GDNF and Alzheimer disease: Accordingly, administration of adipose tissue (AT)-MSC-overexpressing GDNF into 6-OHDA mouse model of PD [67], BM-MSC-overexpressing VEGF into APP/PS1 mouse model of AD [68], BM-MSC-overexpressing BDNF into an Aβ rat model of AD [69], MPTP monkeys model of PD [70], and YAC128 mice model of HD [71], and finally injection of UC-MSC-overexpressing BDNF into SOD1G93A mouse model of ALS [72] resulted in promising outcomes in vivo.