Overexpression of TIMP-1 in Embryonic Stem Cells Attenuates Adverse Cardiac Remodeling Following Myocardial Infarction

Transplanted embryonic stem (ES) cells, following myocardial infarction (MI), contribute to limited cardiac repair and regeneration with improved function. Therefore. novel strategies are still needed to understand the effects of genetically modified transplanted stem cells on cardiac remodeling. The present study evaluates whether transplanted mouse ES cells overexpressing TIMP-1, an antiapoptotic and antifibrotic protein. can enhance cardiac myocyte differentiation, inhibit native cardiac myocyte apoptosis, reduce fibrosis, and improve cardiac function in the infarcted myocardium. MI was produced in C57BL/6 mice by coronary artery ligation. TIMP-1-ES cells, ES cells, or culture medium (control) were transplanted into the peri-infarct region of the heart. Immunofluorescence, TUNEL staining, caspase-3 activity. ELISAs, histology, and echocardiography were used to identify newly differentiated cardiac myocytes and assess apoptosis, fibrosis, and heart function. Two weeks post-MI, significantly (p \u3c 0.05) enhanced engraftment and cardiac myocyte differentiation was observed in TIMP-1-ES cell-transplanted hearts compared with hearts transplanted with ES cells and control. Hearts transplanted with TIMP-1-ES cells demonstrated a reduction in apoptosis as well as an increase (p \u3c 0.05) in p-Akt activity compared with ES cells or culture media controls. Infarct size and interstitial and vascular fibrosis were significantly (p \u3c 0.05) decreased in the TIMP-1-ES cell group compared to controls. Furthermore. MMP-9. a key profibrotic protein, was significantly (p \u3c 0.01) reduced following TIMP-1-ES cell transplantation. Echocardiography data showed fractional shortening and ejection fraction were significantly (p \u3c 0.05) improved in the TIMP-1-ES cell group compared with respective controls. Our data suggest that transplanted ES cells overexpressing TIMP-1 attenuate adverse myocardial remodeling and improve cardiac function compared with ES cells that may have therapeutic potential in regenerative medicine

Genetically Modified Es Cells Enhance Cardiac Repair And Regeneration In The Infarcted Heart

