In a study from Hokkaido University and Toppan, scientists have developed a method to detect build-up of amyloid β in the brain, a characteristic of Alzheimer’s disease, from biomarkers in blood samples.
Alzheimer’s disease is a neurodegenerative disease, characterized by a gradual loss of neurons and synapses in the brain.
One of the primary causes of Alzheimer’s disease is the accumulation of amyloid β (Aβ) in the brain, where it forms plaques.
Alzheimer’s disease is mostly seen in individuals over 65 years of age, and cannot currently be stopped or reversed. Thus, Alzheimer’s disease is a major concern for nations with aging populations, such as Japan.
In the study, the team developed a biosensing technology that can detect Aβ-binding exosomes in the blood of mice, which increase as Aβ accumulates in the brain.
When tested on mice models, the Aβ-binding exosome Digital ICA (idICA) showed that the concentration of Aβ-binding exosomes increased with the increase in age of the mice.
This is strong as the mice used were Alzheimer’s disease model mice, where Aβ builds up in the brain with age.
In addition to the lack of effective treatments for Alzheimer’s, there are few methods to diagnose Alzheimer’s.
Alzheimer’s can only be definitively diagnosed by direct examination of the brain—which can only be done after death.
Aβ accumulation in the brain can be measured by cerebrospinal fluid testing or by positron emission tomography; however, the former is an extremely invasive test that cannot be repeated, and the latter is quite expensive.
Thus, there is a need for a diagnostic test that is economical, accurate and widely available.
Previous work by the team had shown that Aβ build-up in the brain is associated with Aβ-binding exosomes secreted from neurons.
Exosomes are membrane-enclosed sacs secreted by cells that possess cell markers on their surface. The team found a way to quantify the concentration of Aβ-binding exosomes in as little as 100 µL of blood.
The device they developed traps molecules and particles in a sample one-by-one in a million micrometer-sized microscopic wells on a measurement chip and detects the presence or absence of fluorescent signals emitted by the cleaving of the Aβ-binding exosomes.
Clinical trials of the technology are currently underway in humans.
The team says this highly sensitive idICA technology is the first application of ICA that enables highly sensitive detection of exosomes that retain specific surface molecules from a small amount of blood without the need to learn special techniques.
For more information about brain health, please see recent studies about why women are more susceptible to Alzheimer’s, and results showing scientists find alternative drug strategy against Alzheimer’s disease.
The study was conducted by Kohei Yuyama et al and published in the journal Alzheimer’s Research & Therapy.
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