Methylglyoxal-induced glycation stress promotes aortic stiffening: putative mechanistic roles of oxidative stress and cellular senescence

Background: Here, we assessed the role of the advanced glycation end-product (AGE) precursor methylglyoxal (MGO) and its non-crosslinking AGE MGO-derived hydroimidazolone (MGH)-1 in aortic stiffening and explored the potential of a glycation stress-lowering compound (Gly-Low) to mitigate these effects.

Methods: Young (3–6 month) C57BL/6J mice were supplemented with MGO (in water) and Gly-Low (in chow). Aortic stiffness was assessed in vivo via pulse wave velocity (PWV) and ex vivo through elastic modulus. Putative mechanisms underlying MGO- and MGH-1-induced aortic stiffening were explored using complementary experimental approaches in aortic tissue and cultured human aortic endothelial cells (HAECs). Moreover, aortic stiffness was assessed in old C57BL/6J (24 month) mice after consumption of Gly-Low-enriched chow.

Results: MGO-induced glycation stress increased PWV in young mice by 21% (P<0.05 vs. control), which was prevented with Gly-Low (P=0.93 vs. control). Ex vivo, MGO increased aortic elastic modulus ~100% (P<0.05), superoxide production by ~40% (P<0.05), and MGH-1 expression by 50% (P<0.05), which were all mitigated by Gly-Low. Chronic MGO exposure elevated biomarkers of cellular senescence in HAECs, comparable to a known senescence inducer Doxorubicin, an effect partially blocked by Gly-Low. Moreover, elevated aortic elastic modulus induced by Doxorubicin (P<0.05 vs. control) was prevented with Gly-Low (P=0.71 vs. control). Aortic RNA sequencing implicated preservation of endogenous cellular detoxification pathways with Gly-Low following exposure to MGH-1. Old mice supplemented with Gly-Low had lower PWV (P<0.05) relative to old control mice.

Conclusions: MGO-induced glycation stress contributes to aortic stiffening and glycation stress lowering compounds hold promise for mitigating these effects.