Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of the present study was to determine if repetitive myocardial ischemia would result in the cumulative loss of mitochondrial adenine nucleotides. Isolated perfused rat hearts were subjected to continuous or intermittent ischemia. A single 5-minute period of continuous ischemia did not result in a significant decrease in the mitochondrial adenine nucleotide pool; a single 10-minute period of ischemia resulted in a decrease of approximately 17%. Next, the adenine nucleotide content of mitochondria from preischemic and 30-minute continuous ischemic hearts was compared with two groups of hearts undergoing intermittent ischemia (both groups receiving a total of 30 minutes of ischemia). One group received three 10-minute episodes of ischemia interrupted by 5-minute periods of reperfusion (3 x 10-minute intermittent ischemia); the other intermittent ischemic group received six 5-minute episodes of ischemia interrupted by 5-minute periods of perfusion (6 x 5-minute intermittent ischemia). The mitochondrial adenine nucleotide content (expressed as nanomoles per nanomole cytochrome a) for the preischemic and 30-minute continuous ischemic hearts was 14.7 +/- 0.6 and 8.0 +/- 0.4, respectively. The mitochondrial adenine nucleotide content of the 3 x 10-minute intermittent ischemia group (8.5 +/- 0.5) was not significantly different from the 30-minute continuous ischemic group. The mitochondrial adenine nucleotide content of the 6 x 5-minute intermittent ischemia group (11.0 +/- 0.6) was significantly larger than that of the 30-minute continuous and the 3 x 10-minute intermittent ischemia groups (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intermittent ischemia produces a cumulative depletion of mitochondrial adenine nucleotides in the isolated perfused rat heart. 229 5

The article deals with the effect of permanent, temporal and total myocardial ischemia on the oxidation of acetate, hexanoate, palmitoylcarnitine and palmitoyl-CoA in isolated rabbit heart mitochondria. All the three models of ischemia in different experimental situations demonstrated a similar degree of fatty acid oxidation suppression independent of the length of acyl residue, the suppression being the greatest during the first hours and in total ischemia. Both in the control and in ischemia, respiratory activity was at its highest level with acetate, decreasing in the order above. Thus, the rate of Krebs' cycle reactions and of respiratory chain does not limit medium- and long-chain fatty acid oxidation. It is nevertheless established that suppression of their oxidation in ischemia is completely determined by the decrease of cytochrome S and of endogenous substrate intermediates of Krebs' cycle in the mitochondria; decreased adenine nucleotide and carnitine-palmitoyl-transferase transport (other authors' data) is not critical, at least in early ischemia (0.5 h). Ischemic mitochondria are characterized by incomplete palmitoylcarnitine oxidation.
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PMID:[Mechanism of ischemic disorders of fatty acid oxidation in heart mitochondria]. 298 85

Differential cytochrome spectra and their fourth degree derivatives were recorded at 77 degrees K temperature. During myocardial ischemia (2-h autolysis), only cytochrome c content was found to be decreased in isolated mitochondria. According to these data mitochondrial state 3 respiration with succinate decreased only in a medium without cytochrome c. Before ADP addition mitochondrial respiration increased but in a medium with cytochrome c. This was followed by an increase in the respiration rate minimized by bromthymole blue, an inhibitor of dicarboxylate transport. It is inferred that these alterations seen in ischemia are linked with increased permeability of mitochondrial membranes: external for cytochrome c, and internal for inorganic ions and low-molecular compounds.
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PMID:[Changes in the quantitative composition of cytochromes and the functional activity of heart mitochondria during ischemia]. 631 61

The effect of fructose-1, 6-diphosphate (200 mg/kg), cytochrome C (20 mg/kg) and their combinations on the size of the zone of necrosis 4 and 72 h after 15-min transitory myocardial ischemia was studied. Combination of the compounds under study inhibited considerably the development of post-occlusion and reperfusion arrhythmias and reduced the size of necrosis 4 h after their administration as prophylactic and arresting measures (to 23.8 +/- 2.9 and 29.3 +/- 3.6% of the ischemic zone, respectively, in 42.8 +/- 3.8% in the control). A combined course of cytochrome C and fructose diphosphate also limited the size of the necrotic zone 72 h after transitory ischemia. Separate single administration of fructose diphosphate and cytochrome C caused no essential changes in the size of myocardial necrosis recorded 72 h after transitory myocardial ischemia.
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PMID:[The effect of fructose-1,6-diphosphate, cytochrome c and their combination on the size of the necrotic area in transient myocardial ischemia]. 916 79

