Home Medizin Die Studie unterstreicht das Potenzial von p-Tau217-Tests für klinische Studien und Diagnosen zur Alzheimer-Krankheit

Die Studie unterstreicht das Potenzial von p-Tau217-Tests für klinische Studien und Diagnosen zur Alzheimer-Krankheit

von NFI Redaktion

In a recent study published in eBioMedicine, researchers compared the performance of two commercial Phospho-Tau217 (p-Tau217) assays.

Study: Comparison of two plasma p-tau217 assays for detection and monitoring of Alzheimer's pathology. Image source: UnderhilStudio/Shutterstock.comStudy: Comparison of two plasma p-Tau217 assays for detection and monitoring of Alzheimer’s pathology. Image credit: UnderhilStudio/Shutterstock.com

Background

The quantification of Tau and Amyloid pathologies has enabled the diagnosis of Alzheimer’s disease (AD). Recent reports on blood-based biomarkers have the potential to change the landscape of AD diagnosis. With the increasing availability of disease-modifying treatments for AD, there is a need for accessible, scalable biomarkers.

To assess suitability for anti-amyloid treatments, determining Amyloid pathology through biomarker investigations is necessary.

Additionally, plasma biomarkers can aid in identifying advanced Tau pathology. p-Tau217 is a potential blood-based biomarker for AD, showing strong correlations with Tau and Amyloid pathologies, diagnostic performance, and equivalence with established cerebrospinal fluid (CSF) biomarkers.

Determining the consistency of specific p-Tau217 biomarkers in AD detection will enhance their clinical utility.

About the Study

In the present study, researchers compared the diagnostic performance of the Janssen p-Tau217+ assay and the ALZpath p-Tau217 assay. The analyses were conducted on a practical sample from the „Translational Biomarkers of Aging and Dementia“ (TRIAD) cohort.

The study included participants with Tau and Amyloid Positron Emission Tomography (PET) imaging and plasma samples for p-Tau217 assays. Data collection took place from October 2017 to August 2022.

Clinical diagnosis was conducted in the cohort prior to collecting biomarker data; cognitively unimpaired individuals (CU) had a Clinical Dementia Rating (CDR) and Mini-Mental State Examination score of 0 and > 24, respectively.

Participants with mild cognitive impairment (MCI) had a CDR score of 0.5. Participants with AD dementia had a CDR score ≥ 0.5. Non-AD patients were individuals with dementia but without Amyloid pathology on PET.

p-Tau217 tests were conducted in plasma (ALZpath and Janssen) and cerebrospinal fluid (CSF) (ALZpath). PET imaging data and participants‘ magnetic resonance imaging (MRI) were processed. Standardized uptake value ratios (SUVRs) for Tau and Amyloid-beta (Aβ) were calculated. SUVR ≥ 1.24 indicated Tau positivity.

Regional Tau PET was quantified in neocortical and medial temporal regions. Additionally, participants were classified into PET-based Braak stages.

Gender ratios and age were compared between groups using chi-square tests and analysis of variance. Spearman rank tests determined correlations between biomarkers.

Covariance analysis was conducted to compare biomarker values between groups, adjusting for gender and age. Voxelwise regression analyses were performed to explore associations between plasma markers and Tau and Amyloid PET, adjusted for gender and age.

Results

The researchers included 294 participants. p-Tau217 concentrations were evaluated in young individuals, older CU adults, MCI participants, individuals with AD dementia, and those with non-AD neurodegenerative conditions. Plasma levels of p-Tau217 increased with clinical severity.

Both tests showed robust correlations with CSF p-Tau217 and Amyloid PET SUVR. Voxelwise analyses revealed that both tests exhibited similar topographical association patterns between plasma Amyloid PET and p-Tau217.

Similarly, both tests strongly correlated with Tau PET in neocortical and medial temporal regions; they also correlated well with Tau PET SUVR.

Voxelwise analyses showed that both tests displayed similar topographical association patterns between plasma p-Tau217 and Tau PET.

Both plasma p-Tau217 tests agreed in 92% of cases. Furthermore, both tests showed remarkable concordance in identifying Amyloid PET positive participants and those with AD defined by biomarkers.

The diagnostic performance of plasma biomarkers in identifying Amyloid PET positivity in CU individuals and AD in individuals with cognitive impairment was evaluated. Both tests effectively recognized Amyloid PET positivity and biological AD.

A subset of participants had plasma and Tau PET data at least one other time point, allowing for the calculation of annual changes in biomarkers. The annual changes in plasma p-Tau217 tests correlated well with annual changes in neocortical Tau PET.

Conclusions

The researchers compared two p-Tau217 assays and found strong and similar associations with neocortical Amyloid PET.

Their diagnostic performance was identical in terms of Amyloid PET positivity in asymptomatic individuals and Tau and Amyloid positivity in individuals with cognitive impairment. The results suggest that p-tau217 assays could be suitable for diagnosing and monitoring AD pathology.

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