Abstract 127: Mode of Injury Affects the Course of Regeneration and Repair in Neonatal and Adult Mouse Heart

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Tal Konfino ◽  
Natalie Landa-Rouben ◽  
Jonathan Leor
Keyword(s):  
Granulation Tissue ◽  
Adult Mouse ◽  
Cardiac Injury ◽  
Cardiac Regeneration ◽  
Lv Function ◽  
Mouse Heart ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Newborn Mice ◽  
Adult Mice

PURPOSE: Recent reports have demonstrated complete cardiac regeneration in newborn mice following resection of the cardiac apex. However, different types of injury could affect the mechanism of regeneration and repair. HYPOTHESIS: We aimed to test the hypothesis that the course of repair and regeneration after MI is different from apical resection in both neonatal and adult mouse heart. Methods and Results: Apical resection or permanent LAD coronary artery ligation was induced in 1-day-old or 12-week-old ICR mice. Echocardiography was used to confirm and monitor cardiac injury and remodeling. Mice were euthanized at different time points after operation, and hearts were harvested, processed, immunostained and compared with sham operated neonatal and adult hearts. Histological and immunohistochemical examination of both resected and infarcted neonatal hearts revealed inflammation and granulation tissue formation within 3 to 5 days. In the resected hearts, early regeneration was identified at the injured sites, and marked dedifferentiation of cardiomyocytes, represented by sarcomeric disassembly and marginalization, was evident around the injured areas. In addition, we noticed intensive proliferation of young cardiomyocytes which infiltrated the granulation tissue and formed a new myocardium within 21 days. In contrast, incomplete regeneration with residual small infract was detected 28 days after coronary occlusion. Echocardiography at 2,7,14 and 28 days after MI confirmed deteriorating LV function and LV remodeling with apical aneurysm formation. Surprisingly, 21 days after cardiac injury in adult mice, MI produced typical, thin, fibrotic scar whereas apical resection produced an apical tumor-like thick scar. Conclusions: The mode of injury, whether resection or infarction, affect regeneration and repair in both neonatal and adult mouse heart. Particularly, after apical resection, the newborn heart almost completely regenerates whereas regeneration is incomplete after MI, suggesting that infarction and subsequent inflammation might inhibit complete regeneration. Understanding these differences could be translated to development of new approaches to induce myocardial regeneration in adult heart.

Abstract 15: Limiting GRK2 in the Ischemic Heart can Promote Cardiac Regeneration

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Maria Cecilia Scimia ◽  
Lin Zuo ◽  
Kate E Sydnes ◽  
Daniel A Zuppo ◽  
Erhe Gao ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Cardiac Injury ◽  
Cardiac Regeneration ◽  
Cardiac Repair ◽  
Functional Improvement ◽  
Coronary Artery Ligation ◽  
Therapeutic Effects ◽  
Artery Ligation ◽  
C Terminus ◽  
Independent Effects

The detrimental role of G protein-coupled receptor (GPCR) kinase (GRK2) following cardiac injury/stress has been documented over the last two decades. Importantly, our lab has shown that inhibition or deletion of GRK2 in cardiomyocytes can prevent and also rescue heart failure (HF) phenotypes. Its role in GPCR desensitization including regulation of β-adrenergic receptors (βARs) during HF development has been well characterized. However, recently our lab and others have found that GRK2 can have novel GPCR-independent effects in the heart that appear to contribute to its pathological effects and thus, inhibition of these actions of GRK2 may contribute to therapeutic effects seen. In this study we explored whether the cardiac repair observed with lower myocardial GRK2 might involve regenerative processes. In cardiac-specific GRK2 knockout (KO) mice and also transgenic mice with cardiac-targeted expression of the βARKct, a peptide inhibitor of GRK2 activation via Gβγ sequestration, we induced HF via coronary artery ligation and subsequent myocardial infarction (MI) and measured aspects of cardiac repair including potential regeneration indices. Post-MI mice (GRK2 KO, βARKct mice and wild-type and non-transgenic control mice) were treated with 5-ethynyl-2’-deoxyuridine (EdU) or Bromodeoxyuridine (BrDU) to examine indices of DNA proliferation in myocytes as well as Ki67 staining. We also quantitated c-kit+ cells and myocytes in the post-MI hearts to compare how either loss of GRK2 expression or inhibition via its C-terminus altered potential regeneration mechanisms compared to control mice with endogenous GRK2 levels and activity. We found significantly more BrDU positive myocytes in post-MI hearts with lower GRK2 and this correlated with increased myocytes that were also cKit+. Thus, it appears that the myocardial functional improvement seen in the post-MI heart with targeted lowering of GRK2 involves, to at least a certain extent, regenerative mechanisms. This adds novel insight into the therapeutic potential of GRK2 inhibition for HF.

