Cardiac Myocyte Death Research Articles

Gene Therapy Targets in Heart Failure: The Path to Translation

Heart failure (HF) is the common end point of cardiac diseases. Despite the optimization of therapeutic strategies and the consequent overall reduction in HF-related mortality, the key underlying intracellular signal transduction abnormalities have not been addressed directly. In this regard, the gaps in modern HF therapy include derangement of β-adrenergic receptor (β-AR) signaling, Ca(2+) disbalances, cardiac myocyte death, diastolic dysfunction, and monogenetic cardiomyopathies. In this review we discuss the potential of gene therapy to fill these gaps and rectify abnormalities in intracellular signaling. We also examine current vector technology and currently available vector-delivery strategies, and we delineate promising gene therapy structures. Finally, we analyze potential limitations related to the transfer of successful preclinical gene therapy approaches to HF treatment in the clinic, as well as impending strategies aimed at overcoming these limitations.

Minocycline suppresses oxidative stress and attenuates fetal cardiac myocyte apoptosis triggered by in utero cocaine exposure

This study investigates the molecular mechanisms by which minocycline, a second generation tetracycline, prevents cardiac myocyte death induced by in utero cocaine exposure. Timed mated pregnant Sprague-Dawley (SD) rats received one of the following treatments twice daily from embryonic (E) day 15-21 (E15-E21): (i) intraperitoneal (IP) injections of saline (control); (ii) IP injections of cocaine (15mg/kg BW); and (iii) IP injections of cocaine+oral administration of 25mg/kg BW of minocycline. Pups were killed on postnatal day 15 (P15). Additional pregnant dams received twice daily IP injections of cocaine (from E15-E21)+oral administration of a relatively higher (37.5mg/kg BW) dose of minocycline. Minocycline treatment continued from E15 until the pups were sacrificed on P15. In utero cocaine exposure resulted in an increase in oxidative stress and fetal cardiac myocyte apoptosis through activation of c-Jun-NH(2)-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK)-mediated mitochondria-dependent apoptotic pathway. Continued minocycline treatment from E15 through P15 significantly prevented oxidative stress, kinase activation, perturbation of BAX/BCL-2 ratio, cytochrome c release, caspase activation, and attenuated fetal cardiac myocyte apoptosis after prenatal cocaine exposure. These results demonstrate in vivo cardioprotective effects of minocycline in preventing fetal cardiac myocyte death after prenatal cocaine exposure. Given its proven clinical safety and ability to cross the placental barrier and enter into the fetal circulation, minocycline may be an effective therapy for preventing cardiac consequences of in utero cocaine exposure.

Direct monitoring of mitochondrial calcium levels in cultured cardiac myocytes using a novel fluorescent indicator protein, GCaMP2-mt

BackgroundAn opening of the mitochondrial permeability transition pore (MPTP), which leads to loss of mitochondrial membrane potential (ΔΨm), is the earliest event that commits a cell to death. Mitochondrial matrix calcium ([Ca2+]m) is considered to be a critical regulator of MPTP, but direct monitoring of [Ca2+]m is difficult with previously-reported sensors. We developed a novel fluorescent indicator for [Ca2+]m, GCaMP2-mt, by adding a mitochondrial targeting sequence to a high signal-to-noise Ca2+ sensor protein GCaMP2, and monitored dynamic changes in oxidant-induced cardiac myocyte death. Methods and resultsGCaMP2-mt was transduced into neonatal rat cardiac myocytes using a recombinant adenovirus. We confirmed that GCaMP2-mt colocalized with tetramethylrhodamine ethyl-ester, a fluorescent indicator of ΔΨm. We monitored oxidant-induced responses of [Ca2+]m and ΔΨm using time-lapse confocal microscopy. The response of [Ca2+]m was synchronous with that of cytosolic calcium and was divided into three kinetically-distinct phases; the first phase, during which [Ca2+]m maintained its baseline level; the second phase, during which [Ca2+]m showed a rapid and sudden increase; and the third phase, during which [Ca2+]m continued to increase at a slower rate until the collapse of ΔΨm. The third phase was likely to be mediated through a mitochondrial Ca2+ uniporter, because it was modulated by uniporter-acting drugs. Importantly, there was a remarkable cellular heterogeneity in the third phase, and ΔΨm loss occurred in an all-or-none manner depending on the cellular [Ca2+]m level with a clear cut-off value. ConclusionsDirect monitoring of [Ca2+]m using GCaMP2-mt provides deeper insight into the mechanism of cardiac myocyte death.

