In both pre-clinical and clinical studies, GLP-1 seemed to improve endothelial dysfunction only with concomitant hyperglycemia, as reported in studies on rat mesenteric arteries (Salheen et al., 2015; Bangshaab et al., 2019) and subcutaneous human arterioles (Koska et al., 2015). This evidence concerns the gene GCG and Hyperglycemia.