Rheology Update How to apply in clinics ? Inje University Sanggye Paik Hospital Lee, Byoung-Kwon MD, PhD Review • Hemorheologic parameters – Blood Viscosity ; Plasma, Whole blood – RBC deformability – RBC aggregability • CFD(computational fluid dynamics) – Shear rate, Shear stress – Fluid velocity – Computational Simulation Review Viscosity (cP) Intermolecular interactions 100 Rouleaux Sticky platelet? Immunoglobulins Rouleux formation Platelet aggregation Plasma proteins CRP? Cholesterol Viscosity Whole Blood Viscosity correlates RBC deformability & aggregation 10 Hematocrit Lipids Plasma 1 Low Shear 10 High shear 100 Shear rate (s-1) 400 How the viscosity acts? Change the blood flow, shear pattern 1. Affect to Atherogenesis, Circulation (micro-, macro-vascular) 2. Affect to Plaque rupture (acute ischemia) 3. Conformational change, mechanotrasduction, etc Change the Vessel wall including Endothelium Application example Fluid Dynamics in Lt. Main bifurcation Model Lt. Main bifurcation Modelling Marginal condition by Doppler Blood Viscosity Model     (o   )1  ( ) 2  q 1 2 1 whole blood viscosity ( Pa. s ) : Normal subject : Model 1 : Model 2 : Model 3 0.1 0.01 0.001 0.01 0.1 1 10 shear rate(s -1) 100 1000 10000 Flow pattern in normal viscosity Normal status Flow pattern in increased viscosity Increase viscosity at low shear rate Increase viscosity at both shear rate Increase viscosity at high shear rate 0.14s Normal subject Model 1 Model 2 Model 3 0.17s 0.20s 0.23s 0.14s Normal subject Model 1 Model 2 Model 3 0.17s 0.20s 0.24s WSS pattern in normal viscosity WSS pattern in model 1 WSS pattern in model 2 WSS pattern in model 3 WSS pattern in Normal vs. Model 1 WSS pattern in Normal vs. Model 2 WSS pattern in Normal vs. Model 3 Restenosis model WSS & Flow pattern in restenosis model The injured endothelial cells by the oscillating shear stress Pulsatile Blood Flow Endothelial cell torn off by high shear Flow Denuded intima Pulsatile Blood flow Low shear stress -oscillating flows Recirculating, turbulent flows Wall Round-shaped endothelial cells Leaky junction JAMA Vol. 282 Dec, 1999 Biorheology of cell-cell interactions Cell signaling, cell-cell or cell-matrix, tumor microenvironment, cancer immunology, etc. Applications of micro/nano biotechnology Rheological issues relevant to BioMEMS and their applications such as nano particles, drug delivery, diagnostic devices, etc. Molecular biomechanics and biorheology Rheological correlates of molecular structure, molecular responses to rheological forces, etc. Biorheology of mechanotransduction Mechano-biology, vascular responses to shear forces, force-induced signaling, etc. Biorheology of tissues and biomaterials Bone, scaffold tissue, tissue mechanics, blood vessels, tissue substitutes, etc. Microcirculation and hemorheology Tissue perfusion, flow and RBC distribution, lymphatics, vascular wall, correlations with in vitro data, etc. Basic hemorheology Blood cell mechanics, RBC aggregation and deformation, theoretical modeling, flow studies, new hemorheological methods, model studies, etc. Clinical hemorheology Hemorheological alterations in specific diseases, pregnancy and neonates, hematological disorders (e.g., sickle cell anemia, malaria), effects of exercise, etc. Thrombosis and coagulation Platelet aggregation, effects of RBC aggregation, fluid mechanical effects, etc. Rheology of stem cells Structure/function relations, targeted delivery, cell mechanics etc. Rheological issues in design of artificial organs Blood viscosity, blood cell damage, complement activation, circulating adhesion molecules, etc. Welcome to http://www.hemorheology.org/