Advanced Glycation End Products: Association with the Pathogenesis of Diseases and the Current Therapeutic Advances

Advanced glycation end products (AGE) such as N--carboxy-ethyl-lysine (CEL), N--carboxy-methyl-lysine (CML), imidazolone, methyl-glyoxal-lysine dimer (MOLD), glyoxal-lysine dimer (GOLD), pyrraline and pentosidine have been imparted in the development and worsening of complications of diabetes. They are also involved in atherosclerosis, normal aging process, arthritis, cancer and progression of age-related neurodegenerative diseases like Alzheimer's disease. Endogenously, they are formed by nonenzymatic glycation by aldoses/ketoses to form intermediate precursor that were slowly converted into AGE. A positive correlation was observed with the level of AGEs formation and progression of the diseases. Exogenously, they formed in foods when they were cooked at very high temperature. AGEs can interact with the cell surface receptors of AGE (RAGE) to release cytokines, free radicals as well as directly modify the extracellular matrix and action of hormones. Hence, the mechanism of AGE association with pathogenesis of diseases can be ascribed mainly to the generated cytokines and free radicals. Second type of receptors such as AGE receptor-1, 2 and 3 were more specific and involved in their detoxification and clearance. Therapeutic agents were used to inhibit AGEs formation, traps the reactive carbonyl intermediate precursors, interfering with Amadori's products, cross-link breaker and low molecular weight inhibitors of RAGE had been described as well. Despite the several therapeutic agents described so far, none of them have proven to be recommended for clinical use. Furthermore, no methods or standard units were accepted universally to measure AGEs are existing. This review discusses AGEs formation, association with diseases and therapeutic agents to alleviate them.