INSULIN-LIKE GROWTH-FACTOR-I RECEPTORS IN HUMAN SPINAL-CORD - CHANGES IN AMYOTROPHIC-LATERAL-SCLEROSIS

Neurotrophic factors are important for neuronal survival and maintenance in the adult nervous system. The regional distribution of insulin-like growth factor-1 (IGF-1) receptors in human spinal cords from controls and amyotrophic lateral sclerosis (ALS) patients was studied by immunohistochemistry and quantitative autoradiography. When comparing I-125-IGF-1 binding in the different spinal levels of normal spinal cord the same distribution pattern was found in which the binding was highest in the central canal > dorsal horn > ventral horn > white matter. In the ALS cases although a general upregulation of IGF-1 receptors was observed throughout the spinal cord, significant increases were observed in the cervical and sacral segments compared to controls. IGF-I receptor immunoreactivity showed a similar pattern to that for I-125-IGF-1 binding, with immunoreactivity being found in the gray matter of the spinal cord and enhanced immunoreactivity occuring in ALS patients compared to controls. In agreement with the distribution of IGF-1 receptors, IGF-1 immunoreactivity was found within the gray matter of the spinal cord. The cartography of IGF-1 receptors in the normal spinal cord as well as the change of these receptors in diseased spinal cord may be of importance in future treatment strategies of ALS.