N-GLYCOLYLNEURAMINIC ACID AS A POSSIBLE TRIGGER FOR IMMUNE REJECTION OF EPOXY-TREATED XENO-PERICARDIAL HEART VALVE BIOPROSTHESES

Highlights Stabilization of bovine pericardial tissue by ethylene glycol diglycidyl ether does not remove the N-glycolylneuraminic acid contained in its structure, which is one of the most immunoreactive glycan xenoantigens; N-glycolylneuraminic acid can potentially cause early immune rejection of epoxy-treated bioprosthetic heart valves. Aim. To assess the presence of N-glycolylneuraminic acid (Neu5Gc) in an intact bovine pericardial tissue stabilized by ethylene glycol diglycidyl ether and in the leaflets of epoxy-treated bioprosthetic heart valves (BHV) explanted due to dysfunction. Methods . By means of immunochemistry (using anti-Neu5Gc antibodies), we studied the fragments of 5 samples of intact epoxy-treated bovine pericardium commonly used in cardiac surgery. Similarly, we examined the fragments of the leaflets of 8 epoxy-treated BHVs that lasted for different time periods (1 day to 68 months) and excised during reoperation. The native bovine pericardium and the leaflets of 3 human aortic valves (AV) removed during reoperation in patients with aortic stenosis were used as positive and negative controls, respectively. Results. Positive reaction for Neu5Gc was observed in intact epoxy-treated xenopericardium and BHVs excised 1, 2, 20 and 42 days after implantation. The tissue of BHV that had lasted 30 months was characterized by the faint presence of Neu5Gc. In the leaflets of AV and in BHVs, explanted after 34, 63 and 68 months, Neu5Gc was not detected. Conclusion. Stabilization of xenobiomaterial with ethylene glycol diglycidyl ether does not remove the Neu5Gc. This saccharide remains in the biological tissue of epoxy-treated BHV for about 2.5 years after implantation.