Erythropoiesis in vertebrates: from ontogeny to clinical relevance.

Erythropoiesis is a complex process that starts in the course of embryo formation and it is maintained throughout the life of an organism. During the fetal development, erythropoiesis arises from different body sites and erythroblast maturation occurs in the fetal liver. After birth, erythropoiesis and erythroblast maturation take place exclusively in the bone marrow, generating a lifetime reservoir of red blood cells (RBCs), which are responsible for transporting oxygen through the bloodstream to tissues and organs. Several transcription factors and cytokines, such as GATA-1, GATA-2, FOG-1 and erythropoietin (EPO), constitute an elaborated molecular network that regulates erythropoiesis as they are involved in the differentiation and maturation of RBCs. The profound understanding of erythropoiesis is fundamental to avoid, treat or even soften the effects of erythropoietic clinical disorders and may be useful to improve patients' well-being.