Disruption of Circadian Rhythms by Shift Work Exacerbates Reperfusion Injury in Myocardial Infarction

BACKGROUND Shift work is associated with increased risk of acute myocardial infarction (AMI) and worsened prognosis. However, the mechanisms linking shift work and worsened prognosis in AMI remain unclear. OBJECTIVES This study sought to investigate the impact of shift work on reperfusion injury, a major determinant of clinical outcomes in AMI. METHODS Study patient data were obtained from the database of the EARLY-MYO-CMR (Early Assessment of Myocardial Tissue Characteristics by CMR in STEMI) registry, which was a prospective, multicenter registry of patients with ST-segment elevation myocardial infarction (STEMI) undergoing cardiac magnetic resonance (CMR) imaging after reperfusion therapy. The primary endpoint was CMR-defined post-reperfusion infarct size. A secondary clinical endpoint was the composite of major adverse cardiac events (MACE) during follow-up. Potential mechanisms were explored with the use of preclinical animal AMI models. RESULTS Of 706 patients enrolled in the EARLY-MYO-CMR registry, 412 patients with STEMI were ultimately included. Shift work was associated with increased CMR-defined infarct size (beta = 5.94%; 95% CI: 2.94-8.94; P < 0.0001). During a median follow-up of 5.0 years, shift work was associated with increased risks of MACE (adjusted HR: 1.92; 95% CI: 1.12-3.29; P = 0.017). Consistent with clinical findings, shift work simulation in mice and sheep significantly augmented reperfusion injury in AMI. Mechanism studies identified a novel nuclear receptor subfamily 1 group D member 1/cardiotrophin-like cytokine factor 1 axis in the heart that played a crucial role in mediating the detrimental effects of shift work on myocardial injury. CONCLUSIONS The current study provided novel findings that shift work increases myocardial infarction reperfusion injury. It identified a novel nuclear receptor subfamily 1 group D member 1/cardiotrophin-like cytokine factor 1 axis in the heart that might play a crucial role in mediating this process. (C) 2022 by the American College of Cardiology Foundation.