Implantation of a double allogeneic human engineered tissue graft on damaged heart: insights from the PERISCOPE phase I clinical trial.

BACKGROUND: In preclinical studies, the use of double allogeneic grafts has shown promising results in promoting tissue revascularization, reducing infarct size, preventing adverse remodelling and fibrosis, and ultimately enhancing cardiac function. Building upon these findings, the safety of PeriCord, an engineered tissue graft consisting of a decellularised pericardial matrix and umbilical cord Wharton's jelly mesenchymal stromal cells, was evaluated in the PERISCOPE Phase I clinical trial (NCT03798353), marking its first application in human subjects. METHODS: This was a double-blind, single-centre trial that enrolled patients with non-acute myocardial infarction eligible for surgical revascularization. Seven patients were implanted with PeriCord while five served as controls. FINDINGS: Patients who received PeriCord showed no adverse effects during post-operative phase and one-year follow-up. No significant changes in secondary outcomes, such as quality of life or cardiac function, were found in patients who received PeriCord. However, PeriCord did modulate the kinetics of circulating monocytes involved in post-infarction myocardial repair towards non-classical inflammation-resolving macrophages, as well as levels of monocyte chemoattractants and the prognostic marker Meteorin-like in plasma following treatment. INTERPRETATION: In summary, the PeriCord graft has exhibited a safe profile and notable immunomodulatory properties. Nevertheless, further research is required to fully unlock its potential as a platform for managing inflammatory-related pathologies. FUNDING: This work was supported in part by grants from MICINN (SAF2017-84324-C2-1-R); Instituto de Salud Carlos III (ICI19/00039 and Red RICORS-TERAV RD21/0017/0022, and CIBER Cardiovascular CB16/11/00403) as a part of the Plan Nacional de I + D + I, and co-funded by ISCIII-Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER) and AGAUR (2021-SGR-01437).

Preclinical scenario of targeting myocardial fibrosis with chimeric antigen receptor (CAR) immunotherapy.

Fibrosis is present in an important proportion of myocardial disorders. Injury activates cardiac fibroblasts, which deposit excess extracellular matrix, increasing tissue stiffness, impairing cardiac function, and leading to heart failure. Clinical therapies that directly target excessive fibrosis are limited, and more effective treatments are needed. Immunotherapy based on chimeric antigen receptor (CAR) T cells is a novel technique that redirects T lymphocytes toward specific antigens to eliminate the target cells. It is currently used in haematological cancers but has demonstrated efficacy in mouse models of hypertensive cardiac fibrosis, with activated fibroblasts as the target cells. CAR T cell therapy is associated with significant toxicities, but CAR natural killer cells can overcome efficacy and safety limitations. The use of CAR immunotherapy offers a potential alternative to current therapies for fibrosis reduction and restoration of cardiac function in patients with myocardial fibrosis.

Bone marrow adipocytes fuel emergency hematopoiesis after myocardial infarction.

After myocardial infarction (MI), emergency hematopoiesis produces inflammatory myeloid cells that accelerate atherosclerosis and promote heart failure. Since the balance between glycolysis and mitochondrial metabolism regulates hematopoietic stem cell homeostasis, metabolic cues may influence emergency myelopoiesis. Here, we show in humans and female mice that hematopoietic progenitor cells increase fatty acid metabolism after MI. Blockade of fatty acid oxidation by deleting carnitine palmitoyltransferase (Cpt1A) in hematopoietic cells of Vav1Cre/+Cpt1Afl/fl mice limited hematopoietic progenitor proliferation and myeloid cell expansion after MI. We also observed reduced bone marrow adiposity in humans, pigs and mice following MI. Inhibiting lipolysis in adipocytes using AdipoqCreERT2Atglfl/fl mice or local depletion of bone marrow adipocytes in AdipoqCreERT2iDTR mice also curbed emergency hematopoiesis. Furthermore, systemic and regional sympathectomy prevented bone marrow adipocyte shrinkage after MI. These data establish a critical role for fatty acid metabolism in post-MI emergency hematopoiesis.

Electrophysiological effects of adipose graft transposition procedure (AGTP) on the post-myocardial infarction scar: A multimodal characterization of arrhythmogenic substrate.

