BMS493 is an inverse pan-retinoic acid receptor (RAR) agonist. BMS493 increases nuclear corepressor interaction with RARs. BMS493 also could prevent retinoic acid-induced differentiation^[1][2]. In Vitro: BMS493 (100 nM; 6 days; ALDHhi UCB cells) treatment shows a twofold increase in the number of ALDHhi cells available for transplantation compared with untreated controls. Newly expanded ALDHhi cells shows increased numbers of CD34 and CD133-positive cells, as well as a reduction in CD38 expression, a marker of hematopoietic cell differentiation^[1]. In Vivo: Intrapancreatic transplantation of cell progeny after expansion of ALDHhi cells with or without BMS493 shows no reduction of hyperglycemia in Streptozotocin-treated NOD/SCID mice. Thus, Umbilical cord blood (UCB)-derived ALDHhi cells effectively lost islet regenerative capacity during ex vivo expansion^[1].