Targeted Nrf2 activation improves vascular endothelial function with aging and prevents vascular dysfunction following disuse in younger and older adults

Aging and physical inactivity/disuse contribute to cardiovascular disease, which is attributable, in part, to vascular endothelial dysfunction associated with impaired nuclear-factor erythroid 2-related factor 2 (Nrf2) signaling. However, the ability to augment Nrf2 activation and its effects on age- and disuse-related vascular dysfunction in humans remains limited. In a double-blind, randomized, placebo-controlled study design 20 younger adults (8M/12F, age 27 ± 7 y) and 24 older adults (12M/12F, age 67 ± 8 y) were randomized to receive either placebo or PB125 (200 mg/day, Nrf2 activator) across three visits: baseline, 2 weeks of supplementation, and following either 5 days of bed rest (old) or 2 weeks of limb immobilization (young). Brachial and popliteal artery flow-mediated dilation (FMD), passive leg movement-induced (PLM) leg blood flow (LBF) and vascular conductance (LVC) and serum antioxidant status (superoxide dismutase, SOD) were assessed at each timepoint. Compared to placebo, 2 weeks of PB125 increased brachial (PB125: 2.8 ± 1.5 to 3.8 ± 1.3%, p < 0.0001) and popliteal FMD (PB125: 1.5 ± 1.5 to 2.3 ± 1.4%, p = 0.033) in older, but not younger adults (both, p > 0.27). During bed rest, PB125 preserved brachial (3.8 ± 1.3 to 3.6 ± 1.4%, p = 0.543) and popliteal FMD (2.3 ± 1.4 to 2.7 ± 1.4%, p = 0.269), LVC (1.1 ± 0.8 to 1.1 ± 1.5 AUC, p = 0.530) and circulating SOD concentrations (28.3 ± 7.2 to 28.6 ± 8.6 U/mL, p = 0.888) in older adults compared to placebo (all, p < 0.05). Following limb immobilization, PB125 preserved popliteal FMD (4.4 ± 2.8 to 3.4 ± 1.8%, p = 0.302) in younger adults compared to placebo (p < 0.05). These findings demonstrate targeted Nrf2 activation with PB125 improves age-related vascular endothelial dysfunction while preserving vascular function and antioxidant capacity following periods of disuse. Published by Elsevier Inc. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/