scholarly journals Myocardial-restricted ablation of the GTPase RAD results in a pro-adaptive heart response in mice

2019 ◽  
Vol 294 (28) ◽  
pp. 10913-10927 ◽  
Author(s):  
Brooke M. Ahern ◽  
Bryana M. Levitan ◽  
Sudhakar Veeranki ◽  
Mihir Shah ◽  
Nemat Ali ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Contractile Function ◽  
Heart Function ◽  
Unmet Need ◽  
Calcium Transient ◽  
Adverse Outcomes ◽  
Endoplasmic Reticulum Calcium ◽  
Functional Remodeling ◽  
Improve Heart Function ◽  
Sustained Increase

Existing therapies to improve heart function target β-adrenergic receptor (β-AR) signaling and Ca2+ handling and often lead to adverse outcomes. This underscores an unmet need for positive inotropes that improve heart function without any adverse effects. The GTPase Ras associated with diabetes (RAD) regulates L-type Ca2+ channel (LTCC) current (ICa,L). Global RAD-knockout mice (gRAD−/−) have elevated Ca2+ handling and increased cardiac hypertrophy, but RAD is expressed also in noncardiac tissues, suggesting the possibility that pathological remodeling is due also to noncardiac effects. Here, we engineered a myocardial-restricted inducible RAD-knockout mouse (RADΔ/Δ). Using an array of methods and techniques, including single-cell electrophysiological and calcium transient recordings, echocardiography, and radiotelemetry monitoring, we found that RAD deficiency results in a sustained increase of inotropy without structural or functional remodeling of the heart. ICa,L was significantly increased, with RAD loss conferring a β-AR–modulated phenotype on basal ICa,L. Cardiomyocytes from RADΔ/Δ hearts exhibited enhanced cytosolic Ca2+ handling, increased contractile function, elevated sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, and faster lusitropy. These results argue that myocardial RAD ablation promotes a beneficial elevation in Ca2+ dynamics, which would obviate a need for increased β-AR signaling to improve cardiac function.

scholarly journals Photobiomodulation Regulation as One Promising Therapeutic Approach for Myocardial Infarction

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xinlu Gao ◽  
Wenwen Zhang ◽  
Fan Yang ◽  
Wenya Ma ◽  
Benzhi Cai
Keyword(s):  
Myocardial Infarction ◽  
Molecular Mechanisms ◽  
Contractile Function ◽  
Heart Function ◽  
Myocardial Necrosis ◽  
Atp Synthesis ◽  
Source Power ◽  
Positive Effects ◽  
Promising Therapeutic Approach ◽  
Improve Heart Function

Myocardial infarction refers to myocardial necrosis caused by acute or persistent coronary ischemia and hypoxia. It is considered to be one of the significant crises threatening human health in the world. Following myocardial infarction, collagen gradually replaces the original tissue due to the loss of many cardiomyocytes, myocardial contractile function decreases, and myocardial fibrosis eventually leads to heart failure. Phototherapy is a new treatment which has shown superior efficacy on the nerve, skeletal muscle, skin, and other tissues. Likewise, there is growing evidence that phototherapy also has many positive effects on the heart. Therefore, this article introduces the progress of research on phototherapy as a new therapeutic strategy in the treatment of myocardial infarction. The wavelength of photobiomodulation in the treatment of myocardial infarction is specific, and the influence of light source power and light duration on the tissue presents a bell-shaped distribution. Under these conditions, phototherapy can promote ATP synthesis and angiogenesis, inhibit the inflammatory response, improve heart function, reduce infarct size, and protect myocardium. In addition, we summarized the molecular mechanisms of phototherapy. According to the location of photoreceptors, they can be divided into mitochondrial and nonmitochondrial parts.

Abstract O-3: A β1-Adrenergic Receptor/β-Arrestin1-Regulatable MicroRNA, MiR-150 Protects the Mouse Heart from Ischemic Injury by Repressing Pro-apoptotic Egr2 and P2x7r

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Il-man Kim ◽  
Yaoping Tang ◽  
Yongchao Wang ◽  
Kyoung-mi Park ◽  
Qiuping Hu
Keyword(s):  
Adrenergic Receptor ◽  
Cardiac Injury ◽  
Ischemic Injury ◽  
Mouse Heart ◽  
Functional Remodeling ◽  
Β Blocker ◽  
Genetic Deletion ◽  
Circulating Levels ◽  
Cardiomyocyte Survival

