A Study and Follow-up (1999–2009) of Human Fetal Neuronal Tissue Transplants at a Heterotopic Site Outside the Brain in Cases of Advanced Idiopathic Parkinsonism

Abstract

During brain development, one of the most important structures is the subventricular zone (SVZ) from which most neurons are generated. In adulthood, the SVZ maintains a pool of progenitor cells that continuously replace neurons in the olfactory bulb. Neurodegenerative diseases induce a substantial upregulation or downregulation of SVZ progenitor cell proliferation, depending on the type of disorder. Far from being a dormant layer, the SVZ responds to neurodegenerative disease in a way that makes it a potential target for therapeutic intervention.

Patients with Parkinson’s disease experience tremors, slurred speed, and slowness of movement that eventually progresses to total paralysis. In this progressive, debilitating illness, the cells in a small part of the brain called the substantia nigra are destroyed, depriving the striatum (the part of the brain that controls movement) of a critical molecule called dopamine. Despite devastating loss of motor control, mental faculties in Parkinson’s patients remain intact, and while the disease is in itself not fatal, patients often succumb to complications such as injuries from falls or pneumonia. Parkinson’s disease (PD) is also an intractable degenerative neurological disorder that affects nerve cells in the part of the brain controlling muscle movement.