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

Exosomes derived from baicalin‑pretreated mesenchymal stem cells mitigate atherosclerosis by regulating the SIRT1/NF‑κB signaling pathway

Atherosclerosis (AS) is a disease with high global incidence and mortality rates. Currently, the treatment of AS in clinical practice carries a high risk of adverse effects and toxic side effects. The pretreatment of mesenchymal stem cells (MSCs) with drugs may enhance the bioactivity of MSC‑derived exosomes (MSC‑exos), which could be a promising candidate for inhibiting the progression of AS. The aim of the present study was to investigate the ability of exos derived from baicalin‑preconditioned MSCs (Ba‑exos) to exhibit an inhibitory effect on AS progression and to explore the potential molecular mechanisms. Exos were isolated from untreated MSCs and MSCs pretreated with Ba, and were characterized using transmission electron microscopy, nanoparticle tracking analysis and western blotting. Subsequently, Cell Counting Kit‑8 and Transwell assays, reverse transcription‑quantitative PCR, immunofluorescence, western blotting and ELISA were used to evaluate the effects of Ba‑exos on AS, and the possible molecular mechanisms. Oil Red O and Masson staining were used to assess AS pathological tissue in a high‑fat diet‑induced mouse model of AS. Notably, MSC‑exos and Ba‑exos were successfully isolated. Compared with MSC‑exos, Ba‑exos demonstrated superior inhibitory effects on the viability and migration, and the levels of inflammatory factors in oxidized low‑density lipoprotein (ox‑LDL)‑induced vascular smooth muscle cells (VSMCs). Additionally, compared with MSC‑exos, Ba‑exos significantly inhibited NF‑κB activation by upregulating sirtuin 1 (SIRT1), thereby suppressing inflammation in ox‑LDL‑induced VSMCs to a greater extent. In mice with high‑fat diet‑induced AS, Ba‑exos exhibited the ability to inhibit AS plaque formation and to alleviate AS progression by reducing the levels of inflammatory factors compared with MSC‑exos; however, the difference was not significant. In conclusion, Ba‑exos may serve as a potential strategy for treating AS by regulating the SIRT1/NF‑κB signaling pathway to suppress inflammation.

Identification of the crucial roles of BAXhigh NK cells in human derived mesenchymal stem cell therapy for chronic heart failure patients

Mesenchymal stem cells (MSCs) have demonstrated significant potential in heart failure (HF) treatment, but the exact mechanisms are still not fully understood. This research utilized single-cell RNA sequencing to examine alterations in peripheral blood mononuclear cells from heart failure patients pre- and post-MSC therapy. Moreover, we utilized Mendelian randomization (MR) analysis to identify causal genes linked to HF. Specifically, through scRNA-seq, we observed a progressive increase in Natural Killer (NK) cells within peripheral blood mononuclear cells (PBMCs) following MSC treatment. Furthermore, MR analysis identified the differentially expressed gene (DEG) BAX as a potential target gene for HF. Notably, the expression of BAX was significantly downregulated after MSC treatment, suggesting its potential as a therapeutic response biomarker. Cell-cell communication analysis revealed that BAXhigh NK cells displayed reduced cell-cell communication and increased apoptotic activity. Enrichment analysis indicated an association between BAXhigh NK cells and the "coagulant" pathway. Taken together, our findings suggest that BAX may contribute to the pathogenesis of HF by promoting coagulation and apoptotic pathways. In contrast, MSCs appear to suppress BAX expression, thereby inhibiting these pathways. MSC treatment increases the proportion of NK cells and reduces BAXhigh NK cells, ultimately improving NK cell function, and ameliorating HF.

Immunomodulatory effects of mesenchymal stem cell therapy in chronic kidney disease: a literature review

Chronic kidney disease (CKD) has been a growing public medical concern in recent years which calls for effective interventions. Mesenchymal stem cells (MSCs) have garnered increased interest in past decades due to their potential to repair and regenerate damaged tissues. Many clinical trials have highlighted the safety and effectiveness of kidney disease with this novel cell therapy. MSC infusion can improve renal function indices such as glomerular filtration rate, urine protein, serum creatinine, and blood urea nitrogen, while inhibiting immune response by increasing regulatory T cells. The therapeutic mechanisms may be primarily attributed to a function combined with immunomodulation, anti-inflammation, anti-fibrosis, promoting angiogenesis, anti-oxidation, anti-apoptosis, or tissue healing produced by cell secretsome. However, CKD is a broad concept due to many pathological etiologies including diabetes, hypertension, heart disease, immunological damage, a family history of renal failure, and so on. Furthermore, the therapeutic efficacy of MSCs may be influenced by different cell sources, injection methods, medication dosage, or homing proportion. As a result, it is timely and essential to access recent advancements in the MSC application on CKD.

Cardiac tissue regeneration by microfluidic generated cardiac cell-laden calcium alginate microgels and mesenchymal stem cell extracted exosomes on myocardial infarction model

Regenerative medicine is one of the effective approaches for myocardial infarcted (MI) tissue due to the low capacity of heart for regeneration. However, cell therapy with local administration has shown poor cell retention in the targeted area and limited engraftment capacity at the intended location, resulting in inadequate tissue regeneration. The present study involves mesenchymal stem cell-derived exosomes and encapsulated cells in small and injectable calcium alginate microgels by a specialized microfluidic device to decrease inflammation and increase cell retention in the infarcted tissue. The results have shown that our microfluidic system can produce monodisperse cardiac cell-laden alginate microgels within the size range of <100 μm that are easily injectable. Our in vivo findings on the MI rat model demonstrated that the combination of cardiac cell-laden calcium alginate microgels with mesenchymal stem cells derived exosomes resulted in a higher increase in echocardiography, heart-specific gene expressions, and cardiac markers results compared to the other groups. However, the administration of exosomes or cardiac cells separately has shown a small amount of regeneration. Encapsulating cardiac cells of specific sizes along with exosomes produced from mesenchymal stem cells can be potentially applied as an effective method for regenerating the myocardium following infarction.

Competitive signaling and cellular communications in myocardial infarction response

Cell communication and competition pathways are malleable to Myocardial Infarction (MI). Key signals, transcriptive regulators, and metabolites associated with apoptotic responses such as Myc, mTOR, and p53 are important players in the myocardium. The individual state of cardiomyocytes, fibroblasts, and macrophages in the heart tissue are adaptable in times of stress. The overlapping communication pathways of Wnt/β-catenin, Notch, and c-Kit exhibit the involvement of important factors in cell competition in the myocardium. Depending on the effects of these pathways on genetic expression and signal amplification, the proliferative capacities of the previously stated cells that make up the myocardium, amplify or diminish. This creates a distinct classification of "fit" and "unfit" cells. Beyond straightforward traits, the intricate metabolite interactions between neighboring cells unveil a complex battle. Strategic manipulation of these pathways holds translational promise for rapid cardiac recovery post-trauma.

Interleukin-1β-stimulated macrophage-derived exosomes improve myocardial injury in sepsis via regulation of mitochondrial homeostasis: experimental research

BACKGROUND

The purpose of this study was to investigate the effects of interleukin-1β (IL-1β) stimulation on the protection of macrophage-derived exosomes miR-146a (M-IL-exo-146a) on sepsis-induced myocardial injury (SMI) in vitro and in vivo .

MATERIALS AND METHODS

Macrophage-derived exosomes (M-exo) and IL-1β-stimulated macrophage exosomes (M-IL-exo) were isolated from macrophages of sepsis with or without IL-1β. The expressions of miR-146a in M-exo and M-IL-exo were detected by fluorescence quantitative PCR. Related molecular biology technologies were used to evaluate the role and mechanism of M-exo-146a and M-IL-exo-146a on SMI and the enhancing effect of IL-1β.

RESULTS

Compared with M-exo, the expression of miR-146a in M-IL-exo was significantly increased. M-IL-exo-146a significantly alleviated SMI by decreasing the level of serum myocardial enzymes, serum and myocardial oxidative stress and cytokines, and improved myocardial mitochondrial imbalance. The mechanism responsible for IL-1β enhancing the production of IL-M-exo miR-146a was via JNK-1/2 signal pathway. The mechanism responsible for M-exo-IL-miR-146a protecting SMI was related to miR-146a inhibiting inflammatory response and mitochondrial function via MAPK4/Drp-1 signal pathway.

CONCLUSIONS

This study provides a new strategy for the treatment of SMI by delivering M-IL-exo.

