Abstract 15378: Mitochondrial Fission Plays a Crucial Role in Cardiomyocyte Adaptation to Energy Stress via Mitophagy

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yoshiyuki Ikeda ◽  
Yasuhiro Maejima ◽  
Mitsuru Ohishi ◽  
Junichi Sadoshima
Keyword(s):  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Glucose Deprivation ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Energetic Stress ◽  
Energy Stress

Mitochondria are dynamic organelles that undergo fusion and fission. This study aims to clarify the role of mitochondrial dynamics on energetic stress resistance in cardiomyocytes (CMs). Dynamin-related protein 1 (Drp-1) which mediates mitochondrial fission was localized primarily in the cytosol in CMs. Glucose deprivation (GD) induced modest mitochondrial accumulation of Drp1 in CMs within 4 hours. Four-hour GD increased the proportion of CMs with fused mitochondria (23.5±6.9 to 35.0±10.8%, p<0.05), but also increased that of CMs with fission (2.1±0.3 to 15.5±4.8%, p<0.05) in Ad-shScr-transduced CMs, whereas mitochondria with fission did not increase after GD in Ad-shDrp1-transduced CMs (0.3±0.6 to 0.8±0.5%). These results suggest that GD induces both mitochondrial fusion and fission, and Drp1 plays an essential role in mitochondrial fission in response to GD. Transduction with Ad-shDrp1 significantly increased TUNEL-positive CMs and reduced cell viability after 4 hours of GD compared to transduction with Ad-shScr, suggesting that endogenous Drp1 protects CMs against cell death during GD. We evaluated the role of Drp1 in mediating mitophagy using mitochondria-targeted Keima fluorescence. Keima has a bimodal excitation spectrum peaking at 440 and 560 nm, corresponding to the neutral and acidic pH states, respectively. Puncta with high 560/440, indicating the presence of mitochondria in lysosomes, were significantly increased after 4 hours of GD in CMs transduced with Ad-shScr, but not in CMs transduced with Ad-shDrp, suggesting that Drp1 is necessary for stimulating autophagic mitochondrial degradation. Next, we examined the role of fission on energy stress in vivo using cardiac specific Drp1 hetero knockout (Drp1-hetCKO) mouse. Translocation of Drp1 from cytosol to mitochondria significantly increased in response to 48-hour fasting in control mice but not in Drp1-hetCKO mice. Left ventricular ejection fraction did not change after fasting in control mice (79.8±6.4 to 78.6±8.3%). However that in Drp1-hetCKO mice decreased after GD (79.4±9.7 to 48.3±11.6%, p<0.05), suggesting that Drp1 acts to preserve cardiac function during fasting. In conclusion, mitochondrial fission is crucial to adapt CMs to energy stress through mitophagy.

Risk stratification in hf with mid-range LVEF: the role of cardiopulmonary exercise testing

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
B.M.L Rocha ◽  
G.J Lopes Da Cunha ◽  
P.M.D Lopes ◽  
P.N Freitas ◽  
F Gama ◽  
...  
Keyword(s):  
Risk Stratification ◽  
Exercise Testing ◽  
Primary Endpoint ◽  
Prognostic Significance ◽  
Cardiopulmonary Exercise Testing ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Cardiopulmonary Exercise

