FGF1 and amyotrophic lateral sclerosis: FGF and NGF pathways are enriched in PBMCs following acute exercise and have been shown in vitro astrocytes to cause motor neuron apoptosis, which has previously been implicated in the pathophysiology of ALS (Fig. 2).27,63,64 FGF1 secretion is stimulated by oxidative stress, hypoxia and serum starvation.