Objective: To assess the arrhythmic safety profile of the adipose graft transposition procedure (AGTP) and its electrophysiological effects on post-myocardial infarction (MI) scar. Background: Myocardial repair is a promising treatment for patients with MI. The AGTP is a cardiac reparative therapy that reduces infarct size and improves cardiac function. The impact of AGTP on arrhythmogenesis has not been addressed. Methods: MI was induced in 20 swine. Contrast-enhanced magnetic resonance (ce-MRI), electrophysiological study (EPS), and left-ventricular endocardial high-density mapping were performed 15 days post-MI. Animals were randomized 1:1 to AGTP or sham-surgery group and monitored with ECG-Holter. Repeat EPS, endocardial mapping, and ce-MRI were performed 30 days post-intervention. Myocardial SERCA2, Connexin-43 (Cx43), Ryanodine receptor-2 (RyR2), and cardiac troponin-I (cTnI) gene and protein expression were evaluated. Results: The AGTP group showed a significant reduction of the total infarct scar, border zone and dense scar mass by ce-MRI (p = 0.04), and a decreased total scar and border zone area in bipolar voltage mapping (p < 0.001). AGTP treatment significantly reduced the area of very-slow conduction velocity (<0.2 m/s) (p = 0.002), the number of deceleration zones (p = 0.029), and the area of fractionated electrograms (p = 0.005). No differences were detected in number of induced or spontaneous ventricular arrhythmias at EPS and Holter-monitoring. SERCA2, Cx43, and RyR2 gene expression were decreased in the infarct core of AGTP-treated animals (p = 0.021, p = 0.018, p = 0.051, respectively). Conclusion: AGTP is a safe reparative therapy in terms of arrhythmic risk and provides additional protective effect against adverse electrophysiological remodeling in ischemic heart disease.

Acellular cardiac scaffolds enriched with MSC-derived extracellular vesicles limit ventricular remodelling and exert local and systemic immunomodulation in a myocardial infarction porcine model.

Rationale: Extracellular vesicles (EVs) from mesenchymal stromal cell (MSC) are a potential therapy for cardiac healing after myocardial infarction (MI). Nevertheless, neither their efficient administration nor therapeutic mechanisms are fully elucidated. Here, we evaluate the preclinical efficacy of a tissue engineering approach to locally deliver porcine cardiac adipose tissue MSC-EV (cATMSC-EV) in an acute MI pig model. Methods: After MI by permanent ligation of the coronary artery, pigs (n = 24) were randomized to Untreated or treated groups with a decellularised pericardial scaffold filled with peptide hydrogel and cATMSC-EV purified by size exclusion chromatography (EV-Treated group) or buffer (Control group), placed over the post-infarcted myocardium. Results: After 30 days, cardiac MRI showed an improved cardiac function in EV-Treated animals, with significantly higher right ventricle ejection fraction (+20.8% in EV-Treated; p = 0.026), and less ventricle dilatation, indicating less myocardial remodelling. Scar size was reduced, with less fibrosis in the distal myocardium (-42.6% Col I in EV-Treated vs Untreated; p = 0.03), a 2-fold increase in vascular density (EV-Treated; p = 0.019) and less CCL2 transcription in the infarct core. EV-treated animals had less macrophage infiltration in the infarct core (-31.7% of CD163+ cells/field in EV-Treated; p = 0.026), but 5.8 times more expressing anti-inflammatory CD73 (p = 0.015). Systemically, locally delivered cATMSC-EV also triggered a systemic effect, doubling the circulating IL-1ra (p = 0.01), and reducing the PBMC rush 2d post-MI, the TNFα and GM-CSF levels at 30d post-MI, and modulating the CD73+ and CCR2+ monocyte populations, related to immunomodulation and fibrosis modulation. Conclusions: These results highlight the potential of cATMSC-EV in modulating hallmarks of ischemic injury for cardiac repair after MI.

Circulating virome and inflammatory proteome in patients with ST-elevation myocardial infarction and primary ventricular fibrillation.

