Mechanosensing via the Endothelial Glycocalyx
It is well known that endothelial cells in general sense fluid shear stresses and pressures. One way that these forces are transmitted is by the displacement of membrane proteins which in turn generate biochemical cascades within the cell. To understand how fluid forces regulate endothelial function, one must first characterize the flow near the endothelial cell membrane. This flow depends upon the density and structure of the endothelial surface layer (ESL). We allowed for variations in height and density of the layer, and numerically calculated the resulting flow rates using a Brinkman model. We found that such heterogeneities can significantly alter the flow rates within the ESL as well as the shear stresses felt at the cell membrane. To complement the numerical simulations, we constructed dynamically scaled physical models of the ESL of varying density and geometry. Flow velocities and shear stresses were calculated using particle image velocimetry. The results show good agreement with the numerical simulations.
Movies – Simulations & Experiments
Previously, we have visualized flow through physical models of the glycocalyx with the use of dyes. This method presents a number of problems, such as clouding the fluid in the tank as seen in the video below. We are in the process of upgrading to hydrogen bubble methods and piv. Please check back for improved videos.