Plasma MTBR-tau243 biomarker identifies tau tangle pathology in Alzheimer’s disease
Kanta Horie, Gemma Salvadó, Rama K. Koppisetti, Shorena Janelidze, Nicolas R. Barthélemy, Yingxin He, Chihiro Sato, Brian A. Gordon, Hong Jiang, Tammie L.S. Benzinger, Erik Stomrud, David M. Holtzman, Niklas Mattsson, John C. Morris, Sebastian Palmqvist, Rik Ossenkoppele, Suzanne E. Schindler, Oskar Hansson, Randall J. Bateman
Abstract
Insoluble tau aggregates within neurofibrillary tangles are a defining neuropathological feature of Alzheimer’s disease (AD) and closely correlate with clinical symptoms. Although tau pathology can be assessed using tau positron emission tomography, a more accessible biomarker is needed for diagnosis, prognosis and tracking treatment effects. Here we present a new plasma tau species, the endogenously cleaved, microtubule-binding region containing residue 243 (eMTBR-tau243), which specifically reflects tau tangle pathology. Across the AD spectrum in three different cohorts (n = 108, 55 and 739), plasma eMTBR-tau243 levels were significantly elevated at the mild cognitive impairment stage and increased further in dementia. Plasma eMTBR-tau243 showed strong associations with tau positron emission tomography binding (β = 0.72, R2 = 0.56) and cognitive performance (β = 0.60, R2 = 0.40), outperforming other plasma tau (%p-tau217 and %p-tau205) biomarkers. These results suggest that plasma eMTBR-tau243 may be useful for estimating the tauopathy load in AD, thereby improving the diagnostic evaluation of AD in clinical practice and monitoring the efficacy of tau-targeted therapies in clinical trials. Plasma eMTBR-tau243 is a specific biomarker of tau tangles in Alzheimer’s disease and enables the detecting and tracking of Alzheimer’s clinical impairment.