Exosomes from Human Umbilical Vein Endothelial Cells Ameliorate Ischemic Injuries by Suppressing the RNA Component of Mitochondrial RNA-processing Endoribonuclease via the Induction of miR-206/miR-1-3p Levels

Extracellular vesicles for delivering therapeutic agents in ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is marked by the restriction and subsequent restoration of blood supply to an organ. This process can exacerbate the initial tissue damage, leading to further disorders, disability, and even death. Extracellular vesicles (EVs) are crucial in cell communication by releasing cargo that regulates the physiological state of recipient cells. The development of EVs presents a novel avenue for delivering therapeutic agents in I/R therapy. The therapeutic potential of EVs derived from stem cells, endothelial cells, and plasma in I/R injury has been actively investigated. Therefore, this review aims to provide an overview of the pathological process of I/R injury and the biophysical properties of EVs. We noted that EVs serve as nontoxic, flexible, and multifunctional carriers for delivering therapeutic agents capable of intervening in I/R injury progression. The therapeutic efficacy of EVs can be enhanced through various engineering strategies. Improving the tropism of EVs via surface modification and modulating their contents via preconditioning are widely investigated in preclinical studies. Finally, we summarize the challenges in the production and delivery of EV-based therapy in I/R injury and discuss how it can advance. This review will encourage further exploration in developing efficient EV-based delivery systems for I/R treatment.

A systematic review of exosomes in remote ischemic conditioning

BACKGROUND

Remote ischemic conditioning (RIC) is considered a promising non-pharmacological therapeutic strategy to mitigate ischemic injury. Although the precise mechanisms of RIC's protective effects remain elusive, existing data suggest that exosomes contribute significantly to these processes through cell-to-cell communication OBJECTIVE: This review aims to elucidate the role of exosomes in RIC-mediated multi-organ protection.

METHODS

We systematically searched multiple databases through October 2023 for preclinical studies evaluating the effect of exosomes in ischemic models using RIC procedures. Key outcomes, such as improved organ function and reduced infarct size, were recorded. Articles were selected and data were extracted by independent pairs of reviewers.

FINDINGS

A total of 16 relevant studies were identified in this review, showing that circulating exosomes derived from the plasma of RIC-treated animals exhibited protective effects akin to those of the RIC procedure itself. Exosome concentrations were measured in eight studies, six of which reported significant increases in the RIC group. Additional findings indicated that RIC might primarily modulate the expression of miRNAs and bioactive molecules delivered by exosomes, rather than directly altering circulating exosome levels. Notably, the expression of 11 distinct exosomal miRNAs was altered after RIC intervention, potentially involving multiple pathways.

CONCLUSION

Exosomes appear to play a pivotal role in the protective effects induced by RIC. Clarifying their function in RIC under different pathological situations represents a grand challenge for future research.

Endothelial cells-derived exosomes-based hydrogel improved tendinous repair via anti-inflammatory and tissue regeneration-promoting properties

Tendon injuries are common orthopedic ailments with a challenging healing trajectory, especially in cases like the Achilles tendon afflictions. The healing trajectory of tendon injuries is often suboptimal, leading to scar formation and functional impairment due to the inherent low metabolic activity and vascularization of tendon tissue. As pressing is needed for effective interventions, efforts are made to explore biomaterials to augment tendon healing. However, tissue engineering approaches face hurdles in optimizing tissue scaffolds and nanomedical strategies. To navigate these challenges, an injectable hydrogel amalgamated with human umbilical vein endothelial cells-derived exosomes (HUVECs-Exos) was prepared and named H-Exos-gel in this study, aiming to enhance tendon repair. In our research involving a model of Achilles tendon injuries in 60 rats, we investigated the efficacy of H-Exos-gel through histological assessments performed at 2 and 4 weeks and behavioral assessments conducted at the 4-week mark revealed its ability to enhance the Achilles tendon's mechanical strength, regulate inflammation and facilitate tendon regeneration and functional recovery. Mechanically, the H-Exos-gel modulated the cellular behaviors of macrophages and tendon-derived stem cells (TDSCs) by inhibiting inflammation-related pathways and promoting proliferation-related pathways. Our findings delineate that the H-Exos-gel epitomizes a viable bioactive medium for tendon healing, heralding a promising avenue for the clinical amelioration of tendon injuries.

