Hippocampal atrophy over two years in relation to tau, amyloid-β and memory in older adults

Neurobiol Aging. 2025 Feb:146:48-57. doi: 10.1016/j.neurobiolaging.2024.11.007. Epub 2024 Nov 23.

Abstract

In this longitudinal brain imaging study, we aimed to characterize hippocampal tau accumulation and subfield atrophy relative to cortical amyloid-β and memory performance. We measured tau-PET in regions associated with Braak stages I to VI, global amyloid-PET burden, hippocampal subfield volumes and memory assessments from 173 participants aged 55-85. Eighty-six of these participants were tested again two years later. Tau-PET change in the Braak II region, corresponding to the hippocampus and the entorhinal cortex, was significantly associated with the cornu ammonis 1 (CA1) atrophy and memory score. This CA1 atrophy did not significantly mediate the association between tau and memory, nor did global amyloid-PET burden correlate with tau-PET changes in the Braak II region. Longitudinal hippocampal tau accumulation is amyloid-β-independent and co-localized with subfield atrophy. As tau-associated memory decline seems to be independent from hippocampal atrophy, other mechanisms could contribute to the deficit.

Keywords: Alzheimer’s disease; Hippocampal subfields; Hippocampus; Longitudinal; Memory; Tauopathy.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging / metabolism
  • Aging / pathology
  • Amyloid beta-Peptides* / metabolism
  • Atrophy*
  • Female
  • Hippocampus* / diagnostic imaging
  • Hippocampus* / metabolism
  • Hippocampus* / pathology
  • Humans
  • Longitudinal Studies
  • Male
  • Memory Disorders / diagnostic imaging
  • Memory Disorders / etiology
  • Memory Disorders / metabolism
  • Memory Disorders / pathology
  • Memory*
  • Middle Aged
  • Positron-Emission Tomography
  • Time Factors
  • tau Proteins* / metabolism

Substances

  • tau Proteins
  • Amyloid beta-Peptides