CSF clearance through arachnoid fenestrations to olfactory meningeal lymphatics.

Arachnoid fenestrations around the olfactory bulbs enable CSF clearance via dural lymphatics, with 20-50% of tracers passing through these openings in mice and monkeys.

• Why it matters: Understanding the precise pathway of CSF clearance is crucial for addressing neurological diseases linked to impaired lymphatic drainage and aging-related decline in brain waste removal.
• What they did: The study used tracer experiments and imaging in mice and monkeys to identify arachnoid fenestrations, revealing their role in directing CSF from the subarachnoid space through dural lymphatics to cervical lymph nodes, and examined age-related changes.
• The result: Aging reduced CSF outflow and lymphatic structures, but intranasal VEGF-C restored lymphatic function and CSF clearance, highlighting potential therapeutic avenues for age-associated neurological conditions.