Mesenchymal Stromal Cell (MSC) Isolation and Induction of Acute and Replicative Senescence

Mesenchymal stromal cells (MSCs) are a heterogeneous population of non-hematopoietic adult stem cells derived from the embryonic mesoderm. They possess self-renewal and multipotent differentiation capabilities, allowing them to give rise to mesodermal cell types, such as osteoblasts, chondroblasts, and adipocytes, as well as non-mesodermal cells, including neuron-like cells and endothelial cells. MSCs play a vital role in maintaining homeostasis across various tissues by facilitating tissue repair, immune regulation, and inflammatory response balance. Initially identified in bone marrow, MSCs have since been found in multiple tissues, including muscle, adipose tissue, and dental pulp, and are characterized by specific surface markers and differentiation abilities.Aging induces cellular senescence, an irreversible growth arrest linked to various stressors, which has significant implications for regenerative medicine. While initially viewed as a protective mechanism against tumorigenesis, the accumulation of senescent cells, particularly in MSCs, leads to age-related diseases through the senescence-associated secretory phenotype (SASP). The onset of senescence in MSCs diminishes their therapeutic potential and contributes to homeostatic imbalance. Key drivers of MSC senescence include genetic damage, noncoding RNA, and mitochondrial dysfunction, among others.This study outlines the principal methodologies for the isolation and characterization of MSCs, alongside techniques to induce acute senescence via hydrogen peroxide or irradiation, as well as replicative senescence, to investigate senescence-related changes in vitro. Understanding the mechanisms of MSC senescence will provide critical insights into the molecular pathways of aging and pave way for advancements in cellular therapies targeting age-related diseases.

Stem cells and bio scaffolds for the treatment of cardiovascular diseases: new insights

Mortality and morbidity from cardiovascular diseases are common worldwide. In order to improve survival and quality of life for this patient population, extensive efforts are being made to establish effective therapeutic modalities. New treatment options are needed, it seems. In addition to treating cardiovascular diseases, cell therapy is one of the most promising medical platforms. One of the most effective therapeutic approaches in this area is stem cell therapy. In stem cell biology, multipotent stem cells and pluripotent stem cells are divided into two types. There is evidence that stem cell therapy could be used as a therapeutic approach for cardiovascular diseases based on multiple lines of evidence. The effectiveness of stem cell therapies in humans has been studied in several clinical trials. In spite of the challenges associated with stem cell therapy, it appears that resolving them may lead to stem cells being used in cardiovascular disease patients. This may be an effective therapeutic approach. By mounting these stem cells on biological scaffolds, their effect can be enhanced.

Magnetic soft microrobots for erectile dysfunction therapy

Erectile dysfunction (ED) is a major threat to male fertility and quality of life, and mesenchymal stromal cells (MSCs) are a promising therapeutic option. However, therapeutic outcomes are compromised by low MSC retention and survival rates in corpus cavernosum tissue. Here, we developed an innovative magnetic soft microrobot comprising an ultrasoft hydrogel microsphere embedded with a magnetic nanoparticle chain for MSC delivery. This design also features phenylboronic acid groups for scavenging reactive oxygen species (ROS). With a Young's modulus of less than 1 kPa, the ultrasoft microrobot adapts its shape within narrow blood vessels, ensuring a uniform distribution of MSCs within the corpus cavernosum. Our findings showed that compared with traditional MSC injections, the MSC delivery microrobot (MSC-Rob) significantly enhanced MSC retention and survival. In both rat and beagle ED models, MSC-Rob treatment accelerated the repair of corpus cavernosum tissue and restored erectile function. Single-cell RNA sequencing (scRNA-seq) revealed that MSC-Rob treatment facilitates nerve and blood vessel regeneration in the corpus cavernosum by increasing the presence of regenerative macrophages. Overall, our MSC-Rob not only advances the clinical application of MSCs for ED therapy but also broadens the scope of microrobots for other cell therapies.

Exploring Mesenchymal Stem Cells versus Minoxidil for Androgenic Alopecia Treatment: A Detailed Animal-Based Histological and Morphometric Study

INTRODUCTION

Androgenic alopecia (AGA), a hair loss condition caused by dihydrotestosterone binding to hair follicle receptors, negatively impacts quality of life for both men and women. Current treatments like minoxidil and finasteride have limitations, highlighting the need for alternative therapies, such as human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs).

METHODS

In this study, forty-eight adult male Wistar albino rats (3 months old) were used. The control group (Group I) received no treatment, while the other rats underwent AGA induction via daily subcutaneous testosterone injections (100 mg/kg). These rats developed alopecia and were divided into three groups: AGA (Group II), AGA plus daily minoxidil spray (Group III), and AGA plus a single intradermal injection of HUCB-MSCs (1 mL containing 1 × 105 cells, Group IV). After 4 weeks, the rats were sacrificed, and skin specimens were prepared for histological analysis using H&E, Masson's trichrome, and immunohistochemical staining for CK 19, vascular endothelial growth factor (VEGF), and TUNEL antibodies.

RESULTS

It was shown that HUCB-MSC treatment reversed structural damage to hair and follicles, normalizing conditions within 1-week post-injection. The treatment enhanced the anagen phase, suppressed telogen and catagen phases, reduced apoptosis, and increased VEGF and CK 19 immune reactions. Observational follow-up for Groups III and IV revealed that while the minoxidil group experienced significant hair loss after 37 days, the stem cell group exhibited dense and long hair covering the treated area.

CONCLUSION

HUCB-MSC therapy demonstrated superior efficacy over minoxidil with no observed side effects, indicating its potential as a promising alternative for AGA treatment.

Mesenchymal Stem Cells Increase Resistance Against Ventricular Arrhythmias Provoked in Rats with Myocardial Infarction

This study evaluated the role of the mesenchymal stem cells derived from adipose tissue (MSCs) in provoked ventricular arrhythmias (VAs) in animals with myocardial infarction (MI). The experimental groups were: sham, subjected to sham surgery and intramyocardial saline injection; MIV, infarcted rats subjected to intramyocardial saline injection; MI + MSCs, infarcted rats subjected to intramyocardial MSCs injection. Injections were performed two days after infarction and the arrhythmogenic inducibility experiment was performed the next day. Only 35% of the MI + MSCs group developed VAs, while the one in the MIV group was 65%. The proportion of nonsustained ventricular tachycardia, sustained tachycardia, and ventricular fibrillation was similar between the infarcted groups, but MSCs animals had shorter duration of nonsustained ventricular tachycardia. However, MSCs increased connexin 43 content in the remote area, even above the levels found in the sham group. MSCs prevented the increase of IL-1β in the different areas of the myocardium. There was higher carbonylation and content of 4-hydroxynonenal (4-HNE, a marker of lipoperoxidation) in the myocardium of infarcted rats, but MSCs attenuated the increase of 4-HNE in the infarcted area. In conclusion, MSCs have a protective effect against the development of arrhythmias, but do not imply a significant benefit for animals that have developed VAs. It is possible to think that the cardioprotection of MSCs involves anti-inflammatory/oxidative actions and improvement in the formation of communicating junctions.Graphical abstract.

Promotion of osteochondral repair through immune microenvironment regulation and activation of endogenous chondrogenesis via the release of apoptotic vesicles from donor MSCs

Utilizing transplanted human umbilical cord mesenchymal stem cells (HUMSCs) for cartilage defects yielded advanced tissue regeneration, but the underlying mechanism remain elucidated. Early after HUMSCs delivery to the defects, we observed substantial apoptosis. The released apoptotic vesicles (apoVs) of HUMSCs promoted cartilage regeneration by alleviating the chondro-immune microenvironment. ApoVs triggered M2 polarization in macrophages while simultaneously facilitating the chondrogenic differentiation of endogenous MSCs. Mechanistically, in macrophages, miR-100-5p delivered by apoVs activated the MAPK/ERK signaling pathway to promote M2 polarization. In MSCs, let-7i-5p delivered by apoVs promoted chondrogenic differentiation by targeting the eEF2K/p38 MAPK axis. Consequently, a cell-free cartilage regeneration strategy using apoVs combined with a decellularized cartilage extracellular matrix (DCM) scaffold effectively promoted the regeneration of osteochondral defects. Overall, new mechanisms of cartilage regeneration by transplanted MSCs were unconcealed in this study. Moreover, we provided a novel experimental basis for cell-free tissue engineering-based cartilage regeneration utilizing apoVs.

GATA-4 overexpressing BMSC-derived exosomes suppress H/R-induced cardiomyocyte ferroptosis

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes overexpressing GATA-4 (Exosoe-GATA-4) can protect cardiac function. Mitochondrial permeability transition pore (mPTP) has a crucial role in ferroptosis. This study aimed to assess the mechanism of Exosoe-GATA-4 in myocardial ischemia/reperfusion (I/R) injury. Exos were successfully excreted, and 185 differential expression miRNAs were obtained using bioinformatics. The Exosoe-GATA-4 effectively suppressed hypoxia/reoxygenation (H/R)-induced cardiomyocytes' ferroptosis, while the effects were reversed by miR-330-3p inhibitor. miR-330-3p targeted negative regulated BAP1. The effects of miR-330-3p inhibitor were reversed by knock-down BAP1. Also, BAP1 reversed the effects of Exosoe-GATA-4 on H/R-induced cardiomyocytes' ferroptosis by downregulating SLC7A11. Mechanistically, BAP1 interacted with IP3R and increased cardiomyocytes' Ca2+ level, causing mPTP opening and mitochondrial dysfunction, promoting H/R-induced cardiomyocytes' ferroptosis. Moreover, hydrogen sulfide (H2S) content was increased and regulated the keap1/Nrf2 signaling pathway by Exosoe-GATA-4 treated. Exosoe-GATA-4 effectively suppresses H/R-induced cardiomyocytes' ferroptosis by upregulating miR-330-3p, which regulates the BAP1/SLC7A11/IP3R axis and inhibits mPTP opening.

