Defective calcium handling in cardiomyocytes isolated from hearts subjected to ischemia-reperfusion

2005 ◽  
Vol 288 (5) ◽  
pp. H2260-H2270 ◽  
Author(s):  
Harjot K. Saini ◽  
Naranjan S. Dhalla
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Ischemia Reperfusion ◽  
Cardiac Performance ◽  
The Other ◽  
Calcium Handling ◽  
Subcellular Organelles ◽  
Rat Hearts ◽  
Intracellular Ca

Although ischemia-reperfusion (I/R) has been shown to affect subcellular organelles that regulate the intracellular Ca2+ concentration ([Ca2+]i), very little information regarding the Ca2+ handling ability of cardiomyocytes obtained from I/R hearts is available. To investigate changes in [Ca2+]i due to I/R, rat hearts in vitro were subjected to 10–30 min of ischemia followed by 5–30 min of reperfusion. Cardiomyocytes from these hearts were isolated and purified; [Ca2+]i was measured by employing fura-2 microfluorometry. Reperfusion for 30 min of the 20-min ischemic hearts showed attenuated cardiac performance, whereas basal [Ca2+]i as well as the KCl-induced increase in [Ca2+]i and isoproterenol (Iso)-induced increase in [Ca2+]i in cardiomyocytes remained unaltered. On the other hand, reperfusion of the 30-min ischemic hearts for different periods revealed marked changes in cardiac function, basal [Ca2+]i, and Iso-induced increase in [Ca2+]i without any alterations in the KCl-induced increase in [Ca2+]i or S(−)-BAY K 8644-induced increase in [Ca2+]i. The I/R-induced alterations in cardiac function, basal [Ca2+]i, and Iso-induced increase in [Ca2+]i in cardiomyocytes were attenuated by an antioxidant mixture containing superoxide dismutase and catalase as well as by ischemic preconditioning. The observed changes due to I/R were simulated in hearts perfused with H2O2 for 30 min. These results suggest that abnormalities in basal [Ca2+]i as well as mobilization of [Ca2+]i upon β-adrenoceptor stimulation in cardiomyocytes are dependent on the duration of ischemic injury to the myocardium. Furthermore, Ca2+ handling defects in cardiomyocytes appear to be mediated through oxidative stress in I/R hearts.

Ischemia–reperfusion-induced changes in sarcolemmal Na+/K+-ATPase are due to the activation of calpain in the heartThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.

2010 ◽  
Vol 88 (3) ◽  
pp. 388-397 ◽  
Author(s):  
Raja B. Singh ◽  
Naranjan S. Dhalla
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Atpase Activity ◽  
Protein Content ◽  
Ischemia Reperfusion ◽  
Specific Inhibitor ◽  
Calpain Activity ◽  
Rat Hearts ◽  
Intracellular Ca ◽  
Calpain Inhibitors

Depression in cardiac performance due to ischemia–reperfusion (I/R) injury is associated with the development of oxidative stress and decreased sarcolemmal (SL) Na+/K+-ATPase activity. Since both I/R and oxidative stress have been reported to promote the occurrence of intracellular Ca2+ overload and activate proteases such as calpain, this study was undertaken to investigate whether the activation of calpain in I/R hearts is associated with alterations in the SL Na+/K+-ATPase activity and its isoform content. For this purpose, isolated rat hearts treated with and without 2 different calpain inhibitors (leupeptin and MDL28170) were subjected to 30 min ischemia followed by 60 min of reperfusion, and the cardiac function, SL Na+/K+-ATPase activity, Na+/K+-ATPase isoform protein content, and calpain activity were measured. The I/R-induced depressions in cardiac function, Na+/K+-ATPase activity, and protein content of Na+/K+-ATPase isoforms were associated with an increase in calpain activity , but were prevented by treatment of hearts with leupeptin. Incubation of SL membranes with calpain decreased the Na+/K+-ATPase activity and protein content of its isoforms; these changes were also attenuated by leupeptin. The I/R-induced alterations in cardiac function and the activity of SL Na+/K+-ATPase and calpain were Ca2+-dependent and were prevented by MDL28170, a specific inhibitor of calpain. The I/R-induced translocation of calpain isoforms (I and II) from the cytosol to SL and the changes in distribution of calpastatin were also attenuated by treatment with calpain inhibitors. These results suggest that the depression in cardiac function and SL Na+/K+-ATPase activity in I/R hearts may be due to changes in the activity and translocation of calpain.

Activation of proteolytic enzymes and depression of the sarcolemmal Na+/K+-ATPase in ischemia–reperfused heart may be mediated through oxidative stress

2012 ◽  
Vol 90 (2) ◽  
pp. 249-260 ◽  
Author(s):  
Raja B. Singh ◽  
Larry Hryshko ◽  
Darren Freed ◽  
Naranjan S. Dhalla
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Atpase Activity ◽  
Proteolytic Enzymes ◽  
Ischemia Reperfusion ◽  
The Other ◽  
Calpain Activity ◽  
Rat Hearts ◽  
Induced Changes ◽  
Isolated Rat

We tested whether the activation of proteolytic enzymes, calpain, and matrix metalloproteinases (MMPs) during ischemia–reperfusion (I/R) is mediated through oxidative stress. For this purpose, isolated rat hearts were subjected to a 30 min global ischemia followed by a 30 min reperfusion. Cardiac function was monitored and the activities of Na+/K+-ATPase, Mg2+-ATPase, calpain, and MMP were measured. Depression of cardiac function and Na+/K+-ATPase activity in I/R hearts was associated with increased calpain and MMP activities. These alterations owing to I/R were similar to those observed in hearts perfused with hypoxic medium, H2O2 and xanthine plus xanthine oxidase. The I/R-induced changes were attenuated by ischemic preconditioning as well as by perfusing the hearts with N-acetylcysteine or mercaptopropionylglycine. Inhibition of MMP activity in hearts treated with doxycycline depressed the I/R-induced changes in cardiac function and Na+/K+-ATPase activity without affecting the calpain activation. On the other hand, inhibition of calpain activity upon treatment with leupeptin or MDL 28170 significantly reduced the MMP activity in addition to attenuating the I/R-induced alterations in cardiac function and Na+/K+-ATPase activity. These results suggest that the I/R-induced depression in Na+/K+-ATPase and cardiac function may be a consequence of the increased activities of both calpain and MMP because of oxidative stress in the heart.

scholarly journals Attenuation of extracellular ATP response in cardiomyocytes isolated from hearts subjected to ischemia-reperfusion

2005 ◽  
Vol 289 (2) ◽  
pp. H614-H623 ◽  
Author(s):  
Harjot K. Saini ◽  
Vijayan Elimban ◽  
Naranjan S. Dhalla
Keyword(s):  
Cardiac Function ◽  
Positive Inotropic Effect ◽  
Ischemia Reperfusion ◽  
Cardiac Contractility ◽  
Extracellular Atp ◽  
Binding Characteristics ◽  
Rat Hearts ◽  
The Status ◽  
Intracellular Ca ◽  
Isolated Rat

Extracellular ATP is known to augment cardiac contractility by increasing intracellular Ca2+ concentration ([Ca2+]i) in cardiomyocytes; however, the status of ATP-mediated Ca2+ mobilization in hearts undergoing ischemia-reperfusion (I/R) has not been examined previously. In this study, therefore, isolated rat hearts were subjected to 10–30 min of global ischemia and 30 min of reperfusion, and the effect of extracellular ATP on [Ca2+]i was measured in purified cardiomyocytes by fura-2 microfluorometry. Reperfusion for 30 min of 20-min ischemic hearts, unlike 10-min ischemic hearts, revealed a partial depression in cardiac function and ATP-induced increase in [Ca2+]i; no changes in basal [Ca2+]i were evident in 10- or 20-min I/R preparations. On the other hand, reperfusion of 30-min ischemic hearts for 5, 15, or 30 min showed a marked depression in both cardiac function and ATP-induced increase in [Ca2+]i and a dramatic increase in basal [Ca2+]i. The positive inotropic effect of extracellular ATP was attenuated, and the maximal binding characteristics of 35S-labeled adenosine 5′-[γ-thio]triphosphate with crude membranes from hearts undergoing I/R was decreased. ATP-induced increase in [Ca2+]i in cardiomyocytes was depressed by verapamil and Cibacron Blue in both control and I/R hearts; however, this response in I/R hearts, unlike control hearts, was not affected by ryanodine. I/R-induced alterations in cardiac function and ATP-induced increase in [Ca2+]i were attenuated by treatment with an antioxidant mixture and by ischemic preconditioning. The observed changes due to I/R were simulated in hearts perfused with H2O2. The results suggest an impairment of extracellular ATP-induced Ca2+ mobilization in I/R hearts, and this defect appears to be mediated through oxidative stress.

