Pharmacological preconditioning of mesenchymal stem cells with trimetazidine (1-[2,3,4-trimethoxybenzyl]piperazine) protects hypoxic cells against oxidative stress and enhances recovery of myocardial function in infarcted heart through Bcl-2 expression

New insights on pharmacological and therapeutic potentials of trimetazidine beyond anti-anginal drug: A comprehensive review

Trimetazidine (TMZ) is a beneficial and well-tolerable anti-anginal drug which has protective action towards ischemia and reperfusion injury. TMZ performs its anti-ischemic effect by modifying cardiac metabolism without shifting the hemodynamic functions, so it represents an outstanding complementary perspective to the general angina treatment. TMZ possesses a positive impact on the inflammatory profile, and also endothelial function furthermore displays various benefits through minimising the number, as well as the intensity of angina strikes and ameliorating the clinical indication and symptoms of myocardium ischemia. It is administrated as monotherapy along with a combination of different antianginal drugs. Apart from anti-angina action, in recent years TMZ has shown various pharmacological activities such as neuroprotective, renal protective, hepato-protective, cardio-protective effects, and other beneficial pharmacological activities. We select to write the present review article to cover the different pharmacological and therapeutic potentials of TMZ.

Emerging Strategies in Mesenchymal Stem Cell-Based Cardiovascular Therapeutics

Cardiovascular diseases continue to challenge global health, demanding innovative therapeutic solutions. This review delves into the transformative role of mesenchymal stem cells (MSCs) in advancing cardiovascular therapeutics. Beginning with a historical perspective, we trace the development of stem cell research related to cardiovascular diseases, highlighting foundational therapeutic approaches and the evolution of cell-based treatments. Recognizing the inherent challenges of MSC-based cardiovascular therapeutics, which range from understanding the pro-reparative activity of MSCs to tailoring patient-specific treatments, we emphasize the need to refine the pro-regenerative capacity of these cells. Crucially, our focus then shifts to the strategies of the fourth generation of cell-based therapies: leveraging the secretomic prowess of MSCs, particularly the role of extracellular vesicles; integrating biocompatible scaffolds and artificial sheets to amplify MSCs' potential; adopting three-dimensional ex vivo propagation tailored to specific tissue niches; harnessing the promise of genetic modifications for targeted tissue repair; and institutionalizing good manufacturing practice protocols to ensure therapeutic safety and efficacy. We conclude with reflections on these advancements, envisaging a future landscape redefined by MSCs in cardiovascular regeneration. This review offers both a consolidation of our current understanding and a view toward imminent therapeutic horizons.

Injectable hydrogel-based combination therapy for myocardial infarction: a systematic review and Meta-analysis of preclinical trials

INTRODUCTION

This study evaluates the effectiveness of a combined regimen involving injectable hydrogels for the treatment of experimental myocardial infarction.

PATIENT CONCERNS

Myocardial infarction is an acute illness that negatively affects quality of life and increases mortality rates. Experimental models of myocardial infarction can aid in disease research by allowing for the development of therapies that effectively manage disease progression and promote tissue repair.

DIAGNOSIS

Experimental animal models of myocardial infarction were established using the ligation method on the anterior descending branch of the left coronary artery (LAD).

INTERVENTIONS

The efficacy of intracardiac injection of hydrogels, combined with cells, drugs, cytokines, extracellular vesicles, or nucleic acid therapies, was evaluated to assess the functional and morphological improvements in the post-infarction heart achieved through the combined hydrogel regimen.

OUTCOMES

A literature review was conducted using PubMed, Web of Science, Scopus, and Cochrane databases. A total of 83 papers, including studies on 1332 experimental animals (rats, mice, rabbits, sheep, and pigs), were included in the meta-analysis based on the inclusion and exclusion criteria. The overall effect size observed in the group receiving combined hydrogel therapy, compared to the group receiving hydrogel treatment alone, resulted in an ejection fraction (EF) improvement of 8.87% [95% confidence interval (CI): 7.53, 10.21] and a fractional shortening (FS) improvement of 6.31% [95% CI: 5.94, 6.67] in rat models, while in mice models, the improvements were 16.45% [95% CI: 11.29, 21.61] for EF and 5.68% [95% CI: 5.15, 6.22] for FS. The most significant improvements in EF (rats: MD = 9.63% [95% CI: 4.02, 15.23]; mice: MD = 23.93% [95% CI: 17.52, 30.84]) and FS (rats: MD = 8.55% [95% CI: 2.54, 14.56]; mice: MD = 5.68% [95% CI: 5.15, 6.22]) were observed when extracellular vesicle therapy was used. Although there have been significant results in large animal experiments, the number of studies conducted in this area is limited.

CONCLUSION

The present study demonstrates that combining hydrogel with other therapies effectively improves heart function and morphology. Further preclinical research using large animal models is necessary for additional study and validation.

Breaking the graft-versus-host-disease barrier: Mesenchymal stromal/stem cells as precision healers

Mesenchymal Stromal/Stem Cells (MSCs) are multipotent, non-hematopoietic progenitor cells with a wide range of immune modulation and regenerative potential which qualify them as a potential component of cell-based therapy for various autoimmune/chronic inflammatory ailments. Their immunomodulatory properties include the secretion of immunosuppressive cytokines, the ability to suppress T-cell activation and differentiation, and the induction of regulatory T-cells. Considering this and our interest, we here discuss the significance of MSC for the management of Graft-versus-Host-Disease (GvHD), one of the autoimmune manifestations in human. In pre-clinical models, MSCs have been shown to reduce the severity of GvHD symptoms, including skin and gut damage, which are the most common and debilitating manifestations of this disease. While initial clinical studies of MSCs in GvHD cases were promising, the results were variable in randomized studies. So, further studies are warranted to fully understand their potential benefits, safety profile, and optimal dosing regimens. Owing to these inevitable issues, here we discuss various mechanisms, and how MSCs can be employed in managing GvHD, as a cellular therapeutic approach for this disease.

Trimetazidine Preconditioning Potentiates the Effect of Mesenchymal Stem Cells Secretome on the Preservation of Rat Pancreatic Islet Survival and Function In Vitro

Islet transplantation offers improved glycemic control in individuals with type 1 diabetes mellitus. However, in vitro islet culture is associated with islet apoptosis and eventually will lose their functionality prior to transplantation. In this study, we examined the effects of mesenchymal stem cells (MSCs) secretome preconditioned with diazoxide (DZ) and trimetazidine (TMZ) on rat islet cells during pre-transplant culture. With and without preconditioned hAD-MSCs' concentrated conditioned media (CCM) were added to the culture medium containing rat islets every 12 h for 24 and 48 h, after testing for selected cytokine concentrations (interleukin (IL)-4, IL-6, IL-13). Insulin content, glucose-stimulated insulin secretion, islet cell apoptosis, and mRNA expression of pro-apoptotic (BAX, BAK-1, and PUMA) and anti-apoptotic factors (BCL-2, BCL-xL, and XIAP) in rat islets were assessed after 24 and 48 h of culture. The protein level of IL-6 and IL-4 was significantly higher in TMZ-MSC-CM compared to MSC-non-CM. In rat isolated islets, normalized secreted insulin in the presence of 16.7 mM glucose was significantly higher in treated islet groups compared to control islets at both 24 and 48 h cultivation. Also, the percentage of apoptotic islet cells TMZ-MSC-CCM-treated islets was significantly lower compared to MSC-CM and MSC-CCM-treated islets in both 24 and 48 h cultivation. Consistent with the number of apoptotic cells, after 24 h culture, the expression of BCL-2 and BCL-xL genes in the control islets was lower than all treatment islet groups and in 48 h was lower than only TMZ-MSC-CM-treated islets. Also, the expression of the XIAP gene in control islets was significantly lower compared to the TMZ-MSC-CCM-treated islets at both at 24 and 48 h. In addition, mRNA level of the BAX gene in TMZ-MSC-CCM-treated islets was significantly lower compared to other groups at 48 h. Our findings revealed that TMZ proved to be more effective than DZ and could enhance the potential of hAD-MSCs-CM to improve the function and viability of islets prior to transplantation.

Potential pre-activation strategies for improving therapeutic efficacy of mesenchymal stem cells: current status and future prospects

Mesenchymal stem cell (MSC)-based therapy has been considered as a promising approach targeting a variety of intractable diseases due to remarkable multiple effect of MSCs, such as multilineage differentiation, immunomodulatory property, and pro-regenerative capacity. However, poor engraftment, low survival rate of transplanted MSC, and impaired donor-MSC potency under host age/disease result in unsatisfactory therapeutic outcomes. Enhancement strategies, including genetic manipulation, pre-activation, and modification of culture method, have been investigated to generate highly functional MSC, and approaches for MSC pre-activation are highlighted. In this review, we summarized the current approaches of MSC pre-activation and further classified, analysed the scientific principles and main characteristics of these manipulations, and described the pros and cons of individual pre-activation strategies. We also discuss the specialized tactics to solve the challenges in this promising field so that it improves MSC therapeutic functions to serve patients better.

