”, Professor Martins explained.

“Then we need to test it in a much larger study, and we have a study in Australia that’s been running for 15 years, called the AIBL Study. It is world recognised, and we’re currently now investigating its validation in this cohort.”

“We’d like to then see other groups replicate these findings. We’d also look to working with a biotech company to take it to the next level”, he said.