Development of the Treatment of Amyotrophic Lateral Sclerosis (ALS) with Neural Stem Cells

首先，我们研究了全身低氧对G93A SOD1突变小鼠血管内皮生长因子(VEGF)的诱导作用。与野生型小鼠相比，SOD1突变小鼠的基线血管内皮生长因子表达增加。与野生型小鼠相比，突变小鼠的低氧几乎不能诱导血管内皮生长因子的表达，而野生型小鼠的低氧诱导小鼠血管内皮生长因子的表达增加了约九倍，这表明在SOD1突变小鼠中，血管内皮生长因子对低氧的反应受到损害。接下来，我们研究了血管内皮生长因子受体之一的Flk-1的减少是否可以通过反义寡核苷酸(AS-ODN)抑制Flk-1的表达而导致运动神经元丢失。鞘内注射AS-ODN 7天后，腰椎节段Flk-1的表达几乎完全被抑制，随后低氧1小时，重复7天。我们观察到，Flk-1的表达减少和低氧7天可导致运动神经元损失约50%，其中Akt和ERK的激活，即低氧引起的磷酸化Akt和磷酸化ERK水平的升高，明显受到抑制。为了研究IGF-1在家族性ALS小鼠模型中的作用，采用腰髓鞘内连续注射IGF-1的方法对G93A SOD1突变小鼠进行治疗。我们发现，鞘内注射IGF-1改善了G93A转基因小鼠的运动能力，推迟了临床疾病的发生，并延长了存活时间。接下来，我们进行了一项双盲临床试验，以评估鞘内注射IGF-1对ALS患者疾病进展的影响。我们发现鞘内注射IGF-1对ALS患者有温和但显著的益处，没有任何严重的不良反应。

At first, we examined the induction of vascular endothelial growth factor (VEGF) in the G93A SOD1-mutant mice exposed to systemic hypoxia. Baseline expression of VEGF was increased in the SOD1-mutant mice compared with wild-type littermates. VEGF expression in the mutant mice was hardly induced by hypoxia, in contrast to the wild-type littermates where approximately nine-fold increase in VEGF expression was observed, indicating that the response of VEGF to hypoxia is impaired in the SOD1-mutant mice. We next investigated whether reduction of Flk-1, one of VEGF receptors, could induce motor neuron loss by inhibiting the Flk-1 expression using antisense oligodeoxynucleotides (AS-ODNs). Intrathecal infusion of AS-ODNs for 7 days suppressed almost completely Flk-1 expression in the lumbar segment, and was followed by a hypoxic challenge for 1 hour that was repeated for 7 more days. We observed that reduced Flk-1 expression and hypoxic challenge for 7 days resulted in 〜50% loss of motor neurons, in which the activation of Akt and ERK, that is increased levels of phosphorylated-Akt and of phosphorylated-ERK by hypoxia, was markedly inhibited. These results suggest that VEGF exerts its protective effect on motor neurons against hypoxia-induced toxicity by the Flk-1 receptor.To examine the possible effectiveness of IGF-1 in a mouse model of familial ALS, the G93A SOD1-mutant mice were treated by continuous IGF-1 delivery into the intrathecal space of the lumbar spinal cord. We found that the intrathecal administration of IGF-1 improved motor performance, delayed the onset of clinical disease, and extended survival in the G93A transgenic mice. Next, we performed a double blind clinical trial to assess the effect of intrathecal administration of IGF-1 on disease progression in patients with ALS. We found that the intrathecal administration of IGF-1 had a modest but significant beneficial effect in ALS patients without any serious adverse effects.