biostudies-literatureKadoya KInternational Spinal Research TrustDr. Miriam and Sheldon G. Adelson Medical Research FoundationBernard and Anne Spitzer Charitable TrustNINDS NIH HHSNational Institutes of HealthU.S. Department of Veterans Affairs165-72https://www.ebi.ac.uk/biostudies/studies/S-EPMC2773653biostudies-literatureUnknown64(2)Despite advances in promoting axonal regeneration after acute spinal cord injury (SCI), elicitation of bridging axon regeneration after chronic SCI remains a formidable challenge. We report that combinatorial therapies administered 6 weeks, and as long as 15 months, after SCI promote axonal regeneration into and beyond a midcervical lesion site. Provision of peripheral nerve conditioning lesions, grafts of marrow stromal cells, and establishment of NT-3 gradients supports bridging regeneration. Controls receiving partial components of the full combination fail to exhibit bridging. Notably, intraneuronal molecular mechanisms recruited by delayed therapies mirror those of acute injury, including activation of transcriptional activators and regeneration-associated genes. Collectively, these fNeuronCombined intrinsic and extrinsic neuronal mechanisms facilitate bridging axonal regeneration one year after spinal cord injury.PMC2773653F31 NS009881NS054883R01 NS054883R01 NS049881R01 NS09881Tuszynski MHBlesch AKadoya KGeschwind DTsukada SLu PCoppola GFilbin MTfalseCombined intrinsic and extrinsic neuronal mechanisms facilitate bridging axonal regeneration one year after spinal cord injury.Despite advances in promoting axonal regeneration after acute spinal cord injury (SCI), elicitation of bridging axon regeneration after chronic SCI remains a formidable challenge. We report that combinatorial therapies administered 6 weeks, and as long as 15 months, after SCI promote axonal regeneration into and beyond a midcervical lesion site. Provision of peripheral nerve conditioning lesions, grafts of marrow stromal cells, and establishment of NT-3 gradients supports bridging regeneration. Controls receiving partial components of the full combination fail to exhibit bridging. Notably, intraneuronal molecular mechanisms recruited by delayed therapies mirror those of acute injury, including activation of transcriptional activators and regeneration-associated genes. Collectively, these f2009-01-01T00:00:00Z2009 Oct2026-03-16T16:54:31.226Z2025-09-01T03:06:35.75ZS-EPMC27736531987478510.1016/j.neuron.2009.09.016