To further validate the role of RDH10 and cardiac retinol metabolism in DCM, we overexpressed RDH10 in the hearts of db/db mice via adeno-associated virus 9 (AAV9)-RDH10 injection at week 8 after experimental baseline (Fig. 5a) and verified that the expression of cardiac RDH10 of these mice restored to a level comparable to that of db/m mice after 5 weeks (Supplementary Fig. 5a and b). This evidence concerns the gene RDH10 and familial dilated cardiomyopathy.