title: Hemolysis in stored red blood cell concentrates: modulation by haptoglobin or ulinastatin, a protease inhibitor.
abstract: OBJECTIVE
  Polymorphonuclear leukocyte elastase may injure various tissues. The release of polymorphonuclear leukocyte elastase induced by various stimuli was reported to be inhibited by a protease inhibitor, ulinastatin. In stored blood preparations, polymorphonuclear leukocyte elastase increases depending on the storage days as hemolysis increases. We hypothesized that polymorphonuclear leukocyte elastase might be one of the factors inducing hemolysis in stored blood. Haptoglobin binds to free hemoglobin to reduce hemolysis. The purpose of the study was to investigate the effects of ulinastatin on hemolysis in blood preparations in comparison with haptoglobin.
  
  
  METHODS
  In vitro study.
  
  
  METHODS
  Laboratory in a university hospital.
  
  
  METHODS
  Nine 2-day-old packs of red blood cell concentrates (CRC) in 400 mL each of mannitol, adenine, glucose, phosphate, and citrate (MAP) (MAP-CRC) from the Japan Red Cross Society.
  
  
  METHODS
  Each MAP-CRC was divided into three different packs of equal amount and was treated with 10 mL of saline (control group), 200 units of haptoglobin, or 50,000 units of ulinastatin. They were stored at 4 degrees C.
  
  
  RESULTS
  Supernatant concentrations of total and free hemoglobin, total haptoglobin, polymorphonuclear leukocyte elastase, and potassium were measured for 25 days. Free haptoglobin concentration was calculated. Total and free hemoglobin concentrations increased significantly depending on the storage days in the control group, whereas haptoglobin and ulinastatin groups showed no increase. Total and free haptoglobin concentrations were significantly higher in the haptoglobin group than in the other two groups. Free haptoglobin concentrations were 0 after 5 days of storage in the control and ulinastatin groups. Polymorphonuclear leukocyte elastase concentrations increased with the increase in storage days without any differences among the three groups. Potassium concentration increased according to the storage and showed the highest value in the control group.
  
  
  CONCLUSIONS
  Adding haptoglobin or ulinastatin to MAP-CRC was useful to suppress hemolysis during storage of the preparation. The polymorphonuclear leukocyte elastase might not be involved in the mechanisms of hemolysis in MAP-CRC stored for 25 days.
authors.affiliation: Department of Surgical Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. nishiyam@ims.u-tokyo.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Nishiyama
authors.forename: K
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D001771:Blood Banks; D001803:Blood Transfusion; D004912:Erythrocytes / Q000502:physiology*; D006023:Glycoproteins / Q000494:pharmacology*; D006242:Haptoglobins / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D011480:Protease Inhibitors / Q000494:pharmacology*; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity
chemical_list: D006023:Glycoproteins; D006242:Haptoglobins; D011480:Protease Inhibitors; C028665:urinastatin