FGF21 and Parkinson disease: In PD cell models, conditioned medium from FGF21-overexpressing MSCs or recombinant FGF21 reversed dopaminergic neuron death, reduced mitochondrial ROS, and enhanced the levels of phospho-Akt, mature BDNF, and Bcl-2, underscoring the therapeutic potential of FGF21-based MSC treatments for PD [133].