Abstract
Bone marrow (BM) cells from amyotrophic lateral sclerosis (ALS) patients show significantly reduced expression of several neurotrophic factors. Monotherapy with either wild-type (WT) BM transplantation (BMT) or granulocyte colony-stimulating factor (GCSF) has only a small clinical therapeutic effect in an ALS mouse model, due to the phenomenon of neuroprotection. In this study, we investigated the clinical benefits of combination therapy using BMT with WT BM cells, plus GCSF after disease onset in ALS mice [transgenic mice expressing human Cu/Zn superoxide dismutase (SOD1) bearing a G93A mutation]. Combined treatment with BMT and GCSF delayed disease progression and prolonged the survival of G93A mice, whereas BMT or GCSF treatment alone did not. Histological study of the ventral horns of lumbar cords from G93A mice treated with BMT and GCSF showed a reduction in motor neuron loss coupled with induced neuronal precursor cell proliferation, increased expression of neurotrophic factors (glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor, vascular endothelial growth factor and angiogenin), and neovascularization compared with controls (vehicle only). Compared with G93A microglial cells, most BM-derived WT cells differentiated into microglial cells and strongly expressed neurotrophic factors, combined BMT and GCSF treatment led to the replacement of G93A microglial cells with BM-derived WT cells. These results indicate combined treatment with BMT and GCSF has potential neuroprotective and angiogenic effects in ALS mice, induced by the replacement of G93A microglial cells with BM-derived WT cells. Furthermore, this is the first report showing the effects of combined BMT and GCSF treatment on blood vessels in ALS.