Red Blood Cell Dynamics in Healthy and Cancer-Influenced Venular Flow: Role of Flow Conditions and Cell Stiffness.

Abstract

Background: Hemodynamic alterations in microvessels under pathological conditions such as cancer can modify RBC dynamics and near-wall behavior, influencing the cell-free layer and local flow microenvironment.

Methods: Three-dimensional simulations of two red blood cells with different stiffness levels were performed in venular flow under conditions representing a healthy individual and a breast cancer patient. The simulations were carried out using a force-coupling immersed-boundary lattice Boltzmann framework. RBC deformation, longitudinal and radial migration, velocity distribution, shear rate, and pressure fields were analyzed using hematocrit data, with blood viscosity derived from these data.

Results: Compared with healthy flow, cancer-affected conditions led to reduced RBC deformation and diminished radial migration, resulting in increased near-wall residence. This effect was more pronounced for the stiffened RBC. It was accompanied by a local reduction in near-wall velocity, an increase in shear rate, and larger pressure differences across the cell. Shear rate was higher in cancer-affected flow, while near-wall variations were reduced.

Conclusions: The results indicate that cancer-associated changes in venular flow promote RBC near-wall localization and may suppress CFL formation, primarily due to reduced RBC deformation, overriding low-hematocrit dilution. Circulating tumor cells were not modeled; however, RBC dynamics suggest a microenvironment that may facilitate near-wall interactions.