Abstract 16163: Hydrogen Sulfide Reduces Inflammasome Formation in Mice With Ischemic HFrEF

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Adolfo G Mauro ◽  
Juan Valle Raleigh ◽  
Khoa Nguyen ◽  
David E Durrant ◽  
Erica Kim ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Saline Control ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Reduced Ejection Fraction ◽  
Fractional Shortening

Background: Hydrogen sulfide (H2S) has been shown to attenuate myocardial ischemia/reperfusion injury via suppression of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. Whether the H2S donor, Na2S, protects against ischemic heart failure with reduced ejection fraction (HFrEF) when treatment is initiated after development of LV dysfunction is unknown. Methods and Results: Adult male mice underwent myocardial infarction (MI) by permanent coronary artery ligation after baseline echocardiography. Repeat echocardiography was performed at day 3 post MI and surviving mice with fractional shortening (FS) less than 25% were treated with either Na2S (100 μg/kg, ip) or saline (volume matched, ip) for 25 days. LV fractional shortening remained unchanged at 7 and 28 days post-MI in the saline group, but improved significantly with Na2S at both time points (Fig. A). Moreover, LV infarct scar size, assessed by trichrome staining, was smaller in Na2S group (14.8 ± 2.1%) as compared to control (28.8 ± 4.8%, P<0.05) at 7 days post MI. Immunofluorescence staining for apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), a component of the inflammasome, showed significant increase at 3 days post MI with sustained elevation at 7 days in the saline-treated group, whereas treatment with Na2S starting on day 3 post-MI significantly attenuated ASC 4 days later (Fig. B). Survival rate was 2-fold higher in Na2S group compared to saline control at 28 days post MI (P<0.05, Fig. C). Conclusion: Treatment with Na2S in mice with ischemic HFrEF improves LV function and survival up to 28 days post MI, possibly through suppression of ASC and prevention of further NLRP3 inflammasome formation. We propose that H2S donors can be promising therapeutic tools for ischemic HF.

Abstract 132: Cardiomyocyte Specific Conditional Overexpression Of Stromal Cell Derived Factor 1 Facilitates Cardiac Regeneration After Permanent Coronary Artery Ligation In Mice.

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Detlef Obal ◽  
Kenneth Brittian ◽  
Michael Book ◽  
Aruni Bhatnagar ◽  
Yiru Guo ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Stromal Cell ◽  
Cardiac Regeneration ◽  
Left Ventricular ◽  
Border Zone ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Casein Kinase 1 ◽  
Coronary Ligation ◽  
Stromal Cell Derived Factor

Background: Interruption of cardiac stromal cell derived factor 1 (SDF1)-CXCR4 axis by chronic AMD3100 administration increased myocardial injury after permanent coronary artery ligation demonstrating the important role of this chemokine in cardiac regeneration. Hypothesis: Cardiomyocyte specific conditional overexpression of SDF1 prevents heart failure after permanent coronary ligation and facilitates cardiac regeneration. Methods and Results: Tetracycline-controlled, αMyHC promoter directed overexpression of cardiac SDF1, resulted in a significant increase of SDF1 expression (SDF1: 8.1 ng/mg protein) compared to littermate WT mice (0.02 ng/mg protein) four weeks after doxycycline withdraw. SDF1 overexpression increased AKT and casein kinase 1 levels in the heart. Although there was no difference in cardiac function and scar size 1 week after infarction, SDF1 overexpression improved left ventricular (LV) ejection fraction (SDF1 [n=13]: 47±5% [mean±SEM] vs. WT [n=15]: 29±4%, p<0.05) decreased end-diastolic volume (78±10 vs. 158±30, p<0.05) and reduced infarct size measured by trichrome staining (13±3% vs. 23±3% of LV wall, p<0.05) 4 weeks after permanent ligation. Bromodeoxyuridine (BrdU) staining revealed increased regeneration indicated by a 5-fold increase in BrdU + cardiomyocyte (CM) nuclei in the borderzone of the infarct (22±3% vs. 5±1% CM nuclei, p<0.01). Increased proliferation in SDF1 mice was confirmed by a higher number of KI67 + cells compared to WT mice. Cardiomyocyte cross sectional area in the border zone was significantly reduced in SDF1 mice (365±13 μm 2 vs. 434±10 μm 2 , p<0.001) while capillary density was unchanged (2348±151/ mm 2 vs. 2498±153/ mm 2 ) compared to WT mice. Conclusion: This study demonstrates for the first time that cardiac specific overexpression of SDF1 increases myocardial regeneration and improves LV function 4 weeks after permanent coronary ligation.