CaMKII, the Downstream Hypertrophic Signaling Pathway in the Heart: The 2009 Benedict R. Lucchesi Distinguished Lectureship Award

CaMKII, the Downstream Hypertrophic Signaling Pathway in the Heart: The 2009 Benedict R. Lucchesi Distinguished Lectureship Award

Levosimendan reduces plasma cell-free DNA levels in patients with ischemic cardiomyopathy

Heart failure (HF) is a condition associated with the apoptosis and cell death of both cardiac myocytes and cardiac non-myocytes. DNA fragments released from programmed cell death or acute cellular injury are the main sources of disease-associated elevation of cell-free (cf) DNA. We hypothesized that cfDNA could be a relevant marker of cardiac apoptosis in HF patients that could be affected by the improvement of myocardial performance. To test our hypothesis, we measured plasma cfDNA in 19 patients with ischemic HF and severe left ventricular (LV) systolic dysfunction before and 12 h after completion of levosimendan infusion. Echocardiographic and biochemical markers of LV diastolic pressure and LV systolic function were also assessed. In accordance with previous observations levosimendan improved echocardiographic and biochemical indices of LV function. Plasma cfDNA was significantly reduced in HF patients post-levosimendan treatment (median: 89.4, interquartile range: 87.1 to median: 25.9, interquartile range: 12.3, P = 0.028). Notably, in 15/19 patients there was a reduction in cfDNA levels post-levosimendan infusion; while in 12/19 patients, a more than 50% reduction in plasma cfDNA was observed. Since cfDNA is a marker of tissue injury and apoptosis these results indicate that improvement of LV function has a potential impact on cell preservation and survival. Further studies are needed to substantiate our promising results regarding the role of plasma cfDNA as a marker of HF.

Characterization of mitochondria isolated from normal and ischemic hearts in rats utilizing atomic force microscopy

Mitochondria play critical roles in both the life and the death of cardiac myocytes. Various factors, such as the loss of ATP synthesis and increase of ATP hydrolysis, impairment in ionic homeostasis, formation of reactive oxygen species (ROS), and release of proapoptotic proteins are related to the generation of irreversible damage. It has been proposed that the release of cytochrome c is caused by a swelling of the mitochondrial matrix triggered by the apoptotic stimuli. However, there is a controversy about whether or not the mitochondria, indeed, swell during apoptosis. The major advantages of atomic force microscopy (AFM) over conventional optical and electron microscopes for bio-imaging include the fact that no special coating and vacuum are required and imaging can be done in all environments—air, vacuum or aqueous conditions. In addition, AFM force–distance curve measurements have become a fundamental tool in the fields of surface chemistry, biochemistry, and material science. In this study, we used AFM to observe the morphological and property changes in heart mitochondria that were isolated from a rat myocardial infarction model. From the shape parameters of the mitochondria in the AFM topographic image, it seemed that myocardial infarction caused the mitochondrial swelling. Also, the results of force–distance measurements showed that the adhesion force of heart mitochondria was significantly decreased by myocardial in infarction. Therefore, we suggested that myocardial infarction might be the cause of mitochondrial swelling and the changes in outer membrane of heart mitochondria.

