Key blood disease indicator can be estimated with rheological blood test data

Oxygen-delivering red blood cells (RBCs) are deformable, which allows them to squeeze through even the smallest capillaries in our bodies. However, this deformability can be reduced by environmental conditions and is an indicator of some blood diseases including malaria and sickle-cell disease. Despite the importance of quantitatively knowing RBC deformability, no method exists to estimate it from blood test data.

Takeishi et al. created the first RBC deformability estimate that can be conducted with a blood sample. The study focused on determining if the RBC membrane shear elasticity — a marker of cell membrane flexibility — could be estimated from a single-cell mechanical stretch test, which can be determined from the viscosity of a blood sample. The researchers produced their estimate from an analysis of a rheological RBC suspension model along with macro-rheological data of human RBCs suspended in plasma. With a multi-scale numerical analysis, the researchers determined a statistical average of the RBC membrane shear elasticity of both single intact RBCs and hardened RBCs.

“Both estimated membrane shear elasticities of intact RBCs and hardened RBCs reproduced well the experimentally observed shear-thinning non-Newtonian behavior in these suspensions,” said author Naoki Takeishi. “We concluded that our complementary approach makes it possible to estimate the statistical average of individual RBC deformability from macro-rheological data obtained with usual rheometric tests.”

Since RBC shear elasticity can be caused by the cross-linking of membrane and intracellular proteins, their findings could also inform research on intracellular compounds important to organ-scale metabolism. Next, the researchers plan to extend their work to studying hardened cell suspensions and conditions leading to cell jamming.

Source: “Numerical-experimental estimation of the deformability of human red blood cells from rheometrical data,” by Naoki Takeishi, Tomohiro Nishiyama, Kodai Nagaishi, Takeshi Nashima, and Masako Sugihara-Seki, Journal of Rheology (2024). The article can be accessed at https://doi.org/10.1122/8.0000877 .