Xu et al. [38] performed a highly interesting study using three doses of ATRA (low doses, 6–10.7 mg/kg/day; medium doses, 12.7–18.8 mg/kg/day; high doses, 20.1–27.4 mg/kg/day) in Alb/TGF-β1 transgenic mice (induces progressive renal fibrosis and retinoic acid deficiency in the kidneys), and reported that the low doses had a tendency to reduce the average urinary albumin excretion, as well as renal retinaldehyde dehydrogenase 2 (RALDH2; catalyzes the synthesis of RA from retinaldehyde), FN, COL-1A1, COL-1A2 and COL-4A1 compared with the control group (C57BL/6J × CBA F1 mice). This evidence concerns the gene ALB and renal fibrosis.