PVR and Parkinson disease: To this end, we also took advantage of transgenic BATGAL mice expressing nuclear beta‐galactosidase under the control of the β‐catenin‐activated transgene (BAT) promoter (Maretto et al., 2003), together with both in vivo experimental PD young and older mice models, coupled to ex vivo/in vitro cell cultures of midbrain‐Aq‐PVR‐NSCs (mNSCs).