title: A comparative morphological, electrophysiological and functional analysis of axon regeneration through peripheral nerve autografts genetically modified to overexpress BDNF, CNTF, GDNF, NGF, NT3 or VEGF.
abstract: The clinical outcome of microsurgical repair of an injured peripheral nerve with an autograft is suboptimal. A key question addressed here is: can axon regeneration through an autograft be further improved? In this article the impact of six neurotrophic factors (BDNF, CNTF, GDNF, NGF, NT3 or VEGF) on axon regeneration was compared after delivery to a 1cm long nerve autograft by gene therapy. To distinguish between early and late effects, regeneration was assessed at 2 and 20weeks post-surgery by histological, electrophysiological and functional analysis. BDNF, GDNF and NGF exhibited a spectrum of effects, including early stimulatory effects on axons entering the autograft and excessive axon growth and Schwann cell proliferation at 20weeks post-surgery. Persistent expression of these factors in autografts interfered with target cell reinnervation and functional recovery in a modality specific way. Autografts overexpressing VEGF displayed hypervascularization, while grafts transduced with CNTF and NT3 were indistinguishable from control grafts. These three factors did not have detectable pro-regenerative effects. In conclusion, autograft-based repair combined with gene therapy for three of the six growth factors investigated (BDNF, GDNF, NGF) showed considerable promise since these factors enhanced modality specific axon outgrowth in autografts. The remarkable and selective effects of BDNF, GDNF and NGF on motor or sensory regeneration will be exploited in future experiments that aim to carefully regulate their temporal and spatial expression since this has the potential to overcome the adverse effects on long-distance regeneration observed after uncontrolled delivery.
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Hoyng
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Fred
authors.initials: F
authors.lastname: De Winter
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Department of Clinical and Biological Sciences, Neuroscience Institute of the Cavalieri Ottolenghi Foundation, University of Turin, Turin, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Gnavi
authors.affiliation: Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Ralph
authors.initials: R
authors.lastname: de Boer
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands.
authors.forename: Lennard I
authors.initials: LI
authors.lastname: Boon
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Korvers
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Department of Neurology, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Martijn R
authors.initials: MR
authors.lastname: Tannemaat
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Martijn J A
authors.initials: MJ
authors.lastname: Malessy
authors.affiliation: Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105BA Amsterdam, The Netherlands; Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV Amsterdam, The Netherlands. Electronic address: j.verhaagen@nin.knaw.nl.
authors.forename: Joost
authors.initials: J
authors.lastname: Verhaagen
mesh_terms: D000818:Animals; D000842:Ankle / Q000294:innervation; D064592:Autografts / Q000378:metabolism / Q000502:physiology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005822:Genetic Vectors / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009038:Motion; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D020932:Nerve Growth Factor / Q000096:biosynthesis* / Q000627:therapeutic use*; D009416:Nerve Regeneration / Q000187:drug effects*; D017288:Pain Threshold; D010523:Peripheral Nervous System Diseases / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000502:physiology; D013997:Time Factors; D014182:Transplantation, Autologous
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D020932:Nerve Growth Factor
keywords: Gene therapy; Neurotrophic factor; Peripheral nerve repair; Schwann cell; Viral vector