Primary ventricular fibrillation (PVF) is a life-threatening complication of ST-segment elevation myocardial infarction (STEMI). It is unclear what roles viral infection and/or systemic inflammation may play as underlying triggers of PVF, as a second hit in the context of acute ischaemia. Here we aimed to evaluate whether the circulating virome and inflammatory proteome were associated with PVF development in patients with STEMI. Blood samples were obtained from non-PVF and PVF STEMI patients at the time of primary PCI, and from non-STEMI healthy controls. The virome profile was analysed using VirCapSeq-VERT (Virome Capture Sequencing Platform for Vertebrate Viruses), a sequencing platform targeting viral taxa of 342,438 representative sequences, spanning all virus sequence records. The inflammatory proteome was explored with the Olink inflammation panel, using the Proximity Extension Assay technology. After analysing all viral taxa known to infect vertebrates, including humans, we found that non-PVF and PVF patients only significantly differed in the frequencies of viruses in the Gamma-herpesvirinae and Anelloviridae families. In particular, most showed a significantly higher relative frequency in non-PVF STEMI controls. Analysis of systemic inflammation revealed no significant differences between the inflammatory profiles of non-PVF and PVF STEMI patients. Inflammatory proteins associated with cell adhesion, chemotaxis, cellular response to cytokine stimulus, and cell activation proteins involved in immune response (IL6, IL8 CXCL-11, CCL-11, MCP3, MCP4, and ENRAGE) were significantly higher in STEMI patients than non-STEMI controls. CDCP1 and IL18-R1 were significantly higher in PVF patients compared to healthy subjects, but not compared to non-PVF patients. The circulating virome and systemic inflammation were not associated with increased risk of PVF development in acute STEMI. Accordingly, novel strategies are needed to elucidate putative triggers of PVF in the setting of acute ischaemia, in order to reduce STEMI-driven sudden death burden.

Mechanisms governing the therapeutic effect of mesenchymal stromal cell-derived extracellular vesicles: A scoping review of preclinical evidence.

Compelling evidence supports the therapeutic benefit of extracellular vesicles (EVs). EVs are nanostructures with a lipid bilayer membrane that are secreted by multiple cells, including mesenchymal stromal cells (MSCs), as means of cellular communication. MSC-EVs, resembling their MSC origin, carry protected immunomodulatory and pro-regenerative cargoes to targeted neighboring or distant cells and tissues. Though treatments focused on MSC-EVs have emerged as greatly versatile approaches to modulate multiple inflammatory-related conditions, crucial concerns, including the possibility of increasing therapeutic outcomes by pre-conditioning parental MSCs or engineering derived EVs and clarification of the most relevant mechanisms of action, remain. Here, we summarize the large amount of preclinical research surrounding the modulation of beneficial effects by MSC-EVs.

Porcine iPSC Generation: Testing Different Protocols to a Successful Application.

Stem cell therapy has an unparalleled potential to treat blood cancers, cardiovascular diseases and neurodegenerative conditions, among others. However, stem cell therapeutics must overcome multiple requirements before reaching clinical trials, including large animal safety and efficacy studies. In cardiovascular diseases swine models are the most widely adopted due to its great translational potential to humans. In this chapter, we will describe several protocols to induce iPSC dedifferentiation in swine fibroblasts, as well as conditioning treatments that may help in the reprogramming process.

Deep Learning Analyses to Delineate the Molecular Remodeling Process after Myocardial Infarction.

Specific proteins and processes have been identified in post-myocardial infarction (MI) pathological remodeling, but a comprehensive understanding of the complete molecular evolution is lacking. We generated microarray data from swine heart biopsies at baseline and 6, 30, and 45 days after infarction to feed machine-learning algorithms. We cross-validated the results using available clinical and experimental information. MI progression was accompanied by the regulation of adipogenesis, fatty acid metabolism, and epithelial-mesenchymal transition. The infarct core region was enriched in processes related to muscle contraction and membrane depolarization. Angiogenesis was among the first morphogenic responses detected as being sustained over time, but other processes suggesting post-ischemic recapitulation of embryogenic processes were also observed. Finally, protein-triggering analysis established the key genes mediating each process at each time point, as well as the complete adverse remodeling response. We modeled the behaviors of these genes, generating a description of the integrative mechanism of action for MI progression. This mechanistic analysis overlapped at different time points; the common pathways between the source proteins and cardiac remodeling involved IGF1R, RAF1, KPCA, JUN, and PTN11 as modulators. Thus, our data delineate a structured and comprehensive picture of the molecular remodeling process, identify new potential biomarkers or therapeutic targets, and establish therapeutic windows during disease progression.

