Therapeutic application of adipose derived stem cells in acute myocardial infarction: lessons from animal models. Stem Cell Rev Rep. 2014;10:389-398. [PMID: 24577790 DOI: 10.1007/s12015-014-9502-7]

Cardiac Adipose Tissue Contributes to Cardiac Repair: a Review

Cardiac adipose tissue is a metabolically active adipose tissue in close proximity to heart. Recent studies emphasized the benefits of cardiac adipose tissue in heart remodeling, such as reducing infarction size, enhancing neovascularization and regulating immune response, through a series of cellular mechanisms. In the present manuscript, we provide a comprehensive review regarding the role of cardiac adipose tissue in cardiac repair. We focus on different cardiac adipose tissues according to their distinguished anatomical structures. This review summarizes the latest evidence on the relationship between cardiac adipose tissue and cardiac repair. Cardiac adipose tissues (CAT) were systematically reviewed in the current manuscript which focused on the components of CAT, debates about cardiac adipose stem cells and their effect on heart.

Immunomodulatory Effect of Adipose-Derived Stem Cells: The Cutting Edge of Clinical Application

Adipose-derived stem cells (ASCs) represent a promising tool for soft tissue engineering as well as for clinical treatment of inflammatory and autoimmune pathologies. The well-characterized multi-differentiation potential and self-renewal properties of ASCs are coupled with their immunomodulatory ability in providing therapeutic efficacy. Yet, their impact in immune or inflammatory disorders might rely both on cell contact-dependent mechanisms and paracrine effects, resulting in the release of various soluble factors that regulate immune cells functions. Despite the widespread use of ASCs in clinical trials addressing several pathologies, the pathophysiological mechanisms at the basis of their clinical use have been not yet fully investigated. In particular, a thorough analysis of ASC immunomodulatory potential is mandatory. Here we explore such molecular mechanisms involved in ASC immunomodulatory properties, emphasizing the relevance of the milieu composition. We review the potential clinical use of ASC secretome as a mediator for immunomodulation, with a focus on in vitro and in vivo environmental conditions affecting clinical outcome. We describe some potential strategies for optimization of ASCs immunomodulatory capacity in clinical settings, which act either on adult stem cells gene expression and local microenvironment. Finally, we discuss the limitations of both allogeneic and autologous ASC use, highlighting the issues to be fixed in order to significantly improve the efficacy of ASC-based cell therapy.

In Vivo Ultrasound Molecular Imaging of SDF-1 Expression in a Swine Model of Acute Myocardial Infarction

Background: Stem cell therapy of acute myocardial infarction (AMI) is proving to be a promising approach to repair the injured myocardia. The time window for stem cell transplantation is crucial yet difficult to determine since it produces different therapeutic effects at different times after myocardial infarction. Stromal cell-derived factor-1 (SDF- 1) plays a pivotal role in the mobilization, homing, proliferation, and differentiation of transplanted stem cells. Here, by using ultrasound molecular imaging via targeted microbubbles, we determined the dynamic expression of SDF-1 in a swine model of AMI in vivo. Methods: Twenty-four miniswine were randomly selected for the control group and the AMI model group, which underwent ligation of the left anterior descending coronary artery (LAD). The AMI animals were randomly divided into six experimental groups according to the duration of the myocardial infarction. All animals were subjected to ultrasound molecular imaging through injections with targeted microbubbles (T + T group) or nontargeted control microbubbles (T + C group). The values of the myocardial perfusion parameters (A, β, and A × β) were determined using Q-Lab (Philips ultrasound, version 9.0), and the expression level of SDF-1 was analyzed by real-time polymerase chain reaction (RT-PCR). Results: Our results showed that the expression of SDF-1 gradually increased and peaked at 1 week after AMI. The trend is well reflected by ultrasound molecular imaging in the myocardial perfusion parameters. The A, β, and A × β values correlated with SDF-1 in the T + T group (r = 0.887, 0.892, and 0.942; P < 0.05). Regression equations were established for the relationships of the A, β, and A × β values (X) with SDF-1 (Y): Y = 0.699X - 0.6048, Y = 0.4698X + 0.3282, and Y = 0.0945X + 0.6685, respectively (R 2 = 0.772, 0.7957, and 0.8871; P < 0.05). Conclusions: Our finding demonstrated that ultrasound molecular imaging could be used to evaluate the expression dynamics of SDF-1 after AMI.

