Chronic Alcohol Intake Exacerbates Cardiac Dysfunction After Myocardial Infarction

2020 ◽  
Vol 55 (5) ◽  
pp. 524-530
Author(s):  
Yu Liang ◽  
Xuewen Xu ◽  
Qin Li ◽  
Yan Deng ◽  
Maodi Xie ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Drinking Water ◽  
Mitochondrial Function ◽  
Cardiac Dysfunction ◽  
Alcohol Intake ◽  
Alcohol Exposure ◽  
Heart Weight ◽  
Vehicle Group ◽  
Coronary Artery Ligation ◽  
Chronic Alcohol

Abstract Aims Alcohol intake is a risk factor for cardiovascular diseases. This study was designed to investigate whether chronic alcohol intake affects myocardial infarction (MI)-induced cardiac remodeling and heart failure. Methods Eight-week-old male C57BL/6 mice were randomly divided into four groups: Sham group (Sham), MI plus drinking water group (MI + Vehicle), and MI plus daily alcohol intake for 6 weeks with or without gavage of additional alcohol every 3 days (MI + Alcohol and MI + Alcohol + G). The MI were induced by permanent left anterior descending (LAD) coronary artery ligation surgery before vehicle or alcohol treatment. The blood alcohol concentration (BAC), cardiac function, release of cardiac enzymes, pathological changes and mitochondrial function were measured. Results As expected, supplementation of alcohol in drinking water significantly increased random BAC in mice. Long-term exposure to alcohol further reduced body weight, ejection fraction and fractional shortening in comparison with the MI + Vehicle group. Histopathological data showed that alcohol increased fibrosis in infarct zone, which was well correlated with the functional decline. Also, as compared to the MI + Vehicle group, the adenosine diphosphate-supported respiratory function of freshly isolated cardiac mitochondria was inhibited in the MI + Alcohol + G group. Besides, upon MI-induced cardiac damage, we did not observe further changes in heart weight, cardiomyocyte enlargement in remote zone, exercise capacity, lung edema and the release of cardiac enzyme after chronic alcohol intake. Conclusions Our study demonstrated that chronic daily alcohol exposure exacerbated MI-induced cardiac dysfunction, which is related to promoted myocardial fibrosis and inhibited mitochondrial function.

Abstract 11983: Auraptene, a Coumaric Compounds Analogous, Improved the Worsening of Systolic Function by Activating Mitochondrial Function After Myocardial Infarction in Rats

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yoichi Sunagawa ◽  
Miho Suzuki ◽  
Masafumi Funamoto ◽  
Yasufumi Katanasaka ◽  
Hidetoshi Suzuki ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Lipid Metabolism ◽  
Mitochondrial Function ◽  
Low Dose ◽  
Systolic Function ◽  
Pharmacological Therapy ◽  
Vehicle Group ◽  
High Dose ◽  
Related Gene

Introduction: Heart failure is associated with pathological growth and mitochondrial dysfunction of constituent cardiomyocytes. To achieve effective oral pharmacological therapy for heart failure, we screened compounds isolated from natural products and found that auraptene derived from the peel of Citrus Hassaku may be applicable to pharmacological therapy for heart failure. Hypothesis: We assessed the hypothesis that auraptene could improve the deterioration of mitochondrial function and the development of heart failure in rats with myocardial infarction (MI). Methods and Results: In cultured cardiomyocytes, auraptene (2.5-10 μM) dose-dependently repressed phenylephrine-induced hypertrophic responses such as increase in cell size and ANF and ET-1 promoter activations. Auraptene also activated mitochondrial- and lipid metabolism-related gene transcriptions, such as PGC1α, PPARα/γ, mCPT1, UCP3, and PDK4. One week after operation, 22 rats with a moderate size of MI (Fractional shortening (FS) < 40%) were then randomly assigned to vehicle (n=8), auraptene low-dose (5 mg/kg/day, n=7), or high-dose (50 mg/kg/day, n=7). Oral daily treatments with these agents were continued for 6 weeks. There were no differences in left ventricle (LV) geometric and functional data among the 3 MI groups before treatment. After treatment, LVFS was significantly higher in the auraptene low-dose (21%, p < 0.0001) and high-dose (26%, p < 0.0001) groups than the vehicle group (16%). LV wall thickness in the remote non-infarct area was significantly thinner in the auraptene low-dose (1.4 mm, p < 0.01) and high-dose (1.2 mm, p < 0.0001) groups than the vehicle group (2.5 mm). Histological analysis demonstrated that auraptene treatment significantly suppressed MI-induced increases in myocardial cell diameter and perivascular fibrosis compared with vehicle treatment. Moreover, auraptene also prevented the activations of ANF and MCP-1 mRNA levels and up-regulated mitochondrial- and lipid metabolism-related gene transcriptions in LV. Conclusions: Auraptene treatment prevents the worsening of LV systolic function and represses hypertrophy after MI in adult rats. A natural compound, auraptene is expected as a novel useful agent for heart failure therapy in humans.

