IGF1 and Parkinson disease: As described before, the GH/IGF-1 axis is involved in brain development, growth and function; so its progressive decrease during aging could be embroiled in the establishment of several human cerebrovascular diseases, that lead to neuronal degeneration and dysfunction, such as PD, multiple system atrophy, Lewy body disease, Alzheimer’s disease, vascular dementia, amyotrophic lateral sclerosis, stroke, etc. [131–133].