Cardiac Repair and Regeneration: The Value of Cell Therapies

Analyzing VEGFA/VEGFR1 Interaction: Application of the Resonant Recognition Model-Stockwell Transform Method to Explore Potential Therapeutics for Angiogenesis-Related Diseases

The interaction between vascular endothelial growth factor A (VEGFA) and VEGF receptor 1(VEGFR1) is a central focus for drug development in pathological angiogenesis, where aberrant angiogenesis underlies various anomalies necessitating therapeutic intervention. Identifying hotspots of these proteins is crucial for developing new therapeutics. Although machine learning techniques have succeeded significantly in prediction tasks, they struggle to pinpoint hotspots linked to angiogenic activity accurately. This study involves the collection of diverse VEGFA and VEGFR1 protein sequences from various species via the UniProt database. Electron-ion interaction Potential (EIIP) values were assigned to individual amino acids and transformed into frequency-domain representations using discrete Fast Fourier Transform (FFT). A consensus spectrum emerged by consolidating FFT data from multiple sequences, unveiling specific characteristic frequencies. Subsequently, the Stockwell Transform (ST) was employed to yield the hotspots. The Resonant Recognition Model (RRM) identified a characteristic frequency of 0.128007 with an associated wavelength of 1570 nm and RRM-ST identified hotspots for VEGFA (Human 36, 46, 48, 67, 71, 74, 82, 86, 89, 93) and VEGFR1 (Human 224, 259, 263, 290, 807, 841, 877, 881, 885, 892, 894, 909, 913, 1018, 1022, 1026, 1043). These findings were cross-validated by Hotspots Wizard 3.0 webserver and Protein Data Bank (PDB). The study proposes using a 1570 nm wavelength for photo bio modulation to boost VEGFA/VEGFR1 interaction in the condition that is needed. It also aims to reduce VEGFA/VEGFR2 interaction, limiting harmful angiogenesis in conditions like diabetic retinopathy. Also, the identified hotspots assist in designing agonistic or antagonistic peptides tailored to specific medical requirements with abnormal angiogenesis.

Cardiac Remodeling and Repair: Recent Approaches, Advancements, and Future Perspective

The limited ability of mammalian adult cardiomyocytes to proliferate following an injury to the heart, such as myocardial infarction, is a major factor that results in adverse fibrotic and myocardial remodeling that ultimately leads to heart failure. The continued high degree of heart failure-associated morbidity and lethality requires the special attention of researchers worldwide to develop efficient therapeutics for cardiac repair. Recently, various strategies and approaches have been developed and tested to extrinsically induce regeneration and restoration of the myocardium after cardiac injury have yielded encouraging results. Nevertheless, these interventions still lack adequate success to be used for clinical interventions. This review highlights and discusses both cell-based and cell-free therapeutic approaches as well as current advancements, major limitations, and future perspectives towards developing an efficient therapeutic method for cardiac repair.

Application of Cell, Tissue, and Biomaterial Delivery in Cardiac Regenerative Therapy

Cardiovascular diseases (CVD) are the leading cause of death around the world, being responsible for 31.8% of all deaths in 2017 (Roth, G. A. et al. The Lancet 2018, 392, 1736-1788). The leading cause of CVD is ischemic heart disease (IHD), which caused 8.1 million deaths in 2013 (Benjamin, E. J. et al. Circulation 2017, 135, e146-e603). IHD occurs when coronary arteries in the heart are narrowed or blocked, preventing the flow of oxygen and blood into the cardiac muscle, which could provoke acute myocardial infarction (AMI) and ultimately lead to heart failure and death. Cardiac regenerative therapy aims to repair and refunctionalize damaged heart tissue through the application of (1) intramyocardial cell delivery, (2) epicardial cardiac patch, and (3) acellular biomaterials. In this review, we aim to examine these current approaches and challenges in the cardiac regenerative therapy field.