Inhibition and reversal of myocardial infarction-induced hypertrophy and heart failure by NHE-1 inhibition

2004 ◽  
Vol 286 (1) ◽  
pp. H381-H387 ◽  
Author(s):  
Ling Chen ◽  
Chang Xun Chen ◽  
Xiaohong Tracey Gan ◽  
Norbert Beier ◽  
Wolfgang Scholz ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Infarct Size ◽  
Treatment Delay ◽  
Left Ventricular ◽  
Heart Weight ◽  
Coronary Artery Ligation ◽  
Treatment Protocols ◽  
Beneficial Effects ◽  
All Treatment

Sodium/hydrogen exchange (NHE) inhibitors show promise as potential therapeutic agents for the treatment of heart failure, but it is not known whether they can reverse the maladaptive remodeling that results in heart failure. We sought to determine the effect of the NHE-1-specific inhibitor EMD-87580 (EMD) on heart failure produced by myocardial infarction in the rat and to assess whether up to 4 wk of treatment delay results in beneficial effects. Male Sprague-Dawley rats were subjected to coronary artery ligation (or a sham procedure) and followed for up to 3 mo, at which time hypertrophy and hemodynamics were determined. EMD was provided in the diet, and treatment commenced immediately or 2–4 wk after ligation. EMD significantly reduced hemodynamic abnormalities, including the elevation in left ventricular end-diastolic pressure, and diminished the loss of systolic function with all treatment protocols. Left ventricular dilatation and hypertrophy, as assessed by heart weight, cell size, and atrial natriuretic peptide (ANP) expression, were similarly reversed to sham or near-sham levels. In addition, the increased plasma ANP and pro-ANP values were reversed to levels not significantly different from sham. Surprisingly, virtually all beneficial effects were identical with all treatment protocols. These effects were observed in the absence of infarct size reduction or blood pressure-lowering effects. Our results suggest that NHE-1 inhibition attenuates and reverses postinfarction remodeling and heart failure with a treatment delay of up to 4 wk after infarction. The effect is independent of infarct size or afterload reduction, indicating a direct effect on the myocardium.

scholarly journals Hexarelin Treatment in Male Ghrelin Knockout Mice after Myocardial Infarction

Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3847-3854 ◽  
Author(s):  
Yuanjie Mao ◽  
Takeshi Tokudome ◽  
Ichiro Kishimoto ◽  
Kentaro Otani ◽  
Hiroshi Hosoda ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Ejection Fraction ◽  
Knockout Mice ◽  
Vehicle Group ◽  
Heart Rate Variability Analysis ◽  
Coronary Artery Ligation ◽  
Synthetic Analog ◽  
Peak Rate

