New Study Reveals Early Biomarkers of Alzheimer’s Disease
Alzheimer’s disease, a devastating condition that silently destroys the brain long before symptoms appear, may have new clues for early detection and intervention. A groundbreaking study conducted in China has shed light on the sequence of changes that occur in the brain before the onset of Alzheimer’s, offering a potential window for future treatments.
Over a span of 20 years, researchers closely monitored middle-aged and older adults using brain scans, spinal taps, and other tests. The study found that individuals who eventually developed Alzheimer’s had higher levels of an Alzheimer’s-linked protein in their spinal fluid 18 years prior to diagnosis. Additionally, the study detected another biomarker of the disease every few years thereafter.
While the exact formation of Alzheimer’s is still unknown, one of its early hallmarks is the accumulation of a sticky protein called beta-amyloid, which forms brain-clogging plaques over time. However, amyloid alone is not sufficient to cause memory loss, as many healthy individuals also have a significant amount of plaque in their brains. The presence of an abnormal tau protein, which forms neuron-killing tangles, is believed to be one of several contributing factors.
The findings of this research, published in the New England Journal of Medicine, provide a timeline for the progression of these abnormalities. Dr. Richard Mayeux, an Alzheimer’s specialist at Columbia University, emphasized the significance of this study, stating that “knowledge of the timing of these physiological events is critical” for testing new treatments and potentially preventing Alzheimer’s in the future.
Alzheimer’s affects more than 6 million Americans and millions more worldwide, making it the most common form of dementia. Unfortunately, there is currently no cure for the disease. However, last year saw a breakthrough with the approval of a drug called Leqembi, which demonstrated clear evidence of slowing the progression of early Alzheimer’s, albeit for a limited duration. Leqembi works by clearing away amyloid protein from the brain. Researchers are also exploring the possibility of delaying Alzheimer’s onset by treating high-risk individuals before symptoms appear. Additionally, drugs targeting tau are being developed.
Tracking these silent brain changes is crucial for advancing research in Alzheimer’s treatment. In rare cases of inherited Alzheimer’s that affect younger individuals, a toxic form of amyloid begins accumulating approximately two decades before symptoms manifest, followed by the onset of tau at a later stage. The new study reveals the order in which these biomarker changes occur in more common cases of old-age Alzheimer’s.
The researchers from Beijing’s Innovation Center for Neurological Disorders compared 648 individuals eventually diagnosed with Alzheimer’s to an equal number of healthy individuals. The study found that the amyloid biomarker was the first to appear, 18 years or 14 years prior to diagnosis, depending on the test used. Differences in tau were detected next, followed by markers indicating trouble in neuronal communication. Several years later, differences in brain shrinkage and cognitive test scores between the two groups became apparent.
Claire Sexton, the Alzheimer’s Association’s senior director of scientific programs, highlighted the importance of understanding viable treatment targets and when to address them. She expressed optimism about the future development of new therapies and preventions with this knowledge. Sexton also mentioned that blood tests are on the horizon, which will make it easier to track amyloid and tau levels.
The findings of this study provide hope for early detection and intervention in Alzheimer’s disease. By understanding the sequence of biomarker changes and their timing, researchers can accelerate the development of effective treatments and preventive measures. While there are currently no practical implications from this research, it serves as a significant step forward in the fight against Alzheimer’s, offering a glimmer of hope for millions affected by this devastating disease.
Disclaimer: This article is based on information from a study conducted in China and published in the New England Journal of Medicine. The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The content of this article is the responsibility of the AP.
