Paracrine Mechanisms Involved in Mesenchymal Stem Cell Differentiation into Cardiomyocytes

Functional Roles of Mesenchymal Stem Cell-derived Exosomes in Ischemic Stroke Treatment

Stroke is a life-threatening disease and one of the leading causes of death and physical disability worldwide. Currently, no drugs on the market promote neural recovery after stroke insult, and spontaneous remodeling processes are limited to induce recovery in the ischemic regions. Therefore, promoting a cell-based therapy has been needed to elevate the endogenous recovery process. Mesenchymal stem cells (MSCs) have been regarded as candidate cell sources for therapeutic purposes of ischemic stroke, and their therapeutic effects are mediated by exosomes. The microRNA cargo in these extracellular vesicles is mostly responsible for the positive effects. When it comes to the therapeutic viewpoint, MSCsderived exosomes could be a promising therapeutic strategy against ischemic stroke. The aim of this review is to discuss the current knowledge around the potential of MSCs-derived exosomes in the treatment of ischemic stroke.

The recent advances in cell delivery approaches, biochemical and engineering procedures of cell therapy applied to coronary heart disease

Cell therapy is an important topic in the field of regeneration medicine that is gaining attention within the scientific community. However, its potential for treatment in coronary heart disease (CHD) has yet to be established. Several various strategies, types of cells, routes of distribution, and supporting procedures have been tried and refined to trigger heart rejuvenation in CHD. However, only a few of them result in a real considerable promise for clinical usage. In this review, we give an update on techniques and clinical studies of cell treatment as used to cure CHD that are now ongoing or have been completed in the previous five years. We also highlight the emerging efficacy of stem cell treatment for CHD. We specifically examine and comment on current breakthroughs in cell treatment applied to CHD, including the most effective types of cells, transport modalities, engineering, and biochemical approaches used in this context. We believe the current review will be helpful for the researcher to distill this information and design future studies to overcome the challenges faced by this revolutionary approach for CHD.

Upregulation of Reg IV and Hgf mRNAs by Intermittent Hypoxia via Downregulation of microRNA-499 in Cardiomyocytes

Sleep apnea syndrome (SAS) is characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]), and is a risk factor for cardiovascular disease (CVD) and insulin resistance/Type 2 diabetes. However, the mechanisms linking IH stress and CVD remain elusive. We exposed rat H9c2 and mouse P19.CL6 cardiomyocytes to experimental IH or normoxia for 24 h to analyze the mRNA expression of several cardiomyokines. We found that the mRNA levels of regenerating gene IV (Reg IV) and hepatocyte growth factor (Hgf) in H9c2 and P19.CL6 cardiomyocytes were significantly increased by IH, whereas the promoter activities of the genes were not increased. A target mRNA search of microRNA (miR)s revealed that rat and mouse mRNAs have a potential target sequence for miR-499. The miR-499 level of IH-treated cells was significantly decreased compared to normoxia-treated cells. MiR-499 mimic and non-specific control RNA (miR-499 mimic NC) were introduced into P19.CL6 cells, and the IH-induced upregulation of the genes was abolished by introduction of the miR-499 mimic, but not by the miR-499 mimic NC. These results indicate that IH stress downregulates the miR-499 in cardiomyocytes, resulting in increased levels of Reg IV and Hgf mRNAs, leading to the protection of cardiomyocytes in SAS patients.

Pre-Conditioning Methods and Novel Approaches with Mesenchymal Stem Cells Therapy in Cardiovascular Disease

Transplantation of mesenchymal stem cells (MSCs) in the setting of cardiovascular disease, such as heart failure, cardiomyopathy and ischemic heart disease, has been associated with good clinical outcomes in several trials. A reduction in left ventricular remodeling, myocardial fibrosis and scar size, an improvement in endothelial dysfunction and prolonged cardiomyocytes survival were reported. The regenerative capacity, in addition to the pro-angiogenic, anti-apoptotic and anti-inflammatory effects represent the main target properties of these cells. Herein, we review the different preconditioning methods of MSCs (hypoxia, chemical and pharmacological agents) and the novel approaches (genetically modified MSCs, MSC-derived exosomes and engineered cardiac patches) suggested to optimize the efficacy of MSC therapy.

