Iron-loaded deferiprone can support full hemoglobinization of cultured red blood cells in the absence of transferrin

Iron is an essential nutrient in mammalian cell cultures, conventionally supplemented as iron-loaded transferrin (holotransferrin). The high cost of human transferrin represents a challenge for the large scale production of cell therapies, such as cultured red blood cells. We evaluated the use of deferiprone, a cell membrane-permeable drug for iron chelation therapy, as an iron carrier for erythroid cultures. Iron-loaded deferiprone (Def3·Fe3+) at a concentration of 52μmol/L could fully replace holotransferrin during erythroblast differentiation into reticulocytes, the erythroid differentiation stage with maximal iron requirements. Reticulocytes cultured in presence of Def3·Fe3+ or holotransferrin (1000μg/mL) were similar with respect to expression of cell-surface markers CD235a and CD49d, hemoglobin content, and oxygen association/dissociation. Def3·Fe3+ also supported expansion of the erythroid compartment in vitro, except for the first stage when hematopoietic stem cells committed to erythroblasts, in which a reduced erythroblasts yield was observed. This suggests that erythroblasts acquired the potential to process Def3·Fe3+ as iron source for biosynthesis pathways. Replacement of holotransferrin by Def3·Fe3+ was also successful in cultures of six myeloid cell lines (MOLM13, NB4, EOL1, K562, HL60, ML2). These results suggest that iron-loaded deferiprone can partially replace holotransferrin in chemically defined medium formulations for the production of cultured reticulocytes and proliferation of selected myeloid cell lines. This would lead to a significant decrease in medium cost that would improve the economic perspectives of the large scale production of red blood cells for transfusion purposes.