Most people receive a diagnosis of Alzheimer’s only after they exhibit symptoms of the disease. At this stage, treatment options seeks to slow down the progression of the disease. Yet research has shown the disease may start well before the symptoms begin to show, when amyloid beta proteins start to clump together forming oligomers potentially triggering the onset of Alzheimer’s.
Researchers can now detect ‘toxic’ oligomers in individuals who showed no signs of cognitive impairment at the time the blood sample was taken, but who developed Alzheimer’s at a later date.
A team led by researchers at the University of Washington has developed the test that can measure levels of amyloid beta oligomers in the blood samples. Their test – known by the acronym SOBA – could detect oligomers in the blood of patients with Alzheimer’s disease, but not in most members of a control group who showed no signs of cognitive impairment at the time the blood samples were taken.
However, SOBA did detect oligomers in the blood of 11 individuals from the control group. Follow-up examination records were available for 10 of these individuals, and all were diagnosed years after with mild cognitive impairment or brain pathology consistent with Alzheimer’s disease. Essentially, for these 10 individuals, SOBA had detected the toxic oligomers before symptoms surfaced.
“What clinicians and researchers have wanted is a reliable diagnostic test for Alzheimer’s – and not just an assay that confirms a diagnosis of Alzheimer’s, but one that can also detect signs of the disease before cognitive impairment happens,” said senior author Professor Valerie Daggett.
“That’s important for individuals’ health and for all the research into how toxic oligomers of amyloid beta go on and cause the damage they do. What we show here is that SOBA may be the basis of such a test. We are finding that many human diseases are associated with the accumulation of toxic oligomers that form these alpha sheet structures. “