Targeted delivery of extracellular vesicles in heart injury

Extracellular vesicles (EVs) are nanoscale extracellular vesicles derived from endocytosis that are crucial to intercellular communication. EVs possess natural biocompatibility and stability that allow them to cross biological membranes and that protect them from degradation. Recent studies have shown that EVs-mediated crosstalk between different cell types in the heart could play important roles in the maintenance of cardiac homeostasis and the pathogenesis of heart diseases. In particular, EVs secreted by different types of stem cells exhibit cardioprotective effects. However, numerous studies have shown that intravenously injected EVs are quickly cleared by macrophages of the mononuclear phagocyte system (MPS) and preferentially accumulate in MPS organs such as the liver, spleen, and lung. In this review, we discuss exosome biogenesis, the role of EVs in heart diseases, and challenges in delivering EVs to the heart. Furthermore, we extensively discuss the targeted delivery of EVs for treating ischemic heart disease. These understandings will aid in the development of effective treatment strategies for heart diseases.

Adult sox10+ Cardiomyocytes Contribute to Myocardial Regeneration in the Zebrafish

During heart regeneration in the zebrafish, fibrotic tissue is replaced by newly formed cardiomyocytes derived from preexisting ones. It is unclear whether the heart is composed of several cardiomyocyte populations bearing different capacity to replace lost myocardium. Here, using sox10 genetic fate mapping, we identify a subset of preexistent cardiomyocytes in the adult zebrafish heart with a distinct gene expression profile that expanded after cryoinjury. Genetic ablation of sox10⁺ cardiomyocytes impairs cardiac regeneration, revealing that these cells play a role in heart regeneration.

Effect of a dianthin G analogue in the differentiation of rat bone marrow mesenchymal stem cells into cardiomyocytes

Loss of cardiomyocytes due to myocardial infarction results in ventricular remodeling which includes non-contractile scar formation, which can lead to heart failure. Stem cell therapy aims to replace the scar tissue with the functional myocardium. Mesenchymal stem cells (MSCs) are undifferentiated cells capable of self-renewal as well as differentiation into multiple lineages. MSCs can be differentiated into cardiomyocytes by treating them with small molecules and peptides. Here, we report for the first time, the role of a cyclic peptide, an analogue of dianthin G, [Glu²]-dianthin G (1) in the in vitro cardiac differentiation of rat bone marrow MSCs. In this study, [Glu²]-dianthin G (1) was synthesized using solid-phase total synthesis and characterized by NMR spectroscopy. MSCs were treated with two different concentrations (0.025 and 0.05 mM) of the peptide separately for 72 h and then incubated for 15 days to allow the cells to differentiate into cardiomyocytes. Treated cells were analyzed for the expression of cardiac-specific genes and proteins. Results showed significant upregulation of cardiac-specific genes GATA4, cardiac troponin T (cTnT), cardiac troponin I (cTnI), cardiac myosin heavy chain, and connexin 43 in the treated MSCs compared to the untreated control. For cardiac-specific proteins, GATA4, cTnT, and Nkx2.5 were analyzed in the treated cells and were shown to have significant upregulation as compared to the untreated control. In conclusion, this study has demonstrated the cardiac differentiation potential of [Glu²]-dianthin G (1)-treated rat bone marrow MSCs in vitro both at the gene and at the protein levels. Transplantation of pre-differentiated MSCs into the infarcted myocardium may result in the efficient regeneration of cardiac cells and restoration of normal cardiac function.

How to Stimulate Myocardial Regeneration in Adult Mammalian Heart: Existing Views and New Approaches

Stem cell-based therapy has been considered as a promising option in the treatment of ischemic heart disease. Although stem cell administration resulted in the temporary improvement of myocardial contractility in the majority of studies, the formation of new cardiomyocytes within the injured myocardium has not been conclusively demonstrated. Consequently, the focus of research in the field has since shifted to stem cell-derived paracrine factors, including cytokines, growth factors, mRNA, and miRNA. Notably, both mRNA and miRNA can enter into the extracellular space either in soluble form or packed into membrane vesicles. Stem cell-derived paracrine factors have been shown to suppress inflammation and apoptosis, stimulate angiogenesis, and amplify the proliferation and differentiation of resident cardiac stem cells (CSCs). Such features have led to exosomes being considered as potential drug candidates affording myocardial regeneration. The search for chemical signals capable of stimulating cardiomyogenesis is ongoing despite continuous debates regarding the ability of mature cardiomyocytes to divide or dedifferentiate, transdifferentiation of other cells into cardiomyocytes, and the ability of CSCs to differentiate into cardiomyocytes. Future research is aimed at identifying novel cell candidates capable of differentiating into cardiomyocytes. The observation that CSCs can undergo intracellular development with the formation of “cell-in-cell structure” and subsequent release of transitory amplifying cells with the capacity to differentiate into cardiomyocytes may provide clues for stimulating regenerative cardiomyogenesis.