State of the field: cellular and exosomal therapeutic approaches in vascular regeneration

Pathologies of the vasculature including the microvasculature are often complex in nature, leading to loss of physiological homeostatic regulation of patency and adequate perfusion to match tissue metabolic demands. Microvascular dysfunction is a key underlying element in the majority of pathologies of failing organs and tissues. Contributing pathological factors to this dysfunction include oxidative stress, mitochondrial dysfunction, endoplasmic reticular (ER) stress, endothelial dysfunction, loss of angiogenic potential and vascular density, and greater senescence and apoptosis. In many clinical settings, current pharmacologic strategies use a single or narrow targeted approach to address symptoms of pathology rather than a comprehensive and multifaceted approach to address their root cause. To address this, efforts have been heavily focused on cellular therapies and cell-free therapies (e.g., exosomes) that can tackle the multifaceted etiology of vascular and microvascular dysfunction. In this review, we discuss 1) the state of the field in terms of common therapeutic cell population isolation techniques, their unique characteristics, and their advantages and disadvantages, 2) common molecular mechanisms of cell therapies to restore vascularization and/or vascular function, 3) arguments for and against allogeneic versus autologous applications of cell therapies, 4) emerging strategies to optimize and enhance cell therapies through priming and preconditioning, and, finally, 5) emerging strategies to bolster therapeutic effect. Relevant and recent clinical and animal studies using cellular therapies to restore vascular function or pathologic tissue health by way of improved vascularization are highlighted throughout these sections.

Modulation of Mesenchymal Stem Cells for Enhanced Therapeutic Utility in Ischemic Vascular Diseases

Mesenchymal stem cells are multipotent stem cells isolated from various tissue sources, including but not limited to bone marrow, adipose, umbilical cord, and Wharton Jelly. Although cell-mediated mechanisms have been reported, the therapeutic effect of MSCs is now recognized to be primarily mediated via paracrine effects through the secretion of bioactive molecules, known as the “secretome”. The regenerative benefit of the secretome has been attributed to trophic factors and cytokines that play neuroprotective, anti-angiogenic/pro-angiogenic, anti-inflammatory, and immune-modulatory roles. The advancement of autologous MSCs therapy can be hindered when introduced back into a hostile/disease environment. Barriers include impaired endogenous MSCs function, limited post-transplantation cell viability, and altered immune-modulatory efficiency. Although secretome-based therapeutics have gained popularity, many translational hurdles, including the heterogeneity of MSCs, limited proliferation potential, and the complex nature of the secretome, have impeded the progress. This review will discuss the experimental and clinical impact of restoring the functional capabilities of MSCs prior to transplantation and the progress in secretome therapies involving extracellular vesicles. Modulation and utilization of MSCs–secretome are most likely to serve as an effective strategy for promoting their ultimate success as therapeutic modulators.

Trimetazidine ameliorates hindlimb ischaemic damage in type 2 diabetic mice

BACKGROUND

Ischaemia caused by lower extremity artery stenosis is the main cause of peripheral artery disease (PAD) in patients with diabetes. Trimetazidine (TMZ) has traditionally been used as an anti-ischaemic drug for coronary artery disease. The effect of TMZ on PAD in a diabetic animal model and the underlying molecular mechanisms remain unclear.

METHODS

The db/db mice were challenged with femoral artery ligation (FAL), followed by TMZ treatment for 2 weeks. Scores on hindlimb ischaemia and function were evaluated. Histological and capillary density analyses of gastrocnemius were performed. The expression of vascular endothelial growth factor (VEGF) and myogenic regulators was also confirmed by Western blotting. We also detected serum intercellular adhesion molecule 1 (ICAM-1) level through ELISA.

RESULTS

Diabetic mice exhibited limb ulceration and motor dysfunction after FAL while TMZ-treated db/db mice exhibited milder ischaemic impairment. Furthermore, decreased capillary density in the gastrocnemius muscles of ischaemic hindlimb and reduced expressions of VEGF, myogenic markers, and serum ICAM-1 could be partially reversed by TMZ treatment.

CONCLUSION

TMZ may alleviate hindlimb ischaemic damage in db/db mice, at least partly, through enhancing angiogenesis and promoting myogenesis in ischaemia region.Key messagesTMZ intervention could alleviate hindlimb ischaemic damage in db/db mice.TMZ intervention could enhance angiogenesis and stimulate myogenesis in ischaemia region.

Hopes and Hurdles of Employing Mesenchymal Stromal Cells in the Treatment of Cardiac Fibrosis

Excessive cardiac fibrosis plays a crucial role in almost all types of heart disease. Generally, cardiac fibrosis is a scarring process triggered in response to stress, injury, or aging and is characterized by the accumulation of activated myofibroblasts that deposit high levels of extracellular matrix proteins in the myocardium. While it is beneficial for cardiac repair in the short term, it can also result in pathological remodeling, tissue stiffening, and cardiac dysfunction, contributing to the progression of heart failure, arrhythmia, and sudden cardiac death. Despite its high prevalence, there is a lack of effective and safe therapies that specifically target myofibroblasts to inhibit or even reverse pathological cardiac fibrosis. In the past few decades, cell therapy has been under continuous evaluation as a potential treatment strategy, and several studies have shown that transplantation of mesenchymal stromal cells (MSCs) can reduce cardiac fibrosis and improve heart function. Mechanistically, it is believed that the heart benefits from MSC therapy by stimulating innate anti-fibrotic and regenerative reactions. The mechanisms of action include paracrine signaling and cell-to-cell interactions. In this review, we provide an overview of the anti-fibrotic properties of MSCs and approaches to enhance them and discuss future directions of MSCs for the treatment of cardiac fibrosis.

Perspective on Stem Cell Therapy in Organ Fibrosis: Animal Models and Human Studies

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) components that result from the disruption of regulatory processes responsible for ECM synthesis, deposition, and remodeling. Fibrosis develops in response to a trigger or injury and can occur in nearly all organs of the body. Thus, fibrosis leads to severe pathological conditions that disrupt organ architecture and cause loss of function. It has been estimated that severe fibrotic disorders are responsible for up to one-third of deaths worldwide. Although intensive research on the development of new strategies for fibrosis treatment has been carried out, therapeutic approaches remain limited. Since stem cells, especially mesenchymal stem cells (MSCs), show remarkable self-renewal, differentiation, and immunomodulatory capacity, they have been intensively tested in preclinical studies and clinical trials as a potential tool to slow down the progression of fibrosis and improve the quality of life of patients with fibrotic disorders. In this review, we summarize in vitro studies, preclinical studies performed on animal models of human fibrotic diseases, and recent clinical trials on the efficacy of allogeneic and autologous stem cell applications in severe types of fibrosis that develop in lungs, liver, heart, kidney, uterus, and skin. Although the results of the studies seem to be encouraging, there are many aspects of cell-based therapy, including the cell source, dose, administration route and frequency, timing of delivery, and long-term safety, that remain open areas for future investigation. We also discuss the contemporary status, challenges, and future perspectives of stem cell transplantation for therapeutic options in fibrotic diseases as well as we present recent patents for stem cell-based therapies in organ fibrosis.

Translational insights into stem cell preconditioning: From molecular mechanisms to preclinical applications

Cell-based therapy (CBT) is a revolutionary approach for curing a variety of degenerative diseases. Stem cell-based regenerative medicine is a novel strategy for treating tissue damages regarding stem cells unique properties such as differentiation potential, paracrine impacts, and self-renewal ability. However, the current cell-based treatments encounter considerable challenges to be translated into clinical practice, including low cell survival, migration, and differentiation rate of transplanted stem cells. The poor stem cell therapy outcomes mainly originate from the unfavorable condition of damaged tissues for transplanted stem cells. The promising method of preconditioning improves cell resistance against the host environment's stress by imposing certain conditions similar to the harsh microenvironment of the damaged tissues on the transplanted stem cells. Various pharmacological, biological, and physical inducers are able to establish preconditioning. In addition to their known pharmacological effects on tissues and cells, these preconditioning agents improve cell biological aspects such as cell survival, proliferation, differentiation, migration, immunomodulation, paracrine impacts, and angiogenesis. This review focuses on different protocols and inducers of preconditioning along with underlying molecular mechanisms of their effects on stem cell behavior. Moreover, preclinical applications of preconditioned stem cells in various damaged organs such as heart, lung, brain, bone, cartilage, liver, and kidney are discussed with prospects of their translation into the clinic.

