The following is an excerpt from a talk given at the World Congress of Dermatology in Milan on June 12, 2019
Glycation is the process by which (excess) sugars induce protein modifications. AGEs (Advanced Glycation End products) represent the final stage of glycation, when proteins and sugars become irreversibly cross-linked. Accumulation of AGEs in the ECM occurs on proteins with a slow turnover rate, with the formation of cross-links that can trap other local macromolecules. In this way, AGEs alter the properties of the large matrix proteins collagen, vitronectin, and laminin. AGE cross-linking on type I collagen and elastin causes an increase in the area of ECM, resulting in increased stiffness of the vasculature. Glycation results in increased synthesis of type III collagen, type V collagen, type VI collagen, laminin, and fibronectin in the ECM, most likely via upregulation of transforming growth factor-â pathways.
Sun-exposed areas contain significantly higher levels of two AGEs than unexposed skin.
Skin biopsy studies indicate that dermal collagen levels of AGEs like pentosidine and carboxymethyllysine (CML) correlate with aging as do skin fluorescence measured at two wavelengths (370ex/440em nm and 440ex/ 520em nm). Measurement of skin fluorescence at 440ex/520em nm may provide a non-invasive way of measuring skin AGEs and can be used as a novel claim to study skin ageing.