Objective: There is evidence that endothelin (ET) 1 affect neutrophil functions and that patients with severe acute pancreatitis have increased plasma levels of ETs. Under appropriate conditions, neutrophils are able to injure the endothelium. In the present study, we compared healthy donors with acute pancreatitis patients for neutrophil degranulation and its ability to injure the endothelium and the contribution of ET-1 to this injury.
Methods: Injury was evaluated by measuring the detachment of endothelial cells (ECV-304) growing in monolayer in coculture with human neutrophils for 4 hours. Neutrophil degranulation was assessed by myeloperoxidase (MPO) activity in coculture supernatants. In some experiments, neutrophils were pretreated with the antagonist of ET(A) receptor (BQ-123, 10(-6) M), which has high affinity for ET-1.
Results: Neutrophils from both healthy donors and acute pancreatitis patients caused detachment of endothelial cells, and levels of MPO activity were increased in coculture supernatants. Neutrophils from acute pancreatitis patients caused significantly higher levels of detachment and MPO in the supernatants. Pretreatment of neutrophils with BQ-123 inhibited the detachment caused by neutrophils from healthy donors but not by neutrophils from acute pancreatitis patients.
Conclusions: These results show that neutrophils taken from healthy donors damage the endothelium by a mechanism dependent on ETs acting via ET(A) receptor, whereas neutrophils from acute pancreatitis patients cause more severe damage that is not dependent on ETs in the in vitro system used.