Anti-apoptotic effect of Nisin as a prebiotic on human mesenchymal stem cells in harsh condition

Mesenchymal stem cells (MSCs) are progenitor cells of connective tissue with the ability of proliferation, self-renewal, and multilineage differentiation that make it a promising source with an enormous potential to be utilized for tissue repairing and vehicles of cell-based gene therapy. The low survival rate of MSCs following transplantation is their drawback. Preconditioning with some factors is a novel and effective strategy, improving the survival of the cells by protecting them from harmful conditions and result in the good recovery of injured tissues. Nisin is a prebiotic with antimicrobial activity. This manuscript aimed to evaluate the effect of Nisin preconditioning of MSCs on in vitro cell viability. MSCs were cultured and preconditioned with Nisin in different concentrations. Then, they are separately exposed to H₂O₂ and serum deprivation. Cell survival and cell apoptosis were evaluated by MTT assay and Real-time PCR, respectively. Furthermore, Annexin-PI staining and caspase activity was performed to visualize apoptotic cells. MSC-Nisin viability and proliferation significantly increased when exposed to H₂O₂ and serum deprivation, compared to that of MSCs. About 250 and 500 IU/mL of Nisin donate a significant anti-apoptotic impact to MSCs. Our data suggest that preconditioning with Nisin has been improved cell viability and the anti-apoptotic capacity of MSCs. However, the mechanism related to the protective properties of preconditioning and using this strategy in stem cell therapy requires more research.

The Potential Properties of Natural Compounds in Cardiac Stem Cell Activation: Their Role in Myocardial Regeneration

Cardiovascular diseases (CVDs), which include congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, and many other cardiac disorders, cause about 30% of deaths globally; representing one of the main health problems worldwide. Among CVDs, ischemic heart diseases (IHDs) are one of the major causes of morbidity and mortality in the world. The onset of IHDs is essentially due to an unbalance between the metabolic demands of the myocardium and its supply of oxygen and nutrients, coupled with a low regenerative capacity of the heart, which leads to great cardiomyocyte (CM) loss; promoting heart failure (HF) and myocardial infarction (MI). To date, the first strategy recommended to avoid IHDs is prevention in order to reduce the underlying risk factors. In the management of IHDs, traditional therapeutic options are widely used to improve symptoms, attenuate adverse cardiac remodeling, and reduce early mortality rate. However, there are no available treatments that aim to improve cardiac performance by replacing the irreversible damaged cardiomyocytes (CMs). Currently, heart transplantation is the only treatment being carried out for irreversibly damaged CMs. Hence, the discovery of new therapeutic options seems to be necessary. Interestingly, recent experimental evidence suggests that regenerative stem cell medicine could be a useful therapeutic approach to counteract cardiac damage and promote tissue regeneration. To this end, researchers are tasked with answering one main question: how can myocardial regeneration be stimulated? In this regard, natural compounds from plant extracts seem to play a particularly promising role. The present review will summarize the recent advances in our knowledge of stem cell therapy in the management of CVDs; focusing on the main properties and potential mechanisms of natural compounds in stimulating and activating stem cells for myocardial regeneration.

Challenges and Limitations of Strategies to Promote Therapeutic Potential of Human Mesenchymal Stem Cells for Cell-Based Cardiac Repair

Mesenchymal stem cells (MSCs) represent a population of adult stem cells residing in many tissues, mainly bone marrow, adipose tissue, and umbilical cord. Due to the safety and availability of standard procedures and protocols for isolation, culturing, and characterization of these cells, MSCs have emerged as one of the most promising sources for cell-based cardiac regenerative therapy. Once transplanted into a damaged heart, MSCs release paracrine factors that nurture the injured area, prevent further adverse cardiac remodeling, and mediate tissue repair along with vasculature. Numerous preclinical studies applying MSCs have provided significant benefits following myocardial infarction. Despite promising results from preclinical studies using animal models, MSCs are not up to the mark for human clinical trials. As a result, various approaches have been considered to promote the therapeutic potency of MSCs, such as genetic engineering, physical treatments, growth factor, and pharmacological agents. Each strategy has targeted one or multi-potentials of MSCs. In this review, we will describe diverse approaches that have been developed to promote the therapeutic potential of MSCs for cardiac regenerative therapy. Particularly, we will discuss major characteristics of individual strategy to enhance therapeutic efficacy of MSCs including scientific principles, advantages, limitations, and improving factors. This article also will briefly introduce recent novel approaches that MSCs enhanced therapeutic potentials of other cells for cardiac repair.

Stem Cell Metabolism: Powering Cell-Based Therapeutics

Cell-based therapeutics for cardiac repair have been extensively used during the last decade. Preclinical studies have demonstrated the effectiveness of adoptively transferred stem cells for enhancement of cardiac function. Nevertheless, several cell-based clinical trials have provided largely underwhelming outcomes. A major limitation is the lack of survival in the harsh cardiac milieu as only less than 1% donated cells survive. Recent efforts have focused on enhancing cell-based therapeutics and understanding the biology of stem cells and their response to environmental changes. Stem cell metabolism has recently emerged as a critical determinant of cellular processes and is uniquely adapted to support proliferation, stemness, and commitment. Metabolic signaling pathways are remarkably sensitive to different environmental signals with a profound effect on cell survival after adoptive transfer. Stem cells mainly generate energy through glycolysis while maintaining low oxidative phosphorylation (OxPhos), providing metabolites for biosynthesis of macromolecules. During commitment, there is a shift in cellular metabolism, which alters cell function. Reprogramming stem cell metabolism may represent an attractive strategy to enhance stem cell therapy for cardiac repair. This review summarizes the current literature on how metabolism drives stem cell function and how this knowledge can be applied to improve cell-based therapeutics for cardiac repair.

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.

Manipulated Mesenchymal Stem Cells Applications in Neurodegenerative Diseases

Mesenchymal stem cells (MSCs) are multipotent stem cells that have multilinear differentiation and self-renewal abilities. These cells are immune-privileged as they express no or low level of class-II major histocompatibility complex (MHC-II) and other costimulatory molecules. Having neuroprotective and regenerative properties, MSCs can be used to ameliorate several intractable neurodegenerative disorders by affecting both innate and adaptive immune systems. Several manipulations like pretreating MSCs with different conditions or agents, and using molecules derived from MSCs or genetically manipulating them, are the common and practical ways that can be used to strengthen MSCs survival and potency. Improved MSCs can have significantly enhanced impacts on diseases compared to MSCs not manipulated. In this review, we describe some of the most important manipulations that have been exerted on MSCs to improve their therapeutic functions and their applications in ameliorating three prevalent neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and Huntington's disease.

Protective effect of morin on doxorubicin-induced hepatorenal toxicity in rats

Although Doxorubicin (DOX) is a widespread drug used in the treatment of cancer, its clinical use is restricted due to its common side effects. In addition, administrating DOX with an antioxidant has recently become a new strategy in preventing the side effects of DOX. The protective effects of morin, a natural flavonoid, against DOX-induced liver and kidney damage in rats were investigated biochemically, immunohistochemically and histopathologically in this study. The experimental procedure was planned as 10 days, and 5 groups consisting of seven rats were formed. Morin was given orally to rats at a dose of 50 and 100 mg/kg for 10 days and DOX was given a single dose of 40 mg/kg intraperitoneally on day 8. In order to determine the protective effect of morin against oxidative stress caused by DOX, reduced glutathione (GSH) and malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activities were measured in liver and kidney tissues. Liver and kidney tissue damage were determined both histopathologically and by serum alanine transaminase (ALT), aspartate transaminase (AST), urea and creatinine analysis. In order to determine the effect of DOX-induced inflammation and against the effect of morin, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nuclear factor kappa B (NF-κB) levels were determined in both tissues. Liver and kidney B-cell lymphoma-2 (Bcl-2) levels were determined biochemically. In addition, Bax expression in liver tissue and aquaporin-2 (AQP-2) and nephrin expression in renal tissue were determined immunohistochemically. It was determined that oxidative damage caused by DOX decreased and improvement of liver and kidney function markers were observed in the groups that were treated with morin. In addition, pre-treatment of morin showed a regulatory effect on TNF-α, IL-1β and NF-κB levels. It prevented the increase in DOX-induced Bax expression and decrease in Bcl-2 level, AQP-2 and nephrin expression. Histopathological examination revealed that it prevented tissue damage in liver and kidney tissues.

