Computational and in vitro studies of blast-induced blood-brain barrier disruption

Mauricio Del Razo Sarmina, University of Washington

4:45 - 5:30

There is growing concern that blast-exposed individuals might develop neurological disorders later in life. Therefore, it is important to understand the dynamic properties of blast forces on brain cells.

In this study, we focus specifically on the endothelial cells that maintain the blood-brain barrier (BBB), which regulates the passage of nutrients into the brain and protects it from toxins in the blood. To better understand the effect of shock waves on the BBB we have investigated an in vitro model in which BBB endothelial cells are grown in transwell vessels and exposed in a shock tube, confirming

that BBB integrity is directly related to shock wave intensity.

It is difficult to directly measure the forces acting on these cells in the transwell container during the experiments, so we developed a computational tool to do so.

Two-dimensional axisymmetric Euler equations with the Tammann equation of state were used to model the transwell materials, and a high-resolution finite volume method based on Riemann solvers and the Clawpack software was used to solve these equations in a mixed Eulerian/Lagrangian frame.

Results indicated that the geometry of the transwell plays a significant role in the observed pressure time series in these experiments. We also found that pressures can fall below vapor pressure due to the interaction of reflecting and diffracting shock waves, suggesting that cavitation bubbles could be a damage mechanism. Computations that include a simulated hydrophone inserted in the transwell suggest that introducing a measuring instrument could significantly alter blast wave properties.