Diabetes and Estrogen: The Role of Oxidative Stress on Endothelial Function in Women

Abstract

Approximately 30 million people in the United States carry the diagnosis of diabetes mellitus (DM). A major co-morbid complication of DM is cardiovascular disease, which is preceded by endothelial dysfunction. Patients with DM are thought to be in a constant state of oxidative stress due to excessive free radicals produced by cells in a hyperglycemic environment. Under healthy conditions, estrogen increases the availability of nitric oxide and the vessels' dilatory capacity. However, these effects of estrogen on the endothelium are thought to be reversed in states of oxidative stress, such as DM. Purpose: The present study sought to determine if endogenous concentrations of estrogen contributes to a reduction in flow-mediated dilation (FMD) in women with DM, and if administration of an antioxidant cocktail (AOC) improves FMD. Methods: 6 women diagnosed with DM and 15 apparently healthy controls were recruited for this study. FMD, a test to non-invasively assess endothelial function, was performed during menses (M) and the late follicular (F) phases in both patients and controls. During the F phase, FMD was assessed again 2 hours following an AOC only in patients with DM. Results: Absolute change in FMD(%) from M to F phase was different (P = 0.016) between patients with DM (-1.06±3.70 %) and controls (4.38±4.53 %). The change in FMD after AOC in women with DM was 2.97±3.42 %, which eliminated the pre AOC F phase difference in FMD between patients and controls. Conclusion These data suggest that DM negatively impacts the natural increase in FMD across the menstrual cycle and that the estrogen/oxidative stress interaction may be a contributing factor.