Both ghrelin and the synthetic analog hexarelin are reported to possess cardioprotective actions that are mainly exerted through different receptors. However, their effects on acute myocardial infarction have not been compared in vivo. This study aimed to clarify whether hexarelin treatment can compensate for ghrelin deficiency in ghrelin-knockout mice and to compare the effects of hexarelin (400 nmol/kg/d, sc) and equimolar ghrelin treatment after myocardial infarction. Myocardial infarction was produced by left coronary artery ligation in male ghrelin-knockout mice, which then received ghrelin, hexarelin, or vehicle treatment for 2 weeks. The mortality within 2 weeks was significantly lower in the hexarelin group (6.7%) and ghrelin group (14.3%) than in the vehicle group (50%) (P &lt; .05). A comparison of cardiac function 2 weeks after infarction showed that in the ghrelin and hexarelin treatment groups, cardiac output was greater, whereas systolic function, represented by ejection fraction, and diastolic function, represented by dP/dt min (peak rate of pressure decline), were significantly superior compared with the vehicle group (P &lt; .05). Hexarelin treatment was more effective than ghrelin treatment, as indicated by the ejection fraction, dP/dt max (peak rate of pressure rise), and dP/dt min. Telemetry recording and heart rate variability analysis demonstrated that sympathetic nervous activity was clearly suppressed in the hexarelin and ghrelin groups relative to the vehicle group. Our data demonstrated that hexarelin treatment can result in better heart function than ghrelin treatment 2 weeks after myocardial infarction in ghrelin-knockout mice, although both hormones have similar effects on heart rate variability and mortality.

scholarly journals Function and Mechanism of Trimetazidine in Myocardial Infarction-Induced Myocardial Energy Metabolism Disorder Through the SIRT1–AMPK Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiu-ying Luo ◽  
Ze Zhong ◽  
Ai-guo Chong ◽  
Wei-wei Zhang ◽  
Xin-dong Wu
Keyword(s):  
Myocardial Infarction ◽  
Energy Metabolism ◽  
Ischemia Reperfusion ◽  
Heart Weight ◽  
Coronary Artery Ligation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Myocardial Energy Metabolism ◽  
Atp Production ◽  
Ampk Pathway

Myocardial energy metabolism (MEM) is an important factor of myocardial injury. Trimetazidine (TMZ) provides protection against myocardial ischemia/reperfusion injury. The current study set out to evaluate the effect and mechanism of TMZ on MEM disorder induced by myocardial infarction (MI). Firstly, a MI mouse model was established by coronary artery ligation, which was then treated with different concentrations of TMZ (5, 10, and 20 mg kg–1 day–1). The results suggested that TMZ reduced the heart/weight ratio in a concentration-dependent manner. TMZ also reduced the levels of Bax and cleaved caspase-3 and promoted Bcl-2 expression. In addition, TMZ augmented adenosine triphosphate (ATP) production and superoxide dismutase (SOD) activity induced by MI and decreased the levels of lipid peroxide (LPO), free fatty acids (FFA), and nitric oxide (NO) in a concentration-dependent manner (all P &lt; 0.05). Furthermore, an H2O2-induced cell injury model was established and treated with different concentrations of TMZ (1, 5, and 10 μM). The results showed that SIRT1 overexpression promoted ATP production and reactive oxygen species (ROS) activity and reduced the levels of LPO, FFA, and NO in H9C2 cardiomyocytes treated with H2O2 and TMZ. Silencing SIRT1 suppressed ATP production and ROS activity and increased the levels of LPO, FFA, and NO (all P &lt; 0.05). TMZ activated the SIRT1–AMPK pathway by increasing SIRT1 expression and AMPK phosphorylation. In conclusion, TMZ inhibited MI-induced myocardial apoptosis and MEM disorder by activating the SIRT1–AMPK pathway.

Effects of chronic alcohol consumption on regulation of myocardial protein synthesis

2001 ◽  
Vol 281 (3) ◽  
pp. H1242-H1251 ◽  
Author(s):  
Thomas C. Vary ◽  
Christopher J. Lynch ◽  
Charles H. Lang
Keyword(s):  
Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
Alcohol Exposure ◽  
Inhibitory Effect ◽  
Initiation Factor ◽  
Heart Weight ◽  
Ethanol Administration ◽  
Translational Efficiency ◽  
Chronic Alcohol ◽  
Protein Mass