β1-Adrenergic receptor activation induces mouse cardiac myocyte death through both L-type calcium channel-dependent and -independent pathways

Cardiac diseases persistently increase the contractility demands of cardiac myocytes, which require activation of the sympathetic nervous system and subsequent increases in myocyte Ca(2+) transients. Persistent exposure to sympathetic and/or Ca(2+) stress is associated with myocyte death. This study examined the respective roles of persistent beta-adrenergic receptor (beta-AR) agonist exposure and high Ca(2+) concentration in myocyte death. Ventricular myocytes (VMs) were isolated from transgenic (TG) mice with cardiac-specific and inducible expression of the beta(2a)-subunit of the L-type Ca(2+) channel (LTCC). VMs were cultured, and the rate of myocyte death was measured in the presence of isoproterenol (ISO), other modulators of Ca(2+) handling and the beta-adrenergic system, and inhibitors of caspases and reactive oxygen species generation. The rate of myocyte death was greater in TG vs. wild-type myocytes and accelerated by ISO in both groups, although ISO did not increase LTCC current (I(Ca-L)) in TG-VMs. Nifedipine, an LTCC antagonist, only partially prevented myocyte death. These results suggest both LTCC-dependent and -independent mechanisms in ISO induced myocyte death. ISO increased the contractility of wild type and TG-VMs by enhancing sarcoplasmic reticulum function and inhibiting sarco(endo)plasmic reticulum Ca(2+)-ATPase, Na(+)/Ca(2+) exchanger, and CaMKII partially protected myocyte from death induced by both Ca(2+) and ISO. Caspase and reactive oxygen species inhibitors did not, but beta(2)-AR activation did, reduce myocyte death induced by enhanced I(Ca-L) and ISO stimulation. Our results suggest that catecholamines induce myocyte necrosis primarily through beta(1)-AR-mediated increases in I(Ca-L), but other mechanisms are also involved in rodents.

NADPH Oxidase and Cardiac Failure

Increases in oxidative stress in the heart play an important role in mediating hypertrophy, apoptosis, fibrosis, mitochondrial dysfunction, and the consequent development of heart failure. Although it has been widely believed that electron leakage from the mitochondrial electron transport chain is the primary source of oxidative stress in the failing heart, increasing lines of evidence suggest that enzymes which produce reactive oxygen species may also contribute to it. NADPH oxidases are transmembrane enzymes dedicated to producing superoxide (O(2)(-)) by transferring an electron from NAD(P)H to molecular oxygen. Nox4 is a major NADPH oxidase isoform expressed in the heart. Nox4 is localized primarily at mitochondria in cardiac myocytes, and upregulation of Nox4 hypertrophic stimuli enhances O(2)(-) production, apoptosis, and mitochondrial dysfunction, thereby playing an important role in mediating cardiac dysfunction. Since Nox4 could be a key molecule mediating oxidative stress and pathological hypertrophy, it may serve as an important target of heart failure treatment. In this review, the importance of NADPH oxidases as sources of increased oxidative stress in the failing heart and the role of Nox4 in mediating growth and death of cardiac myocytes are discussed.

The Cardiac Mitochondrion: Nexus of Stress

The emergence of mitochondria as critical regulators of cardiac myocyte survival and death has revolutionized the field of cardiac biology. Indeed, it is now well recognized that mitochondrial dysfunction plays a crucial role in the pathogenesis of multiple cardiac diseases. A panoply of mitochondrial proteins/complexes ranging from canonical apoptosis proteins such as Bcl2 and Bax, through the mitochondrial permeability transition pore, to ion channels such as mitochondrial K(ATP) channels and connexin-43 have now been implicated as critical regulators of cardiac cell death. The purpose of this review, therefore, is to focus on these mitochondrial mediators/inhibitors of cell death and to address the specific mechanisms that underlie their ability to influence cardiac pathology.

