Int. J. Dev. Biol. 54: 1089 - 1098 (2010)
doi: 10.1387/ijdb.103070cg
© UBC Press

Hematopoietic stem cell development in the placenta

Christos Gekas, Katrin E. Rhodes, Ben Van Handel, Akanksha Chhabra, Masaya Ueno and Hanna K.A. Mikkola*

University of California Los Angeles, Los Angeles, CA, USA

ABSTRACT The placenta is a highly vascularized organ that mediates fetal-maternal exchange during pregnancy and is thereby vital for the survival and growth of the developing embryo. In addition to having this well-established role in supporting pregnancy, the placenta was recently shown to function as a hematopoietic organ. The placenta is unique among other fetal hematopoietic organs, as it is capable of both generating multipotential hematopoietic cells de novo and establishing a major hematopoietic stem cell (HSC) pool in the conceptus, while protecting HSCs from premature differentiation. The mouse placenta contains two distinct vascular regions that support hematopoiesis: the large vessels in the chorionic plate where HSCs/progenitors are thought to emerge and the labyrinth vasculature where nascent HSCs/progenitors may colonize for expansion and possible functional maturation. Defining how this cytokine- and growth factor rich organ supports HSC generation, maturation and expansion may ultimately help to establish culture protocols for HSC expansion or de novo generation from pluripotent cells.


placenta, hematopoietic stem cell, niche, allantois, hemogenic endothelium

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