Brain fluid drains through membrane openings in mice
Tracer experiments mapped the route; in aged mice, a protein delivered through the nose restored lymph vessels and fluid clearance to normal.
Limit: Tracer movement served as a stand-in for cerebrospinal fluid drainage
Edited by Boris Djordjevic · AgingResearch.News
In experiments in mice, researchers tracked fluorescent tracers in cerebrospinal fluid, the fluid around the brain and spinal cord. The tracers passed through openings in a membrane surrounding the olfactory bulbs, structures involved in smell, and entered lymph vessels in the brain’s outer covering. These vessels passed through holes in the skull, joined lymph vessels in the nose and drained to lymph nodes in the neck. Similar membrane openings were found in cynomolgus monkeys.
In aged mice, reduced fluid outflow accompanied shrunken lymph vessels in the brain’s outer covering and nose, fewer membrane openings and smaller skull openings. Delivering vascular endothelial growth factor-C, a protein that supports lymph vessel growth, through the nose restored lymph vessels and fluid clearance to normal.
Why it matters
In mice, fluid clearance from around the brain declines with age. Mapping its exit route offers a way to investigate whether changes in surrounding membranes, bone and lymph vessels contribute to that decline.
Caveats
These animal experiments do not show whether the same approach would restore fluid clearance in people. The abstract does not report the protein dose or delivery duration.
The paper
CSF clearance through arachnoid fenestrations to olfactory meningeal lymphatics
Institute for Basic Science; Korea Advanced Institute of Science and Technology
Cell, Jul 21, 2026, Open access