Modification of alterations in cardiac function and sarcoplasmic reticulum by vanadate in ischemic-reperfused rat hearts

2005 ◽  
Vol 99 (3) ◽  
pp. 999-1005 ◽  
Author(s):  
Satoshi Takeda ◽  
Seibu Mochizuki ◽  
Harjot K. Saini ◽  
Vijayan Elimban ◽  
Naranjan S. Dhalla
Keyword(s):  
Superoxide Dismutase ◽  
Sarcoplasmic Reticulum ◽  
Cardiac Function ◽  
Diastolic Pressure ◽  
Ischemia Reperfusion ◽  
Cardiac Performance ◽  
Sr Protein ◽  
Release Channel ◽  
Beneficial Effects ◽  
Rat Hearts

To study the cardioprotective effects of vanadate on ischemia-reperfusion (I/R) injury, isolated rat hearts perfused at constant flow were subjected to global ischemia for 30 min followed by reperfusion for 30 min. In this experimental model, I/R markedly decreased ventricular developed pressure and increased end-diastolic pressure. Pretreatment of hearts with 4 μM vanadate attenuated I/R-induced cardiac dysfunction. The reduction in sarcoplasmic reticulum (SR) Ca2+ uptake and Ca2+ release, as well as SR protein contents for Ca2+-pump ATPase and Ca2+-release channel, was also prevented by vanadate. Pretreatment of hearts with an antioxidant mixture containing superoxide dismutase + catalase exerted effects similar to those of vanadate in I/R hearts. Postischemic treatment of hearts with vanadate or superoxide dismutase + catalase also had beneficial effects on I/R-induced changes in cardiac performance and SR function. Alterations in cardiac function and SR Ca2+ transport due to an oxyradical-generating system (xanthine + xanthine oxidase) or an oxidant (H2O2) were attenuated by treatment with vanadate. These results suggest that vanadate may exert beneficial effects on cardiac performance and SR function in I/R hearts because of its antioxidant action.

Deglycosylated ceruloplasmin maintains its enzymatic, antioxidant, cardioprotective, and neuronoprotective properties

2001 ◽  
Vol 79 (4) ◽  
pp. 489-497 ◽  
Author(s):  
M'hammed Aouffen ◽  
Joanne Paquin ◽  
Eric De Grandpré ◽  
Réginald Nadeau ◽  
Mircea-Alexandru Mateescu
Keyword(s):  
Oxidative Stress ◽  
Genetic Engineering ◽  
Ischemia Reperfusion ◽  
Carbohydrate Moiety ◽  
Native Protein ◽  
Expression Systems ◽  
Protective Actions ◽  
Rat Hearts ◽  
Isolated Rat

Ceruloplasmin (CP), an important serum antioxidant, is a blue copper glycoprotein with ferroxidase and oxidase activities. Among other physiological actions, plasma CP was shown to protect isolated rat hearts and cultured P19 neurons exposed to oxidative stress conditions, raising the possibility of using this protein in the treatment of cardiac and neuronal diseases related to oxidative damage. However, since therapeutic applications of CP must be compatible with restrictions in the administration of blood derivatives to humans, there is a need to produce the protein by genetic engineering. To help in the choice of adequate expression systems, we undertook this study to determine if the carbohydrate moiety on the protein is essential for its functions. CP was completely deglycosylated using N-glycosidase F under nondenaturing conditions. Deglycosylated CP was found to retain most of the conformational, antioxidant, and enzymatic properties of the native protein in vitro. Moreover, both forms of the protein had similar cardioprotective and neuronoprotective effects against oxidative stress as evaluated with isolated rat hearts undergoing ischemia–reperfusion and with cultured P19 neurons exposed to xanthine – xanthine oxidase. The data thus indicate that the carbohydrate moiety of CP is not essential for its enzymatic and protective actions. Accordingly, even the use of expression systems that do not glycosylate mammalian proteins could provide a recombinant CP that retains its therapeutic potential.Key words: copperproteins, protein-linked carbohydrates, ischemia-reperfusion, isolated rat hearts, cultured P19 neurons.

scholarly journals Dexmedetomidine Protects against Myocardial Ischemia/Reperfusion Injury by Ameliorating Oxidative Stress and Cell Apoptosis through the Trx1-Dependent Akt Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhi-lin Wu ◽  
Jacques Robert Jeppe Davis ◽  
Yi Zhu
Keyword(s):  
Oxidative Stress ◽  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Cell Apoptosis ◽  
Ischemia Reperfusion ◽  
Cardioprotective Effect ◽  
Akt Pathway ◽  
Rat Hearts ◽  
Myocardial Ischemia Reperfusion ◽  
Isolated Rat

