Stem cell research raises hopes for incurable neurodegenerative diseases. In 
amyotrophic lateral sclerosis (ALS), affecting the motoneurones of the central 
nervous system (CNS), stem cell-based therapy aims to replace dying host 
motoneurones by transplantation of cells in disease-affected regions. Moreover, 
transplanted stem cells can serve as a source of trophic factors providing 
neuroprotection, slowing down neuronal degeneration and disease progression.
AIM: To determine the profile of seven trophic factors expressed by mesenchymal 
stem cells (MSC) and neural stem cells (NSC) upon stimulation with CNS protein 
extracts from SOD1-linked ALS rat model.
METHODS: Culture of rat MSC, NSC and fibroblasts were incubated with brain and 
spinal cord extracts from SOD1(G93A) transgenic rats and mRNA expression of 
seven growth factors was measured by quantitative PCR.
RESULTS: MSC, NSC and fibroblasts exhibited different expression patterns. Nerve 
growth factor and brain-derived neurotropic factor were significantly 
upregulated in both NSC and MSC cultures upon stimulation with SOD1(G93A) CNS 
extracts. Fibroblast growth factor 2, insulin-like growth factor and 
glial-derived neurotropic factor were upregulated in NSC, while the same factors 
were downregulated in MSC. Vascular endothelial growth factor A upregulation was 
restricted to MSC and fibroblasts. Surprisingly, SOD1(G93A) spinal cord, but not 
the brain extract, upregulated brain-derived neurotropic factor in MSC and 
glial-derived neurotropic factor in NSC.
CONCLUSIONS: These results suggest that inherent characteristics of different 
stem cell populations define their healing potential and raise the concept of 
ALS environment in stem cell transplantation.