Genetically modified mesenchymal stromal cells: a cell-based therapy offering more efficient repair after myocardial infarction

Myocardial infarction (MI) is a serious complication of coronary artery disease. This condition is common worldwide and has a profound impact on patients' lives and quality of life. Despite significant advances in the treatment of heart disease in modern medicine, the efficient treatment of MI still faces a number of challenges. Problems such as scar formation and loss of myocardial function after a heart attack still limit patients' recovery. Therefore, the search for a new therapeutic tool that can promote repair and regeneration of myocardial tissue has become crucial. In this context, mesenchymal stromal cells (MSCs) have attracted much attention as a potential therapeutic tool. MSCs are a class of adult stem cells with multidirectional differentiation potential, derived from bone marrow, fat, placenta and other tissues, and possessing properties such as self-renewal and immunomodulation. The application of MSCs may provide a new direction for the treatment of MI. These stem cells have the potential to differentiate into cardiomyocytes and vascular endothelial cells in damaged tissue and to repair and protect myocardial tissue through anti-inflammatory, anti-fibrotic and pro-neovascularization mechanisms. However, the clinical results of MSCs transplantation for the treatment of MI are less satisfactory due to the limitations of the native function of MSCs. Genetic modification has overcome problems such as the low survival rate of transplanted MSCs in vivo and enhanced their functions of promoting neovascularization and differentiation into cardiomyocytes, paving the way for them to become an effective tool for repair therapy after MI. In previous studies, MSCs have shown some therapeutic potential in experimental animals and preliminary clinical trials. This review aims to provide readers with a comprehensive and in-depth understanding to promote the wider application of engineering MSCs in the field of MI therapy, offering new hope for recovery and improved survival of cardiac patients.

Optimizing Cardiomyocyte Differentiation: Comparative Analysis of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells in Rats Using 5-Azacytidine and Low-Dose FGF and IGF Treatment

Mesenchymal stem cells (MSCs) exhibit multipotency, self-renewal, and immune-modulatory properties, making them promising in regenerative medicine, particularly in cardiovascular treatments. However, optimizing the MSC source and induction method of cardiac differentiation is challenging. This study compares the cardiomyogenic potential of bone marrow (BM)-MSCs and adipose-derived (AD)-MSCs using 5-Azacytidine (5-Aza) alone or combined with low doses of Fibroblast Growth Factor (FGF) and Insulin-like Growth Factor (IGF). BM-MSCs and AD-MSCs were differentiated using two protocols: 10 μmol 5-Aza alone and 10 μmol 5-Aza with 1 ng/mL FGF and 10 ng/mL IGF. Morphological, transcriptional, and translational analyses, along with cell viability assessments, were performed. Both the MSC types exhibited similar morphological changes; however, AD-MSCs achieved 70-80% confluence faster than BM-MSCs. Surface marker profiling confirmed CD29 and CD90 positivity and CD45 negativity. The differentiation protocols led to cell flattening and myotube formation, with earlier differentiation in AD-MSCs. The combined protocol reduced cell mortality in BM-MSCs and enhanced the expression of cardiac markers (MEF2c, Troponin I, GSK-3β), particularly in BM-MSCs. Immunofluorescence confirmed cardiac-specific protein expression in all the treated groups. Both MSC types exhibited the expression of cardiac-specific markers indicative of cardiomyogenic differentiation, with the combined treatment showing superior efficiency for BM-MSCs.

Mesenchymal stromal cell-derived exosomes protect against abdominal aortic aneurysm formation through CD74 modulation of macrophage polarization in mice

BACKGROUND

Mesenchymal stromal cell (MSC)-derived exosomes (MSC-Exo) have been recognized for their significant role in regulating macrophage polarization, a process crucial to the pathogenesis of abdominal aortic aneurysm (AAA). However, the therapeutic effects of MSC-Exo on AAA remain largely unexplored. Therefore, this study aimed to investigate the functional and mechanistic aspects of MSC-Exo in the progression of AAA.

METHODS

The MSC-derived exosomes were characterized using Transmission Electron Microscopy, Nanoparticle Tracking Analysis, and Western blotting. An experimental mouse model of AAA was established through the administration of angiotensin II (Ang II) in male apoe-/- mice and calcium chloride (CaCl2) in male C57/B6 mice, with subsequent tail vein injection of exosomes to evaluate their efficacy against AAA. Macrophage polarization was assessed using immunofluorescence staining and WB analysis. Mechanistic analysis was performed using 4D Label-free Proteomics analysis.

RESULTS

We found that intravenous administration of MSC-Exo induced M2 polarization of macrophages within an inflammatory environment, effectively impeding AAA development in Ang II or CaCl2-induced AAA model. The therapeutic efficacy of MSC-Exo treatment was dependent on the presence of macrophages. Mechanistically, MSC-Exo suppressed the levels of cluster of differentiation 74 (CD74), modulating macrophage polarization through the TSC2-mTOR-AKT pathway. These findings highlight the potential of MSC-Exo as a therapeutic strategy for AAA by modulating macrophage polarization.

Mesenchymal stem cells as future treatment for cardiovascular regeneration and its challenges

Cardiovascular diseases (CVDs), particularly stroke and myocardial infarction (MI) contributed to the leading cause of death annually among the chronic diseases globally. Despite the advancement of technology, the current available treatments mainly served as palliative care but not treating the diseases. However, the discovery of mesenchymal stem cells (MSCs) had gained a consideration to serve as promising strategy in treating CVDs. Recent evidence also showed that MSCs are the strong candidate to be used as stem cell therapy involving cardiovascular regeneration due to its cardiomyogenesis, anti-inflammatory and immunomodulatory properties, antifibrotic effects and neovascularization capacity. Besides, MSCs could be used for cellular cardiomyoplasty with its transdifferentiation of MSCs into cardiomyocytes, paracrine effects, microvesicles and exosomes as well as mitochondrial transfer. The safety and efficacy of utilizing MSCs have been described in well-established preclinical and clinical studies in which the accomplishment of MSCs transplantation resulted in further improvement of the cardiac function. Tissue engineering could enhance the desired properties and therapeutic effects of MSCs in cardiovascular regeneration by genome-editing, facilitating the cell delivery and retention, biomaterials-based scaffold, and three-dimensional (3D)-bioprinting. However, there are still obstacles in the use of MSCs due to the complexity and versatility of MSCs, low retention rate, route of administration and the ethical and safety issues of the use of MSCs. The aim of this review is to highlight the details of therapeutic properties of MSCs in treating CVDs, strategies to facilitate the therapeutic effects of MSCs through tissue engineering and the challenges faced using MSCs. A comprehensive review has been done through PubMed and National Center for Biotechnology Information (NCBI) from the year of 2010 to 2021 based on some specific key terms such as 'mesenchymal stem cells in cardiovascular disease', 'mesenchymal stem cells in cardiac regeneration', 'mesenchymal stem cells facilitate cardiac repairs', 'tissue engineering of MSCs' to include relevant literature in this review.

Surgical Management of Ischemic Cardiomyopathy Patients with Severe Left Ventricular Dysfunction: Is It Time to Reconsider Revascularization Surgery?

Ischemic cardiomyopathy patients with severe left ventricular dysfunction are a specific group of patients with poor surgical outcomes. There are few surgical treatment options in practice for the treatment of these patients such as heart transplantation, coronary artery bypass surgery, surgical ventricular restoration, etc. Despite multiple treatment options, there are no explicit clinical guidelines available to guide surgeons in choosing the most appropriate option and ensuring that the specific patient can benefit from the selected surgical treatment. Heart transplantation is the gold standard treatment for ischemic cardiomyopathy patients with severe left ventricular dysfunction, but it is limited to very few highly equipped centers around the world due to donor shortages, complex perioperative and surgical management, and limited technological and human resources. It is evident from some studies that heart transplant-eligible candidates can benefit from alternative surgical options such as coronary artery bypass surgery alone or combined with surgical ventricular restoration. Therefore, alternative surgical options that are used for most of the population, especially in developing and underdeveloped countries, need to be discussed to improve their outcomes. A challenge in the recent era which has yet to find a solution is to determine which heart transplant candidate can benefit from simple revascularization compared to a complex heart transplantation procedure. Myocardial viability testing was one of the most important determinants in deciding whether a patient should undergo revascularization, but its role in guiding appropriate surgical options has been challenged. This review aims to discuss the available surgical management options and their long-term outcomes for patients with ischemic cardiomyopathy, which will eventually help surgeons when choosing a surgical procedure.

