Intraaxonal uptake and transport of marker proteins: novel ways of tracing peripheral nerve regeneration.
Disruption of peripheral nerve continuity occurs after accidents or in obstetrics. Brachial plexus palsy is accompanied by loss of function of the upper extremity. For optimal regeneration, surgical reconstruction should be performed within 6 months after injury. Postoperative monitoring is difficult because reliable diagnostic tools are not available. Here we present a hypothesis how to monitor peripheral nerve regeneration taking into account two intriguing features of nerve repair. First, the nerve itself with its numerous axons has been neglected as transportation pathway hitherto. Second, growth associated proteins are exclusively upregulated during peripheral nerve repair and development providing excellent target molecules. Contrast media could be designed using truncated forms of these proteins. Previous studies showed that peripheral nerves have the ability to incorporate proteins with a size up to 240 kDa. After wounding, growth associated proteins are transported intraaxonally and incorporated into growth cone membranes. We hypothesize that injection of contrast media close to nerve cell bodies or into the end organ of the injured nerve would lead to protein uptake and transport to the injury site. Sprouting of peripheral nerves could be monitored by magnetic resonance imaging or single photon emission computer tomography using adequate tracer-coupled proteins. By this new method, nerve repair could be monitored non-invasively, selectively and repeatedly. Less contrast media at lower price would be needed and only the injured part of the body would be exposed to the diagnostic apparatus. Aberrant nerve repair could be detected easily followed by surgical therapy within the critical time frame of sustained nerve regeneration.
Mirastschijski
Ursula
U
Department of Plastic, Hand and Reconstructive Surgery, Burn Center, Hannover Medical School, Germany. Mirastschijski.Ursula@mh-hannover.de
Vogt
Peter M
PM
D001369:Axons; D006801:Humans; D008962:Models, Theoretical; D009416:Nerve Regeneration; D017933:Peripheral Nervous System / Q000502:physiology*; D021381:Protein Transport