Circadian Dysfunction of Oxydative Stress and Endogenous Antioxidants with Reference to Methylglyoxa

Abstract

Circadian rhythm of increased oxidative stress and deficiency of antioxidant vitamins is known to occur in the morning at 6.00 hours to 12.00 hours [1]. Apart from antioxidant and vitamin deficiency, there is also deficiency of catalase, super-oxide-dismutase (SDO) and glutathione peroxidase (GPO) due to increased requirement of antioxidant enzymes in the morning. Methylglyoxal (MGO) is a non-enzymatic metabolite in the glycolytic pathway and its concentration in blood and tissues is elevated in all the cardio-metabolic diseases, including obesity and diabetes mellitus (DM) [1, 2]. MGO is a reactive carbonyl species (RCS) and in turn it induces tissue injuries via reactive oxygen species (ROS), resulting in increased damage of target tissues, which may worsen in the morning. MGO also plays an important pathological role in the development of both cardiovascular diseases (CVDs) and diabetes via the AGEs exert irreversible effects on protein structure and function. As such, it is crucial to understand the underlying mechanism whereby MGO is inducing tissue damage. This mini-review aims to highlight the role of circadian dysfunction in the pathogenesis of diabetes mellitus and its complications.