Recommendations for successful training on methods of delivery of biologics for cardiac regeneration: a report of the International Society for Cardiovascular Translational Research.

The field of myocardial regeneration (angiogenesis and myogenesis) might prove to play an important role in the future management of cardiovascular disease. Stem cells are currently undergoing testing in Phase I and Phase II clinical trials. Methods of delivery will affect the outcome of such therapies, perhaps significantly. This document provides suggested guidance in 4 methods of delivery: endocardial, intracoronary, coronary sinus, and epicardial.

Heart and skeletal muscle are targets of dengue virus infection.

BACKGROUND: Dengue fever is one of the most significant re-emerging tropical diseases, despite our expanding knowledge of the disease, viral tropism is still not known to target heart tissues or muscle. METHODS: A prospective pediatric clinical cohort of 102 dengue hemorrhagic fever patients from Colombia, South America, was followed for 1 year. Clinical diagnosis of myocarditis was routinely performed. Electrocardiograph and echocardiograph analysis were performed to confirm those cases. Immunohistochemistry for detection of dengue virus and inflammatory markers was performed on autopsied heart tissue. In vitro studies of human striated skeletal fibers (myotubes) infected with dengue virus were used as a model for myocyte infection. Measurements of intracellular Ca2+ concentration as well as immunodetection of dengue virus and inflammation markers in infected myotubes were performed. RESULTS: Eleven children with dengue hemorrhagic fever presented with symptoms of myocarditis. Widespread viral infection of the heart, myocardial endothelium, and cardiomyocytes, accompanied by inflammation was observed in 1 fatal case. Immunofluorescence confocal microscopy showed that myotubes were infected by dengue virus and had increased expression of the inflammatory genes and protein IP-10. The infected myotubes also had increases in intracellular Ca2+ concentration. CONCLUSIONS: Vigorous infection of heart tissues in vivo and striated skeletal cells in vitro are demonstrated. Derangements of Ca2+ storage in the infected cells may directly contribute to the presentation of myocarditis in pediatric patients.

Stem cell therapy for the treatment of acute myocardial infarction.

The last decade has been accompanied by great optimism and interest in the concept of cell or tissue regeneration in the postinfarction myocardium. However, despite the promise, progress was slow. Data derived from multiple controlled studies in hundreds of patients postmyocardial infarction have shown hints of potential benefit but not of the magnitude anticipated. The complexity and hurdles to repair the damaged myocardium have been more daunting than originally estimated. In the end analysis, progress will be made incrementally. The promise for cell therapy continues to be significant, but so are the challenges ahead. This article takes a fresh look at the progress in myocardial regeneration. The authors look at the postmyocardial environment for cues that may guide repair and they look closely at the clinical data for evidence of cardiac regeneration. This evidence is used for suggestions on how to best proceed with future work.

Efficient dengue virus (DENV) infection of human muscle satellite cells upregulates type I interferon response genes and differentially modulates MHC I expression on bystander and DENV-infected cells.

Dengue virus (DENV) is a mosquito-borne flavivirus that causes an acute febrile disease in humans, characterized by musculoskeletal pain, headache, rash and leukopenia. The cause of myalgia during DENV infection is still unknown. To determine whether DENV can infect primary muscle cells, human muscle satellite cells were exposed to DENV in vitro. The results demonstrated for the first time high-efficiency infection and replication of DENV in human primary muscle satellite cells. Changes in global gene expression were also examined in these cells following DENV infection using Affymetrix GeneChip analysis. The differentially regulated genes belonged to two main functional categories: cell growth and development, and antiviral type I interferon (IFN) response genes. Increased expression of the type I IFN response genes for tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), melanoma-derived antigen 5 (MDA-5), IFN-gamma-inducible protein 10 (IP-10), galectin 3 soluble binding protein (LGals3BP) and IFN response factor 7 (IRF7) was confirmed by quantitative RT-PCR. Furthermore, higher levels of cell-surface-bound intracellular adhesion molecule-1 (ICAM-1) and soluble ICAM-1 in the cell-culture medium were detected following DENV infection. However, DENV infection impaired the ability of the infected cells in the culture medium to upregulate cell-surface expression of MHC I molecules, suggesting a possible mechanism of immune evasion by DENV. The findings of this study warrant further clinical research to identify whether muscle cells are targets for DENV infection during the acute stage of the disease in vivo.

