Effect of diaspirin cross-linked hemoglobin on normal and postischemic microcirculation of the rat pancreas

Microcirculatory alterations with reduced nutritive supply to the pancreas could be the cause of hyperamylasemia, which occurs in some patients receiving the vasoactive oxygen carrier diaspirin cross-linked hemoglobin (DCLHb) in clinical studies. Therefore, the effects of DCLHb on rat pancreas microcirculation were evaluated. Anesthetized Sprague-Dawley rats received one of the following treatments during baseline conditions (n = 7 rats/group): 10% hydroxyethyl starch (HAES) (0.4 ml/kg), DCLHb (400 mg/kg), or DCLHb (1,400 mg/kg). After 1 h of complete, reversible pancreatic ischemia, other animals received 10% HAES (0.4 ml/kg) or DCLHb (400 mg/kg) during the onset of reperfusion. The number of red blood cell-perfused capillaries (functional capillary density, FCD) and the level of leukocyte adherence in postcapillary venules in the pancreas were assessed by means of intravital microscopy during 2 h after treatment. In the nonischemic groups, FCD was 18% greater after DCLHb (1,400 mg/kg) than after 10% HAES treatment without any increase in leukocyte adherence. In the inschemia-reperfusion (I/R) 10% HAES group, FCD was significantly (P < 0.05) lowered, leukocyte adherence enhanced, and mean arterial pressure (MAP) reduced by 31% compared with nonischemic animals. DCLHb treatment in the I/R group resulted in a slight increase in FCD, a significant (P < 0.05) reduction of leukocyte adherence, and a complete restoration of MAP compared with the animals of the I/R control group. Thus our data provide no evidence for a detrimental effect on the pancreatic microcirculation or an enhanced risk of postischemic pancreatitis by DCLHb.