MicroRNA (miR)-150 is down-regulated in patients with acute myocardial infarction (AMI), atrial fibrillation, dilated and ischemic cardiomyopathy as well as in various mouse heart failure (HF) models. Circulating miR-150 has been recently proposed as a better biomarker of HF than clinically used markers such as brain natriuretic peptide. We recently showed that β-arrestin1-biased β1-adrenergic receptor (β1AR) cardioprotective signaling activated by the β-arrestin-biased β-blocker, carvedilol (Carv) stimulates the processing of miR-150 in the heart (see figure A). However, the potential role of miR-150 in ischemic injury and HF is unknown. Here, we show that genetic deletion of miR-150 in mice causes abnormalities in cardiac structural and functional remodeling after MI. The cardioprotective roles of miR-150 during ischemic injury were attributed to repression of the pro-apoptotic genes egr2 (zinc binding transcription factor induced by ischemia) and p2x7r (pro-inflammatory ATP receptor) [see figure B]. These findings reveal a pivotal role for miR-150 as a regulator of cardiomyocyte survival during cardiac injury. In conclusion, our study will help to stratify HF patients that may respond better to β-arrestin-biased β-blockers, which is guided by circulating levels of miR-150.

Abstract 339: Long-term AAV6-βARKct Myocardial Gene Therapy Improves Cardiac Function Via Restoration Of β-Adrenergic Receptor Signaling And Neurohormonal Status Of The Failing Heart

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Giuseppe Rengo ◽  
Anastasios Lymperopoulos ◽  
Carmela Zincarelli ◽  
Maria Donniacuo ◽  
Stephen Soltys ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Gene Delivery ◽  
Cardiac Function ◽  
Adrenergic Receptor ◽  
Fluorescent Protein ◽  
Heart Function ◽  
Weight Ratio ◽  
Intramyocardial Injection ◽  
Molecular Abnormalities ◽  
Virus Serotype

BACKGROUND: The up-regulation of G protein-coupled receptor kinase-2 (GRK2) that is present in compromised myocardium contributes to dysfunctional β-adrenergic receptor (βAR) signaling and cardiac function in heart failure (HF). The peptide βARKct, which inhibits the activation of GRK2, has been shown in acute gene transfer experiments to rescue HF. This study was designed to evaluate chronic βARKct expression in post-myocardial infarction (MI) induced HF using stable myocardial gene delivery with adeno-associated virus serotype-6 (AAV6). METHODS AND RESULTS: In 12 week post-MI HF rats, we delivered βARKct or as a control, Green Fluorescent Protein, via direct intramyocardial injection. We also treated groups with concurrent administration of metoprolol. We found robust and long-lasting (up to 12 weeks post-delivery) transgene expression in the left ventricle (LV) and βARKct expression resulted in significantly improved global heart function as LV ejection fraction and ±dP/dt were increased, whereas LV end diastolic diameter and pressure were decreased. At the molecular level, cardiac βAR density and cAMP accumulation significantly improved over control groups. Fibrotic and hypertrophy markers, as well as heart-to-body weight ratio were markedly decreased by βARKct gene therapy indicating active reversal of adverse LV remodeling. For the first time, we found that chronic βARKct expression and normalization of cardiac βAR signaling led to a reduction of circulating levels of cardiotoxic neurohormones (catecholamines and aldosterone) demonstrating a potential additive mechanism of GRK2 inhibition. Concomitant metoprolol administration preserved the gain in inotropy achieved by βARKct, suggesting compatibility of these two therapeutic modalities, however, metoprolol alone only prevented the deterioration of cardiac function in HF. CONCLUSIONS : Chronic cardiac βARKct gene therapy for HF treatment via AAV6-mediated intracardiac gene delivery is feasible and results in improved cardiac function accompanied by restoration of βAR molecular abnormalities and amelioration of neurohormonal status of HF. These findings suggest βARKct gene therapy might be clinically applicable and of significant value for human HF treatment. This research has received full or partial funding support from the American Heart Association, AHA Great Rivers Affiliate (Delaware, Kentucky, Ohio, Pennsylvania & West Virginia).

