Hematopoietic stem cells engraft much more efficiently than previously thought. In the July issue of Nature Immunology, Canadian researchers report that every stem cell introduced by transplantation successfully engrafts in the bone marrow. However, only a minority of these established stem cells contribute to long-term hematopoiesis.
Iscove and colleagues show nearly every irradiated mouse that received only one stem cell, on average, can generate blood cells of donor origin within the first 4-8 weeks, signaling successful engraftment. But when these mice were analyzed 32 weeks later, only 25% generated donor blood cells, suggesting that a loss of stem cell self-renewal occurred. Thus, long-term hematopoietic stem cell potential does not appear to be limited by their engraftment success, rather it reflects the variable ability to self-renew once established in the bone marrow.
Norman N. Iscove
The Ontario Cancer Institute
University of Toronto
Tel: +1 416 946 4501 ext 4987
Also available online.
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza