This work was designed to explore efficacy of apelin-12 (A-12) as a cardioprotective agent when given before ischemia or at reperfusion using the isolated working heart model. Hearts of male Wistar rats were subjected...This work was designed to explore efficacy of apelin-12 (A-12) as a cardioprotective agent when given before ischemia or at reperfusion using the isolated working heart model. Hearts of male Wistar rats were subjected to 30-min stabilization period followed by 35-min global ischemia and 30-min reperfusion. A short-term infusion of Krebs-Henseleit buffer (KHB) con-taining A-12 (35, 70, 140, 280 or 560 ?M) was ap-plied prior to ischemia (A-12-I) or at onset of reperfusion (A-12-R). KHB infusion was used as control. A-12 infusions induced a dose-dependent increase in recovery of coronary flow, contractile and pump function during reperfu-sion, with the largest augmentation of these indices in the A-12-I group. Both A-12 groups exhibited a significant reduction of LV diastolic pressure rise during reperfusion compared with control. Enhanced functional recovery in the A-12-I group was combined with a decrease in LDH leakage in perfusate on early reperfusion (by 36% vs. control, p < 0.05). Preischemic infusion of 140 ?M A-12 markedly increased myocardial ATP content, enhanced preservation of the total adenine nucleotide pool and improved recovery of the energy charge in reperfused hearts. There was a trend towards increase in myocardial phosphocreatine by the end of re- perfusion in the A-12-I group;however this benefit did not reach statistical significance. At the end of reperfusion, myocardial lactate and lactate/pyruvate ratio were on average 5-fold lower in A-12-I treated hearts compared with control ones and did not differ significantly from the initial values. Therefore, improved cardiac dysfunction after I/R injury and less cell mem-brane damage induced by A-12 are associated with maintaining high energy phosphates, particularly ATP, in reperfused myocardium. Changes in energy metabolism may play a role in mechanisms of cardioprotection afforded by A-12 during I/R stress.展开更多
The adipocytokine apelin is capable to reduce myocardial ischemia/reperfusion injury in rodents. Cardioprotective activity of apelin may be attributed to upregulation of endothelial nitric oxide synthase (eNOS). This ...The adipocytokine apelin is capable to reduce myocardial ischemia/reperfusion injury in rodents. Cardioprotective activity of apelin may be attributed to upregulation of endothelial nitric oxide synthase (eNOS). This study was designed to examine metabolic and functional effects of a synthesized 12 C-terminal residue of apelin (A-12) and NG-nitro-L-arginine methyl ester (L-NAME), a non-selective eNOS inhibitor, in isolated working rat hearts subjected to global ischemia. Preischemic infusion of A-12 increased recovery of cardiac function during reperfusion compared with control and resulted in enhanced restoration of myocardial ATP, adenine nucleotide pool, phosphocreatine and reduction of myocardial lactate and lactate/pyruvate ratio. Coadministration of A-12 and L-NAME aggravated recovery of coronary flow and cardiac function compared with these indices after A-12 treatment. Cardiac dysfunction was associated with increase in lactate dehydrogenase release in myocardial effluent, reduction of glucose oxidation and abolishment of augmented restoration of high energy phosphates. The results clearly demonstrate involvement of NOS-dependent mechanisms in cardioprotection afforded by apelin.展开更多
文摘This work was designed to explore efficacy of apelin-12 (A-12) as a cardioprotective agent when given before ischemia or at reperfusion using the isolated working heart model. Hearts of male Wistar rats were subjected to 30-min stabilization period followed by 35-min global ischemia and 30-min reperfusion. A short-term infusion of Krebs-Henseleit buffer (KHB) con-taining A-12 (35, 70, 140, 280 or 560 ?M) was ap-plied prior to ischemia (A-12-I) or at onset of reperfusion (A-12-R). KHB infusion was used as control. A-12 infusions induced a dose-dependent increase in recovery of coronary flow, contractile and pump function during reperfu-sion, with the largest augmentation of these indices in the A-12-I group. Both A-12 groups exhibited a significant reduction of LV diastolic pressure rise during reperfusion compared with control. Enhanced functional recovery in the A-12-I group was combined with a decrease in LDH leakage in perfusate on early reperfusion (by 36% vs. control, p < 0.05). Preischemic infusion of 140 ?M A-12 markedly increased myocardial ATP content, enhanced preservation of the total adenine nucleotide pool and improved recovery of the energy charge in reperfused hearts. There was a trend towards increase in myocardial phosphocreatine by the end of re- perfusion in the A-12-I group;however this benefit did not reach statistical significance. At the end of reperfusion, myocardial lactate and lactate/pyruvate ratio were on average 5-fold lower in A-12-I treated hearts compared with control ones and did not differ significantly from the initial values. Therefore, improved cardiac dysfunction after I/R injury and less cell mem-brane damage induced by A-12 are associated with maintaining high energy phosphates, particularly ATP, in reperfused myocardium. Changes in energy metabolism may play a role in mechanisms of cardioprotection afforded by A-12 during I/R stress.
文摘The adipocytokine apelin is capable to reduce myocardial ischemia/reperfusion injury in rodents. Cardioprotective activity of apelin may be attributed to upregulation of endothelial nitric oxide synthase (eNOS). This study was designed to examine metabolic and functional effects of a synthesized 12 C-terminal residue of apelin (A-12) and NG-nitro-L-arginine methyl ester (L-NAME), a non-selective eNOS inhibitor, in isolated working rat hearts subjected to global ischemia. Preischemic infusion of A-12 increased recovery of cardiac function during reperfusion compared with control and resulted in enhanced restoration of myocardial ATP, adenine nucleotide pool, phosphocreatine and reduction of myocardial lactate and lactate/pyruvate ratio. Coadministration of A-12 and L-NAME aggravated recovery of coronary flow and cardiac function compared with these indices after A-12 treatment. Cardiac dysfunction was associated with increase in lactate dehydrogenase release in myocardial effluent, reduction of glucose oxidation and abolishment of augmented restoration of high energy phosphates. The results clearly demonstrate involvement of NOS-dependent mechanisms in cardioprotection afforded by apelin.