The epicardial delivery of cardiosphere derived cells or their extracellular vesicles is safe but of limited value in experimental infarction.

The epicardial administration of therapeutics via the pericardial sac offers an attractive route, since it is minimally invasive and carries no risks of coronary embolization. The aim of this study was to assess viability, safety and effectiveness of cardiosphere-derived cells (CDCs), their extracellular vesicles (EVs) or placebo administered via a mini-thoracotomy 72 h after experimental infarction in swine. The epicardial administration was completed successfully in all cases in a surgery time (knife-to-skin) below 30 min. No significant differences between groups were found in cardiac function parameters evaluated using magnetic resonance imaging before therapy and at the end of the study, despite a trend towards improved function in CDC-treated animals. Moreover, infarct size at 10 weeks was smaller in treated animals, albeit not significantly. Arrhythmia inducibility did not differ between groups. Pathological examination showed no differences, nor were there any pericardial adhesions evidenced in any case 10 weeks after surgery. These results show that the epicardial delivery of CDCs or their EVs is safe and technically easy 3 days after experimental myocardial infarction in swine, but it does not appear to have any beneficial effect on cardiac function. Our results do not support clinical translation of these therapies as implemented in this work.

Myocardial Infarction by Percutaneous Embolization Coil Deployment in a Swine Model.

Myocardial infarction (MI) is the leading cause of mortality worldwide. Despite the use of evidence-based treatments, including coronary revascularization and cardiovascular drugs, a significant proportion of patients develop pathological left-ventricular remodeling and progressive heart failure following MI. Therefore, new therapeutic options, such as cellular and gene therapies, among others, have been developed to repair and regenerate injured myocardium. In this context, animal models of MI are crucial in exploring the safety and efficacy of these experimental therapies before clinical translation. Large animal models such as swine are preferred over smaller ones due to the high similarity of swine and human hearts in terms of coronary artery anatomy, cardiac kinetics, and the post-MI healing process. Here, we aimed to describe an MI model in pig by permanent coil deployment. Briefly, it comprises a percutaneous selective coronary artery cannulation through retrograde femoral access. Following coronary angiography, the coil is deployed at the target branch under fluoroscopic guidance. Finally, complete occlusion is confirmed by repeated coronary angiography. This approach is feasible, highly reproducible, and emulates the pathogenesis of human non-revascularized MI, avoiding the traditional open-chest surgery and the subsequent postoperative inflammation. Depending on the time of follow-up, the technique is suitable for acute, sub-acute, or chronic MI models.

First-in-human PeriCord cardiac bioimplant: Scalability and GMP manufacturing of an allogeneic engineered tissue graft.

BACKGROUND: Small cardiac tissue engineering constructs show promise for limiting post-infarct sequelae in animal models. This study sought to scale-up a 2-cm2 preclinical construct into a human-size advanced therapy medicinal product (ATMP; PeriCord), and to test it in a first-in-human implantation. METHODS: The PeriCord is a clinical-size (12-16 cm2) decellularised pericardial matrix colonised with human viable Wharton's jelly-derived mesenchymal stromal cells (WJ-MSCs). WJ-MSCs expanded following good manufacturing practices (GMP) met safety and quality standards regarding the number of cumulative population doublings, genomic stability, and sterility. Human decellularised pericardial scaffolds were tested for DNA content, matrix stiffness, pore size, and absence of microbiological growth. FINDINGS: PeriCord implantation was surgically performed on a large non-revascularisable scar in the inferior wall of a 63-year-old male patient. Coronary artery bypass grafting was concomitantly performed in the non-infarcted area. At implantation, the 16-cm2 pericardial scaffold contained 12·5 × 106 viable WJ-MSCs (85·4% cell viability; <0·51 endotoxin units (EU)/mL). Intraoperative PeriCord delivery was expeditious, and secured with surgical glue. The post-operative course showed non-adverse reaction to the PeriCord, without requiring host immunosuppression. The three-month clinical follow-up was uneventful, and three-month cardiac magnetic resonance imaging showed ~9% reduction in scar mass in the treated area. INTERPRETATION: This preliminary report describes the development of a scalable clinical-size allogeneic PeriCord cardiac bioimplant, and its first-in-human implantation. FUNDING: La Marató de TV3 Foundation, Government of Catalonia, Catalan Society of Cardiology, "La Caixa" Banking Foundation, Spanish Ministry of Science, Innovation and Universities, Institute of Health Carlos III, and the European Regional Development Fund.

