[Translational research for artificial red blood cells (hemoglobin vesicles)]

The blood supply system for transfusions in Japan functions well. However, in cases of sudden hemorrhagic shock, the swift supply of red blood cell (RBC) product might be difficult, particularly when medical care is required in remote regions and in obstetric medicine, where there is always a risk of hemorrhage. Blood pressure maintenance by infusion of volume expanders, such as crystalloids or colloids, may be insufficient to preserve the function of vital organs because they do not contain any oxygen-carrying molecules. If artificial RBCs were at hand, they could be used as a blood substitute until blood products are received from blood banks. This would save patients without degrading their quality of life. In the 1990s, we developed an artificial RBC in the form of a hemoglobin vesicle (Hb-V). Hb-V is a liposomal microparticle that encloses oxygen-carrying human Hb molecules. Different from RBCs, it has no blood type and is stable at room temperature, ensuring a long shelf-life. Its excellent biocompatibility and oxygen-carrying capacity have been proven in a number of animal experiments, and its production technique has also been established. Therefore, translational research is being designed with the aid of the Japan Agency of Medical Research and Development.