Mitochondrial Pruning by Nix and BNip3: An Essential Function for Cardiac-Expressed Death Factors

Programmed cardiac myocyte death via the intrinsic, or mitochondrial, pathway is a mechanism of pathological ventricular remodeling after myocardial infarction and during chronic pressure overload hypertrophy. Transcriptional upregulation of the closely related proapoptotic Bcl2 family members BNip3 in ischemic myocardium and Nix in hypertrophied myocardium suggested a molecular mechanism by which programmed cell death can be initiated by cardiac stress and lead to dilated cardiomyopathy. Studies using transgenic and gene knockout mice subsequently demonstrated that expression of BNip3 and Nix is both sufficient for cardiomyopathy development and necessary for cardiac remodeling after reversible coronary occlusion and transverse aortic banding, respectively. Here, these data are reviewed in the context of recent findings showing that Nix not only stimulates cardiomyocyte apoptosis but also induces mitochondrial autophagy (mitophagy) and indirectly activates the mitochondrial permeability transition pore, causing cell necrosis. New findings are presented suggesting that Nix and BNip3 have an essential function, "mitochondrial pruning," that restrains mitochondrial proliferation in cardiomyocytes and without which an age-dependent mitochondrial cardiomyopathy develops.

Role of osteopontin in heart failure associated with aging

Cardiovascular disease is one of the leading causes of death in the elderly. Much of the morbidity and mortality in the elderly is attributable to acute ischemic events leading to myocardial infarction (MI) and death of cardiac myocytes. Evidence has been provided that aging associated with adverse remodeling post MI as demonstrated by less effective myocardial repair, greater infarct expansion, and septal hypertrophy. Expression of osteopontin (OPN) increases in the heart post MI. Transgenic mice studies suggest that increased expression of OPN plays a protective role in post-MI LV remodeling by modulating collagen deposition and fibrosis. OPN, a multifunctional protein, has the potential to influence the molecular and cellular changes associated with infarct healing. The post-MI infarct healing process involves temporarily overlapping phases that include the following--(1) inflammation with migration and adhesion of neutrophils and macrophages, phagocytosis and inflammatory gene expression; (2) tissue repair with fibroblast adhesion and proliferation, myofibroblast differentiation, extracellular matrix deposition and scar formation; and (3) structural and functional remodeling of infarcted and non-infarcted myocardium through cardiac myocyte apoptosis, hypertrophy and myocardial angiogenesis. This review is focused on the expression of OPN in the heart post MI and its role in various phases of infarct healing.

The delivery of superoxide dismutase encapsulated in polyketal microparticles to rat myocardium and protection from myocardial ischemia-reperfusion injury

Oxidative stress is increased in the myocardium following infarction and plays a significant role in death of cardiac myocytes, leading to cardiac dysfunction. Levels of the endogenous antioxidant Cu/Zn-superoxide dismutase (SOD1) decrease following myocardial infarction. While SOD1 gene therapy studies show promise, trials with SOD1 protein have had little success due to poor pharmacokinetics and thus new delivery vehicles are needed. In this work, polyketal particles, a recently developed delivery vehicle, were used to make SOD1-encapsulated-microparticles (PKSOD). Our studies with cultured macrophages demonstrated that PKSOD treatment scavenges both intracellular and extracellular superoxide, suggesting efficient delivery of SOD1 protein to the inside of cells. In a rat model of ischemia/reperfusion (IR) injury, injection of PKSOD, and not free SOD1 or empty particles was able to scavenge IR-induced excess superoxide 3 days following infarction. In addition, only PKSOD treatment significantly reduced myocyte apoptosis. Further, PKSOD treatment was able to improve cardiac function as measured by acute changes in fractional shortening from baseline echocardiography, suggesting that sustained delivery of SOD1 is critical during the early phase of cardiac repair. These data demonstrate that delivery of SOD1 with polyketals is superior to free SOD1 protein therapy and may have potential clinical implications.

