Degeneration and regeneration of the nervous system

This study was performed to determine whether vein grafts might serve as a conduit for nerve regeneration. A 1 cm segment of sciatic nerve was removed bilaterally in 12 Sprague-Dawley rats. On one side the gap was not repaired, and on the other side a segment of femoral vein was used to bridge the nerve gap. Nerve conduction studies and necropsies were performed at intervals. Reconstitution of nerve trunk continuity and healing of plantar ulcers occurred only in the vein-grafted side. Histologic examination revealed orderly growth of nerve fibers within the lumen of the vein grafts as early as 1 month after repair. Most regenerating nerve fibers passed through the proximal junction in an orderly pattern and reached the distal stumps within 2 months after repair. Results of nerve conduction study at 4 months after operation demonstrated restoration of conduction through the vein-grafted sciatic nerves with muscle reinnervation. Nearly normal muscle fibers in the gastrocnemius on the repaired side were confirmed at necropsy. This study demonstrated that autogenous vein grafts can serve as a conduit for nerve regeneration in rodents.

Autogenous vein graft as a conduit for nerve regeneration

Objective: To investigate the effect of brain-derived neurotrophic factor (BDNF) and collagen tubulization (CT) on the regeneration of transected peripheral nerves. Methods and Design: The left sciatic nerve of 40 Sprague-Dawley rats was transected then repaired using one of four techniques: epineurial coaptation, CT, CT with BDNF delivered by an osmotic pump to the repair site, or CT with BDNF covalently cross-linked to the collagen matrix (CT/linked-BDNF). Sciatic functional indices were measured preoperatively and then postoperatively at 10-day intervals for 90 days. Segments of the sciatic nerves proximal and distal to the repair site were harvested at 90 days for histologic and morphometric evaluation. Results: Animals repaired by CT/linked-BDNF (n=10) demonstrated the most favorable functional recovery of all groups, with statistically significant differences seen compared with animals repaired by CT (n=10, P=.05) and epineurial coaptation (n=9, P<.001). Animals repaired by CT with BDNF delivered by an osmotic pump (n=8) and CT also showed statistically superior functional recovery compared with those repaired by epineurial coaptation (P=.005 and P=.02, respectively). Nerves repaired by CT/linked-BDNF had the largest mean axon diameters proximal and distal to the repair site. Conclusions: Brain-derived neurotrophic factor and CT improve the rate and the degree to which recovery of sciatic function occurs after nerve transection and repair. Animals repaired by CT/BDNF-linked demonstrated the most favorable functional recovery of all groups. Animals whose repair technique included BDNF had the largest mean axon diameters of all groups.

Brain-derived neurotrophic factor and collagen tubulization enhance functional recovery after peripheral nerve transection and repair

The central nervous system (CNS) is the most important section of the nervous system as it regulates the function of various organs. Injury to the CNS causes impairment of neurological functions in corresponding sites and further leads to long-term patient disability. CNS regeneration is difficult because of its poor response to treatment and, to date, no effective therapies have been found to rectify CNS injuries. Biomaterial scaffolds have been applied with promising results in regeneration medicine. They also show great potential in CNS regeneration for tissue repair and functional recovery. Biomaterial scaffolds are applied in CNS regeneration predominantly as hydrogels and biodegradable scaffolds. They can act as cellular supportive scaffolds to facilitate cell infiltration and proliferation. They can also be combined with cell therapy to repair CNS injury. This review discusses the categories and progression of the biomaterial scaffolds that are applied in CNS regeneration.

/pdf/biomaterial-scaffolds-in-regenerative-therapy-of-the-central-26pkhlj39k.pdf

Biomaterial Scaffolds in Regenerative Therapy of the Central Nervous System

Matrices, scaffolds & carriers for cell delivery in nerve regeneration.

Treatment of spinal cord injury has always been a challenge for clinical practitioners and scientists. The development in stem cell based therapies has brought new hopes to patients with spinal cord injuries. In the last a few decades, a variety of stem cells have been used to treat spinal cord injury in animal experiments and some clinical trials. However, there are many technical and ethical challenges to overcome before this novel therapeutic method can be widely applied in clinical practice. With further research in pluripotent stem cells and combined application of genetic and tissue engineering techniques, stem cell based therapies are bond to play increasingly important role in the management of spinal cord injuries.

Stem cell based therapies for spinal cord injury.

The theory of chemotaxis has been widely accepted, but its mechanisms are disputed. Chemotactic growth of peripheral nerves may be tissue, topographic and end-organ specific. Recent studies indicated that peripheral nerve regeneration lacks topographic specificity, but whether it has end-organ specificity is disputed. Chemotaxis in nerve regeneration is affected by the distance between stumps, volume, and neurotrophic support, as well as the structure of distal nerve stumps. It can be applied to achieve precise repair of nerves and complete recovery of end organ function. Small gap sleeve bridging technique, which is based on this theory shows promising effects but it is still challenging to find the perfect combination of nerve conduits, cells and neurotrophic factors to put it intoits best use. In this paper, we made a comprehensive review of mechanisms, effect factors and applications of chemotaxis.

Advances in experimental and clinical studies of chemotaxis.

Femoral nerve regeneration and its accuracy under different injury mechanisms

Combined use of Y-tube conduits with human umbilical cord stem cells for repairing nerve bifurcation defects.

http://or.nsfc.gov.cn/bitstream/00001903-5/581964/1/1000013474277.pdf

Jiang Peng

Papers

Stem cell based therapies for spinal cord injury.

Advances in experimental and clinical studies of chemotaxis.

Femoral nerve regeneration and its accuracy under different injury mechanisms

Combined use of Y-tube conduits with human umbilical cord stem cells for repairing nerve bifurcation defects.

Combination of Acellular Nerve Allograft and Human Umbilical Wharton Jell Stem Cells to Bridge Rat Femoral Nerve Defect