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Effect of preconditioning with single brief ischemia on myocardial energy metabolism of reperfused ischemic rat hearts
J Mol Cell Cardiol
23 (Supplement
II) (1991)
64 ALTERED METABOLIC RESPONSEOF REPERFUSEDNYOCARDIUMTO SUBSEQUENTBRIEF ISCHEMIA : DEPRESSEDMETABOLIC VIABILITY MAY BE INVOLVED AS THE BASIS OF PRECONDITIONING Y.Kimura, T.Saito, T.Abe, K.Takahashi, E.Fushimi, Y.Kudo and M.Miura. The 2nd Department of Internal Mdicine, Akita University, Akita, Japan. To evaluate the metabolic viability in reperfused myocardium, myocardial tissue PC0 and pH were simultaneously measured by FET-sensors in LV wall perfused by the left anterior descending coronary artery (LAD) with regional myocardial function. Protocol was as follows; LAD was occluded for Zmin(Tria1 l:Tr-1). followed by 15min of reperfusion. After that, in control group(Gr-C) reperfusion was continued for another 95min. while in others 5min(Cr-5) or 15min(Gr-15) of LAD occlusion followed by 90min or 80min of reperfusion was introduced. Then, LAD was again occluded for in Cr-C, there was no significant differ2min(Tr-2) in all groups. As the results; ence between Tr-1 and Tr-2, whereas myocardial production of CO and proton during Tr-2 was significantly diminished in Gr-5 and Gr-15 as previously reported. Histochemical study revealed a loss of glycogen staining in the reperfused area in both groups. CO and proton are the end-products of cardiac metabolism, so our results indicates that metabolic viability in reperfused myocardium was depressed (metabolic indicating inability to utilize the substrate of anerobic energy metabostunning), lism, glycogen during ischemia and that phenomenon might partly contribute to preconditioning effect.
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EFFECT OF PRECONDITIONING WITH SINGLE BRIEF ISCHEMIA ON MYOCARDIAL ENERGY METABOLISM OF REPERFUSED ISCHEMIC RAT HEARTS. T.Nakanishi, M.Nakagawa, Y.Abe*, H.Matsuoka. Y.Ono*', M.Miura. The 2nd Department of Internal Medicine, Akita University, Akita Medical Center*, Research Institute of Brain and Blood Vessels-Akita", Akita, Japan. This study was designed to investigate whether single brief ischemia produces the preconditioning effect on cardiac function, reperfusion arrhythmia and myocardial energy metabolism or not in the isolated reperfused ischemic working rat hearts. 30min occlusion of left coronary artery(LCA) followed by 3Omin reperfusion was perfomed with preceeding single 5min occlusion of LCA followed by 20min reperfusion in a preconditioning group(Cr-P), and without in a control group(Gr-C). Cardiac function was evaluated as rate pressure product(RPP), cardiac output(C0) and coronary myocardial ATP and creatine phosphate(CP) contents flow(CF). At the end of experiment, of reperfused ischemic myocardium were measured. RPP and CF were similar in both difference groups, but CO in Gr-P was higher than Gr-C. There was no significant in myocardial ATP contents between both groups, but CP content in Gr-P was significantly preserved than Gr-C. Incidences of ventricular fibrillation(Vf) were similar in both groups. Duration of Vf in Gr-P was shorter than Gr-C, but this difference was not significant. These results suggest that even single brief ischemia produces the preconditioning effect on cardiac function and myocardial energy metabolism in isolated reperfused ischemic rat heart.
MYOCARDIAL INFARCT SIZE LIMITAION BY PRECONDITIONING;ITS NATURAL DECAY AND "DOSE-RESPONSE" Tetsuji Mlura, Takeo Adachi, Takashi Ogawa, Toshihlro Iwamoto, Akihito Tsuchida, RELATION. Second Dept. of Internal Medicine, Sapporo Medical College, Japan Osamu Iimura. This study aimed to characterize the natural history of PC effect and the relation In addition, between the number of PC procedures and their effect. the time course of myocardial stunning of the preconditioned myocardium was analyzed to examine the role of artery of the rabbit was occluded for 30 min stunning in the mechanism of PC. The coronary and reperfused for 72 h with ox without PC with 5 min ischemia and various recovery In another group of rabbits, regional systolic thickening fraction (reperfusion) periods. Histological infarct size (IS) as % of (TF) was assessed by an epicardial Doppler sensor. area at risk (%IS/AB) was 43.9*5.0% (mean*SE) in the unpreconditioned group, and PC with 5 min ischemia/5 min reperfusion significantly limited %IS/AR to 19.3f3.5%. As the duration of recovery time between the PC and the 30 min coronary occlusion was prolonged, myocardial mass salvaged by PC was gradually diminished, and the IS limitation was not significant when 25 min or longer elapsed after the PC. On the other hand, TF after 5 min ischemia/5 min reperfusion was reduced to 64.9f8.9% of baseline and did not recovered for 30 min. which indicated the dissociation between the time course of PC protection and that of myocardial The %IS/AR after two and four cycles of PC with 5 min ischemia/5 min reperfusion stunning. These findings suggest that the ISwas similar to %IS/AR after an single 5 min PC episode. of PC did not limiting effect of PC with 5 min ischemia decays over 30 min. that repetition and that myocardial stunning is unlikely to contribute enhance its cardioprotective effect, to IS limitation by PC.
