A mathematical model for ATP-mediated calcium dynamics in vascular endothelial cells induced by fluid shear stress

In consideration of the mechanism for shear-stress-induced Ca2 influx via ATP(adenosine triphosphate)-gated ion channel P2X4 in vascular endothelial cells, a modified model is proposed to describe the shear-stress-induced Ca2 influx. It is affected both by the Ca2 gradient across the cell membrane and extracellular ATP concentration on the cell surface. Meanwhile, a new static ATP release model is constructed by using published experimental data. Combining the modified intracellular calcium dynamics model with the new ATP release model, we establish a nonlinear Ca2 dynamic system in vascular endothelial cells. The ATP-mediated calcium response in vascular endothelial cells subjected to shear stresses is analyzed by solving the governing equations of the integrated dynamic system. Numerical results show that the shear-stress-induced calcium response predicted by the proposed model is more consistent with the experimental observations than that predicted by existing models.