Role of interleukin-7 in fusion of rat bone marrow mesenchymal stem cells with cardiomyocytes in vitro and improvement of cardiac function in vivo

AIMS

Mesenchymal stem cells (MSCs) hold significant promise as potential therapeutic candidates following cardiac injury. However, to ensure survival of transplanted cells in ischemic environment, it is beneficial to precondition them with growth factors that play important role in cell survival and proliferation. Aim of this study is to use interleukin-7 (IL-7), a cell survival growth factor, to enhance the potential of rat bone marrow MSCs in terms of cell fusion in vitro and cardiac function in vivo.

METHODS

Mesenchymal stem cells were transfected with IL-7 gene through retroviral vector. Normal and transfected MSCs were co-cultured with neonatal cardiomyocytes (CMs) and cell fusion was analyzed by flow cytometry and fluorescence microscopy. These MSCs were also transplanted in rat model of myocardial infarction (MI) and changes at tissue level and cardiac function were assessed by histological analysis and echocardiography, respectively.

RESULTS

Co-culture of IL-7 transfected MSCs and CMs showed significantly higher (P < 0.01) number of fused cells as compared to normal MSCs. Histological analysis of hearts transplanted with IL-7 transfected MSCs showed significant reduction (P < 0.001) in infarct size and better preservation (P < 0.001) of left ventricular wall thickness as compared to normal MSCs. Presence of cardiac-specific proteins, α-actinin, and troponin-T showed that the transplanted MSCs were differentiated into cardiomyocytes. Echocardiographic recordings of the experimental group transplanted with transfected MSCs showed significant increase in the ejection fraction and fractional shortening (P < 0.01), and decrease in diastolic and systolic left ventricular internal diameters (P < 0.001) and end systolic and diastolic volumes (P < 0.01 and P < 0.001, respectively).

CONCLUSION

Interleukin-7 is able to enhance the fusogenic properties of MSCs and improve cardiac function. This improvement may be attributed to the supportive action of IL-7 on cell proliferation and cell survival contributing to the regeneration of damaged myocardium.

The Challenges of Stem Cell Therapy in Myocardial Infarction and Heart Failure and the Potential Strategies to Improve the Outcomes

Cardiovascular disease remains the single highest global cause of death and a significant financial burden on the healthcare system. Despite the advances in medical treatments, the prevalence and mortality for heart failure remain unacceptably high. New approaches are urgently needed to reduce this burden and improve patient outcomes and quality of life. One such promising approach is stem cell therapy, including embryonic stem cells, bone marrow derived stem cells, induced pluripotent stem cells and mesenchymal stem cells. However, the cardiac microenvironment following myocardial infarction poses huge challenges with inflammation, adequate retention, engraftment and functional incorporation all crucial concerns. The lack of cardiac regeneration, cell viability and functional improvement has hindered the success of stem cell therapy in clinical settings. The use of biomaterial scaffolds in conjunction with stem cells has recently been shown to enhance the outcome of stem cell therapy for heart failure and myocardial infarction. This review outlines some of the current challenges in the treatment of heart failure and acute myocardial infarction through improving stem cell therapeutic strategies, as well as the prospect of suitable biomaterial scaffolds to enhance their efficacy and improve patient clinical outcomes.

Anti-inflammatory effects of human embryonic stem cell-derived mesenchymal stem cells secretome preconditioned with diazoxide, trimetazidine and MG-132 on LPS-induced systemic inflammation mouse model

Systemic inflammatory response syndrome is a complex pathophysiologic and immunologic response to an insult. Sepsis is a life-threatening condition happening when the body's response to infection causes injury to its own tissues and organs. Stem cell therapy is a new approach to modulate immune responses. Mesenchymal stem cells (MSCs) establish a regenerative niche by secreting secretome and modulating immune responses. MSC secretome can be leveraged for therapeutic applications if production of secretary molecules were optimized. Pharmacological preconditioning using small molecules can increase survival of MSCs after transplantation. The aim of this study was to investigate the effect of secretome of human embryonic-derived mesenchymal stem cells (hESC-MSCs) preconditioned with MG-132,Trimetazidine (TMZ) and Diazoxide (DZ) on immunomodulatory efficiency of these cells in Lipo polysaccharide (LPS) challenged mice models. Mice were injected intraperitoneally with LPS and groups of animals were intraperitoneally given 1 ml 30× secretome 6 h after LPS injection. Serum levels of biochemical parameters were then measured by an auto analyser and serum inflammatory cytokine levels were analysed using commercially available RayBio Mouse Inflammation Antibody Array. Ultimately, histopathology and survival studies were conducted. The results showed that TMZ and DZ-conditioned medium significantly increasing the survival and improvement of histopathological score. We found that MG-132-conditioned medium failed to show significant outcomes. This study demonstrated that human MSC secretome has the potential to control inflammation.

Aspirin inhibits growth and enhances cardiomyocyte differentiation of bone marrow mesenchymal stem cells

This study aimed to examine the effects of aspirin on the growth and cardiomyocyte differentiation grade of bone marrow mesenchymal stem cells (BMMSCs). BMMSCs were divided into five differentiation groups with different concentrations of aspirin (0 mM, 0.5 mM, 1 mM, 2 mM, or 5 mM), and a undifferentiated control group. Cell growth was measured by cell proliferation, apoptosis assays and DNA cycle analysis. The differentiation grade of BMMSC-derived cardiomyocyte-like cells was examined by measuring the levels of cardiac-specific proteins with cyto-immunofluorescence staining, flow cytometry, and Western blotting. Electrophysiological analyses were performed by patch-clamp experiments and calcium transients were measured by a laser scanning confocal microscope. Cell proliferation decreased as the concentration of aspirin increased. Cell apoptosis increased with increasing aspirin concentration. DNA replication was inhibited in the high dose-aspirin group compared to the low dose- or non-aspirin groups. The number of α-myosin heavy chain (α-MHC) and cardiac troponin I (cTnI) positive cells, cardiac troponin T (cTnT) and connexin 43 (Cx43) positive rates, expression levels of Cx43, Nkx2.5, GATA4 and β1 adrenoceptor increased with increasing aspirin concentration. No sarcomeric cross-striations, spontaneous or induced beating activity or action potentials was observed in each group. Calcium transients were measured in small number cells in 2 mM aspirin group, but the features are atypical. Consequently, aspirin inhibits proliferation and survival of BMMSCs and enhances cardiomyocyte differentiation of BMMSCs.

The effect of hydroxy safflower yellow A on coronary heart disease through Bcl-2/Bax and PPAR-γ

The aim of the present study was to investigate the effect of hydroxy safflower yellow A (HSYA) on coronary heart disease through assessing the expression of B-cell lymphoma 2 (Bcl-2)/Bcl-2-like protein 4 (Bax) and peroxisome proliferator-activated receptor (PPAR)-γ. Coronary heart disease was induced in male Bama miniature swines via thoracoscope to serve as an animal model. Coronary heart disease swine were lavaged with 20 or 40 mg/kg HSYA. The mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were detected using reverse transcription-quantitative polymerase chain reaction. The protein expression of Bcl-2, Bax, PPAR-γ, phosphorylation of Janus kinase (JAK)2 and phosphorylation of signal transducer and activator of transcription (STAT)3 were detected using western blot analysis. Treatment with HSYA significantly suppressed the mRNA levels of IL-1β (P<0.01), IL-6 (P<0.01), TNF-α (P<0.01), COX-2 (P<0.01) and iNOS (P<0.01), and significantly increased IL-10 mRNA level in the coronary heart disease model (P<0.01). Furthermore, HSYA treatment significantly decreased the Bcl-2/Bax ratio (P<0.01) in the coronary heart disease model group, and enhanced the phosphorylation of JAK2/STAT3 pathway (P<0.01). However, HSYA had no significant effect on the expression of PPAR-γ protein. The results of the present study suggest that HSYA is able to weaken coronary heart disease via inflammation, Bcl-2/Bax and the PPAR-γ signaling pathway.

Challenges and Strategies for Improving the Regenerative Effects of Mesenchymal Stromal Cell-Based Therapies

Cell-based therapies have the potential to revolutionize current treatments for diseases with high prevalence and related economic and social burden. Unfortunately, clinical trials have made only modest improvements in restoring normal function to degenerating tissues. This limitation is due, at least in part, to the death of transplanted cells within a few hours after transplant due to a combination of mechanical, cellular, and host factors. In particular, mechanical stress during implantation, extracellular matrix loss upon delivery, nutrient and oxygen deprivation at the recipient site, and host inflammatory response are detrimental factors limiting long-term transplanted cell survival. The beneficial effect of cell therapy for regenerative medicine ultimately depends on the number of administered cells reaching the target tissue, their viability, and their promotion of tissue regeneration. Therefore, strategies aiming at improving viable cell engraftment are crucial for regenerative medicine. Here we review the major factors that hamper successful cell engraftment and the strategies that have been studied to enhance the beneficial effects of cell therapy. Moreover, we provide a perspective on whether mesenchymal stromal cell-derived extracellular vesicle delivery, as a cell-free regenerative approach, may circumvent current cell therapy limitations.

