A Tau Based Biomarker of Alzheimer's Progression and Cognitive Decline
Research groups have been hard at work over the past decade to build better biomarkers for Alzheimer's disease. Several blood-based biomarkers are quite advanced in their development. Here, researchers propose a less convenient cerebrospinal fluid biomarker, but still an improvement over the cost of brain imaging technologies when it comes to tracking the progression of the condition. Better, cheaper assays for Alzheimer's disease are certainly needed, particularly when it comes to the early stages of the condition, in which symptoms are mild or non-existent. Prevention is always easier than coping with a condition in its later stages.
By studying 667 people at various stages of Alzheimer's disease, the researchers discovered in the cerebrospinal fluid that levels of a specific form of tau - known as microtubule binding region (MTBR)-tau243 - track with the amount of damaging tau tangles in the brain and with the degree of cognitive decline. The average age of participants was 71, and the group included healthy people as well as people at all stages of disease, ranging from those with some amyloid in their brains but no cognitive symptoms, to those with extensive amyloid and tau in their brains and a diagnosis of dementia. The researchers compared cognitive function with levels of various forms of tau in the cerebrospinal fluid and with levels of amyloid and tau in the brain, as measured by amyloid and tau PET scans.
The researchers analyzed data from people who volunteered for Alzheimer's research studies through the Biomarkers For Identifying Neurodegenerative Disorders Early and Reliably (BioFINDER)-2 program. Levels of MTBR-tau243 in the cerebrospinal fluid correlated strongly with brain tau tangle levels and cognitive function. As MTBR-tau243 levels went up, tau levels in the brain also went up, and scores on cognitive tests went down. In contrast, levels of another form of tau in the cerebrospinal fluid, phosphorylated tau, tracked mainly with brain amyloid levels but not with brain tau levels or cognitive function. By combining the two forms of tau in the cerebrospinal fluid - phosphorylated tau and MTBR-tau243 - the researchers were able to predict cognitive function almost as well as by using tau-PET imaging.
Link: https://medicine.wustl.edu/news/tau-based-biomarker-tracks-alzheimers-progression/