Heart disease represents an important etiology of mortality in chronic alcoholics. The purpose of the present study was to examine potential mechanisms for the inhibitory effect of chronic alcohol exposure (16 wk) on the regulation of myocardial protein metabolism. Chronic alcohol feeding resulted in a lower heart weight and 25% loss of cardiac protein per heart compared with pair-fed controls. The loss of protein mass resulted in part from a diminished (30%) rate of protein synthesis. Ethanol exerted its inhibition of protein synthesis through diminished translational efficiency rather than lower RNA content. Chronic ethanol administration decreased the abundance of eukaryotic initiation factor (eIF)4G associated with eIF4E in the myocardium by 36% and increased the abundance of the translation response protein (4E-BP1) associated with eIF4E. In addition, chronic alcohol feeding significantly reduced the extent of p70S6 kinase (p70S6K) phosphorylation. The decreases in the phosphorylation of 4E-BP1 and p70S6K did not result from a reduced abundance of mammalian target of rapamycin (mTOR). These data suggest that a chronic alcohol-induced impairment in myocardial protein synthesis results in part from inhibition in peptide chain initiation secondary to marked changes in eIF4E availability and p70S6Kphosphorylation.

Targeted inhibition of activin receptor-like kinase 5 signaling attenuates cardiac dysfunction following myocardial infarction

2010 ◽  
Vol 298 (5) ◽  
pp. H1415-H1425 ◽  
Author(s):  
Sih Min Tan ◽  
Yuan Zhang ◽  
Kim A. Connelly ◽  
Richard E. Gilbert ◽  
Darren J. Kelly
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Dysfunction ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Systolic Dysfunction ◽  
Left Ventricular ◽  
Coronary Artery Ligation ◽  
Type I ◽  
Artery Ligation ◽  
Receptor Like Kinase

Following myocardial infarction (MI), the heart undergoes a pathological process known as remodeling, which in many instances results in cardiac dysfunction and ultimately heart failure and death. Transforming growth factor-β (TGF-β) is a key mediator in the pathogenesis of cardiac remodeling following MI. We thus aimed to inhibit TGF-β signaling using a novel orally active TGF-β type I receptor [activin receptor-like kinase 5 (ALK5)] inhibitor (GW788388) to attenuate left ventricular remodeling and cardiac dysfunction in a rat model of MI. Sprague-Dawley rats underwent left anterior descending coronary artery ligation to induce experimental MI and then were randomized to receive GW788388 at a dosage of 50 mg·kg−1·day−1 or vehicle 1 wk after surgery. After 4 wk of treatment, echocardiography was performed before the rats were euthanized. Animals that received left anterior descending coronary artery ligation demonstrated systolic dysfunction, Smad2 activation, myofibroblasts accumulation, collagen deposition, and myocyte hypertrophy (all P < 0.05). Treatment with GW788388 significantly attenuated systolic dysfunction in the MI animals, together with the attenuation of the activated (phosphorylated) Smad2 ( P < 0.01), α-smooth muscle actin ( P < 0.001), and collagen I ( P < 0.05) in the noninfarct zone of MI rats. Cardiomyocyte hypertrophy in MI hearts was also attenuated by ALK5 inhibition ( P < 0.05). In brief, treatment with a novel TGF-β type I receptor inhibitor, GW788388, significantly reduced TGF-β activity, leading to the attenuation of systolic dysfunction and left ventricular remodeling in an experimental rat model of MI.

Abstract 13050: Acute Alcohol-Induced Enhanced Cardiac Depression in a Canine Model of Chronic Alcohol Consumption: Adverse Effects on Left Ventricle and Myocyte Contraction, [Ca 2+ ] i Transient and Ca 2+ Current

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Zhi Zhang ◽  
Che Cheng ◽  
Satoshi Masutani ◽  
Tiankai Li ◽  
Xiaowei Zhang ◽  
...  
Keyword(s):  
Alcohol Intake ◽  
Alcohol Exposure ◽  
Cardiac Response ◽  
Conscious Dogs ◽  
Ethanol Ingestion ◽  
Chronic Alcohol ◽  
Functional Responses ◽  
Cell Contractility ◽  
Cardiac Depression ◽  
Ras Activation

