The Effects of Shear Stress on Endothelial Cells at Hypothermic Temperatures

Hypothermic machine perfusion preservation (MPP) has proven to be a successful technique for hypothermic kidney storage, however this technology has not successfully been applied to the liver. Recent research has indicated that the endothelial cells lining the liver sinusoids display rounding phenomena during MPP that is not fully understood. In order to gain a better understanding of endothelial cell shear stress response and the factors that induce rounding, a temperature-controlled micro-shear chamber has been designed and fabricated. The micro-shear chamber has been used to apply shear stresses, corresponding to those imposed during MPP, to rat liver primary endothelial cell cultures in order to form an understanding of how these stresses affect endothelial cell morphology. The chamber allows for the application of shear stresses ranging from 0.2 ± .01 dynes/cm² to 2.3 ± 0.3 dynes/cm², corresponding to what occurs during MPP.] Twenty-four hour in vitro experiments with shear stresses ranging from 0 to 1.49 dynes/cm² at 4 °C were conducted in order to replicate in vivo conditions of the liver during hypothermic MPP. It has been demonstrated that endothelial cell rounding increases with increasing shear and can be prevented by utilizing low flow rates.