In vivo implantation of NDNF‐overexpressing old hADSCs improved cardiac function after MI. A, Representative M‐mode echocardiographic images taken before (baseline), and 7 and 28 days after myocardial infarction (MI) in mice that received implantation of control medium (Medium), empty vector‐transduced old human adipose‐derived stem cells (hADSCs, Old), neuron‐derived neurotrophic factor (NDNF)‐transduced old hADSCs (Old + NDNF) and untransduced young hADSCs (Young). The left ventricular fractional shortening (B, FS %), ejection fraction (C, EF %), left ventricular internal dimension‐diastole (D, LVIDd) and left ventricular internal dimension in systole (E, LVIDs ), of mice before and 7, 14, 21, and 28 days after MI, reflecting the changes in cardiac function of mice. FS and EF were significantly higher whereas LVIDs and LVIDd were significantly lower in the Young and Old + NDNF compared to the Old and Medium groups at 28 days after MI. n = 7/group, *P < 0.05,**P < 0.01