EXPRESSION OF CILIARY NEUROTROPHIC FACTOR IS MAINTAINED IN SPINAL MOTOR-NEURONS OF AMYOTROPHIC-LATERAL-SCLEROSIS

Ciliary neurotrophic factor (CNTF) was originally identified as a pote nt survival factor for a variety of neuronal cell types in vitro and i n vivo and in particular in spinal motor neurons of embryonic chick an d rat. Using a monoclonal antibody against CNTF (clone 4-68) we analys ed the expression of CNTF in paraffin sections of seven human brains a nd spinal cords immunocytochemically using the ABC method and compared these results with sections of the spinal cords of patients suffering from amyotrophic lateral sclerosis (ALS). In normal human tissue of t he central nervous system CNTF immunoreactivity was found in most of t he motor neurons of the motor cortex and ventral horn, neurons of the nucleus oculomotorius, intermediolateralis, thoracicus, ependymal cell s as well as in smooth muscle cells and endothelial cells of small art eries. A reduced number of astrocytes showed a positive immunocytochem ical reaction. In peripheral nerves and nerve roots of the spinal cord we also found a positive staining of Schwann cells and some axons. Th ese immunoreactions could be confirmed by Western blot analyses. Next we analysed postmortem paraffin sections of the spinal cord of seven p atients suffering from ALS (age range 30-76 years, median age 46 years , female/male = 4:3). We found CNTF immunoreactivity in most of the mo tor neurons of the ventral horn in 5 cases. In two cases the number of positively stained motor neurons was less. From these results we conc lude that CNTF is expressed in a high number of upper and lower motor neurons in the human CNS and that its expression is maintained in ALS patients.