Innate immune response after resuscitation with hemoglobin-based oxygen carrier and recombinant factor VIIA in uncontrolled hemorrhagic shock in a swine model.

BACKGROUND: Rapid resuscitation with oxygen-carrying fluids is critically important in hemorrhagic shock (HS) combat casualties in remote areas where blood is not available. Hemoglobin-based oxygen carrier-201 (HBOC-201) has been shown to increase survival and reduce immune activation following HS in animal models. Recombinant factor VIIa (rfVIIa), a systemic hemostatic agent, is Food and Drug Administration approved for use in acute hemorrhage in hemophilic patients. The combination of HBOC-201 and rfVIIa may form the basis of a prospective multifunctional blood substitute and provide benefits in the rapid restoration of hemostasis, decreased inflammation and improved survival of HS combat casualties. In the present study, we evaluated innate immune responses in a swine model of uncontrolled HS following resuscitation with HBOC-201 +/- rfVIIa. MATERIALS: Thirty-two pigs underwent uncontrolled hemorrhage/liver crush injury, followed by resuscitation with five doses of HBOC-201 or HBOC + rfVIIa (90 microg/kg, or 180 microg/kg, or 360 microg/kg) and simulated 4 hours hospital arrival. Immune parameters were evaluated by flow cytometry and enzyme-linked immunosorbent assay. RESULTS: Survival differences to 72 hours of animals resuscitated with HBOC, HBOC + rfVIIa (90), (180), and (360) were not statistically significant and resulted in survival of 25%, 63%, 63% and 50%, respectively. At the prehospital phase all groups exhibited minimal immunomodulation, characterized by stable CD4/CD8 ratio, marginal increase of apoptosis and insignificant fluctuations of adhesion markers; increase of plasma cytokines was comparable across all groups, except tumor necrosis factor-alpha, that was significantly elevated in the HBOC group. CONCLUSION: HBOC-201 + rfVIIa triggered minimum immune activation in an uncontrolled HS swine and there was a nonsignificant survival benefit.

Immune effects of resuscitation with HBOC-201, a hemoglobin-based oxygen carrier, in swine with moderately severe hemorrhagic shock from controlled hemorrhage.

HBOC-201, a hemoglobin-based oxygen carrier, improved physiologic parameters and survival in hemorrhagic shock (HS) animal models. However, resuscitation from HS and the properties of different fluids influence immune responses. The aim of this study was to determine if HBOC-201 significantly alters immune function in traumatic HS. Anesthetized pigs underwent soft tissue injury, controlled hemorrhage of 40% of blood volume, and resuscitation with HBOC-201 or Hextend, or no resuscitation. Sequential whole-blood samples were collected for analyses of leukocyte differential (hematology analyzer), T-lymphocyte subsets (CD3, CD4, and CD8) (FACS), lymphocyte adhesion marker CD49d (alpha4-integrin) expression (FACS), plasma cytokines-tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-10-(ELISA), and lymphocyte apoptosis (annexin-V/propidium iodide staining) (FACS). Statistical analyses were performed by the mixed procedure. Total WBC counts decreased posthemorrhage in both resuscitation groups. Lymphocyte percentages decreased and PMN percentages increased around 4 h posthemorrhage in all groups. CD3 cells decreased in all groups, but CD4 and CD8 cells decreased only in the resuscitation groups. TNF-alpha levels were not detectable in any groups. IL-6 levels were similar across treatment groups (P > 0.05); however, IL-10 levels were higher in the HBOC group, as early as 1 h posthemorrhage (P = 0.04). Increases in lymphocytic CD49d expression levels and apoptosis occurred only in nonresuscitation and Hextend groups, respectively (P < or = 0.01). In comparison with Hextend, HBOC-201 had no significant adverse or beneficial effects on immune function in this model of moderately severe HS in swine, suggesting that it may be safe as a resuscitation fluid in HS patients.