Effectiveness of cell- and colony stimulating factor-based therapy for liver cirrhosis: a network meta-analysis of randomized controlled trials

BACKGROUND AIMS

Cirrhosis is the 11th leading cause of death worldwide. Because of the limitations of liver transplantation, cell- and granulocyte colony-stimulating factor (G-CSF)-based therapies are considered potential treatment methods. This work analyzes the effectiveness of cell- and G-CSF-based therapies by network meta-analysis.

METHODS

A literature search was performed in four databases from inception to September 10, 2021. Registered randomized controlled trials (RCTs) evaluating cell-based therapies and/or G-CSF-based therapies for cirrhosis patients were included. Traditional and network meta-analyses were analyzed in terms of survival, model for end-stage liver disease (MELD) score, Child-Turcotte-Pugh (CTP) score, alanine aminotransferase levels and aspartate aminotransferase levels.

RESULTS

Twenty-four studies were included in this analysis. The results showed that G-CSF-based therapies (odds ratio [OR], 2.38, 95% confidence interval [CI], 1.49-3.79, P < 0.01) and cell-based therapies (OR, 1.54, 95% CI, 1.00-2.40, P = 0.048) improved the transplantation-free survival rate compared with standard medical treatment. Network analysis results showed that G-CSF combined with erythropoietin (EPO) and growth hormone (GH) had a therapeutic advantage, and cell-based therapy with mononuclear cell (MNC) hepatic artery injection and intravenous mesenchymal stem cells (MSCs) combined with G-CSF also had a relative advantage in terms of survival outcome. For the MELD score, G-CSF plus GH and MSC portal vein injection had relative advantages. G-CSF plus GH and G-CSF plus EPO had advantages in terms of CTP scores. The included strategies demonstrated no obvious improvement in liver injury indicators.

CONCLUSIONS

Cell-based therapy has potential therapeutic effects for liver cirrhosis. Among cell-based therapies, intravenous MSCs and hepatic artery injection of MNCs have advantageous therapeutic effects. The use of G-CSF was also noted in regimens that improved survival outcomes. However, more well-designed, large-scale RCTs are needed to confirm this conclusion.

Mechanotransduction in Mesenchymal Stem Cells (MSCs) Differentiation: A Review

Mechanotransduction is the process by which physical force is converted into a biochemical signal that is used in development and physiology; meanwhile, it is intended for the ability of cells to sense and respond to mechanical forces by activating intracellular signals transduction pathways and the relative phenotypic adaptation. It encompasses the role of mechanical stimuli for developmental, morphological characteristics, and biological processes in different organs; the response of cells to mechanically induced force is now also emerging as a major determinant of disease. Due to fluid shear stress caused by blood flowing tangentially across the lumen surface, cells of the cardiovascular system are typically exposed to a variety of mechanotransduction. In the body, tissues are continuously exposed to physical forces ranging from compression to strain, which is caused by fluid pressure and compressive forces. Only lately, though, has the importance of how forces shape stem cell differentiation into lineage-committed cells and how mechanical forces can cause or exacerbate disease besides organizing cells into tissues been acknowledged. Mesenchymal stem cells (MSCs) are potent mediators of cardiac repair which can secret a large array of soluble factors that have been shown to play a huge role in tissue repair. Differentiation of MSCs is required to regulate mechanical factors such as fluid shear stress, mechanical strain, and the rigidity of the extracellular matrix through various signaling pathways for their use in regenerative medicine. In the present review, we highlighted mechanical influences on the differentiation of MSCs and the general factors involved in MSCs differentiation. The purpose of this study is to demonstrate the progress that has been achieved in understanding how MSCs perceive and react to their mechanical environment, as well as to highlight areas where more research has been performed in previous studies to fill in the gaps.

