Fig. 1

Aging-related changes in pHSCs and flu⁺ HSCs. a Compared to young mice, LSK cells are increased by 1.9-fold in BM of old mouse pHSCs. However, HSCs and flu⁺HSCs in BM of old mice are expanded by 10–17-fold and 20–50-fold, respectively, owing to the dramatically increased ratios of pHSCs/LSK and flu⁺HSCs/pHSCs. b The reduction in ratios of pHSCs/LSK and flu⁺HSCs/pHSCs in old mice might be due to the reduced production of MPPs and/or increased production of MKPs or other committed progenitors which bypass the MPP stage