Platelet activation by human pancreatic fluid.

The effects of human pancreatic fluid (HPF) on platelet aggregation and activation were studied. HPF, obtained at operation from nine patients with chronic pancreatitis and two with pancreas cancer, was pooled, lyophilized, and adjusted to a concentration of 1 mg protein/cc of 0.9% saline after dialysis. Platelet aggregation was evaluated by measuring platelet count after iv administration of HPF to five rabbits in concentrations ranging from 0.2 to 2.0 mg/kg. Platelet activation was evaluated by adding 0.1-ml aliquots of pooled HPF in various concentrations to 0.9 ml of human platelet-rich plasma. After a 15-min incubation at 37 degrees C, the platelets were removed by centrifugation and the supernatant examined for platelet-release products. Serotonin was measured by high-performance liquid chromatography (HPLC) and platelet factor 4 and thromboxane B2 were measured by radioimmunoassay. A significant decrease in rabbit platelet count signifying platelet aggregation was seen after iv administration of 1.0 mg/kg (P less than 0.05) and 2.0 mg/kg (P less than 0.001) HPF. Platelet activation was confirmed by a significant increase (P less than 0.05) in serotonin, platelet factor 4, and thromboxane B2 at almost all concentrations of HPF. This study indicates that HPF induces platelet aggregation and activation and suggests that platelet contact with pancreatic exocrine fluid may have both local and systemic effects that are important in the pathophysiology of acute pancreatitis.