Harnessing the secretome of adipose-derived stem cells in the treatment of ischemic heart diseases

Adipose-derived stem cells (ASCs) are promising therapeutic cells for ischemic heart diseases, due to the ease and efficiency of acquisition, the potential of myocardial lineage differentiation, and the paracrine effects. Recently, many researchers have claimed that the ASC-based myocardial repair is mainly attributed to its paracrine effects, including the anti-apoptosis, pro-angiogenesis, anti-inflammation effects, and the inhibition of fibrosis, rather than the direct differentiation into cardiovascular lineage cells. However, the usage of ASCs comes with the problems of low cardiac retention and survival after transplantation, like other stem cells, which compromises the effectiveness of the therapy. To overcome these drawbacks, researchers have proposed various strategies for improving survival rate and ensuring sustained paracrine secretion. They also investigated the safety and efficacy of phase I and II clinical trials of ASC-based therapy for cardiovascular diseases. In this review, we will discuss the characterization and paracrine effects of ASCs on myocardial repair, followed by the strategies for stimulating the paracrine secretion of ASCs, and finally their clinical usage.

Perspectives for Clinical Translation of Adipose Stromal/Stem Cells

Adipose stromal/stem cells (ASCs) are an ideal cell type for regenerative medicine applications, as they can easily be harvested from adipose tissue in large quantities. ASCs have excellent proliferation, differentiation, and immunoregulatory capacities that have been demonstrated in numerous studies. Great interest and investment have been placed in efforts to exploit the allogeneic use and immunomodulatory and anti-inflammatory effects of ASCs. However, bridging the gap between in vitro and in vivo studies and moving into clinical practice remain a challenge. For the clinical translation of ASCs, several issues must be considered, including how to characterise such a heterogenic cell population and how to ensure their safety and efficacy. This review explores the different phases of in vitro and preclinical ASC characterisation and describes the development of appropriate potency assays. In addition, good manufacturing practice requirements are discussed, and cell-based medicinal products holding marketing authorisation in the European Union are reviewed. Moreover, the current status of clinical trials applying ASCs and the patent landscape in the field of ASC research are presented. Overall, this review highlights the applicability of ASCs for clinical cell therapies and discusses their potential.

Effect of Cell Seeding Density and Inflammatory Cytokines on Adipose Tissue-Derived Stem Cells: an in Vitro Study

Adipose tissue-derived stem cells (ASCs) are known to be able to promote repair of injured tissue via paracrine factors. However, the effect of cell density and inflammatory cytokines on the paracrine ability of ASCs remains largely unknown. To investigate these effects, ASCs were cultured in 8000 cells/cm², 20,000 cells/cm², 50,000 cells/cm², and 400,000 cells/cm² with and without 10 or 20 ng/ml tumor necrosis factor alpha (TNFα) and 25 or 50 ng/ml interferon gamma (IFNγ). ASC-sheets formed at 400,000 cells/cm² after 48 h of culture. With increasing concentrations of TNFα and IFNγ, ASC-sheets with 400,000 cells/cm² had increased production of angiogenic factors Vascular Endothelial Growth Factor and Fibroblast Growth Factor and decreased expression of pro-inflammatory genes TNFA and Prostaglandin Synthase 2 (PTGS2) compared to lower density ASCs. Moreover, the conditioned medium of ASC-sheets with 400,000 cells/cm² stimulated with the low concentration of TNFα and IFNγ enhanced endothelial cell proliferation and fibroblast migration. These results suggest that a high cell density enhances ASC paracrine function might beneficial for wound repair, especially in pro-inflammatory conditions.

Adipose Tissue-Derived Stem Cells for Myocardial Regeneration

Over the past decade, stem cell therapy has been extensively studied for clinical application for heart diseases. Among various stem cells, adipose tissue-derived stem cell (ADSC) is still an attractive stem cell resource due to its abundance and easy accessibility. In vitro studies showed the multipotent differentiation potentials of ADSC, even differentiation into cardiomyocytes. Many pre-clinical animal studies have also demonstrated promising therapeutic results of ADSC. Furthermore, there were several clinical trials showing the positive results in acute myocardial infarction using ADSC. The present article covers the brief introduction, the suggested therapeutic mechanisms, application methods including cell dose and delivery, and human clinical trials of ADSC for myocardial regeneration.