Abstract Background Cardiopulmonary exercise testing (CPET) is recommended in the evaluation of selected patients with Heart Failure (HF). Notwithstanding, its prognostic significance has mainly been ascertained in those with left ventricular ejection fraction (LVEF) &lt;40% (i.e., HFrEF). The main goal of our study was to assess the role of CPET in risk stratification of HF with mid-range (40–49%) LVEF (i.e., HFmrEF) compared to HFrEF. Methods We conducted a single-center retrospective study of consecutive patients with HF and LVEF &lt;50% who underwent CPET from 2003–2018. The primary composite endpoint of death, heart transplant or HF hospitalization was assessed. Results Overall, 404 HF patients (mean age 57±11 years, 78.2% male, 55.4% ischemic HF) were included, of whom 321 (79.5%) had HFrEF and 83 (20.5%) HFmrEF. Compared to the former, those with HFmrEF had a significantly higher mean peak oxygen uptake (pVO2) (20.2±6.1 vs 16.1±5.0 mL/kg/min; p&lt;0.001), lower median minute ventilation/carbon dioxide production (VE/VCO2) [35.0 (IQR: 29.1–41.2) vs 39.0 (IQR: 32.0–47.0); p=0.002) and fewer patients with exercise oscillatory ventilation (EOV) (22.0 vs 46.3%; p&lt;0.001). Over a median follow-up of 28.7 (IQR: 13.0–92.3) months, 117 (28.9%) patients died, 53 (13.1%) underwent heart transplantation, and 134 (33.2%) had at least one HF hospitalization. In both HFmrEF and HFrEF, pVO2 &lt;12 mL/kg/min, VE/VCO2 &gt;35 and EOV identified patients at higher risk for events (all p&lt;0.05). In Cox regression multivariate analysis, pVO2 was predictive of the primary endpoint in both HFmrEF and HFrEF (HR per +1 mL/kg/min: 0.81; CI: 0.72–0.92; p=0.001; and HR per +1 mL/kg/min: 0.92; CI: 0.87–0.97; p=0.004), as was EOV (HR: 4.79; CI: 1.41–16.39; p=0.012; and HR: 2.15; CI: 1.51–3.07; p&lt;0.001). VE/VCO2, on the other hand, was predictive of events in HFrEF but not in HFmrEF (HR per unit: 1.03; CI: 1.02–1.05; p&lt;0.001; and HR per unit: 0.99; CI: 0.95–1.03; p=0.512, respectively). ROC curve analysis demonstrated that a pVO2 &gt;16.7 and &gt;15.8 mL/kg/min more accurately identified patients at lower risk for the primary endpoint (NPV: 91.2 and 60.5% for HFmrEF and HFrEF, respectively; both p&lt;0.001). Conclusions CPET is a useful tool in HFmrEF. Both pVO2 and EOV independently predicted the primary endpoint in HFmrEF and HFrEF, contrasting with VE/VCO2, which remained predictive only in latter group. Our findings strengthen the prognostic role of CPET in HF with either reduced or mid-range LVEF. Funding Acknowledgement Type of funding source: None

scholarly journals Non-alcoholic fatty liver disease in mice with hepatocyte-specific deletion of mitochondrial fission factor

Diabetologia ◽  
2021 ◽  
Author(s):  
Yukina Takeichi ◽  
Takashi Miyazawa ◽  
Shohei Sakamoto ◽  
Yuki Hanada ◽  
Lixiang Wang ◽  
...  
Keyword(s):  
Er Stress ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Primary Hepatocytes ◽  
Alcoholic Fatty Liver ◽  
Expression Of Genes ◽  
Specific Deletion

Abstract Aims/hypothesis Mitochondria are highly dynamic organelles continuously undergoing fission and fusion, referred to as mitochondrial dynamics, to adapt to nutritional demands. Evidence suggests that impaired mitochondrial dynamics leads to metabolic abnormalities such as non-alcoholic steatohepatitis (NASH) phenotypes. However, how mitochondrial dynamics are involved in the development of NASH is poorly understood. This study aimed to elucidate the role of mitochondrial fission factor (MFF) in the development of NASH. Methods We created mice with hepatocyte-specific deletion of MFF (MffLiKO). MffLiKO mice fed normal chow diet (NCD) or high-fat diet (HFD) were evaluated for metabolic variables and their livers were examined by histological analysis. To elucidate the mechanism of development of NASH, we examined the expression of genes related to endoplasmic reticulum (ER) stress and lipid metabolism, and the secretion of triacylglycerol (TG) using the liver and primary hepatocytes isolated from MffLiKO and control mice. Results MffLiKO mice showed aberrant mitochondrial morphologies with no obvious NASH phenotypes during NCD, while they developed full-blown NASH phenotypes in response to HFD. Expression of genes related to ER stress was markedly upregulated in the liver from MffLiKO mice. In addition, expression of genes related to hepatic TG secretion was downregulated, with reduced hepatic TG secretion in MffLiKO mice in vivo and in primary cultures of MFF-deficient hepatocytes in vitro. Furthermore, thapsigargin-induced ER stress suppressed TG secretion in primary hepatocytes isolated from control mice. Conclusions/interpretation We demonstrated that ablation of MFF in liver provoked ER stress and reduced hepatic TG secretion in vivo and in vitro. Moreover, MffLiKO mice were more susceptible to HFD-induced NASH phenotype than control mice, partly because of ER stress-induced apoptosis of hepatocytes and suppression of TG secretion from hepatocytes. This study provides evidence for the role of mitochondrial fission in the development of NASH. Graphical abstract

scholarly journals The role of neurohormonal blockers in the primary prevention of acute-, early-, and late-onset anthracycline-induced cardiotoxicity

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Ahmed Ayuna ◽  
Nik Abidin
Keyword(s):  
Primary Prevention ◽  
Myocardial Injury ◽  
Troponin I ◽  
Late Onset ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Main Body ◽  
Converting Enzyme Inhibitors ◽  
Ventricular Ejection Fraction

