The Influence of Diabetes Mellitus and Kidney Dysfunction on Oxidative Stress, a Reflection of the Multisystem Interactions in Aortic Stenosis

Progression of aortic stenosis (AS) is aggravated by type 2 Diabetes Mellitus (T2DM) and kidney dysfunction (KD). Oxidative stress is one of the main mechanisms that triggers AS and is also disturbed among subjects with T2DM and KD. Consequently, we studied the redox homeostasis in four groups of patients, also classifying each patient based on their kidney function: control subjects, T2DM, AS, and AS+T2DM. Free reduced thiols in plasma were analyzed using a colorimetric assay, and the redox state of human serum albumin (HSA) was assessed by immunodetection and PEG-PCMal labeling. Lower levels of thiols were evident in patients with AS and AS+T2DM, while reduced and mildly oxidized HSA was more abundant in T2DM and AS+T2DM patients, reflecting less protection against oxidation. Moreover, the thiol levels decreased as KD increased in patients with AS and AS+T2DM. Differences also exist in reduced and mildly oxidized HSA between patients with normal and severely impaired kidney function, whereas AS patients with severe KD had more strongly oxidized HSA. Our results confirm an imbalance in oxidative stress associated with AS that is aggravated by the coexistence of T2DM and KD. Moreover, T2DM treatment might mitigate this dysfunction, opening the door to new therapeutic approaches for these patients.