Immediate Intramyocardial Bone Marrow-Derived Mononuclear Cells Implantation in Minipig Myocardium After Permanent Coronary Artery Ligation: Magnetic Resonance Imaging With Histopathologic and Immunochemical Correlation

Stem Cell Therapy against Ischemic Heart Disease

Ischemic heart disease, which is one of the top killers worldwide, encompasses a series of heart problems stemming from a compromised coronary blood supply to the myocardium. The severity of the disease ranges from an unstable manifestation of ischemic symptoms, such as unstable angina, to myocardial death, that is, the immediate life-threatening condition of myocardial infarction. Even though patients may survive myocardial infarction, the resulting ischemia-reperfusion injury triggers a cascade of inflammatory reactions and oxidative stress that poses a significant threat to myocardial function following successful revascularization. Moreover, despite evidence suggesting the presence of cardiac stem cells, the fact that cardiomyocytes are terminally differentiated and cannot significantly regenerate after injury accounts for the subsequent progression to ischemic cardiomyopathy and ischemic heart failure, despite the current advancements in cardiac medicine. In the last two decades, researchers have realized the possibility of utilizing stem cell plasticity for therapeutic purposes. Indeed, stem cells of different origin, such as bone-marrow- and adipose-derived mesenchymal stem cells, circulation-derived progenitor cells, and induced pluripotent stem cells, have all been shown to play therapeutic roles in ischemic heart disease. In addition, the discovery of stem-cell-associated paracrine effects has triggered intense investigations into the actions of exosomes. Notwithstanding the seemingly promising outcomes from both experimental and clinical studies regarding the therapeutic use of stem cells against ischemic heart disease, positive results from fraud or false data interpretation need to be taken into consideration. The current review is aimed at overviewing the therapeutic application of stem cells in different categories of ischemic heart disease, including relevant experimental and clinical outcomes, as well as the proposed mechanisms underpinning such observations.

Safety and efficacy of intracoronary artery administration of human bone marrow-derived mesenchymal stem cells in STEMI of Lee-Sung pigs—A preclinical study for supporting the feasibility of the OmniMSC-AMI phase I clinical trial

Background

This study tested whether early left intracoronary arterial (LAD) administration of human bone marrow-derived mesenchymal stem cells (hBMMSCs, called OmniMSCs) in acute ST-segment elevation myocardial infarction (STEMI) of Lee-Sung pigs induced by 90 min balloon-occluded LAD was safe and effective.

Methods and results

Young male Lee-Sung pigs were categorized into SC (sham-operated control, n = 3), AMI-B (STEMI + buffer/21 cc/administered at 90 min after STEMI, n = 6), and AMI-M [acute myocardial infarction (AMI) + hBMMSCs/1.5 × 107/administered at 90 min after STEMI, n = 6] groups. By 2 and 5 months after STEMI, the cardiac magnetic resonance imaging demonstrated that the muscle scar score (MSS) and abnormal cardiac muscle exercise score in the infarct region were significantly increased in the AMI-B than in the SC group that were significantly reversed in the AMI-M group, whereas the left ventricular ejection function by each month (from 1 to 5) displayed an opposite pattern of MSS among the groups (all p < 0.001). By 5 months, histopathological findings of infarct and fibrosis areas and isolectin-B4 exhibited an identical pattern, whereas the cellular expressions of troponin-I/troponin-T/von Willebrand factor exhibited an opposite pattern of MSS among the groups (all p < 0.001). The ST-segment resolution (>80%) was significantly earlier (estimated after 6-h AMI) in the AMI-M group than in the AMI-B group (p < 0.001). The protein expressions of inflammation (IL-1β/TNF-α/NF-κB)/oxidative stress (NOX-1/NOX-2/oxidized protein)/apoptosis (cleaved caspase-3/cleaved PARP)/DNA damage (γ-H2AX) displayed an identical pattern to MSS among the groups, whereas the protein expressions of angiogenesis factors (SDF-1α/VEGF) were significantly and progressively increased from SC, AMI-B, to AMI-M groups (all p < 0.001).

