In 2017, it was estimated that over 5.5 million people in the United States were affected by Alzheimer’s disease, which ranks as the sixth-leading cause of death in the country. A new study observing the effects of a group of peptides called amyloid-β, closely linked to Alzheimer’s, suggests the potential of using a blood test to recognize high risks of developing the condition before noticeable symptoms appear—possibly up to 30 years before the condition develops.
Alzheimer’s disease is a type of dementia, a category of diseases that are associated with memory loss and the deterioration of cognitive and motor skills. Its causes are unknown, but old age, lifestyle choices, and genetic predisposition are believed to be some factors that affect its onset. Before the aforementioned study was conducted, few ways of testing for Alzheimer’s before its onset were known. However, the monitoring of peptides, or small collections of amino acids that differ from proteins in size, may prove to be a breakthrough that aids medical professionals in detecting, and eventually finding a cure for, one of the world’s most costly and devastating diseases.
Early detection of Alzheimer’s is crucial for effective treatment, as the progression of the disease is irreversible. In healthy individuals, the amyloid-β peptide is digested and eliminated. However, in diseased brains, the amyloid-β can collect to form insoluble plaques on the brain 30 years before other symptoms appear. These plaques cause masses of neurons to be affected by the peptides, causing shrinkage of brain tissue, and over time, the gradual loss of vital functions of the brain. The currently-used method of detecting the protein fragments uses brain scans, which are notoriously expensive and impractical. Blood tests would provide a much more accessible way for individuals to assess their chances of developing the disease.
The recent investigation involved the collaboration of researchers from universities in Japan and Australia, who observed evidence of amyloid flowing through the bloodstream by collecting blood samples from 373 individuals and using mass spectrometry to search for amino acids and peptides linked to the activity of the toxic peptide. Through analysis of the results, the test was able to accurately predict plaque buildup in 90 percent of the observed cases. “From a tiny blood sample, our method can measure several amyloid-related proteins, even though their concentration is extremely low,” reported Koichi Tanaka, a researcher from the Shimadzu Corporation in Japan.
Although the study is still in its early stages and no new Alzheimer’s treatment has yet been developed, the information collected could lead to more efficient and directed clinical trials in the future. “These data are very promising and may be incredibly useful in the future, in particular for choosing which people are suited for clinical trials and for measuring whether amyloid levels are changed by treatments in trials,” commented Professor Tara Spires-Jones from the Centre for Discovery Brain Sciences at the University of Edinburgh. The study was also the first to discover and demonstrate a strong association of blood plasma amyloid with brain and cerebrospinal fluid, another breakthrough that could also lead to potential treatment options in the future.