The importance of the Maillard reaction in ophtalmology

Non enzymatic glycosylation( glycation) of proteins, described by L. C. Maillard in 1912, results in the formation of advanced glycation end products (AGE-s). These exhibit a number of harmful reactions, increasing with age and involved in several age-associated pathologies. In ocular pathology, their role was demonstrated at several levels of age-associated eye-diseases, such as the rigidification of cornea, in the separation of vitreous fibers from the hyaluronan jelly, which might result in retinal detachment. AGE-s are involved also in retinal microvascular alterations in diabetics as well as in age-related macular degeneration. We compared the cytotoxic effect of several AGE-s on human skin fibroblasts and corneal keratocytes. Keratocytes were shown to be much more resistant to the cytotoxic effect of several AGE-products than fibroblasts. This higher resistance of keratocytes to the free radical mediated cytotoxic effect of AGE-s might be the result of the constant exposure of cornea to UV-light possibly mediating the appearance of more efficient protective mechanisms during evolution.