Experimental measurements of transcapillary permeability of charged and neutral molecules of equal size suggest molecular charge is an important determinant of microvascular permeability. We investigate contributions of solute and barrier charge to capillary permselectivity in a continuum model of electrokinetic and convective transcapillary exchange. The exchange barrier is modelled with parallel plates representing endothelial cell surfaces and a bridging hexagonal array of posts representing glycocalyx fibers as described by Curry (1984) and Weinbaum et al. (1992). Cleft and post surfaces are held at constant zeta potential. For a single post bridging the region between two parallel plates, the linear Poisson-Boltzmann and modified Stokes equations are solved using boundary element computational methods for the electrostatic potential and convective velocity profile, respectively. For plate separation (130 A), post radius (6 A), Debye length (8 A) and zeta potential values (-60 mV) typical of plasma ultrafiltrate in a glycocalyx filled interendothelial cleft, the electrostatic potential decays with distance from the post surface, vanishing at approximately 5 Debye lengths. Thus, compared to neutral molecules, there is enhanced anionic and diminished cationic convective transport in this region near the post for negative zeta potentials characteristic of plasma membranes and glycocalyx. The effect is more pronounced near plate surfaces. This computational result demonstrates contributions of electrostatic forces to charged particle transport as observed in certain experimental studies.
| Bassingthwaighte, James B; Butterworth, Erik; Jardine, Bartholomew et al. (2012) Compartmental modeling in the analysis of biological systems. Methods Mol Biol 929:391-438 |
| Dash, Ranjan K; Bassingthwaighte, James B (2010) Erratum to: Blood HbO2 and HbCO2 dissociation curves at varied O2, CO2, pH, 2,3-DPG and temperature levels. Ann Biomed Eng 38:1683-701 |
| Bassingthwaighte, James B; Raymond, Gary M; Butterworth, Erik et al. (2010) Multiscale modeling of metabolism, flows, and exchanges in heterogeneous organs. Ann N Y Acad Sci 1188:111-20 |
| Dash, Ranjan K; Bassingthwaighte, James B (2006) Simultaneous blood-tissue exchange of oxygen, carbon dioxide, bicarbonate, and hydrogen ion. Ann Biomed Eng 34:1129-48 |
| Dash, Ranjan K; Bassingthwaighte, James B (2004) Blood HbO2 and HbCO2 dissociation curves at varied O2, CO2, pH, 2,3-DPG and temperature levels. Ann Biomed Eng 32:1676-93 |
| Kellen, Michael R; Bassingthwaighte, James B (2003) Transient transcapillary exchange of water driven by osmotic forces in the heart. Am J Physiol Heart Circ Physiol 285:H1317-31 |
| Kellen, Michael R; Bassingthwaighte, James B (2003) An integrative model of coupled water and solute exchange in the heart. Am J Physiol Heart Circ Physiol 285:H1303-16 |
| Wang, C Y; Bassingthwaighte, J B (2001) Capillary supply regions. Math Biosci 173:103-14 |
| Swanson, K R; True, L D; Lin, D W et al. (2001) A quantitative model for the dynamics of serum prostate-specific antigen as a marker for cancerous growth: an explanation for a medical anomaly. Am J Pathol 158:2195-9 |
| Swanson, K R; Alvord Jr, E C; Murray, J D (2000) A quantitative model for differential motility of gliomas in grey and white matter. Cell Prolif 33:317-29 |
Showing the most recent 10 out of 19 publications
