Increased oxidative stress and inflammation causally contribute to cardiovascular diseases, for which advanced age is a major risk factor. We found that indicators of oxidative stress, including NADPH oxidase activity and superoxide levels, were significantly increased in aortas of old (22-24 months) versus young (3-4 months) male F344 rats, whereas superoxide dismutase (SOD) activity was decreased. Aortic mRNA and protein levels of NOX4, the principal catalytic subunit of NADPH oxidase in vascular cells, also were increased with age, but not NOX2 and p22(phox). Indicators of inflammation, including activation of NFkappaB and upregulation of vascular cell adhesion molecule-1 (VCAM-1) in aorta, and monocyte chemotactic protein-1 (MCP-1) in plasma, also were significantly increased in old rats. Supplementation with 0.2% (wt/wt) (R)-alpha-lipoic acid (LA) for 2 weeks caused a nonsignificant decrease in NADPH oxidase activity in aged aorta and a significant decrease in mRNA--but not protein--levels of NOX4 and VCAM-1. Furthermore, LA reversed the age-dependent changes in aortic SOD activity and plasma MCP-1 levels. Hence, vascular oxidative stress and inflammation increase with age and are ameliorated by LA supplementation.