Numerical analysis of cellular flow and adhesion in microcirculation
Complex systems and Biological physics seminar
Tuesday 17 October 2017
Naoki Takeishi (Osaka University, Japan)
Cell adhesion is a multistep process consisting of margination, tethering, rolling, and stable adhesion. Each intravital event is of crucial importance in both pathological and physiological processes such as leukocyte immune function and cancer metastasis. Because this process involves not only the biochemical interaction of adhesion proteins, but also the mechanics of cell and cellular environment, the biomechanics of cell adhesion has not been fully understood yet. In this study, we developed a numerical model of cellular flow and adhesion in microcirculation. The fluid mechanics of plasma and cytoplasm was coupled with the solid mechanics of cell membrane, and the ligand-receptor interaction of adhesion proteins. Our results suggested that the passing motion of red blood cells effectively induced the margination of leukocyte and also circulating tumor cell (CTC). We found that the cell velocity was faster than mean blood velocity even when the leukocyte and CTC were marginated. We also analyzed cell adhesion during “bullet motion” in capillaries. We showed that bullet motion effectively decreased the cell velocity. This result suggests that weak ligand-receptor bindings such as PSGL-1–P-selectin, which are responsible for leukocyte rolling, allow the cell to firmly adhere to the wall in capillaries. These results will gain insight into biomechanics of cell adhesion, and will be helpful for various clinical problems, for example, diagnosing a leukocyte immune response and cancer metastasis.
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