Silk-Reinforced Collagen Hydrogels with Raised Multiscale Stiffness for Mesenchymal Cells 3D Culture.

Type I collagen hydrogels are of high interest in tissue engineering. With the evolution of 3D bioprinting technologies, a high number of collagen-based scaffolds have been reported for the development of 3D cell cultures. A recent proposal was to mix collagen with silk fibroin derived from Bombyx mori silkworm. Nevertheless, due to the difficulties in the preparation and the characteristics of the protein, several problems such as phase separation and collagen denaturation appear during the procedure. Therefore, the common solution is to diminish the concentration of collagen although in that way the most biologically relevant component is reduced. In this study, we present a new, simple, and effective method to develop a collagen-silk hybrid hydrogel with high collagen concentration and with increased stiffness approaching that of natural tissues, which could be of high interest for the development of cardiac patches for myocardial regeneration and for preconditioning of mesenchymal stem cells (MSCs) to improve their therapeutic potential. Sericin in the silk was preserved by using a physical solubilizing procedure that results in a preserved fibrous structure of type I collagen, as shown by ultrastructural imaging. The macro- and micromechanical properties of the hybrid hydrogels measured by tensile stretch and atomic force microscopy, respectively, showed a more than twofold stiffening than the collagen-only hydrogels. Rheological measurements showed improved printability properties for the developed biomaterial. The suitability of the hydrogels for 3D cell culture was assessed by 3D bioprinting bone marrow-derived MSCs cultured within the scaffolds. The result was a biomaterial with improved printability characteristics that better resembled the mechanical properties of natural soft tissues while preserving biocompatibility owing to the high concentration of collagen. Impact statement In this study, we report the development of silk microfiber-reinforced type I collagen hydrogels for 3D bioprinting and cell culture. In contrast with previously reported studies, a novel physical method allowed the preservation of the silk sericin protein. Hydrogels were stable, showed no phase separation between the biomaterials, and they presented improved printability. An increase between two- and threefold of the multiscale stiffness of the scaffolds was achieved with no need of using additional crosslinkers or complex methods, which could be of high relevance for cardiac patches development and for preconditioning mesenchymal stem cells (MSCs) for therapeutic applications. We demonstrate that bone marrow-derived MSCs can be effectively bioprinted and 3D cultured within the stiffened structures.

Head-to-head comparison of two engineered cardiac grafts for myocardial repair: From scaffold characterization to pre-clinical testing.

Cardiac tissue engineering, which combines cells and supportive scaffolds, is an emerging treatment for restoring cardiac function after myocardial infarction (MI), although, the optimal construct remains a challenge. We developed two engineered cardiac grafts, based on decellularized scaffolds from myocardial and pericardial tissues and repopulated them with adipose tissue mesenchymal stem cells (ATMSCs). The structure, macromechanical and micromechanical scaffold properties were preserved upon the decellularization and recellularization processes, except for recellularized myocardium micromechanics that was ∼2-fold stiffer than native tissue and decellularized scaffolds. Proteome characterization of the two acellular matrices showed enrichment of matrisome proteins and major cardiac extracellular matrix components, considerably higher for the recellularized pericardium. Moreover, the pericardial scaffold demonstrated better cell penetrance and retention, as well as a bigger pore size. Both engineered cardiac grafts were further evaluated in pre-clinical MI swine models. Forty days after graft implantation, swine treated with the engineered cardiac grafts showed significant ventricular function recovery. Irrespective of the scaffold origin or cell recolonization, all scaffolds integrated with the underlying myocardium and showed signs of neovascularization and nerve sprouting. Collectively, engineered cardiac grafts -with pericardial or myocardial scaffolds- were effective in restoring cardiac function post-MI, and pericardial scaffolds showed better structural integrity and recolonization capability.

Myocardial healing using cardiac fat.

