Cellular Therapeutics for Heart Failure: Focus on Mesenchymal Stem Cells

Control of the post-infarct immune microenvironment through biotherapeutic and biomaterial-based approaches

Ischemic heart failure (IHF) is a leading cause of morbidity and mortality worldwide, for which heart transplantation remains the only definitive treatment. IHF manifests from myocardial infarction (MI) that initiates tissue remodeling processes, mediated by mechanical changes in the tissue (loss of contractility, softening of the myocardium) that are interdependent with cellular mechanisms (cardiomyocyte death, inflammatory response). The early remodeling phase is characterized by robust inflammation that is necessary for tissue debridement and the initiation of repair processes. While later transition toward an immunoregenerative function is desirable, functional reorientation from an inflammatory to reparatory environment is often lacking, trapping the heart in a chronically inflamed state that perpetuates cardiomyocyte death, ventricular dilatation, excess fibrosis, and progressive IHF. Therapies can redirect the immune microenvironment, including biotherapeutic and biomaterial-based approaches. In this review, we outline these existing approaches, with a particular focus on the immunomodulatory effects of therapeutics (small molecule drugs, biomolecules, and cell or cell-derived products). Cardioprotective strategies, often focusing on immunosuppression, have shown promise in pre-clinical and clinical trials. However, immunoregenerative therapies are emerging that often benefit from exacerbating early inflammation. Biomaterials can be used to enhance these therapies as a result of their intrinsic immunomodulatory properties, parallel mechanisms of action (e.g., mechanical restraint), or by enabling cell or tissue-targeted delivery. We further discuss translatability and the continued progress of technologies and procedures that contribute to the bench-to-bedside development of these critically needed treatments.

Calycosin pretreatment enhanced the therapeutic efficacy of mesenchymal stem cells to alleviate unilateral ureteral obstruction-induced renal fibrosis by inhibiting necroptosis

Bone marrow-derived mesenchymal stem cells (MSCs) show antifibrotic activity in various chronic kidney diseases. Here, we aimed to investigate whether Calycosin (CA), a phytoestrogen, could enhance the antifibrotic activity of MSCs in primary tubular epithelial cells (PTECs) induced by TGF-β1 and in a mouse model of unilateral ureteral obstruction (UUO). We found that MSCs treatment significantly inhibited fibrosis, and CA pretreatment enhanced the effects of MSCs on fibrosis in vitro. Consistent with the in vitro studies, MSCs alleviated tubular injury and renal fibrosis in mice after UUO, and CA-pretreated MSCs resulted in more significant improvements in tubular injury and renal fibrosis than MSCs after UUO. Moreover, MSCs treatment significantly inhibited necroptosis by repressing the elevation of MLKL, RIPK1, and RIPK3 in PTECs treated by TGF-β1and in mice after UUO, and CA-pretreated MSCs were superior to MSCs in alleviating necroptosis. MSCs significantly reduced TNF-α and TNFR1 expression induced by TGF-β1 in PTECs and inhibited TGF-β1, TNF-α, and TNFR1 expression induced by UUO in mice. These effects of MSCs were significantly enhanced after CA pretreatment. Therefore, our results suggest that CA pretreatment enhances the antifibrotic activity of MSCs by inhibiting TGF-β1/TNF-α/TNFR1 signaling-induced necroptosis.

The Use of Mesenchymal Stem Cells and their Derived Extracellular Vesicles in Cardiovascular Disease Treatment

BACKGROUND

Cardiovascular disease (CVD), including disorders of cardiac muscle and vascular, is the major cause of death globally. Many unsuccessful attempts have been made to intervene in the disease's pathogenesis and treatment. Stem cell-based therapies, as a regeneration strategy, cast a new hope for CVD treatment. One of the most well-known stem cells is mesenchymal stem cells (MSCs), classified as one of the adult stem cells and can be obtained from different tissues. These cells have superior properties, such as proliferation and highly specialized differentiation. On the other hand, they have the potential to modulate the immune system and anti-inflammatory activity. One of their most important features is the secreting the extracellular vesicles (EVs) like exosomes (EXOs) as an intercellular communication system mediating the different physiological and pathophysiological affairs.

METHODS

In this review study, the importance of MSC and its secretory exosomes for the treatment of heart disease has been together and specifically addressed and the use of these promising natural and accessible agents is predicted to replace the current treatment modalities even faster than we imagine.

