Translational aspects of cardiac cell therapy.

Cell therapy has been intensely studied for over a decade as a potential treatment for ischaemic heart disease. While initial trials using skeletal myoblasts, bone marrow cells and peripheral blood stem cells showed promise in improving cardiac function, benefits were found to be short-lived likely related to limited survival and engraftment of the delivered cells. The discovery of putative cardiac 'progenitor' cells as well as the creation of induced pluripotent stem cells has led to the delivery of cells potentially capable of electromechanical integration into existing tissue. An alternative strategy involving either direct reprogramming of endogenous cardiac fibroblasts or stimulation of resident cardiomyocytes to regenerate new myocytes can potentially overcome the limitations of exogenous cell delivery. Complimentary approaches utilizing combination cell therapy and bioengineering techniques may be necessary to provide the proper milieu for clinically significant regeneration. Clinical trials employing bone marrow cells, mesenchymal stem cells and cardiac progenitor cells have demonstrated safety of catheter based cell delivery, with suggestion of limited improvement in ventricular function and reduction in infarct size. Ongoing trials are investigating potential benefits to outcome such as morbidity and mortality. These and future trials will clarify the optimal cell types and delivery conditions for therapeutic effect

Effects of Polyphenols on Oxidative Stress-Mediated Injury in Cardiomyocytes

Cardiovascular diseases are the main cause of mortality and morbidity in the world. Hypertension, ischemia/reperfusion, diabetes and anti-cancer drugs contribute to heart failure through oxidative and nitrosative stresses which cause cardiomyocytes nuclear and mitochondrial DNA damage, denaturation of intracellular proteins, lipid peroxidation and inflammation. Oxidative or nitrosative stress-mediated injury lead to cardiomyocytes apoptosis or necrosis. The reactive oxygen (ROS) and nitrogen species (RNS) concentration is dependent on their production and on the expression and activity of anti-oxidant enzymes. Polyphenols are a large group of natural compounds ubiquitously expressed in plants, and epidemiological studies have shown associations between a diet rich in polyphenols and the prevention of various ROS-mediated human diseases. Polyphenols reduce cardiomyocytes damage, necrosis, apoptosis, infarct size and improve cardiac function by decreasing oxidative stress-induced production of ROS or RNS. These effects are achieved by the ability of polyphenols to modulate the expression and activity of anti-oxidant enzymes and several signaling pathways involved in cells survival. This report reviews current knowledge on the potential anti-oxidative effects of polyphenols to control the cardiotoxicity induced by ROS and RNS stress

Cell-based gene therapy for mending infarcted hearts

The goal of this study was to analyse the efficiency of a combinatorial cell/growth factor therapy to improve function of infarcted murine hearts. The Insulin-like Growth Factor-1 (IGF-1) isoform, IGF-1Ea, has been shown to reduce scar formation and decrease cell death after MI. The present study utilized P19Cl6-derived, IGF-1Ea over-expressing cardiomyocytes to achieve its goal. The P19Cl6 cells were stably transduced with IGF-1Ea using a lentiviral vector and investigated first in vitro for their feasibility for in vivo cell therapy. The engineered pluripotent cells over-expressing IGF-1Ea survived better to hypoxia-induced injury than the control cells. The cells maintained their pluripotency and efficient differentiation capacity towards ventricular cardiomyocyte lineage, generating large quantities of cardiomyocytes optimal for the transplantation study. The generated cardiomyocytes were functionally active and exhibited a mature phenotype. Transplantation of the cardiomyocytes into allogeneic wild type murine infarcted hearts conferred a tendency for maintenance of function at short-term time point. At long-term however, this effect was lost, returning to the level of the control infarcted hearts. Cell tracing assessment revealed engraftment of both IGF-1Ea- and empty-cells, although the cells failed to couple with the recipient tissue. Scar size and capillary density analyses revealed no significant difference between the cells transplanted compared to the saline treated hearts, corroborating with the long-term functional data. Interestingly, the IGF- 1Ea-cell transplanted hearts expressed significantly higher amount of VEGFa compared to the controls, albeit no change in capillary density. Further investigation revealed that the enhanced VEGFa expression in IGF-1Ea-cells transplanted hearts was associated with reduced hypertrophy, marked by reduced cell cross-sectional area at the border-zone, aSK and bMHC expression compared to the control hearts. Nonetheless, modulation of hypertrophic response and transplantation of IGF-1Ea-cells were not able to confer lasting functional preservation, possibly due to lack of sufficient engraftment and coupling of the transplanted cells

Cell-free Embryonic Stem Cell Extract-mediated Derivation of Multi-potent Stem Cells from NIH3T3 Fibroblasts for Functional and Anatomical Ischemic Tissue Repair