Huoxue Wentong Formula ameliorates myocardial infarction in rats through inhibiting CaMKII oxidation and phosphorylation

Background

The Chinese medicine Huoxue Wentong Formula (HXWTF) was used to treat thoracic obstruction and angina pectoris in clinic, which has not been investigated in myocardial ischemia-induced apoptosis and angiogenic function. Here we aimed to investigate the roles of HXWTF in rats with myocardial ischemia-induced apoptosis and angiogenesis disorders, as well as to reveal the potential mechanisms.

Methods

Male SD rats were subjected to coronary artery ligation followed by HXWTF (420, 840 and 1680 mg/kg/day, p.o.) or isosorbide mononitrate (6.3 mg/kg/day, p.o.) treatment for 4 weeks. Electrocardiogram (ECG) and Echocardiography (ECHO) were used to measure cardiac function. Hematoxylin and eosin (H&E) staining and CD34/α-SMA immunohistochemical staining were performed to observe the ischemic heart sections pathological changes and angiogenesis. Then, the effects on cardiomyocyte apoptosis of H9c2 and tube formation of HCMECs were observed, as well as the changes in the levels of total calmodulin dependent protein kinase II (t-CaMKII), phosphorylated CaMKII (p-CaMKII), oxidized CaMKII (ox-CaMKII), CD34, and Bcl-2/Bax ratio were detected.

Results

Rats with coronary artery ligation exhibited abnormal cardiac function, enlarged myocardial space, disorderly arranged myocardial fibers, inflammatory cells infiltrated, and aggravated myocardial cell apoptosis, along with angiogenesis dysfunction. The expressions of CD34, p-CaMKII, and ox-CaMKII were elevated and Bcl-2/Bax ratio was diminished in ischemic hearts and H/SD-treated H9c2 or HCMECs, while HXWTF treatment completely rescued angiogenic dysfunction, inhibited cardiomyocyte apoptosis, and down-regulated cardiac CaMKII oxidation and phosphorylation activities.

Conclusion

Our study demonstrates that HXWTF improves myocardial infarction possibly through inhibiting CaMKII oxidation and phosphorylation levels, facilitating angiogenic function and alleviating cardiomyocyte apoptosis. Thus, therapeutics targeting CaMKII activities may be a promising strategy for rescuing ischemic cardiomyopathy.

Tendon and Ligament Healing and Current Approaches to Tendon and Ligament Regeneration

Ligament and tendon injuries are common problems in orthopedics. There is a need for treatments that can expedite nonoperative healing or improve the efficacy of surgical repair or reconstruction of ligaments and tendons. Successful biologically-based attempts at repair and reconstruction would require a thorough understanding of normal tendon and ligament healing. The inflammatory, proliferative, and remodeling phases, and the cells involved in tendon and ligament healing will be reviewed. Then, current research efforts focusing on biologically-based treatments of ligament and tendon injuries will be summarized, with a focus on stem cells endogenous to tendons and ligaments. Statement of clinical significance: This paper details mechanisms of ligament and tendon healing, as well as attempts to apply stem cells to ligament and tendon healing. Understanding of these topics could lead to more efficacious therapies to treat ligament and tendon injuries. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:7-12, 2020.

Designer artificial membrane binding proteins to direct stem cells to the myocardium

We present a new cell membrane modification methodology where the inherent heart tissue homing properties of the infectious bacteria Streptococcus gordonii are transferred to human stem cells. This is achieved via the rational design of a chimeric protein-polymer surfactant cell membrane binding construct, comprising the cardiac fibronectin (Fn) binding domain of the bacterial adhesin protein CshA fused to a supercharged protein. Significantly, the protein-polymer surfactant hybrid spontaneously inserts into the plasma membrane of stem cells without cytotoxicity, instilling the cells with a high affinity for immobilized fibronectin. Moreover, we show that this cell membrane reengineering approach significantly improves retention and homing of stem cells delivered either intracardially or intravenously to the myocardium in a mouse model.

