Schwann cells are essential for the maintenance and function of motor neurons, axonal networks, and the neuromuscular junction. In amyotrophic lateral sclerosis, where motor neuron function is progressively lost, Schwann cell function may also be impaired. Recently, important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been reported. This case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles, marking, to our knowledge, the first instance of such treatment. An 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral sclerosis. After initial diagnosis, the patient underwent a combination of generic riluzole, sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis, and taurursodiol. The patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron function. We confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired (senescent) and that exposure of the patient's Schwann cells to allogeneic Schwann cell-derived exosomal vesicles, cultured expanded from a cadaver donor improved their growth capacity in vitro. After a period of observation lasting 10 weeks, during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored, the patient received weekly consecutive infusions of 1.54 × 10 12 (×2), and then consecutive infusions of 7.5 × 10 12 (×6) allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco's phosphate-buffered saline. None of the infusions were associated with adverse events such as infusion reactions (allergic or otherwise) or changes in vital signs. Clinical lab serum neurofilament and cytokine levels measured prior to each infusion varied somewhat without a clear trend. A more sensitive in-house assay suggested possible inflammasome activation during the disease course. A trend for clinical stabilization was observed during the infusion period. Our study provides a novel approach to address impaired Schwann cells and possibly motor neuron function in patients with amyotrophic lateral sclerosis using allogeneic Schwann cell-derived exosomal vesicles. Initial findings suggest that this approach is safe.

The regenerative properties of exosomes make them especially appealing to treat skin and hair diseases. Preclinical studies suggest that exosomes may fuel hair growth by stimulating dermal papilla cells, activating hair follicle stem cells, and promoting angiogenesis. However, very limited data are available on the safety and efficacy of exosome use in human subjects.

To review the published literature on exosome use in human subjects with a focus on safety and the challenges facing clinical implementation in the treatment of androgenetic and nonscarring alopecias.

A review was conducted of PubMed, EMBASE, and Cochrane databases and included 48 studies. Twenty-five studies were clinical trials, 14 case reports, 4 case series, 1 retrospective review, and 4 conference abstracts.

Nine clinical studies were found relevant to alopecia. One hundred twenty-five patients received an exosome treatment for hair loss. Side effects were rare. However, in the broader field of dermatology, at least 10 serious adverse events have been reported.

Although exosomes have many promising therapeutic applications, there is demand for larger well-designed clinical trials with extended follow-up periods to prove efficacy and a need for consistent manufacturing standards and regulatory oversight to ensure product safety.

Cell membrane coating has emerged as a promising strategy for the surface modification of biomaterials with biological membranes, serving as a cloak that can carry more functions. The cloaked biomaterials inherit diverse intrinsic biofunctions derived from different cell sources, including enhanced biocompatibility, immunity evasion, specific targeting capacity, and immune regulation of the regenerative microenvironment. The intrinsic characteristics of biomimicry and biointerfacing have demonstrated the versatility of cell membrane coating technology on a variety of biomaterials, thus, furthering the research into a wide range of biomedical applications and clinical translation. Here, the preparation of cell membrane coatings is emphasized, and different sizes of coated biomaterials from nanoscale to macroscale as well as the engineering strategies to introduce additional biofunctions are summarized. Subsequently, the utilization of biomimetic membrane-cloaked biomaterials in biomedical applications is discussed, including drug delivery, imaging and phototherapy, cancer immunotherapy, anti-infection and detoxification, and implant modification. In conclusion, the latest advancements in clinical and preclinical studies, along with the multiple benefits of cell membrane-coated nanoparticles (NPs) in biomimetic systems, are elucidated.

Exosomes are tiny extracellular vesicles that are essential for intercellular communication and have shown great promise in the detection and treatment of disease. They are especially useful in the treatment of cancer, cardiovascular conditions, and neurological diseases because of their capacity to transport bioactive substances including proteins, lipids, and nucleic acids. Because of their low immunogenicity, ability to traverse biological barriers, and biocompatibility, exosome-based medicines have benefits over conventional treatments. Large-scale production, standardization of separation methods, possible immunological reactions, and worries about unforeseen biological effects are some of the obstacles that still need to be overcome. Furthermore, there are major barriers to the clinical use of exosomes due to their complex cargo sorting mechanisms and heterogeneity. Future studies should concentrate on enhancing separation and purification procedures, optimizing exosome engineering techniques, and creating plans to reduce immune system modifications. This review examines the most recent developments in exosome-based diagnostics and treatments, identifies current issues, and suggests ways to improve their clinical translation in the future.

Extracellular vesicles (EVs) derived from regenerative mesenchymal stem cells might safely treat traumatic brain injury (TBI). We evaluated the safety and efficacy of a human bone marrow derived mesenchymal stem cell EVs (hBM-MSC EV) investigational product (IP) in a patient with severe TBI.

A single case study employing an IP with a strong safety profile in over 200 patients.

The patient was dosed intravenously three times/week in the first week of six successive months. Functional Independence Measure (FIM) and Functional Assessment Measure (FAM) were performed to quantify effects. Safety monitoring was performed every week for nine months.

No adverse events occurred. Within eight weeks FIM and FAM scores improved by 48-55% and were sustained for the entire 36 weeks. All specific outcome items assessed by FIM and FAM that were initially low showed sustained improvements ranging from 41% to 233%, with the greatest improvements seen in locomotion, mobility and cognitive function.

After moderate improvement with conventional therapy, the substantial improvement observed following introduction of the IP suggests that hBM-MSC EVs may offer a novel and safe means to improve TBI patient outcomes. Appropriate randomized, controlled clinical trials to conclusively evaluate this therapeutic option are indicated.

Traditional drug therapies suffer from problems such as easy drug degradation, side effects, and treatment resistance. Traditional disease diagnosis also suffers from high error rates and late diagnosis. Extracellular vesicles (EVs) are nanoscale spherical lipid bilayer vesicles secreted by cells that carry various biologically active components and are integral to intercellular communication. EVs can be found in different body fluids and may reflect the state of the parental cells, making them ideal noninvasive biomarkers for disease-specific diagnosis. The multifaceted characteristics of EVs render them optimal candidates for drug delivery vehicles, with evidence suggesting their efficacy in the treatment of various ailments. However, poor stability and easy degradation of natural EVs have affected their applications. To solve the problems of poor stability and easy degradation of natural EVs, they can be engineered and modified to obtain more stable and multifunctional EVs. In this study, we review the shortcomings of traditional drug delivery methods and describe how to modify EVs to form engineered EVs to improve their utilization. An innovative stimulus-responsive drug delivery system for EVs has also been proposed. We also summarize the current applications and research status of EVs in the diagnosis and treatment of different systemic diseases, and look forward to future research directions, providing research ideas for scholars.

In this article, we revisit an article, which specifically focuses on the utilization of exosomes derived from human bone marrow mesenchymal stem cells (MSCs) for targeted delivery of gemcitabine in pancreatic cancer treatment. The experimental results demonstrated that the exosome-based drug delivery system derived from MSCs significantly augmented apoptosis in pancreatic cancer cells. The biocompatibility, targeting specificity, and low immunogenicity of exosomes render them as optimal carriers for drug delivery, enabling precise administration of therapeutics to diseased tissues while mitigating adverse effects, thereby achieving targeted treatment of cancer cells and significantly enhancing anti-tumor efficacy. However, the clinical application of exosome drug delivery platforms in oncology still presents challenges, necessitating further optimization to ensure their stability and efficacy. This study focuses on elucidating the advantages of exosomes as a drug delivery platform, exploring the utilization of MSC-derived exosomes in oncology therapy, and discussing their potential and future directions in cancer treatment.

The potential of the cell lysate, secretome, and extracellular vesicles (EVs) of mesenchymal stem cells (MSCs) to modulate the immune response and promote tissue regeneration has positioned them as a promising option for cell-free therapy. Currently, many clinical trials in stem cells-derived EVs and secretome are in progress various diseases and sometimes the results are failing. The major challenge on this roadmap is the lack of a standard extraction method for exosome, secretome, and lysate. The most optimal method for obtaining the secretome of MSCs for clinical utilization involves a comprehensive approach that includes non-destructive collection methods, time optimization, multiple collection rounds, optimization of culture conditions, and quality control measures. Further research and clinical studies are warranted to validate and refine these methods for safe and effective utilization of the MSC exosome, secretome, and lysate in various clinical applications. To address these challenges, it is imperative to establish a standardized and unified methodology to ensure reliable evaluation of these extractions in clinical trials. This review seeks to outline the pros and cons of methods for the preparation of MSCs-derived exosome, and secretome/lysate, and comparative analysis of their therapeutic potential.

Exosomes (Exos) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) hold great potential for treating bronchopulmonary dysplasia (BPD); however, safety concerns and effects of intranasal administration remain unexplored. This study aimed to explore the safety of hUC-MSCs and Exos and to investigate the efficacy and bio-distribution of repeated intranasal Exos administration in neonatal BPD models.

Characteristics of hUC-MSCs and Exos were analyzed. A subcutaneous tumor formation assay using a single dose of hUC-MSCs or Exos was conducted in Crl:NU-Foxn1nu mice. Vital signs, biochemical indices, pathological alterations, and 18F-FDG microPET/CT analysis were examined. Pulmonary pathology, three-dimensional reconstructions, ultrastructural structures, in vivo and ex vivo bio-distribution imaging analyses, enzyme-linked immunoassay assays, and reverse transcription-quantitative polymerase chain reaction analyses of lung tissues were all documented following intranasal Exos administration.

Characteristics of hUC-MSCs and Exos satisfied specifications. Crl:NU-Foxn1nu mice did not exhibit overt toxicity or carcinogenicity following a single dose of hUC-MSCs or Exos after 60 days of observation. Repeated intranasal Exos administration effectively alleviated pathological injuries, restored pulmonary ventilation in three-dimensional reconstruction, and recovered endothelial cell layer integrity in ultrastructural analysis. Exos steadily accumulated in lung tissues from postnatal day 1 to 14. Exos also interrupted the epithelial-mesenchymal transition and inflammation reactions in BPD models.

As a nanoscale, non-cellular therapy, intranasal administration of Exos was an effective, noninvasive treatment for BPD. This approach was free from toxic, tumorigenic risks and repaired alveolar damage while interrupting epithelial-mesenchymal transition and inflammation in neonatal mice with BPD.

Batch-to-batch reproducibility and robust quality assessment are crucial for producing cell-free biologics, such as conditioned medium (CM) derived from mesenchymal stem/stromal cells (MSCs). This study investigated the effects of freezing CM at -80 °C prior to concentration, a step that could occur in large scale pipelines, compared to freshly processed CM. Quality assessment included total protein quantification; extracellular vesicle evaluation using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and cytofluorimetry; and biochemical analysis using Raman spectroscopy. The freezing process resulted in a 34% reduction in total protein content, as confirmed for selected bioactive mediators, and significant depletion of specific particle types, particularly larger ones. Interestingly, the total particle concentration and polydispersity remained stable. Alterations in Raman spectra highlighted changes in protein, lipid, and nucleic acid content. These findings demonstrate that even routine steps like freezing can alter CM composition, likely due to temperature-induced structural changes in biological molecules. Careful consideration of pre- and intra-processing handling temperatures is critical for preserving the integrity of CM and ensuring consistent quality. This study emphasizes the importance of refining manufacturing protocols in the production of cell-free biologics.

Premature ovarian insufficiency (POI) presents a multifaceted challenge with limited treatment options. This study explored the therapeutic potential of exosome-based interventions for chemotherapy-induced POI.

Adapted exosomes were engineered from umbilical cord mesenchymal stem cells (UC-MSCs) under a specific co-culture system and used for treating in vitro and in vivo models of chemotherapy-induced premature ovarian insufficiency.

In vitro models revealed the significant impact of adapted exosomes, which promoted granulosa cell proliferation, decrease apoptosis, and enhanced ovarian functional markers. The findings in an in vivo chemotherapy-induced POI mouse model indicated the restoration of ovarian morphology, follicle numbers, and fertility in both the naïve and adapted exosome-treated groups. Notably, the adapted exosome group demonstrated a heightened pregnancy rate, increased numbers of primary follicles, and a significant reduction in ovarian apoptosis. MiRNA profiling revealed distinctive cargo in the adapted exosomes, among which miR-20b-5p played a pivotal role in regulating apoptosis and inflammation; this finding is especially important given that apoptosis is one of the primary complications of chemotherapy-induced POI. Furthermore, cells treated with adapted exosomes demonstrated significant overexpression of miR-20b-5p, resulting in decreased PTEN expression and the activation of the PI3K-AKT pathway-a crucial mechanism in mitigating chemotherapy-induced POI.

This study introduces an exosome-based therapeutic approach, emphasizing the importance of exosome cargo composition in treating disorders. Further investigation into the identified miRNA profile in adapted exosomes is necessary to clarify the underlying mechanisms, potentially leading to the development of a new treatment for clinical premature ovarian insufficiency.