Nanoengineered Silica-Based Biomaterials for Regenerative Medicine

The paradigm of regenerative medicine is undergoing a transformative shift with the emergence of nanoengineered silica-based biomaterials. Their unique confluence of biocompatibility, precisely tunable porosity, and the ability to modulate cellular behavior at the molecular level makes them highly desirable for diverse tissue repair and regeneration applications. Advancements in nanoengineered silica synthesis and functionalization techniques have yielded a new generation of versatile biomaterials with tailored functionalities for targeted drug delivery, biomimetic scaffolds, and integration with stem cell therapy. These functionalities hold the potential to optimize therapeutic efficacy, promote enhanced regeneration, and modulate stem cell behavior for improved regenerative outcomes. Furthermore, the unique properties of silica facilitate non-invasive diagnostics and treatment monitoring through advanced biomedical imaging techniques, enabling a more holistic approach to regenerative medicine. This review comprehensively examines the utilization of nanoengineered silica biomaterials for diverse applications in regenerative medicine. By critically appraising the fabrication and design strategies that govern engineered silica biomaterials, this review underscores their groundbreaking potential to bridge the gap between the vision of regenerative medicine and clinical reality.

The effect of macrophages and their exosomes in ischemic heart disease

Ischemic heart disease (IHD) is a leading cause of disability and death worldwide, with immune regulation playing a crucial role in its pathogenesis. Various immune cells are involved, and as one of the key immune cells residing in the heart, macrophages play an indispensable role in the inflammatory and reparative processes during cardiac ischemia. Exosomes, extracellular vesicles containing lipids, nucleic acids, proteins, and other bioactive molecules, have emerged as important mediators in the regulatory functions of macrophages and hold promise as a novel therapeutic target for IHD. This review summarizes the regulatory mechanisms of different subsets of macrophages and their secreted exosomes during cardiac ischemia over the past five years. It also discusses the current status of clinical research utilizing macrophages and their exosomes, as well as strategies to enhance their therapeutic efficacy through biotechnology. The aim is to provide valuable insights for the treatment of IHD.

Effect of human periodontal ligament stem cell-derived exosomes on cementoblast activity

OBJECTIVES

Exosomes derived from stem cells are a potential cell-free tool for tissue regeneration with therapeutic potential. However, its application in cementum repair is unclear. This study aimed to investigate the effect of human periodontal ligament stem cell-derived exosomes on the biological activity of cementoblasts, the main effector cells in cementum synthesis.

MATERIALS AND METHODS

OCCM-30 cementoblasts were cultured with various human periodontal ligament stem cell-derived exosome concentrations. OCCM-30 cells proliferation, migration, and cementogenic mineralization were examined, along with the gene and protein expression of factors associated with cementoblastic mineralization.

RESULTS

Exosomal promoted the migration, proliferation, and mineralization of OCCM-30 cells. The exosome-treated group significantly increased the expression of cementogenic-related genes and proteins. Furthermore, the expression of p-PI3K and p-AKT was enhanced by exosome administration. Treatment with a PI3K/AKT inhibitor markedly attenuated the gene and protein expression of cementoblastic factors, and this effect was partially reversed by exosome administration.

CONCLUSIONS

Human periodontal ligament stem cell-derived exosomes can promote the activity of cementoblasts via the PI3K/AKT signaling pathway, providing a scientific basis for promoting the repair process in orthodontically induced inflammatory root resorption.

Safety and efficacy of umbilical cord tissue-derived mesenchymal stem cells in the treatment of patients with aging frailty: a phase I/II randomized, double-blind, placebo-controlled study

BACKGROUND

Mesenchymal stem cells (MSCs) hold a great promise for cell-based therapy in the field of regenerative medicine. In this study, we aimed to evaluate the safety and efficacy of intravenous infusion of human umbilical cord-derived MSCs (HUC-MSCs) in patients with aging frailty.

METHODS

In this randomized, double-blind, placebo-controlled trial, participants diagnosed with aging frailty were randomly assigned to receive intravenous administrations of HUC-MSCs or placebo. All of serious adverse events and AEs were monitored to evaluate the safety of treatment during the 6-month follow-up. The primary efficacy endpoint was alteration of physical component scores (PCS) of SF-36 qualities of life at 6 months. The secondary outcomes including physical performance tests and pro-inflammatory cytokines, were also observed and compared at each follow-up visits. All evaluations were performed at 1 week, 1, 2, 3 and 6 months following the first intravenous infusion of HUC-MSCs.

RESULTS

In the MSCs group, significant improvements in PCS of SF-36 were observed from first post-treatment visit and sustained throughout the follow-up period, with greater changes compared to the placebo group (p = 0.042). EQ-VAS scores of MSCs group improved significantly at 2 month (p = 0.023) and continued until the end of the 6-month visit (p = 0.002) in comparison to the placebo group. The timed up and go (TUG) physical performance test revealed significant group difference and showed continual enhancements over 6 months (p < 0.05). MSC transplantation improved the function of 4-m walking test (4MWT) compared with the placebo group with a decrease of 2.05 s at 6 months of follow-up (p = 0.21). The measurement of grip strength revealed group difference with MSCs group demonstrating better performance, particularly at 6 months (p = 0.002). Inflammatory cytokines (TNF-α, IL-17) exhibited declines in MSCs group at 6 months compared to the placebo group (p = 0.034 and 0.033, respectively). There was no difference of incidence of AEs between the two groups.

CONCLUSION

Intravenous transplantation of HUC-MSCs is a safe and effective therapeutic approach on aging frailty. The positive outcomes observed in improving quality of life, physical performance, and reducing chronic inflammation, suggest that HUC-MSC therapy may be a promising potential treatment option for aging frailty.

TRIAL REGISTRATION

Clinicaltrial.gov; NCT04314011; https://clinicaltrials.gov/ct2/show/NCT04314011 .

Human umbilical cord-derived mesenchymal stromal cells improve myocardial fibrosis and restore miRNA-133a expression in diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a serious health-threatening complication of diabetes mellitus characterized by myocardial fibrosis and abnormal cardiac function. Human umbilical cord mesenchymal stromal cells (hUC-MSCs) are a potential therapeutic tool for DCM and myocardial fibrosis via mechanisms such as the regulation of microRNA (miRNA) expression and inflammation. It remains unclear, however, whether hUC-MSC therapy has beneficial effects on cardiac function following different durations of diabetes and which mechanistic aspects of DCM are modulated by hUC-MSC administration at different stages of its development. This study aimed to investigate the therapeutic effects of intravenous administration of hUC-MSCs on DCM following different durations of hyperglycemia in an experimental male model of diabetes and to determine the effects on expression of candidate miRNAs, target mRNA and inflammatory mediators.

METHODS

A male mouse model of diabetes was induced by multiple low-dose streptozotocin injections. The effects on severity of DCM of intravenous injections of hUC-MSCs and saline two weeks previously were compared at 10 and 18 weeks after diabetes induction. At both time-points, biochemical assays, echocardiography, histopathology, polymerase chain reaction (PCR), immunohistochemistry and enzyme-linked immunosorbent assays (ELISA) were used to analyze blood glucose, body weight, cardiac structure and function, degree of myocardial fibrosis and expression of fibrosis-related mRNA, miRNA and inflammatory mediators.

RESULTS

Saline-treated diabetic male mice had impaired cardiac function and increased cardiac fibrosis after 10 and 18 weeks of diabetes. At both time-points, cardiac dysfunction and fibrosis were improved in hUC-MSC-treated mice. Pro-fibrotic indicators (α-SMA, collagen I, collagen III, Smad3, Smad4) were reduced and anti-fibrotic mediators (FGF-1, miRNA-133a) were increased in hearts of diabetic animals receiving hUC-MSCs compared to saline. Increased blood levels of pro-inflammatory cytokines (IL-6, TNF, IL-1β) and increased cardiac expression of IL-6 were also observed in saline-treated mice and were reduced by hUC-MSCs at both time-points, but to a lesser degree at 18 weeks.

CONCLUSION

Intravenous injection of hUC-MSCs ameliorated key functional and structural features of DCM in male mice with diabetes of shorter and longer duration. Mechanistically, these effects were associated with restoration of intra-myocardial expression of miRNA-133a and its target mRNA COL1AI as well as suppression of systemic and localized inflammatory mediators.

Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

Ossification of the Posterior Longitudinal Ligament (OPLL) is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone, resulting in limited spinal mobility and nerve compression. Employing both bulk and single-cell RNA sequencing, we elucidate the molecular characteristics, cellular components, and their evolution during the OPLL process at a single-cell resolution, and validate these findings in clinical samples. This study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in vivo. Notably, our study identifies LOXL2 as a key regulator in this process. Through gain-and loss-of-function studies, we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament cells. It acts via the HIF1A pathway, promoting the secretion of downstream VEGFA and PDGF-BB. This function is not related to the enzymatic activity of LOXL2. Furthermore, we identify sorafenib, a broad-spectrum tyrosine kinase inhibitor, as an effective suppressor of LOXL2-mediated vascular morphogenesis. By disrupting the coupling between vascularization and osteogenesis, sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone mass. These findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

Pre-cultured, cell-encapsulating fibrin microbeads for the vascularization of ischemic tissues

There is a significant clinical need to develop effective vascularization strategies for tissue engineering and the treatment of ischemic pathologies. In patients afflicted with critical limb ischemia, comorbidities may limit common revascularization strategies. Cell-encapsulating modular microbeads possess a variety of advantageous properties, including the ability to support prevascularization in vitro while retaining the ability to be injected in a minimally invasive manner in vivo. Here, fibrin microbeads containing human umbilical vein endothelial cells (HUVEC) and bone marrow-derived mesenchymal stromal cells (MSC) were cultured in suspension for 3 days (D3 PC microbeads) before being implanted within intramuscular pockets in a SCID mouse model of hindlimb ischemia. By 14 days post-surgery, animals treated with D3 PC microbeads showed increased macroscopic reperfusion of ischemic foot pads and improved limb salvage compared to the cellular controls. Delivery of HUVEC and MSC via microbeads led to the formation of extensive microvascular networks throughout the implants. Engineered vessels of human origins showed evidence of inosculation with host vasculature, as indicated by erythrocytes present in hCD31+ vessels. Over time, the total number of human-derived vessels within the implant region decreased as networks remodeled and an increase in mature, pericyte-supported vascular structures was observed. Our findings highlight the potential therapeutic benefit of developing modular, prevascularized microbeads as a minimally invasive therapeutic for treating ischemic tissues.

Biotherapeutic approaches against cardio-metabolic dysfunctions based on extracellular vesicles

Among the different pathways involved in the cell-to-cell communication, extracellular vesicles (EVs) are defined as key players in the transport of different signalling molecules, such as lipids, proteins, and RNA, from the originating cells to specific target cells. The biogenesis and composition of EVs are complex and confer them a unique ability to more effectively reach tissues and cells as compared to other types of synthetic carriers. Owing to these properties, EVs have been suggested as new therapeutic tools for personalized medicine. Since cardiometabolic diseases have reached pandemic proportions, new therapies are needed to be developed. In this context, EVs appear as promising therapeutic tools against cardiometabolic disorders associated with obesity and diabetes. This review focuses on the latest research on preclinical applications of EVs for cardiometabolic diseases, and draw primarily on our experience in this area.

Large-scale bioreactor production of extracellular vesicles from mesenchymal stromal cells for treatment of acute radiation syndrome

BACKGROUND

Hematopoietic acute radiation syndrome (H-ARS) occurring after exposure to ionizing radiation damages bone marrow causing cytopenias, increasing susceptibility to infections and death. We and others have shown that cellular therapies like human mesenchymal stromal cells (MSCs), or monocytes/macrophages educated ex-vivo with extracellular vesicles (EVs) from MSCs were effective in a lethal H-ARS mouse model. However, given the complexity of generating cellular therapies and the potential risks of using allogeneic products, development of an "off-the-shelf" cell-free alternative like EVs may have utility in conditions like H-ARS that require rapid deployment of available therapeutics. The purpose of this study was to determine the feasibility of producing MSC-derived EVs at large scale using a bioreactor and assess critical quality control attributes like identity, sterility, and potency in educating monocytes and promoting survival in a lethal H-ARS mouse model.

METHODS

EVs were isolated by ultracentrifugation from unprimed and lipopolysaccharide (LPS)-primed MSCs grown at large scale using a hollow fiber bioreactor and compared to a small scale system using flasks. The physical identity of EVs included a time course assessment of particle diameter, yield, protein content and surface marker profile by flow-cytometry. Comparison of the RNA cargo in EVs was determined by RNA-seq. Capacity of EVs to generate exosome educated monocytes (EEMos) was determined by qPCR and flow cytometry, and potency was assessed in vivo using a lethal ARS model with NSG mice.

RESULTS

Physical identity of EVs at both scales were similar but yields by volume were up to 38-fold more using a large-scale bioreactor system. RNA-seq indicated that flask EVs showed upregulated let-7 family and miR-143 micro-RNAs. EEMos educated with LPS-EVs at each scale were similar, showing increased gene expression of IL-6, IDO, FGF-2, IL-7, IL-10, and IL-15 and immunophenotyping consistent with a PD-L1 high, CD16 low, and CD86 low cell surface expression. Treatment with LPS-EVs manufactured at both scales were effective in the ARS model, improving survival and clinical scores through improved hematopoietic recovery. EVs from unprimed MSCs were less effective than LPS-EVs, with flask EVs providing some improved survival while bioreactor EVs provide no survival benefit.

CONCLUSIONS

LPS-EVs as an effective treatment for H-ARS can be produced using a scale-up development manufacturing process, representing an attractive off-the-shelf, cell-free therapy.

Regenerating the ailing heart: Stem cell therapies for hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart defect (CHD) characterized by a spectrum of underdeveloped left-sided cardiac structures. It is a serious defect and warrants either 3-staged surgical palliation or a heart transplant. Despite numerous surgical advancements, long-term outcomes remain challenging and still have significant morbidity and mortality. There have been notable advancements in stem cell therapy for HLHS, including developments in diverse stem cell origins and methods of administration. Clinical trials have shown safety and potential benefits, including improved ventricular function, reduced heart failure, and fewer adverse events. Younger myocardium seems particularly receptive to stem cell signals, suggesting the importance of early intervention. This review explores the potential of emerging stem cell-based therapies as an adjunctive approach to improve the outcomes for HLHS patients.

Dual-Targeting Nanovesicles Carrying CSF1/CD47 Identified from Single-Cell Transcriptomics of Innate Immune Cells in Heart Transplant for Alleviating Acute Rejection

Although immunosuppressive drugs for targeting T cells are the standard of care in acute transplantation rejection, the role of innate immune cells should not be ignored. Here, single-cell RNA sequencing (scRNA-seq) and flow cytometry are performed to reveal the dynamic changes of innate immune cells within the acute rejection time and find a significantly-increased presence of Ly6G- Ly6C+ inflammatory macrophages and decreased presence of neutrophils among all types of immune cells. Next, to further explore potential targets regulating Ly6G- Ly6C+ inflammatory macrophages, scRNA-seq is used to analyze the reciprocal signaling of both neutrophils and macrophages, along with the surface genes of macrophages. It is found that activating colony-stimulating factor 1/ colony-stimulating factor 1 receptor (CSF1/CSF1R) andcluster of differentiation 47/signal regulatory protein α (CD47/SIRPα) signaling may serve as a strategy to relieve Ly6G- Ly6C+ inflammatory macrophage-mediated early graft rejection. To investigate this hypothesis, CSF1/CD47 dual-targeting nanovesicles (NVs) derived from IFN-γ-stimulated induced pluripotent stem cell-derived mesenchymal stem cells ( iPSC-MSCs )are designed and constructed. It is confirmed that CSF1/CD47 NVs synergistically induce the differentiation of Ly6G- Ly6C- M2 inhibitory macrophages by the CSF1/CSF1R pathway, and inhibit the phagocytosis of inflammatory macrophages and inflammatory response by the CD47/SIRPα pathway, ultimately relieving immune rejection. This study highlights the power of dual-targeting CSF1/CD47 NVs as an immunosuppressant against early innate immune responses with the potential for broad clinical applications.

Efficacy of adipose-derived mesenchymal stem cell therapy in the treatment of chronic micro- and macrovascular complications of diabetes

Diabetes mellitus is a highly prevalent disease characterized by hyperglycaemia that damages the vascular system, leading to micro- (retinopathy, neuropathy, nephropathy) and macrovascular diseases (cardiovascular disease). There are also secondary complications of diabetes (cardiomyopathy, erectile dysfunction or diabetic foot ulcers). Stem cell-based therapies have become a promising tool targeting diabetes symptoms and its chronic complications. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are of great importance because of their abundance, non-invasive isolation and no ethical limitations. Characteristics that make ADMSCs good candidates for cell-based therapy are their wide immunomodulatory properties and paracrine activities through the secretion of an array of growth factors, chemokines, cytokines, angiogenic factors and anti-apoptotic molecules. Besides, after transplantation, ADMSCs show great ex vivo expansion capacity and differentiation to other cell types, including insulin-producing cells, cardiomyocytes, chondrocytes, hepatocyte-like cells, neurons, endothelial cells, photoreceptor-like cells, or astrocytes. Preclinical studies have shown that ADMSC-based therapy effectively improved visual acuity, ameliorated polyneuropathy and foot ulceration, arrested the development and progression of diabetic kidney disease, or alleviated the diabetes-induced cardiomyocyte hypertrophy. However, despite the positive results obtained in animal models, there are still several challenges that need to be overcome before the results of preclinical studies can be translated into clinical applications. To date, there are several clinical trials or ongoing trials using ADMSCs in the treatment of diabetic complications, most of them in the treatment of diabetic foot ulcers. This narrative review summarizes the most recent outcomes on the usage of ADMSCs in the treatment of long-term complications of diabetes in both animal models and clinical trials.

