Apolipoprotein D expression in substantia nigra of Parkinson disease.

Apolipoprotein D (apo D), a lipocalin transporter of small hydrophobic molecules could play an important role in several neurodegenerative diseases. However, its role in those diseases remains unclear. Increments of apo D have been reported in relation with injury and degeneration in the nervous system. Recently increases of apo D level have been reported in schizophrenia, a neuropathologic disease where the oxidative stress and lipid abnormalities may be involved. Apo D could act as a sequestering molecule binding excess of arachidonic acid in cells. In order to determine the relationship between apo D expression and other neurodegenerative pathologies related to oxidative damage, we studied the presence of apo D in the substantia nigra of control and Parkinson disease (PD) subjects. We found dopaminergic neurons were not immunoreactive for apo D, control or PD subjects. However, surrounding glial cells showed immuno-staining for apo D and signal increases in PD cases. These findings support the role of apolipoprotein D in neuroprotection and the importance of glia in the amount of this protein in the central nervous system.