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Schwann cells as a source of insulin‐like growth factor‐1 for extraocular muscles
Author(s) -
Feng Chengyuan,
Von Bartheld Christopher S.
Publication year - 2010
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.21519
Subject(s) - extraocular muscles , insulin like growth factor , growth factor , insulin , medicine , biology , endocrinology , neuroscience , anatomy , receptor
Precise force regulation is fundamentally important for extraocular muscle (EOM) function. Insulin‐like growth factor‐1 (IGF‐1) plays a major role in EOM force regulation, but the source of endogenous IGF‐1 is unclear. Multiple IGF‐1 sources may supply EOMs, including: the EOM itself; the systemic circulation; innervating motoneurons; and Schwann cells within nerves. IGF‐1 expression was measured in chicken during oculomotor system maturation by using real‐time polymerase chain reaction (PCR). Accumulation of radiolabeled IGF‐1 in EOMs was compared after either injection into the vascular circulation or into the trochlear nerve. Schwann cells were the most prominent IGF‐1 source. A microtubule‐dependent mechanism exists to anterogradely transport IGF‐1 to EOMs. EOMs were significantly more efficient in extracting IGF‐1 from the nerve than from the systemic circulation. Therefore, Schwann cells are the most prominent and potentially the most important source of IGF‐1 for EOMs. These findings may contribute to a better understanding of EOM force regulation and its failure in strabismus. Muscle Nerve, 2010