Ischemia Activates the ATF6 Branch of the Endoplasmic Reticulum Stress Response

Stresses that perturb the folding of nascent endoplasmic reticulum (ER) proteins activate the ER stress response. Upon ER stress, ER-associated ATF6 is cleaved; the resulting active cytosolic fragment of ATF6 translocates to the nucleus, binds to ER stress response elements (ERSEs), and induces genes, including the ER-targeted chaperone, GRP78. Recent studies showed that nutrient and oxygen starvation during tissue ischemia induce certain ER stress response genes, including GRP78; however, the role of ATF6 in mediating this induction has not been examined. In the current study, simulating ischemia (sI) in a primary cardiac myocyte model system caused a reduction in the level of ER-associated ATF6 with a coordinate increase of ATF6 in nuclear fractions. An ERSE in the GRP78 gene not previously shown to be required for induction by other ER stresses was found to bind ATF6 and to be critical for maximal ischemia-mediated GRP78 promoter induction. Activation of ATF6 and the GRP78 promoter, as well as grp78 mRNA accumulation during sI, were reversed upon simulated reperfusion (sI/R). Moreover, dominant-negative ATF6, or ATF6-targeted miRNA blocked sI-mediated grp78 induction, and the latter increased cardiac myocyte death upon simulated reperfusion, demonstrating critical roles for endogenous ATF6 in ischemia-mediated ER stress activation and cell survival. This is the first study to show that ATF6 is activated by ischemia but inactivated upon reperfusion, suggesting that it may play a role in the induction of ER stress response genes during ischemia that could have a preconditioning effect on cell survival during reperfusion.

O-GlcNAc signaling attenuates ER stress-induced cardiomyocyte death

We previously demonstrated that the O-linked beta-N-acetylglucosamine (O-GlcNAc) posttranslational modification confers cardioprotection at least partially through mitochondrial-dependent mechanisms, but it remained unclear if O-GlcNAc signaling interfered with other mechanisms of cell death. Because ischemia/hypoxia causes endoplasmic reticulum (ER) stress, we ascertained whether O-GlcNAc signaling could attenuate ER stress-induced cell death per se. Before induction of ER stress (with tunicamycin or brefeldin A), we adenovirally overexpressed O-GlcNAc transferase (AdOGT) or pharmacologically inhibited O-GlcNAcase [via O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate] to augment O-GlcNAc levels or adenovirally overexpressed O-GlcNAcase to reduce O-GlcNAc levels. AdOGT significantly (P < 0.05) attenuated the activation of the maladaptive arm of the unfolded protein response [according to C/EBP homologous protein (CHOP) activation] and cardiomyocyte death (reflected by percent propidium iodide positivity). Moreover, pharmacological inhibition of O-GlcNAcase significantly (P < 0.05) mitigated ER stress-induced CHOP activation and cardiac myocyte death. Interestingly, overexpression of GCA did not alter ER stress markers but exacerbated brefeldin A-induced cardiomyocyte death. We conclude that enhanced O-GlcNAc signaling represents a partially proadaptive response to reduce ER stress-induced cell death. These results provide new insights into a possible interaction between O-GlcNAc signaling and ER stress and may partially explain a mechanism of O-GlcNAc-mediated cardioprotection.

Apoptosis and Proliferation of Cardiomyocytes and Interstitial Mononuclear Cells: Association With Rejection and Macrophage Infiltration

Previous studies have noted that acute rejection episodes (AREs) may lead to loss of cardiomyocytes in transplanted hearts. The aim of this study was twofold; first, to assess the degree of apoptotic cells and to compute the proliferation index of cardiomyocytes and mononuclear interstitial infiltrates in cardiac allografts. Second, we sought to determine whether apoptosis involved in AREs was associated with macrophage infiltration. Among 28 endomyocardial biopsies, 18 showed AREs and the remaining 10 biopsies, nonspecific changes, the control group. All biopsies were immunostained with Ki-67 and CD68 antibodies. Apoptotic cells were counted using the terminal deoxyncleotidyl transferase dUTP nick end labeling method. Apoptotic death of cardiac myocytes and interstitial mononuclear cells was significantly greater in cases of allograft rejection compared with the control group (P < .05). In addition, compared to the control group, ARE cases showed a greater proliferation index of cardiac myocytes and interstitial cells (P < .05). Macrophage infiltration was significantly greater in ARE cases and macrophage infiltration showed a linear association with both apoptosis and proliferation of myocytes and interstitial cells (P < .001). In conclusion, we verified the presence of apoptotic cell death during acute rejection in heart transplants. Apoptotic cell death was significant among interstitial cells but it was less among cardiac myocytes. Macrophage infiltration had a great influence on apoptotic cell death of myocytes and interstitial cells.

