Influence of Hypothermia and Cardioplegic Solutions on Expression of α-Gal Epitope on Porcine Aortic Endothelial Cells

Abstract

bjectives: The Galα1-3Galβ1-4GlcNAc-R is the major antigen on pig tissue bound by human xenoreactive natural antibodies in xeno­transplant. We have investigated in vitro the influence of hypothermic storage with cardioplegic solutions on expression of Galα1-3Galβ1-4GlcNAc-Rs and hyperacute xenograft rejection.

Materials and Methods: To analyze effects of hypothermia on the Galα1-3Galβ1-4GlcNAc-Rs, cultured porcine aortic endothelial cells were exposed to a temperature of 4°C for 1 hour, 4 hours, and 6 hours. Cell cultures of the control groups were incubated at the same time at 38°C. To investigate the influence of cardioplegic solutions on the Galα1-3Galβ1-4GlcNAc-Rs, porcine aortic endothelial cells were exposed to 4°C for 4 hours in the presence of University of Wisconsin solution or histidine-tryptophan-ketoglutarate solution. Cells of the control groups were cooled at 4°C for 4 hours without cardioplegic solution. After treatment, porcine aortic endothelial cells were submitted to fluorescence-activated cell sorter.

Results: Hypothermia of 4°C showed no significant effect on the quantity of Galα1-3Galβ1-4GlcNAc-Rs. However, the treatment of porcine aortic endothelial cells with University of Wisconsin solution resulted in a highly significant reduction of Galα1-3Galβ1-4GlcNAc-Rs by 50% (P = .006). Treatment of porcine aortic endothelial cells with histidine-tryptophan-ketoglutarate solution decreased α-Gal quantity significantly by 32% (P = .011).

Conclusions: Our data offer new perspectives in the prevention of hyperacute, humoral xenograft rejection by reducing the Galα1-3Galβ1-4GlcNAc-Rs after exposure to different cardioplegic solutions.