Enhancing protective immunity in the respiratory tract is crucial to combat influenza infection and transmission. Developing mucosal universal influenza vaccines requires effective delivery platforms to overcome the respiratory mucosal barrier and stimulate appropriate innate immune reactions, thereby bridging adaptive immune responses with minimal necessary inflammation. Meanwhile, the vaccine platforms must be biocompatible. This study employed cell-derived extracellular vesicles (EVs) as a mucosal universal influenza vaccine platform. By conjugating influenza hemagglutinin (HA) onto EV surfaces through HA-receptor interaction, we achieved an upside-down (inverted) influenza HA configuration that exposed the conserved HA stalk region while partially hiding the globular head domain. Intranasal immunization with the resulting EVs induced robust HA stalk- and virus-specific serum antibody and mucosal immune responses in mice, protecting against heterologous virus infection. Notably, EVs derived from the lung epithelial cell line A549 induced superior cross-reactive antibodies and enhanced protection upon intranasal immunization. EVs conjugating multivalent HA elicited broadly cross-reactive antibody and cellular responses against different influenza strains. Our results demonstrated that EVs conjugating multiple inverted HAs represented an effective strategy for developing a mucosal universal influenza vaccine.

The global pandemic of coronavirus disease 2019 (COVID-19) represented a major public health concern. Growing evidence shows that plasma of COVID-19 patients contains large numbers of circulating extracellular vesicles (cEVs) that correlate with disease severity and recovery. In this study, we sought to characterize the longitudinal cEV signature in critically ill COVID-19 patients during hospitalization and its relation to mortality risk.

cEVs were quantitatively and phenotypically analysed in hospitalized non-surviving COVID-19 patients at baseline (n = 42) and before exitus (n = 40) and in 40 healthy volunteers as a reference group by high sensitivity nano flow cytometry using specific markers for parental cell sources and activation.

Levels of cEV subtypes differed between patients with severe COVID-19 and healthy subjects, specifically those from platelets and endothelial, inflammatory and viral infected cells, which associate to high mortality risk. In the longitudinal analysis from baseline to the time point immediately preceding death, no changes were found for platelet, pan-leukocyte, and lung epithelial cell-shed cEVs, while endothelial cell releases of EVs (eEVs) significantly differed. Vascular endothelial growth factor receptor 2-positive eEVs were significantly increased before death compared to admission whereas endoglin and E-selectin-containing eEVs did not change. Conversely, lymphocyte (ℓEV), monocyte, macrophage, pericyte and progenitor cell-derived cEVs displayed significant reductions before exitus. Noteworthy, levels of CD45+/CD3+-ℓEVs were significantly associated to the patient's survival time.

An evolving cEV profile able to discriminate prompt risk of death during hospitalization has been defined suggesting a role for circulating and vascular cell-derived EVs in COVID-19 pathogenesis.

Psoriasis is a chronic inflammatory dermatosis driven by excessive activation of the immune system. Recent studies have demonstrated the therapeutic potential of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) to psoriasis because of their immunomodulation functions. Yet, the outcome of MSC-EVs alone is still unsatisfactory and the underlying mechanisms are also unclear. Here, it is uncovered that arginase1 (Arg1)/polyamine is overexpressed in psoriasis patients and murine, inducing the in-situ accumulation of self-antigens. Engineered nor@MSC-EVs are fabricated by loading Arg1 inhibitor nor-NOHA into MSC-EVs for studying the therapeutic effect and mechanism of psoriasis. The nor@MSC-EVs exhibited profound suppression of the NF-κB signaling pathway by targeting Arg1/polyamine-mediated DCs/Th17 axis through scavenging self-antigens, resulting in superior mitigation of skin lesions and modulation of local and systemic metabolic and immunological disorders compared to the MSC-EVs and clinically used anti-IL17A both in vitro and in vivo. Together, the results highlight a novel perspective for psoriasis therapy by nor@MSC-EVs with broad clinical translational potential.

Liver fibrosis is still a serious health concern worldwide, and there is increasing interest in mesenchymal stem cells (MSCs) with tremendous potential for treating this disease because of their regenerative and paracrine effects. Recently, many researches have focused on using the released exosomes (EXOs) from stem cells to treat liver fibrosis rather than using parent stem cells themselves. MSC-derived EXOs (MSC-EXOs) have demonstrated favourable outcomes similar to cell treatment in terms of regenerative, immunomodulatory, anti-apoptotic, anti-oxidant, anti-necroptotic, anti-inflammatory and anti-fibrotic actions in several models of liver fibrosis. EXOs are superior to their parent cells in several terms, including lower immunogenicity and risk of tumour formation. However, maintaining the stability and efficacy of EXOs after in vivo transplantation remains a major challenge in their clinical applicability. Therefore, several strategies have been applied in EXOs engineering, such as parental cell modification or modifying EXOs directly to achieve optimum performance of EXOs in treating liver fibrosis. Herein, we discuss the underlying mechanisms of liver fibrosis with an overview of the available therapies, among them EXOs. We also summarise the recent developments in improving the effectiveness of EXOs with the advantages and limitations of these approaches in terms of the upcoming clinical applications.

Disruption of developmental processes affecting the fetal lung leads to pulmonary hypoplasia. Pulmonary hypoplasia results from several conditions including congenital diaphragmatic hernia (CDH) and oligohydramnios. Both entities have high morbidity and mortality, and no effective therapy that fully restores normal lung development. Hypoplastic lungs have impaired growth (arrested branching morphogenesis), maturation (decreased epithelial/mesenchymal differentiation), and vascularization (endothelial dysfunction and vascular remodeling leading to postnatal pulmonary hypertension). Herein, we discuss the pathogenesis of pulmonary hypoplasia and the role of microRNAs (miRNAs) during normal and pathological lung development. Since multiple cells and pathways are altered, the ideal strategy for hypoplastic lungs is to deliver a therapy that addresses all aspects of abnormal lung development. In this review, we report on a novel regenerative approach based on the administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs). Specifically, we describe the effects of AFSC-EVs in rodent and human models of pulmonary hypoplasia, their mechanism of action via release of their cargo, including miRNAs, and their anti-inflammatory properties. We also compare cargo contents and regenerative effects of EVs from AFSCs and mesenchymal stromal cells (MSCs). Overall, there is compelling evidence that antenatal administration of AFSC-EVs rescues multiple features of fetal lung development in experimental models of pulmonary hypoplasia. Lastly, we discuss the steps that need to be taken to translate this promising EV-based therapy from the bench to the bedside. These include strategies to overcome barriers commonly associated with EV therapeutics and specific challenges related to stem cell-based therapies in fetal medicine.