Nicorandil-Pretreated Mesenchymal Stem Cell-Derived Exosomes Facilitate Cardiac Repair After Myocardial Infarction via Promoting Macrophage M2 Polarization by Targeting miR-125a-5p/TRAF6/IRF5 Signaling Pathway

Background

Exosomes derived from bone marrow mesenchymal stem cells (MSC-exo) have been considered as a promising cell-free therapeutic strategy for ischemic heart disease. Cardioprotective drug pretreatment could be an effective approach to improve the efficacy of MSC-exo. Nicorandil has long been used in clinical practice for cardioprotection. This study aimed to investigate whether the effects of exosomes derived from nicorandil pretreated MSC (MSCNIC-exo) could be enhanced in facilitating cardiac repair after acute myocardial infarction (AMI).

Methods

MSCNIC-exo and MSC-exo were collected and injected into the border zone of infarcted hearts 30 minutes after coronary ligation in rats. Macrophage polarization was detected 3 days post-infarction, cardiac function as well as histological pathology were measured on the 28th day after AMI. Macrophages were separated from the bone marrow of rats for in vitro model. Exosomal miRNA sequencing was conducted to identify differentially expressed miRNAs between MSCNIC-exo and MSC-exo. MiRNA mimics and inhibitors were transfected to MSCs or macrophages to explore the specific mechanism.

Results

Compared to MSC-exo, MSCNIC-exo showed superior therapeutic effects on cardiac functional and structural recovery after AMI and markedly elevated the ratio of CD68+ CD206+/ CD68+cells in infarcted hearts 3 days post-infarction. The notable ability of MSCNIC-exo to promote macrophage M2 polarization was also confirmed in vitro. Exosomal miRNA sequencing and both in vivo and in vitro experiments identified and verified that miR-125a-5p was an effector of the roles of MSCNIC-exo in vivo and in vitro. Furthermore, we found miR-125a-5p promoted macrophage M2 polarization by inhibiting TRAF6/IRF5 signaling pathway.

Conclusion

This study suggested that MSCNIC-exo could markedly facilitate cardiac repair post-infarction by promoting macrophage M2 polarization by upregulating miR-125a-5p targeting TRAF6/IRF5 signaling pathway, which has great potential for clinical translation.

Ultrasound-targeted microbubble destruction promotes PDGF-primed bone mesenchymal stem cell transplantation for myocardial protection in acute Myocardial Infarction in rats

BACKGROUND

Ultrasound-targeted microbubble destruction (UTMD) has emerged as a promising strategy for the targeted delivery of bone marrow mesenchymal stem cells (MSCs) to the ischemic myocardium. However, the limited migration capacity and poor survival of MSCs remains a major therapeutic barrier. The present study was performed to investigate the synergistic effect of UTMD with platelet-derived growth factor BB (PDGF-BB) on the homing of MSCs for acute myocardial infarction (AMI).

METHODS

MSCs from male donor rats were treated with PDGF-BB, and a novel microbubble formulation was prepared using a thin-film hydration method. In vivo, MSCs with or without PDGF-BB pretreatment were transplanted by UTMD after inducing AMI in experimental rats. The therapeutic efficacy of PDGF-BB-primed MSCs on myocardial apoptosis, angiogenesis, cardiac function and scar repair was estimated. The effects and molecular mechanisms of PDGF-BB on MSC migration and survival were explored in vitro.

RESULTS

The results showed that the biological effects of UTMD increased the local levels of stromal-derived factor-1 (SDF-1), which promoted the migration of transplanted MSCs to the ischemic region. Compared with UTMD alone, UTMD combined with PDGF-BB pretreatment significantly increased the cardiac homing of MSCs, which subsequently reduced myocardial apoptosis, promoted neovascularization and tissue repair, and increased cardiac function 30 days after MI. The vitro results demonstrated that PDGF-BB enhanced MSC migration and protected these cells from H2O2-induced apoptosis. Mechanistically, PDGF-BB pretreatment promoted MSC migration and inhibited H2O2-induced MSC apoptosis via activation of the phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt) pathway. Furthermore, crosstalk between PDGF-BB and stromal-derived factor-1/chemokine receptor 4 (SDF-1/CXCR4) is involved in the PI3K/AKT signaling pathway.

CONCLUSION

The present study demonstrated that UTMD combined with PDGF-BB treatment could enhance the homing ability of MSCs, thus alleviating AMI in rats. Therefore, UTMD combined with PDGF-BB pretreatment may offer exciting therapeutic opportunities for strengthening MSC therapy in ischemic diseases.

Macrophage Heterogeneity and Its Impact on Myocardial Ischemia-Reperfusion Injury: An Integrative Review

The coronary reperfusion following acute myocardial infarction can paradoxically trigger myocardial ischemia-reperfusion (IR) injury. This complex phenomenon involves the intricate interplay of different subsets of macrophages. These macrophages are crucial players in the post-infarction inflammatory response and subsequent myocardial anti-inflammatory repair. However, their diverse functions can lead to both beneficial and detrimental effects. On one hand, these macrophages play a crucial role in orchestrating the inflammatory response, aiding in the clearance of cellular debris and initiating tissue repair mechanisms. On the other hand, their excessive infiltration and activation can contribute to the perpetuation of the inflammatory cascade, leading to additional myocardial injury and adverse cardiac remodeling. Multiple mechanisms contribute to the IR injury mediated by macrophages, including oxidative stress, apoptosis, and autophagy. These processes further exacerbate the damage to the already vulnerable myocardial tissue. To address this delicate balance, therapeutic strategies aiming to target and modulate macrophage polarization and function are being explored. By fine-tuning the immune inflammatory response, such interventions hold promise in mitigating post-infarction myocardial injury and fostering a more favorable environment for myocardial healing and recovery. Through advancements in this area of research, potential anti-inflammatory interventions may pave the way for improved clinical outcomes and better management of patients after acute myocardial infarction.

Intracellular delivery of nitric oxide enhances the therapeutic efficacy of mesenchymal stem cells for myocardial infarction

Cell therapy by autologous mesenchymal stem cells (MSCs) is a clinically acceptable strategy for treating various diseases. Unfortunately, the therapeutic efficacy is largely affected by the low quality of MSCs collected from patients. Here, we showed that the gene expression of MSCs from patients with diabetes was differentially regulated compared to that of MSCs from healthy controls. Then, MSCs were genetically engineered to catalyze an NO prodrug to release NO intracellularly. Compared to extracellular NO conversion, intracellular NO delivery effectively prolonged survival and enhanced the paracrine function of MSCs, as demonstrated by in vitro and in vivo assays. The enhanced therapeutic efficacy of engineered MSCs combined with intracellular NO delivery was further confirmed in mouse and rat models of myocardial infarction, and a clinically relevant cell administration paradigm through secondary thoracotomy has been attempted.

Challenges and future scope of exosomes in the treatment of cardiovascular diseases

Exosomes are nanosized vesicles that carry biologically diverse molecules for intercellular communication. Researchers have been trying to engineer exosomes for therapeutic purposes by using different approaches to deliver biologically active molecules to the various target cells efficiently. Recent technological advances may allow the biodistribution and pharmacokinetics of exosomes to be modified to meet scientific needs with respect to specific diseases. However, it is essential to determine an exosome's optimal dosage and potential side effects before its clinical use. Significant breakthroughs have been made in recent decades concerning exosome labelling and imaging techniques. These tools provide in situ monitoring of exosome biodistribution and pharmacokinetics and pinpoint targetability. However, because exosomes are nanometres in size and vary significantly in contents, a deeper understanding is required to ensure accurate monitoring before they can be applied in clinical settings. Different research groups have established different approaches to elucidate the roles of exosomes and visualize their spatial properties. This review covers current and emerging strategies for in vivo and in vitro exosome imaging and tracking for potential studies.

The therapeutic efficacy and clinical translation of mesenchymal stem cell-derived exosomes in cardiovascular diseases

Exosomes, mainly derived from mesenchymal stem cells, provide a good reference for cardiac function repair and clinical application in cardiac and vascular diseases by regulating cardiomyocyte viability, inflammatory levels, angiogenesis, and ventricular remodeling after a heart injury. This review presents the cardioprotective efficacy of mesenchymal stem cell-originated exosomes and explores the underlying molecular mechanisms. Furthermore, we expound on several efficient approaches to transporting exosomes into the heart in clinical application and comment on the advantages and disadvantages of each method.

