Abstract P127: Resuscitation with Liposome-Encapsulated Hemoglobin (Artificial Oxygen Carrier) from Lethal Hemorrhagic Shook and Its Effect on Nitoric Oxide and Tissue Expression of Hypoxia-Inducible Factor-1 alpha
Previously reported acellular hemoglobin-based oxygen carriers have a high affinity for nitric oxide (NO) and subsequently cause vasoconstriction leading to decrease peripheral perfusion due to NO scavenging effect. Unlike acellular hemoglobin, liposome-encapsulated hemoglobin (LHb) has lipid bilayer membranes that are similar to mammalian red blood cells (RBCs) and prevents hemoglobin from having any direct contact with the endothelium so that LHb can serve as blood substitutes comparable to RBC. The excellent resuscitation effect of LHb in severe hemorrhage is expected. Thus, we performed graded blood exchange experiment up to 85% blood loss in 45 rats. Under sevofrane-anesthesia, 15 rats were gradually exchanged blood with 5% albumin (Alb-group) while 15 rats exchanged with washed rat RBC (RBC-group) and 15 rats exchanged with LHb (LHb-group). The changes in NO metabolites (plasma NOx) and tissue expression of hypoxia-inducible factor-1 alpha (HIF-1) in the heart, kidney and liver were measured. All rats died in Alb-group whereas all survived for following 24-hours in RBC-group and NRC-group. NOx levels were identical during each resuscitation groups (Figure 1⇓). HIF-1 was only expressed in Alb-group (Figure 2⇓).
Conclusions: LHb transfusion is very effective in rescuing rats undergoing progressive hemodilution from lethal organ hypoxia without scavenging NO.