Oligohydramnios (decreased amniotic fluid volume for gestational age) is a severe condition associated with high morbidity and mortality mainly due to fetal pulmonary hypoplasia. Currently, there are limited treatment options to promote fetal lung development. Administration of stem cells and their derivates have shown promising regenerative properties for several fetal and neonatal diseases related to arrested lung development. Herein, we first characterized pulmonary hypoplasia secondary to oligohydramnios in a surgical rat model. Experimental induction of oligohydramnios led to impaired lung growth, branching morphogenesis (fewer airspaces with decreased Fgf10, Nrp1, Ctnnb1 expression), proximal/distal progenitor cell patterning (decreased Sox2 and Sox9 expression), and TGF-β signaling. We then tested antenatal administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs). In oligohydramnios lungs, AFSC-EV administration improved lung branching morphogenesis and airway progenitor cell patterning at least in part through the release of miR-93-5p. Our experiments suggest that AFSC-EV miR-93-5p blocked SMAD 7, resulting in upregulation of pSMAD2/3 and restoration of TGF-β signaling. Conversely, oligohydramnios lungs treated with antagomir 93-5p transfected AFSC-EVs had decreased branching morphogenesis and TGF-β signaling. This is the first study reporting that antenatal administration of stem cell derivatives could be a potential therapy to rescue lung development in fetuses with oligohydramnios.

Crohn's disease (CD) is a chronic, complex inflammatory disorder of the gastrointestinal tract that presents significant therapeutic challenges. Despite the availability of a wide range of treatments, many patients experience primary non-response, secondary loss of response, or adverse events, limiting the overall effectiveness of current therapies. Clinical trials often report response rates below 60%, partly due to stringent inclusion criteria. Emerging therapies that target novel pathways offer promise in overcoming these limitations. This review explores the latest investigational drugs in phases I, II, and III clinical trials for treating both luminal and perianal CD. We highlight promising therapies that target known mechanisms, including selective Janus kinase inhibitors, anti-adhesion molecules, tumor necrosis factor inhibitors, and IL-23 selective inhibitors. In addition, we delve into novel therapeutic strategies such as sphingosine-1-phosphate receptor modulators, miR-124 upregulators, anti-fractalkine (CX3CL1), anti-TL1A, peroxisome proliferator-activated receptor gamma agonists, TGFBRI/ALK5 inhibitors, anti-CCR9 agents, and other innovative small molecules, as well as combination therapies. These emerging approaches, by addressing new pathways and mechanisms of action, have the potential to surpass the limitations of existing treatments and significantly improve CD management. However, the path to developing new therapies for inflammatory bowel disease (IBD) is fraught with challenges, including complex trial designs, ethical concerns regarding placebo use, recruitment difficulties, and escalating costs. The landscape of IBD clinical trials is shifting toward greater inclusivity, improved patient diversity, and innovative trial designs, such as adaptive and Bayesian approaches, to address these challenges. By overcoming these obstacles, the drug development pipeline can advance more effective, accessible, and timely treatments for CD.

Exposure to ionizing radiation can induce harmful biological effects on the human body, particularly in cases of high-dose γ-irradiation affecting the gastrointestinal tract, bone marrow, skin and lung. Such exposures lead to lethal outcomes as individuals experience a breakdown in their immune system's ability to defend against pathogens, predisposing them to sepsis-induced multiple organ failures. Mesenchymal stromal/stem cells (MSCs) possess diverse biological characteristics, including immunomodulation, anti-inflammation and tissue regeneration. Off-the-shelf culture-expanded human bone marrow- or adipose tissue-derived MSCs are clinically available to treat graft-versus-host disease following hematopoietic cell transplantation and perianal fistulas in Crohn's disease in Japan. While preclinical studies showcase encouraging outcomes in radiation-induced injuries, the effectiveness of MSC transplantation in addressing acute radiation syndrome affecting organs in irradiated individuals is limited. Recent studies have highlighted MSC-releasing extracellular vesicles as nanoparticle substances responsible for outlining the mechanism of action and have identified various components, including proteins and microRNA, that serve as functional molecules. MSC-releasing extracellular vesicle-based therapy emerges as a promising avenue, offering a potential solution to the challenges posed by radiation-induced injuries. However, further investigation is required, especially regarding whether MSC-releasing extracellular vesicles have regenerative effects on tissue-resident stem cells. These unresolved issues represent key aspects that need to be addressed to optimize the therapeutic potential of cell-based and extracellular vesicle-based MSC therapies for interventions in the context of radiation-induced injuries.

Extracellular vesicles (EVs) are nanovesicles released from different cell types from biofluids such as blood, urine, and cerebrospinal fluid. They vary in size and biomarkers, and their biogenesis pathways allow them to be divided into three major types: exosomes, micro-vesicles, and apoptotic bodies. EVs have been studied in the context of diagnosis and therapeutic intervention of various pathological conditions such as cancer, neurodegenerative diseases, and pulmonary diseases. However, the production of EV-based therapeutics can be affected by the source, heterogeneity, or disease, raising questions about the manufacturing and validation of EVs of clinical grade and their scope regarding good manufacturing practice (GMP) in the industry. To address this, we have discussed the state-of-the-art requirements for EV production that must occur in a GMP-compliant environment with a reliable and traceable source. Additionally, EVs' homogeneity and the therapeutics' purity and stability must be analyzed and validated. Quality control measures must also be established to ensure the safety and efficacy of EVs. In conclusion, these considerations must be weighed carefully when manufacturing and validating EVs of clinical grade to ensure their safety and efficacy for therapeutic use.

The global epidemic of metabolic diseases has led to the emergence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH), which pose a significant threat to human health. Despite recent advances in research on the pathogenesis and treatment of MASLD/MASH, there is still a lack of more effective and targeted therapies. Extracellular vesicles (EVs) discovered in a wide range of tissues and body fluids encapsulate different activated biomolecules and mediate intercellular communication. Recent studies have shown that EVs derived from the liver and adipose tissue (AT) play vital roles in MASLD/MASH pathogenesis and therapeutics, depending on their sources and intervention types. Besides, adipose-derived stem cell (ADSC)-derived EVs appear to be more effective in mitigating MASLD/MASH. This review presents an overview of the definition, extraction strategies, and characterisation of EVs, with a particular focus on the biogenesis and release of exosomes. It also reviews the effects and potential molecular mechanisms of liver- and AT-derived EVs on MASLD/MASH, and emphasises the contribution and clinical therapeutic potential of ADSC-derived EVs. Furthermore, the future perspective of EV therapy in a clinical setting is discussed.