Apoptotic Extracellular Vesicles Derived from Human Umbilical Vein Endothelial Cells Promote Skin Repair by Enhancing Angiogenesis: From Death to Regeneration

Purpose

The promotion of angiogenesis is an effective strategy for skin wound repair. While the transplantation of endothelial cells has shown promise in vascularization, the underlying mechanism remains unclear. Recent studies have suggested that transplanted cells undergo apoptosis in a short period and release apoptotic extracellular vesicles (ApoEVs) that may have therapeutic potential.

Methods

In this study, we isolated ApoEVs from human umbilical vein endothelial cells (HUVECs) and characterized their properties. In vitro, we assessed the effects of ApoEVs on the proliferation, migration, and differentiation of endothelial cells and fibroblasts. In vivo, we investigated the therapeutic role of ApoEVs-AT in full-thickness skin wounds, evaluating wound closure rate, re-epithelialization, granulation tissue formation, vascularization, scar area, and collagen 3(Col3)/collagen 1(Col 1) ratio.

Results

ApoEVs derived from HUVECs displayed typical characteristics. In vitro, ApoEVs significantly enhanced the proliferation, migration, tube formation, and expression of angiogenic-related genes in endothelial cells and slightly promoted the proliferation and migration of fibroblasts. In vivo, ApoEVs improved the wound closure rate, re-epithelialization, the formation of granulation tissue, and vascularization. Besides, ApoEVs reduced scar formation, accompanied by an increase in the Col 3/ Col 1 ratio.

Conclusion

Given their abundant source and effectiveness, this study provided a novel approach for angiogenesis in tissue regeneration and deepened the understanding of from death to regeneration.

The Truth Is Out There: Biological Features and Clinical Indications of Extracellular Vesicles from Human Perinatal Stem Cells

The potential of perinatal tissues to provide cellular populations to be used in different applications of regenerative medicine is well established. Recently, the efforts of researchers are being addressed regarding the evaluation of cell products (secreted molecules or extracellular vesicles, EVs) to be used as an alternative to cellular infusion. The data regarding the effective recapitulation of most perinatal cells' properties by their secreted complement point in this direction. EVs secreted from perinatal cells exhibit key therapeutic effects such as tissue repair and regeneration, the suppression of inflammatory responses, immune system modulation, and a variety of other functions. Although the properties of EVs from perinatal derivatives and their significant potential for therapeutic success are amply recognized, several challenges still remain that need to be addressed. In the present review, we provide an up-to-date analysis of the most recent results in the field, which can be addressed in future research in order to overcome the challenges that are still present in the characterization and utilization of the secreted complement of perinatal cells and, in particular, mesenchymal stromal cells.

Cardiosome-mediated protection in myocardial ischemia

Cardiosomes, exosomes released in cardiospheres by cardiomyocytes and progenitor cells, communicate locally and at a distance from different tissues, promoting beneficial cellular changes. For example, miRNAs have emerged as regulators of intercellular communication via transport by extracellular vesicles in general and cardiosomes specifically. Although cardiosomes are considered biomarkers owing to their immense biomedical application in various clinical fields, their role in cardiovascular diseases remains unclear. This mini-review examines the experimental and clinical evidence for cardiosomes as non-invasive diagnostic, treatment and prognostic tools in acute myocardial infarction, the novelty of which is often lost in medical practice. In addition, we discuss the potential role of cardiosomes in physiologic mechanisms and cell signaling in cardiac conditioning strategies against reperfusion injury.