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23 (Supplement
II) (1991)
64 ALTERED METABOLIC RESPONSEOF REPERFUSEDNYOCARDIUMTO SUBSEQUENTBRIEF ISCHEMIA : DEPRESSEDMETABOLIC VIABILITY MAY BE INVOLVED AS THE BASIS OF PRECONDITIONING Y.Kimura, T.Saito, T.Abe, K.Takahashi, E.Fushimi, Y.Kudo and M.Miura. The 2nd Department of Internal Mdicine, Akita University, Akita, Japan. To evaluate the metabolic viability in reperfused myocardium, myocardial tissue PC0 and pH were simultaneously measured by FET-sensors in LV wall perfused by the left anterior descending coronary artery (LAD) with regional myocardial function. Protocol was as follows; LAD was occluded for Zmin(Tria1 l:Tr-1). followed by 15min of reperfusion. After that, in control group(Gr-C) reperfusion was continued for another 95min. while in others 5min(Cr-5) or 15min(Gr-15) of LAD occlusion followed by 90min or 80min of reperfusion was introduced. Then, LAD was again occluded for in Cr-C, there was no significant differ2min(Tr-2) in all groups. As the results; ence between Tr-1 and Tr-2, whereas myocardial production of CO and proton during Tr-2 was significantly diminished in Gr-5 and Gr-15 as previously reported. Histochemical study revealed a loss of glycogen staining in the reperfused area in both groups. CO and proton are the end-products of cardiac metabolism, so our results indicates that metabolic viability in reperfused myocardium was depressed (metabolic indicating inability to utilize the substrate of anerobic energy metabostunning), lism, glycogen during ischemia and that phenomenon might partly contribute to preconditioning effect.
65
66
EFFECT OF PRECONDITIONING WITH SINGLE BRIEF ISCHEMIA ON MYOCARDIAL ENERGY METABOLISM OF REPERFUSED ISCHEMIC RAT HEARTS. T.Nakanishi, M.Nakagawa, Y.Abe*, H.Matsuoka. Y.Ono*', M.Miura. The 2nd Department of Internal Medicine, Akita University, Akita Medical Center*, Research Institute of Brain and Blood Vessels-Akita", Akita, Japan. This study was designed to investigate whether single brief ischemia produces the preconditioning effect on cardiac function, reperfusion arrhythmia and myocardial energy metabolism or not in the isolated reperfused ischemic working rat hearts. 30min occlusion of left coronary artery(LCA) followed by 3Omin reperfusion was perfomed with preceeding single 5min occlusion of LCA followed by 20min reperfusion in a preconditioning group(Cr-P), and without in a control group(Gr-C). Cardiac function was evaluated as rate pressure product(RPP), cardiac output(C0) and coronary myocardial ATP and creatine phosphate(CP) contents flow(CF). At the end of experiment, of reperfused ischemic myocardium were measured. RPP and CF were similar in both difference groups, but CO in Gr-P was higher than Gr-C. There was no significant in myocardial ATP contents between both groups, but CP content in Gr-P was significantly preserved than Gr-C. Incidences of ventricular fibrillation(Vf) were similar in both groups. Duration of Vf in Gr-P was shorter than Gr-C, but this difference was not significant. These results suggest that even single brief ischemia produces the preconditioning effect on cardiac function and myocardial energy metabolism in isolated reperfused ischemic rat heart.
MYOCARDIAL INFARCT SIZE LIMITAION BY PRECONDITIONING;ITS NATURAL DECAY AND "DOSE-RESPONSE" Tetsuji Mlura, Takeo Adachi, Takashi Ogawa, Toshihlro Iwamoto, Akihito Tsuchida, RELATION. Second Dept. of Internal Medicine, Sapporo Medical College, Japan Osamu Iimura. This study aimed to characterize the natural history of PC effect and the relation In addition, between the number of PC procedures and their effect. the time course of myocardial stunning of the preconditioned myocardium was analyzed to examine the role of artery of the rabbit was occluded for 30 min stunning in the mechanism of PC. The coronary and reperfused for 72 h with ox without PC with 5 min ischemia and various recovery In another group of rabbits, regional systolic thickening fraction (reperfusion) periods. Histological infarct size (IS) as % of (TF) was assessed by an epicardial Doppler sensor. area at risk (%IS/AB) was 43.9*5.0% (mean*SE) in the unpreconditioned group, and PC with 5 min ischemia/5 min reperfusion significantly limited %IS/AR to 19.3f3.5%. As the duration of recovery time between the PC and the 30 min coronary occlusion was prolonged, myocardial mass salvaged by PC was gradually diminished, and the IS limitation was not significant when 25 min or longer elapsed after the PC. On the other hand, TF after 5 min ischemia/5 min reperfusion was reduced to 64.9f8.9% of baseline and did not recovered for 30 min. which indicated the dissociation between the time course of PC protection and that of myocardial The %IS/AR after two and four cycles of PC with 5 min ischemia/5 min reperfusion stunning. These findings suggest that the ISwas similar to %IS/AR after an single 5 min PC episode. of PC did not limiting effect of PC with 5 min ischemia decays over 30 min. that repetition and that myocardial stunning is unlikely to contribute enhance its cardioprotective effect, to IS limitation by PC.
S.38