Acute myeloid leukemia (AML) stands out as a malignancy of the stem cell precursors of the myeloid lineage. Bone-marrow mesenchymal stem cell-derived exosomes (BMSC-exos) affect AML progression. We explored the effects and mechanism of BMSC-exos on AML cell proliferation and apoptosis.

Human AML cells (MOLM-16, MV-4-11) and normal human hematopoietic cells (GM12878) cultured in vitro were treated with exos extracted from BMSCs that transfected with microRNA (miR)-139-5p-mimics, ovβ-catenin, or miR-139-5p-inhibitor. BMSC morphology was observed by a microscopy, and its adipogenic and osteogenic differentiation abilities were assessed by oil red O staining and alizarin red S staining. BMSC-exos were extracted by ultracentrifugation, and their morphology was observed by a transmission electron microscopy. BMSC-exos were identified by nanoparticle tracking analysis and Western blot. The binding sites between miR-139-5p and β-catenin were predicted by TargetScan database, and then validated by dual-luciferase reporter assay. mRNA levels of miR-139-5p and β-catenin, cell proliferation, and apoptosis were evaluated by RT-qPCR, CCK-8, and flow cytometry. The expressions of CD63, CD81, TSG101, and GRP94 and the proteins of β-catenin, Bax, and Bcl-2 were determined by Western blot.

miR-139-5p was poorly expressed in AML cell lines. miR-139-5p overexpression reduced AML cell viability/proliferation/Bcl-2 level, and raised apoptosis/Bax level. BMSC-exos repressed AML cell proliferation and promoted apoptosis via miR-139-5p. miR-139-5p targeted to inhibit β-catenin expression. Subsequently, up-regulated β-catenin partially counteracted the effects of miR-139-5p in BMSC-exos on AML cell proliferation and apoptosis.

BMSC-exos targeted to repress β-catenin expression by miR-139-5p, limited AML cell proliferation and facilitated apoptosis.

Small extracellular vesicles (SEVs) secreted by mesenchymal stromal cells (MSCs) are considered one of the most promising biological therapies in recent years. The protective effect of MSCs-derived SEVs on myocardium is mainly related to their ability to deliver cargo, anti-inflammatory properties, promotion of angiogenesis, immunoregulation, and other factors. Herein, this review focuses on the biological properties, isolation methods, and functions of SEVs. Then, the roles and potential mechanisms of SEVs and engineered SEVs in myocardial protection are summarized. Finally, the current situation of clinical research on SEVs, the difficulties encountered, and the future fore-ground of SEVs are discussed. In conclusion, although there are some technical difficulties and conceptual contradictions in the research of SEVs, the unique biological functions of SEVs provide a new direction for the development of regenerative medicine. Further exploration is warranted to establish a solid experimental and theoretical basis for future clinical application of SEVs.

Chronic obstructive pulmonary disease (COPD) is characterized by lung remodeling induced by chronic inflammation, presenting challenges for effective treatment. Mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) have shown promise in mitigating inflammation and tissue repairing in various diseases, including COPD. However, the optimal therapeutic pathways for different stages of COPD remain unclear. Transfer RNA-derived small RNAs (tsRNAs) are emerging as key regulators of cellular processes. However, their role in COPD and MSC therapy remains poorly understood.

This study explored the optimal administration routes and efficacy of bone marrow mesenchymal stem cells (BMSCs) and their extracellular vesicles (BMSC-EVs) in treating inflammatory or emphysematous COPD stages in mouse models. Male C57BL/6 mice were exposed to cigarette smoke daily for 6 or 16 weeks, with intraperitoneal CSE injections every 10 days, to model different stages of COPD. Mice were then treated with tracheal or intravenous injections of BMSCs or BMSC-EVs. PKH26 fluorescent dye labeled BMSCs and BMSC-EVs for pulmonary distribution observation. Lung tissue inflammation, apoptosis, EMT, and collagen deposition were assessed using HE staining, TUNEL assay, immunohistochemistry, and Sirius Red staining. Gene and tsRNA expression in lung tissues were analyzed by high-throughput sequencing. Differentially expressed tsRNAs (DE-tsRNAs) were validated by RT-qPCR. Statistical analysis was performed using GraphPad Prism 9.0. Data are presented as mean ± standard deviation (SD).

In 16-week COPD mice characterized by emphysema, tracheal administration of BMSC-EVs showed more significant lung distribution and inhibition of emphysematous pathology. In 6-week COPD mice characterized by inflammation, intravenous injection of BMSCs led to significant pulmonary homing, significantly reduced lung inflammation, apoptosis, EMT, and collagen deposition (P < 0.05). High-throughput sequencing indicated BMSC treatment downregulated genes related to these processes while upregulating mitochondrial function genes. Co-expression networks of DE-tsRNAs and target genes suggested potential roles in COPD. RT-qPCR confirmed significant differential expression of two DE-tsRNAs during COPD progression and BMSC treatment (P < 0.05).

Our study provides insights into selecting MSC and MSC-EV administration routes for different COPD stages. High-throughput sequencing supports BMSCs' inhibitory effects on lung remodeling and identifies the first tsRNA expression profile in a COPD model, warranting further investigation.

Silicosis is one of the most prevalent and fatal occupational diseases worldwide, with unsatisfactory clinical outcomes. This study aimed to investigate the therapeutic effect and related molecular mechanisms of how mesenchymal stem cell (MSC)-secreted exosomes alleviate SiO2-induced pulmonary fibrosis. miR-99a-5p was significantly downregulated in silicosis models via high-throughput miRNA screening, and was overlapped with miRNAs in exosomes from MSCs. miR-99a-5p was significantly downregulated in the lung of a mice silicosis model and in TGFβ1-induced NIH-3T3 cells. In contrast, fibroblast growth factor receptor 3 (FGFR3), a direct target gene of miR-99a-5p, was upregulated in vitro and in vivo. Furthermore, we demonstrated that MSC-derived exosomes deliver enriched miR-99a-5p to target cells and inhibit TGF-β1-induced fibroblast transdifferentiation to reduce collagen protein production. Similarly, in a silicosis mouse model, MSC-derived exosome treatment through the tail veins of the mice counteracted the upregulation of fibrosis-related proteins and collagen deposition in the lung of the mice. By constructing exosomal therapeutic cell models with different miR-99a expressions, we further demonstrated that miR-99a-5p might attenuate pulmonary fibrosis by regulating target protein FGFR3 and downstream mitogen-activated protein kinase (MAPK) signalling pathways. Our study demonstrated that MSC-derived exosomes ameliorate SiO2-induced pulmonary fibrosis by inhibiting fibroblast transdifferentiation and represent an attractive method of pulmonary fibrosis treatment.