Besides necrosis, apoptosis is the other major mode of cardiomyocyte loss in ischemic cardiovascular disease. In the present study, we examined the hypothesis that nitric oxide (NO) protects myocardial function by improving myocardial microcirculation and attenuating cardiomyocyte apoptosis in a rat model of myocardial ischemia/reperfusion (MI/R). The left main coronary artery of anesthetized male rats was ligated for 40 min, followed by 4 h reperfusion. Four groups of animals were studied: sham operated control + saline; sham operated control + N(W)-nitro-L-arginine methyl ester (L-NAME); MI/R + saline; MI/R + L-NAME (10 mg/kg, iv, 10 min prior to reperfusion). Results show that MI/R caused a decrease in mean arterial blood pressure (MABP), cardiac index (CI), and stroke volume index (SVI). Inhibition of NO synthesis by L-NAME attenuated plasma NO levels, but increased MABP and SVR in sham control rats and rats subjected to MI/R, and further depressed left ventricular function in rats subjected to MI/R as indicated by decreased CI and SVI. Furthermore, administration of L-NAME to rats subjected to MI/R enhanced cardiomyocyte apoptosis as indicated by a significant increase in DNA fragmentation compared to rats with MI/R alone. Histological study revealed that L-NAME caused arterial constriction and congestion of red blood cells in arteries and capillaries in the peri-ischemic areas of the hearts in rats subjected to MI/R and, interestingly, also in the sham control rats. Data suggest that the mechanism of increased reperfusion injury may be attributable to a "no-reflow" phenomenon induced by L-NAME, resulting in increased cardiomyocyte apoptosis secondary to ischemia and enhanced cytochrome-c release from mitochondria. In addition, cardiac injury may be increased due to the augmented oxygen consumption of cardiomyocytes caused by the increased SVR and afterload. These results suggest that endogenous NO may act to improve myocardial microvascular perfusion, reduce SVR, and limit cardiomyocyte apoptosis, thereby, attenuating myocardial dysfunction induced by MI/R.
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PMID:L-NAME enhances microcirculatory congestion and cardiomyocyte apoptosis during myocardial ischemia-reperfusion in rats. 1190 Mar 36

The heart constitutively expresses heme oxygenase (HO)-2, which catabolizes heme-containing proteins to produce biliverdin and carbon monoxide (CO). The heart also contains many possible substrates for HO-2 such as heme groups of myoglobin and cytochrome P-450s, which potentially could be metabolized into CO. As a result of observations that CO activates guanylyl cyclase and induces vascular relaxation and that HO appears to confer protection from ischemic injury, we hypothesized that the HO-CO pathway is involved in ischemic vasodilation in the coronary microcirculation. Responses of epicardial coronary arterioles to ischemia (perfusion pressure approximately 40 mmHg; flow velocity decreased by approximately 50%; dL/dt reduced by approximately 60%) were measured using stroboscopic fluorescence microangiography in 34 open-chest anesthetized dogs. Ischemia caused vasodilation of coronary arterioles by 36 +/- 6%. Administration of N(G)-monomethyl-L-arginine (L-NMMA, 3 micromol.kg(-1).min(-1) intracoronary), indomethacin (10 mg/kg iv), and K(+) (60 mM, epicardial suffusion) to prevent the actions of nitric oxide, prostaglandins, and hyperpolarizing factors, respectively, partially inhibited dilation during ischemia (36 +/- 6 vs. 15 +/- 4%; P < 0.05). The residual vasodilation during ischemia after antagonist administration was inhibited by tin mesoporphyrin IX (SnMP, 10 mg/kg iv), which is an inhibitor of HO (15 +/- 4 vs. 7 +/- 2%; P < 0.05 vs. before SnMP). The guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (10(-5) M, epicardial suffusion) also inhibited vasodilation during ischemia in the presence of L-NMMA with indomethacin and KCl. Moreover, administration of heme-L-arginate, which is a substrate for HO, produced dilation after ischemia but not after control conditions. We conclude that during myocardial ischemia, HO-2 activation can produce cGMP-mediated vasodilation presumably via the production of CO. This vasodilatory pathway appears to play a backup role and is activated only when other mechanisms of vasodilation during ischemia are exhausted.
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PMID:In vivo role of heme oxygenase in ischemic coronary vasodilation. 1514 58

Early contractile dysfunction and the later death of cardiomyocytes are two major problems that can follow myocardial infarction or major cardiovascular surgery that demands ischemic arrest of the heart. Here, we found that 24 h of hypoxia and 1 h of reoxygenation induced the expression of the chaperone ORP150 in cultured rat cardiomyocytes. Inhibition of its induction using an adenovirus to express anti-sense ORP150 significantly enhanced the hypoxia-reoxygenation-induced cardiomyocyte death; cell death was reduced by overexpressing ORP150. Decreased levels of ORP150 expression also enhanced caspase-3 and -8 activation, cytochrome-c release, and DNA fragmentation, suggesting that this chaperone regulates apoptotic cell death. In contrast, increasing the expression of ORP150 in the cardiomyocytes had the opposite effect on the expression of these molecules. Moreover, apoptotic cell death initiated by myocardial ischemia-reperfusion (I/R) was significantly inhibited in vivo by transfecting an ORP150 expression plasmid into whole rat heart using the hemagglutinating virus of Japan (HVJ)-liposome method. Interestingly, ORP150 seemed to preserve calcium homeostasis in cardiomyocytes that underwent ischemia-reoxygenation in vitro. Calpain activity in the cardiomyocytes was enhanced by anti-sense ORP150 and suppressed by sense ORP150. Finally, we examined the functional recovery of rat hearts that overexpressed ORP150 or GFP protein and were subjected to I/R; we found that ORP150 preserved early contractile function after transient ischemia. Our results indicated cytoprotective roles for ORP150 in rat heart and suggested a therapeutic role for the protein both in preventing cardiomyocyte death and in preserving contractile function after ischemic damage.
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PMID:150-kDa oxygen-regulated protein attenuates myocardial ischemia-reperfusion injury in rat heart. 1573 11

