Effect of NT-3 on reinnervation of the larynx using the phrenic nerve transfer t

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Eur J Neurosci. 2007 Jan;25(2):331-40.

Effect of neurotrophin-3 on reinnervation of the larynx using the

phrenic nerve transfer technique.

Kingham PJ, A, Mitchard L, Burt R, Murison P, A,

Terenghi G, Birchall MA.

Blond McIndoe Research Laboratories, Plastic and Reconstructive

Surgery Research, Stopford Building, University of Manchester,

Oxford Road, Manchester, M13 9PT, UK.

Current techniques for reinnervation of the larynx following

recurrent laryngeal nerve (RLN) injury are limited by synkinesis,

which prevents functional recovery. Treatment with neurotrophins

(NT) may enhance nerve regeneration and encourage more accurate

reinnervation. This study presents the results of using the phrenic

nerve transfer method, combined with NT-3 treatment, to selectively

reinnervate the posterior cricoarytenoid (PCA) abductor muscle in a

pig nerve injury model.

RLN transection altered the phenotype and morphology of laryngeal

muscles. In both the PCA and thyroarytenoid (TA) adductor muscle,

fast type myosin heavy chain (MyHC) protein was decreased while slow

type MyHC was increased. These changes were accompanied with a

significant reduction in muscle fibre diameter. Following nerve

repair there was a progressive normalization of MyHC phenotype and

increased muscle fibre diameter in the PCA but not the TA muscle.

This correlated with enhanced abductor function indicating the

phrenic nerve accurately reinnervated the PCA muscle. Treatment with

NT-3 significantly enhanced phrenic nerve regeneration but led to

only a small increase in the number of reinnervated PCA muscle

fibres and minimal effect on abductor muscle phenotype and

morphology. Therefore, work exploring other growth factors, either

alone or in combination with NT-3, is required.