Exosomes as biomarkers and therapeutic measures for ischemic stroke

Ischemic stroke (IS) is the leading cause of long-term disability in the world and characterized by high morbidity, recurrence, complications, and mortality. Due to the lack of early diagnostic indicators, limited therapeutic measures and inadequate prognostic indicators, the diagnosis and treatment of IS remains a particular challenge at present. It has recently been reported that exosomes (EXOs) play a significant role in the pathogenesis and treatment of IS. The purpose of this paper is to probe the role of EXOs in diagnostic biomarkers and therapeutic measures for IS and to provide innovative ideas for improving the prognosis of IS.

Role of Circulating Exosomes in Cerebrovascular Diseases: A Comprehensive Review

Exosomes are lipid bilayer vesicles that contain multiple macromolecules secreted by the parent cells and play a vital role in intercellular communication. In recent years, the function of exosomes in cerebrovascular diseases (CVDs) has been intensively studied. Herein, we briefly review the current understanding of exosomes in CVDs. We discuss their role in the pathophysiology of the diseases and the value of the exosomes for clinical applications as biomarkers and potential therapies.

Analysis of the Research Hotspot of Exosomes in Cardiovascular Disease: A Bibliometric-based Literature Review

OBJECTIVE

To investigate the current status and development trend of research on exosomes in cardiovascular disease (CVD) using bibliometric analysis and to elucidate trending research topics.

METHODS

Research articles on exosomes in CVD published up to April 2022 were retrieved from the Web of Science database. Data were organized using Microsoft Office Excel 2019. CiteSpace 6.1 and VOSviewer 1.6.18 were used for bibliometric analysis and result visualization.

RESULTS

Overall, 256 original research publications containing 190 fundamental research publications and 66 clinical research publications were included. "Extracellular vesicle" was the most frequent research keyword, followed by "microrna," "apoptosis," and "angiogenesis." Most publications were from China (187, 73.05%), followed by the United States (57, 22.27%), the United Kingdom (7, 2.73%), and Japan (7, 2.73%). A systematic review of the publications revealed that myocardial infarction and stroke were the most popular topics and that exosomes and their contents, such as microRNAs (miRNAs), play positive roles in neuroprotection, inhibition of autophagy and apoptosis, promotion of angiogenesis, and protection of cardiomyocytes.

CONCLUSION

Research on exosomes in CVD has attracted considerable attention, with China having the most published studies. Fundamental research has focused on CVD pathogenesis; exosomes regulate the progression of CVD through biological processes, such as the inflammatory response, autophagy, and apoptosis. Clinical research has focused on biomarkers for CVD; studies on using miRNAs in exosomes as disease markers for diagnosis could become a future trend.

Mesenchymal stem cell therapy for ischemic stroke: Novel insight into the crosstalk with immune cells

Stroke, a cerebrovascular accident, is prevalent and the second highest cause of death globally across patient populations; it is as a significant cause of morbidity and mortality. Mesenchymal stem cell (MSC) transplantation is emerging as a promising treatment for alleviating neurological deficits, as indicated by a great number of animal and clinical studies. The potential of regulating the immune system is currently being explored as a therapeutic target after ischemic stroke. This study will discuss recent evidence that MSCs can harness the immune system by interacting with immune cells to boost neurologic recovery effectively. Moreover, a notion will be given to MSCs participating in multiple pathological processes, such as increasing cell survival angiogenesis and suppressing cell apoptosis and autophagy in several phases of ischemic stroke, consequently promoting neurological function recovery. We will conclude the review by highlighting the clinical opportunities for MSCs by reviewing the safety, feasibility, and efficacy of MSCs therapy.