Functions of Mesenchymal Stem Cells in Cardiac Repair

Myocardial infarction (MI) and heart failure (HF) are significant contributors of mortality worldwide. Mesenchymal stem cells (MSCs) hold a great potential for cardiac regenerative medicine-based therapies. Their therapeutic potential has been widely investigated in various in-vitro and in-vivo preclinical models. Besides, they have been tested in clinical trials of MI and HF with various outcomes. Differentiation to lineages of cardiac cells, neovascularization, anti-fibrotic, anti-inflammatory, anti-apoptotic and immune modulatory effects are the main drivers of MSC functions during cardiac repair. However, the main mechanisms regulating these functions and cross-talk between cells are not fully known yet. Increasing line of evidence also suggests that secretomes of MSCs and/or their extracellular vesicles play significant roles in a paracrine manner while mediating these functions. This chapter aims to summarize and highlight cardiac repair functions of MSCs during cardiac repair.

The Current Dilemma and Breakthrough of Stem Cell Therapy in Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of mortality worldwide. Stem cell transplantation has become a promising approach for the treatment of IHD in recent decades. It is generally recognized that preclinical cell-based therapy is effective and have yielded encouraging results, which involves preventing or reducing myocardial cell death, inhibiting scar formation, promoting angiogenesis, and improving cardiac function. However, clinical studies have not yet achieved a desired outcome, even multiple clinical studies showing paradoxical results. Besides, many fundamental puzzles remain to be resolved, for example, what is the optimal delivery timing and approach? Additionally, limited cell engraftment and survival, challenging cell fate monitoring, and not fully understood functional mechanisms are defined hurdles to clinical translation. Here we review some of the current dilemmas in stem cell-based therapy for IHD, along with our efforts and opinions on these key issues.

WNT signaling in atrial fibrillation

The Wnt signaling pathway regulates physiological processes such as cell proliferation and differentiation, cell fate decisions, and stem cell maintenance and, thus, plays essential roles in embryonic development, but also in adult tissue homeostasis and repair. The Wnt signaling pathway has been associated with heart development and repair and has been shown to be crucially involved in proliferation and differentiation of progenitor cells into cardiomyocytes. The investigation of the role of the Wnt signaling pathway and the regulation of its expression/activity in atrial fibrillation has only just begun. The present minireview (I) provides original data regarding the expression of Wnt signaling components in atrial tissue of patients with atrial fibrillation or sinus rhythm and (II) summarizes the current state of knowledge of the regulation of Wnt signaling components' expression/activity and the contribution of the various levels of the Wnt signal transduction pathway to the processes of the development, maintenance, and progression of atrial fibrillation.

Human Mesenchymal Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI), as a devastating and life-altering neurological disorder, is one of the most serious health issues. Currently, the management of acute SCI includes pharmacotherapy and surgical decompression. Both the approaches have been observed to have adverse physiological effects on SCI patients. Therefore, novel therapeutic targets for the management of SCI are urgently required for developing cell-based therapies. Multipotent stem cells, as a novel strategy for the treatment of tissue injury, may provide an effective therapeutic option against many neurological disorders. Mesenchymal stem cells (MSCs) or multipotent stromal cells can typically self-renew and generate various cell types. These cells are often isolated from bone marrow (BM-MSCs), adipose tissues (AD-MSCs), umbilical cord blood (UCB-MSCs), and placenta (PMSCs). MSCs have remarkable potential for the development of regenerative therapies in animal models and humans with SCI. Herein, we summarize the therapeutic potential of human MSCs in the treatment of SCI.

