HGF and amyotrophic lateral sclerosis: Recent studies have revealed that HGF acts as a neurotrophic factor for a variety of neuron types [16], [17], [18], [19], [20], and that administering HGF enhances angiogenesis, improves microcirculation, inhibits destruction of the blood-brain barrier [21], and exerts a neuroprotective effect after cerebral ischemia [22], [23] and in the transgenic amyotrophic lateral sclerosis (ALS) rat model [24].