A Comparative Study of Short-Term Blood Pressure Variability in Hemodialysis Patients with and without Intradialytic Hypertension

2018 ◽  
Vol 48 (4) ◽  
pp. 295-305 ◽  
Author(s):  
Athanasios Bikos ◽  
Elena Angeloudi ◽  
Evangelos Memmos ◽  
Charalampos Loutradis ◽  
Antonios Karpetas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Risk ◽  
Blood Pressure Variability ◽  
Hemodialysis Patients ◽  
Adverse Outcomes ◽  
Short Term ◽  
Ambulatory Bp Monitoring ◽  
Average Real Variability ◽  
Regular Hemodialysis ◽  
Sustained Increase

Background: Short-term blood pressure (BP) variability (BPV) is associated with increased cardiovascular risk in hemodialysis. Patients with intradialytic hypertension have high risk of adverse outcomes. Whether BPV is increased in these patients is not clear. The purpose of this study was to compare short-term BPV in patients with and without intradialytic hypertension. Methods: Forty-one patients with and 82 patients without intradialytic hypertension (intradialytic SBP rise ≥10 mm Hg to > 150 mm Hg) matched in a 1: 2 ratio for age, sex, and hemodialysis vintage were included. All subjects underwent 48-h ambulatory BP monitoring during a regular hemodialysis and the subsequent interdialytic interval. Brachial and aortic BPV were calculated with validated formulas and compared between the 2 groups during the 48-h and the 44-h periods and during the 2 daytime and nighttime periods respectively. Results: During 48-h or 44-h periods and daytime or nighttime, brachial SBP/DBP and aortic SBP/DBP were significantly higher in cases than in controls. All brachial SBP/DBP BPV indexes [SD, weighted SD (wSD), coefficient-of-variation (CV) and average-real-variability (ARV)] were not significantly different between groups during the 48- or 44-h periods (48-h: SBP-ARV 11.59 ± 3.05 vs. 11.70 ± 2.68, p = 0.844, DBP-ARV: 8.60 ± 1.90 vs. 8.90 ± 1.63, p = 0.357). Analysis stratified by day or night between days 1 and 2 revealed, in general, similar results. No significant differences in dipping pattern were observed between groups. Analysis of aortic BPV had similar findings. Conclusions: BPV is similar between those with and without intradialytic hypertension. However, those with intradialytic hypertension have a sustained increase in systolic and diastolic BP during the entire interdialytic interval.

Cellular and functional defects in a mouse model of heart failure

2000 ◽  
Vol 279 (6) ◽  
pp. H3101-H3112 ◽  
Author(s):  
Giovanni Esposito ◽  
L. F. Santana ◽  
Keith Dilly ◽  
Jader Dos Santos Cruz ◽  
Lan Mao ◽  
...  
Keyword(s):  
Heart Failure ◽  
Adrenergic Receptor ◽  
Heart Function ◽  
Imaging Techniques ◽  
Single Cells ◽  
Structural Protein ◽  
Muscle Lim Protein ◽  
Intracellular Ca ◽  
Whole Heart

Heart failure and dilated cardiomyopathy develop in mice that lack the muscle LIM protein (MLP) gene (MLP−/−). The character and extent of the heart failure that occurs in MLP−/− mice were investigated using echocardiography and in vivo pressure-volume (P-V) loop measurements. P-V loop data were obtained with a new method for mice (sonomicrometry) using two pairs of orthogonal piezoelectric crystals implanted in the endocardial wall. Sonomicrometry revealed right-shifted P-V loops in MLP−/−mice, depressed systolic contractility, and additional evidence of heart failure. Cellular changes in MLP−/− mice were examined in isolated single cells using patch-clamp and confocal Ca2+ concentration ([Ca2+]) imaging techniques. This cellular investigation revealed unchanged Ca2+ currents and Ca2+ spark characteristics but decreased intracellular [Ca2+] transients and contractile responses and a defect in excitation-contraction coupling. Normal cellular and whole heart function was restored in MLP−/− mice that express a cardiac-targeted transgene, which blocks the function of β-adrenergic receptor (β-AR) kinase-1 (βARK1). These data suggest that, despite the persistent stimulus to develop heart failure in MLP−/− mice (i.e., loss of the structural protein MLP), downregulation and desensitization of the β-ARs may play a pivotal role in the pathogenesis. Furthermore, this work suggests that the inhibition of βARK1 action may prove an effective therapy for heart failure.

scholarly journals Chronic Perinatal Hypoxia Delays Cardiac Maturation in a Mouse Model for Cyanotic Congenital Heart Disease

