• Open Access

Concise Review: Early Embryonic Erythropoiesis: Not so Primitive After All§

Authors

  • Margaret H. Baron

    Corresponding author
    1. Department of MedicineMount Sinai School of Medicine, New York, New York, USA
    2. Department of Developmental and Regenerative BiologyMount Sinai School of Medicine, New York, New York, USA
    3. Department of Oncological SciencesMount Sinai School of Medicine, New York, New York, USA
    4. The Tisch Cancer InstituteMount Sinai School of Medicine, New York, New York, USA
    5. The Black Family Stem Cell InstituteMount Sinai School of Medicine, New York, New York, USA
    6. The Graduate School of Biomedical Sciences, Mount Sinai School of Medicine, New York, New York, USA
    • Mount Sinai School of Medicine, 1468 Madison Avenue Box 1079, Annenberg 24-04E, New York, New York 10029-6574, USA
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  • Author contributions: M.H.B.: wrote the paper.

  • Disclosure of potential conflicts of interest is found at the end of this article.

  • §

    First published online in STEM CELLSEXPRESS January 29, 2013.

Abstract

In the developing embryo, hematopoiesis begins with the formation of primitive erythroid cells (EryP), a distinct and transient red blood cell lineage. EryP play a vital role in oxygen delivery and in generating shear forces necessary for normal vascular development. Progenitors for EryP arise as a cohort within the blood islands of the mammalian yolk sac at the end of gastrulation. As a strong heartbeat is established, nucleated erythroblasts begin to circulate and to mature in a stepwise, nearly synchronous manner. Until relatively recently, these cells were thought to be “primitive” in that they seemed to more closely resemble the nucleated erythroid cells of lower vertebrates than the enucleated erythrocytes of mammals. It is now known that mammalian EryP do enucleate, but not until several days after entering the bloodstream. I will summarize the common and distinguishing characteristics of primitive versus definitive (adult-type) erythroid cells, review the development of EryP from the emergence of their progenitors through maturation and enucleation, and discuss pluripotent stem cells as models for erythropoiesis. Erythroid differentiation of both mouse and human pluripotent stem cells in vitro has thus far reproduced early but not late red blood cell ontogeny. Therefore, a deeper understanding of cellular and molecular mechanisms underlying the differences and similarities between the embryonic and adult erythroid lineages will be critical to improving methods for production of red blood cells for use in the clinic. STEM CELLS 2013;31:849–856

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