[The involvement of apolipoprotein D in pathologies affecting the nervous system]

The apolipoprotein D (apo D), a glycoprotein belongs to lipocalin superfamily, is presented in the majority of corporal fluids as well as in a wide variety of different organs and tissues in mammals. As member of those proteins, apo D could act as a carrier of small hydrophobic molecules. Apo D shows affinity to different molecules like cholesterol, progesterone, bilirubin and arachidonic acid, but its physiological ligand is yet unknown. It has been suggest that its ligands and functions are different depending on the tissue or physiological conditions. In relation to the nervous system, apo D is synthesized usually by nervous cells but its levels increases after any type of stress or injury of the nervous tissue. The increment in apo D expression has been demonstrated in many encephalopathies, therefore it could be an important neuropathological marker.

Even though its particular role in nervous system has not been well established, this apolipoprotein could represent a neuroprotective protein taking part in lipid transport during homeostasis and repair processes in normal and pathological conditions.