The cannabinoid receptor type 2 promotes cardiac myocyte and fibroblast survival and protects against ischemia/reperfusion‐induced cardiomyopathy

Post-myocardial infarction (MI) heart failure is a major public health problem in Western countries and results from ischemia/reperfusion (IR)-induced cell death, remodeling, and contractile dysfunction. Ex vivo studies have demonstrated the cardioprotective anti-inflammatory effect of the cannabinoid type 2 (CB2) receptor agonists within hours after IR. Herein, we evaluated the in vivo effect of CB2 receptors on IR-induced cell death, fibrosis, and cardiac dysfunction and investigated the target role of cardiac myocytes and fibroblasts. The infarct size was increased 24 h after IR in CB2(-/-) vs. wild-type (WT) hearts and decreased when WT hearts were injected with the CB2 agonist JWH133 (3 mg/kg) at reperfusion. Compared with WT hearts, CB2(-/-) hearts showed widespread injury 3 d after IR, with enhanced apoptosis and remodeling affecting the remote myocardium. Finally, CB2(-/-) hearts exhibited exacerbated fibrosis, associated with left ventricular dysfunction 4 wk after IR, whereas their WT counterparts recovered normal function. Cardiac myocytes and fibroblasts isolated from CB2(-/-) hearts displayed a higher H(2)O(2)-induced death than WT cells, whereas 1 microM JWH133 triggered survival effects. Furthermore, H(2)O(2)-induced myofibroblast activation was increased in CB2(-/-) fibroblasts but decreased in 1 microM JWH133-treated WT fibroblasts, compared with that in WT cells. Therefore, CB2 receptor activation may protect against post-IR heart failure through direct inhibition of cardiac myocyte and fibroblast death and prevention of myofibroblast activation.

Sphingomyelinases: their regulation and roles in cardiovascular pathophysiology

Sphingomyelinases (SMases) hydrolyse sphingomyelin, releasing ceramide and creating a cascade of bioactive lipids. These lipids include sphingosine and sphingosine-1-phosphate, all of which have a specific signalling capacity. Sphingomyelinase activation occurs in different cardiovascular system cell types, namely cardiac myocytes, endothelial and vascular smooth muscle cells, mediating cell proliferation, cell death, and contraction of cardiac and vascular myocytes. Three main types of SMases contribute to cardiovascular physiology: the lysosomal and secreted acidic SMases (L- and S-ASMases, respectively) and the membrane neutral SMase (NSMase). These three enzymes have common activators, including ischaemia/reperfusion stress and proinflammatory cytokines, but they differ in their enzymatic properties and subcellular locations that determine the final effect of enzyme activation. This review focuses on the recent advances in the understanding of ASMase and NSMase pathways and their specific contribution to cardiovascular pathophysiology. Current knowledge indicates that the inhibitors of the different SMase types are potential tools for the treatment of cardiovascular diseases. Acid SMase inhibitors could be tools against post-ischaemia reperfusion injury and in the treatment of atherosclerosis. Neutral SMase inhibitors could be tools for the treatment of atherosclerosis, heart failure, and age-related decline in vasomotion. However, the design of bioavailable and more specific SMase-type inhibitors remains a challenge.