Conclusion

Early intra-LAD transfusion of OmniMSC treatment effectively reduced the infarct size and preserved LV function in porcine STEMI.

Efficacy of Stem Cell Therapy in Large Animal Models of Ischemic Cardiomyopathies: A Systematic Review and Meta-Analysis

Stem-cell therapy provides a promising strategy for patients with ischemic heart disease. In recent years, numerous studies related to this therapeutic approach were performed; however, the results were often heterogeneous and contradictory. For this reason, we conducted a systematic review and meta-analysis of trials, reporting the use of stem-cell treatment against acute or chronic ischemic cardiomyopathies in large animal models with regard to Left Ventricular Ejection Fraction (LVEF). The defined research strategy was applied to the PubMed database to identify relevant studies published from January 2011 to July 2021. A random-effect meta-analysis was performed on LVEF mean data at follow-up between control and stem-cell-treated animals. In order to improve the definition of the effect measure and to analyze the factors that could influence the outcomes, a subgroup comparison was conducted. Sixty-six studies (n = 1183 animals) satisfied our inclusion criteria. Ischemia/reperfusion infarction was performed in 37 studies, and chronic occlusion in 29 studies; moreover, 58 studies were on a pig animal model. The meta-analysis showed that cell therapy increased LVEF by 7.41% (95% Confidence Interval 6.23−8.59%; p < 0.001) at follow-up, with significative heterogeneity and high inconsistency (I2 = 82%, p < 0.001). By subgroup comparison, the follow-up after 31−60 days (p = 0.025), the late cell injection (>7 days, p = 0.005) and the route of cellular delivery by surgical treatment (p < 0.001) were significant predictors of LVEF improvement. This meta-analysis showed that stem-cell therapy may improve heart function in large animal models and that the swine specie is confirmed as a relevant animal model in the cardiovascular field. Due to the significative heterogeneity and high inconsistency, future translational studies should be designed to take into account the evidenced predictors to allow for the reduction of the number of animals used.

Complementary Embryonic and Adult Cell Populations Enhance Myocardial Repair in Rat Myocardial Injury Model

We compared the functional outcome of Isl-1+ cardiac progenitors, CD90+ bone marrow-derived progenitor cells, and the combination of the two in a rat myocardial infarction (MI) model. Isl-1+ cells were isolated from embryonic day 12.5 (E12.5) rat hearts and expanded in vitro. Thy-1+/CD90+ cells were isolated from the bone marrow of adult Sprague-Dawley rats by immunomagnetic cell sorting. Six-week-old female Sprague-Dawley rats underwent permanent left anterior descending (LAD) coronary artery ligation and received intramyocardial injection of either saline, Isl-1+ cells, CD90+ cells, or a combination of Isl-1+ and CD90+ cells, at the time of infarction. Cells were delivered transepicardially to the peri-infarct zone. Left ventricular function was assessed by transthoracic echocardiography at 1- and 4-week post-MI and by Millar catheterization (-dP/dt and +dP/dt) at 4-week post-MI. Fluorescence in situ hybridization (Isl-1+cells) and monochrystalline iron oxide nanoparticles labeling (MION; CD90+ cells) were performed to assess biodistribution of transplanted cells. Only the combination of cells demonstrated a significant improvement of cardiac function as assessed by anterior wall contractility, dP/dt (max), and dP/dt (min), compared to Isl-1+ or CD90+ cell monotherapies. In the combination cell group, viable cells were detected at week 4 when anterior wall motion was completely restored. In conclusion, the combination of Isl-1+ cardiac progenitors and adult bone marrow-derived CD90+ cells shows prolonged and robust myocardial tissue repair and provides support for the use of complementary cell populations to enhance myocardial repair.

