RESUMO
Therapeutic strategies for the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) are actually minimally effective on patients' survival and quality of life. Although stem cell therapy has raised great expectations, information on the involved molecular mechanisms is still limited. Here we assessed the efficacy of the systemic administration of adipose-derived mesenchymal stem cells (ASC), a previously untested stem cell population, in superoxide-dismutase 1 (SOD1)-mutant transgenic mice, the animal model of familial ALS. The administration of ASC to SOD1-mutant mice at the clinical onset significantly delayed motor deterioration for 4-6 weeks, as shown by clinical and neurophysiological tests. Neuropathological examination of ASC-treated SOD1-mutant mice at day 100 (i.e. the time of their best motor performance) revealed a higher number of lumbar motorneurons than in phosphate-buffered saline-treated SOD1-mutant mice and a restricted number of undifferentiated green fluorescent protein-labeled ASC in the spinal cord. By examining the spinal cord tissue factors that may prolong neuronal survival, we found a significant up-regulation in levels of glial-derived neurotrophic factor (GDNF) and basic fibroblast growth factor (bFGF) after ASC treatment. Considering that ASC produce bFGF but not GDNF, these findings indicate that ASC may promote neuroprotection either directly and/or by modulating the secretome of local glial cells toward a neuroprotective phenotype. Such neuroprotection resulted in a strong and long-lasting effect on motor performance and encourages the use of ASC in human pathologies, in which current therapies are not able to maintain a satisfying neurological functional status.