Emerging infectious diseases like coronavirus pneumonia (COVID-19) present significant challenges to global health, extensively affecting both human society and the economy. Extracellular vesicles (EVs) have demonstrated remarkable potential as crucial biomedical tools for COVID-19 diagnosis and treatment. However, due to limitations in the performance and titer of natural vesicles, their clinical use remains limited. Nonetheless, EV-inspired strategies are gaining increasing attention. Notably, biomimetic vesicles, inspired by EVs, possess specific receptors that can act as "Trojan horses," preventing the virus from infecting host cells. Genetic engineering can enhance these vesicles by enabling them to carry more receptors, significantly increasing their specificity for absorbing the novel coronavirus. Additionally, biomimetic vesicles inherit numerous cytokine receptors from parent cells, allowing them to effectively mitigate the "cytokine storm" by adsorbing pro-inflammatory cytokines. Overall, this EV-inspired strategy offers new avenues for the treatment of emerging infectious diseases. Herein, this review systematically summarizes the current applications of EV-inspired strategies in the diagnosis and treatment of COVID-19. The current status and challenges associated with the clinical implementation of EV-inspired strategies are also discussed. The goal of this review is to provide new insights into the design of EV-inspired strategies and expand their application in combating emerging infectious diseases.

Exosomes, nano-sized extracellular vesicles, have emerged as a promising tool for the diagnosis and treatment of various intractable diseases, including chronic wounds and cancers. As our understanding of exosomes continues to grow, their potential as a powerful therapeutic modality in medicine is also expanding. This systematic review aims to examine the progress of exosome-based clinical trials and provide a comprehensive overview of the therapeutic perspectives of exosomes.

This systematic review strictly follows PRISMA guidelines and has been registered in PROSPERO, the International Prospective Register of Systematic Reviews. It encompasses articles from January 2000 to January 2023, sourced from bibliographic databases, with targeted search terms targeting exosome applications in clinical trials. During the screening process, strict inclusion and exclusion criteria were applied, including a focus on clinical trials utilizing different cell-derived exosomes for therapeutic purposes.

Among the 522 publications initially identified, only 10 studies met the stringent eligibility criteria after meticulous screening. The selection process involved systematically excluding duplicates and irrelevant articles to provide a transparent overview.

According to our systematic review, exosomes have promising applications in a variety of medical fields, including cell-free therapies and drug delivery systems for treating a variety of diseases, especially cancers and chronic wounds. To ensure safety, potency, and broader clinical applications, further optimization of exosome extraction, loading, targeting, and administration is necessary. While cell-based therapeutics are increasingly utilizing exosomes, this field is still in its infancy, and ongoing clinical trials will provide valuable insights into the clinical utility of exosomes.

Our investigation aims to appraise the neuroprotective impact of Bone Marrow-Mesenchymal Stem Cells (BM-MSCs) derived exosomes against Ag NPs-inducing neurotoxicity in rats.

Twenty-four albino rats were divided into 3 groups. Group I (control negative), Group II (intraperitoneally injected with Ag NPs for 28 days, whereas Group III (intraperitoneally injected with Ag NP and BM-MSCs derived exosomes.

There was a marked elevation of Malondialdehyde (MDA) along with a reduction of brain antioxidants, Gamma-aminobutyric acid (GABA) and Monoamine Oxidase (MAO) in the Ag NPs receiving group. Ag NPs upregulated c-Jun N-terminal Kinases (JNK) genes and c-Myc and downregulated the tissue inhibitors of metalloproteinases (TIMP-1) and Histone deacetylase 1 (HDAC1) genes. Otherwise, the co-treatment of BM-MSCs derived exosomes with Ag NPs could markedly increase the rat's body weight, activity and learning while, decreasing anxiety, restoring all the toxicological parameters and improving the microscopic appearance of different brain areas.

BM-MSCs-derived exosomes downregulated both apoptotic and inflammatory mediators and upregulated the antiapoptotic genes. BM-MSCs-derived exosomes exhibit a great therapeutic effect against the neurotoxic effects of Ag NPs.

Exosomes are nanosized, lipid membrane vesicles secreted by cells, facilitating intercellular communication by transferring cargo from parent to recipient cells. This capability enables biological crosstalk across multiple tissues and cells. Extensive research has been conducted on their role in the pathogenesis of degenerative musculoskeletal diseases such as osteoarthritis (OA), a chronic and painful joint disease that particularly affects cartilage. Currently, no effective treatment exists for OA. Given that exosomes naturally modulate synovial joint inflammation and facilitate cartilage matrix synthesis, they are promising candidates as next generation nanocarriers for OA therapy. Recent advancements have focused on engineering exosomes through endogenous and exogenous approaches to enhance their joint retention, cartilage and chondrocyte targeting properties, and therapeutic content enrichment, further increasing their potential for OA drug delivery. Notably, charge-reversed exosomes that utilize electrostatic binding interactions with cartilage anionic aggrecan glycosaminoglycans have demonstrated the ability to penetrate the full thickness of early-stage arthritic cartilage tissue following intra-articular administration, maximizing their therapeutic potential. These exosomes offer a non-viral, naturally derived, cell-free carrier for OA drug and gene delivery applications. Efforts to standardize exosome harvest, engineering, and property characterization methods, along with scaling up production, will facilitate more efficient and rapid clinical translation. This article reviews the current state-of-the-art, explores opportunities for exosomes as OA therapeutics, and identifies potential challenges in their clinical translation.

Modern methods of molecular diagnostics and therapy have revolutionized the field of medicine in recent years by providing more precise and effective tools for detecting and treating diseases. This progress includes a growing exploration of the body's secreted vesicles, known as extracellular vesicles (EVs), for both diagnostic and therapeutic purposes. EVs are a heterogeneous population of lipid bilayer vesicles secreted by almost every cell type studied so far. They are detected in body fluids and conditioned culture media from living cells. EVs play a crucial role in communication between cells and organs, both locally and over long distances. They are recognized for their ability to transport endogenous RNA and proteins between cells, including messenger RNA (mRNA), microRNA (miRNA), misfolded neurodegenerative proteins, and several other biomolecules. This review explores the dual utilization of EVs, serving not only for diagnostic purposes but also as a platform for delivering therapeutic molecules to cells and tissues. Through an exploration of their composition, biogenesis, and selective cargo packaging, we elucidate the intricate mechanisms behind RNA transport between cells via EVs, highlighting their potential use for both diagnostic and therapeutic applications. Finally, it addresses challenges and outlines prospective directions for the clinical utilization of EVs.