Roles of long non-coding RNAs in angiogenesis-related diseases: Focusing on non-neoplastic aspects

Angiogenesis is a key process in organ and tissue morphogenesis, as well as growth during human development, and is coordinated by pro- and anti-angiogenic factors. When this balance is affected, the related physiological and pathological changes lead to disease. Long non-coding RNAs (lncRNAs) are an important class of non-coding RNAs that do not encode proteins, but play a dynamic role in regulating gene expression. LncRNAs have been reported to be extensively involved in angiogenesis, particularly tumor angiogenesis. The non-tumor aspects have received relatively little attention and summary, but there is a broad space for research and exploration on lncRNA-targeted angiogenesis in this area. In this review, we focus on lncRNAs in angiogenesis-related diseases other than tumors, such as atherosclerosis, myocardial infarction, stroke, diabetic complications, hypertension, osteoporosis, dermatosis, as well as, endocrine, neurological, and other systemic disorders. Moreover, multiple cell types have been implicated in lncRNA-targeted angiogenesis, but only endothelial cells have attracted widespread attention. Thus, we explore the roles of other cells. Finally, we summarize the potential research directions in the area of lncRNAs and angiogenesis that can be undertaken by combining cutting-edge technology and interdisciplinary research, which will provide new insights into the involvement of lncRNAs in angiogenesis-related diseases.

Integrin beta 3-overexpressing mesenchymal stromal cells display enhanced homing and can reduce atherosclerotic plaque

BACKGROUND

Umbilical cord (UC) mesenchymal stem cell (MSC) transplantation is a potential therapeutic intervention for atherosclerotic vascular disease. Integrin beta 3 (ITGB3) promotes cell migration in several cell types. However, whether ITGB-modified MSCs can migrate to plaque sites in vivo and play an anti-atherosclerotic role remains unclear.

AIM

To investigate whether ITGB3-overexpressing MSCs (MSCsITGB3) would exhibit improved homing efficacy in atherosclerosis.

METHODS

UC MSCs were isolated and expanded. Lentiviral vectors encoding ITGB3 or green fluorescent protein (GFP) as control were transfected into MSCs. Sixty male apolipoprotein E-/- mice were acquired from Beijing Vital River Lab Animal Technology Co., Ltd and fed with a high-fat diet (HFD) for 12 wk to induce the formation of atherosclerotic lesions. These HFD-fed mice were randomly separated into three clusters. GFP-labeled MSCs (MSCsGFP) or MSCsITGB3 were transplanted into the mice intravenously via the tail vein. Immunofluorescence staining, Oil red O staining, histological analyses, western blotting, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction were used for the analyses.

RESULTS

ITGB3 modified MSCs successfully differentiated into the "osteocyte" and "adipocyte" phenotypes and were characterized by positive expression (> 91.3%) of CD29, CD73, and CD105 and negative expression (< 1.35%) of CD34 and Human Leukocyte Antigen-DR. In a transwell assay, MSCsITGB3 showed significantly faster migration than MSCsGFP. ITGB3 overexpression had no effects on MSC viability, differentiation, and secretion. Immunofluorescence staining revealed that ITGB3 overexpression substantially enhanced the homing of MSCs to plaque sites. Oil red O staining and histological analyses further confirmed the therapeutic effects of MSCsITGB3, significantly reducing the plaque area. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction revealed that MSCITGB3 transplantation considerably decreased the inflammatory response in pathological tissues by improving the dynamic equilibrium of pro- and anti-inflammatory cytokines.

CONCLUSION

These results showed that ITGB3 overexpression enhanced the MSC homing ability, providing a potential approach for MSC delivery to plaque sites, thereby optimizing their therapeutic effects.

Advances in the design, generation, and application of tissue-engineered myocardial equivalents

Due to the limited regenerative ability of cardiomyocytes, the disabling irreversible condition of myocardial failure can only be treated with conservative and temporary therapeutic approaches, not able to repair the damage directly, or with organ transplantation. Among the regenerative strategies, intramyocardial cell injection or intravascular cell infusion should attenuate damage to the myocardium and reduce the risk of heart failure. However, these cell delivery-based therapies suffer from significant drawbacks and have a low success rate. Indeed, cardiac tissue engineering efforts are directed to repair, replace, and regenerate native myocardial tissue function. In a regenerative strategy, biomaterials and biomimetic stimuli play a key role in promoting cell adhesion, proliferation, differentiation, and neo-tissue formation. Thus, appropriate biochemical and biophysical cues should be combined with scaffolds emulating extracellular matrix in order to support cell growth and prompt favorable cardiac microenvironment and tissue regeneration. In this review, we provide an overview of recent developments that occurred in the biomimetic design and fabrication of cardiac scaffolds and patches. Furthermore, we sift in vitro and in situ strategies in several preclinical and clinical applications. Finally, we evaluate the possible use of bioengineered cardiac tissue equivalents as in vitro models for disease studies and drug tests.

Geriatric syndromes, chronic inflammation, and advances in the management of frailty: A review with new insights

As people age, geriatric syndromes characterized by frailty significantly impact both clinical practice and public health. Aging weakens people's immune functions, leading to chronic low-grade inflammation that ultimately contributes to the development of frailty. Effectively managing geriatric syndromes and frailty can help alleviate the economic burden of an aging population. This review delves into the intricate relationship among aging, infection-induced inflammation, chronic inflammation, and frailty. In addition, it analyzes various approaches and interventions to address frailty, such as smart rehabilitation programs and stem-cell treatments, offering promising solutions in this new era. Given the importance of this topic, further research into the mechanisms of frailty is crucial. Equally essential is the devising of relevant measures to delay its onset and the formulation of comprehensive clinical, research, and public health strategies to enhance the quality of life for elderly individuals.

Mesenchymal STRO-1/STRO-3+ precursor cells for the treatment of chronic heart failure with reduced ejection fraction

The heart is susceptible to proinflammatory and profibrotic responses after myocardial injury, leading to further worsening of cardiac dysfunction. Important developments in the management of heart failure with reduced ejection fraction have reduced morbidity and mortality; however, these therapies focus on optimizing cardiac function through hemodynamic and neurohormonal pathways and not by repairing the underlying cardiac injury. The potential of cell-based therapy to reverse cardiac injury has received substantial attention. Herein are examined the phase II and III studies of bone marrow-derived mesenchymal STRO-1+ or STRO-1/STRO-3+ precursor cells in patients with ischemic and nonischemic heart failure with reduced ejection fraction, addressing the safety and efficacy of cell-based therapy throughout multiple clinical trials, the optimal dose and the steps toward revolutionizing the treatment of heart failure.

Mesenchymal Stem/Stromal Cells for Therapeutic Angiogenesis

Mesenchymal stem/stromal cells (MSCs) are known to possess medicinal properties to facilitate vascular regeneration. Recent advances in the understanding of the utilities of MSCs in physiological/pathological tissue repair and technologies in isolation, expansion, and enhancement strategies have led to the use of MSCs for vascular disease-related treatments. Various conditions, including chronic arterial occlusive disease, diabetic ulcers, and chronic wounds, cause significant morbidity in patients. Therapeutic angiogenesis by cell therapy has led to the possibilities of treatment options in promoting angiogenesis, treating chronic wounds, and improving amputation-free survival. Current perspectives on the options for the use of MSCs for therapeutic angiogenesis in vascular research and in medicine, either as a monotherapy or in combination with conventional interventions, for treating patients with peripheral artery diseases are discussed in this review.

Nanozyme-Integrated Thermoresponsive In Situ Forming Hydrogel Enhances Mesenchymal Stem Cell Viability and Paracrine Effect for Efficient Spinal Cord Repair

Mesenchymal stem cell (MSC)-based therapy has emerged as a promising strategy for the treatment of spinal cord injury (SCI). However, the hostile microenvironment of SCI, which can adversely affect the survival and paracrine effect of the implanted MSCs, severely limits the therapeutic efficacy of this approach. Here, we report on a ceria nanozyme-integrated thermoresponsive in situ forming hydrogel (CeNZ-gel) that can enable dual enhancement of MSC viability and paracrine effect, leading to highly efficient spinal cord repair. The sol-gel transition property of the CeNZ-gel at body temperature ensures uniform coverage of the hydrogel in injured spinal cord tissues. Our results demonstrate that the CeNZ-gel significantly increases the viability of transplanted MSCs in the microenvironment by attenuating oxidative stress and, more importantly, promotes the secretion of angiogenic factors from MSCs by inducing autophagy of MSCs. The synergy between the oxidative stress-relieving effect of CeNZs and the paracrine effect of MSCs accelerates angiogenesis, nerve repair, and motor function recovery after SCI, providing an efficient strategy for MSC-based SCI therapy.

Stem cell therapy for acute myocardial infarction: Mesenchymal Stem Cells and induced Pluripotent Stem Cells

INTRODUCTION

Acute myocardial infarction (AMI) remains a leading cause of death in the United States. The limited capacity of cardiomyocytes to regenerate and the restricted contractility of scar tissue after AMI are not addressed by current pharmacologic interventions. Mesenchymal stem/stromal cells (MSCs) have emerged as a promising therapeutic approach due to their low antigenicity, ease of harvesting, and efficacy and safety in preclinical and clinical studies, despite their low survival and engraftment rates. Other stem cell types, such as induced pluripotent stem cells (iPSCs) also show promise, and optimizing cardiac repair requires integrating emerging technologies and strategies.

