Neurotrophic factors: basis for their clinical application

Neurotrophic factors are molecules that regulate neuronal survival, nervous system plasticity and many other physiological functions of neuronal and glial cells, as well as some non-neuronal tissues. They have been involved in the etiopathogenesis of some neurodegenerative disorders, and some of them have been proposed as potential treatments for these diseases on the basis of in vitro experiments and animal models. The main neurotrophic factor families with potential therapeutic applications include the family of neurotrophins (NGF, BDNF or NT-3), GDNF and related neurotrophic factor, CNTF and the members of the IGF family. Some of these molecules have already been tested in clinical trials with contradictory results. One of the major challenges to their clinical use is the difficulty to deliver them into the central nervous system. Nevertheless, solid rational exists for the possible use of neurotrophic factors in the treatment of Alzheimer's and Parkinson's diseases, peripheral neuropathies or amyotrophic lateral sclerosis. This review compiles the essential aspects of neurotrophic factors and the current studies of their clinical relevance and therapeutic potentialities. Future directions for further research are also discussed.