Dexmedetomidine (Dex) was reported to reduce oxidative stress and protect against myocardial Ischemia/Reperfusion (I/R) injury. However, the molecular mechanism involved in its antioxidant property is not fully elucidated. The present study was aimed at investigating whether the Trx1/Akt pathway participated in the cardioprotective effect of Dex. In the present study, I/R-induced myocardial injury in isolated rat hearts and OGD/R-induced injury in H9c2 cardiomyocytes were established. Our findings suggested that Dex ameliorated myocardial I/R injury by improving cardiac function, reducing myocardial apoptosis and oxidative stress, which was manifested by increased GSH and SOD contents, decreased ROS level, and MDA generation in both the isolated rat hearts and OGD/R-treated H9C2 cells. More importantly, it was found that the level of Trx1 was preserved, and Akt phosphorylation was significantly upregulated by Dex treatment. However, these effects of Dex were abolished by PX-12 (a specific Trx1 inhibitor) administration. Taken together, this study suggests that Dex plays a protective role in myocardial I/R injury, improves cardiac function, and relieves oxidative stress and cell apoptosis. Furthermore, our results present a novel signaling mechanism that the cardioprotective effect of Dex is at least partly achieved through the Trx1-dependent Akt pathway.

Expression of SERCA isoform with faster Ca2+ transport properties improves postischemic cardiac function and Ca2+ handling and decreases myocardial infarction

2007 ◽  
Vol 293 (4) ◽  
pp. H2418-H2428 ◽  
Author(s):  
M. A. Hassan Talukder ◽  
Anuradha Kalyanasundaram ◽  
Xue Zhao ◽  
Li Zuo ◽  
Poornima Bhupathy ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Myocardial Salvage ◽  
Myocardial Infarct Size ◽  
Intracellular Ca ◽  
Developed Pressure

Myocardial ischemia-reperfusion (I/R) injury is associated with contractile dysfunction, arrhythmias, and myocyte death. Intracellular Ca2+ overload with reduced activity of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a critical mechanism of this injury. Although upregulation of SERCA function is well documented to improve postischemic cardiac function, there are conflicting reports where pharmacological inhibition of SERCA improved postischemic function. SERCA2a is the primary cardiac isoform regulating intracellular Ca2+ homeostasis; however, SERCA1a has been shown to substitute SERCA2a with faster Ca2+ transport kinetics. Therefore, to further address this issue and to evaluate whether SERCA1a expression could improve postischemic cardiac function and myocardial salvage, in vitro and in vivo myocardial I/R studies were performed on SERCA1a transgenic (SERCA1a+/+) and nontransgenic (NTG) mice. Langendorff-perfused hearts were subjected to 30 min of global ischemia followed by reperfusion. Baseline preischemic coronary flow and left ventricular developed pressure were significantly greater in SERCA1a+/+ mice compared with NTG mice. Independent of reperfusion-induced oxidative stress, SERCA1a+/+ hearts demonstrated greatly improved postischemic (45 min) contractile recovery with less persistent arrhythmias compared with NTG hearts. Morphometry showed better-preserved myocardial structure with less infarction, and electron microscopy demonstrated better-preserved myofibrillar and mitochondrial ultrastructure in SERCA1a+/+ hearts. Importantly, intraischemic Ca2+ levels were significantly lower in SERCA1a+/+ hearts. The cardioprotective effect of SERCA1a was also observed during in vivo regional I/R with reduced myocardial infarct size after 24 h of reperfusion. Thus SERCA1a+/+ hearts were markedly protected against I/R injury, suggesting that expression of SERCA 1a isoform reduces postischemic Ca2+ overload and thus provides potent myocardial protection.

scholarly journals Dihydromyricetin Ameliorates Cardiac Ischemia/Reperfusion Injury through Sirt3 Activation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Liping Wei ◽  
Xuseng Sun ◽  
Xin Qi ◽  
Yufan Zhang ◽  
Yuanyang Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Reperfusion Injury ◽  
Mitochondrial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
In Vitro Study ◽  
Vitro Study ◽  
Ampelopsis Grossedentata

