Failed induction of heme oxygenase 1 in endothelial cells exposed to the hemoglobin based oxygen carrier Oxyglobin.

We investigated the effect of the bovine hemoglobin based oxygen carrier HBOC-200 (Oxyglobin) in rat aortic endothelial cells (RAEC) on the activation of heme oxygenase 1 (HO-1). RAEC were incubated in the presence of 75 microM (G1) or 225 microM (G2) HBOC-200. The positive control (G3) was performed by incubation with 50 microM Hemin. For negative control (G4) cells were incubated with medium alone. G2 and G3 reached a significant increase of bilirubin concentration compared to G4. A positive HO-1 signal in the Western Blot was seen in G3 12 and 24 h after incubation. The Western Blot of G1, G2 and G4 showed no HO-1 signal. These data suggest that HBOC-200 in the applied dosage cannot induce HO-1 expression in RAEC, and may be degraded by isoenzymes at a lower level.