Effect of controlled delivery of neurotrophin-3 from fibrin on spinal cord injury in a long term model

J Control Release. 2006 Nov 28;116(2):204-10. doi: 10.1016/j.jconrel.2006.07.005. Epub 2006 Jul 8.

Abstract

The goal of this work was to assess the effect of the controlled delivery of neurotrophin-3 (NT-3) from an affinity-based delivery system in fibrin scaffolds on regeneration following spinal cord injury (SCI). A heparin-based delivery system (HBDS) was used to immobilize NT-3 within fibrin scaffolds via non-covalent interactions. The fibrin scaffolds were implanted in lesions immediately after injury in an adult rat model of SCI (complete ablation of a 2 mm segment of the cord at T9). Delivery of NT-3 was controlled by an affinity-based delivery system that limits drug loss by diffusion and releases the drug via cell-mediated processes. Twelve weeks after injury and treatment, animals treated with fibrin scaffolds and NT-3, with or without the delivery system, did not show functional improvement over saline controls. Substantial cavitation at edges of the lesion was present, and while neuronal fibers were present inside the lesion, traced corticospinal and dorsal sensory tracts did not regenerate into the lesion. Therefore, while previous studies indicate that the controlled delivery of NT-3 from fibrin scaffolds may increase the short term regenerative response, the continued degeneration of the cord, indicative of the severity of the injury, limits the long term regeneration stimulated by this treatment. Chronic or repeated treatments or a less severe injury model may prove useful in assessing the utility of controlled delivery systems for the treatment of spinal cord injury.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Delayed-Action Preparations
  • Disease Models, Animal
  • Drug Carriers* / chemistry
  • Drug Carriers* / pharmacology
  • Female
  • Fibrin* / chemistry
  • Fibrin* / pharmacology
  • Heparin / chemistry
  • Immunohistochemistry
  • Motor Activity / drug effects
  • Nerve Regeneration / drug effects*
  • Neurons, Afferent / drug effects
  • Neurotrophin 3 / metabolism
  • Neurotrophin 3 / pharmacology*
  • Neurotrophin 3 / therapeutic use
  • Peptides / chemistry
  • Protein Binding
  • Pyramidal Tracts / drug effects
  • Pyramidal Tracts / physiopathology
  • Rats
  • Rats, Long-Evans
  • Recovery of Function / drug effects
  • Spinal Cord Injuries / drug therapy*
  • Spinal Cord Injuries / pathology
  • Spinal Cord Injuries / physiopathology
  • Spinal Nerves / drug effects*
  • Spinal Nerves / pathology
  • Spinal Nerves / physiopathology
  • Time Factors

Substances

  • Delayed-Action Preparations
  • Drug Carriers
  • Neurotrophin 3
  • Peptides
  • Fibrin
  • Heparin