Preconditioning with Maillard reaction products improves antioxidant defence leading to increased stress tolerance in cardiac cells

Advanced glycation end products (AGEs) are considered as biomarkers of ageing and are associated with several degenerative diseases. Besides endogenous formation, significant amounts of AGEs are taken up with food. Although nutritional AGEs are considered as undesirable, proinflammatory agents, they may also enclose potentially beneficial antioxidants. We used rodent cardiac cells to evaluate if food AGEs, present in bread crust, can modify the cellular antioxidant defence. Mice were fed with bread crust containing diet to prove the in-vivo relevance for the heart. In mouse cardiac fibroblasts, bread crust extract induced a moderate elevation of ROS production causing an activation of p42/p44^MAPK, p38^MAPK and NF-κB, followed by increased expression of antioxidative enzymes. Preconditioning studies demonstrated that this was sufficient to protect cardiac fibroblasts and rat adult cardiac myocytes against severe oxidative stress. Furthermore, mice, fed a bread crust containing diet, exhibited a similarly improved cardiac expression of antioxidative defence genes. The consumption of AGEs can therefore contribute to an improved antioxidant status of the heart, thus exhibiting cardioprotective effects in case of severe oxidative stress as in ischemia reperfusion injury. Also, these data show that the exclusive interpretation of circulating AGEs as pathophysiological biomarkers of ageing might be misleading.