When it comes to brain pathology, Alzheimer's disease (AD) is defined by loss and gain: on the one hand, the progressive loss of neurons and on the other, the accumulation of amyloid plaques and tau tangles. In the past, accurate assessment of these pathological processes required brain imaging scans (MRI and PET) and biomarker measurements, usually performed on cerebrospinal fluid (CSF) samples obtained via lumbar puncture. In a new study published in Alzheimer's and Dementia, a team of researchers led by Prof. Alejo Nevado-Holgado (University of Oxford, UK) show that blood proteins can also predict the presence of AD pathology, accurately discriminating between people with mild cognitive impairment (MCI), MCI converters, and people with AD.
In 2018, the National Institute on Aging and the Alzheimer's Association (NIA-AA) proposed the ATN biomarker framework for classifying AD. In this framework, A refers to amyloid-beta, T refers to tau, and N refers to neurodegeneration, measured by using a range of different biomarkers. Blood-based biomarkers represent a promising, minimally-invasive advance on currently-available methods to measure ATN, which use brain imaging scans and/or CSF samples.
In their study, Prof. Nevado-Holgado and colleagues analysed samples and data from the EMIF-MBD cohort, comparing blood plasma profiles of 600 people with MCI or AD, with over 370 of their unaffected peers. Using the SOMAscan technology, which can measure over 4,000 different blood proteins in a single plasma sample, the researchers identified groups of proteins that changed in correlation with traditional ATN markers. Cross-referencing these results with clinical measures including AD diagnosis, MCI conversion and memory test scores, they found specific groups of proteins that could classify EMIF-MBD participants based on their AD diagnosis or conversion. These proteins also point to potential targets for further studies aiming to understand the molecular basis of AD.
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.12322
