26 research outputs found
CFU-S(11) activity does not localize solely with the aorta in the aorta-gonad-mesonephros region
The aorta-gonad-mesonephros (AGM) region is a potent hematopoietic site in
the midgestation mouse conceptus and first contains colony-forming
units-spleen day 11 (CFU-S(11)) at embryonic day 10 (E10). Because
CFU-S(11) activity is present in the AGM region before the onset of
hematopoietic stem cell (HSC) activity, CFU-S(11) activity in the complex
developing vascular and urogenital regions of the AGM was localized. From
E10 onward, CFU-S(11) activity is associated with the aortic vasculature,
and is found also in the urogenital ridges (UGRs). Together with data
obtained from organ explant cultures, in which up to a 16-fold increase in
CFU-S(11) activity was observed, it was determined that CFU-S(11) can be
increased autonomously both in vascular sites and in UGRs. Furthermore,
CFU-S(11) activity is present in vitelline and umbilical vessels. This,
together with the presence of CFU-S(11) in the UGRs 2 days before HSC
activity, suggests both temporally and spatially distinct emergent sources
of CFU-S(11). (Blood. 2000;96:2902-2904
Of lineage and legacy: The development of mammalian hematopoietic stem cells
The hematopoietic system is one of the first complex tissues to develop in the mammalian conceptus. Of particular interest in the field of developmental hematopoiesis is the origin of adult bone marrow hematopoietic stem cells. Tracing their origin is complicated because blood is a mobile tissue and because hematopoietic cells emerge from many embryonic sites. The origin of the adult mammalian blood system remains a topic of lively discussion and intense research. Interest is also focused on developmental signals that induce the adult hematopoietic stem cell program, as these may prove useful for generating and expanding these clinically important cell populations ex vivo. This review presents a historical overview of and the most recent data on the developmental origins of hematopoiesis