A non-invasive transport system for GDNF across the blood-brain barrier.

Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophin which supports midbrain dopaminergic neurons and spinal cord motorneurons. GDNF has been proposed as a possible therapeutic agent for Parkinson's disease, spinal cord injury or motorneuron degenerative disorders. Administration of GDNF is complicated by its poor penetration across the blood-brain barrier (BBB). Central nervous system capillaries are uniquely enriched in transferrin receptors and antibodies to these receptors (OX-26) have been proposed as potential carriers to transport large molecules across the BBB. Intravenous administration of an OX-26-GDNF conjugate enhanced survival of spinal cord motorneurons in intraocular transplants, which possess an organotypic BBB. This suggests that the OX-26-GDNF conjugate could be utilized for non-invasive treatment of neurodegenerative diseases of the spinal cord or midbrain dopaminergic neurons.