Human Pluripotent Stem Cells for Spinal Cord Injury

Spinal cord injury (SCI) as a serious public health issue and neurological insult is one of the most severe cause of long-term disability. To date, a variety of techniques have been widely developed to treat central nervous system injury. Currently, clinical treatments are limited to surgical decompression and pharmacotherapy. Because of their negative effects and inefficiency, novel therapeutic approaches are required in the management of SCI. Improvement and innovation of stem cell-based therapies have a huge potential for biological and future clinical applications. Human pluripotent stem cells (hPSCs) including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are defined by their abilities to divide asymmetrically, self-renew and ultimately differentiate into various cell lineages. There are considerable research efforts to use various types of stem cells, such as ESCs, neural stem cells (NSCs), and mesenchymal stem cells (MSCs) in the treatment of patients with SCI. Moreover, the use of patient-specific iPSCs holds great potential as an unlimited cell source for generating in vivo models of SCI. In this review, we focused on the potential of hPSCs in treating SCI.

Preconditioned and Genetically Modified Stem Cells for Myocardial Infarction Treatment

Ischemic heart disease and myocardial infarction remain leading causes of mortality worldwide. Existing myocardial infarction treatments are incapable of fully repairing and regenerating the infarcted myocardium. Stem cell transplantation therapy has demonstrated promising results in improving heart function following myocardial infarction. However, poor cell survival and low engraftment at the harsh and hostile environment at the site of infarction limit the regeneration potential of stem cells. Preconditioning with various physical and chemical factors, as well as genetic modification and cellular reprogramming, are strategies that could potentially optimize stem cell transplantation therapy for clinical application. In this review, we discuss the most up-to-date findings related to utilizing preconditioned stem cells for myocardial infarction treatment, focusing mainly on preconditioning with hypoxia, growth factors, drugs, and biological agents. Furthermore, genetic manipulations on stem cells, such as the overexpression of specific proteins, regulation of microRNAs, and cellular reprogramming to improve their efficiency in myocardial infarction treatment, are discussed as well.

Mesenchymal Stem Cell-Mediated Mitochondrial Transfer: a Therapeutic Approach for Ischemic Stroke

Stroke is the leading cause of death and adult disability worldwide. Mitochondrial dysfunction is one of the hallmarks of stroke-induced neuronal death, and maintaining mitochondrial function is essential in cell survival and neurological progress following ischemic stroke. Stem cell-mediated mitochondrial transfer represents an emerging therapeutic approach for ischemic stroke. Accumulating evidence suggests that mesenchymal stem cells (MSCs) can directly transfer healthy mitochondria to damaged cells, and rescue mitochondrial damage-provoked tissue degeneration. This review summarizes the research on MSCs-mediated mitochondrial transfer as a therapeutic strategy against ischemic stroke.

Small G protein signaling modulator 3 (SGSM3) knockdown attenuates apoptosis and cardiogenic differentiation in rat mesenchymal stem cells exposed to hypoxia

Connexin 43 (Cx43) may be important in cell death and survival due to cell-to-cell communication-independent mechanisms. In our previous study, we found that small G protein signaling modulator 3 (SGSM3), a partner of Cx43, contributes to myocardial infarction (MI) in rat hearts. Based on these previous results, we hypothesized that SGSM3 could also play a role in bone marrow-derived rat mesenchymal stem cells (MSCs), which differentiate into cardiomyocytes and/or cells with comparable phenotypes under low oxygen conditions. Cx43 and Cx43-related factor expression profiles were compared between normoxic and hypoxic conditions according to exposure time, and Sgsm3 gene knockdown (KD) using siRNA transfection was performed to validate the interaction between SGSM3 and Cx43 and to determine the roles of SGSM3 in rat MSCs. We identified that SGSM3 interacts with Cx43 in MSCs under different oxygen conditions and that Sgsm3 knockdown inhibits apoptosis and cardiomyocyte differentiation under hypoxic stress. SGSM3/Sgsm3 probably has an effect on MSC survival and thus therapeutic potential in diseased hearts, but SGSM3 may worsen the development of MSC-based therapeutic approaches in regenerative medicine. This study was performed to help us better understand the mechanisms involved in the therapeutic efficacy of MSCs, as well as provide data that could be used pharmacologically.