RESULTS

MSC derived EXOs by providing a pro-regenerative condition allowing innate stem cells to repair damaged tissues successfully. As a result, MSCs are considered as the appropriate cellular source in regenerative medicine. In the plethora of experiments, MSCs and MSC-EXOs have been used for the treatment and regeneration of heart diseases and myocardial lesions.

CONCLUSION

Administration of MSCs has been provided a replacement therapeutic option for heart regeneration, obtaining great attention among the basic researcher and the medical doctors.

Metal-based nanoparticles: Promising tools for the management of cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide. A search for more effective treatments of CVD is increasingly needed. Major advances in nanotechnology opened new avenues in CVD therapeutics. Owing to their special properties, iron oxide, gold and silver nanoparticles (NPs) could exert various effects in the management and treatment of CVD. The role of iron oxide NPs in the detection and identification of atherosclerotic plaques is receiving increased attention. Moreover, these NPs enhance targeted stem cell delivery, thereby potentiating the regenerative capacity at the injured sites. In addition to their antioxidative and antihypertrophic capacities, gold NPs have also been shown to be useful in the identification of plaques and recognition of inflammatory markers. Contrary to first reports suggestive of their cardio-vasculoprotective role, silver NPs now appear to exert negative effects on the cardiovascular system. Indeed, these NPs appear to negatively modulate inflammation and cholesterol uptake, both of which exacerbate atherosclerosis. Moreover, silver NPs may precipitate bradycardia, conduction block and sudden cardiac death. In this review, we dissect the cellular responses and toxicity profiles of these NPs from various perspectives including cellular and molecular ones.

MiR-34a inhibitor protects mesenchymal stem cells from hyperglycaemic injury through the activation of the SIRT1/FoxO3a autophagy pathway

BACKGROUND

Mesenchymal stem cells (MSCs) are favourable treatments for ischaemic diseases; however, MSCs from diabetic patients are not useful for this purpose. Recent studies have shown that the expression of miR-34a is significantly increased in patients with hyperglycaemia; the precise role of miR-34a in MSCs in diabetes needs to be clarified.

OBJECTIVE

The aim of this study is to determine the precise role of miR-34a in MSCs exposed to hyperglycaemia and in recovery heart function after myocardial infarction (MI) in diabetes mellitus (DM) rats.

METHODS

DM rat models were established by high-fat diet combined with streptozotocin (STZ) injection. MSCs were isolated from the bone marrow of donor rats. Chronic culture of MSCs under high glucose was used to mimic the DM micro-environment. The role of miR-34a in regulating cell viability, senescence and paracrine effects were investigated using a cell counting kit-8 (CCK-8) assay, senescence-associated β-galactosidase (SA-β-gal) staining and vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) ELISA, respectively. The expression of autophagy- and senescence-associated proteins in MSCs and silent information regulator 1 (SIRT1) and forkhead box class O 3a (FoxO3a) were analysed by western blotting. Autophagic bodies were analysed by transmission electron microscopy (TEM). The MI model was established by left anterior descending coronary artery (LAD) ligation, and then, the rats were transplanted with differentially treated MSCs intramuscularly at sites around the border zone of the infarcted heart. Thereafter, cardiac function in rats in each group was detected via cardiac ultrasonography at 1 week and 3 weeks after surgery. The infarct size was determined through a 2,3,5-triphenyltetrazolium chloride (TTC) staining assay, while myocardial fibrosis was assessed by Masson staining.

RESULTS

The results of the current study showed that miR-34a was significantly increased under chronic hyperglycaemia exposure. Overexpression of miR-34a was significantly associated with impaired cell viability, exacerbated senescence and disrupted cell paracrine capacity. Moreover, we found that the mechanism underlying miR-34a-mediated deterioration of MSCs exposed to high glucose involved the activation of the SIRT1/FoxO3a autophagy pathway. Further analysis showed that miR-34a inhibitor-treated MSC transplantation could improve cardiac function and decrease the scar area in DM rats.

CONCLUSIONS

Our study demonstrates for the first time that miR-34a mediates the deterioration of MSCs' functions under hyperglycaemia. The underlying mechanism may involve the SIRT1/FoxO3a autophagy signalling pathway. Thus, inhibition of miR-34a might have important therapeutic implications in MSC-based therapies for myocardial infarction in DM patients.

