At the brain level, lactoferrin (Lf) is a ligand that favors the absorption of NPs in the BBB since there is an increase in the expression of lactoferrin receptors (LfRs) in the substantia nigra and striatal dopaminergic neurons, as well as in the endothelial cells of the BBB of PD patients [115, 116]. This evidence concerns the gene LTF and Parkinson disease.