Decellularized Human Dermal Matrix as a Biological Scaffold for Cardiac Repair and Regeneration

The complex and highly organized environment in which cells reside consists primarily of the extracellular matrix (ECM) that delivers biological signals and physical stimuli to resident cells. In the native myocardium, the ECM contributes to both heart compliance and cardiomyocyte maturation and function. Thus, myocardium regeneration cannot be accomplished if cardiac ECM is not restored. We hypothesize that decellularized human skin might make an easily accessible and viable alternate biological scaffold for cardiac tissue engineering (CTE). To test our hypothesis, we decellularized specimens of both human skin and human myocardium and analyzed and compared their composition by histological methods and quantitative assays. Decellularized dermal matrix was then cut into 600-μm-thick sections and either tested by uniaxial tensile stretching to characterize its mechanical behavior or used as three-dimensional scaffold to assess its capability to support regeneration by resident cardiac progenitor cells (hCPCs) in vitro. Histological and quantitative analyses of the dermal matrix provided evidence of both effective decellularization with preserved tissue architecture and retention of ECM proteins and growth factors typical of cardiac matrix. Further, the elastic modulus of the dermal matrix resulted comparable with that reported in literature for the human myocardium and, when tested in vitro, dermal matrix resulted a comfortable and protective substrate promoting and supporting hCPC engraftment, survival and cardiomyogenic potential. Our study provides compelling evidence that dermal matrix holds promise as a fully autologous and cost-effective biological scaffold for CTE.

Mitochondria as a therapeutic target for ischemic stroke

Stroke is the leading cause of death and physical disability worldwide. Mitochondrial dysfunction has been considered as one of the hallmarks of ischemic stroke and contributes to the pathology of ischemia and reperfusion. Mitochondria is essential in promoting neural survival and neurological improvement following ischemic stroke. Therefore, mitochondria represent an important drug target for stroke treatment. This review discusses the mitochondrial molecular mechanisms underlying cerebral ischemia and involved in reactive oxygen species generation, mitochondrial electron transport dysfunction, mitochondria-mediated regulation of inflammasome activation, mitochondrial dynamics and biogenesis, and apoptotic cell death. We highlight the potential of mitochondrial transfer by stem cells as a therapeutic target for stroke treatment and provide valuable insights for clinical strategies. A better understanding of the roles of mitochondria in ischemia-induced cell death and protection may provide a rationale design of novel therapeutic interventions in the ischemic stroke.

Therapeutic Potential of “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling: Exosomes d-MAPPS” is Based on the Effects of Exosomes, Immunosuppressive and Trophic Factors

Due to their differentiation capacity and potent immunosuppressive and pro-angiogenic properties, mesenchymal stem cells (MSCs) have been considered as new therapeutic agents in regenerative medicine. Since most of MSC-mediated beneficent effects are a consequence of their paracrine action, we designed MSC-based product “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling (Exosomes d-MAPPS), which activity is based on MSCs-derived growth factors and immunomodulatory cytokines capable to attenuate inflammation and to promote regeneration of injured tissues. Interleukin 1 receptor antagonist (IL-1Ra) and IL-27 were found in high concentrations in Exosomes d-MAPPS samples indicating strong anti-inflammatory and immunosuppressive potential of Exosomes d-MAPPS. Additionally, high concentrations of vascular endothelial growth factor receptor (VEGFR1) and chemokines (CXCL16, CCL21, CXCL14) were noticed at Exosomes d-MAPPS samples suggesting their potential to promote generation of new blood vessels and migration of CXCR6, CCR7 and CXCR4 expressing cells. Since all proteins which were found in high concentration in Exosomes d-MAPPS samples (IL-1Ra, CXCL16, CXCL14, CCL21, IL-27 and VEGFR1) are involved in modulation of lung, eye, and synovial inflammation, Exosomes d-MAPPS samples were prepared as inhalation and ophthalmic solutions in addition to injection formulations; their application in several patients suffering from chronic obstructive pulmonary disease, osteoarthritis, and dry eye syndrome resulted with significant improvement of biochemical and functional parameters. In conclusion, Exosomes d-MAPPS, due to the presence of important anti-inflammatory, immunomodulatory, and pro-angiogenic factors, represents potentially new therapeutic agent in regenerative medicine that should be further tested in large clinical studies.