Abstract Background Anthracycline-induced cardiotoxicity has been classified based on its onset into acute, early, and late. It may have a significant burden on the quality and quantity of life of those exposed to this class of medication. Currently, there are several ongoing debates on the role of different measures in the primary prevention of cardiotoxicity in cancer survivors. Our article aims to focus on the role of neurohormonal blockers in the primary prevention of anthracycline-induced cardiotoxicity, whether it is acute, early, or late onset. Main body of the abstract PubMed and Google Scholar database were searched for the relevant articles; we reviewed and appraised 15 RCTs, and we found that angiotensin-converting enzyme inhibitors (ACEI) and B-blockers were the most commonly used agents. Angiotensin II receptor blockers (ARBs) and mineralocorticoid receptor antagonists (MRAs) were used in a few other trials. The follow-up period was on the range of 1–156 weeks (mode 26 weeks). Left ventricular ejection fraction (LVEF), left ventricular diameters, and diastolic function were assessed by either echocardiogram or occasionally by cardiac magnetic resonance imaging (MRI). The occurrence of myocardial injury was assessed by troponin I. It was obvious that neurohormonal blockers reduced the occurrence of LVEF and myocardial injury in 14/15 RCTs. Short conclusion Beta-blockers, especially carvedilol and ACEI, especially enalapril, should be considered for the primary prevention of acute- and early-onset cardiotoxicity. ARB and MRA are suitable alternatives when patients are intolerant to ACE-I and B-blockers. We recommend further studies to explore and establish the role of neurohormonal blockers in the primary prevention of the acute-, early-, and late-onset cardiotoxicity.

scholarly journals The role of systemic inflammation in heart failure

2021 ◽  
Vol 102 (4) ◽  
pp. 510-517
Author(s):  
E V Khazova ◽  
O V Bulashova
Keyword(s):  
Heart Failure ◽  
Cardiovascular Diseases ◽  
Systemic Inflammation ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
C Reactive Protein ◽  
Ventricular Ejection Fraction ◽  
Reactive Protein ◽  
Highly Sensitive

The discussion continues about the role of systemic inflammation in the pathogenesis of cardiovascular diseases of ischemic etiology. This article reviews the information on the role of C-reactive protein in patients with atherosclerosis and heart failure in risk stratification for adverse cardiovascular events, including assessment of factors affecting the basal level of highly sensitive C-reactive protein. Research data (MRFIT, MONICA) have demonstrated a relationship between an increased level of C-reactive protein and the development of coronary heart disease. An increase in the serum level of highly sensitive C-reactive protein is observed in arterial hypertension, dyslipidemia, type 2 diabetes mellitus and insulin resistance, which indicates the involvement of systemic inflammation in these disorders. Currently, the assessment of highly sensitive C-reactive protein is used to determine the risk of developing myocardial infarction and stroke. It has been proven that heart failure patients have a high level of highly sensitive C-reactive protein compared with patients without heart failure. The level of C-reactive protein is referred to as modifiable risk factors for cardiovascular diseases of ischemic origin, since lifestyle changes or taking drugs such as statins, non-steroidal anti-inflammatory drugs, glucocorticoids, etc. reduce the level of highly sensitive C-reactive protein. In patients with heart failure with different left ventricular ejection fraction values, it was found that the regression of the inflammatory response is accompanied by an improvement in prognosis, which confirms the hypothesis of inflammation as a response to stress, which has negative consequences for the cardiovascular system.

Electrophysiologic properties and ventricular fibrillation in normal and myopathic hearts

1999 ◽  
Vol 77 (7) ◽  
pp. 510-519 ◽  
Author(s):  
Katherine M Kavanagh ◽  
Patricia A Guerrero ◽  
Bodh I Jugdutt ◽  
Francis X Witkowski ◽  
Jeffrey E Saffitz
Keyword(s):  
Ventricular Fibrillation ◽  
Myocardial Dysfunction ◽  
Myocardial Cell ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Control Group ◽  
Functional Abnormality ◽  
Ventricular Ejection Fraction ◽  
Anisotropic Properties

