EN
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease leading to degeneration and loss of motoneurons in the spinal cord anterior horns. Although etiology of the disease is unknown there is a hypothesis assuming that survival motor neuron protein (SMN) may save motoneurons from degeneration not only in spinal muscular atrophy (SMA) but also in ALS. In animal models of ALS the neuroprotective role of SMN was observed but it is not known whether the phenomenon is present in humans. Therefore we decided to examine immunoexpression of SMN and functionally associated with it gemin 2, 3 and 4 in the anterior horn neurons of patients with sporadic form of ALS (sALS). Material and methods: The material was composed of 10 spinal cords of patients with sALS who died at the age of 52–87 years 1–8 years after the onset of the disease. On formalin-fixed and paraffin-embedded spinal cords immunohistochemistry was applied. The immunohistochemical reactions were performed with antibodies against SMN and gemin 2, 3 and 4 according to the avidin-biotin-peroxidase method. Results: In all the examined cases expression of SMN and gemin 3 in spinal cord neurons was found although intensity of the immune reactions was diverse. The immunolabel were the most intense in patients with acute course of sALS and gradually decreased with longevity of the disease. Not only motoneurons but also interneurons and sensory neurons revealed immunoexpression of SMN and gemin 3. The immune reaction to gemin 2 was negative. The immunoreactivity for gemin 4 was also negative or very weak. Conclusions: (1) In humans, expression of SMN and gemin 3 in neurons is present through the whole lifespan. (2) In sALS, expression of gemin 2 and 4 is abnormal: absent or diminished respectively. (3) Presence of all components of the SMN-gemin complex is probably necessary for its normal functioning. (4) Since the immunoreactivity for SMN, and gemin 2, 3 and 4 was similar in all the examined cases and 6 from the 10 cases were at the age of 65–87 years it seems that advanced age has no influence on expression of the investigated proteins. This study was supported by the Ministry of Science and Higher Education grant NN 401 014640