New biomarker can spot Alzheimer's years before onset

Scientists have identified a novel potential biomarker, present in cerebral spinal fluid (CSF), that can help detect Alzheimer's disease at least a decade before symptoms appear.
This may be the earliest known biomarker associated with the risk of developing Alzheimer's disease.
"If our initial findings can be replicated by other laboratories, the results will change the way we currently think about the causes of Alzheimer's disease," said Dr Ramon Trullas, research professor at the Spanish National Research Council (CSIC) Institute of Biomedical Research of Barcelona and lead author of the study.
"This discovery may enable us to search for more effective treatments that can be administered during the preclinical stage," Trullas said.

The relationship of currently known biomarkers with the cause of the disease is unclear, making it nearly impossible to diagnose preclinical stages of the disease with any real certainty.
The CSIC researchers demonstrated that a decrease in the content of mitochondrial DNA (mtDNA) in CSF may be a preclinical indicator for Alzheimer's disease; furthermore, there may be a directly causative relationship.

The hypothesis is that decreased mtDNA levels in CSF reflect the diminished ability of mitochondria to power the brain's neurons, triggering their death.
The decrease in the concentration of mtDNA precedes the appearance of well-known biochemical Alzheimer's biomarkers (the A beta 1-42, t-tau, and p-tau proteins), suggesting that the pathophysiological process of Alzheimer's disease starts earlier than previously thought and that mtDNA depletion may be one of the earliest predictors for the disease.

Trullas hopes that other laboratories and hospitals will successfully replicate his group's research results, confirming that reduced mtDNA levels should be investigated as a possible cause of Alzheimer's disease.
By finding a way to block this degeneration, clinicians may be able to diagnose and treat Alzheimer's disease before symptoms appear.
The study was published in journal Annals of Neurology.