Role of prostaglandin E2 in allogeneic mesenchymal stem cell therapy for cardiac repair

Ischemic heart disease is among the primary causes of cardiovascular-related deaths worldwide. Conventional treatments including surgical interventions and medical therapies aid in preventing further damage to heart muscle but are unable to provide a permanent solution. In recent years, stem cell therapy has emerged as an attractive alternative to restore damaged myocardium after myocardial injury. Allogeneic (donor-derived) mesenchymal stem cells (MSCs) have shown great promise in preclinical and clinical studies, making them the most widely accepted candidates for cardiac cell therapy. MSCs promote cardiac repair by modulating host immune system and secreting various soluble factors, of which prostaglandin E2 (PGE2) is an important one. PGE2 plays a significant role in regulating cardiac remodeling following myocardial injury. In this review, we provide an overview of allogeneic MSCs as candidates for myocardial regeneration with a focus on the role of the PGE2/cyclooxygenase-2 (COX2) pathway in mediating these effects.

Physiological Oxygen Tension Enhances Competence and Functional Properties of Murine Cardiac Mesenchymal Cells

Cardiac mesenchymal cells (CMCs), a newly-discovered and promising type of progenitor cells, are effective in improving cardiac function in rodents after myocardial infarction. Stem/progenitor cells are usually cultured at atmospheric O₂ tension (21%); however, the physiologic O₂ tension in the heart is ~5%, raising the concern that 21% O₂ may cause toxicity due to oxidative stress. Thus, we compared mouse CMCs cultured at 21% or 5% O₂ beginning at passage 2. At passage 5, CMCs underwent severe hypoxic stress (1% O₂ for 24 h). Compared with CMCs cultured at 21% O₂, culture at 5% O₂ consistently improved cell morphology throughout 5 passages, markedly decreased cell size, increased cell number, shortened cell doubling time, and dramatically reduced lactate dehydrogenase release from CMCs into culture media after hypoxic stress. Furthermore, culture at 5% O₂ increased telomerase activity and telomere length, implying that 21% O₂ tension impairs telomerase activity, resulting in telomere shortening and decreased cell proliferation. Thus far, almost all preclinical and clinical studies of cell therapy for the heart disease have used atmospheric (21%) O₂ to culture cells. Our data challenge this paradigm. Our results demonstrate that, compared with 21% O₂, 5% O₂ tension greatly enhances the competence and functional properties of CMCs. The increased proliferation rate at 5% O₂ means that target numbers of CMCs can be achieved with much less time and cost. Furthermore, since this increased proliferation may continue in vivo after CMC transplantation, and since cells grown at 5% O₂ are markedly resistant to severe hypoxic stress, and thus may be better able to survive after transplantation into scarred regions of the heart where O₂ is very low, culture at 5% O₂ may enhance the reparative properties of CMCs (and possibly other cell types). In conclusion, our data support a change in the methods used to culture CMCs and possibly other progenitor cells.

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.

The immunomodulatory effects of mesenchymal stromal cell-based therapy in human and animal models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune inflammatory disease with no absolute cure. Although the exact etiopathogenesis of SLE is still enigmatic, it has been well demonstrated that a combination of genetic predisposition and environmental factors trigger a disturbance in immune responses and thereby participate in the development of this condition. Almost all available therapeutic strategies in SLE are primarily based on the administration of immunosuppressive drugs and are not curative. Mesenchymal stromal cells (MSCs) are a subset of non-hematopoietic adult stem cells that can be isolated from many adult tissues and are increasingly recognized as immune response modulating agents. MSC-mediated inhibition of immune responses is a complex mechanism that involves almost every aspect of the immune response. MSCs suppress the maturation of antigen-presenting cells (DC and MQ), proliferation of T cells (Th1, T17, and Th2), proliferation and immunoglobulin production of B cells, the cytotoxic activity of CTL and NK cells in addition to increasing regulatory cytokines (TGF-β and IL10), and decreasing inflammatory cytokines (IL17, INF-ϒ, TNF-α, and IL12) levels. MSCs have shown encouraging results in the treatment of several autoimmune diseases, in particular SLE. This report aims to review the beneficial and therapeutic properties of MSCs; it also focuses on the results of animal model studies, preclinical studies, and clinical trials of MSC therapy in SLE from the immunoregulatory aspect.

