While the analysis of isolated retinal vessels does not permit to discriminate between endothelial cells and pericytes/vascular smooth muscle cells as the source of IL-1β, the HG-induced upregulation of the cytokine in cultured endothelial cells proposes vascular endothelium as a cellular source of IL-1β overexpression in response to hyperglycemia. This evidence concerns the gene IL1B and Hyperglycemia.