New FACEHBI results support the effectiveness of a tool to measure blood amyloid levels

A study led by the laboratory Araclon Biotech-Grifols, in collaboration with Ace Alzheimer Center Barcelona, has evaluated the validity of the ABtest-MS method for the quantification of β-amyloid peptides in plasma in a cohort of individuals with subjective cognitive impairment of the Fundació ACE Healthy Brain Initiative (FACEHBI) project. The paper, published in the journal Alzheimer’s Research & Therapy, concludes that this is an accurate and cost-effective diagnostic tool for detecting early pathological changes in Alzheimer’s disease and the risk of clinical worsening.

The accumulation of amyloid protein is the first sign of Alzheimer's disease that can be reliably quantified using two well-established methods: cerebrospinal fluid (CSF) and positron emission tomography (PET). These methods are invasive, expensive and their availability is limited, which has led researchers around the world to look for other, more accessible and cost-effective methods, such as blood biomarkers. This is a major technical challenge, as the levels of this protein in the blood are not very high.

Now, the laboratory Araclon Biotech – Grífols has developed a new method to quantify the Aβ42/Aβ40 ratio using ABtest-MS, a technique that works by directly extracting Aβ peptides from plasma without the use of antibodies.

The study involved 200 subjects with subjective cognitive impairment (i.e. who have self-perceived cognitive impairment but who do not show objective cognitive impairment on neuropsychological assessment) from the FACEHBI project and allowed the association of plasma Aβ42/Aβ40 ratio, as quantified by ABtest-MS, with Alzheimer's disease-related brain changes: increased in vivo brain uptake of amyloid in PET, poorer cognitive performance in an episodic memory test, and higher degree of cerebral atrophy on MRI. In addition, plasma Aβ42/Aβ40 ratio levels predicted cognitive decline in these individuals (conversion to mild cognitive impairment) after two years of follow-up. These results have been validated in a Korean cohort (DPUK-Korean), which increases the scientific strength of these findings.

In summary, these data show that plasma amyloid levels have potential as a biomarker of early-stage Alzheimer's disease and that their measurement by ABtest-MS is affordable and accessible. These results are important because they support the use of this test as a screening tool in clinical trials of new drugs against Alzheimer's disease, in prevention strategies and also in clinical practice.

“It will be necessary to validate the results of this new tool in other cohorts, comparing it with other biomarkers and with greater follow-up over time,” says Dr. Marta Marquié, neurologist, deputy director of Ace's Clinical Research Program and leader of FACEHBI. “But these are positive results that bring us closer to a less invasive and expensive early diagnosis.”