Use of plasma biomarkers for AT(N) classification of neurodegenerative dementias

Abstract

Objectives: All categories included in the AT(N) classification can now be measured in plasma. However, their agreement with cerebrospinal fluid (CSF) markers is not fully established. A blood signature to generate the AT(N) classification would facilitate early diagnosis of patients with Alzheimer's disease (AD) through an easy and minimally invasive approach.

Methods: We measured Aβ, pTau181 and neurofilament light (NfL) in 150 plasma samples of the Sant Pau Initiative on Neurodegeneration cohort including patients with mild cognitive impairment, AD dementia, frontotemporal dementia, dementia with Lewy bodies and cognitively normal participants. We classified participants in the AT(N) categories according to CSF biomarkers and studied the diagnostic value of plasma biomarkers within each category individually and in combination.

Results: The plasma Aβ composite, pTau181 and NfL yielded areas under the curve (AUC) of 0.75, 0.78 and 0.88 to discriminate positive and negative participants in their respective A, T and N categories. The combination of all three markers did not outperform pTau181 alone (AUC=0.81) to discriminate A+T+ from A-T- participants. There was a moderate correlation between plasma Aβ composite and CSF Aβ1-42/Aβ1-40 (Rho=-0.5, p<0.001) and between plasma pTau181 and CSF pTau181 in the entire cohort (Rho=0.51, p<0.001). NfL levels in plasma showed high correlation with those in CSF (Rho=0.78, p<0.001).

Conclusions: Plasma biomarkers are useful to detect the AT(N) categories, and their use can differentiate patients with pathophysiological evidence of AD. A blood AT(N) signature may facilitate early diagnosis and follow-up of patients with AD through an easy and minimally invasive approach.

Keywords: amyloid; csf.

Conflict of interest statement

Competing interests: DA is employed by Hospital de la Santa Creu i Sant Pau and received research grants from Pla Estratègic de Recerca i Innovació en Salut (PERIS SLT006/17/125), and from Instituto de Salud Carlos III (PI18/00435 and INT19/00016). He participated in advisory boards from Fujirebio-Europe and Roche Diagnostics and received speaker honoraria from Fujirebio-Europe, Roche Diagnostics, Nutricia, Esteve and from Krka Farmacéutica S.L. CD is employed by Université de Montpellier and CHU de Montpellier. LM is employed by Biomedical Research Institute Sant Pau. ST is employed by Biomedical Research Institute Sant Pau. TE is employed by Biomedical Research Institute Sant Pau. Declarations of interest: Dr Estellés is funded by a 'Río Hortega' research grant from the Institute of Health Carlos III. NZ is employed by Hospital de la Santa Creu i Sant Pau. IB is employed by Hospital de la Santa Creu i Sant Pau. MC-I is employed by Hospital de la Santa Creu i Sant Pau. II-G is supported by the Global Brain Health Institute (Atlantic Fellow for Equity in Brain Health and pilot award for global brain health leaders GBHI ALZ UK-21-720973) and the 'Juan Rodés' grant from the Institute of Health Carlos III (JR20/00018). MAS-S is employed by Hospital de la Santa Creu i Sant Pau. He is funded by a 'Juan Rodés' research grant from the Institute of Health Carlos III. MA is employed by Biomedical Research Institute Sant Pau. Dr Altuna is funded by a 'Río Hortega' research grant from the Institute of Health Carlos III. IS is employed by Hospital de la Santa Creu i Sant Pau. MBS-S is employed by Biomedical Research Institute Sant Pau. LV is employed by Fundació Catalana Síndrome de Down. SV is employed by Biomedical Research Institute Sant Pau. AS is employed by Biomedical Research Institute Sant Pau. JP is employed by Biomedical Research Institute Sant Pau. CH is employed by Université de Montpellier et CHU de Montpellier. JV is employed by CHU de Montpellier. SL is employed by the University and the Hospital of Montpellier. He participated in advisory boards from Fujirebio-Europe and Roche. TKK is employed by the University of Gothenburg. NA is employed by the University of Gothenburg. KB is employed by Gothenburg University and Sahlgrenska University Hospital. KB has served as a consultant, at advisory boards, or at data monitoring committees for Abcam, Axon, Biogen, JOMDD/Shimadzu. Julius Clinical, Lilly, MagQu, Novartis, Roche Diagnostics and Siemens Healthineers, and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program. HZ is employed by the University of Gothenburg, Sahlgrenska University Hospital and University College London. HZ has served at scientific advisory boards for Denali, Roche Diagnostics, Wave, Samumed, Siemens Healthineers, Pinteon Therapeutics and CogRx, has given lectures in symposia sponsored by Fujirebio, Alzecure and Biogen and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program. OB is employed by Biomedical Research Institute Sant Pau. Dr Belbin is funded by a 'Miguel Servet' research grant from the Institute of Health Carlos III. RB is employed by Hospital de la Santa Creu i Sant Pau and received research grants from Institute of Health Carlos III, Fundació Bancària Obra Social La Caixa and Fundació La Marató de TV3. He participated in advisory boards from Lilly and Nutricia, and he received speaker honoraria and travel funding from Novartis and Nutricia. JC is employed by Biomedical Research Institute Sant Pau and received research grants from Generalitat de Catalunya and from Institute of Health Carlos III. JF is employed by Hospital de la Santa Creu i Sant Pau and received research grants from Institute of Health Carlos III, Fundació La Marató de TV3, and Pla Estratègic de Recerca i Innovació en Salut (PERIS). AL is employed by Hospital de la Santa Creu i Sant Pau and received research grants from CIBERNED, Institute of Health Carlos III and Fundación BBVA. He participated in advisory boards from Fujirebio-Europe, Nutricia, Biogen, and received speaker honoraria from Lilly.

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