Age-related differences in the effects of α and γ peroxisome proliferator-activated receptor subtype agonists on endothelial vasodilation in human microvessels

► Aging impairs endothelial dilation in human vessels independently of other risk factors. ► PPARγ agonist attenuates endothelial impairment in vessels from adult and elderly subjects. ► Improving effects of PPARα agonist on endothelial dilation is lost in aged human vessels. ► Superoxide contributes to endothelial impairment only in vessels from elderly subjects. ► Aging could impact the efficacy of therapeutic strategies to improve endothelial function.