Extracellular vesicles (EVs)-based intercellular communication (through exosomes, microvesicles, and apoptotic bodies) is conserved across all kingdoms of life. In recent years, exosomes have gained much attention for targeted pharmaceutical administration due to their unique features, nanoscale size, and capacity to significantly contribute to cellular communication. As drug delivery vehicles, exosomes have several advantages over alternative nanoparticulate drug delivery technologies. A key advantage lies in their comparable makeup to the body's cells, which makes them non-immunogenic. However, exosomes vesicles face several challenges, including a lack of an effective and standard production technique, decreased drug loading capacity, limited characterization techniques, and underdeveloped isolation and purification procedures. Exosomes are well known for their long-term safety and natural ability to transport intercellular nucleic acids and medicinal compounds across the blood-brain-barrier (BBB). Therefore, in addition to revealing new insights into exosomes' distinctiveness, the growing availability of new analytical tools may drive the development of next-generation synthetic systems. Herein, light is shed on exosomes as drug delivery vehicles in anti-infective therapy by reviewing the literature on primary articles published between 2002 and 2023. Additionally, the benefits and limitations of employing exosomes as vehicles for therapeutic drug delivery are also discussed.

Mesenchymal stem cells (MSC) therapy for acute respiratory distress syndrome (ARDS) represents a burgeoning treatment approach, supported by numerous preclinical studies confirming its efficacy. Our study aims to provide a comprehensive evaluation of both the safety and effectiveness of MSC.

We conducted searches across three databases (PubMed, Embase, Cochrane) for randomized controlled studies up to June 23, 2024. A meta-analysis was performed on variables including adverse events, mortality, changes in the PaO2/FiO2 ratio, intensive care unit (ICU), length of stay, ventilation-free days, and changes in pro-inflammatory and anti-inflammatory cytokines. Relative risk (RR) values were employed for dichotomous variables, while mean difference (MD) and standard mean difference (SMD) were used for continuous variables. Risk bias was assessed using risk of bias 2 (ROB2).

The meta-analysis encompassed 17 experiments involving 796 patients, with 410 undergoing MSC treatment and 386 in the control group. Primary outcomes indicated that MSC treatment did not escalate adverse events [RR =1.04; 95% confidence interval (CI): 0.90, 1.19; P=0.59; I2=0%]. On the contrary, it significantly diminishes the mortality (RR =0.79; 95% CI: 0.64, 0.97; P=0.02; I2=0%). Regarding secondary outcomes, MSCs led to a significant improvement in the PaO2/FiO2 ratio for ARDS patients (SMD =0.53; 95% CI: 0.15, 0.92; P=0.007; I2=0%). However, there were no significant differences in ICU length of stay (MD =-1.77; 95% CI: -6.97, 3.43; P=0.50; I2=63%) and ventilation-free days (MD =-1.29; 95% CI: -4.09, 1.51; P=0.37; I2=0%). MSCs significantly lowered C-reactive protein (CRP) (SMD =-0.65; 95% CI: -1.18, -0.13; P=0.01; I2=56%) and interleukin-6 (IL-6) levels compared to the control group (SMD =-0.76; 95% CI: -1.34, -0.17; P=0.01; I2=74%). However, changes in interleukin-10 (AIL-10) (SMD =-0.46; 95% CI: -1.51, 0.58; P=0.38; I2=77%), and changes in tumor necrosis factor-alpha (ATNF-α) (SMD =-1.5; 95% CI: -3.39, 0.40; P=0.12; I2=92%) levels showed no significant changes.

MSC therapy demonstrates reliable safety, with a significant impact on reducing mortality and improving certain clinical symptoms. Moreover, in certain aspects, it may alleviate the inflammatory response in ARDS. Nonetheless, these findings necessitate validation through additional high-quality randomized controlled trials.

Although treatment for multiple sclerosis (MS) has undergone a revolution in the last decades, at least two important barriers remain: alleviation of innate inflammation driving disease progression and promotion of remyelination and neural regeneration. Mesenchymal stem cells (MSCs) possess immunomodulatory properties and promote remyelination in murine MS models. The main therapeutic mechanism has, however, been attributed to their potent paracrine capacity, and not to in vivo tissue implantation. Studies have demonstrated that exosomes released as part of the cells' secretome effectively encapsulate the beneficial properties of MSCs. These membrane-enclosed nanoparticles contain a variety of proteins and nucleic acids and serve as mediators of intercellular communication. In vitro studies have demonstrated that exosomes from MSCs modulate activated microglia from an inflammatory to an anti-inflammatory phenotype and thereby dampen the innate inflammation. Rodent studies have also demonstrated potent immunomodulation and remyelination with improved outcomes following exosome administration. Thus, exosomes from MSCs may represent a potential cell-free treatment modality to prevent disease progression and promote remyelination in MS. In this narrative review, we summarize the current knowledge of exosomes from MSCs as a potential treatment for MS and discuss the remaining issues before successful translation into clinical trials.

Cell membranes are crucial elements in living organisms, serving as protective barriers and providing structural support for cells. They regulate numerous exchange and communication processes between cells and their environment, including interactions with other cells, tissues, ions, xenobiotics, and drugs. However, the complexity and heterogeneity of cell membranes-comprising two asymmetric layers with varying compositions across different cell types and states (e.g., healthy vs. diseased)-along with the challenges of manipulating real cell membranes represent significant obstacles for in vivo studies. To address these challenges, researchers have developed various methodologies to create model cell membranes or membrane fragments, including mono- or bilayers organized in planar systems. These models facilitate fundamental studies on membrane component interactions as well as the interactions of membrane components with external agents, such as drugs, nanoparticles (NPs), or biomarkers. The applications of model cell membranes have extended beyond basic research, encompassing areas such as biosensing and nanoparticle camouflage to evade immune detection. In this review, we highlight advancements in the engineering of planar model cell membranes, focusing on the nanoarchitectonic tools used for their fabrication. We also discuss approaches for incorporating challenging materials, such as proteins and enzymes, into these models. Finally, we present our view on future perspectives in the field of planar model cell membranes.