Cardiac tissue engineering: state-of-the-art methods and outlook

The purpose of this review is to assess the state-of-the-art fabrication methods, advances in genome editing, and the use of machine learning to shape the prospective growth in cardiac tissue engineering. Those interdisciplinary emerging innovations would move forward basic research in this field and their clinical applications. The long-entrenched challenges in this field could be addressed by novel 3-dimensional (3D) scaffold substrates for cardiomyocyte (CM) growth and maturation. Stem cell-based therapy through genome editing techniques can repair gene mutation, control better maturation of CMs or even reveal its molecular clock. Finally, machine learning and precision control for improvements of the construct fabrication process and optimization in tissue-specific clonal selections with an outlook of cardiac tissue engineering are also presented.

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Promote Fibroblast-to-Myofibroblast Differentiation in Inflammatory Environments and Benefit Cardioprotective Effects

Cardioprotective effects of exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-exosomes) postmyocardial infarction (post-MI) have been reported in our previous study. It is known that fibroblasts are pro-inflammatory phenotypes, while myofibroblasts are anti-inflammatory phenotypes. This study aimed to investigate whether hucMSC-exosomes promoted cardiac fibroblast-to-myofibroblast differentiation in inflammatory environments and protected cardiomyocytes. Rats were performed by permanent ligation of the left anterior descending coronary artery and underwent intramyocardial injection of hucMSC-exosomes or phosphate-buffered saline (PBS) in surgery. Fibroblasts were stimulated by lipopolysaccharide (LPS) to create inflammatory environments in vitro. Western blot and immunohistochemical and immunofluorescence staining for α-smooth muscle actin were used to demonstrate fibroblast-to-myofibroblast differentiation. Transwell migration assay and CCK-8 assay were used to evaluate migration and proliferation of fibroblasts. Reverse transcription-polymerase chain reaction, western blot, and immunohistochemical staining were used to detect expressions of inflammatory factors. To investigate cardioprotective effects, cardiomyocytes were treated with supernatant derived from fibroblasts pretreated with LPS or LPS plus hucMSC-exosomes in hypoxic environments. Cardiomyocyte apoptosis was determined using TUNEL assay and western blot. Results indicated that hucMSC-exosomes increased the density of myofibroblasts in infarct areas during inflammatory phases post-MI, promoted fibroblast-to-myofibroblast differentiation in inflammatory environments, and attenuated inflammatory responses in vitro and in vivo. Culture medium derived from fibroblasts pretreated with LPS plus hucMSC-exosomes reduced cardiomyocyte apoptosis. In vivo, apoptotic cells in acute myocardial infarction (AMI)+exosomes groups were also less than AMI+PBS groups. In conclusion, hucMSC-exosomes can promote fibroblast-to-myofibroblast differentiation in inflammatory environments, then protecting cardiomyocytes.

Notch signal pathway - therapeutic target for regulation of reparative processes in the heart

Notch signaling pathway is a universal regulator of cell fate in embryogenesis and in maintaining the cell homeostasis of adult tissue. Through local cell-cell interactions, he controls neighboring cells behavior and determines their capacity for self-renewal, growth, survival, differentiation, and apoptosis. Recent studies have shown that the control of regenerative processes in the heart is also carried out with the participation of Notch system. At the heart of Notch regulates migration bone marrow progenitors and stimulates the proliferation of cardiomyocytes, cardiac progenitor cell activity, limits cardiomyocyte hypertrophy and fibrosis progression and stimulates angiogenesis. Notch signaling pathway may be regarded as a very promising target for the development of drugs for the stimulation of regeneration in the myocardium.