My 900th curation is a 2022 review by the lead author of Reversibility of AGEs concentrations that fleshed out details of advanced glycation end products (AGEs) topics:
“This review aims to provide a state-of-the-art overview of the toxicokinetics and toxicodynamics of endogenously formed and exogenous dietary AGEs and their precursors. AGEs are a heterogenous group of:
- Low molecular mass (LMM) glycation products formed by reaction with a free amino acid residue and/or to dicarbonyl precursors; and
- High molecular mass (HMM) glycation products formed by reaction with a protein-bound amino acid residue, including cross-linked products (i.e. when two amino acid residues are involved instead of one).
Cross-linking of body proteins results in:
- Altered structure and function of the proteins;
- Proteins are less easily degraded;
- An increase in stiffness in tissues that are rich in these proteins, including arterial, lung tissue, joints, and extracellular matrix. Stiffness in these tissues has been associated with diseases including hypertension, cataracts, dementia, atherosclerosis, glomerulosclerosis, emphysema, and joint pain.
In endogenous formation of AGEs and their precursors, the same pathways as exogenous proceed via non-enzymatic reactions, although they occur at lower rates due to the lower physiological temperatures. In addition, specific endogenous AGE formation pathways include glycolysis and the polyol pathway active under hyperglycemic conditions.
Considering heterogeneity of glycation products, as also reflected in different ADME outcomes, AGEs and their precursors cannot be grouped together. Specific, individual information is required for a proper evaluation, especially considering ADME properties.
The role of exogenous HMM AGEs and precursors seems to be restricted by limited bioavailability to local effects on the intestine including its microbiota, unless being degraded to their LMM form. An important role is probably left for reactive (endogenously formed) dicarbonyl AGE precursors and as a consequence the endogenously formed AGEs.
The direct contribution of reactive dicarbonyl precursors to dicarbonyl stress and their indirect contribution to endogenous HMM AGE formation and subsequent AGE receptor activation remain to be further studied.”
https://www.sciencedirect.com/science/article/pii/S0278691522001855 “Differences in kinetics and dynamics of endogenous versus exogenous advanced glycation end products (AGEs) and their precursors”