Increased levels of granular tau oligomers: An early sign of brain aging and Alzheimer's disease

Sumihiro Maeda, Naruhiko Sahara, Yuko Saito, Shigeo Murayama, Atsushi Ikai, Akihiko Takashima

Research output: Contribution to journalArticlepeer-review

243 Citations (Scopus)


Development of neurofibrillary tangles (NFTs) is a pathological hallmark in various neurodegenerative disorders including Alzheimer's disease (AD). Recently, we identified a granular tau oligomer having a pre-filamentous structure. To determine the role of this oligomer in NFT formation, we quantified the amount of granular tau oligomer in 21 frontal cortex samples, each displaying varying degrees of Braak-staged NFT pathology. Here we report that granular tau oligomer levels in frontal cortex were significantly increased, even in brains displaying Braak-stage I neuropathology, a stage at which clinical symptoms of AD and NFTs in frontal cortex are believed to be absent. This suggests that increases in granular tau oligomer levels occur before NFTs form and before individuals manifest clinical symptoms of AD. Increased granular tau oligomer levels, therefore, may lead to NFT formation in frontal cortex, eventually leading to the development of AD. Thus, increases in granular tau oligomer levels may represent a very early sign of NFT formation and AD.

Original languageEnglish
Pages (from-to)197-201
Number of pages5
JournalNeuroscience Research
Issue number3
Publication statusPublished - 2006 Mar 1
Externally publishedYes


  • Alzheimer's disease (AD)
  • Atomic force microscopy (AFM)
  • Braak stage
  • Brain aging
  • Granular tau oligomer
  • Tau

ASJC Scopus subject areas

  • General Neuroscience


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