Abstract MP164: Electrophysiologic Conservation of Epicardial Conduction Dynamics After Myocardial Infarction in Newborn Piglets

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Hanjay Wang ◽  
Terrence Pong ◽  
Haley Lucian ◽  
Joy Aparicio-Valenzuela ◽  
Yuko Tada ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
High Resolution ◽  
Electrical Conduction ◽  
Conduction Block ◽  
Cardiac Regeneration ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Newborn Piglets ◽  
High Resolution Mapping ◽  
Resolution Mapping

Introduction: Newborn piglets reportedly exhibit natural heart regeneration after myocardial infarction (MI). However, the electrophysiologic properties of this regenerated muscle have not been examined. We hypothesized that epicardial electrical conduction is preserved after MI in newborn piglets. Methods: Yorkshire-Landrace piglets underwent left anterior descending coronary artery ligation on postnatal day 1 (P1, n=4) or postnatal day 7 (P7, n=7), infarcting the anteroseptal left ventricle through which the Purkinje conduction system passes. After 7 weeks, cardiac magnetic resonance imaging (MRI) was performed with late gadolinium enhancement for fibrosis analysis. Epicardial conduction mapping was performed using custom 3D-printed, 256-channel high-resolution mapping arrays (Fig 1A). Age- and weight-matched healthy pigs served as controls (n=7). Data are expressed as mean±SD. Results: MRI analysis revealed significant differences between the control, P1, and P7 groups in ejection fraction (47.6±3.1% vs 37.6±3.3% vs 30.2±6.6%, p<0.001, Fig 1B) and the degree of transmural anteroseptal LV scar (0.0±0.0% vs 9.1±5.4% vs 15.4±4.2%, p<0.001), respectively. Evidence of infarcted myocardium was identified with high-resolution mapping in the P1 and P7 piglets (black arrows, Fig 1C-F). Epicardial electrical conduction was preserved in control and all P1 pigs (Figs 1C-D), whereas variable conduction block or aberrant propagation were observed in all P7 pigs (Fig 1E-F, p=0.001). Conclusion: P1 piglets exhibited incomplete natural cardiac regeneration after MI but nevertheless demonstrated electrophysiologic conservation of epicardial conduction dynamics.

Effect of chronic elevated carbon dioxide on the expression of acid-base transporters in the neonatal and adult mouse

2007 ◽  
Vol 293 (3) ◽  
pp. R1294-R1302 ◽  
Author(s):  
Amjad Kanaan ◽  
Robert M. Douglas ◽  
Seth L. Alper ◽  
Walter F. Boron ◽  
Gabriel G. Haddad
Keyword(s):  
Mammalian Cells ◽  
Adult Mouse ◽  
Brain Regions ◽  
Adult Brain ◽  
Mouse Heart ◽  
Ph Homeostasis ◽  
Acid Base ◽  
Adult Mice ◽  
Sodium Hydrogen Exchanger ◽  
The Face

Several pulmonary and neurological conditions, both in the newborn and adult, result in hypercapnia. This leads to disturbances in normal pH homeostasis. Most mammalian cells maintain tight control of intracellular pH (pHi) using a group of transmembrane proteins that specialize in acid-base transport. These acid-base transporters are important in adjusting pHi during acidosis arising from hypoventilation. We hypothesized that exposure to chronic hypercapnia induces changes in the expression of acid-base transporters. Neonatal and adult CD-1 mice were exposed to either 8% or 12% CO2 for 2 wk. We used Western blot analysis of membrane protein fractions from heart, kidney, and various brain regions to study the response of specific acid-base transporters to CO2. Chronic CO2 increased the expression of the sodium hydrogen exchanger 1 (NHE1) and electroneutral sodium bicarbonate cotransporter (NBCn1) in the cerebral cortex, heart, and kidney of neonatal but not adult mice. CO2 increased the expression of electrogenic NBC (NBCe1) in the neonatal but not the adult mouse heart and kidney. Hypercapnia decreased the expression of anion exchanger 3 (AE3) in both the neonatal and adult brain but increased AE3 expression in the neonatal heart. We conclude that: 1) chronic hypercapnia increases the expression of the acid extruders NHE1, NBCe1 and NBCn1 and decreases the expression of the acid loader AE3, possibly improving the capacity of the cell to maintain pHi in the face of acidosis; and 2) the heterogeneous response of tissues to hypercapnia depends on the level of CO2 and development.

