Resuscitation Fluids Modulate Sterile Inflammation in a Rodent Model of Hemorrhagic Shock

Abstract

Sterile inflammation may trigger an array of danger‐associated molecular patterns and activation of the vascular endothelium, leading to loss of vascular barrier, microvascular leakage, coagulation dysfunction, leucocyte extravasation and organ injury. In our rat hemorrhage model, we have demonstrated previously elevated cytokine levels in liver, kidney and lung along with circulating proteases and endothelial dysfunction following hemorrhagic shock (HS) and/or fluid resuscitation. We hypothesized that normal saline (NS) resuscitation after HS may sustain sterile inflammation by increasing leukocyte influx to tissues (transmigration) and net leukocyte recruitment (overall efficiency), which results in loss of barrier integrity and tissue injury, compared to HS alone or blood products. Anesthetized rats (n= 5–7/group) were bled 40% of blood volume and either left untreated (HS ONLY) for over 3h or resuscitated with NS, 45 ml/kg, or 5% Albumin (ALB), 15ml/kg. Shams rats (control) were subject to all procedures, except hemorrhage or resuscitation. Intravital microscopy was performed in over 100 cremaster venules to determine leukocyte transmigration and overall efficiency as well as blood flow, wall shear rate (WSR), endothelial glycocalyx thickness and vascular permeability. Post‐shock or post‐resuscitation blood and tissue samples were collected over 3h from onset of hemorrhage. Our HS model alone decreased blood flow and WSR more than 60% (vs. sham, P<0.05), and increased glycocalyx shedding, permeability as well as transmigrated leukocytes (vs. sham and ALB, P<0.05). High levels of transmigration post‐shock was sustained after NS (883 ± 433 transmigrated cells/mm2, vs. sham, P<0.05). Compared to HEM ONLY, IL‐1β, IL‐6 and TNF‐α levels in kidney were 2–3‐fold higher in NS group, as well as blood flow and WSR, glycocalyx shedding, permeability (P<0.05). The highest overall efficiency post‐shock was observed in NS group (224 ± 117 transmigrated cells/mm2 per 1,000 leukocytes/μL) vs. HS ONLY (164 ± 94, P=0.04), sham (113 ± 50, P<0.001) and albumin group. In contrast, ALB normalized glycocalyx, venular blood flow and WSR, as well as restored barrier function and decreased inflammation to sham levels, compared to HEM ONLY. Fluid administration presents a therapeutic conflict between hemodynamics stabilization and detrimental effects on the endothelial and microvascular function. Iatrogenic increase in leukocyte recruitment and migration into tissues after NS sustained sterile inflammation after hemorrhagic shock and thus presents some clinically relevant deleterious effects.Support or Funding InformationUSArmy Medical Research Materiel CommandThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.