This study tests the hypothesis that moderate myocardial dysfunction is associated with altered myocardial anisotropic properties and structurally altered ventricular fibrillation (VF). Mongrel dogs were randomized to either a control group or a group that was rapidly paced at 250 beats/min until the left ventricular ejection fraction was [Formula: see text] 40%. Changes in anisotropic properties and the electrical characteristics of VF associated with the development of moderate myocardial dysfunction were assessed by microminiature epicardial mapping studies. In vivo conduction, refractory periods, and repolarization times were prolonged in both longitudinal and transverse directions in myopathic animals versus controls. VF was different in myopathic versus control animals. There were significantly more conducted deflections during VF in normal hearts compared with myopathic hearts. Propagated deflection-to-deflection intervals during VF were significantly longer in myopathic hearts compared with controls (125.5 ± 49.06 versus 103.4 ± 32.9 ms, p = 0.009). There were no abnormalities in cell size, cell shape, or the number of intercellular gap junctions and there was no detectable change in the expression of the gap junction proteins Cx43 and Cx45. Moderate myocardial dysfunction is associated with significant electrophysiological abnormalities in the absence of changes in myocardial cell morphology or intercellular connections, suggesting a functional abnormality in cell-to-cell communication.Key words: cardiomyopathy, anisotropy, fibrillation, defibrillation.

Low Plasma Hydrogen Sulfide Is Associated with Impaired Renal Function and Cardiac Dysfunction

2018 ◽  
Vol 47 (5) ◽  
pp. 361-371 ◽  
Author(s):  
Qing Kuang ◽  
Ning Xue ◽  
Jing Chen ◽  
Ziyan Shen ◽  
Xiaomeng Cui ◽  
...  
Keyword(s):  
Renal Function ◽  
Hydrogen Sulfide ◽  
Cardiac Dysfunction ◽  
Mononuclear Cells ◽  
Troponin T ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Mrna Levels ◽  
Ventricular Ejection Fraction

Background: Chronic kidney disease (CKD) has been proposed to associate with decreased hydrogen sulfide (H2S) level. Nevertheless, the role of H2S in the pathogenesis of CKD has not been fully investigated. Our study aimed to investigate the plasma level of endogenous H2S in patients with different stages of CKD, and to identify the role of H2S in the progression of CKD and its relationship with cardiovascular diseases. Methods: A total of 157 non-dialysis CKD patients were recruited in our study, with 37 age- and sex-matched healthy individuals as control. Plasma concentration of H2S was measured with spectrophotometry. Sulfhemoglobin, the integration of H2S and hemoglobin, was characterized and measured by dual wavelength spectrophotometry. Serum levels of homocysteine (Hcy), cardiac troponin T (cTnT), and N-terminal pro B type natriuretic peptide were measured using automated analyzers. Conventional transthoracic echocardiography was performed and left ventricular ejection fraction (LVEF) was analyzed as a sensitive parameter of cardiac dysfunction. Results: The plasma H2S level (μmol/L) in CKD patients was significantly lower than those in healthy controls (7.32 ± 4.02 vs. 14.11 ± 5.24 μmol/L, p < 0.01). Plasma H2S level was positively associated with estimated glomerular filtration rate (eGFR; ρ = 0.577, p < 0.01) and negatively associated with plasma indoxyl sulfate concentration (ρ = –0.554, p < 0.01). The mRNA levels of cystathionine β-synthase and cystathionine γ-lyase, 2 catalytic enzymes of H2S formation, were significantly lower in blood mononuclear cells of CKD patients with respect to controls; however, the mRNA level of 3-mercaptopyruvate sulfurtransferase, as another H2S-producing enzyme, was significantly higher in CKD patients. The serum concentration of Hcy, acting as the substrate of H2S synthetase, was higher in the CKD group (p < 0.01). Specifically, the content of serum Hcy in CKD stages 3–5 patients was significantly higher than that in CKD stages 1–2, indicating an increasing trend of serum Hcy with the decline of renal function. Examination of ultrasonic cardiogram revealed a negative ­correlation between plasma H2S level and LVEF (ρ = –0.204, p < 0.05) in CKD patients. The H2S level also correlated negatively with cTnT concentration (ρ = –0.249, p < 0.01). Conclusions: Plasma H2S level decreased with the decline of eGFR, which may contribute to the cardiac dysfunction in CKD ­patients.