Transplanted embryonic stem (ES) cells following myocardial infarction (MI) contribute to limited cardiac repair and regeneration with improved function. Therefore novel strategies are still needed to enhance the efficacy by which ES cells differentiate into cardiac cell types and inhibit adverse remodeling in the infarcted myocardium. Our studies evaluate whether genetic manipulation of transplanted ES cells employing miR- 1, a pro-cardiac microRNA, and TIMP-1, an anti-apoptotic and anti-fibrotic protein, will enhance cardiac myocyte differentiation, inhibit native cardiac apoptosis, and reduce fibrosis in the infarcted myocardium. Furthermore, we assess levels of associated pro- (caspase-3, PTEN) and anti-(Akt) apoptotic proteins as well as a pro-fibrotic protein (MMP-9) in the post-MI and cell transplanted heart. microRNAs (miRs) have emerged as critical regulators of various physiological processes including development, differentiation, metabolism, and death. Indeed, miR- 1 plays an integral role in early cardiac development in Drosophila and mice as well as mediates differentiation of cardiac myocytes in vitro. To that end, we generated ES cells overexpressing miR-1 (miR-1-ES cells), transplanted them into the infarcted myocardium, and evaluated their impact on cardiac myocyte differentiation, myocardial repair, and left ventricular dysfunction post-MI. We provide evidence demonstrating enhanced cardiac myocyte commitment of transplanted miR-1-ES cells in the mouse infarcted heart as compared to ES cell and culture media transplanted hearts. Assessment of apoptosis revealed overexpression of miR-1 in transplanted ES cells protected host myocardium from MI-induced apoptosis through activation of p-Akt and inhibition of caspase-3, PTEN, and superoxide anion production. A significant reduction iv in interstitial and vascular fibrosis was quantified in miR-1-ES and ES cell transplanted groups compared with control MI. However, no statistical significance between miR-1- ES cell and ES cell groups was observed. Finally mice receiving miR-1-ES cell transplantation post-MI had significantly improved heart function compared with respective controls. Our data suggests miR-1 drives cardiac myocyte differentiation from transplanted ES cells and inhibits apoptosis post-MI ultimately giving rise to enhanced cardiac repair, regeneration, and function. Next, we assessed the role of miR-1-ES cells in a chronic model of MI as research has shown that apoptosis occurs not only hours but months following ischemia. 4 weeks following transplantation into the infarcted myocardium, we provide evidence demonstrating reduced cardiac apoptosis in miR-1-ES cell transplanted hearts compared to respective controls. Moreover, we show significant elevation of p-Akt levels and diminished PTEN levels in hearts transplanted with miR-1-ES cells as determined by enzyme-linked immunoassays. Finally, using echocardiography, we reveal mice receiving miR-1-ES cell transplantation post-MI had significantly improved cardiac function compared with animals transplanted with ES cell and culture media. Our data suggests that miR-1, when overexpressed in transplanted ES cells, has the capacity to inhibit apoptosis long term while attenuating contractility loss. In addition to enhancing cardiac-specific donor cell differentiation, improving the efficacy by which stem cells promote cell survival and repair in the host myocardium is imperative in the pursuit of refining and optimizing stem cell therapy. To that end, we overexpressed TIMP-1, an endogenous inhibitor of apoptosis and fibrosis, in ES cells (TIMP-1-ES cells), transplanted them into infarcted myocardium, and evaluated their v impact on adverse cardiac remodeling. Immunofluorescence, TUNEL staining, caspase-3 activity, ELISAs, histology, and echocardiography were used to assess apoptosis, fibrosis, and heart function. Hearts transplanted with TIMP-1-ES cells demonstrated a reduction in apoptosis as well as an increase in p-Akt activity compared with ES cells or culture media controls. Interstitial and vascular fibrosis was significantly decreased in the TIMP-1-ES cell group compared to controls. Furthermore, MMP-9, a key pro-fibrotic protein, was significantly reduced following TIMP-1-ES cell transplantation. Echocardiography data showed fractional shortening and ejection fraction were significantly improved in the TIMP-1-ES cell group compared with respective controls. Our data suggest that transplanted ES cells overexpressing TIMP- 1 attenuate adverse myocardial remodeling and improve cardiac function compared with ES cells. Overall, our data suggest that genetic manipulation of ES cells following transplantation in the infarcted heart enhances cardiac myocyte differentiation, inhibits apoptosis and fibrosis as well as improves cardiac function

Fibroblast Growth Factor-9 Enhances M2 Macrophage Differentiation and Attenuates Adverse Cardiac Remodeling in the Infarcted Diabetic Heart

Inflammation has been implicated as a perpetrator of diabetes and its associated complications. Monocytes, key mediators of inflammation, differentiate into pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages upon infiltration of damaged tissue. However, the inflammatory cell types, which propagate diabetes progression and consequential adverse disorders, remain unclear. The current study was undertaken to assess monocyte infiltration and the role of fibroblast growth factor-9 (FGF-9) on monocyte to macrophage differentiation and cardioprotection in the diabetic infarcted heart. Db/db diabetic mice were assigned to sham, myocardial infarction (MI), and MI+FGF-9 groups. MI was induced by permanent coronary artery ligation and animals were subjected to 2D transthoracic echocardiography two weeks post-surgery. Immunohistochemical and immunoassay results from heart samples collected suggest significantly increased infiltration of monocytes (Mean +/- SEM; MI: 2.02% +/- 0.23% vs. Sham 0.75% +/- 0.07%; p \u3c 0.05) and associated pro-inflammatory cytokines (TNF-alpha, MCP-1, and IL-6), adverse cardiac remodeling (Mean +/- SEM; MI: 33% +/- 3.04% vs. Sham 2.2% +/- 0.33%; p \u3c 0.05), and left ventricular dysfunction (Mean +/- SEM; MI: 35.4% +/- 1.25% vs. Sham 49.19% +/- 1.07%; p \u3c 0.05) in the MI group. Importantly, treatment of diabetic infarcted myocardium with FGF-9 resulted in significantly decreased monocyte infiltration (Mean +/- SEM; MI+FGF-9: 1.39% +/- 0.1% vs. MI: 2.02% +/- 0.23%; p \u3c 0.05), increased M2 macrophage differentiation (Mean +/- SEM; MI+FGF-9: 4.82% +/- 0.86% vs. MI: 0.85% +/- 0.3%; p \u3c 0.05) and associated anti-inflammatory cytokines (IL-10 and IL-1RA), reduced adverse remodeling (Mean +/- SEM; MI+FGF-9: 11.59% +/- 1.2% vs. MI: 33% +/- 3.04%; p \u3c 0.05), and improved cardiac function (Fractional shortening, Mean +/- SEM; MI+FGF-9: 41.51% +/- 1.68% vs. MI: 35.4% +/- 1.25%; p \u3c 0.05). In conclusion, our data suggest FGF-9 possesses novel therapeutic potential in its ability to mediate monocyte to M2 differentiation and confer cardiac protection in the post-MI diabetic heart

