ATP Release by Red Blood Cells under Flow: Model and Simulations

Area of Science:

• Biophysics
• Cardiovascular Physiology
• Computational Biology

Background:

• Adenosine triphosphate (ATP) acts as a key signaling molecule in blood microcirculation.
• Red blood cells (RBCs) release ATP in response to mechanical stress and deformation, linking vessel geometry, flow conditions, and RBC mechanical properties to chemical signaling in vasomotor modulation.
• While in vitro studies have provided insights, the precise mechanism of ATP release in microcirculation remains unclear.

Purpose of the Study:

• To develop an analytical model for ATP release from RBCs.
• To couple ATP concentration with RBC dynamics, considering local shear stress and membrane shape change.
• To investigate ATP release in various geometries and flow conditions relevant to microcirculation.

Main Methods:

• Developed an analytical model for ATP release, integrating RBC dynamics and mechanical stress.
• Formulated the chemo-mechanical coupling problem using a lattice-Boltzmann approach.
• Numerically solved the model in straight channels and bifurcations under shear and Poiseuille flows.

Main Results:

• The model successfully reproduces existing experimental findings on ATP release.
• Identified that ATP release is significantly influenced by local shear stress and RBC shape deformation.
• Pinpointed a major contribution of ATP release when RBCs navigate network bifurcations.

Conclusions:

• The proposed model provides a consistent framework for understanding ATP release in microcirculation.
• The study elucidates the interplay between RBC mechanical properties and chemical signaling.
• Findings may aid in understanding vasomotor modulation and blood flow regulation.