HAI Book 2025 - Flipbook - Page 158
Bellaver, Bruna
23
Head-to-head trajectories of tau PET and plasma p-tau217 as a
function of Aβ
Bruna Bellaver1, Guilherme Povala1, Pamela L. Ferreira1, Guilherme Bauer-Negrini1, Firoza
Lussier1, Livia Amaral1, Carolina Soares1, Andreia Rocha1, Joseph Masdeu2, Dana Tudorascu1,
David Soleimani-Meigooni4, Juan Fortea5, Val Lowe6, Hwamee Oh7, Belen Pascual2, Brian A.
Gordon8, Pedro Rosa-Neto9, Suzanne Baker3, Tharick A. Pascoal1
1
University of Pittsburgh, Department of Psychiatry, PA, United States of America, Pittsburgh, PA, US
Houston Methodist Research Institute, Department of Neurology, Houston, TX, United States of America, Houston,
TX, US
3
Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America, Berkeley, CA, US
4
University of California San Francisco, Memory and Aging Center, San Francisco, CA, United States of America, San
Francisco, CA, US
5
Hospital de la Santa Creu i Sant Pau, Sant Pau Memory Unit, Department of Neurology, Barcelona, Spain, Barcelona,
ES
6
Mayo Clinic, Department of Radiology, Rochester, MN, United States of America, Rochester, MN, US
7
Brown University, Department of Psychiatry and Human Behavior, Providence, RI, United States of America,
Providence, RI, US
8
Washington University in St. Louis, Department of Radiology, St. Louis, MO, United States of America, St. Louis, MO,
US
9
Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Douglas Research
Institute, Montréal, QC,, Montreal, CA
2
Background: Tau PET tracers present distinct binding characteristics that might influence their trajectories and
relationship with other biomarkers along the AD continuum. In a head-to-head study, we investigated the
relationship between the emergence of PET tracers MK6240 and Flortaucipir, and plasma p-tau217 abnormalities
as a function of A´ PET deposition. We further assessed the concordance between tau PET and plasma p-tau217
positivity.
Methods: We assessed 353 individuals from the HEAD study (205 cognitively unimpaired and 148 cognitively
impaired) with A´ PET, MK6240 and Flortaucipir tau PET, and plasma p-tau217 (AlzPath) measures. Tau PET and
plasma p-tau217 trajectories were modeled as functions of A´ burden (Centiloid scale) using the Lowess method.
Biomarkers were z-scored using young individuals (n=19,
90%;
Fig. 2C). Fig. 3 shows representative images of four cases with discordant tau PET/p-tau217 status.
Conclusions: MK6240 becomes abnormal at lower levels of A´ burden compared to plasma p-tau217 and
Flortaucipir. The relatively high prevalence of discordant tau PET positive or plasma p-tau217 positive suggests
that some individuals may show tau PET positivity first, while others may exhibit plasma p-tau217 positivity first.
HAI2025 - 158