Background: Acute alcohol ingestion produces transient RAS activation. Alcoholics have an enhanced RAS activation after acute ethanol ingestion. Thus, chronic alcohol users may have enhanced cardiac functional responses to acute alcohol intake. However, it is unclear whether and how chronic alcohol intake alters cardiac response to acute alcohol exposure. We tested the hypothesis that acute alcohol may exacerbate cardiac depression and [Ca 2- ] i dysregulation, thus play important role in development of irreversible cardiomyopathy in alcoholics. Methods: We compared LV and cardiomyocyte response to acute alcohol in 6 chronically-instrumented conscious dogs before and 6 months after the once daily ingestion of alcohol (400 ml, 22% providing 33% of total daily caloric intake). Results: In conscious dogs, 6 months of alcohol significantly decreased LV contractility by 48% measured by the slopes of pressure-volume relations (E ES , 48%, 4.4 vs 8.4 mmHg/ml and M SW , 50.8 vs 98.6 mmHg) and increased the time constant of relaxation (τ, 78%, 47.8 vs 26.9 ms). In the alcoholic animals, when compared with the same animals prior to alcohol, acute alcohol (0.2 g/kg, iv, plasma level 62.3 ± 8 mg/dL) caused a greater decrease in LV contractility (47% vs 23%) and increase in τ (27% vs11%). In isolated myocytes, abrupt exposure to alcohol (250 mM) produced significant decreases in cell contraction, [Ca 2+ ] i transient ([Ca 2+ ] i ) and Ca 2+ current (I Ca,L ) in both normal and alcoholic myocytes. However, compared with the isolated cells obtained from LV biopsied tissues of the same animals prior to alcohol, the acute alcohol-induced decrease in I Ca,L (alcoholic: 50%, 1.3 vs 2.6; normal: 29%, 4.0 vs 5.6 pA/pF) was much greater in the alcoholic myocytes, the resulting reductions in the cell contractility, dL/dtmax (alcoholic: 46%, 36vs67; normal: 24%, 82vs108 μm/s), the percent shortening (49% vs 24%) and relengthening, dR/dtmax were doubled. Conclusion: In chronically alcohol-fed dogs, acute alcohol produces increased direct inhibition in LV and myocyte contractility, relaxation and exacerbates [Ca 2+ ] i hemostasis. The chronic alcohol-induced increased cardiac sensitivity to acute alcohol may play an important role in the functional impairment in alcoholic cardiomyopathy.

Abstract 3659: High-Mobility Group Box 1 Restores Cardiac Dysfunction after Myocardial Infarction in Transgenic Mice

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Tatsuro Kitahara ◽  
Yasuchika Takeishi ◽  
Tetsuro Shishido ◽  
Satoshi Suzuki ◽  
Shigehiko Kato ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Coronary Artery ◽  
Cardiac Dysfunction ◽  
Nuclear Dna ◽  
Inflammatory Responses ◽  
High Mobility ◽  
Left Ventricular ◽  
High Mobility Group ◽  
Coronary Artery Ligation ◽  
Artery Ligation

High-mobility group box 1 (HMGB1) is a nuclear DNA-binding protein and is released from necrotic cells, inducing inflammatory responses and promoting tissue repair and angiogenesis. To test the hypothesis that HMGB1 enhances angiogenesis and restores cardiac dysfunction after myocardial infarction, we generated transgenic mouse with cardiac specific overexpression of HMGB1 (HMGB1-Tg) using α-myosin heavy chain (MHC) promoter. The left anterior descending coronary artery was ligated in HMGB1-Tg and wild-type littermate (Wt) mice. After coronary artery ligation, HMGB1 was released into circulation from the necrotic cardiomyocytes of HMGB1 overexpressing hearts. The size of myocardial infarction was smaller in HMGB1-Tg than in Wt mice (figure ). Echocardiography and cardiac catheterization demonstrated that cardiac remodeling and dysfunction after myocardial infarction were prevented in HMGB1-Tg mice compared to Wt mice. Furthermore, survival rate after myocardial infarction in HMGB1-Tg mice was higher than that in Wt mice (figure ). Immunohistochemical staining revealed that capillary and arteriole formations after myocardial infarction were enhanced in HMGB1-Tg mice. We demonstrated the first in vivo evidence that HMGB1 enhances angiogenesis, restores cardiac dysfunction, and improves survival after myocardial infarction. These results may provide a novel therapeutic approach for left ventricular dysfunction after myocardial infarction.

