Peripheral nerve grafts to the frog optic tectum: A morphological study of foreign axon regeneration in the central nervous system

1985 ◽  
Vol 235 (3) ◽  
pp. 395-415 ◽  
Author(s):  
Elliot I. Kaplan ◽  
Carmine D. Clemente
2002 ◽  
Vol 96 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Allan D. O. Levi ◽  
Hector Dancausse ◽  
Xiuming Li ◽  
Suzanne Duncan ◽  
Laura Horkey ◽  
...  

Object. Partial restoration of hindlimb function in adult rats following spinal cord injury (SCI) has been demonstrated using a variety of transplantation techniques. The purpose of the present study was twofold: 1) to determine whether strategies designed to promote regeneration in the rat can yield similar results in the primate; and 2) to establish whether central nervous system (CNS) regeneration will influence voluntary grasping and locomotor function in the nonhuman primate. Methods. Ten cynomologus monkeys underwent T-11 laminectomy and resection of a 1-cm length of hemispinal cord. Five monkeys received six intercostal nerve autografts and fibrin glue containing acidic fibroblast growth factor (2.1 µg/ml) whereas controls underwent the identical laminectomy procedure but did not receive the nerve grafts. At 4 months postgrafting, the spinal cord—graft site was sectioned and immunostained for peripheral myelin proteins, biotinylated dextran amine, and tyrosine hydroxylase, whereas the midpoint of the graft was analyzed histologically for the total number of myelinated axons within and around the grafts. The animals underwent pre- and postoperative testing for changes in voluntary hindlimb grasping and gait. Conclusions. 1) A reproducible model of SCI in the primate was developed. 2) Spontaneous recovery of the ipsilateral hindlimb function occurred in both graft- and nongraft—treated monkeys over time without evidence of recovering the ability for voluntary tasks. 3) Regeneration of the CNS from proximal spinal axons into the peripheral nerve grafts was observed; however, the grafts did not promote regeneration beyond the lesion site. 4) The grafts significantly enhanced (p < 0.0001) the regeneration of myelinated axons into the region of the hemisected spinal cord compared with the nongrafted animals.


2011 ◽  
Vol 21 (22) ◽  
pp. 4232-4242 ◽  
Author(s):  
Corinne R. Wittmer ◽  
Thomas Claudepierre ◽  
Michael Reber ◽  
Peter Wiedemann ◽  
Jonathan A. Garlick ◽  
...  

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Linqing Miao ◽  
Liu Yang ◽  
Haoliang Huang ◽  
Feisi Liang ◽  
Chen Ling ◽  
...  

Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration.


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