Cardioprotective effects of omega-3 fatty acids and ascorbic acid improve regenerative capacity of embryonic stem cell-derived cardiac lineage cells

One of the major issues in cell therapy of myocardial infarction (MI) is early death of engrafted cells in a harsh oxidative stress environment, which limits the potential therapeutic utility of this strategy in the clinical setting. Increasing evidence implicates beneficial effects of omega-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and ascorbic acid (AA) in cardiovascular diseases, in particular their role in ameliorating fibrosis. In the current study, we aim to assess the cytoprotective role of EPA + DHA and AA in protecting embryonic stem cell (ESC)-derived cardiac lineage cells and amelioration of fibrosis. Herein, we have shown that preincubation of the cells with EPA + DHA + AA prior to H₂ O₂ treatment attenuated generation of reactive oxygen species (ROS) and enhanced cell viability. Gene expression analysis revealed that preincubation with EPA + DHA + AA followed by H₂ O₂ treatment, upregulated heme oxygenase-1 (HO-1) along with cardiac markers (GATA4, myosin heavy chain, α isoform [MYH6]), connexin 43 [CX43]) and attenuated oxidative stress-induced upregulation of fibroblast markers (vimentin and collagen type 1 [Col1]). Alterations in gene expression patterns were followed by marked elevation of cardiac troponin (TNNT2) positive cells and reduced numbers of vimentin positive cells. An injection of EPA + DHA + AA-pretreated ESC-derived cardiac lineage cells into the ischemic myocardium of a rat model of MI significantly reduced fibrosis compared to the vehicle group. This study provided evidence that EPA + DHA + AA may be an appropriate preincubation regimen for regenerative purposes. © 2019 BioFactors, 45(3):427-438, 2019.

Rationale and design of a prospective, randomised study of retrograde application of bone marrow aspirate concentrate (BMAC) through coronary sinus in patients with congestive heart failure of ischemic etiology (the RETRO study)

Background

Heart failure (HF) is a major chronic illness and results in high morbidity and mortality. The most frequent cause of HF with reduced ejection fraction (HFREF) is coronary artery disease (CAD). Although revascularisation of ischemic myocardium lead to improvements in myocardial contractility and systolic function, it cannnot restore the viability of the already necrotic myocardium.

Methods/design

The aim of our prospective randomised study is to assess the efficacy of the retrograde application of non-selected bone marrow autologous cells concentrate (BMAC) in patients with HFREF of ischemic aetiology. The evaluated preparation is concentrated BMAC, obtained using Harvest SmartPReP2 (Harvest Technologies, Plymouth, MA, USA). The study population will be a total of 40 patients with established CAD, systolic dysfunction with LV EF of ≤40% and HF in the NYHA class 3. Patients have been on standard HF therapy for 3 months and in a stabilised state for at least 1 month, before enrolling in the clinical study. Patients will be randomised 1:1 to either retrograde BMAC administration via coronary sinus or standard HF therapy. The primary end-points (left ventricular end-systolic and end-diastolic diameters [LVESd/EDd] and volumes [LVESV/EDV] and left ventricular ejection fraction [LV EF]) will be assessed by magnetic resonance imaging. The follow-up period will be 12 month.

Discussion

The application of bone marrow stem cells into affected areas of the myocardium seems to be a promising treatment of ischemic cardiomyopathy.

The Harvest BMAC contains the entire population of nuclear cells from bone marrow aspirates together with platelets. The presence of both platelets and additional granulocytes can have a positive effect on the neovascularisation potential of the resulting concentrate. Our assumption is that retrograde administration on non-selected BMAC via coronary sinus, due to the content of platelets and growth factors, might improve left ventricular function and parameters compared to standard HF therapy. Furthermore, it will be associated with improved exercise tolerance in the six-minute corridor walk test and an improvement in the life quality of patients without increasing the incidence of severe ventricular arrythmias.

