Brain amyloid-<i>&beta;</i> accumulation detected via plasma p-tau217

A multi-institutional prospective joint research group including Lecturer Takanobu Ishiguro of the Niigata University Medical & Dental Hospital and Professor Takeshi Ikeuchi of the Brain Research Institute at Niigata University, in collaboration with the Tokyo Metropolitan Institute for Geriatrics and Gerontology, Institute of Science Tokyo, Kudanzaka Hospital, Tokyo Medical University, Showa Medical University, Nishiniigata Chuo Hospital, the National Institute of Neuroscience at the National Center of Neurology and Psychiatry, the University of Tokyo, and Fujirebio Inc., has clarified that p-tau217 (phosphorylated tau protein at position 217 in plasma) can detect cerebral amyloid-β pathology for Alzheimer's disease (AD) with an accuracy comparable to that of cerebrospinal fluid (CSF) biomarkers. This achievement is expected to lead to a minimally invasive, efficient, and highly accurate diagnosis.

The results were published in Alzheimer's Research & Therapy on March 3. Conceptual diagram of the studyProvided by Professor Ikeuchi of Niigata University AD is the most frequent cause of dementia, characterized primarily by progressive memory loss alongside various other cognitive impairments. Molecular targeted drugs are applied for its treatment.

However, prior to the administrative use of these molecular targeted drugs, diagnoses via CSF tests or amyloid PET scans are required under insurance-covered medical care, creating a demand for less invasive and lower-cost blood biomarkers. While plasma p-tau217 had attracted attention as a powerful blood biomarker for detecting cerebral amyloid pathology in AD, its clinical utility had not yet been sufficiently validated. Therefore, the research group set out to verify this clinical utility through a multi-institutional prospective study.

Using plasma samples from 332 individuals, encompassing cognitively normal individuals and those with mild cognitive impairment, dementia due to AD, and non-AD dementia, they measured p-tau217 levels and concurrently measured Aβ42 in the blood to calculate the p-tau217/Aβ42 ratio. As a result, the plasma p-tau217 level and the p-tau217/Aβ42 ratio demonstrated increasingly higher values in the order of: cognitively normal individuals, non-AD dementia, mild cognitive impairment, and dementia due to AD. Within each clinical category, the plasma p-tau217 level and the p-tau217/Aβ42 ratio of cerebral-amyloid-positive individuals were significantly higher compared to those of amyloid-negative individuals.

Furthermore, the accuracy in detecting cerebral amyloid visualized by amyloid PET was extremely high, matching the accuracy of CSF biomarkers already in clinical use. Additionally, when they established two cut-off values satisfying a 90&percnt; sensitivity and specificity threshold (a high cut-off of 0.247 pg/mL and a low cut-off of 0.

134 pg/mL), the utility of plasma p-tau217 measurement as a screening test was demonstrated. It was revealed that by introducing this blood biomarker, approximately 40&percnt; of the subjects could be determined to have a low probability of cerebral amyloid accumulation, thereby reducing the number of required PET scans or CSF examinations. Ikeuchi stated: "The auxiliary diagnosis of Alzheimer's disease using plasma p-tau217 was previously conducted primarily for research purposes.

This study has demonstrated that plasma p-tau217 possesses sufficient performance even in actual clinical settings (the real world). We hope that the clinical application of plasma p-tau217 will progress in an appropriate manner moving forward." Journal Information Publication: Alzheimer's Research & Therapy Title: Prospective study on clinical utility of plasma p-Tau217 and other biomarkers in Japanese memory clinics using the LUMIPULSE platform DOI: 10.

1186/s13195-026-01997-7 Medicine This article has been translated by JST with permission from The Science News Ltd. (https://sci-news.co.

jp/). Unauthorized reproduction of the article and photographs is prohibited. This article has been translated by JST with permission from The Science News Ltd.

(https://sci-news.co.jp/).

Unauthorized reproduction of the article and photographs is prohibited.