Iron-chelator complexes as iron sources for early developing human erythroid precursors.

Developing erythroid cells are dependent on transferrin (Tf) to acquire iron in amounts sufficient for hemoglobin production. Previously, we showed that although these cells cannot grow in culture in the absence of Tf, ferritin (Ft) can substitute Tf to some extent and support the development of hemoglobin-containing cells. In the current study, we investigated the ability of various iron sources to replace Tf in cultures of normal human erythroid precursors.

Macrophages promote development of human erythroid precursors in transferrin-free culture medium.

Iron is mandatory for cell growth and development. Erythroid precursors need iron to a greater degree for hemoglobinization. Culturing erythroid precursors under serum and transferrin-free conditions resulted in their death, whereas under the same conditions, but in the presence of macrophages erythroid cell growth and development was evident as measured by hemoglobin (Hb)-specific cytochemical staining, flow cytometric immuno-staining of glycophorin A and Hb quantitation by a spectrophotometric method as well as by high performance liquid chromatography.

Developing human erythroid cells grown in transferrin-free medium utilize iron originating from extracellular ferritin.

In addition to transferrin, ferritin can also function as a source of iron for heme synthesis (Gelvin D, et al. Blood 1996;88:3200-3207; Meyron-Holtz EG, et al. Blood 1999;94:3205-3211).