The development of mesenchymal stem cell therapy in the present, and the perspective of cell-free therapy in the future

Biomimetic nanostructural materials based on placental amniotic membrane-derived nanofibers for self-healing and anti-adhesion during cesarean section

Cesarean section (CS) is highly prevalent surgery among females. However, current absorbable anti-adhesion membranes used clinically can partially prevent postoperative adhesions but show limited efficacy in tissue regeneration, leaving post-cesarean women at risk for severe complications including cesarean scar pregnancy, placenta previa, and uterine rupture. Herein, we designed a fully amniotic membrane (AM)-derived biomimetic nanostructural materials (AM-BNMs) as an anti-adhesion barrier, and validated its therapeutic efficacy in a rat CS model. The biomaterial consisted of AM-extracellular matrix (ECM) nanofibers, enriched with hemostatic proteins (collagen, S100A8, S100A9, etc.), carrying AM mesenchymal stem cells (MSCs)-secretome that exhibited significantly elevated levels of pro-regenerative factors (miR-302a-3p, angiogenin, VEGF, etc.) compared to endogenous secretion. The reconstituted AM-BNMs demonstrated synergistic effects at CS wounds, effectively preventing adhesion formation while promoting hemostasis and tissue regeneration. In summary, this readily accessible human-derived biomaterial shows promising potential in preventing adhesion-related complications and enhancing uterine wound healing, thereby promoting female reproductive health.

Hydrogel-integrated exosome mimetics derived from osteogenically induced mesenchymal stem cells in spheroid culture enhance bone regeneration

Exosomes derived from mesenchymal stem cells (MSCs) offer a promising alternative to traditional cell-based therapies for tissue repair by mitigating risks associated with the transplantation of living cells. However, insufficient osteogenic capacity of exosomes diminishes their potential in bone tissue regeneration. Here, we report novel osteogenically induced exosome mimetics (EMs) integrated into injectable hydrogel carriers for improved bone regeneration. EMs were produced by a serial extrusion of MSCs cultured as spheroids during osteogenic induction. The prepared EMs were chemically anchored on a self-healing hydrogel assembled by guanidinylated hyaluronic acid and silica-rich nanoclays for sustained release of EMs. The administration of hydrogel-integrated EMs into mouse calvarial defects resulted in robust bone tissue regeneration. miRNA sequencing revealed altered expression of specific miRNAs in the EMs related to Wnt/β-catenin and Notch signaling pathways. Our study provides new insights into the development of advanced exosome-based cell-free therapies for bone tissue engineering.

Valproic acid preconditioning of bone marrow mesenchymal stem cells promotes remyelination of the corpus callosum in a cuprizone-induced demyelination model

Multiple sclerosis (MS) is an inflammatory demyelinating disorder that currently has no exact treatment. However, stem cell therapy shows promise in treating neurodegenerative disorders. One of the main challenges with this treatment is the high apoptosis rate and low migration capacity of the transplanted stem cells. In this study we used Valproic acid (VPA) for preconditioning of bone marrow mesenchymal stem cells (BM-MSCs) before transplantation into the cuprizone induced demyelination model in C57/BL6 mice. Cell viability and CXCR4 mRNA expression and protein levels were assessed after preconditioning of BM-MSCs with VPA. Homing of BM-MSCs into the corpus callosum and visceral organs (liver and lung) were assessed 48 h after intravenous transplantation. Also, myelin content and the number of oligodendrocytes and astrocytes were evaluated in the corpus callosum. Our results indicated that 3 h VPA (5 mM) preconditioning of BM-MSCs led to an increase in viability and CXCR4 mRNA and protein levels in BM-MSCs. After IV transplantation VPA preconditioned BM-MSCs had a greater homing ability into the CNS but not to the visceral organs than non-preconditioned BM-MSCs. Also, transplantation of VPA preconditioned BM-MSCs resulted in a significant increase in remyelination and the number of oligodendrocytes while decreasing the number of astrocytes. These findings suggest that VPA preconditioning enhances the therapeutic efficacy of BM-MSCs when applied to cuprizone induced demyelination model.