Comparison of the Cardiomyogenic Potency of Human Amniotic Fluid and Bone Marrow Mesenchymal Stem Cells

Background and Objectives

Most studies in cardiac regeneration have explored bone marrow mesenchymal stem cells (BM-MSC) with variable therapeutic effects. Amniotic fluid MSC (AF-MSC) having extended self-renewal and multipotent properties may be superior to bone marrow MSC (BM-MSC). However, a comparison of their cardiomyogenic potency has not been studied yet.

Methods

The 5-azacytidine (5-aza) treated AF-MSC and BM-MSC were evaluated for the expression of GATA-4, Nkx2.5 and ISL-1 transcripts and proteins by quantitative RT-PCR and Western blotting, respectively as well as for the expression of cardiomyogenic differentiation markers cardiac troponin-T (cTNT), beta myosin heavy chain (βMHC) and alpha sarcomeric actinin (ASA) by immunocytochemistry.

Results

The AF-MSC as compared to BM-MSC had significantly higher expression of GATA-4 (183.06±29.85 vs. 9.80±0.05; p<0.01), Nkx2.5 (8.3±1.4 vs. 1.82±0.32; p<0.05), and ISL-1 (39.59±4.05 vs. 4.36±0.39; p<0.01) genes as well as GATA-4 (2.01±0.5 vs. 0.6±0.1; p<0.05), NKx2.5 (1.9±0.14 vs. 0.8±0.2; p<0.01) and ISL-1 (1.7±0.3 vs. 0.9±0.1; p<0.05) proteins. The AF-MSC also had significantly elevated expression of cTNT (5.0×10⁴±0.6×10⁴ vs. 3.5 ×10⁴±0.8×10⁴; p<0.01), β-MHC (15.7×10⁴±0.9×10⁴ vs. 8.2×10⁴±0.6×10⁴; p<0.01) and ASA (18.6×10⁴±4.9×10⁴ vs. 13.1×10⁴±3.0×10⁴; p<0.05) than BM-MSC.

Conclusions

Our data suggest that AF-MSC have greater cardiomyogenic potency than BM-MSC, and thus may be a better source of MSC for therapeutic applications in cardiac regenerative medicine.

Molecular Imaging of Myocardial Inflammation With Positron Emission Tomography Post-Ischemia: A Determinant of Subsequent Remodeling or Recovery

Inflammation after myocardial ischemia influences ventricular remodeling and repair and has emerged as a therapeutic target. Conventional diagnostic measurements address systemic inflammation but cannot quantify local tissue changes. Molecular imaging facilitates noninvasive assessment of leukocyte infiltration into damaged myocardium. Preliminary experience with ¹⁸F-labeled fluorodeoxyglucose ([¹⁸F]FDG) demonstrates localized inflammatory cell signal within the infarct territory as an independent predictor of subsequent ventricular dysfunction. Novel targeted radiotracers may provide additional insight into the enrichment of specific leukocyte populations. Challenges to wider implementation of inflammation imaging after myocardial infarction include accurate and reproducible quantification, prognostic value, and capacity to monitor inflammation response to novel treatment. This review describes myocardial inflammation following ischemia as a molecular imaging target and evaluates established and emerging radiotracers for this application. Furthermore, the potential role of inflammation imaging to provide prognostic information, support novel drug and therapeutic research, and assess biological response to cardiac disease is discussed.

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.

MicroRNA-29b-3p Targets SPARC Gene to Protect Cardiocytes against Autophagy and Apoptosis in Hypoxic-Induced H9c2 Cells

MicroRNAs participate in the regulation of abnormal cardiomyocyte apoptosis and autophagy, which leads to heart failure (HF). Lower miR-29b-3p levels were found in HF patients in this study. However, the role of miR-29b-3p in the molecular pathogenesis of HF remains unclear. Hypoxia-stimulated H9c2 cells were used an in vitro model of HF. It was found that hypoxia stimulation decreased the miR-29b-3p expression and enhanced cell apoptosis and autophagy response in H9c2 cells. While the effects of hypoxia on cell apoptosis and autophagy were reversed by miR-29b-3p transfection, especially 100 nM. The secreted protein acidic and rich in cysteine (SPARC), predicted as a direct target of miR-29b-3p, aggravated the hypoxia-induced cells apoptosis, autophagy, and TGFβ1/Smad3 activation. While the changes were dramatically reversed by miR-29b-3p. Taken together, our data suggest that miR-29b-3p plays an important role in the progression of HF through targeting SPARC and regulating TGFβ1/Smad3 pathway.

