Remote ischemic preconditioning significantly elevated the mean nervous activity of denervated myocardium compared to control rats (35.9% vs. 28.9%, p<0.05), improving cardiac sympathetic nerve innervation.
Does remote ischemic preconditioning improve cardiac sympathetic nerve innervation and metabolism in a rat model of myocardial ischemia/reperfusion injury?
Remote ischemic preconditioning preserves cardiac sympathetic nerve innervation and reduces CSPG expression following myocardial ischemia/reperfusion injury in rats, though it does not significantly affect myocardial metabolism.
Absolute Event Rate: 35.9% vs 28.9%
p-value: p=<0.05
Abstract Background Multiple potential interventions have been tested to protect the heart against myocardial ischemia/reperfusion (MIR) injury. Remote ischemic conditioning (RIC), an endogenous cardioprotective approach, could markedly improve cardiac function post-myocardial ischemia injury. In this study, we aimed to assess the effects of RIC on cardiac sympathetic nerve innervation and metabolism in the association with Chondroitin sulfate proteoglycans (GSPG). Methods Transient myocardial ischemia (30 min) is induced by ligature of the left anterior descending coronary artery ligation (LAD) in male Sprague Dawley rats (250-350 g), in vivo cardiac 11 C m HED and 2- 18 FFDG PET scans were performed at 14 days after ischemia. Remote ischemic preconditioning (RIPerc) was induced by three cycles of five-minute-long unilateral hind limb ischemia and intermittent five minutes of reperfusion during LAD occlusion period. The quantitative parameters were quantified in parametric polar maps. This standardized format facilitates the regional radioactive quantification of parameters in deficit regions to remote areas. The ex vivo radionuclide distribution was additionally identified using autoradiography. Myocardial neuron density and GSPG expression were assessed by immunohistochemistry. Results There was no significant difference in the metabolism-defected to the remote activity ratio (44.6±4.8% vs. 45.4±4.4%) between control rats (MIR) and treated (MIR+RIPerc) rats (P>0.05). Additionally, the mean nervous activity of denervated myocardium activity was significantly elevated in rats with RIPerc coupled with reduced denervated myocardium size compared to the rats MIR group (35.9±7.1% vs. 28.9±2.3% of the left ventricular (LV) remote area (P<0.05). These findings were associated with preserved LV systolic function and a significant reduction in GSPG expression in the myocardium. Conclusion RIPerc presented the effect on cardiac sympathetic nerve innervation following ischemia, but there is no significant effect on myocardial metabolism. A long-term outcome study is warranted.
Kiss et al. (Wed,) conducted a other in Myocardial ischemia/reperfusion injury (n=35). Remote ischemic preconditioning vs. Myocardial ischemia/reperfusion without preconditioning was evaluated on Mean nervous activity of denervated myocardium (% of LV remote area) (p=<0.05). Remote ischemic preconditioning significantly elevated the mean nervous activity of denervated myocardium compared to control rats (35.9% vs. 28.9%, p<0.05), improving cardiac sympathetic nerve innervation.