Trial registration

(ClinicalTrials.gov; https://clinicaltrials.gov; NCT03372954).

A multi-cellular 3D bioprinting approach for vascularized heart tissue engineering based on HUVECs and iPSC-derived cardiomyocytes

The myocardium behaves like a sophisticated orchestra that expresses its true potential only if each member performs the correct task harmonically. Recapitulating its complexity within engineered 3D functional constructs with tailored biological and mechanical properties, is one of the current scientific priorities in the field of regenerative medicine and tissue engineering. In this study, driven by the necessity of fabricating advanced model of cardiac tissue, we present an innovative approach consisting of heterogeneous, multi-cellular constructs composed of Human Umbilical Vein Endothelial Cells (HUVECs) and induced pluripotent cell-derived cardiomyocytes (iPSC-CMs). Cells were encapsulated within hydrogel strands containing alginate and PEG-Fibrinogen (PF) and extruded through a custom microfluidic printing head (MPH) that allows to precisely tailor their 3D spatial deposition, guaranteeing a high printing fidelity and resolution. We obtained a 3D cardiac tissue compose of iPSC-derived CMs with a high orientation index imposed by the different defined geometries and blood vessel-like shapes generated by HUVECs which, as demonstrated by in vivo grafting, better support the integration of the engineered cardiac tissue with host’s vasculature.

Characterizing the Key Metabolic Pathways of the Neonatal Mouse Heart Using a Quantitative Combinatorial Omics Approach

The heart of a newborn mouse has an exceptional capacity to regenerate from myocardial injury that is lost within the first week of its life. In order to elucidate the molecular mechanisms taking place in the mouse heart during this critical period we applied an untargeted combinatory multiomics approach using large-scale mass spectrometry-based quantitative proteomics, metabolomics and mRNA sequencing on hearts from 1-day-old and 7-day-old mice. As a result, we quantified 1.937 proteins (366 differentially expressed), 612 metabolites (263 differentially regulated) and revealed 2.586 differentially expressed gene loci (2.175 annotated genes). The analyses pinpointed the fructose-induced glycolysis-pathway to be markedly active in 1-day-old neonatal mice. Integrated analysis of the data convincingly demonstrated cardiac metabolic reprogramming from glycolysis to oxidative phosphorylation in 7-days old mice, with increases of key enzymes and metabolites in fatty acid transport (acylcarnitines) and β-oxidation. An upsurge in the formation of reactive oxygen species and an increase in oxidative stress markers, e.g., lipid peroxidation, altered sphingolipid and plasmalogen metabolism were also evident in 7-days mice. In vitro maintenance of physiological fetal hypoxic conditions retained the proliferative capacity of cardiomyocytes isolated from newborn mice hearts. In summary, we provide here a holistic, multiomics view toward early postnatal changes associated with loss of a tissue regenerative capacity in the neonatal mouse heart. These results may provide insight into mechanisms of human cardiac diseases associated with tissue regenerative incapacity at the molecular level, and offer a prospect to discovery of novel therapeutic targets.

[Stem cells: searching predisposition to cardiac commitment by surface markers expression]

It is well-known that cardiovascular diseases are the leading cause of death worldwide, and represent an important economic burden to health systems. In an attempt to solve this problem, stem cell therapy has emerged as a therapeutic option. Within the last 20 years, a great variety of stem cells have been used in different myocardial infarction models. Up until now, the use of cardiac stem cells (CSCs) has seemed to be the best option, but the inaccessibility and scarcity of these cells make their use unreliable. Additionally, there is a high risk as they have to be obtained directly from the heart of the patient. Unlike CSCs, adult stem cells originating from bone marrow or adipose tissue, among others, appear to be an attractive option due to their easier accessibility and abundance, but particularly due to the probable existence of cardiac progenitors among their different sub-populations. In this review an analysis is made of the surface markers present in CSCs compared with other adult stem cells. This suggested the pre-existence of cells sharing specific surface markers with CSCs, a predictable immunophenotype present in some cells, although in low proportions, and with a potential of cardiac differentiation that could be similar to CSCs, thus increasing their therapeutic value. This study highlights new perspectives regarding MSCs that would enable some of these sub-populations to be differentiated at cardiac tissue level.