The oocyte-independent generation of multipotent stem cells is one of the goals in regenerative medicine. We report that upon exposure to mouse ES cell (ESC) extracts, reversibly permeabilized NIH3T3 cells undergo de-differentiation followed by stimulus-induced re-differentiation into multiple lineage cell types. Genome-wide expression profiling revealed significant differences between NIH3T3 and ESC-extract treated NIH3T3 cells including re-activation of ESC specific transcripts. Epigenetically, ESC extracts induced CpG de-methylation of Oct4 promoter, hyper-acetylation of histones 3 and 4 and decreased lysine 9 (K-9) dimethylation of histone 3. In mouse models of surgically-induced hind limb ischemia (HLI) or acute myocardial infarction (AMI) transplantation of reprogrammed NIH3T3 cells significantly improved post-injury physiological functions and showed antomical evidence of engraftment and trans-differentiation into skeletal muscle, endothelial cell and cardiomyocytes. These data provide evidence for the generation of functional multi-potent stem like cells from terminally differentiated somatic cells without the introduction of trans-genes or ESC fusion

Stem Cell Therapy: Pieces of the Puzzle

Acute ischemic injury and chronic cardiomyopathies can cause irreversible loss of cardiac tissue leading to heart failure. Cellular therapy offers a new paradigm for treatment of heart disease. Stem cell therapies in animal models show that transplantation of various cell preparations improves ventricular function after injury. The first clinical trials in patients produced some encouraging results, despite limited evidence for the long-term survival of transplanted cells. Ongoing research at the bench and the bedside aims to compare sources of donor cells, test methods of cell delivery, improve myocardial homing, bolster cell survival, and promote cardiomyocyte differentiation. This article reviews progress toward these goals

Protection of organs other than the heart by remote ischemic conditioning

Organ or tissue dysfunction due to acute ischemia–reperfusion injury (IRI) is the leading cause of death and disability worldwide. Acute IRI induces cell injury and death in a wide variety of organs and tissues in a large number of different clinical settings. One novel therapeutic noninvasive intervention, capable of conferring multiorgan protection against acute IRI, is ‘remote ischemic conditioning’ (RIC). This describes an endogenous protective response to acute IRI, which is triggered by the application of one or more brief cycles of nonlethal ischemia and reperfusion to one particular organ or tissue. Originally discovered as a therapeutic strategy for protecting the myocardium against acute IRI, it has been subsequently demonstrated that RIC may confer protection against acute IRI in a number of different noncardiac organs and tissues including the kidneys, lungs, liver, skin flaps, ovaries, intestine, stomach and pancreas. The discovery that RIC can be induced noninvasively by applying the RIC stimulus to the skeletal tissue of the upper or lower limb has facilitated its application to a number of clinical settings in which organs and tissues are at high risk of acute IRI. In this article, we review the experimental studies that have investigated RIC in organs and tissues other than the heart, and we explore the therapeutic potential of RIC in preventing organ and tissue dysfunction induced by acute IRI

Improved method for quantification of regional cardiac function in mice using phase-contrast MRI

Phase-contrast magnetic resonance imaging is a technique that allows for characterization of regional cardiac function and for measuring transmural myocardial velocities in human hearts with high temporal and spatial resolution. The application of this technique (also known as tissue phase mapping) to murine hearts has been very limited so far. The aim of our study was to implement and to optimize tissue phase mapping for a comprehensive assessment of murine transmural wall motion. Baseline values for regional motion patterns in mouse hearts, based on the clinically used American Heart Association's 17-segment model, were established, and a detailed motion analysis of mouse heart for the entire cardiac cycle (including epicardial and endocardial motion patterns) is provided. Black-blood contrast was found to be essential to obtain reproducible velocity encoding. Tissue phase mapping of the mouse heart permits the detailed assessment of regional myocardial velocities. While a proof-of-principle application in a murine ischemia–reperfusion model was performed, future studies are warranted to assess its potential for the investigation of systolic and diastolic functions in genetically and surgically manipulated mouse models of human heart disease. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc

Langendorff’s isolated perfused rat heart technique: a review

The Langendorff’s isolated perfused small mammalian heart represents the optimal compromise in the conflict between the quantity and quality of data that can be acquired from an experimental model versus its clinical relevance, especially in relation to ischemia-reperfusion injury. We analyzed the important recent, as well as standard older articles to highlight the importance of Langendorff’s isolated heart technique using the rat as an experimental animal model. The retrograde perfusion of isolated rat heart preparation is the most commonly used technique in cardiovascular research experiments with many advantages. The longevity of this preparation is one of the main advantages. From the moment an ex vivo preparation is established, it starts to deteriorate and the rate will depend on number of factors such as the skill of the operator, the species of animal, age, initial heart rate, choice and composition of the perfusion fluid, flow rate, presence or absence of various drugs, preload pressure, and the temperature at which the studies are carried out. Recently, various techniques and variables measured have undergone modifications. This review article has attempted to address many of the issues, developments, and applications which will assist investigators to make the best possible use of this experimental model using the rat