Sub-physiological oxygen levels optimal for growth and survival of human atrial cardiac stem cells

Cardiac stem cells reside in niches where the oxygen levels are close to 3%. For cytotherapy, cells are conventionally expanded in ambient oxygen (21% O₂) which represents hyperoxia compared to the oxygen tension of niches. Cardiosphere-derived cells (CDCs) are then transplanted to host tissue with lower-O₂ levels. The high-O₂ gradient can reduce the efficacy of cultured cells. Based on the assumption that minimizing injury due to O₂ gradients will enhance the yield of functionally efficient cells, CDCs were cultured in 3% O₂ and compared with cells maintained in ambient O₂. CDCs were isolated from human right atrial explants and expanded in parallel in 21 and 3% oxygen and compared with regard to survival, proliferation, and retention of stemness. Increased cell viability even in the tenth passage and enhanced cardiosphere formation was observed in cells expanded in 3% O₂. The cell yield from seven passages was fourfold higher for cells cultured in 3% O₂. Preservation of stemness in hypoxic environment was evident from the proportion of c-kit-positive cells and reduced myogenic differentiation. Hypoxia promoted angiogenesis and reduced the tendency to differentiate to noncardiac lineages (adipocytes and osteocytes). Mimicking the microenvironment at transplantation, when shifted to 5% O₂, viability and proliferation rate were significantly higher for CDCs expanded in 3% O₂. Expansion of CDCs, from atria in sub-physiological oxygen, helps in obtaining a higher yield of healthy cells with better preservation of stem cell characteristics. The cells so cultured are expected to improve engraftment and facilitate myocardial regeneration.

Proteomics-based network analysis characterizes biological processes and pathways activated by preconditioned mesenchymal stem cells in cardiac repair mechanisms

BACKGROUND

We have demonstrated that intramyocardial delivery of human mesenchymal stem cells preconditioned with a hyaluronan mixed ester of butyric and retinoic acid (MSCp⁺) is more effective in preventing the decay of regional myocardial contractility in a swine model of myocardial infarction (MI). However, the understanding of the role of MSCp⁺ in proteomic remodeling of cardiac infarcted tissue is not complete. We therefore sought to perform a comprehensive analysis of the proteome of infarct remote (RZ) and border zone (BZ) of pigs treated with MSCp⁺ or unconditioned stem cells.

METHODS

Heart tissues were analyzed by MudPIT and differentially expressed proteins were selected by a label-free approach based on spectral counting. Protein profiles were evaluated by using PPI networks and their topological analysis.

RESULTS

The proteomic remodeling was largely prevented in MSCp⁺ group. Extracellular proteins involved in fibrosis were down-regulated, while energetic pathways were globally up-regulated. Cardioprotectant pathways involved in the production of keto acid metabolites were also activated. Additionally, we found that new hub proteins support the cardioprotective phenotype characterizing the left ventricular BZ treated with MSCp⁺. In fact, the up-regulation of angiogenic proteins NCL and RAC1 can be explained by the increase of capillary density induced by MSCp⁺.

CONCLUSIONS

Our results show that angiogenic pathways appear to be uniquely positioned to integrate signaling with energetic pathways involving cardiac repair.

GENERAL SIGNIFICANCE

Our findings prompt the use of proteomics-based network analysis to optimize new approaches preventing the post-ischemic proteomic remodeling that may underlie the limited self-repair ability of adult heart.

Vitamin E protects rat mesenchymal stem cells against hydrogen peroxide-induced oxidative stress in vitro and improves their therapeutic potential in surgically-induced rat model of osteoarthritis

OBJECTIVE

Oxidative stress is a major obstacle against cartilage repair in osteoarthritis (OA). Anti-oxidant agents can play a vital role in addressing this issue. We evaluated the effect of Vitamin E preconditioning in improving the potential of mesenchymal stem cells (MSCs) to confer resistance against oxidative stress prevailing during OA.

METHODS

Vitamin E pretreated MSCs were exposed to oxidative stress in vitro by hydrogen peroxide (H₂O₂) and also implanted in surgically-induced rat model of OA. Analysis was done in terms of cell proliferation, apoptosis, cytotoxicity, chondrogenesis and repair of cartilage tissue.

RESULTS

Vitamin E pretreatment enabled MSCs to counteract H₂O₂-induced oxidative stress in vitro. Proliferative markers, proliferating cell nuclear antigen (PCNA) and Ki67 were up-regulated, along with the increase in the viability of MSCs. Expression of transforming growth factor-beta (TGFβ) was also increased. Reduction of apoptosis, expression of vascular endothelial growth factor (VEGF) and caspase 3 (Casp3) genes, and lactate dehydrogenase (LDH) release were also observed. Transplantation of Vitamin E pretreated MSCs resulted in increased proteoglycan contents of cartilage matrix. Increased expression of chondrogenic markers, Aggrecan (Acan) and collagen type-II alpha (Col2a1) accompanied by decreased expression of collagen type-I alpha (Col1a1) resulted in increased differentiation index that signifies the formation of hyaline cartilage. Further, there was an increased expression of PCNA and TGFβ genes along with a decreased expression of Casp3 and VEGF genes with increased histological score.

CONCLUSION

Taken together results of this study demonstrated that Vitamin E pretreated MSCs have an improved ability to impede the progression of OA and thus increased potential to treat OA.

Optimizing stem cells for cardiac repair: Current status and new frontiers in regenerative cardiology

Cell therapy has the potential to improve healing of ischemic heart, repopulate injured myocardium and restore cardiac function. The tremendous hope and potential of stem cell therapy is well understood, yet recent trials involving cell therapy for cardiovascular diseases have yielded mixed results with inconsistent data thereby readdressing controversies and unresolved questions regarding stem cell efficacy for ischemic cardiac disease treatment. These controversies are believed to arise by the lack of uniformity of the clinical trial methodologies, uncertainty regarding the underlying reparative mechanisms of stem cells, questions concerning the most appropriate cell population to use, the proper delivery method and timing in relation to the moment of infarction, as well as the poor stem cell survival and engraftment especially in a diseased microenvironment which is collectively acknowledged as a major hindrance to any form of cell therapy. Indeed, the microenvironment of the failing heart exhibits pathological hypoxic, oxidative and inflammatory stressors impairing the survival of transplanted cells. Therefore, in order to observe any significant therapeutic benefit there is a need to increase resilience of stem cells to death in the transplant microenvironment while preserving or better yet improving their reparative functionality. Although stem cell differentiation into cardiomyocytes has been observed in some instance, the prevailing reparative benefits are afforded through paracrine mechanisms that promote angiogenesis, cell survival, transdifferentiate host cells and modulate immune responses. Therefore, to maximize their reparative functionality, ex vivo manipulation of stem cells through physical, genetic and pharmacological means have shown promise to enable cells to thrive in the post-ischemic transplant microenvironment. In the present work, we will overview the current status of stem cell therapy for ischemic heart disease, discuss the most recurring cell populations employed, the mechanisms by which stem cells deliver a therapeutic benefit and strategies that have been used to optimize and increase survival and functionality of stem cells including ex vivo preconditioning with drugs and a novel “pharmaco-optimizer” as well as genetic modifications.

Can the outcomes of mesenchymal stem cell-based therapy for myocardial infarction be improved? Providing weapons and armour to cells

Use of mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI) has been found to have infarct-limiting effects in numerous experimental and clinical studies. However, recent meta-analyses of randomized clinical trials on MSC-based MI therapy have highlighted the need for improving its efficacy. There are two principal approaches for increasing therapeutic effect of MSCs: (i) preventing massive MSC death in ischaemic tissue and (ii) increasing production of cardioreparative growth factors and cytokines with transplanted MSCs. In this review, we aim to integrate our current understanding of genetic approaches that are used for modification of MSCs to enable their improved survival, engraftment, integration, proliferation and differentiation in the ischaemic heart. Genetic modification of MSCs resulting in increased secretion of paracrine factors has also been discussed. In addition, data on MSC preconditioning with physical, chemical and pharmacological factors prior to transplantation are summarized. MSC seeding on three-dimensional polymeric scaffolds facilitates formation of both intercellular connections and contacts between cells and the extracellular matrix, thereby enhancing cell viability and function. Use of genetic and non-genetic approaches to modify MSC function holds great promise for regenerative therapy of myocardial ischaemic injury.

