The Role of Inflammation, Oxidative Stress, Neuronal Damage, and Endothelial Dysfunction in the Neuropathology of Cognitive Complications in Diabetes: A Moderation and Mediation Analysis

Abstract

ObjectiveCognitive impairment is increasingly recognized as a complication of diabetes, yet the underlying pathology remains unclear. This study aims to investigate the roles of inflammation, oxidative stress, endothelial dysfunction, and neuronal damage in the neuropathology underlying diabetes related cognitive impairment.MethodsThis study assessed 183 participants (54 prediabetes, 71 Type 2 diabetes mellitus [T2DM], and 58 controls) for cognitive performance using the Montreal Cognitive Assessment (MoCA). Blood samples were analyzed for interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), malondialdehyde (MDA), VCAM-1/CD106, and neuron-specific enolase (NSE) using ELISA. Mediation and moderator analysis methods were used to examine the roles of these biomarkers in diabetes-related cognitive impairment.ResultsAfter adjusting for age, education, and gender, group comparisons revealed significant cognitive impairment in patients with T2DM, particularly in visuospatial functions, naming, language, and memory performance, compared to the control group. The patients with T2DM and prediabetes exhibited similar performance in cognitive functions, except for language. Significant differences in VCAM-1 and TNF-alpha levels were observed; however, these biomarkers did not mediate the effect of T2DM and prediabetes on cognitive functions. Nevertheless, VCAM-1 was found to moderate abstraction abilities in T2DM.ConclusionPrediabetes represents a transitional stage not only for the pathology of diabetes but also for cognitive complications. Although there were correlations between cognitive performance and various cognitive scores, IL-6, MDA, NSE, VCAM-1, and TNF-alpha did not play a mediator role in the neuropathology of diabetes-related cognitive impairment.