Microrna-1 Transfected Embryonic Stem Cells Enhance Cardiac Myocyte Differentiation And Inhibit Apoptosis By Modulating The Pten/Akt Pathway In The Infarcted Heart

MicroRNAs (miRs) have emerged as critical modulators of various physiological processes including stem cell differentiation. Indeed, miR-1 has been reported to play an integral role in the regulation of cardiac muscle progenitor cell differentiation. However, whether overexpression of miR-1 in embryonic stem (ES) cells (miR-1-ES cells) will enhance cardiac myocyte differentiation following transplantation into the infarcted myocardium is unknown. In the present study, myocardial infarction (MI) was produced in C57BL/6 mice by left anterior descending artery ligation. miR-1-ES cells, ES cells, or culture medium (control) was transplanted into the border zone of the infarcted heart, and 2 wk post-MI, cardiac myocyte differentiation, adverse ventricular remodeling, and cardiac function were assessed. We provide evidence demonstrating enhanced cardiac myocyte commitment of transplanted miR-1-ES cells in the mouse infarcted heart as compared with ES cells. Assessment of apoptosis revealed that overexpression of miR-1 in transplanted ES cells protected host myocardium from MI-induced apoptosis through activation of p-AKT and inhibition of caspase-3, phosphatase and tensin homolog, and superoxide production. A significant reduction in interstitial and vascular fibrosis was quantified in miR-1-ES cell and ES cell transplanted groups compared with control MI. However, no statistical significance between miR-1-ES cell and ES cell groups was observed. Finally, mice receiving miR-1-ES cell transplantation post-MI had significantly improved heart function compared with respective controls (P \u3c 0.05). Our data suggest miR-1 drives cardiac myocyte differentiation from transplanted ES cells and inhibits apoptosis post-MI, ultimately giving rise to enhanced cardiac repair, regeneration, and function. © 2011 the American Physiological Society

Es Cells Overexpressing Microrna-1 Attenuate Apoptosis In The Injured Myocardium

MicroRNAs (miRs) are small, single-stranded, noncoding RNA\u27s involved in post-transcriptional negative gene regulation. Recent investigations have underscored the integral role of miRs in various biological processes including innate immunity, cell-cycle regulation, metabolism, differentiation, and cell death. In the present study, we overexpressed miR-1, a muscle-specific miR, in embryonic stem cells (miR-1-ES cells), transplanted them into the infarcted myocardium, and evaluated their impact on cardiac apoptosis and function. We provide evidence demonstrating reduced apoptosis following transplantation of miR-1-ES cells 4 weeks post-myocardial infarction as compared to respective controls assessed by TUNEL staining and a capsase-3 activity assay. Moreover, we show significant elevation in p-Akt levels and diminished PTEN levels in hearts transplanted with miR-1-ES cells as determined by enzyme-linked immunoassays. Finally, using echocardiography, we reveal mice receiving miR-1-ES cell transplantation post-myocardial infarction had significantly improved fractional shortening and ejection fraction compared with respective controls. Our data suggest transplanted miR-1-ES cells inhibit apoptosis, mediated through the PTEN/Akt pathway, leading to improved cardiac function in the infarcted myocardium. © Springer Science+Business Media, LLC. 2011

