Objective: The aim of the study was to determine whether the inhibition of the G-protein-coupled receptor kinase 2 by adenoviral βARKct cardiac gene transfer can ameliorate postresuscitation myocardial injury in pigs with cardiac arrest (CA) and explore the mechanism of myocardial protection.
Methods: Male landrace domestic pigs were randomized into the sham group (anesthetized and instrumented, but ventricular fibrillation was not induced) (n = 4), control group (ventricular fibrillation 8 min, n = 8), and βARKct group (ventricular fibrillation 8 min, n = 8). Hemodynamic parameters were monitored continuously. Blood samples were collected at baseline, 30 min, 2 h, 4 h, and 6 h after the return of spontaneous circulation (ROSC). Left ventricular ejection fraction was assessed by echocardiography at baseline and 6 h after ROSC. These animals were euthanized, and the cardiac tissue was removed for analysis at 6 h after ROSC.
Results: Compared with those in the sham group, left ventricular +dp/dtmax, -dp/dtmax, cardiac output (CO), and ejection fraction (EF) in the control group and the βARKct group were significantly decreased at 6 h after the restoration of spontaneous circulation. However, the βARKct treatment produced better left ventricular +dp/dtmax, -dp/dtmax, CO, and EF after ROSC. The βARKct treatment also produced lower serum cardiac troponin I, CK-MB, and lactate after ROSC. Furthermore, the adenoviral βARKct gene transfer significantly increased β1 adrenergic receptors, SERCA2a, RyR2 levels, and decreased GRK2 levels compared to control.
Conclusions: The inhibition of GRK2 by adenoviral βARKct cardiac gene transfer can ameliorate postresuscitation myocardial injury through beneficial effects on restoring the sarcoplasmic reticulum Ca-handling proteins expression and upregulating the β1-adrenergic receptor level after cardiac arrest.