Relocalization of endothelial cell beta-catenin after coculture with activated neutrophils from patients undergoing cardiac surgery with cardiopulmonary bypass.

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with neutrophil activation, inflammation, and consecutive edema. The impairment of endothelial junction molecules, and thus, hyperpermeability elicited by the interaction of activated neutrophils with endothelial cells may be important in this regard. Cocultures with human endothelial cells and neutrophils from 10 cardiac surgery patients with CPB were used to evaluate the role of neutrophils in modifications of the endothelial zonula adherens molecules VE-cadherin and beta-catenin. Laser scan microscopic analyses showed that neutrophils, which were isolated after the beginning of CPB, significantly impaired intracellular redistribution of endothelial beta-catenin with regard to membrane association (p <.0002) and staining pattern (p <.0001). VE-cadherin localization was not found to be significantly modified. Western blots with total cell extracts showed that amounts of beta-catenin did not vary significantly after co-culture with activated neutrophils. Activated neutrophils during cardiac surgery with CPB may induce endothelial dysfunction by impairing beta-catenin localization and thus contribute to endothelial hyperpermeability.