Stem Cells In The Diabetic Infarcted Heart

Diabetes mellitus is one of the leading causes of death, and the majority of these deaths are associated with cardiovascular diseases. Development and progression of myocardial infarction leading to heart failure is much more complex and multifactorial in diabetics compared with non-diabetics. Despite significant advances in pharmacological interventions and surgical techniques, the disease progression leading to diabetic end-stage heart failure remains very high. Recently, cell therapy has gained much attention as an alternative approach to treat various heart diseases. However, transplanted stem cell studies in diabetic animal models are very limited. In this review, we discuss the pathogenesis of the diabetic infarcted heart and the potential of stem cell therapy to repair and regenerate. © 2010 Springer Science+Business Media, LLC

The Neurointensive Care Nursery and Evolving Roles for Nursing

Neonatal neurocritical care is an emerging subspecialty that combines the expertise of critical care medicine and neurology with that of nursing and other providers in an interprofessional team approach to care. Neurocritical care of the neonate has roots in adult and pediatric practice. It has been demonstrated that adults with acute neurologic conditions who are treated in a specialized neurocritical care unit have reduced morbidity and mortality, as well as decreased length of stay, lower costs, and reduced need for neurosurgical procedures. In pediatrics, neurocritical care has focused on various primary and secondary neurologic conditions complicating critical care that also contribute to mortality, morbidity, and duration of hospitalization. However, the concept of neurocritical care as a subspecialty in pediatric practice is still evolving, and evidence demonstrating improved outcomes is lacking. In the neonatal intensive care nursery, neurocritical care is also evolving as a subspecialty concept to address both supportive and preventive care and optimize neurologic outcomes for an at-risk neonatal patient population. To enhance effectiveness of this care approach, nurses must be prepared to appropriately recognize acute changes in neurologic status, implement protocols that specifically address neurologic conditions, and carefully monitor neurologic status to help prevent secondary injury. The complexity of this team approach to brain-focused care has led to the development of a specialized role: the neurocritical care nurse (neonatal intensive care nursery [NICN] nurse). This article will review key concepts related to neonatal neurocritical care and the essential role of nursing. It will also explore the emerging role of the NICN nurse in supporting early recognition and management of at-risk infants in this neonatal subspecialty practice

The Neurointensive Care Nursery and Evolving Roles for Nursing.

Neonatal neurocritical care is an emerging subspecialty that combines the expertise of critical care medicine and neurology with that of nursing and other providers in an interprofessional team approach to care. Neurocritical care of the neonate has roots in adult and pediatric practice. It has been demonstrated that adults with acute neurologic conditions who are treated in a specialized neurocritical care unit have reduced morbidity and mortality, as well as decreased length of stay, lower costs, and reduced need for neurosurgical procedures. In pediatrics, neurocritical care has focused on various primary and secondary neurologic conditions complicating critical care that also contribute to mortality, morbidity, and duration of hospitalization. However, the concept of neurocritical care as a subspecialty in pediatric practice is still evolving, and evidence demonstrating improved outcomes is lacking. In the neonatal intensive care nursery, neurocritical care is also evolving as a subspecialty concept to address both supportive and preventive care and optimize neurologic outcomes for an at-risk neonatal patient population. To enhance effectiveness of this care approach, nurses must be prepared to appropriately recognize acute changes in neurologic status, implement protocols that specifically address neurologic conditions, and carefully monitor neurologic status to help prevent secondary injury. The complexity of this team approach to brain-focused care has led to the development of a specialized role: the neurocritical care nurse (neonatal intensive care nursery [NICN] nurse). This article will review key concepts related to neonatal neurocritical care and the essential role of nursing. It will also explore the emerging role of the NICN nurse in supporting early recognition and management of at-risk infants in this neonatal subspecialty practice