The blood stem cells that live in bone marrow are at the top of a complex family tree. Such stem cells split and divide down various pathways that ultimately produce red cells, white cells and platelets. These “daughter” cells must be produced at a rate of about one million per second to constantly replenish the body’s blood supply.
Researchers have long wondered what allows these stem cells to persist for decades, when their progeny last for days, weeks or months before they need to be replaced. Now, a study from the University of Pennsylvania has uncovered one of the mechanisms that allow these stem cells to keep dividing in perpetuity.
The researchers found that a form of the motor protein that allows muscles to contract helps these cells divide asymmetrically, so that one part remains a stem cell while the other becomes a daughter cell. Their findings could provide new insight into blood cancers, such as leukemia, and eventually lead to ways of growing transfusable blood cells in a lab.
More here Blood stem cell longevity explained.