Cell membrane-derived nanovesicles as extracellular vesicle-mimetics in wound healing

Cell membrane-derived nanovesicles (NVs) have emerged as promising alternatives to extracellular vesicles (EVs) for wound healing applications, addressing the limitations of traditional EVs, which include insufficient targeting capability, low production yield, and limited drug-loading capacity. Through mechanical cell extrusion methods, NVs exhibit superior characteristics, demonstrating enhanced yield, stability, and purity compared to natural EVs. These NVs can be derived from various membrane sources, including single cell types (stem cells, blood cells, immune cells, and bacterial membranes), hybrid cell membranes and cell membranes mixed with liposomes, with each offering unique therapeutic properties. The integration of genetic engineering and surface modifications has further enhanced NV functionality, enabling precise targeting and improved drug delivery capabilities. Recent advances in NV-based therapies have demonstrated their potential across multiple biomedical applications. Although challenges persist in terms of standardization, storage stability, and clinical translation, the combination of natural cell-derived functions with artificial modification potential positions NVs as a promising platform for next-generation therapeutic delivery systems, thereby offering new possibilities in wound healing applications. Finally, we explore the challenges and future prospects of translating NV-based therapeutics into clinical practice, providing insights into the future development of this innovative approach in wound healing and tissue repair.

Clinical translation of mesenchymal stem cells in ischemic heart failure: Challenges and future perspectives

Myocardial infarction (MI) with resulting congestive heart failure is one of the leading causes of death worldwide. Current therapies for treating MI, such as devices, traditional medicine, and surgeries, come with many limitations as patients in their final stages of heart failure have little chances of experiencing any reversible changes. In recent decades, Mesenchymal stem cell (MSC) based therapy has become one of the most popular and rapidly developing fields in treating MI. Their supremacy for clinical applications is partially due to their unique properties and encouraging pre-clinical outcomes in various animal disease models. However, the majority of clinical trials registered for MSC therapy for diverse human diseases, including MI, have fallen short of expectations. This review intends to discuss the recent advances in the clinical application of using MSCs for cardiac repair and discuss challenges facing the clinical translation of MSCs for cardiac regeneration such as restoration of endothelial-cardiomyocyte crosstalk, immunomodulation and immune rejection, poor homing and migration, as well as low retention and survival. Furthermore, we will discuss recent strategies being investigated to help overcome some of these challenges.

Epigenetic mechanisms in stem cell therapies for achilles tendinopathy

Achilles tendinopathy (AT) is a chronic degenerative tendinopathy that affects people's daily lives. Multiple clinical studies have found that current conservative treatments fail to promote quality tendon healing. Recent studies have found that stem cell therapy can target pathophysiological changes in the tendon by replenishing tendon-derived cells, promoting extracellular matrix (ECM) remodeling, and modulating the inflammatory response to improve the microenvironment of Achilles tendon regeneration. And epigenetic modifications play an important role in stem cell fate determination and function. In this review, we provided a brief overview of the biological properties of relevant stem cells. The influence of epigenetic modifications on stem cell proliferation, differentiation, and immune regulatory function in the treatment of AT was also explored. We focused on gene regulatory mechanisms controlled by DNA methylation, histones and non-coding RNAs including microRNAs, circRNAs and long non-coding RNAs. We also discuss the current challenges faced by stem cell therapies in treating AT and their potential solutions. Further research in this area will provide a more comprehensive epigenetic explanation for stem cell therapy for AT, leading to the development of stable, safe and effective stem cell therapies.

