Dysregulated miR-21/SOD3, but Not miR-30b/CAT, Profile in Elderly Patients with Carbohydrate Metabolism Disorders: A Link to Oxidative Stress and Metabolic Dysfunction

Carbohydrate metabolism disorders (CMDs), including prediabetes and type 2 diabetes mellitus (T2DM), are increasingly prevalent in the aging population. Oxidative stress (OxS) plays a pivotal role in CMD pathogenesis, with extracellular superoxide dismutase (SOD3) and catalase (CAT) serving as critical antioxidant defenses. Additionally, microRNAs (miR-21 and miR-30b) regulate the oxidative and inflammatory pathways, yet their roles in elderly CMD patients remain unclear. This study evaluated miR-21 and miR-30b expression alongside SOD3 and CAT plasma levels in individuals aged ≥ 65 years (n = 126) categorized into control (n = 38), prediabetes (n = 37), and T2DM (n = 51) groups. Quantitative PCR assessed miRNA expression, while ELISA measured the enzyme levels. SOD3 levels were significantly reduced in CMDs, particularly in T2DM, whereas miR-21 was upregulated. A negative correlation between SOD3 and miR-21 was strongest in T2DM, suggesting a regulatory interplay. Neither CAT levels nor miR-30b expression differed among groups. Logistic regression indicated SOD3 as a protective biomarker, with each 1 ng/mL increase reducing the CMD risk by ~5-6%. The ROC analysis supported SOD3's diagnostic potential, while miR-21 showed a modest association. These findings highlight SOD3 downregulation and miR-21 upregulation as potential contributors to CMD progression in elderly patients, warranting further research into their mechanistic roles and therapeutic potential.