Stem cell-based therapy: Improving myocardial cell delivery

Stem cell-based therapies form an exciting new class of medicine that attempt to provide the body with the building blocks required for the reconstruction of damaged organs. However, delivering cells to the correct location, while preserving their integrity and functional properties, is a complex undertaking. These challenges have led to the development of a highly dynamic interdisciplinary research field, wherein medical, biological, and chemical sciences have collaborated to develop strategies to overcome the physiological barriers imposed on the cellular therapeutics. In this respect, improving the acute retention and subsequent survival of stem cells is key to effectively increase the effect of the therapy, while proper tissue integration is imperative for stem cells to functionally replace lost cells in damaged organs. In this review, we will use the heart as an example to highlight the current knowledge of therapeutic stem cell utilization, the existing pitfalls and limitations, and the approaches that have been developed to overcome them.

Quiescence Preconditioned Human Multipotent Stromal Cells Adopt a Metabolic Profile Favorable for Enhanced Survival under Ischemia

A major impediment to the development of therapies with mesenchymal stem cells/multipotent stromal cells (MSC) is the poor survival and engraftment of MSCs at the site of injury. We hypothesized that lowering the energetic demand of MSCs by driving them into a quiescent state would enhance their survival under ischemic conditions. Human MSCs (hMSCs) were induced into quiescence by serum deprivation (SD) for 48 hours. Such preconditioned cells (SD-hMSCs) exhibited reduced nucleotide and protein syntheses compared to unpreconditioned hMSCs. SD-hMSCs sustained their viability and their ATP levels upon exposure to severe, continuous, near-anoxia (0.1% O₂ ) and total glucose depletion for up to 14 consecutive days in vitro, as they maintained their hMSC multipotential capabilities upon reperfusion. Most importantly, SD-hMSCs showed enhanced viability in vivo for the first week postimplantation in mice. Quiescence preconditioning modified the energy-metabolic profile of hMSCs: it suppressed energy-sensing mTOR signaling, stimulated autophagy, promoted a shift in bioenergetic metabolism from oxidative phosphorylation to glycolysis and upregulated the expression of gluconeogenic enzymes, such as PEPCK. Since the presence of pyruvate in cell culture media was critical for SD-hMSC survival under ischemic conditions, we speculate that these cells may utilize some steps of gluconeogenesis to overcome metabolic stress. These findings support that SD preconditioning causes a protective metabolic adaptation that might be taken advantage of to improve hMSC survival in ischemic environments. Stem Cells 2017;35:181-196.

Adipose-derived mesenchymal stem cells from patients with atherosclerotic renovascular disease have increased DNA damage and reduced angiogenesis that can be modified by hypoxia

BACKGROUND

Adipose-derived MSC (AMSCs) possess angiogenic and immunomodulatory properties that may modulate kidney regeneration. Whether these properties are retained in older patients with atherosclerotic vascular disease is poorly understood. Hypoxic conditions are known to modify properties and growth characteristics of AMSCs. We tested the hypothesis that AMSCs from older patients with atherosclerotic renovascular disease (RVD) differ from normal kidney donors, and whether hypoxia changes their functional and molecular properties to promote angiogenesis.

METHODS

AMSCs from 11 patients with RVD (mean age =74.5 years) and 10 healthy kidney donors (mean age = 51.2 years) were cultured under normoxia (20 % O2) and hypoxia (1 % O2) for 3-4 days until they reached 80 % confluency. We analyzed expression of genes and microRNAs using RNA sequencing and real-time quantitative rt-PCR. Protein expression of selected angiogenic factors (VEGF, IGF, HGF and EGF) were quantified in conditioned media using ELISAs. Apoptosis was tested using Annexin IV staining.

RESULTS

Normoxic AMSC from RVD patients grew normally, but exhibited increased DNA damage and reduced migration. VEGF protein secretion was significantly lower in the RVD AMSCs (0.08 vs 2.4 ng/mL/ cell, p <0.05) while HGF was higher. Both trends were reversed during growth under hypoxic conditions. Hypoxia upregulated pro-angiogenic mRNAs expression in AMSCs (VEGF, FGF, STC and ANGPTL4), and downregulated expression of many miRNAs (e.g., miR-15a, miR-16, miR-93, miR-424, 126, 132, 221) except miR-210.

CONCLUSIONS

Thus, although AMSC from patients with RVD had increased DNA damage and reduced migration, hypoxia stimulated pro-angiogenic responses via increased expression of angiogenic genes, VEGF secretion and induction of the hypoxia-inducible miR-210, while downregulating angiogenesis-related miRNAs.

Therapeutic Strategies for Oxidative Stress-Related Cardiovascular Diseases: Removal of Excess Reactive Oxygen Species in Adult Stem Cells

Accumulating evidence indicates that acute and chronic uncontrolled overproduction of oxidative stress-related factors including reactive oxygen species (ROS) causes cardiovascular diseases (CVDs), atherosclerosis, and diabetes. Moreover ROS mediate various signaling pathways underlying vascular inflammation in ischemic tissues. With respect to stem cell-based therapy, several studies clearly indicate that modulating antioxidant production at cellular levels enhances stem/progenitor cell functionalities, including proliferation, long-term survival in ischemic tissues, and complete differentiation of transplanted cells into mature vascular cells. Recently emerging therapeutic strategies involving adult stem cells, including endothelial progenitor cells (EPCs), for treating ischemic CVDs have highlighted the need to control intracellular ROS production, because it critically affects the replicative senescence of ex vivo expanded therapeutic cells. Better understanding of the complexity of cellular ROS in stem cell biology might improve cell survival in ischemic tissues and enhance the regenerative potentials of transplanted stem/progenitor cells. In this review, we will discuss the nature and sources of ROS, drug-based therapeutic strategies for scavenging ROS, and EPC based therapeutic strategies for treating oxidative stress-related CVDs. Furthermore, we will discuss whether primed EPCs pretreated with natural ROS-scavenging compounds are crucial and promising therapeutic strategies for vascular repair.

Preconditioning of mesenchymal stem cells with 2,4-dinitrophenol improves cardiac function in infarcted rats

AIMS

The aim of this study is to determine if preconditioning of bone marrow derived mesenchymal stem cells (MSCs) with 2,4-dinitrophenol (DNP) improves survival of transplanted stem cells in a rat model of myocardial infarction (MI), and to asses if this strategy has measurable impact on cardiac function.

MAIN METHODS

MSCs were preconditioned with DNP. In vitro cell adhesion assay and qRT-PCR were performed to analyze the expression of genes involved in cardiomyogenesis, cell adhesion and angiogenesis. MI was produced by occlusion of left anterior descending coronary artery. One million cells were transplanted by intramyocardial injection into the infarcted myocardium. Echocardiography was performed after two and four weeks of cellular transplantation. Hearts were harvested after four weeks and processed for histological analysis.

KEY FINDINGS

DNP treated MSCs adhered to the surface more (p<0.001) as compared to the normal MSCs. Gene expression levels were significantly upregulated in case of DNP treatment. The number of viable MSCs was more (p<0.001) in animals that received DNP treated MSCs, leading to significant improvement in cardiac function. Histological analysis revealed significant reduction in scar formation (p<0.001), maintenance of left ventricular wall thickness (p<0.001), and increased angiogenesis (p<0.01).

SIGNIFICANCE

The study evidenced for the first time that MSCs preconditioned with DNP improved cardiac function after transplantation. This can be attributed to improved survival, homing, adhesion, and cardiomyogenic and angiogenic differentiation of DNP treated MSCs in vivo.

Hypoxic Preconditioning Improves the Therapeutic Potential of Aging Bone Marrow Mesenchymal Stem Cells in Streptozotocin-Induced Type-1 Diabetic Mice

Insulin replacement is the current therapeutic option for type-1 diabetes. However, exogenous insulin cannot precisely represent the normal pattern of insulin secretion. Another therapeutic strategy is transplantation of pancreatic islets, but this is limited by immune rejection, intrinsic complications, and lack of donor availability. Stem cell therapy that results in the regeneration of insulin-producing cells represents an attractive choice. However, with advancing age, stem cells also undergo senescence, which leads to changes in the function of various cellular processes that result in a decrease in the regeneration potential of these aging stem cells. In this study, the effect of young and aging mesenchymal stem cells (MSCs) on the regeneration of pancreatic beta cells in streptozotocin (STZ)-induced type-1 diabetic mice was observed after hypoxic preconditioning. Hypoxia was chemically induced by 2, 4-dinitrophenol (DNP). Plasma insulin and glucose levels were measured at various time intervals, and pancreatic sections were analyzed histochemically. The effect of DNP was also analyzed on apoptosis of MSCs by flow cytometry and on gene expression of certain growth factors by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). We observed that hypoxic preconditioning caused changes in the gene expression levels of growth factors in both young and aging MSCs. Young MSCs showed significant regeneration potential compared with the aging cells in vivo. However, hypoxic preconditioning was able to improve the regeneration potential of aging MSCs. It is concluded from the present study that the regeneration potential of aging MSCs into pancreatic β-cells can be enhanced by hypoxic preconditioning, which causes changes in the gene expression of certain growth factors.

