BIOPHYSICAL THEORY AND MODELING |
EFFECT OF THE STRESS PHASE ANGLE ON THE STRAIN ENERGY DENSITY OF THE ENDOTHELIAL PLASMA MEMBRANE
Shigeru TADA 1, Cheng Dong 2 and John M Tarbell 3*
1 National defense academy
2 Pennsylvania State University
3 City College of New York/CUNY
* To whom correspondence should be addressed. E-mail: tarbell{at}ccny.cuny.edu.
Submitted on November 13, 2006
Revised on February 5, 2007
Accepted on 29 June 2007
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Abstract |
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Endothelial cells are simultaneously exposed to the mechanical forces of fluid wall shear stress (WSS) imposed by blood flow and solid circumferential stress (CS) induced by the blood vessel's elastic response to the pressure pulse. Experiments have demonstrated that these combined forces induce unique endothelial biomolecular responses that are not characteristic of either driving force alone and that the temporal phase angle between WSS and CS, referred to as the stress phase angle (SPA), modulates endothelial responses. In this paper, we provide the first theoretical model to examine the combined forces of WSS and CS on a model of the endothelial cell plasma membrane. We focus on the strain energy density of the membrane that modulates the opening of ion channels that can mediate signal transduction. The model shows a significant influence of the SPA on the strain energy density at the upstream and downstream ends of the cell where mechanotransduction is most likely to occur.
Key Words:
endothelial cell, mechanotransduction, shear stress, strain energy, stretch
