Phenotypic changes of HSCs by the expression of albumin and/or ALDH1A. HSCs-P1 were transfected with plasmids encoding albumin, ALDH1A1, and ALDH1A2, either individually or in combination, and incubated in the presence of all-trans retinoic acid (50 nM) for 18 h. Cells were analyzed by oil red O staining. Scale bar, 20 μm. 