Novel cardioprotective and regenerative therapies in acute myocardial infarction: a review of recent and ongoing clinical trials

Following the original large-scale randomized trials of aspirin and β-blockade, there have been a number of major advances in pharmacological and mechanical treatments for acute myocardial infarction. Despite this progress, myocardial infarction remains a major global cause of mortality and morbidity, driving a quest for novel treatments in this area. As the understanding of mitochondrial dynamics and the pathophysiology of reperfusion injury has evolved, the last three decades have seen advances in ischemic conditioning, pharmacological and metabolic cardioprotection, as well as biological and stem-cell therapies. The aim of this review is to provide a synopsis of adjunctive cardioprotective and regenerative therapies currently undergoing or entering early clinical trials in the treatment of patients with acute myocardial infarction.

Effects of the intramyocardial implantation of stromal vascular fraction in patients with chronic ischemic cardiomyopathy

BACKGROUND

Stromal vascular fraction (SVF) can easily be obtained from a mini-lipoaspirate procedure of fat tissue. The SVF contains a mixture of cells including ADSCs and growth factors and has been depleted of the adipocyte (fat cell) population. We evaluated the safety and efficacy of administering SVF intra-myocardially into patients with chronic ischemic cardiomyopathy.

METHODS

A total of 28 patients underwent a local tumescent liposuction procedure to remove approximately 60 ml of fat tissue. The fat was separated to isolate the SVF and the cells were delivered into the akinetic myocardial scar region using a transendocardial delivery system (MyoCath(®)) in patients who had experienced a previous myocardial infarct. The subjects were then monitored for adverse events, ejection fraction via echocardiogram and six-minute walk test (6MWT) over a period of 6 months.

RESULTS

The average EF was 29 % at baseline and significantly increased to 35 % at both 3 and 6 months. Patients walked an average of 349 m at baseline and demonstrated a statistically significant improvement at 3 and 6 months' post treatment of more than 80 m.

CONCLUSIONS

Overall, patients were pleased with the treatment results. More importantly, the procedure demonstrated a strong safety profile with no severe adverse events or complications linked to the therapy. Trial registration NCT01502514 Name of registry: http://www.clinicaltrials.gov URL: https://www.clinicaltrials.gov/ct2/show/NCT01502514?term=adipose+cells+heart&rank=4 Date of registration: December 27, 2011 Date of enrollment: January 2012.

Role of platelet-rich plasma in ischemic heart disease: An update on the latest evidence

Myocardial infarction is the most common cause of congestive heart failure. Novel strategies such as directly reprogramming cardiac fibroblasts into cardiomyocytes are an exciting area of investigation for repair of injured myocardial tissue. The ultimate goal is to rebuild functional myocardium by transplanting exogenous stem cells or by activating native stem cells to induce endogenous repair. Cell-based myocardial restoration, however, has not penetrated broad clinical practice yet. Platelet-rich plasma, an autologous fractionation of whole blood containing high concentrations of growth factors, has been shown to safely and effectively enhance healing and angiogenesis primarily by reparative cell signaling. In this review, we collected all recent advances in novel therapies as well as experimental evidence demonstrating the role of platelet-rich plasma in ischemic heart disease, focusing on aspects that might be important for future successful clinical application.

Application of adipose-derived stem cells in heart disease

Therapy with mesenchymal stem cells is one of the promising tools to improve outcomes after myocardial infarction. Adipose-derived stem cells (ASCs) are an ideal source of mesenchymal stem cells due to their abundance and ease of preparation. Studies in animal models of myocardial infarction have demonstrated the ability of injected ASCs to engraft and differentiate into cardiomyocytes and vasculature cells. ASCs secrete a wide array of angiogenic and anti-apoptotic paracrine factors such as vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1. ASCs are capable of enhancing heart function, reducing myocardial infarction, promoting vascularization, and reversing remodeling in the ischemically injured hearts. Furthermore, several ongoing clinical trials using ASCs are producing promising results for heart diseases. This article reviews the isolation, differentiation, immunoregulatory properties, mechanisms of action, animal models, and ongoing clinical trials of ASCs for cardiac disease.