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Article first published online: 24 APR 2013
Copyright © 2013 AlphaMed Press
Volume 31, Issue 5, pages 849–856, May 2013
How to Cite
Baron, M. H. (2013), Concise Review: Early Embryonic Erythropoiesis: Not so Primitive After All. STEM CELLS, 31: 849–856. doi: 10.1002/stem.1342
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.
- Issue published online: 24 APR 2013
- Article first published online: 24 APR 2013
- Accepted manuscript online: 29 JAN 2013 11:02PM EST
- Manuscript Accepted: 27 DEC 2012
- Manuscript Received: 23 AUG 2012
- National Institutes of Health. Grant Numbers: RO1 HL62248, DK52191, EB02209
- Roche Foundation for Anemia Research. Grant Number: 9699367999, cycle X
- New York State Department of Health. Grant Number: NYSTEM Grant N08G-024
- Primitive erythropoiesis;
- Transgenic mice;
- Mammalian embryo;
- Erythroid progenitors;
- Erythroid differentiation;
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