Innovative Blood Test Offers New Hope for Early Alzheimer's Detection

Overview

Researchers at the Keck School of Medicine of USC have introduced a groundbreaking blood test designed to detect early indicators of Alzheimer's disease by measuring specific proteins associated with the condition. This innovative test, named the Penta-Plex Alzheimer's Disease Capture Sandwich Immunoassay (5ADCSI), has the capability to identify five biomarkers simultaneously, surpassing the capabilities of existing blood tests while utilizing widely available laboratory equipment.

The findings of this proof-of-concept study have been published in the Journal of Alzheimer's Disease.

Alzheimer's disease is characterized by the accumulation of proteins, including amyloid and tau, in both the brain and bloodstream as the disease progresses. Early detection via blood tests can facilitate timely interventions, potentially delaying cognitive decline.

Current Alzheimer's tests are often prohibitively expensive, require specialized equipment, and are limited to analyzing a few biomarkers at a time. In contrast, the 5ADCSI test utilizes xMAP technology from Luminex, making it not only cost-effective but also easy to implement in various laboratory settings.

According to Dr. Ebrahim Zandi, an associate professor at the Keck School, the primary advantage of this test is its affordability and accessibility, potentially allowing for widespread annual screenings for Alzheimer's. Similar to how cholesterol and blood sugar tests function, the 5ADCSI can help identify individuals who may benefit from medication or lifestyle modifications to mitigate the risk of Alzheimer's.

As Dr. Zandi explains, the process of Alzheimer's development spans 10 to 20 years, during which proteins like amyloid and tau accumulate. An affordable blood test capable of early detection of these proteins could enable medical interventions long before symptoms manifest.

Development of the Blood Test

To create the 5ADCSI, researchers selected a set of biomarkers known to correlate with Alzheimer's disease progression: two forms of amyloid (A?40 and A?42), phosphorylated tau, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). The test was developed to accurately detect these biomarkers in blood samples using the xMAP technology, which employs color-coded beads coated with antibodies that specifically bind to the targeted biomarkers. When blood samples are introduced, the biomarkers adhere to the beads, and advanced imaging sensors gauge the colors emitted to quantify the biomarker levels.

In the initial study, the test was applied to assess Alzheimer's-related biomarkers in 63 blood samples from three distinct groups: 11 individuals diagnosed with Alzheimer's disease, 17 with mild cognitive impairment (a precursor to Alzheimer's), and 35 healthy participants. The 5ADCSI successfully identified the highest concentrations of biomarkers in the Alzheimer's group, followed by those with mild cognitive impairment. Notably, the p217Tau biomarker displayed a particularly strong correlation with the disease.

The researchers also applied the same testing methodology to cerebrospinal fluid (CSF) samples, which typically contain higher concentrations of Alzheimer's-related proteins but are more challenging and costly to collect. They observed moderate to strong correlations between blood and CSF results, indicating that the blood test is sufficiently sensitive for early detection.

From Research to Clinical Application

The 5ADCSI test originated as a response to a practical need identified by Dr. Christopher Beam, who sought a more economical method for measuring Alzheimer's biomarkers in cognitive aging studies. Dr. Zandi's 5ADCSI provided the necessary solution.

The research team is now focused on further developing the technology and validating its efficacy as a clinical diagnostic tool. Future plans involve testing the accuracy of the 5ADCSI in a larger cohort comprising several hundred patients across varying stages of Alzheimer's disease.

The vision is for this test to become widely utilized, particularly since it employs technology that is both affordable and accessible globally, even in developing regions. Dr. Zandi's long-term aspiration includes the creation of a comprehensive brain health risk assessment that combines the 5ADCSI with genetic testing for the APOE4 variant, a gene associated with increased Alzheimer's risk, allowing individuals to better understand their susceptibility to the disease.