Functional hyperemia drives fluid exchange in the paravascular space [post]

Ravi Kedarasetti, Kevin L. Turner, Christina Echagarruga, Bruce J. Gluckman, Patrick J. Drew, Francesco Costanzo
2020 unpublished
The brain lacks a conventional lymphatic system to remove metabolic waste. It has been proposed that fluid movement through the arteriolar paravascular space (PVS) promotes metabolite clearance. We performed simulations to understand how arteriolar pulsations and dilations, and brain deformability affect PVS fluid flow. In simulations with compliant brain tissue, arteriolar pulsations did not drive appreciable flows in the PVS. However, when the arteriole dilated as in functional hyperemia,
more » ... onal hyperemia, there was a marked movement of fluid. Simulations suggest that functional hyperemia may also serve to increase fluid exchange between the PVS and the subarachnoid space. We measured blood vessels and brain tissue displacement simultaneously in awake, head-fixed mice using two-photon microscopy. These measurements showed that brain deforms in response to pressure changes in PVS, as predicted by simulations. Our results show that the deformability of the brain tissue needs to be accounted for when studying fluid flow and metabolite transport.Acknowledgements: This work was supported by NSF Grant CBET 1705854.
doi:10.21203/rs.3.rs-22610/v2 fatcat:tinbycp375b5hpp3pybhpdpire