Application of the allogenic mesenchymal stem cells in the therapy of the bladder tuberculosis

Urogenital tuberculosis (TB) often leads to contraction of the bladder, a reduction of the urinary reservoir capacity, and, in the latest stage, to real microcystitis up to full obliteration. Bladder TB Stage 4 is unsuitable for conservative therapy, and cystectomy with subsequent enteroplasty is indicated. In this study, using a model of bladder TB in New Zealand rabbits, the therapeutic efficacy of the interstitial injection of autologous bone-derived mesenchymal stem cells (MSCs) combined with standard anti-TB treatment in the restoration of the bladder function was demonstrated. For analysis of the MSC distribution in tissues, the latter were labelled with superparamagnetic iron oxide nanoparticles. In vitro studies demonstrated the high intracellular incorporation of nanoparticles and the absence of cytotoxicity on MSC viability and proliferation. A single-dose administration of MSCs into the bladder mucosal layer significantly reduced the wall deformation and inflammation and hindered the development of fibrosis, which was proven by the subsequent histological assay. Confocal microscopy studies of the bladder cryosections confirmed the presence of superparamagnetic iron oxide nanoparticle-labelled MSCs in different bladder layers of the treated animals, thus indicating the role of stem cells in bladder regeneration.

Advances in Monitoring Cell-Based Therapies with Magnetic Resonance Imaging: Future Perspectives

Cell-based therapies are currently being developed for applications in both regenerative medicine and in oncology. Preclinical, translational, and clinical research on cell-based therapies will benefit tremendously from novel imaging approaches that enable the effective monitoring of the delivery, survival, migration, biodistribution, and integration of transplanted cells. Magnetic resonance imaging (MRI) offers several advantages over other imaging modalities for elucidating the fate of transplanted cells both preclinically and clinically. These advantages include the ability to image transplanted cells longitudinally at high spatial resolution without exposure to ionizing radiation, and the possibility to co-register anatomical structures with molecular processes and functional changes. However, since cellular MRI is still in its infancy, it currently faces a number of challenges, which provide avenues for future research and development. In this review, we describe the basic principle of cell-tracking with MRI; explain the different approaches currently used to monitor cell-based therapies; describe currently available MRI contrast generation mechanisms and strategies for monitoring transplanted cells; discuss some of the challenges in tracking transplanted cells; and suggest future research directions.

New Treatment Strategies for Alcohol-Induced Heart Damage

High-dose alcohol misuse induces multiple noxious cardiac effects, including myocyte hypertrophy and necrosis, interstitial fibrosis, decreased ventricular contraction and ventricle enlargement. These effects produce diastolic and systolic ventricular dysfunction leading to congestive heart failure, arrhythmias and an increased death rate. There are multiple, dose-dependent, synchronic and synergistic mechanisms of alcohol-induced cardiac damage. Ethanol alters membrane permeability and composition, interferes with receptors and intracellular transients, induces oxidative, metabolic and energy damage, decreases protein synthesis, excitation-contraction coupling and increases cell apoptosis. In addition, ethanol decreases myocyte protective and repair mechanisms and their regeneration. Although there are diverse different strategies to directly target alcohol-induced heart damage, they are partially effective, and can only be used as support medication in a multidisciplinary approach. Alcohol abstinence is the preferred goal, but control drinking is useful in alcohol-addicted subjects not able to abstain. Correction of nutrition, ionic and vitamin deficiencies and control of alcohol-related systemic organ damage are compulsory. Recently, several growth factors (myostatin, IGF-1, leptin, ghrelin, miRNA, and ROCK inhibitors) and new cardiomyokines such as FGF21 have been described to regulate cardiac plasticity and decrease cardiac damage, improving cardiac repair mechanisms, and they are promising agents in this field. New potential therapeutic targets aim to control oxidative damage, myocyte hypertrophy, interstitial fibrosis and persistent apoptosis In addition, stem-cell therapy may improve myocyte regeneration. However, these strategies are not yet approved for clinical use.