Stem cells and cardiac repair: a critical analysis.

Utilizing stem cells to repair the damaged heart has seen an intense amount of activity over the last 5 years or so. There are currently multiple clinical studies in progress to test the efficacy of various different cell therapy approaches for the repair of damaged myocardium that were only just beginning to be tested in preclinical animal studies a few years earlier. This rapid transition from preclinical to clinical testing is striking and is not typical of the customary timeframe for the progress of a therapy from bench-to-bedside. Doubtless, there will be many more trials to follow in the upcoming years. With the plethora of trials and cell alternatives, there has come not only great enthusiasm for the potential of the therapy, but also great confusion about what has been achieved. Cell therapy has the potential to do what no drug can: regenerate and replace damaged tissue with healthy tissue. Drugs may be effective at slowing the progression of heart failure, but none can stop or reverse the process. However, tissue repair is not a simple process, although the idea on its surface is quite simple. Understanding cells, the signals that they respond to, and the keys to appropriate survival and tissue formation are orders of magnitude more complicated than understanding the pathways targeted by most drugs. Drugs and their metabolites can be monitored, quantified, and their effects correlated to circulating levels in the body. Not so for most cell therapies. It is quite difficult to measure cell survival except through ex vivo techniques like histological analysis of the target organ. This makes the emphasis on preclinical research all the more important because it is only in the animal studies that research has the opportunity to readily harvest the target tissues and perform the detailed analyses of what has happened with the cells. This need for detailed and usually time-intensive research in animal studies stands in contrast to the rapidity with which therapies have progressed to the clinic. It is now becoming clear through a number of notable examples that progress to the clinic may have occurred too quickly, before adequate testing and independent verification of results could be completed (Check, Nature 446:485-486, 2007; Chien, J Clin Investig 116:1838-1840, 2006; Giles, Nature 442:344-347, 2006). Broad reproducibility and transfer of results from one lab to another has been and always will be essential for the successful application of any cell therapy. So, what is the prognosis for cell therapy to repair heart damage? Will there be an approved cell therapy, or multiple ones, or will it require combinations of more than one cell type to be successful? These are questions often asked. The answers are difficult to know and even more difficult to predict because there are so many variables associated with cell-based therapies. There is much about the biology of cell systems that we still do not understand. Much of the pluripotency or transdifferentiation phenomena (see below) being observed go against accepted and well-tested principles for cell development and fate choice, and has caused a reevaluation of long-accepted theories. Clearly, new pathways for tissue repair and regeneration have been uncovered, but will these new pathways be sufficient to effect significant tissue repair and regeneration? Despite the false starts so far, there is the strong likelihood one or possibly multiple cell therapies will succeed. Clearly, important information has been gained, which should better guide the field to achieving success. When there is the successful verification in patients of a cell therapy, there will be an explosion of technological advances around the approach(es) that succeed. Whatever cells get approved accompanying them will be: more effective delivery methods; growth and storage methods; combination therapies, mixes of cells or cells + gene therapies; combinations with biomaterials and technologies for immune protection, allowing allografting. There are many parallel paths of technology development waiting to be brought together once there is an effective cellular approach. The coming years will no doubt bring some exciting developments.

Correlation of autologous skeletal myoblast survival with changes in left ventricular remodeling in dilated ischemic heart failure.

OBJECTIVES: The effect of autologous skeletal myoblast transplantation has not been rigorously studied in the setting of end-stage ischemic heart failure free of concomitant coronary revascularization. The aims of the present study were to determine autologous skeletal myoblast survival and its effects on left ventricular function and remodeling in sheep with dilated ischemic heart failure. METHODS: Ischemic heart failure (left ventricular ejection fraction, 30% +/- 2%; left ventricular end-systolic volume index, 82 +/- 9 mL/m2) was created in sheep (n = 11) with serial left circumflex coronary artery microembolizations. Instruments were inserted for the long-term determination of left ventricular global and regional dimensions, hemodynamics, and pressure-volume analysis after autologous skeletal myoblast transplantation (approximately 3.0 x 10(8) myoblasts; heart failure plus autologous skeletal myoblast group, n = 5) or without (heart failure-control group, n = 6). Measurements were performed in conscious animals. RESULTS: Autologous skeletal myoblast-derived skeletal muscle was found in all injected animals at 6 weeks. In ischemic heart failure, autologous skeletal myoblast cardiomyoplasty failed to improve systolic (left ventricular ejection fraction, 29% +/- 4%; dP/dT(max), 2863 +/- 152 mm Hg/s; end-systolic elastance, 1.6 +/- 0.22) or diastolic (left ventricular end-diastolic pressure, 21 +/- 2 mm Hg; time constant of relaxation (Tau), 34 +/- 4 ms; dP/dT(min), -1880 +/- 68 mm Hg/s) function. There was, however, attenuation in the left ventricular dilatation after autologous skeletal myoblast transplantation (change in end-systolic volume index, 14% +/- 4% vs 32% +/- 6%; P < .05). The effects of autologous skeletal myoblast-derived skeletal muscle were exclusive to the left ventricular short-axis dimension and dependent on autologous skeletal myoblast survival (R2 = 0.59, P = .006, n = 11). CONCLUSIONS: Autologous skeletal cardiomyoplasty was able to attenuate left ventricular remodeling in sheep with end-stage ischemic heart failure.

