Young and aged HPCs do not differ with respect to their ability to cross an endothelial cell layer. (A) Experimental setup for the transwell-migration assay. (B) Percentage of CFCs from mobilized young (2-3 months) and aged (24 months) mice migrating in 18 hours into the lower well of the transwell. n = 3. Values shown are mean ± 1 SEM. LDBM indicates low-density BM cells.