Midterm Surgical Outcomes for ALCAPA Repair in Infants and Children

2021 ◽  
Author(s):  
Renjie Hu ◽  
Wen Zhang ◽  
Xiafeng Yu ◽  
Hongbin Zhu ◽  
Haibo Zhang ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Mitral Valve ◽  
Mitral Valve Regurgitation ◽  
Left Ventricular ◽  
Surgical Correction ◽  
Circulatory Support ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Artery Ligation

Abstract Background Surgical correction of an anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) has been associated with excellent survival during recent years. The purpose of this study was to evaluate the effectiveness of reimplantation of the coronary artery and to investigate the recovery of postoperative cardiac and mitral valve (MV) function. Methods From 2005 to 2015, 80 patients who had ALCAPA received surgical correction. Among them, 49 were infants. The median patient age was 7.8 months. Operative strategies included reimplantation of the coronary artery in 71 patients, the Takeuchi procedure in another 7 patients, and coronary artery ligation in the remaining 2 patients. Results There were 11 hospital deaths and 2 late deaths. Six patients required intraoperative or postoperative mechanical circulatory support. A significant improvement in the ejection fraction (EF) and shortening fraction (SF) was present in all surviving patients at discharge, at a 3-month follow-up and at a 1-year follow-up. MV function improved gradually after surgical repair with no late secondary intervention. Conclusions The repair of ALCAPA can be accomplished by establishment of a dual-coronary system, which offers an acceptable mortality rate and will rarely require a second surgery. Left ventricular (LV) recovery is a progressive process, especially for infants with impaired LV function. Concomitant MV annuloplasty is safe and reliable and can be performed as necessary in patients with moderate or severe mitral valve regurgitation.

Abstract P345: The Neuregulin Glial Growth Factor 2 (GGF2) Produces Sustained Improvement in Left Ventricular Function in Rats with Both Early and Established Heart Failure

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Anindita Ganguly ◽  
Erika Troy ◽  
Maya Srinivas ◽  
Andrea Vecchione ◽  
Patrick Sarmiere ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Cardiac Development ◽  
Left Ventricular ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Sustained Improvement ◽  
Delayed Initiation

Neuregulin-1β is essential for fetal cardiac development and adult cardiac function. Previous reports indicate that neuregulins improve left ventricular function in heart failure models, however the duration of the functional improvements with early or late initiation of neuregulin treatment has not been characterized. The present studies examine the effects of early and delayed initiation of intravenous GGF2 treatment on left ventricular (LV) function in rats with myocardial infarction (MI). Rats underwent surgically-induced MI by left anterior coronary artery ligation. Treatment with vehicle or GGF2 (2.6 mg/kg) was initiated at 2 or 16 w post-MI and continued once or twice weekly or once every two weeks for the in-life duration of the study (approximately 40 weeks). LV function was assessed echocardiographically up to once weekly for the duration of the study. Early and delayed initiation of GGF2 treatment caused sustained and significant improvement (p < 0.05) in both ejection fraction (EF) and fractional shortening (FS) in all regimens tested. The greatest improvements were seen with the once weekly dosing paradigm after early initiation (average EF (%) at 40 weeks post initiation of dosing: vehicle = 44.4 ± 6.0, n = 8 rats, vs. GGF2 = 64.7±6.1. n = 9 rats) and twice weekly dosing paradigm after delayed initiation (average EF (%) at 4 weeks post initiation of dosing: vehicle = 34.18±1.6, n = 7 rats, vs. GGF2 = 50.69±4.68, n = 7 rats). In addition, LV function improved when rats were re-challenged with GGF2 following an extended wash out period. This observation indicates potential efficacy for treatment paradigms that utilize intermittent dosing. These findings suggest that GGF2 produces sustained improvement in LV function after early or delayed initiation of treatment following MI in rats.