Therapeutic potential of tacrolimus on acute myocardial infarction in minipigs: analysis with serial cardiac magnetic resonance and changes at histological and protein levels

This study investigates the therapeutic potential of intracoronary tacrolimus against acute myocardial infarction (AMI) in minipigs with serial cardiac magnetic resonance (CMR) and changes at histological and protein levels. Twelve minipigs subjected to permanent left anterior descending artery ligation were randomized as tac-treated group (n = 6, with intracoronary tacrolimus treatment) and controls (n = 6). CMR with cine and late gadolinium enhancement (LGE) studies were performed on postoperative days 2, 5, and 21. There were no significant differences in left ventricular function (LVF), contractility, and LGE between the two groups on day 2. On day 5, the tac-treated group showed a significantly higher ejection fraction, smaller infarct, and lower day-5/day-2 infarct ratio than controls. On day 21, the controls demonstrated further deterioration of LVF and infarct. Contrastingly, the tac-treated animals demonstrated preservation of LVF, contractility, significantly smaller infarct, and lower day-21/day-2 infarct ratios compared with those on day 5 and controls. The in vivo CMR results were correlated with in vitro findings on histology, immunostaining, and Western blotting which revealed significantly less fibrosis, higher vascularities, less CD68+ and CD40+ inflammatory cells, lower expressions of inflammatory (MMP-9, NF-κB, and TNF-α), and apoptotic (Bax, Caspase-3, c-PARP) biomarkers, respectively, in tac-treated AMI minipigs than controls.

Prompt bone marrow-derived mesenchymal stem cell therapy enables early porcine heart function recovery from acute myocardial infarction

Impact of early bone marrow-derived mesenchymal stem cell (BMDMSC) implantation on left ventricular (LV) function after AMI was studied.Twelve mini-pigs were equally divided into placebo (AMI through left coronary artery ligation) and cell-treated groups [BMDMSCs (3.0 × 10(7)) implanted into infarct area (IA)] with myocardium harvested by post-AMI day 90. Six healthy animals served as controls.On post-AMI day 90, magnetic resonance imaging showed a lower LV ejection fraction but higher LV dimensions in the placebo group (P < 0.003) that also had increased IAs but reduced wall thickness (P < 0.005). Pro-apoptotic gene expressions (Bax, caspase-3) and apoptotic nucleus number in IAs and peri-IAs were highest in the placebo group (P < 0.001). Inflammatory biomarker expressions (MMP-9, oxidized protein, CD40+ cells) were highest, whereas those of angiogenesis (VEGF, CD31+ cells, SDF-1α, CXCR4) and myocardium-preservation (connexin43, troponin-I, cytochrome-C) were lowest in the placebo group (P < 0.01).BMDMSC implantation preserved LV function and alleviated remodeling at post-AMI day 90.

Innate immune response after acute myocardial infarction and pharmacomodulatory action of tacrolimus in reducing infarct size and preserving myocardial integrity

Background

This study investigated the association between innate immune reaction and myocardial damage after acute myocardial infarction (AMI) and anti-inflammatory role of tacrolimus in reducing infarct size. Male mini-pigs (n=18) were equally categorized into sham control (SC), untreated AMI (by ligation of left anterior descending coronary artery), and AMI-Tacrolimus (AMI-Tac) (0.5 mg intra-coronary injection 30 minutes post-AMI). Cardiac magnetic resonance imaging (MRI) was performed at post-AMI days 2, 5 and 21 before sacrificing the animals.

Results

By post-AMI day 21, left ventricular ejection fraction (LVEF) was lowest in untreated AMI animals, significantly higher in SC than in AMI-Tac group (all p<0.003). Infarct areas at basal, middle, and apical levels, numbers of CD14+ and iNOS+ cells in infarct area (IA) and peri-IA, and protein expression of CD14, CD68, and Ly6g from circulating inflammatory cells showed an opposite pattern compared with that of LVEF in all groups (all p<0.005). Protein expressions of MCP-1, MIP-1, TNF-α, NF-κB, iNOS, and IL-12 in IA and peri-IA exhibited an identical pattern compared to that of CD14, CD68, and Ly6g from circulating inflammatory cells (all p<0.01). Expressions of myocardial damage biomarkers in IA and peri-IA [γ-H2AX, β-myosin heavy chain (MHC), Smad3, TGF-β] were highest in AMI and higher in AMI-Tac than in SC, whereas expressions of myocardial integrity biomarkers (connexin43, mitochondrial cytochrome-C, α-MHC, BMP-2, Smad1/5) were opposite to those of damage biomarkers (all p<0.001).

