Biomarkers: The Key to Early Diagnosis of Alzheimer’s Disease

Recent Study from China Tracks Biomarkers over 20 Years in Individuals with or without Alzheimer's Disease, Revealing Significant Contrasts in Beta-Amyloid-42, Tau, and Other Biomarkers during the Study Period.

Early detection of Alzheimer’s may be possible through changes in pre-symptom biomarkers.

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Did you know that Alzheimer’s disease, the most common form of dementia, affects around 40 million people worldwide? Diagnosing this devastating disease can be difficult and often delayed due to the similar symptoms shared by various forms of dementia. However, researchers believe that biomarkers in cerebrospinal fluid (CSF) and blood plasma could hold the key to early diagnosis.

In a groundbreaking long-term study conducted in China, researchers discovered significant differences in several biomarkers between individuals who later developed Alzheimer’s disease and those who did not. These biomarkers provide valuable insights into the early stages of the disease, potentially allowing for earlier intervention and treatment.

Understanding Alzheimer’s Disease

Alzheimer’s disease is characterized by the buildup of beta-amyloid and tau proteins in the brain, leading to memory loss and confusion. While existing treatments can help manage the symptoms, they are most effective when administered early in the course of the disease. Therefore, early diagnosis is crucial to slowing the progress of Alzheimer’s.

The Power of Biomarkers

Biomarkers in CSF and blood plasma have emerged as promising indicators of Alzheimer’s disease. In the recently published study from China, researchers mapped biomarkers over a span of 20 years in individuals who later developed Alzheimer’s and those who did not. The findings revealed significant changes in the levels of beta-amyloid-42, tau, and other biomarkers over the course of the study.

According to Dr. Claire Sexton, senior director of scientific program and outreach at the Alzheimer’s Association, this study is a notable addition to the existing research. By including assessments made over 20 years, it unveiled changes up to 18 years before diagnosis, shedding light on the evolution of the disease and providing important representation of Asian populations.

Diving Deep into the Study

The study, part of the COAST study in China, enrolled participants aged 45-65 without any cognitive impairment, family history of Alzheimer’s, or life-threatening diseases. Follow-up tests including CSF and blood samples, neuropsychological tests, and imaging were conducted every 2-3 years until 2020.

At the final follow-up, researchers compared data from 648 participants who developed Alzheimer’s with the same number of participants who did not. The biomarkers were measured using enzyme-linked immunosorbent assay kits, and magnetic resonance imaging (MRI) scans were used to assess any changes in brain volume.

The key findings revealed that levels of beta-amyloid-42 started to decrease 18 years before diagnosis, while the ratio of beta-amyloid-42 to beta-amyloid-40 diverged 14 years before diagnosis. Changes in tau protein were observed 11 years before diagnosis, with phosphorylated tau 181 increasing in individuals with Alzheimer’s and total tau rising 10 years before diagnosis.

Furthermore, higher NfL levels, indicating neuroaxonal damage and axonal degeneration, were detected 9 years before diagnosis. Reduction in hippocampal volume, a region crucial for memory and learning, occurred 8 years before diagnosis.

Confirmation and Implications

While these changes in biomarkers may not come as a surprise to experts, they provide valuable insights into the underlying neuropathological events during the preclinical stages of Alzheimer’s disease. Dr. Emily Clark, associate director of Alzheimer’s Disease Care at the University of Rochester Medical Center, emphasizes that the sequential nature of these changes offers opportunities for early detection, intervention, and the development of targeted therapies.

However, it’s important to note that the study predominantly focused on a Han Chinese population, limiting the generalization of the findings to other populations. Further research, integration with other diagnostic measures, and consideration of genetic factors are necessary for precise interpretation and clinical implications.

The Future of Alzheimer’s Diagnosis and Treatment

With advancements in testing technology, a variety of tests, including blood tests, are being developed to inform the diagnosis of Alzheimer’s. These breakthroughs pave the way for early identification and treatment with disease-modifying therapies. For example, preclinical changes in beta-amyloid biomarkers hold potential significance for the utility of early treatment with amyloid lowering agents such as lecanemab and donanemab.

However, it’s essential to acknowledge that these treatments are still in the testing phase. Ongoing trials, like the AHEAD 3-45 trial using lecanemab and the TRAILBLAZER-ALZ 3 trial using donanemab, are exploring the impact of treating amyloid abnormalities without clinical symptoms of Alzheimer’s disease.

Addressing Your Concerns

Q: How reliable are biomarkers in diagnosing Alzheimer’s disease?

A: Biomarkers in CSF and blood plasma have shown promise in aiding the diagnosis of Alzheimer’s disease. While this new study contributes valuable insights, it’s important to consider the limitations, such as the specific population studied and potential selection bias. Incorporating multiple diagnostic measures and further research are necessary for accurate interpretation and clinical use of biomarkers.

Q: When should I consider getting tested for Alzheimer’s disease?

A: If you’re experiencing persistent memory loss, cognitive decline, or other concerning symptoms associated with Alzheimer’s disease, it’s crucial to consult a healthcare professional. They can guide you through the appropriate diagnostic process, which may include evaluating biomarkers, neuroimaging, and neuropsychological assessments.

Q: Can Alzheimer’s disease be prevented or cured?

A: Currently, there is no known cure for Alzheimer’s disease. However, adopting a healthy lifestyle that includes regular exercise, a balanced diet, mental stimulation, and social engagement may help reduce the risk factors associated with the disease. Ongoing research into early diagnosis, disease-modifying therapies, and preventive strategies provides hope for future advancements.

Q: Are there support groups or resources available for individuals and families affected by Alzheimer’s disease?

A: Yes! Various organizations, such as the Alzheimer’s Association, offer support groups, online resources, and educational materials for individuals and families impacted by Alzheimer’s disease. These resources can provide guidance, coping strategies, and a sense of community during challenging times.

Share and Stay Informed

The discovery of biomarkers that can potentially lead to early diagnosis and treatment of Alzheimer’s disease is groundbreaking. Stay informed about the latest advancements and share this article with others to raise awareness. Together, we can support ongoing research, improve diagnosis and treatment options, and ultimately make a difference in the lives of those affected by Alzheimer’s.


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