During long standing hyperglycaemic state in
diabetes mellitus,
glucose forms covalent adducts with the
plasma proteins through a non-enzymatic process known as glycation. Protein glycation and formation of
advanced glycation end products (AGEs) play an important role in the pathogenesis of
diabetic complications like retinopathy, nephropathy, neuropathy,
cardiomyopathy along with some other diseases such as
rheumatoid arthritis,
osteoporosis and aging. Glycation of
proteins interferes with their normal functions by disrupting molecular conformation, altering enzymatic activity, and interfering with receptor functioning. AGEs form intra- and extracellular cross linking not only with
proteins, but with some other endogenous key molecules including
lipids and
nucleic acids to contribute in the development of
diabetic complications. Recent studies suggest that AGEs interact with plasma membrane localized receptors for AGEs (RAGE) to alter intracellular signaling, gene expression, release of pro-inflammatory molecules and
free radicals. The present review discusses the glycation of
plasma proteins such as
albumin,
fibrinogen,
globulins and
collagen to form different types of AGEs. Furthermore, the role of AGEs in the pathogenesis of
diabetic complications including retinopathy,
cataract, neuropathy, nephropathy and
cardiomyopathy is also discussed.