scholarly journals Protective and Therapeutic Effects of Chinese Medicine Formula Jiajian Yunvjian on Experimental Cardiac Remodeling after Myocardial Infarction Induced by Coronary Artery Ligation

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Jun Du ◽  
Wei-liang Gu ◽  
Chang-xun Chen ◽  
Ying Wang ◽  
Jian Lv
Keyword(s):  
Myocardial Infarction ◽  
Coronary Artery ◽  
Chinese Medicine ◽  
Cardiac Remodeling ◽  
Heart Weight ◽  
Coronary Artery Ligation ◽  
Ang Ii ◽  
Artery Ligation ◽  
Weight Index ◽  
Chinese Medicine Formula

Introduction. This study was designed to explore the effect and mechanism of a classic Chinese medicine formula Jiajian Yunvjian (JJYNJ) on cardiac remodeling. Cardiac remodeling after myocardial infarction (MI) model was achieved by coronary artery ligation (CAL).Methodology. When dosed orally once daily, the effects of JJYNJ on hemodynamics, left ventricular weight index (LVWI), heart weight index (HWI), concentration, and gene expression of neuroendocrine factors as well as the histomorphological observation were determined.Results. After 4 weeks, mild cardiac remodeling in CAL group was characterized compared with sham group, but after 4 weeks of treatment of JJYNJ, hemodynamics improved, HWI reduced, and circulating angiotensin II (Ang II), endothelin-1 (ET-1), tumor necrosis factor-α(TNF-α), and hydroxyproline (Hyp) concentrations as well as Ang II receptor type 1 (AT1R) mRNA, transforming growth factorβ1(TGF-β1) mRNA, and TNF-αmRNA levels in myocardium were lower than in CAL group. Decreased plasma aldosterone (ALD) concentration, cross-sectional area of cardiomyocyte, collagen volume fraction (CVF), collagen types I and III, perivascular collagen area (PVCA), and upregulated nitric oxide (NO) levels were observed at the same time.Conclusions. These findings suggest that JJYNJ may have a protective and therapeutic function on cardiac remodeling related to MI.

Altered K+ current of ventricular myocytes in rats with chronic myocardial infarction

1998 ◽  
Vol 274 (1) ◽  
pp. H259-H265 ◽  
Author(s):  
George J. Rozanski ◽  
Zhi Xu ◽  
Kun Zhang ◽  
Kaushik P. Patel
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Hypertrophy ◽  
Pyruvate Dehydrogenase ◽  
Ventricular Myocytes ◽  
Left Ventricular ◽  
Heart Weight ◽  
Transient Outward Current ◽  
Coronary Artery Ligation ◽  
Channel Function ◽  
Failing Heart

The aim of the present study was to define the cellular mechanisms underlying changes in K+ channel function in the failing heart after myocardial infarction. Rats with left coronary artery ligation were prepared and allowed to recover for 16 wk before study. Animals with chronic infarction exhibited marked cardiac hypertrophy and signs of heart failure, as indicated by a nearly twofold increase in heart weight- and lung weight-to-body weight ratios, respectively, compared with time-matched controls. Cardiac hypertrophy was also evident by a 49% increase in whole cell capacitance of isolated left ventricular myocytes ( P < 0.05). Voltage-clamp experiments revealed that the maximum density of the Ca2+-independent, transient outward current ( I to), measured at +60 mV, was 42% less in myocytes from infarcted hearts than in myocytes from control hearts ( P < 0.05), whereas the inward rectifier current ( I K1) density was not different between groups. The reduced I to density in the infarcted group was reversed, however, in 4–5 h by treatment with exogenous dichloroacetate or pyruvate, both activators of pyruvate dehydrogenase. Moreover, control myocytes incubated for 6 h in the presence of an inhibitor of pyruvate dehydrogenase, 3-bromopyruvate, exhibited a concentration-dependent decrease in I to density compared with untreated cells. The present data demonstrate that I to density is reversibly decreased in surviving myocytes from infarcted hearts and suggest that mechanisms related to glucose metabolism via pyruvate dehydrogenase may be involved. These postinfarction changes in myocyte I to channel function may relate to impaired contractility and arrhythmogenesis, which are characteristic of the intact, failing heart.

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