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have shown anti-inflammatory potential in multiple inflammatory diseases. In the March 2022 issue of the Journal of Extracellular Vesicles, it was shown that EVs from human MSCs can suppress severe acute respiratory distress syndrome, coronavirus 2 (SARS-CoV-2) replication and can mitigate the production and release of infectious virions. We therefore hypothesized that MSC-EVs have an anti-viral effect in SARS-CoV-2 infection in vivo. We extended this question to ask whether also other respiratory viral infections could be treated by MSC-EVs. Adipose stem cell-derived EVs (ASC-EVs) were isolated using tangential flow filtration from conditioned media obtained from a multi-flask cell culture system. The effects of the ASC-EVs were tested  in Vero E6 cells in vitro. ASC-EVs were also given i.v. to SARS-CoV-2 infected Syrian Hamsters, and H1N1 influenza virus infected mice. The ASC-EVs attenuated SARS-CoV-2 virus replication in Vero E6 cells and reduced body weight and signs of lung injury in infected Syrian hamsters. Furthermore, ASC-EVs increased the survival rate of influenza A-infected mice and attenuated signs of lung injury. In summary, this study suggests that ASC-EVs can have beneficial therapeutic effects in models of virus-infection-associated acute lung injury and may potentially be developed to treat lung injury in humans.

Joint diseases greatly impact the daily lives and occupational functioning of patients globally. However, conventional treatments for joint diseases have several limitations, such as unsatisfatory efficacy and side effects, necessitating the exploration of more efficacious therapeutic strategies. Mesenchymal stem cell (MSC)-derived EVs (MSC-EVs) have demonstrated high therapeutic efficacyin tissue repair and regeneration, with low immunogenicity and tumorigenicity. Recent studies have reported that EVs-based therapy has considerable therapeutic effects against joint diseases, including osteoarthritis, tendon and ligament injuries, femoral head osteonecrosis, and rheumatoid arthritis. Herein, we review the therapeutic potential of various types of MSC-EVs in the aforementioned joint diseases, summarise the mechanisms underlying specific biological effects of MSC-EVs, and discuss future prospects for basic research on MSC-EV-based therapeutic modalities and their clinical translation. In general, this review provides an in-depth understanding of the therapeutic effects of MSC-EVs in joint diseases, as well as the underlying mechanisms, which may be beneficial to the clinical translation of MSC-EV-based treatment. The translational potential of this article: MSC-EV-based cell-free therapy can effectively promote regeneration and tissue repair. When used to treat joint diseases, MSC-EVs have demonstrated desirable therapeutic effects in preclinical research. This review may supplement further research on MSC-EV-based treatment of joint diseases and its clinical translation.

Mesenchymal stromal cells (MSCs) exert immunomodulatory effects, primarily through released extracellular vesicles (EVs). For the clinical-grade manufacturing of MSC-EV products culture conditions need to support MSC expansion and allow the manufacturing of potent MSC-EV products. Traditionally, MSCs are expanded in fetal bovine serum-supplemented media. However, according to good manufacturing practice (GMP) guidelines the use of animal sera should be avoided. To this end, human platelet lysate (hPL) has been qualified as an animal serum replacement. Although hPL outcompetes animal sera in promoting MSC expansion, hPL typically contains components of the coagulation system that need to be inhibited or removed to avoid coagulation reactions in the cell culture. Commonly, heparin is utilized as an anticoagulant; however, higher concentrations of heparin can negatively impact MSC viability, and conventional concentrations alone do not sufficiently prevent clot formation in prepared media.

To circumvent unwanted coagulation processes, this study compared various clotting prevention strategies, including different anticoagulants and calcium chloride (CaCl2)-mediated declotting methods, which in combination with heparin addition was found effective. We evaluated the influence of the differently treated hPLs on the proliferation and phenotype of primary bone marrow-derived MSCs and identified the CaCl2-mediated declotting method as the most effective option. To determine whether CaCl2 declotted hPL allows the manufacturing of immunomodulatory MSC-EV products, EVs were prepared from conditioned media of MSCs expanded with either conventional or CaCl2 declotted hPL. In addition to metric analyses, the immunomodulatory potential of resulting MSC-EV products was assessed in a recently established multi-donor mixed lymphocyte reaction assay.

Our findings conclusively show that CaCl2-declotted hPLs support the production of immunomodulatory-active MSC-EV products.

Mesenchymal stem cells (MSCs) are multipotent stem cells that are able to differentiate into multiple lineages including bone, cartilage, muscle and fat. They hold immunomodulatory properties and therapeutic ability to treat multiple diseases, including autoimmune and chronic degenerative diseases. In this article, we reviewed the different biological properties, applications and clinical trials of MSCs. Also, we discussed the basics of manufacturing conditions, quality control, and challenges facing MSCs in the clinical setting.

Extensive review of the literature was conducted through the databases PubMed, Google Scholar, and Cochrane. Papers published since 2015 and covering the clinical applications and research of MSC therapy were considered. Furthermore, older papers were considered when referring to pioneering studies in the field.

The most widely studied stem cells in cell therapy and tissue repair are bone marrow-derived mesenchymal stem cells. Adipose tissue-derived stem cells became more common and to a lesser extent other stem cell sources e.g., foreskin derived MSCs. MSCs therapy were also studied in the setting of COVID-19 infections, ischemic strokes, autoimmune diseases, tumor development and graft rejection. Multiple obstacles, still face the standardization and optimization of MSC therapy such as the survival and the immunophenotype and the efficiency of transplanted cells. MSCs used in clinical settings displayed heterogeneity in their function despite their extraction from healthy donors and expression of similar surface markers.

Mesenchymal stem cells offer a rising therapeutic promise in various diseases. However, their potential use in clinical applications requires further investigation.

Infection with SARS-CoV-2, the virus responsible for COVID-19 diseases, can impact different tissues and induce significant cellular alterations. The production of extracellular vesicles (EVs), which are physiologically involved in cell communication, is also altered during COVID-19, along with the dysfunction of cytoplasmic organelles. Since circulating EVs reflect the state of their cells of origin, they represent valuable tools for monitoring pathological conditions. Despite challenges in detecting EVs due to their size and specific cellular compartment origin using different methodologies, flow cytometry has proven to be an effective method for assessing the role of EVs in COVID-19. This review summarizes the involvement of plasmatic EVs in COVID-19 patients and individuals with Long COVID (LC) affected by post-acute sequelae of SARS-CoV-2 infection (PASC), highlighting their dual role in exerting both pro- and antiviral effects. We also emphasize how flow cytometry, with its multiparametric approach, can be employed to characterize circulating EVs, particularly in infectious diseases such as COVID-19, and suggest their potential role in chronic impairments during post-infection.