Abstract 165: The 18 kDa FGF-2 Prevents the Doxorubicin-induced Cardiac Damage and Amp-activated Kinase Activation, in vitro and in vivo

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Navid Koleini ◽  
Jon Jon Santiago ◽  
Barbara E Nickel ◽  
Robert Fandrich ◽  
Davinder S Jassal ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Cell Death ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Wild Type ◽  
Rat Cardiomyocytes ◽  
Ventricular Ejection Fraction ◽  
Compound C

Introduction: Protection of the heart from chemotherapeutic (Doxorubicin, DOX) drug-induced toxicity is a desirable goal, to limit side effects of cancer treatments. DOX toxicity has been linked to the activation (phosphorylation) of the AMP-activated kinase, AMPK. The 18 kDa low molecular weight isoform of fibroblast growth factor 2 (Lo-FGF-2) is a known cardioprotective and cytoprotective agent. In this study we have tested the ability of Lo-FGF-2 to protect from DOX-induced damage in rat cardiomyocytes in vitro, and in transgenic mouse models in vivo, in relation to AMPK activation. Methods: Rat neonatal cardiomyocytes in culture were exposed to DOX (0.5 μM) in the presence or absence of pre-treatment Lo-FGF-2 (10 ng/ml). Compound C was used to block phosphorylation (activity) of AMPK. Levels of cell viability/death (using Calcein-AM/Propidium iodide assay), phospho -and total AMPK, and apoptotic markers such as active caspase 3 were analyzed. In addition, transgenic mice expressing only Lo-FGF2, and wild type mice, expressing both high molecular weight (Hi-FGF2) as well as Lo-FGF2 were subjected to DOX injection (20 mg/kg, intraperitoneal); echocardiography was used to examine cardiac function at baseline and at 10 days post-DOX. Results: DOX-induced cell death of cardiomyocytes in culture was maximal at 24 hours post-DOX coinciding with significantly increased in activated (phosphorylated) AMPK. Compound C attenuated DOX-induced cardiomyocyte loss. Pre-incubation with Lo-FGF-2 decreased DOX induced cell death, and also attenuated the phosphorylation of AMPK post-DOX. Relative levels of phospho-AMPK were lower in the hearts of Lo-FGF2-expressing male mice compared to wild type. DOX-induced loss of contractile function (left ventricular ejection fraction and endocardial velocity) was negligible in Lo-FGF2-expressing mice but significant in wild type mice. Conclusion: Lo-FGF-2 protects the heart from DOX-induced damage in vitro and in vivo, by a mechanism likely involving an attenuation of AMPK activity.

Effect of hypokintic transformation on the clinical phenotype and functional capacity in hypertrophic cardiomyopathy

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Wasserstrum ◽  
E Itelman ◽  
R Barriales-Villa ◽  
X Fernandez-Fernandez ◽  
Y Adler ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Nyha Class ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Tachyarrhythmias ◽  
Ventricular Ejection Fraction ◽  
Icd Therapy ◽  
Medical Centers ◽  
Increased Risk

Abstract Background Advanced hypertrophic cardiomyopathy (HCM) may be complicated by a dilated hypokinetic transformation. Reduced left ventricular ejection fraction (HFrEF) has been described in terms of specific risks of morbidity and mortality, and specifically in terms of increased risk for fatal arrhythmias. Nevertheless, recent publications have casted doubt regarding the role of arrhythmia in non-ischemic HFrEF and questioned the role of primary prevention strategies in these cases. Methods We've reviewed clinical characteristics of 883 patients age ≥40, diagnosed with HCM who were evaluated in the cardiomyopathy clinic in two tertiary medical centers in Israel and Spain. Results Forty-five patients (5%) suffered from hypokinetic transformation. They were younger at diagnosis (median 32 [IQR 24–55] vs. 49 [35–60], p&lt;0.001), had a lower body-mass index (28.4 [±4.7] vs. 26.0 [±3.9], p&lt;0.001), and suffered more from strokes (19% vs 6%, p&lt;0.001). They had lower had a lower NYHA class (p=0.001) and lower exercise capacity (7.3 [4.5–10.8] vs. 9.6 [6.7–12.0] METS, p&lt;0.001). Patients with hypokinetic HCM had higher rates of pacemaker and implanted defibrillator (ICD) implantations (41% vs 11%, p&lt;0.001) and (43% vs 13%, p&lt;0.001) respectively. These patients had a higher incidence of sustained ventricular tachyarrhythmias (14% vs 2%, p&lt;0.001). Among patients who had an ICD, patients suffering from hypokinetic transformation had received more appropriate ICD therapy (27% vs 12%, p&lt;0.001). These patients received more heart transplantations (13% vs 1%, p&lt;0.001), and had a trend for higher incidence rate of Sudden cardiac death (6% vs 2% p=0.06) and a higher 5-year mortality rates (21% vs. 5%, p&lt;0.001). Conclusions HCM patients suffering from hypokinetic transformation have lower functional and exercise capacities, are more likely to suffer from ventricular tachyarrhythmias and experience appropriate ICD therapy, and undergo heart transplantation. They also have a significantly lower 5-year survival. Five-year survival Funding Acknowledgement Type of funding source: None

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