Mesenchymal Stem/Stromal Cells in Regenerative Medicine: Can Preconditioning Strategies Improve Therapeutic Efficacy?

Mesenchymal stem/stromal cells (MSCs) are becoming increasingly important for the development of cell therapeutics in regenerative medicine. Featuring immunomodulatory potential as well as secreting a variety of trophic factors, MSCs showed remarkable therapeutic effects in numerous preclinical disease models. However, sustainable translation of MSC therapies to the clinic is hampered by heterogeneity of MSCs and non-standardized in vitro culture technologies. Moreover, potent MSC therapeutics require MSCs with maximum regenerative capacity. There is growing evidence that in vitro preconditioning strategies of MSCs can optimize their therapeutic potential. In the following we will discuss achievements and challenges of the development of MSC therapies in regenerative medicine highlighting specific in vitro preconditioning strategies prior to cell transplantation to increase their therapeutic efficacy.

Rebuilding the Damaged Heart: Mesenchymal Stem Cells, Cell-Based Therapy, and Engineered Heart Tissue

Mesenchymal stem cells (MSCs) are broadly distributed cells that retain postnatal capacity for self-renewal and multilineage differentiation. MSCs evade immune detection, secrete an array of anti-inflammatory and anti-fibrotic mediators, and very importantly activate resident precursors. These properties form the basis for the strategy of clinical application of cell-based therapeutics for inflammatory and fibrotic conditions. In cardiovascular medicine, administration of autologous or allogeneic MSCs in patients with ischemic and nonischemic cardiomyopathy holds significant promise. Numerous preclinical studies of ischemic and nonischemic cardiomyopathy employing MSC-based therapy have demonstrated that the properties of reducing fibrosis, stimulating angiogenesis, and cardiomyogenesis have led to improvements in the structure and function of remodeled ventricles. Further attempts have been made to augment MSCs' effects through genetic modification and cell preconditioning. Progression of MSC therapy to early clinical trials has supported their role in improving cardiac structure and function, functional capacity, and patient quality of life. Emerging data have supported larger clinical trials that have been either completed or are currently underway. Mechanistically, MSC therapy is thought to benefit the heart by stimulating innate anti-fibrotic and regenerative responses. The mechanisms of action involve paracrine signaling, cell-cell interactions, and fusion with resident cells. Trans-differentiation of MSCs to bona fide cardiomyocytes and coronary vessels is also thought to occur, although at a nonphysiological level. Recently, MSC-based tissue engineering for cardiovascular disease has been examined with quite encouraging results. This review discusses MSCs from their basic biological characteristics to their role as a promising therapeutic strategy for clinical cardiovascular disease.

Mesenchymal stem cells in cardiac regeneration: a detailed progress report of the last 6 years (2010-2015)

Mesenchymal stem cells have been used for cardiovascular regenerative therapy for decades. These cells have been established as one of the potential therapeutic agents, following several tests in animal models and clinical trials. In the process, various sources of mesenchymal stem cells have been identified which help in cardiac regeneration by either revitalizing the cardiac stem cells or revascularizing the arteries and veins of the heart. Although mesenchymal cell therapy has achieved considerable admiration, some challenges still remain that need to be overcome in order to establish it as a successful technique. This in-depth review is an attempt to summarize the major sources of mesenchymal stem cells involved in myocardial regeneration, the significant mechanisms involved in the process with a focus on studies (human and animal) conducted in the last 6 years and the challenges that remain to be addressed.

Therapeutic potential of mesenchymal stem cells for pulmonary complications associated with preterm birth

Preterm infants frequently suffer from pulmonary complications resulting in significant morbidity and mortality. Physiological and structural lung immaturity impairs perinatal lung transition to air breathing resulting in respiratory distress. Mechanical ventilation and oxygen supplementation ensure sufficient oxygen supply but enhance inflammatory processes which might lead to the establishment of a chronic lung disease called bronchopulmonary dysplasia (BPD). Current therapeutic options to prevent or treat BPD are limited and have salient side effects, highlighting the need for new therapeutic approaches. Mesenchymal stem cells (MSCs) have demonstrated therapeutic potential in animal models of BPD. This review focuses on MSC-based therapeutic approaches to treat pulmonary complications and critically compares results obtained in BPD models. Thereby bottlenecks in the translational systems are identified that are preventing progress in combating BPD. Notably, current animal models closely resemble the so-called "old" BPD with profound inflammation and injury, whereas clinical improvements shifted disease pathology towards a "new" BPD in which arrest of lung maturation predominates. Future studies need to evaluate the utility of MSC-based therapies in animal models resembling the "new" BPD though promising in vitro evidence suggests that MSCs do possess the potential to stimulate lung maturation. Furthermore, we address the mode-of-action of MSC-based therapies with regard to lung development and inflammation/fibrosis. Their therapeutic efficacy is mainly attributed to an enhancement of regeneration and immunomodulation due to paracrine effects. In addition, we discuss current improvement strategies by genetic modifications or precondition of MSCs to enhance their therapeutic efficacy which could also prove beneficial for BPD therapies.

MicroRNA-133a engineered mesenchymal stem cells augment cardiac function and cell survival in the infarct heart

: Cardiovascular disease is the number 1 cause of morbidity and mortality in the United States. The most common manifestation of cardiovascular disease is myocardial infarction (MI), which can ultimately lead to congestive heart failure. Cell therapy (cardiomyoplasty) is a new potential therapeutic treatment alternative for the damaged heart. Recent preclinical and clinical studies have shown that mesenchymal stem cells (MSCs) are a promising cell type for cardiomyoplasty applications. However, a major limitation is the poor survival rate of transplanted stem cells in the infarcted heart. miR-133a is an abundantly expressed microRNA (miRNA) in the cardiac muscle and is downregulated in patients with MI. We hypothesized that reprogramming MSCs using miRNA mimics (double-stranded oligonucleotides) will improve survival of stem cells in the damaged heart. MSCs were transfected with miR-133a mimic and antagomirs, and the levels of miR-133a were measured by quantitative real-time polymerase chain reaction. Rat hearts were subjected to MI and MSCs transfected with miR-133a mimic or antagomir were implanted in the ischemic hearts. Four weeks after MI, cardiac function, cardiac fibrosis, miR-133a levels, and apoptosis-related genes (Apaf-1, Caspase-9, and Caspase-3) were measured in the heart. We found that transfecting MSCs with miR-133a mimic improves survival of MSCs as determined by the MTT assay. Similarly, transplantation of miR-133a mimic transfected MSCs in rat hearts subjected to MI led to a significant increase in cell engraftment, cardiac function, and decreased fibrosis when compared with MSCs only or MI groups. At the molecular level, quantitative real-time polymerase chain reaction data demonstrated a significant decrease in expression of the proapoptotic genes; Apaf-1, caspase-9, and caspase-3 in the miR-133a mimic transplanted group. Furthermore, luciferase reporter assay confirmed that miR-133a is a direct target for Apaf-1. Overall, bioengineering of stem cells through miRNAs manipulation could potentially improve the therapeutic outcome of patients undergoing stem cell transplantation for MI.

Empowering Adult Stem Cells for Myocardial Regeneration V2.0: Success in Small Steps

Much has changed since our survey of the landscape for myocardial regeneration powered by adult stem cells 4 years ago.(1) The intervening years since that first review has witnessed an explosive expansion of studies that advance both understanding and implementation of adult stem cells in promoting myocardial repair. Painstaking research from innumerable laboratories throughout the world is prying open doors that may lead to restoration of myocardial structure and function in the wake of pathological injury. This global effort has produced deeper mechanistic comprehension coupled with an evolving appreciation for the complexity of myocardial regeneration in the adult context. Undaunted by both known and (as yet) unknown challenges, pursuit of myocardial regenerative medicine mediated by adult stem cell therapy has gathered momentum fueled by tantalizing clues and visionary goals. This concise review takes a somewhat different perspective than our initial treatise, taking stock of the business sector that has become an integral part of the field while concurrently updating state of affairs in cutting edge research. Looking retrospectively at advancement over the years as all reviews eventually must, the fundamental lesson to be learned is best explained by Jonatan Mårtensson: "Success will never be a big step in the future. Success is a small step taken just now."

