[The significance of the Maillard reaction in human physiology].

More than 50 years after Maillard's original paper describing the reaction of amino acids with glucose it was found that this reaction also occurs under physiological conditions in the human body. Initially, it was discovered that human hemoglobin contains protein-bound Amadori-products that are increased in diabetic patients with elevated blood glucose levels. Measurements of fructosylated hemoglobin are now widely used as an index of glycemia in diabetes. It was soon recognized that this postribosomal modification is common to other proteins in vivo like albumin, lens crystallins, proteins of the clotting cascade, collagens, lipoproteins, proteins of the cell membrane, and others. This may lead to alterations in structure and function of the respective protein. Later, the realization that long-lived proteins become browned, fluorescent, and insoluble with age, and at an accelerated rate in diabetes, suggested that later stages of the Maillard reaction might proceed in vivo and contribute to some of the pathophysiology associated with both aging and diabetes. Although the contribution of the Maillard products to the development of diabetic late complications is not fully understood, attempts are being made to prevent formation of late Maillard product with aminoguanidine, a drug currently under clinical testing.