Culture of total human cord blood cells in the presence of Angptl5 stimulates ex vivo expansion of HSCs. (A) Culture of 2.5 × 10⁷ total human cord blood cells was initiated in serum-free STIF medium or the same STIF medium containing 100 ng/mL Angptl5, and total cell numbers were counted at the indicated time. (B) Amount of human chimerism in the bone marrow of NOD/SCID mice that received a transplant of 10⁶ uncultured human mononuclear cord blood cells or the cultured progeny of 10⁶ initial human cord blood cells. Each symbol represents the engraftment of a single mouse that underwent transplantation assayed at 2 months after transplantation. *Significantly different from lane 1 value. Student t test, P < .001.