Fluid flow rate and shear stresses affect endothelial cell responses

Mechanical stimuli impact numerous cellular behaviors, including cell mitosis, chemotaxis, migration, differentiation, and extracellular matrix remodeling. While many studies exist on the role of chemical stimuli and mechanical properties in angiogenesis, the effect of flow-induced shear stress has not been investigated. Abdi and Vahidi proposed a model to describe cellular responses to shear and tensile stress induced by fluid flow.

Endothelial cells are in constant communication with mechanical signals from blood flow and the extracellular matrix. Changes in these signals can disturb vascular tissue development and stability, which may contribute to such pathological conditions as atherosclerosis, diabetes mellitus, tumor growth, and metastasis.

“A consolidated understanding of endothelial cell behavior can open paths for revealing the nature of many pathologies attributed to them,” said co-author Bahman Vahidi.

The Lattice Boltzmann method was used to calculate flow propagation and the Cellular Potts model to predict cellular responses. The resulting model reproduced vascular network formation and the elongation and migration of cells under laminar flow conditions.

Simulations showed the cells changing shape and moving to reduce the flow normal stress by increasing their area parallel to the direction of flow. The shear and tensile stresses induced by fluid flow were found to prompt vasculogenesis and lumen formation through passive endothelial modulations.

“We hope that improvement of these models can provide a better understanding of capillary sustenance, which could have clinical implications in ischemic diseases, including aneurysm, and retinal hypervascularization, as well as angiogenesis in tumors,” said Vahidi.

Source: “A vasculogenesis model based on flow-induced stresses on endothelial cells,” by Pooya Abdi and Bahman Vahidi, AIP Advances (2022). The article can be accessed at https://doi.org/10.1063/5.0087884 .