INTRODUCTION: Chronic diseases, including myocardial scar healing and heart failure remission, impose huge social and economic burdens, and novel approaches are needed. Several therapeutic modalities are currently being evaluated, including cell therapy, stem cell conditioning, and cardiac tissue engineering. Areas covered: This review discusses the restoration of cardiac function after myocardial infarction using a vascularized flap of autologous cardiac adipose tissue over an akinetic scar. It addresses the risks and benefits of using cardiac adipose progenitors and the adipose graft transposition procedure (AGTP) to ameliorate cardiac dysfunction in preclinical and clinical trials. Expert commentary: The focus is shifting from first-generation studies that used ex vivo expanded and manipulated progenitors to newer second-generation approaches, including AGTP, which are inexpensive and do not raise ethical issues. AGTP safety has been validated, and the ongoing AGTP-2 trial to determine AGTP efficacy and outcome is currently recruiting patients (NCT02798276). This reparative strategy is safe, avoids the risks associated with ex vivo manipulation, and the preclinical and clinical trials performed to date show cardiac function recovery and reduced necrosis. Confirmation of these data in the AGTP-2 trial could pave the way for the clinical use of this novel modality.

Mesenchymal Stem Cells Induce Expression of CD73 in Human Monocytes In Vitro and in a Swine Model of Myocardial Infarction In Vivo.

The ectoenzymes CD39 and CD73 regulate the purinergic signaling through the hydrolysis of adenosine triphosphate (ATP)/ADP to AMP and to adenosine (Ado), respectively. This shifts the pro-inflammatory milieu induced by extracellular ATP to the anti-inflammatory regulation by Ado. Mesenchymal stem cells (MSCs) have potent immunomodulatory capabilities, including monocyte modulation toward an anti-inflammatory phenotype aiding tissue repair. In vitro, we observed that human cardiac adipose tissue-derived MSCs (cATMSCs) and umbilical cord MSCs similarly polarize monocytes toward a regulatory M2 phenotype, which maintained the expression of CD39 and induced expression of CD73 in a cell contact dependent fashion, correlating with increased functional activity. In addition, the local treatment with porcine cATMSCs using an engineered bioactive graft promoted the in vivo CD73 expression on host monocytes in a swine model of myocardial infarction. Our results suggest the upregulation of ectonucleotidases on MSC-conditioned monocytes as an effective mechanism to amplify the long-lasting immunomodulatory and healing effects of MSCs delivery.

Mesenchymal stem cells for cardiac repair: are the actors ready for the clinical scenario?

For years, sufficient progress has been made in treating heart failure following myocardial infarction; however, the social and economic burdens and the costs to world health systems remain high. Moreover, treatment advances have not resolved the underlying problem of functional heart tissue loss. In this field of research, for years we have actively explored innovative biotherapies for cardiac repair. Here, we present a general, critical overview of our experience in using mesenchymal stem cells, derived from cardiac adipose tissue and umbilical cord blood, in a variety of cell therapy and tissue engineering approaches. We also include the latest advances and future challenges, including good manufacturing practice and regulatory issues. Finally, we evaluate whether recent approaches hold potential for reliable translation to clinical trials.

Rationale and design of a multicentre, prospective, randomised, controlled clinical trial to evaluate the efficacy of the adipose graft transposition procedure in patients with a myocardial scar: the AGTP II trial.

INTRODUCTION: Cardiac adipose tissue is a source of progenitor cells with regenerative capacity. Studies in rodents demonstrated that the intramyocardial delivery of cells derived from this tissue improves cardiac function after myocardial infarction (MI). We developed a new reparative approach for damaged myocardium that integrates the regenerative properties of cardiac adipose tissue with tissue engineering. In the adipose graft transposition procedure (AGTP), we dissect a vascularised flap of autologous pericardial adipose tissue and position it over the myocardial scarred area. Following encouraging results in acute and chronic MI porcine models, we performed the clinical trial (NCT01473433, AdiFLAP trial) to evaluate safety in patients with chronic MI undergoing coronary artery bypass graft. The good safety profile and trends in efficacy warranted a larger trial. STUDY DESIGN: The AGTP II trial (NCT02798276) is an investigator initiated, prospective, randomised, controlled, multicentre study to assess the efficacy of the AGTP in 108 patients with non-revascularisable MI. Patients will be assigned to standard clinical practice or the AGTP. The primary endpoint is change in necrotic mass ratio by gadolinium enhancement at 91 and 365 days. Secondary endpoints include improvement in regional contractibility by MRI at 91 and 365 days; changes in functional MRI parameters (left ventricular ejection fraction, left and right ventricular geometric remodelling) at 91 and 365 days; levels of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) at 7, 91 and 365 days; appearance of arrhythmias from 24 hour Holter monitoring at 24 hours, and at 91 and 365 days; all cause death or re-hospitalisation at 365 days; and cardiovascular death or re-hospitalisation at 365 days. ETHICS AND DISSEMINATION: The institutional review board approved the trial which will comply with the Declaration of Helsinki. All patients will provide informed consent. It may offer a novel, effective and technically simple technique for patients with no other therapeutic options. The results will be submitted to indexed medical journals and national and international meetings. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT02798276, pre-results.

