GCG and diabetes mellitus: Importantly, the role of glucagon-like peptide-1 (GLP-1) receptor agonist Lixisenatide, an incretin mimetics drug, is already known in the treatment of diabetes, with established neuroprotection in rodent models of stroke, and Alzheimer’s and Parkinson’s disease [34], and its efficacy was recently confirmed in the treatment of motor disability described in a large cohort of patients with early Parkinson’s disease, in a phase 2, double-blind, randomized, placebo-controlled trial (https://clinicaltrials.gov/ ID NCT03439943 (accessed on 13 June 2018) [35]).