The role of oxygen in the formation of fluorescent advanced glycation end products from α-dicarbonyl compounds

Background Advanced glycation end products (AGEs) are heterogeneous compounds that can be endogenously generated and can also be exogenously consumed through heated food. The AGEs accumulate in cells and tissues over time, increasing oxidative stress and thereby contributing to the aging process via inflammation. The physiological oxygen concentration in tissues is significantly lower than atmospheric oxygen (~21%); however, most experimental studies have been conducted under atmospheric conditions rather than physiologically relevant oxygen levels. Objective This study aims to assess the oxygen-dependent formation of AGEs induced by glyoxal (GO) and methylglyoxal (MGO) in vitro. Material and methods In this study, the AGE-associated fluorescence intensity was measured in human serum albumin (HSA) incubated with GO or MGO under different oxygen concentrations using a CLARIOstar plate reader. Fluorescent AGEs were quantified using excitation wavelengths of 330/360 nm and emission wavelengths of 405/440 nm. Non-fluorescent AGEs, such as carboxymethyl lysine (CML) and methylglyoxal-derived hydroimidazolone1 (MG-H1), were detected via immunoblotting. Results The formation of AGEs increased following incubation of HSA with GO or MGO, showing clear concentration-dependent and time-dependent patterns. No statistically significant differences were observed among the tested oxygen conditions. Conclusion These findings suggest that under the experimental conditions used in this in vitro study, glycation did not significantly differ across the tested oxygen conditions. Further investigation is warranted to explore the impact of oxygen on glycation in vivo, where additional regulatory mechanisms could play a role.