Zhengyuan Xia
The University of Hong Kong, China
Title: Ischemic preconditioning: Remote distance versus remote time
Biography
Biography: Zhengyuan Xia
Abstract
Brief ischemia and reperfusion to no vital organs, referred to as remote ischemic preconditioning(RIPC), can help the heart to withstand a prolonged ischemia during cardiac surgeries in non-diabetic patients. However, RIPC cardioprotection is reduced/diminished in diabetic patients with increased oxidative stress. Notably, recent large-scale clinical trials showed that RIPC, when induced immediately before surgery in patients anesthetized solely or primarily with propofol, an anesthetic reported to attenuate RIPC cardioprotection, is potentially detrimental evidenced as more than doubled1 or about 50% more patient death in the RIPC than in the sham-RIPC group, which is of clinical significance although the trials were not powered to detect statistically between-group differences. By contrast, RIPC applied before/during hospital admission increased myocardial salvage-index(area at risk-final infarct size)/area at risk) without increasing patient death. Experimentally, we demonstrated that repeated RIPC for three consecutively days reduced myocardial infarction in diabetic rats by activating mitochondrial STAT3, a key molecule in RIPC cardioprotection. RIPC at a remote time may allow the second-window cardioprotection to manifest to help better withstand ischemia during cardiac surgery and merits clinical trials to confirm.