Enteral protease inhibition reduces systemic enzymatic activity and proteolysis after experimental trauma-hemorrhagic shock
Authors: Dos Santos Fernando , LI Joyce , O'Donoghue Anthony , Kistler Erik 
Published: May 2023

Trauma-hemorrhagic shock (T-HS) is a major cause of multiorgan failure and mortality world-wide. Our previous work demonstrates that uncontrolled proteolysis in T-HS is associated with poor outcomes and that enteral inhibition of proteolytic activity may be beneficial. However, the enzymes involved, their degradation products, and the systemic consequences of protease activity in T-HS are not well understood. Our aim was to identify plasma enzymatic activity and the resulting peptidome in experimental T-HS, and determine the changes in this activity following enteral protease inhibition. Anesthetized male Wistar rats (~400g) were subjected to T-HS via laparotomy followed by blood removal to achieve a mean blood pressure of ~35-40mmHg for 90 min. An orogastric catheter was passed through the mouth into the proximal duodenum and Golytely (Shock-control, n=8) or Golytely+gabexate mesilate, 10mg/kg (GM-treated, n=8) was enterally infused starting 30 minutes into the shock period. Animals were resuscitated with Lactated Ringers solution (LR) and monitored for 120 min after reperfusion. The gabexate mesilate treatment improved mean arterial pressure after reperfusion (57.6±4.3 mmHg) compared to Shock-control group (43.7±4.5mmHg, p<0.0001) requiring significantly less resuscitation fluid (14±3ml vs 25.7±2.3 ml, respectively, p<0.0001). Systemic proteolysis, as measured by the plasma peptidome, increased by 630±212% in the Shock-control group compared to baseline, and was mitigated by treatment with gabexate mesilate to 203±70% (p=0.02). Using tagged fluorescent substrates, trypsin-like activity in plasma increased with T-HS to 937±90% of baseline (p<0.0001) and was reduced by enteral protease inhibition to 321±72% of baseline (p=0.0321 vs. baseline, p=0.0078 vs. Shock-control). The most common proteins to be degraded were structural (myosin, actin, and collagen), coagulation-related (inter-alpha trypsin inhibitor, kininogen, complement C4, and fibrinogen) and metabolic in function (apolipoprotein E, fructose-bisphosphate aldolase, and carbonyl reductase). These proteins were cleaved after T-HS 1.5-4 times more in the Shock-control compared to the GM-treated group. In conclusion, we were able to identify trypsin-like activity in plasma from animals subjected to T-HS. Enteral inhibition of serine proteases was able to significantly decrease this activity and improve outcomes, suggesting that the gut is a driver of uncontrolled proteolysis and resulting morbidity in T-HS. Enteral serine protease inhibition may be an effective clinical strategy for decreasing inappropriate systemic proteolysis and improving outcomes in T-HS. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs and the Defense Health Agency J9, Research and Development Directorate under Award No. W81XWH-17-2-0047. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.