Bone marrow mesenchymal stem cell-derived exosomes carrying long noncoding RNA ZFAS1 alleviate oxidative stress and inflammation in ischemic stroke by inhibiting microRNA-15a-5p

BACKGROUND/AIM

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes can prevent oxidative stress and inflammation in cerebral ischemia-reperfusion injury. This study intended to assess influences of BMSC-released exosomes on oxidative stress and inflammation following ischemic stroke.

METHODS

In vitro and in vivo models were developed using oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion (MCAO), respectively. After exosome isolation, co-culture experiments of BMSCs or BMSC-derived exosomes and OGD/R-treated BV-2 cells were implemented to evaluate the impacts of BMSCs or BMSC-secreted exosomes on proliferation, inflammation, oxidative stress, and apoptosis. The gain-of-function experiments of ZFAS1 or microRNA (miR)-15a-5p were conducted to investigate the associated mechanisms. Besides, MCAO mice were injected with exosomes from BMSCs overexpressing ZFAS1 for in vivo verification. The binding of ZFAS1 to miR-15a-5p was assessed through dual-luciferase reporter gene assay.

RESULTS

Co-culture with BMSCs accelerated proliferation and downregulated IL-1β, IL-6, and TNF-α in OGD/R-exposed BV-2 cells, accompanied by increased SOD level and decreased MDA level and apoptosis, all of which were nullified by inhibiting exosome secretion. Mechanistically, ZFAS1 bound to miR-15a-5p to negatively orchestrate its expression. In addition, BMSC-released exosomes or BMSC-secreted exosomal ZFAS1 augmented proliferation but reduced oxidative stress, apoptosis, and inflammation in OGD/R-exposed BV-2 cells, whereas these impacts of BMSC-released exosomal ZFAS1 were nullified by overexpressing miR-15a-5p. Moreover, BMSC-derived exosomal ZFAS1 diminished MCAO-induced oxidative stress, cerebral infarction, and inflammation in mice.

CONCLUSIONS

Conclusively, BMSC-released exosomes might carry long noncoding RNA ZFAS1 to curb oxidative stress and inflammation related to ischemic stroke, which was possibly realized through miR-15a-5p inhibition.

Small extracellular vesicles of hypoxic endothelial cells regulate the therapeutic potential of adipose-derived mesenchymal stem cells via miR-486-5p/PTEN in a limb ischemia model

Background

Patients with critical limb ischemia (CLI) are at great risk of major amputation and cardiovascular events. Adipose-derived mesenchymal stem cell (ADSC) therapy is a promising therapeutic strategy for CLI, but the poor engraftment and insufficient angiogenic ability of ADSCs limit their regenerative potential. Herein, we explored the potential of human umbilical vein endothelial cells (HUVECs)-derived small extracellular vesicles (sEVs) for enhancing the therapeutic efficacy of ADSCs in CLI.

Results

sEVs derived from hypoxic HUVECs enhanced the resistance of ADSCs to reactive oxygen species (ROS) and further improved the proangiogenic ability of ADSCs in vitro. We found that the hypoxic environment altered the composition of sEVs from HUVECs and that hypoxia increased the level of miR-486-5p in sEVs. Compared to normoxic sEVs (nsEVs), hypoxic sEVs (hsEVs) of HUVECs significantly downregulated the phosphatase and tensin homolog (PTEN) via direct targeting of miR-486-5p, therefore activating the AKT/MTOR/HIF-1α pathway and influencing the survival and pro-angiogenesis ability of ADSCs. In a hindlimb ischemia model, we discovered that hsEVs-primed ADSCs exhibited superior cell engraftment, and resulted in better angiogenesis and tissue repair.

Conclusion

hsEVs could be used as a therapeutic booster to improve the curative potential of ADSCs in a limb ischemia model. This finding offers new insight for CLI treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01632-1.

