The use of neurotrophic factors to treat spinal cord injury: Advantages and disadvantages of different delivery methods

Neurotrophic factors are well known for their use in stimulating regenerati on in the adult central nervous system. However, delivery of neurotrophic f actors to e.g. the injured spinal cord is notoriously difficult, since thes e proteins do not cross the blood brain barrier. Several strategies have be en developed that now allow for convenient delivery of neurotrophic factors to injured neurons. These include: 1. methods to deliver the protein itsel f, 2. the use of transplanted cells genetically engineered to secrete neuro trophic factors and 3. direct transfer of neurotrophic factor genes using v iral vectors. In this review, the advantages and disadvantages of these del ivery methods that have been applied in spinal cord injury models will be d iscussed.