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Tanycytes Identified as Brain-to-Blood Tau Clearance Pathway, Impaired in Alzheimer’s

Evidence from mice, patient biomarker ratios, postmortem tissue points to a mechanism that now needs larger, longitudinal tests.

Overview

  • The study published March 5 in Cell Press Blue shows that tanycytes move tau from cerebrospinal fluid into pituitary portal capillaries and onward to the bloodstream.
  • In mice, blocking tanycytic vesicular transport reduced CSF-to-blood tau efflux and increased tau accumulation in the brain.
  • CSF and plasma from 86 people with Alzheimer’s and 91 controls revealed lower plasma-to-CSF ratios of total tau and p‑tau181 in the disease group.
  • Postmortem analyses found severely fragmented tanycyte processes in Alzheimer’s brains along with vesicular-transport gene alterations by single-nucleus RNA sequencing.
  • Researchers cite potential therapeutic and biomarker implications tied to preserving tanycyte function, with cautions about modest cohorts, model limitations, and the need for longitudinal validation.