Repairing the parkinsonian brain with neurotrophic factors.

No therapy exists to slow down or prevent Parkinson's disease (PD), a debilitating neurodegenerative disorder. Neurotrophic factors (NTFs) emerged as promising disease-modifying agents in PD and are currently under clinical development. We argue that efforts in three research areas must converge to harness the full therapeutic power of NTFs. First, the physiological roles of NTFs in aging dopaminergic neurons must be comprehensively understood. Second, the mechanisms underlying the neuroprotective, neurorestorative and stimulatory effects of NTFs on diseased neurons need to be defined. Third, improved brain delivery of NTFs and new ways to stimulate NTF signaling are required to achieve clinical benefits. In this review, we discuss progress in these areas and highlight emerging concepts in NTF biology and therapy.