Preclinical Safety Evaluation of Allogeneic Induced Pluripotent Stem Cell-Based Therapy in a Swine Model of Myocardial Infarction.

The combination of biomatrices and induced pluripotent stem cell (iPSC) derivatives to aid repair and myocardial scar formation may soon become a reality for cardiac regenerative medicine. However, the tumor risk associated with residual undifferentiated cells remains an important safety concern of iPSC-based therapies. This concern is not satisfactorily addressed in xenotransplantation, which requires immune suppression of the transplanted animal. In this study, we assessed the safety of transplanting undifferentiated iPSCs in an allogeneic setting. Given that swine are commonly used as large animal models in cardiac medicine, we used porcine iPSCs (p-iPSCs) in conjunction with bioengineered constructs that support recovery after acute myocardial infarction. Histopathology analyses found no evidence of p-iPSCs or p-iPSC-derived cells within the host myocardium or biomatrices after 30 and 90 days of follow-up. Consistent with the disappearance of the implanted cells, we could not observe functional benefit of these treatments in terms of left ventricular ejection fraction, cardiac output, ventricular volumes, or necrosis. We therefore conclude that residual undifferentiated iPSCs should pose no safety concern when used on immune-competent recipients in an allogeneic setting, at least in the context of cardiac regenerative medicine.

Intracoronary Administration of Allogeneic Adipose Tissue-Derived Mesenchymal Stem Cells Improves Myocardial Perfusion But Not Left Ventricle Function, in a Translational Model of Acute Myocardial Infarction.

BACKGROUND: Autologous adipose tissue-derived mesenchymal stem cells (ATMSCs) therapy is a promising strategy to improve post-myocardial infarction outcomes. In a porcine model of acute myocardial infarction, we studied the long-term effects and the mechanisms involved in allogeneic ATMSCs administration on myocardial performance. METHODS AND RESULTS: Thirty-eight pigs underwent 50 minutes of coronary occlusion; the study was completed in 33 pigs. After reperfusion, allogeneic ATMSCs or culture medium (vehicle) were intracoronarily administered. Follow-ups were performed at short (2 days after acute myocardial infarction vehicle-treated, n=10; ATMSCs-treated, n=9) or long term (60 days after acute myocardial infarction vehicle-treated, n=7; ATMSCs-treated, n=7). At short term, infarcted myocardium analysis showed reduced apoptosis in the ATMSCs-treated animals (48.6±6% versus 55.9±5.7% in vehicle; P=0.017); enhancement of the reparative process with up-regulated vascular endothelial growth factor, granulocyte macrophage colony-stimulating factor, and stromal-derived factor-1α gene expression; and increased M2 macrophages (67.2±10% versus 54.7±10.2% in vehicle; P=0.016). In long-term groups, increase in myocardial perfusion at the anterior infarct border was observed both on day-7 and day-60 cardiac magnetic resonance studies in ATMSCs-treated animals, compared to vehicle (87.9±28.7 versus 57.4±17.7 mL/min per gram at 7 days; P=0.034 and 99±22.6 versus 43.3±14.7 22.6 mL/min per gram at 60 days; P=0.0001, respectively). At day 60, higher vascular density was detected at the border zone in the ATMSCs-treated animals (118±18 versus 92.4±24.3 vessels/mm2 in vehicle; P=0.045). Cardiac magnetic resonance-measured left ventricular ejection fraction of left ventricular volumes was not different between groups at any time point. CONCLUSIONS: In this porcine acute myocardial infarction model, allogeneic ATMSCs-based therapy was associated with increased cardioprotective and reparative mechanisms and with better cardiac magnetic resonance-measured perfusion. No effect on left ventricular volumes or ejection fraction was observed.