Acute Degradation of the Endothelial Glycocalyx in Infants Undergoing Cardiac Surgical Procedures

Abstract

There is no doubt today about the existence of the endothelial glycocalyx (EG) and its decisive role in maintaining vascular homeostasis in adult humans. Shedding of the EG has been demonstrated in adults with sepsis or trauma, in patients undergoing major operations, and after ischemia/reperfusion. The aim of the present study was to demonstrate whether shedding of the EG also occurs in infants undergoing heart operations. Two major constituents of the EG (syndecan-1 and hyaluronan) were measured in the arterial serum of 42 infants during cardiac operations in a prospective observational study. The groups were defined according to the ischemic impact: cardiac operations with cardiopulmonary bypass under beating heart conditions (CPB group, regional ischemia of lungs, n= 10), operations with cardiopulmonary bypass and aortic clamping (CPB+AC group, regional ischemia of heart and lungs, n= 24), and cardiac operationswith deep hypothermic circulatory arrest (CPB+AC+DHCA group, whole-body ischemia, n= 8). Syndecan-1 and hyaluronan were detected in all infants, providing an indication for the presence of a glycocalyx. During the operations, no significant difference in syndecan-1 concentration was observed in the CPB group, but levels increased significantly in both other groups (maximum increases: CPB+AC 3.0-fold, CPB+AC+DHCA 3.7-fold, p < 0.05). Hyaluronan increased significantly in the course of the operation in all groups (maximum increases: CPB 1.2-fold, CPB+AC 1.4-fold, CPB+AC+DHCA 1.7-fold, p < 0.05). The present data provides the first evidence for basal turnover of vascular EG in infants. Similarly to the process in adults, the shedding of thisstructure increases with ischemia/reperfusion, the extentbeing dependent on the degree of ischemic challenge.