An overview of myoblast transplantation for myocardial regeneration.

Regenerative medicine represents a new frontier in treatment of disease, particularly cardiovascular disease. The contractile elements of the heart, cardiomyocytes, lack the capacity for any postnatal proliferation or regeneration. Therefore, repair of heart damage can be achieved only by manipulating cardiomyocytes to regrow or by introducing exogenous cells with the capacity to restore function to the myocardium. Many attempts have been made with various cell types to repair the damaged myocardium. We will present here a summary of some of those studies and also present in detail studies utilizing a promising, near-term, and practical source of cells for treatment of heart disease: autologous skeletal myoblasts.

Cell therapy for stroke.

Increasing experimental evidence suggests that cell transplantation can enhance recovery from stroke in animal models of focal cerebral ischemia. Clinical trials have been investigating the effects of a human immortalized neuronal cell line and porcine fetal neurons in stroke victims with persistent and stable deficits. Preclinical studies are focusing on the effects of human stem cells from various sources including brain, bone marrow, umbilical cord, and adipose tissue. This review presents an overview of preclinical and clinical studies on cell therapy for stroke. We emphasize the current, limited knowledge about the biology of implant sources and discuss special conditions in stroke that will impact the potential success of neurotransplantation in clinical trials.

Autologous skeletal myoblasts transplanted to ischemia-damaged myocardium in humans. Histological analysis of cell survival and differentiation.

OBJECTIVES: We report histological analysis of hearts from patients with end-stage heart disease who were transplanted with autologous skeletal myoblasts concurrent with left ventricular assist device (LVAD) implantation. BACKGROUND: Autologous skeletal myoblast transplantation is under investigation as a means to repair infarcted myocardium. To date, there is only indirect evidence to suggest survival of skeletal muscle in humans. METHODS: Five patients (all male; median age 60 years) with ischemic cardiomyopathy, refractory heart failure, and listed for heart transplantation underwent muscle biopsy from the quadriceps muscle. The muscle specimen was shipped to a cell isolation facility where myoblasts were isolated and grown. Patients received a transplant of 300 million cells concomitant with LVAD implantation. Four patients underwent LVAD explant after 68, 91, 141, and 191 days of LVAD support (three transplant, one LVAD death), respectively. One patient remains alive on LVAD support awaiting heart transplantation. RESULTS: Skeletal muscle cell survival and differentiation into mature myofibers were directly demonstrated in scarred myocardium from three of the four explanted hearts using an antibody against skeletal muscle-specific myosin heavy chain. An increase in small vessel formation was observed in one of three patients at the site of surviving myotubes, but not in adjacent tissue devoid of engrafted cells. CONCLUSIONS: These findings represent demonstration of autologous myoblast cell survival in human heart. The implanted skeletal myoblasts formed viable grafts in heavily scarred human myocardial tissue. These results establish the feasibility of myoblast transplants for myocardial repair in humans.

Cell transplantation for stroke.

Cell transplantation has emerged as an experimental approach to restore brain function after stroke. Various cell types including porcine fetal cells, stem cells, immortalized cell lines, and marrow stromal cells are under investigation in experimental and clinical stroke trials. This review discusses the unique advantages and limitations of the different graft sources and emphasizes the current, limited knowledge about their biology. The survival, integration, and efficacy of neural transplants in stroke patients will depend on the type, severity, chronicity, adequacy of circulation, and location of the stroke lesion.