Pulsatility protects the endothelial glycocalyx during extracorporeal membrane oxygenation

Abstract

Background Pulsatile flow protects vital organ function and improves microcirculatory perfusion during extracorporeal membrane oxygenation (ECMO). Studies revealed that pulsatile shear stress plays a vital role in microcirculatory function and integrity. The objective of this study was to investigate how pulsatility affects wall shear stress and endothelial glycocalyx components during ECMO. Methods Using the i-Cor system, sixteen canine ECMO models were randomly allocated into the pulsatile or the non-pulsatile group (eight canines for each). Hemodynamic parameters, peak wall shear stress (PWSS), serum concentration of syndecan-1, and heparan sulfate were measured at different time points during ECMO. Pulsatile shear stress experiments were also performed in endothelial cells exposed to different magnitudes of pulsatility (five plates for each condition), with cell viability, the expressions of syndecan-1, and endothelial-to-mesenchymal transformation (EndMT) markers analyzed. Results The pulsatile flow generated more surplus hemodynamic energy and preserved higher PWSS during ECMO. Serum concentrations of both syndecan-1 and heparan sulfate were negatively correlated with PWSS, and significantly lower levels were observed in the pulsatile group. Besides, non-pulsatility triggered EndMT and endothelial cells exposed to low pulsatility had the lowest possibility of EndMT. Conclusion The maintenance of the PWSS by pulsatility during ECMO possesses beneficial effects on glycocalyx integrity. Moreover, pulsatility prevents EndMT in endothelial cells, and low pulsatility exhibits the best protective effects. The augmentation of pulsatility may be a plausible future direction to improve the clinical outcome in ECMO.