AREAS COVERED

This review offers insights into advancing cell-based therapies for AMI, emphasizing meticulously planned trials with a standardized definition of AMI, for a bench-to-bedside approach. We critically evaluate fundamental studies and clinical trials to provide a comprehensive overview of the advances, limitations and prospects for cell-based therapy in AMI.

EXPERT OPINION

MSCs continue to show potential promise for treating AMI and its sequelae, but addressing their low survival and engraftment rates is crucial for clinical success. Integrating emerging technologies such as pluripotent stem cells and conducting well-designed trials will harness the full potential of cell-based therapy in AMI management. Collaborative efforts are vital to developing effective stem cell therapies for AMI patients.

Mechanisms of analgesic effect of mesenchymal stem cells in osteoarthritis pain

Osteoarthritis (OA) is the most common musculoskeletal disease, and it is a major cause of pain, disability and health burden. Pain is the most common and bothersome presentation of OA, but its treatment is still suboptimal, due to the short-term action of employed analgesics and their poor adverse effect profile. Due to their regenerative and anti-inflammatory properties, mesenchymal stem cells (MSCs) have been extensively investigated as a potential therapy for OA, and numerous preclinical and clinical studies found a significant improvement in joint pathology and function, pain scores and/or quality of life after administration of MSCs. Only a limited number of studies, however, addressed pain control as the primary end-point or investigated the potential mechanisms of analgesia induced by MSCs. In this paper, we review the evidence reported in literature that support the analgesic action of MSCs in OA, and we summarize the potential mechanisms of these antinociceptive effects.

Multipotent Mesenchymal Stem Cell-Based Therapies for Spinal Cord Injury: Current Progress and Future Prospects

Spinal cord injury (SCI) represents a significant medical challenge, often resulting in permanent disability and severely impacting the quality of life for affected individuals. Traditional treatment options remain limited, underscoring the need for novel therapeutic approaches. In recent years, multipotent mesenchymal stem cells (MSCs) have emerged as a promising candidate for SCI treatment due to their multifaceted regenerative capabilities. This comprehensive review synthesizes the current understanding of the molecular mechanisms underlying MSC-mediated tissue repair in SCI. Key mechanisms discussed include neuroprotection through the secretion of growth factors and cytokines, promotion of neuronal regeneration via MSC differentiation into neural cell types, angiogenesis through the release of pro-angiogenic factors, immunomodulation by modulating immune cell activity, axonal regeneration driven by neurotrophic factors, and glial scar reduction via modulation of extracellular matrix components. Additionally, the review examines the various clinical applications of MSCs in SCI treatment, such as direct cell transplantation into the injured spinal cord, tissue engineering using biomaterial scaffolds that support MSC survival and integration, and innovative cell-based therapies like MSC-derived exosomes, which possess regenerative and neuroprotective properties. As the field progresses, it is crucial to address the challenges associated with MSC-based therapies, including determining optimal sources, intervention timing, and delivery methods, as well as developing standardized protocols for MSC isolation, expansion, and characterization. Overcoming these challenges will facilitate the translation of preclinical findings into clinical practice, providing new hope and improved treatment options for individuals living with the devastating consequences of SCI.

Extracellular Vesicles Act as Carriers for Cargo Delivery and Regulate Wnt Signaling in the Hepatocellular Carcinoma Tumor Microenvironment

As the primary type of liver cancer, hepatocellular carcinoma (HCC) causes a large number of deaths every year. Despite extensive research conducted on this disease, the prognosis of HCC remains unclear. Recently, research has largely focused on extracellular vesicles (EVs), and they have been found to participate in various ways in the development of various diseases, including HCC, such as by regulating cell signaling pathways. However, recent studies have reported the mechanisms underlying the regulation of Wnt signaling by EVs in HCC, primarily focusing on the regulation of the canonical pathways. This review summarizes the current literature on the regulation of Wnt signaling by EVs in HCC and their underlying mechanisms. In addition, we also present future research directions in this field. This will deepen the understanding of HCC and provide new ideas for its treatment.

Cardiac tissue engineering for myocardial infarction treatment

Myocardial infarction is one of the major causes of morbidity and mortality worldwide. Current treatments can relieve the symptoms of myocardial ischemia but cannot repair the necrotic myocardial tissue. Novel therapeutic strategies based on cellular therapy, extracellular vesicles, non-coding RNAs and growth factors have been designed to restore cardiac function while inducing cardiomyocyte cycle re-entry, ensuring angiogenesis and cardioprotection, and preventing ventricular remodeling. However, they face low stability, cell engraftment issues or enzymatic degradation in vivo, and it is thus essential to combine them with biomaterial-based delivery systems. Microcarriers, nanocarriers, cardiac patches and injectable hydrogels have yielded promising results in preclinical studies, some of which are currently being tested in clinical trials. In this review, we cover the recent advances made in cellular and acellular therapies used for cardiac repair after MI. We present current trends in cardiac tissue engineering related to the use of microcarriers, nanocarriers, cardiac patches and injectable hydrogels as biomaterial-based delivery systems for biologics. Finally, we discuss some of the most crucial aspects that should be addressed in order to advance towards the clinical translation of cardiac tissue engineering approaches.

Hypoxia-induced CCL2/CCR2 axis in adipose-derived stem cells (ADSCs) promotes angiogenesis by human dermal microvascular endothelial cells (HDMECs) in flap tissues

Flap expansion has become an important method widely used in wound repair and organ reconstruction. However, distal skin flap ischemic necrosis remains a problematic complication. In this study, integrative bioinformatics analyses indicated the upregulation of C-C motif chemokine ligand 2 (CCL2) and C-C motif chemokine receptor 2 (CCR2) in reperfusion-exposed skin flap tissues. In adipose-derived stem cells (ADSCs, CD90-positive, CD29-positive, CD34-negative, and CD106-negative) exposed to hypoxia, HIF-1α and CCL2 levels were significantly elevated. Conditioned medium (CM) from hypoxia-stimulated ADSCs promoted HDMEC proliferation, migration, and tube formation, partially inhibited by sh-CCL2-induced CCL2 knockdown or neutralized antibody-induced CCL2 depletion in ADSCs. Consistently, CCL2, CCR2, TNF-α, TLR2, and TLR4 protein levels in HDMECs were significantly increased by hypoxia-treated ADSCs CM, and partially decreased by sh-CCL2-induced CCL2 knockdown or neutralizing antibody-induced CCL2 knockdown in ADSCs. In the flap expansion model, ADSCs transplantation significantly improved flap survival and angiogenesis by endothelial cells in flap tissues, whereas CCL2 knockdown in ADSCs partially eliminated the improvement by ADSCs transplantation; overexpression of CCL2 in ADSCs further promoted the effects of ADSCs transplantation on skin flap. In conclusion, the CCL2/CCR2 axis in ADSCs could be induced by hypoxia, promoting HDMEC proliferation, migration, and tube formation and improving flap survival and angiogenesis in flap tissues.

Promoting early neovascularization by allotransplanted adipose-derived Muse cells in an ovine model of acute myocardial infarction

BACKGROUND

Recent preclinical studies have demonstrated that bone marrow (BM)-derived Muse cells have a homing mechanism to reach damaged cardiac tissue while also being able to reduce myocardial infarct size and improve cardiac function; however, the potential of BM-Muse cells to foster new blood-vessel formation has not been fully assessed. Up to date, adipose tissue (AT)-derived Muse cells remain to be studied in acute myocardial infarction (AMI). The aim of the present study was to analyze in vitro and in vivo the neovascularization capacity of AT-Muse cells while exploring their biodistribution and differentiation potential in a translational ovine model of AMI.

METHODS AND RESULTS

AT-Muse cells were successfully isolated from ovine adipose tissue. In adult sheep, one or more diagonal branches of the left anterior descending coronary artery were permanently ligated for thirty minutes. Sheep were randomized in two groups and treated with intramyocardial injections: Vehicle (PBS, n = 4) and AT-Muse (2x107 AT-Muse cells labeled with PKH26 Red Fluorescent Dye, n = 4). Molecular characterization showed higher expression of angiogenic genes (VEGF, PGF and ANG) and increased number of tube formation in AT-Muse cells group compared to Adipose-derived mesenchymal stromal cells (ASCs) group. At 7 days post-IAM, the AT-Muse group showed significantly more arterioles and capillaries than the Vehicle group. Co-localization of PKH26+ cells with desmin, sarcomeric actin and troponin T implied the differentiation of Muse cells to a cardiac fate; moreover, PKH26+ cells also co-localized with a lectin marker, suggesting a possible differentiation to a vascular lineage.

CONCLUSION

Intramyocardially administered AT-Muse cells displayed a significant neovascularization activity and survival capacity in an ovine model of AMI.