Protective role of Nrf2 against ischemia reperfusion injury and cardiac allograft vasculopathy

Ischemia‐reperfusion injury (IRI) and cardiac allograft vasculopathy (CAV) remain unsolved complications post–heart transplant (Tx). The antioxidant transcription factor Nuclear factor erythroid 2‐related factor 2 (Nrf2) has been suggested to inhibit reactive oxygen species‐mediated NF‐κB activation. We hypothesized that Nrf2 inhibits NF‐κB activation post–Tx and suppresses IRI and the subsequent development of CAV. IRI and CAV were investigated in murine heterotopic Tx models, respectively. Nrf2 wild‐type (WT) and KO mice were used as donors. Sulforaphane was used as an Nrf2 agonist. In saline‐treated animals following 24 hours of reperfusion in isogenic grafts, Nrf2‐KO showed significantly less SOD1/2 activity compared with WT. Nrf2‐KO displayed significantly high total and phosphorylated p65 expressions and percentage of cells with nuclear p65. mRNA levels of NF‐κB‐mediated proinflammatory genes were also high. Graft dysfunction, apoptosis, and caspase‐3 activity were significantly higher in Nrf2‐KO. In the allograft studies, graft beating score was significantly weaker in Nrf2‐KO compared with WT. Nrf2‐KO also demonstrated significantly more coronary luminal narrowing. In WT animals, sulforaphane successfully augmented all the protective effects of Nrf2 with increase of SOD2 activity. Nrf2 inhibits NF‐κB activation and protects against IRI via its antioxidant properties and suppresses the subsequent development of CAV. The antioxidant transcription factor nuclear factor erythroid 2–related factor 2 inhibits nuclear factor‐kappaB activation and protects against ischemia‐reperfusion injury via its antioxidant properties and suppresses the subsequent development of cardiac allograft vasculopathy.