RDH10 and heart failure: We measured the levels of cardiac 4-HNE, MDA, iron, and non-heme iron in RDH10-cKO mice and found increased 4-HNE and MDA levels (Fig. 7a–d), which only provided evidence of lipid peroxidation rather than ferroptosis; thus, we further treated RDH10-cKO mice with the ferroptosis inhibitor ferrostatin-1 (Fer-1) to confirm the presence of ferroptosis and found that Fer-1 rescued heart failure and inhibited cardiac 4-HNE accumulation in RDH10-cKO mice (Fig. 7e–h), which suggested that ferroptosis, mainly caused by lipid peroxidation, is involved in myocardial injury in RDH10-cKO mice.