A Novel Perspective on Ischemic Stroke: A Review of Exosome and Noncoding RNA Studies

Ischemic stroke is a life-threatening condition that also frequently results in long-term disability. Currently, intravenous thrombolysis with tissue plasminogen activator and mechanical thrombectomy is the most popular treatment. However, the narrow time window and related complications limit the treatment benefits. Exosomes have recently emerged as ideal therapeutic candidates for ischemic stroke with the ability to pass through the blood_brain barrier and mediate intercellular communication, in addition, exosomes and their contents can be bioengineered to implement targeted delivery. In the last two decades, exosomes and exosomal noncoding RNAs have been found to be involved in the pathophysiological progression of ischemic stroke, including atherosclerosis, apoptosis, inflammation, oxidative stress, and neurovascular remodeling. In this review, we describe the latest progress regarding the role of exosomal long noncoding RNAs and circular RNAs in the occurrence, progression, and recovery of ischemic stroke. Exploration of exosomal noncoding RNAs and their correlated effects in ischemic stroke may facilitate accurate diagnosis, and they may serve as new therapeutic targets for the disease.

Exosomes Derived From Mesenchymal Stem Cells: Novel Effects in the Treatment of Ischemic Stroke

Ischemic stroke is defined as an infarction in the brain, caused by impaired cerebral blood supply, leading to local brain tissue ischemia, hypoxic necrosis, and corresponding neurological deficits. At present, revascularization strategies in patients with acute ischemic stroke include intravenous thrombolysis and mechanical endovascular treatment. However, due to the short treatment time window (<4.5 h) and method restrictions, clinical research is focused on new methods to treat ischemic stroke. Exosomes are nano-sized biovesicles produced in the endosomal compartment of most eukaryotic cells, containing DNA, complex RNA, and protein (30-150 nm). They are released into surrounding extracellular fluid upon fusion between multivesicular bodies and the plasma membrane. Exosomes have the characteristics of low immunogenicity, good innate stability, high transmission efficiency, and the ability to cross the blood-brain barrier, making them potential therapeutic modalities for the treatment of ischemic stroke. The seed sequence of miRNA secreted by exosomes is base-paired with complementary mRNA to improve the microenvironment of ischemic tissue, thereby regulating downstream signal transduction activities. With exosome research still in the theoretical and experimental stages, this review aims to shed light on the potential of exosomes derived from mesenchymal stem cells in the treatment of ischemic stroke.

Human umbilical vein endothelial cells-derived exosomes enhance cardiac function after acute myocardial infarction by activating the PI3K/AKT signaling pathway

Currently, acute myocardial infarction (AMI) is one of the leading causes of human health issues worldwide. The sudden and continuous occlusion of the coronary artery results in myocardial hypoxic-ischemic necrosis, which is accompanied by inflammatory infiltration and fibrosis, leading to pathological cardiac remodeling. Exosome-based therapy is a promising cell-free approach for repairing the ischemic myocardium. This study aimed to explore the effects and mechanism of human umbilical vein endothelial cells (HUVECs)-derived exosomes on AMI. The results indicated that the localized injection of HUVECs-derived exosomes in the infarcted area could significantly improve cardiac function in AMI mouse models. It could also ameliorate myocardial fibrosis and decrease infarct size after AMI. Additionally, HUVECs-derived exosomes had cardioprotective effects on the H9C2 cells in hypoxic culture conditions, including increased cell viability and decreased lactate dehydrogenase (LDH) release. In both the in-vivo and in-vitro experiments, HUVECs-derived exosomes could effectively inhibit cardiomyocyte apoptosis. The low expression levels of Bcl-2–associated X protein (Bax) and cleaved caspase-3, high expression levels of B-cell lymphoma 2 (Bcl-2), phosphorylated phosphatidylinositol 3-kinase (p-PI3K), and phosphorylated protein kinase B (p-AKT) were detected in AMI mouse models treated with HUVECs-derived exosomes in-vivo. In conclusion, HUVECs-derived exosomes effectively enhanced cardiac function after AMI and inhibited cardiomyocyte apoptosis, which might be regulated through the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT) signaling pathway.