The expression of GLP-1R in retinal pericytes and ganglion cells was previously demonstrated (15), while GLP-1/GLP-1R was also reported to produce beneficial effects under the condition of hyperglycemia (16), suggesting that GLP-1/GLP-1R has protective effects on the integrity of retina in the first phases of DR caused by diabetes (3). The gene discussed is GCG; the disease is diabetes mellitus.