Functionally Improved Mesenchymal Stem Cells to Better Treat Myocardial Infarction

Myocardial infarction (MI) is one of the leading causes of death worldwide. Mesenchymal stem cell (MSC) transplantation is considered a promising approach and has made significant progress in preclinical studies and clinical trials for treating MI. However, hurdles including poor survival, retention, homing, and differentiation capacity largely limit the therapeutic effect of transplanted MSCs. Many strategies such as preconditioning, genetic modification, cotransplantation with bioactive factors, and tissue engineering were developed to improve the survival and function of MSCs. On the other hand, optimizing the hostile transplantation microenvironment of the host myocardium is also of importance. Here, we review the modifications of MSCs as well as the host myocardium to improve the efficacy of MSC-based therapy against MI.

Adjuvant role of macrophages in stem cell-induced cardiac repair in rats

Bone marrow-derived mesenchymal stem cells (BMMSCs) are used extensively for cardiac repair and interact with immune cells in the damaged heart. Macrophages are known to be modulated by stem cells, and we hypothesized that priming macrophages with BMMSCs would enhance their therapeutic efficacy. Rat bone marrow-derived macrophages (BMDMs) were stimulated by lipopolysaccharide (LPS) with or without coculture with rat BMCs. In the LPS-stimulated BMDMs, induction of the inflammatory marker iNOS was attenuated, and the anti-inflammatory marker Arg1 was markedly upregulated by coculture with BMMSCs. Myocardial infarction (MI) was induced in rats. One group was injected with BMMSCs, and a second group was injected with MIX (a mixture of BMMSCs and BMDMs after coculture). The reduction in cardiac fibrosis was greater in the MIX group than in the BMC group. Cardiac function was improved in the BMMSC group and was substantially improved in the MIX group. Angiogenesis was better in the MIX group, and anti-inflammatory macrophages were more abundant in the MIX group than in the BMMSC group. In the BMMSCs, interferon regulatory factor 5 (IRF5) was exclusively induced by coculture with macrophages. IRF5 knockdown in BMMSCs failed to suppress inflammatory marker induction in the macrophages. In this study, we demonstrated the successful application of BMDMs primed with BMMSCs as an adjuvant to cell therapy for cardiac repair.

The Effect and Mechanism of Chinese Herbal Formula Sini Tang in Heart Failure after Myocardial Infarction in Rats

OBJECTIVE

To investigate the effectiveness and mechanism of the Chinese herbal formula Sini Tang (SNT) which consists of Aconitum carmichaelii (Fuzi), Zingiber officinale (Gan Jiang), and Glycyrrhiza uralensis (Gancao) in heart failure after myocardial infarction in rats.

METHODS

We established the heart failure after myocardial infarction in model of SD rats by ligating the anterior descending branch of left coronary artery. Rats were randomly divided into six experimental groups: Sham operation group, HF group, Benazepril group, high dose of SNT group, medium dose of SNT group, and low dose of SNT group. Drugs were administered by oral gavage for eight weeks. The detection indexes include left ventricular function by echocardiogram, Collagen Volume Fraction by Masson staining, level of Plasma Renin, Angiotensin II and Aldosterone by radioimmunoassay, protein and gene level of ACE and AT1R by western-blot, and real-time PCR.

RESULTS

The outcomes of this study indicated that SNT significantly improved the LVEF and LVFS, thickened both LVAWd and LVAWs, and reduced LVIDs in heart failure after myocardial infarction in rats when compared with control group (P < 0.05). Besides, SNT significantly reduced the Collagen Volume Fraction (P < 0.05). The results of radioimmunoassay showed that SNT decreased the level of Plasma Renin, Angiotensin II, and Aldosterone (P < 0.05). The outcomes of western-blot and real-time PCR analysis showed that SNT significantly downregulated the protein and gene level of ACE and AT1R (P < 0.05).

CONCLUSIONS

The Chinese herbal formula SNT could improve left ventricular systolic function in heart failure after myocardial infarction in rats and decreased the level of Plasma Renin, Angiotensin II, and Aldosterone, as well as downregulating the protein and gene level of ACE and AT1R. Therefore, SNT has potential benefits of improving cardiac function by inhibiting the excessive activation of Renin-Angiotensin-Aldosterone system in heart failure after myocardial infarction in rats.