Response to Antioxidants and Endothelial Dysfunction in Young and Elderly People: Is Flow-Mediated Dilation Useful to Assess Acute Effects?

Recently, our group published a study in Hypertension that used flow-mediated vasodilation (FMD) and reactive hyperemia to assess the impact of an enteral antioxidant (AO) mixture, of known efficacy, on the endothelial dysfunction associated with aging.1 In a Letter to the Editor, Tsikas et al2 expressed some concern regarding the divergent FMD and assay results between the young and old subjects in our study and also challenged the informational value of FMD. Regarding the results of the assay-based assessments of NO and oxidative stress performed in our study, it should be noted that AO consumption did not actually alter biomarkers of oxidative stress or NO in the young (Table 2 in Reference 1), and, thus, the statement that our findings “show even increases in oxidative stress and decreases in [FMD] in young people” is, in fact, incorrect. In addition, previous studies from our group using electron paramagnetic …