Conclusion

Innate immune responses were markedly augmented and LVEF was significantly reduced after AMI but were remarkably improved after tacrolimus treatment.

Mesenchymal stromal cells from unconventional model organisms

Mesenchymal stromal cells (MSCs) are multipotent, plastic, adherent cells able to differentiate into osteoblasts, chondroblasts and adipocytes. MSCs can be isolated from many different body compartments of adult and fetal individuals. The most commonly studied MSCs are isolated from humans, mice and rats. However, studies are also being conducted with the use of MSCs that originate from different model organisms, such as cats, dogs, guinea pigs, ducks, chickens, buffalo, cattle, sheep, goats, horses, rabbits and pigs. MSCs derived from unconventional model organisms all present classic fibroblast-like morphology, the expression of MSC-associated cell surface markers such as CD44, CD73, CD90 and CD105 and the absence of CD34 and CD45. Moreover, these MSCs have the ability to differentiate into osteoblasts, chondroblasts and adipocytes. The MSCs isolated from unconventional model organisms are being studied for their potential to heal different tissue defects and injuries and for the development of scaffold compositions that improve the proliferation and differentiation of MSCs for tissue engineering.

A historical overview of magnetic resonance imaging, focusing on technological innovations

Magnetic resonance imaging (MRI) has now been used clinically for more than 30 years. Today, MRI serves as the primary diagnostic modality for many clinical problems. In this article, historical developments in the field of MRI will be discussed with a focus on technological innovations. Topics include the initial discoveries in nuclear magnetic resonance that allowed for the advent of MRI as well as the development of whole-body, high field strength, and open MRI systems. Dedicated imaging coils, basic pulse sequences, contrast-enhanced, and functional imaging techniques will also be discussed in a historical context. This article describes important technological innovations in the field of MRI, together with their clinical applicability today, providing critical insights into future developments.

Rejuvenation of Aged Pig Facial Skin by Transplanting Allogeneic Granulocyte Colony-Stimulating Factor-Induced Peripheral Blood Stem Cells from a Young Pig

Following a stroke, the administration of stem cells that have been treated with granulocyte colony-stimulating factor (GCSF) can ameliorate functional deficits in both rats and humans. It is not known, however, whether the application of GCSF-mobilized peripheral blood stem cells (PBSCs) to human skin can function as an antiaging treatment. We used a Lanyu pig ( Sus scrofa) model, since compared with rodents, the structure of a pig's skin is very similar to human skin, to provide preliminary data on whether these cells can exert antiaging effects over a short time frame. GCSF-mobilized PBSCs from a young male Lanyu pig (5 months) were injected intradermally into the cheek skin of aged female Lanyu pigs, and tissues before and after the cell injections were compared to determine whether this treatment caused skin rejuvenation. Increased levels of collagen, elastin, hyaluronic acid, and the hyaluronic acid receptor CD44 were observed in both dermal and subcutaneous layers following the injection of PBSCs. In addition, the treated skin tissue was tighter and more elastic than adjacent control regions of aged skin tissue. In the epidermal layer, PBSC injection altered the levels of both involucrin and integrin, indicating an increased rate of epidermal cell renewal as evidenced by reductions in both cornified cells and cells of the spinous layers and increases in the number of dividing cells within the basal layer. We found that the exogenous PBSCs, visualized using fluorescence in situ hybridization, were located primarily in hair follicles and adjacent tissues. In summary, PBSC injection restored young skin properties in the skin of aged (90 months) pigs. On the basis of our preliminary data, we conclude that intra dermal injection of GCSF-mobilized PBSCs from a young pig can rejuvenate the skin in aged pigs.