During myocardial infarction, quickly opening the occluded coronary artery is a major method to save the ischemic myocardium. However, it also induces reperfusion injury, resulting in a poor prognosis. Alleviating the reperfusion injury improves the prognosis of the patients. Dihydromyricetin (DHM), a major component in the Ampelopsis grossedentata, has numerous biological functions. This study aims to clarify the effects of DHM under the ischemia/reperfusion (I/R) condition. We elucidated the role of Sirt3 in the cardiomyocyte response to DHM based on the hearts and primary cardiomyocytes. Cardiac function, mitochondrial biogenesis, and infarct areas were examined in the different groups. We performed Western blotting to detect protein expression levels after treatments. In an in vitro study, primary cardiomyocytes were treated with Hypoxia/Reoxygenation (H/R) to simulate the I/R. DHM reduced the infarct area and improved cardiac function. Furthermore, mitochondrial dysfunction was alleviated after DHM treatment. Moreover, DHM alleviated oxidative stress indicated by decreased ROS and MnSOD. However, the beneficial function of DHM was abolished after removing the Sirt3. On the other hand, the mitochondrial function was improved after DHM intervention in vitro study. Interestingly, Sirt3 downregulation inhibited the beneficial function of DHM. Therefore, the advantages of DHM are involved in the improvement of mitochondrial function and decreased oxidative stress through the upregulation of Sirt3. DHM offers a promising therapeutic avenue for better outcome in the patients with cardiac I/R injury.

Hemoglobin Vesicle Improves Recovery of Cardiac Function After Ischemia–Reperfusion by Attenuating Oxidative Stress in Isolated Rat Hearts

2011 ◽  
Vol 58 (5) ◽  
pp. 528-534
Author(s):  
Jun Nakajima ◽  
Motoaki Bessho ◽  
Takeshi Adachi ◽  
Tadashi Yamagishi ◽  
Shinichi Tokuno ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cardiac Function ◽  
Ischemia Reperfusion ◽  
Rat Hearts ◽  
Isolated Rat

Attenuation of ischemia–reperfusion-induced alterations in intracellular Ca2+ in cardiomyocytes from hearts treated with N-acetylcysteine and N-mercaptopropionylglycineThis article is one of a selection of papers published in a special issue on Advances in Cardiovascular Research.

2009 ◽  
Vol 87 (12) ◽  
pp. 1110-1119 ◽  
Author(s):  
Harjot K. Saini-Chohan ◽  
Naranjan S. Dhalla
Keyword(s):  
Oxidative Stress ◽  
Diastolic Pressure ◽  
Ischemia Reperfusion ◽  
Redox Status ◽  
Left Ventricular ◽  
Cardiovascular Research ◽  
Rat Hearts ◽  
Intracellular Ca ◽  
Developed Pressure ◽  
Selection Of

This study was undertaken to test whether Ca2+-handling abnormalities in cardiomyocytes after ischemia–reperfusion (I/R) are prevented by antioxidants such as N-acetyl l-cysteine (NAC), which is known to reduce oxidative stress by increasing the glutathione redox status, and N-(2-mercaptopropionyl)-glycine (MPG), which scavenges both peroxynitrite and hydroxyl radicals. For this purpose, isolated rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion, and cardiomyocytes were prepared to monitor changes in the intracellular concentration of free Ca2+ ([Ca2+]i). Marked depression in the left ventricular developed pressure and elevation in the left ventricular end-diastolic pressure in I/R hearts were attenuated by treatment with NAC or MPG. Cardiomyocytes obtained from I/R hearts showed an increase in the basal level of [Ca2+]i as well as augmentation of the low Na+-induced increase in [Ca2+]i, with no change in the KCl-induced increase in [Ca2+]i. These I/R-induced alterations in Ca2+ handling by cardiomyocytes were attenuated by treatment of hearts with NAC or MPG. Furthermore, reduction in the isoproterenol-, ATP-, ouabain-, and caffeine-induced increases in [Ca2+]i in cardiomyocytes from I/R hearts were limited by treatment with NAC or MPG. The increases in the basal [Ca2+]i, unlike the KCl-induced increase in [Ca2+]i, were fully or partially prevented by both NAC and MPG upon exposing cardiomyocytes to hypoxia–reoxygenation, H2O2, or a mixture of xanthine and xanthine oxidase. These results suggest that improvement in cardiac function of I/R hearts treated with NAC or MPG was associated with attenuation of changes in Ca2+ handling by cardiomyocytes, and the results support the view that oxidative stress due to oxyradical generation and peroxynitrite formation plays an important role in the development of intracellular Ca2+ overload in cardiomyocytes as a consequence of I/R injury.

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