2020 ◽  
Author(s):  
Jennifer Romanowicz ◽  
Zaenab Dhari ◽  
Devon Guerrelli ◽  
Colm Mulvany ◽  
Marissa Reilly ◽  
...  
Keyword(s):  
Gene Expression ◽  
Congenital Heart Disease ◽  
Heart Disease ◽  
Congenital Heart ◽  
Chronic Hypoxia ◽  
Cardiac Development ◽  
Contractile Function ◽  
Adverse Outcomes ◽  
Perinatal Hypoxia ◽  
Postnatal Environment

AbstractBackgroundCompared to acyanotic congenital heart disease (CHD), cyanotic CHD has an increased risk of lifelong mortality and morbidity. These adverse outcomes may be attributed to delayed cardiomyocyte maturation, since the transition from a hypoxic fetal milieu to oxygen rich postnatal environment is disrupted. We established a rodent model to replicate hypoxic myocardial conditions spanning perinatal development, and tested the hypothesis that chronic hypoxia impairs cardiac development.MethodsMouse dams were housed in hypoxia beginning at embryonic day 16. Pups stayed in hypoxia until postnatal day (P)8 when cardiac development is nearly complete. Global gene expression was quantified at P8 and at P30, after recovering in normoxia. Phenotypic testing included electrocardiogram, echocardiogram, and ex-vivo electrophysiology study.ResultsHypoxic animals were 48% smaller than controls. Gene expression was grossly altered by hypoxia at P8 (1427 genes affected), but normalized after recovery (P30). Electrocardiograms revealed bradycardia and slowed conduction velocity in hypoxic animals at P8, which resolved after recovery (P30). Notable differences that persisted after recovery (P30) included a 65% prolongation in ventricular effective refractory period, sinus node dysfunction, and a 24% reduction in contractile function in animals exposed to hypoxia.ConclusionsWe investigated the impact of chronic hypoxia on the developing heart. Perinatal hypoxia was associated with changes in gene expression and cardiac function. Persistent changes to the electrophysiologic substrate and contractile function warrant further investigation, and may contribute to adverse outcomes observed in the cyanotic CHD population.

scholarly journals Proinflammatory Cytokines Are Soluble Mediators Linked with Ventricular Arrhythmias and Contractile Dysfunction in a Rat Model of Metabolic Syndrome

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Evaristo Fernández-Sada ◽  
Alejandro Torres-Quintanilla ◽  
Christian Silva-Platas ◽  
Noemí García ◽  
B. Cicero Willis ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Ventricular Arrhythmias ◽  
Mechanical Performance ◽  
Contractile Function ◽  
Ex Vivo ◽  
Heart Function ◽  
Control Group ◽  
Serum Triglycerides ◽  
Rat Cardiomyocytes ◽  
Proinflammatory Mediators

Metabolic syndrome (MS) increases cardiovascular risk and is associated with cardiac dysfunction and arrhythmias, although the precise mechanisms are still under study. Chronic inflammation in MS has emerged as a possible cause of adverse cardiac events. Male Wistar rats fed with 30% sucrose in drinking water and standard chow for 25–27 weeks were compared to a control group. The MS group showed increased weight, visceral fat, blood pressure, and serum triglycerides. The most important increases in serum cytokines included IL-1β(7-fold), TNF-α(84%), IL-6 (41%), and leptin (2-fold), the latter also showing increased gene expression in heart tissue (35-fold). Heart function ex vivo in MS group showed a decreased mechanical performance response to isoproterenol challenge (ISO). Importantly, MS hearts under ISO showed nearly twofold the incidence of ventricular fibrillation. Healthy rat cardiomyocytes exposed to MS group serum displayed impaired contractile function and Ca2+handling during ISO treatment, showing slightly decreased cell shortening and Ca2+transient amplitude (23%), slower cytosolic calcium removal (17%), and more frequent spontaneous Ca2+release events (7.5-fold). As spontaneous Ca2+releases provide a substrate for ventricular arrhythmias, our study highlights the possible role of serum proinflammatory mediators in the development of arrhythmic events during MS.

