The blood test, currently only available for research-related purposes, measures a specific peptide to inform scientists with 90 per cent accuracy if a patient has the very earliest stages of Alzheimer’s disease.
Professor Colin Masters of the Florey Institute of Neuroscience and Mental Health, and The University of Melbourne, who co-led the research published in Nature, said: “This new test has the potential to eventually disrupt the expensive and invasive scanning and spinal fluid technologies.
“In the first instance, however, it will be an invaluable tool in increasing the speed of screening potential patients for new drug trials,” Professor Masters said.
“Progress in developing new therapeutic strategies for Alzheimer’s disease has been disappointingly slow. None of the three drugs currently on the market treat the underlying disease. New drugs are urgently required, and the only way to do that is to speed up the whole process,” he said.
“That requires trials with rigorous and economical patient selection, to avoid recruiting patients who may not even have Alzheimer’s disease. Due to the long timespans involved, pharmaceutical companies require accurate predictions of who is most at risk.”
One of the essential hallmarks of Alzheimer’s disease is the buildup of an abnormal peptide in the brain, called beta-amyloid. The process starts silently about 30 years before any outward signs of dementia.
Current tests for beta-amyloid are expensive, invasive and include brain scans with radioactive tracers, or analysing spinal fluid taken via a lumbar puncture. Diagnosis is usually made without these tools, rather by assessing a patient’s range of symptoms.
The new test was the result of an extensive international collaboration. The key technology, known as IP-MS, was developed by Shimadzu Corporation in Japan. The University of Tokyo, Kyoto University, Kindai University, and Tokyo Metropolitan Institute of Gerontology were all key collaborators on the research.
Blood samples from patients in a large study from the Japanese National Center for Geriatrics and Gerontology (NCGG) were analysed to identify the relevant peptides.
The peptide combinations indicating brain beta-amyloid burden were then tested against patient samples from the Australian Imaging, Biomarker and Lifestyle Study of Aging (AIBL), a partnership between the Florey Institute, The University of Melbourne, CSIRO, Edith Cowan University, and Austin Health.
The leader of the Japanese team, Director-general of Research Institute at NCGG Professor Katsuhiko Yanagisawa, said: “Our study demonstrates the high accuracy, reliability and reproducibility of this blood test, as it was successfully validated in two independent large datasets from Japan and Australia.”
Dr Koichi Tanaka at Shimadzu Corporation was instrumental in developing the initial blood testing procedure. Dr Tanaka won the Nobel prize in Chemistry in 2002 for the technique.
“From a tiny blood sample, our method can measure several amyloid-related proteins, even though their concentration is extremely low,” Dr Tanaka said.
“We found that the ratio of these proteins was an accurate surrogate for brain amyloid burden.”
The University of Melbourne