To receive a diagnosis of Alzheimer’s disease today, doctors use cognitive tests, which only detect changes in the brain once symptoms are already present.
Professor Ralph Martins, Neurobiologist at Macquarie University Department of Biomedical Sciences Research, told HelloCare elevated levels of certain proteins in the blood are also an indicator of Alzheimer’s disease and can be picked up on brain scans.
However, the scans cost up to $3,000 each and the health system simply doesn’t have the capacity to screen whole populations.
But now a Macquarie University study has shown older adults with no cognitive deficits but whose brain scans reveal elevated levels of the proteins associated with Alzheimer’s disease also have higher levels of Alzheimer’s-related proteins in their blood compared with adults with normal brain scans.
Due to improved technology, the Macquarie University study was able to identify minuscule levels of the proteins in the blood, a feat previously impossible because the volumes are so low.
Professor Martins said the new tool is 1,000 times more powerful than previous tools.
The study was funded by Anglicare, and 100 Anglicare retirement village residents took part.
All participants had no memory impairment. But scans revealed that one-third of the participants had high levels of amyloid in their brain, while two-thirds had “healthy” levels of the protein.
The highest level of accuracy (90%) was in the detection of green fluorescent protein (GFP), which makes it better than any other clinical method of diagnosing Alzheimer’s disease.
The study also looked at the participants after 12 months and found the levels of protein in the blood increased over time.
“So not only is it a diagnostic marker, we can also follow the progression of the disease,” Professor Martins said. “That’s what makes it even more exciting.”
Professor Martins believes the blood tests have the potential to provide a diagnosis of Alzheimer’s disease 15 to 20 years before symptoms appear.
There is currently only one drug treatment for Alzheimer’s disease, Aduhelm, which has been approved for use in the United States, but study results have been mixed. Some studies have shown the drug reduces the levels of protein in the brain, while others failed to show any benefit.
Nevertheless, the hope is that early intervention in the removal of amyloid proteins from the brain may prevent the disease from progressing.
The impact on the treatment of Alzheimer’s could be “huge”, he said.
Dr Pratishtha Chatterjee, lead author of the study and research fellow at Macquarie University Department of Biomedical Sciences Research, said, “These findings will allow more cost-effective screening and prognosis in clinical trials.”
Approximately 300,000 Australians currently have Alzheimer’s disease. There is no cure. The blood tests have the potential not only to provide early diagnosis and prevention of the onset of symptoms, they may also be used in the evaluation of drugs for treatment.