Adult and fetal methemoglobin interaction with liposomes

Objective: Hemoglobin (Hb) solutions are used in clinical practice and efforts are underway to study methods and techniques of their storage. As Hb solutions are stored, oxygen-intolerant methemoglobin (metHb) is formed. Increased metHb content in Hb solutions adversely affects the potential for their use. It is of particular interest for neonatology as increased metHb content is observed in healthy neonates. To simulate the processes taking place in metHb-containing red blood cells we researched the adult (A) and fetal (F) metHb interaction with liposomes. Methods: We obtained metHb А and F by oxidation of Hb А and F, respectively, with potassium hexacyanoferrate(ІІІ) excess and subsequent dialysis. Hb A was isolated from donors’ and Hb F from umbilical blood. Egg phosphatidylcholine and cardiolipin from bovine heart were used. Liposomes were formed in the 4:1 phosphatidylcholine-cardiolipin weight ratio. Protein-lipid complexes were formed at 20�С. The kinetics of metHb A and F interaction with liposomes was studied by recording the changes of optical density of protein-lipid complexes in the Soret band maximum. Results: The kinetics of metHb A and F interaction with liposomes showed that a decrease of the protein optical density in the Soret band for metHb F was more apparent than for metHb A. Conclusions: As far as metHb induces lipid peroxidation in model membranes, it is fair to assume that this process is more intensive in case of metHb F-liposomes interaction than in case of metHb A-liposomes interaction. Probably, metHb F is less resistant to hydroperoxides than metHb A.