Hypoxia and hypoxia-reperfusion (H-R) play important roles in human pathophysiology because they occur in clinical conditions such as circulatory shock, myocardial ischemia, stroke, and organ transplantation. Reintroduction of oxygen to hypoxic cells during reperfusion causes an increase in generation of reactive oxygen species (ROS), which can alter cell signaling, and cause damage to lipids, proteins, and DNA leading to ischemia-reperfusion injury. Since vitamin C is a potent antioxidant and quenches ROS, we investigated the role of intracellular ascorbic acid (iAA) in endothelial cells undergoing hypoxia-reperfusion. Intracellular AA protected human endothelial cells from H-R-induced apoptosis. Intracellular AA also prevents loss of mitochondrial membrane potential and the release of cytochrome C and activation of caspase-9 and caspase-3 during H-R. Additionally, inhibition of caspase-9 activation prevented H-R-induced apoptosis, suggesting a mitochondrial site of initiation of apoptosis. We found that H-R induced an increase in ROS in endothelial cells that was abrogated in the presence of iAA. Our results indicate that vitamin C prevents hypoxia and H-R-induced damage to human endothelium.
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PMID:Hypoxia-reoxygenation-induced mitochondrial damage and apoptosis in human endothelial cells are inhibited by vitamin C. 1585 49

Clopidogrel and statins are frequently administered in patients with ischemic heart disease or other atherothrombotic manifestations and are effective in the prevention of cardiovascular disease. The thienopyridine clopidogrel is a pro-drug metabolised in the liver via the cytochrome P450 (CYP) 3A4 system to the active compound which inhibits the P2Y(12) ADP platelet receptor. The assumption exists that the effect of clopidogrel in inhibiting platelet aggregation is attenuated by co-administration of lipophilic statins such as atorvastatin or simvastatin which are metabolised by the CYP3A4 system to inactive substrates. Assessing a possible drug-drug interaction ex-vivo, inconclusive studies have been published: In an aggregometer study, a strong and dose-dependent interference between atorvastatin and the inhibitory effect of clopidogrel on platelet function was observed. Another study, measuring the effect of clopidogrel by flow cytometry, found a significant attenuation of the clopidogrel effect by lipophilic statins, predominantly in the loading phase. In contrast a recent study, which used 600 mg clopidogrel for loading, found no significant interference between various statins and clopidogrel on ADP-induced platelet aggregation and in addition another study revealed no attenuation of the clopidogrel effect despite statin co-medication after 5 weeks. Additionally, retrospective analysis of clinical studies (CREDO-study) or registries (MITRA-PLUS) revealed no significant influence of different statins on the clinical outcome in patients treated with clopidogrel. However, these clinical studies showed a trend towards a diminishing effect of clopidogrel on those treated with cytochrome CYP3A4 metabolised statins. Even more important seems to be the considerable variability in the response of the antiplatelet effect of clopidogrel. A certain percentage of patients apparently do not respond adequately to clopidogrel treatment. This effect of clopidogrel resistance seems to be more important as the potential interference between CYP3A4 metabolized statins and clopidogrel. Finally, up until now sufficient evidence has not been gained to prefer hydrophil statins on patients receiving clopidogrel co-medication or when to discontinue the use of statins in clopidogrel treatment. Prospective studies are necessary in order to evaluate the magnitude of clopidogrel resistance and the impact of clopidogrel co-medication as well as to redefine antithrombotic therapy for this subgroup.
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PMID:Thienopyridines and statins: assessing a potential drug-drug interaction. 1661 Nov 11

The cytochrome p450 2C (CYP2C) monooxygenase family is a key player in the generation of epoxyeicosatrienoic acids. It has recently become apparent that CYP plays an important role in cardiovascular physiology and contributes to the pathogenesis of various cardiovascular diseases. In particular, several studies have demonstrated a role for these enzymes in cardiac ischemia and reperfusion injury. The current review summarizes the role of the CYP epoxygenase, CYP2C9, in ischemic heart disease and vascular homeostasis.
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PMID:Cytochrome p450 2C (CYP2C) in ischemic heart injury and vascular dysfunction. 1684 86


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