Abstract 201: Enhancing Pgc-1α Activity Improves Heart Function Through Activating Mitochondrial Biogenesis in Chagas Disease

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Xianxiu Wan ◽  
Jianjun Wen ◽  
Koo Sue-jie
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Biogenesis ◽  
Heart Function ◽  
Mrna Levels ◽  
Beneficial Effects ◽  
Expression Of Genes ◽  
Improve Heart Function ◽  
Mtdna Replication ◽  
Substantial Decline ◽  
Nuclear Levels

Chronic chagasic cardiomyopathy (CCM) is presented with ventricular hypertrophy and contractile dysfunction that can lead to heart failure. I have found that a substantial decline in mitochondrial biogenesis and SIRT1/PGC-1α activity ensue in chronic chagasic mice. It was evidenced by the decline in mitochondrial DNA content as well as mRNA levels of mitochondrial encoded genes and mtDNA replication machinery. Further, the activity of SIRT1 (required for PGC-1α activation) was decreased and associated with decreased nuclear levels of PGC-1-regulated NRF1 transcription factor in chagasic hearts. The mitochondrial size and number were also reduced in chagasic heart, determined by electron microscopy. Therefore, we hypothesized that enhancing the SIRT1/PGC-1α activity by SIRT1 agonist would improve heart function through activating mitochondrial biogenesis in Chagasic disease. Mice were infected with T. cruzi, and beginning at day 90 post-infection (pi), treated with resveratrol (SIRT1 agonist) or metformin (AMPK agonist, can enhance SIRT1 activity) for 21 days; and then heart function was monitored at 150 days pi. We found that treatment with resveratrol partially attenuated the heart dysfunction (stroke volume, cardiac output, ejection fraction, heart rate) and cardiac hypertrophy in chagasic mice. These benefits were associated with improved expression of the mitochondrial DNA encoded genes and mtDNA content though the expression of genes involved in mtDNA replication was not improved. Treatment with metformin was not significantly beneficial in improving the CCM outcomes. The partial beneficial effects of resveratrol could be due to inefficient activation of SIRT1 or delayed start of the treatment. We plan to treat mice with SIRT1 agonist SIRT1720 (10 fold more active than resveratrol) during the indeterminate phase of T. cruzi infection in next set of experiments. This study will improve our understanding of the molecular and immune mechanisms of chagasic heart disease and will provide a novel treatment for chronically-infected chagasic patients.

Abstract 216: Tat Delivery of a Pten Peptide Inhibitor Has Direct Cardioprotective Effects and Improves Outcomes in Rodent Models of Cardiac Arrest

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Xiangdong Zhu ◽  
Jing Li ◽  
Huashan Wang ◽  
Filip Gasior ◽  
Chunpei Lee ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Mouse Model ◽  
Pyruvate Dehydrogenase ◽  
Contractile Function ◽  
Heart Function ◽  
Isolated Heart ◽  
Lactate Production ◽  
Polyol Pathway ◽  
Protective Effects ◽  
Cardiac Arrest Survival

Introduction: We have recently shown that pharmacologic inhibition of PTEN significantly increases cardiac arrest survival in a mouse model, however, this protection required pretreatment 30 min prior to the arrest. To improve the onset of PTEN inhibition during cardiac arrest treatment, we have designed a TAT fused cell-permeable peptide (TAT-PTEN9c) for rapid tissue delivery and protection. Hypothesis: We hypothesized that TAT-PTEN9c interferes with the endogenous PTEN binding to its regulatory proteins, resulting in reduced PTEN activity, improved mouse survival and cardiac functional recovery. The improved survival is in part due to enhanced glycolysis and reduced shunting to polyol pathway and osmotic injury in heart and brain. Methods: TAT-PTEN9c (7.5 mg/kg) was given intravenously after CA in mouse to determine protective effects of the treatment on survival and heart function. Western blot was used to determine the efficacy of TAT-PTEN9c for enhancing Akt and PDH E1α activity. The effect of TAT-PTEN9c on sorbitol accumulation in tissues was measured by spectrophotometer using NAD as substrate. Direct effect of TAT-PTEN9c treatment on cardiac function were also measured in Langendorff model of isolated rat heart. Results: In the mouse model of cardiac arrest, survival was significantly increased in the TAT-PTEN9c treated group compared to saline controls at 4 h after CPR. The treated mice had increased Akt phosphorylation and pyruvate dehydrogenase dephosphorylation at R30 min in heart tissues with significantly decreased sorbitol content and reduced release of taurine and glutamate into blood, suggesting improved metabolic recovery and glucose utilization. For the isolated heart model, RPP was reduced by 25% for non-treatment groups following arrest. With TAT-PTEN9c treatment, cardiac contractile function was completely recovered. TAT-PTEN9c significantly increased lactate production at 20 min of reperfusion, indicating increased glycolysis. Conclusion: TAT-PTEN9c enhances Akt and pyruvate dehydrogenase activity and decrease glucose shunting to the polyol pathway in critical organs, preventing osmotic injury and early cardiovascular collapse and death.

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