Human umbilical cord blood derived mesenchymal stem cells improve cardiac function in cTnT(R141W) transgenic mouse of dilated cardiomyopathy

Cell transplantation is a promising strategy in regenerative medicine. Beneficial effects of bone marrow mesenchymal stem cells (BM-MSCs) on heart disease have been widely reported. However, the MSCs in these studies have been mainly derived from autologous animals, and data on MSCs from human umbilical cord blood (UCB-MSCs) are still scarce. We investigated whether intramyocardial xenogeneic administration of UCB-MSCs is beneficial for preserving heart function in a cTnT(R141W) transgenic mouse of dilated cardiomyopathy (DCM). Cultured UCB-MSCs, which were identified by there morphology, differentiation and cell surface markers, were transplanted into cTnT(R141W) transgenic mice to examine apoptosis, fibrosis, vasculogenesis and the associated Akt pathway. Moreover, we measured the expression levels of VEGF and IGF-1, which are growth factors required for differentiation into cardiomyocytes, and are also involved in cardiac regeneration and improving heart function. One month after transplantation, MSCs significantly decreased chamber dilation and contractile dysfunction in the cTnT(R141W) mice. MSCs transplanted hearts showed a significant decrease in cardiac apoptosis and its regulation by the Akt pathway. Cardiac fibrosis and cytoplasmic vacuolisation were significantly attenuated in the MSCs group. Importantly, the levels of VEGF and IGF-1 were increased in the MSCs transplanted hearts. In vitro, the MSC-conditioned medium displayed anti-apoptotic activity in h9c2 cardiomyocytes subjected to hypoxia. These results further confirm the paracrine effects of MSCs. In conclusion, UCB-MSCs preserve cardiac function after intramyocardial transplantation in a DCM mouse, and this effect may be associated with reductions in cellular apoptosis, inflammation, hypertrophy and myocardial fibrosis; in addition to; up-regulation of Akt, VEGF and IGF-1; and enhanced angiogenesis.

Nicorandil enhances the efficacy of mesenchymal stem cell therapy in isoproterenol-induced heart failure in rats

Stem cell transplantation has emerged as a promising technique for regenerative medicine in cardiovascular therapeutics. However, the results have been less than optimal. The aim of the present study was to investigate whether nicorandil could offer an additional benefit over bone marrow-derived mesenchymal stem cell therapy in isoproterenol-induced myocardial damage and its progression to heart failure in rats. Isoproterenol was injected subcutaneously for 2 consecutive days at doses of 85 and 170 mg/kg/day, respectively. Nicorandil (3 mg/kg/day) was then given orally with or without a single intravenous bone marrow-derived mesenchymal stem cell administration. Electrocardiography and echocardiography were recorded 2 weeks after the beginning of treatment. Rats were then sacrificed and the ventricle was isolated for estimation of tumor necrosis factor-alpha, vascular endothelial growth factor and transforming growth factor-beta. Moreover, protein expressions of caspase-3, connexin-43 as well as endothelial and inducible nitric oxide synthases were evaluated. Finally, histological studies of myocardial fibrosis and blood vessel density were performed and cryosections were done for estimation cell homing. Combined nicorandil/bone marrow-derived mesenchymal stem cell therapy provided an additional improvement compared to cell therapy alone toward reducing isoproterenol-induced cardiac hypertrophy, fibrosis and inflammation. Notably, combined therapy induced significant increase in angiogenesis and cell homing and prevented isoproterenol-induced changes in contractility and apoptotic markers. In conclusion, combined nicorandil/bone marrow-derived mesenchymal stem cell therapy was superior to cell therapy alone toward preventing isoproterenol-induced heart failure in rats through creation of a supportive environment for mesenchymal stem cells.

Mesenchymal stem cells preconditioned with trimetazidine promote neovascularization of hearts under hypoxia/reoxygenation injury

BACKGROUND

Cell-based angiogenesis is a promising treatment for ischemic diseases; however, survival of implanted cells is impaired by the ischemic microenvironment. In this study, mesenchymal stem cells (MSCs) for cell transplantation were preconditioned with trimetazidine (TMZ). We hypothesized that TMZ enhances the survival rate of MSCs under hypoxic stimuli through up-regulation of HIF1-α.

METHODS AND RESULTS

Bone marrow-derived rat mesenchymal stem cells were preconditioned with 10 μM TMZ for 6 h. TMZ preconditioning of MSCs remarkably increased cell viability and the expression of HIF1-α and Bcl-2, when cells were under hypoxia/reoxygenation (H/R) stimuli. But the protective effects of TMZ were abolished after knocking down of HIF-1α. Three days after implantation of the cells into the peri-ischemic zone of rat myocardial ischemia-reperfusion (I/R) injury model, survival of the TMZ-preconditioned MSCs was high. Furthermore, capillary density and cardiac function were significantly better in the rats implanted with TMZ-preconditioned MSCs 28 days after cell injection.

CONCLUSIONS

TMZ preconditioning increased the survival rate of MSCs, through up-regulation of HIF1-α, thus contributing to neovascularization and improved cardiac function of rats subjected to myocardial I/R injury.

Effects of trimetazidine on the Akt/eNOS signaling pathway and oxidative stress in an in vivo rat model of renal ischemia-reperfusion

Renal ischemia reperfusion (I/R) injury, which occurs during renal surgery or transplantation, is the major cause of acute renal failure. Trimetazidine (TMZ), an anti-ischemic drug, protects kidney against the deleterious effects of I/R. However its protective mechanism remains unclear. The aim of this study is to examine the relevance of Akt, endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor-1α (HIF-1α) on TMZ induced protection of kidneys against I/R injury. Wistar rats were subjected to 60 min of warm renal ischemia followed by 120 min of reperfusion, or to intraperitoneal injection of TMZ (3 mg/kg) 30 min before ischemia. In sham operated group renal pedicles were only dissected. Compared to I/R, TMZ treatment decreased lactate dehydrogenase (845 ± 13 vs. 1028 ± 30 U/L). In addition, creatinine clearance and sodium reabsorption rates reached 105 ± 12 versus 31 ± 11 μL/min/g kidney weight and 95 ± 1 versus 68 ± 5%, respectively. Besides, we noted a decrease in malondialdehyde concentration (0.33 ± 0.01 vs. 0.59 ± 0.03 nmol/mg of protein) and an increase in glutathione concentration (2.6 ± 0.2 vs. 0.93 ± 0.16 µg GSH/mg of protein), glutathione peroxidase (95 ± 4 vs. 61 ± 3 µg GSH/min/mg of protein), and superoxide dismutase (25 ± 3 vs. 11 ± 2 U/mg of protein) and catalase (91 ± 12 vs. 38 ± 9 μmol/min/mg of protein) activities. Parallely, we noted a significant increase in p-Akt, eNOS, nitrite and nitrate (18 ± 2 vs. 8 ± 0.1 pomL/mg of protein), HIF-1α (333 ± 48 vs. 177 ± 14 µg/mg of protein) and heme oxygenase-1 (HO-1) levels regarding I/R. TMZ treatment improves renal tolerance to warm I/R. Such protection implicates an activation of Akt/eNOS signaling pathway, HIF-1α stabilization and HO-1 activation.

Use of mesenchymal stem cells for therapy of cardiac disease

Despite substantial clinical advances over the past 65 years, cardiovascular disease remains the leading cause of death in America. The past 15 years has witnessed major basic and translational interest in the use of stem and precursor cells as a therapeutic agent for chronically injured organs. Among the cell types under investigation, adult mesenchymal stem cells are widely studied, and in early stage, clinical studies show promise for repair and regeneration of cardiac tissues. The ability of mesenchymal stem cells to differentiate into mesoderm- and nonmesoderm-derived tissues, their immunomodulatory effects, their availability, and their key role in maintaining and replenishing endogenous stem cell niches have rendered them one of the most heavily investigated and clinically tested type of stem cell. Accumulating data from preclinical and early phase clinical trials document their safety when delivered as either autologous or allogeneic forms in a range of cardiovascular diseases, but also importantly define parameters of clinical efficacy that justify further investigation in larger clinical trials. Here, we review the biology of mesenchymal stem cells, their interaction with endogenous molecular and cellular pathways, and their modulation of immune responses. Additionally, we discuss factors that enhance their proliferative and regenerative ability and factors that may hinder their effectiveness in the clinical setting.