Determinants of normal and increased microvessel permeability

The molecular structures which determine the normal permeability properties of the capillary wall and modulate changes in microvessel permeability include the cell surface glycocalyx, the junctional strands in the cleft between the adjacent endothelial cells, and the endothelial cell attachment sites to the extracellular matrix. To evaluate the role of the glycocalyx and junctional strand geometry as determinants of normal permeability properties, a 3D model was developed for water and solute flow through the cleft between the adjacent cells. To identify the very small pore pathway, a time-dependent diffusion model was developed for analysis of concentration profiles of electron dense small tracers in the interendothelial clefts.