The Search for the Receptor for Advanced Glycation End-Products in Avian Vasculature

Abstract

Advanced glycation end-products (AGEs) are the products of a non-enzymatic reaction that occurs in the blood between glucose and albumin. The receptor for advanced glycation end-products (RAGE) is a transmembrane protein primarily located in the endothelial cells of small vasculature which binds AGEs. When RAGE binds to its ligands, it activates a chronic inflammatory response in the genes. While this is most likely a natural immune response, in diseases that result in chronically high levels of AGEs in the blood, such as diabetes, the chronic inflammation can cause damage to the vasculature. This occurs by altering the microenvironment of the basal membrane in tissues where RAGE is expressed. Complications such as edema, retinopathy, nephropathy and cardiovascular disorders can result from this inflammation. Birds have an average fasting blood glucose level 4-5 times higher than that of a human being, making them an ideal animal model for studying adaptation to chronic high blood glucose levels. Additionally, they , do not suffer from these RAGE-related inflammatory disorders. This suggests that RAGE may not be present in birds. Tissue from Mourning Doves (Zenaida macroura) was examined for the presence of RAGE through antibody based protein identification techniques. Though not strongly conclusive, the evidence suggests that RAGE is not present in the small vasculature of Mourning Doves.