Iron and erythropoiesis: A mutual alliance.

The large amount of iron required for hemoglobin synthesis keeps iron homeostasis and erythropoiesis inter-connected, both iron levels being affected by increased erythropoiesis, and erythropoiesis regulated by serum iron. The connection between these 2 processes is maintained even when erythropoiesis is ineffective. In the last years great advances in the understanding of the mechanisms of this crosstalk have been achieved thanks to the discovery of 2 essential players: hepcidin, the master regulator of iron homeostasis, and erythroferrone, the long sought erythroid regulator. In addition, how circulating transferrin-bound iron contributes to the crosstalk between the 2 systems has started to be unraveled.