title: Complement activation and the toxicity of stroma-free hemoglobin solutions in primates.
abstract: The toxicity of hemoglobin solutions was studied in the context of their ability to activate serum complement (C). Three bovine polymerized hemoglobin solutions (BPHSs) with different degrees of purity were used for experiments in vitro and in vivo. BPHS-1 contained bacterial endotoxins (E) (5 EU/ml) and stromal phospholipids (PLs) (1.2 mg/dl), BPHS-2 contained only PLs (2.0 mg/dl), while BPHS-3 was completely free of both contaminants. C-activation was studied by the direct measurement of C3a, C4a, and C5a des Arg fragments, using commercially available RIA kits. During 1 hour of incubation with fresh monkey plasma, BPHS-1 and -2 activated both pathways of C, while BPHS-3 caused no activation of any factor. In vivo, Hb solutions were used to replace one-third of blood volume in three groups of six Coebus monkeys each, while fresh homologous plasma was used in a control group of four animals. Impure solutions activated the alternative pathway of C and caused significant reactions of the circulating blood (thrombocytopenia, leukopenia, and disseminated intravascular coagulation) associated with multiorgan dysfunction (cardiac arrhythmias, hypoxemia, reduction of renal clearance of endogenous creatinine, and elevation of liver enzyme SGPT). The pure solution neither activated C nor caused any reaction in the circulating blood. However, it caused a moderate degree of direct tissue injury, evidenced by transient reduction of creatinine clearance and elevation of SGPT. These observations suggest that impure and pure Hb solutions carry separate mechanisms of toxicity. Complement, activated by toxic impurities, plays an active role in the toxicity of impure solutions. C-activation in vitro could be used as a screening test of biocompatibility.
authors.affiliation: Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX 79430.
authors.forename: M
authors.initials: M
authors.lastname: Feola
authors.forename: J
authors.initials: J
authors.lastname: Simoni
authors.forename: M
authors.initials: M
authors.lastname: Dobke
authors.forename: P C
authors.initials: PC
authors.lastname: Canizaro
mesh_terms: D000818:Animals; D001802:Blood Substitutes; D002417:Cattle; D002428:Cebus; D003167:Complement Activation; D003176:Complement C3 / Q000031:analogs & derivatives / Q000378:metabolism; D015926:Complement C3a / Q000031:analogs & derivatives*; D003181:Complement C4 / Q000031:analogs & derivatives / Q000378:metabolism; D015934:Complement C4a; D003182:Complement C5 / Q000031:analogs & derivatives / Q000378:metabolism; D015937:Complement C5a, des-Arginine; D004731:Endotoxins / Q000494:pharmacology; D006454:Hemoglobins / Q000502:physiology*; D007700:Kinetics; D008297:Male; D010743:Phospholipids / Q000494:pharmacology; D012996:Solutions
chemical_list: D001802:Blood Substitutes; D003176:Complement C3; D003181:Complement C4; D003182:Complement C5; D015937:Complement C5a, des-Arginine; D004731:Endotoxins; D006454:Hemoglobins; D010743:Phospholipids; D012996:Solutions; C044541:complement C3a, des-Arg-(77)-; C051066:complement C4a, des-Arg; C037158:polyhemoglobin; D015926:Complement C3a; D015934:Complement C4a