Abstract 249: Chronic Neuregulin-1β Treatment Mitigates the Progression of Post-myocardial Infarction Heart Failure in the Setting of Type 1 Diabetes Mellitus

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Manisha Gupte ◽  
Hind Lal ◽  
Firdos Ahmad ◽  
Lin Zhong ◽  
Douglas B Sawyer ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Type 1 Diabetes ◽  
Heart Function ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Artery Ligation

Aim: Neuregulin-1β (NRG-1β), a growth factor critical for cardiac development as well as maintenance of heart function after injury has been shown to significantly improve heart function in preclinical rodent models. Importantly, number of studies are ongoing to test the efficacy of NRG-1β as a treatment for patients with chronic heart failure. However, the efficacy of recombinant NRG-1β in a typ1 diabetic model of heart failure due to myocardial infarction (MI) has not been investigated. The aim of the present study was to determine the efficacy of exogenous NRG-1β to improve residual cardiac function after MI in type1 diabetic rats. Methods and Results: Sprague Dawley rats were induced type 1 diabetes by a single injection of streptozotocin (STZ) (65 mg/kg). Two weeks after induction of type 1 diabetes, rats underwent left coronary artery ligation to induce MI. STZ-diabetic rats were treated with saline or NRG-1β (100 ug/kg) twice a week for 7 weeks, starting two weeks prior to experimental MI. Residual left ventricular (LV) function was significantly greater in the NRG-1β-treated STZ-diabetic MI group compared to the vehicle-treated STZ-diabetic MI group 5 weeks after MI as assessed by high-resolution echocardiography. Furthermore, NRG-1β treatment in STZ-diabetic MI rats reduced myocardial fibrosis and apoptosis as well as decreased gene expression of key oxidant-producing enzymes. Conclusion: This study demonstrates that augmentation of NRG-1β signaling in STZ-diabetic post-MI rats via therapy with exogenous recombinant NRG-1β will alleviate subsequent HF through improvements in residual LV function via protection against adverse remodeling and apoptosis.

Abstract 548: Cellular Contributions to Neonatal Cardiac Regeneration

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Adwiteeya Misra ◽  
Pearl J Quijada ◽  
Ryan Burke ◽  
Ronald Dirkx ◽  
Eric M Small
Keyword(s):  
Rna Sequencing ◽  
Troponin T ◽  
Cardiac Injury ◽  
Cardiac Regeneration ◽  
Cardiac Repair ◽  
Mouse Heart ◽  
Sequencing Data ◽  
Injury Response ◽  
Virus Serotype

While the neonatal mouse heart possesses a remarkable ability to regenerate up to a week after birth, the adult mammalian heart is susceptible to irreversible scar formation that impedes cardiac function. Such a scar is formed by the precocious deposition of extracellular matrix (ECM) by resident cardiac fibroblasts (CFs). Unlike their adult counterparts, neonatal CFs in the regenerative widow may have a unique phenotype that contributes to cardiac regeneration and scar resolution. Indeed, the neonatal cardiac ECM secreted by CFs is reported to stimulate regeneration, yet the underlying mechanisms of CF-mediated cardiac repair in the neonate has not been examined. Here, we present a strategy to establish the role of tissue resident CFs in mouse neonatal cardiac regeneration through selective cell depletion and RNA sequencing. Through the initial analysis of published RNA sequencing data, we identified an enrichment of pro-regenerative molecules such as amphiregulin (Areg) during the neonatal regenerative window. Areg, an epidermal growth factor ligand, has been shown to paradoxically stimulate both cardiac repair and pathological fibrosis after adult cardiac injury. To assess its impact on the neonatal cardiac injury response, we developed an adeno-associated virus serotype 9 with the complete coding sequence of mouse Areg (AAV9:Areg) controlled by the cardiomyocyte-specific cardiac troponin T promoter. In vivo , AAV9:Areg treated mice accumulate BrdU+ (proliferative) non-myocytes adjacent to Areg-expressing cardiomyocytes. Ongoing studies are aimed at evaluating the contribution of CFs to neonatal cardiac repair, including whether Areg-dependent cellular changes impact CFs in the neonatal regenerative window in a manner distinct from that in the adult injury response.

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