1265: EFFECTS OF ENTERAL PROTEASE INHIBITION ON COAGULATION PROTEOLYSIS AFTER TRAUMA-HEMORRHAGIC SHOCK

Introduction: Coagulopathy and uncontrolled proteolysis are frequent sequelae of circulatory shock, and are associated with poor outcomes. We have previously demonstrated that enteral protease inhibition improves hemodynamics and survival in experimental shock. However, the mechanisms of inappropriate systemic protease activity in shock are not well understood. Our aim was to identify the effects of enteral protease inhibition on plasma proteolysis by examination of the plasma peptidome in experimental trauma-hemorrhagic shock (T-HS). Methods: Anesthetized Wistar rats were subjected to experimental T-HS with laparotomy. An oral catheter was inserted into the proximal duodenum and either gabexate mesilate+Golytely (GM) (10mg/kg) (n=8) or Golytely as a vehicle (n=8) was enterally infused starting 30min into the hypotension period. Blood was removed to achieve a mean blood pressure (MAP) of 35-40mmHg for 90min before reperfusion with lactated Ringer’s to obtain a target MAP of ≥65mmHg. Blood was taken for mass spectrometry peptidomics analysis at baseline and 120min after reperfusion. Results: Plasma proteolysis was increased 8.8±0.9 fold in the Shock-control group, and was reduced to 2.0±0.2 times baseline values in GM-treated animals (p< 0.0001). Despite representing only 0.3% of all proteins found in the peptidome, fibrinogen fragments comprised 11.3% of all peptides recovered after T-HS in our model, and were often non-canonically cleaved. Enteral GM decreased proteolysis of other proteins involved in coagulation, including: C4 (increased 1092±131% from baseline in Shock-control vs 154±22% in GM-treated animals, p< 0.0001); Kininogen-1 (relative intensity 90.5±20.4 in Shock-control vs. 19.8±1.4 in GM-treated group, p< 0.0001); Protein C (118% in Shock-control vs. GM-treated animals, p=0.0012). In addition, fragments from inter-alpha-trypsin inhibitor were exclusively found in the Shock-control group, suggesting breakdown of anti-proteases in the blood after shock. Conclusions: Enteral protease inhibition with gabexate mesilate significantly reduced plasma proteolysis after experimental T/HS as measured by peptidomics, especially of proteins involved with coagulation. This approach opens new insights for the understanding and treatment of Trauma-hemorrhagic shock, particularly related to coagulopathies.