Regulation of Bcl-2 phosphorylation in response to oxidative stress in cardiac myocytes

Oxidative stress promotes cardiac myocyte death and has been implicated in the pathogenesis of many cardiovascular diseases. Bcl-2 family proteins are key regulators of the apoptotic response, while their functions can be regulated by post-transcriptional modifications including phosphorylation, dimerization or proteolytic cleavage. This study used adult cardiac myocytes to test the hypothesis that activation of specific kinase signalling pathways by oxidative stress may modulate either the expression or the phosphorylation of Bcl-2, with the resulting effect of a decrease or increase in its anti-apoptotic function. Stimulation of cardiac myocytes with 0.2 mM H2O2, which induces apoptosis, resulted in a marked down-regulation of Bcl-2 protein simultaneously with an increase in its phosphorylation. Inhibition of p38-MAPK resulted in attenuation of Bcl-2 phosphorylation, whereas inhibition of ERK1/2, JNKs or PI-3-K had no effect. These data suggest that activation of p38 MAPK by oxidative stress results in the phosphorylation and degradation of Bcl-2 and the inactivation of its anti-apoptotic activity.

Cardiac reanimation: targeting cardiomyocyte death by BNIP3 and NIX/BNIP3L

Programmed cardiac myocyte death contributes to pathological ventricular remodeling and the progression of myocardial infarction or pressure overload hypertrophy to dilated cardiomyopathy. Recent work has identified importance of stress-mediated transcriptional induction of BNIP3 (BCL2 and 19-kDa interacting protein-3) and NIX/BNIP3L in cardiac remodeling. Here, the regulatory mechanisms for these two factors in the heart and their effects on programmed cardiomyocyte death are reviewed, with a focus on information derived from studies using mouse models of cardiac BNIP3 and NIX/BNIP3L overexpression and gene ablation.

Abstract 1417: Stem Cell Based Gene Transfer of GATA4 Fused with Cell Penetrating Peptide VP22 for Cardiac Repair

We have recently demonstrated that GATA4 fused with cell penetrating peptide VP22 is an efficacious strategy for delivering a cardiac transcription factor to the myocardium in ischemic cardiomyopathy. We have similarly demonstrated that the delivery of SDF-1 to the heart soon after myocardial infarction (MI) leads to stem cell recruitment and preservation of cardiac myocytes. We hypothesized that by combining VP22:GATA4 and SDF-1 delivery to the myocardium we could recruit stem cells to the heart and force their differentiation following MI. We used the infusion of genetically modified mesenchymal stem cells (MSC) to deliver the SDF-1 and VP22:GATA4 to the heart after MI. MSCs isolated from bone marrow and stably transduced with Lentiviral VP22:GATA4 or SDF-1 were infused through tail vein one week after LAD ligation in Lewis rat model. Experimental groups consisted of Saline, Control MSC, SDF-1 MSC, VP22:GATA4 MSC or combined VP22:GATA4 and SDF-1 MSC. In each situation 2 million MSC were infused, but no more than 1 million of any specific genetically modified MSC was infused. Ejection fraction was quantified by echocardgraphy 2 and 6 weeks after cell infusion. At 2 w after cell infusion we observed a 23 ± 1% and 40 ± 5% improvements in ejection fraction of MSC and SDF-1 groups relative to saline controls. We observed a 23 ± 4% decline in function in the VP22:GATA4 group and no improvement in the combination group. At 6 weeks after cell infusion, we observed no significant improvements in the MSC group and a 47 ± 10% and a 20 ± 4% improvements in the SDF-1 and combo groups, the function in the VP22:GATA4 group improved to have no significant difference compared to saline control. Intravenous infusion of MSC can be used to deliver natural and chimeric proteins to the myocardial tissue following MI. The initial decline in function in those animals that received VP22:GATA4 expressing MSC suggest that forced induction of cardiac differentiation soon after MI may have detrimental effects on myocardial tissue leading to increased cardiac myocyte death and adverse remodeling. These findings have implications in strategies being developed to induce myocardial regeneration soon after MI.