Therapeutic Approaches and Potential Mechanisms of Small Extracellular Vesicles in Treating Vascular Dementia

Small extracellular vesicles (sEVs), including exosomes as a subtype, with a diameter typically less than 200 nm and originating from the endosomal system, are capable of transporting a diverse array of bioactive molecules, including proteins, nucleic acids, and lipids, thereby facilitating intercellular communication and modulating cellular functions. Vascular dementia (VaD) represents a form of cognitive impairment attributed to cerebrovascular disease, characterized by a complex and multifaceted pathophysiological mechanism. Currently, the therapeutic approach to VaD predominantly emphasizes symptom management, as no specific pharmacological treatment exists to cure the condition. Recent investigations have illuminated the significant role of sEVs in the pathogenesis of vascular dementia. This review seeks to provide a comprehensive analysis of the characteristics and functions of sEVs, with a particular focus on their involvement in vascular dementia and its underlying mechanisms. The objective is to advance the understanding of the interplays between sEVs and vascular dementia, thereby offering novel insights for future research and therapeutic strategies.

Extracellular vesicles from mesenchymal stem cells improve liver injury in rats with mild liver damage. Underlying mechanisms and role of TGFβ

Preventing the progression of liver damage to fibrosis would be beneficial for patients with steatotic liver disease (SLD). Mesenchymal stem cells (MSC) are a promising therapy for SLD and derived extracellular vesicles (EVs) could even improve the treatment's efficacy and safety. However, the mechanisms of MSC-EVs beneficial effects are not well known. It has been suggested that modifying the EVs cargo could improve their beneficial effects. The aims of this study were to assess if MSC-EVs reduce liver damage in a rat model of mild liver damage; to analyze the underlying mechanisms and to assess if silencing TGFβ enhances the beneficial effects of MSC-EVs. CCl4 was injected three times per week during four weeks to induce mild liver damage. EVs from human adipocyte MSC and from TGFβ-depleted MSC (siTGFβ-MSC-EVs) were injected in the tail vein. Steatosis, fibrosis, liver inflammation, macrophage infiltration and liver content of fibrotic markers, DAMPs, cytokines and bile acids were analyzed. Normal MSC-EVs reduce the CCL2 increase in liver, macrophage infiltration and the increases in the fibrosis markers collagen I and α-SMA. Treatment with siTGFβ-MSC-EVs, in addition, reduces liver steatosis, the increase of bile acids (mainly TCA), and DAMP HMGB1 levels, inducing a larger reduction of collagen I in liver of CCl4 rats. Treatment with MSCs-EVs effectively reduces early liver damage. Silencing of TGFβ in MSCs enhances the beneficial effects by additional mechanisms. Early treatment with MSC-EVs, especially after silencing TGFβ, could improve liver damage in SLD patients.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Mesenchymal stem cells and their extracellular vesicle therapy for neurological disorders: traumatic brain injury and beyond

Traumatic brain injury (TBI) is a complex condition involving mechanisms that lead to brain dysfunction and nerve damage, resulting in significant morbidity and mortality globally. Affecting ~50 million people annually, TBI's impact includes a high death rate, exceeding that of heart disease and cancer. Complications arising from TBI encompass concussion, cerebral hemorrhage, tumors, encephalitis, delayed apoptosis, and necrosis. Current treatment methods, such as pharmacotherapy with dihydropyridines, high-pressure oxygen therapy, behavioral therapy, and non-invasive brain stimulation, have shown limited efficacy. A comprehensive understanding of vascular components is essential for developing new treatments to improve blood vessel-related brain damage. Recently, mesenchymal stem cells (MSCs) have shown promising results in repairing and mitigating brain damage. Studies indicate that MSCs can promote neurogenesis and angiogenesis through various mechanisms, including releasing bioactive molecules and extracellular vesicles (EVs), which help reduce neuroinflammation. In research, the distinctive characteristics of MSCs have positioned them as highly desirable cell sources. Extensive investigations have been conducted on the regulatory properties of MSCs and their manipulation, tagging, and transportation techniques for brain-related applications. This review explores the progress and prospects of MSC therapy in TBI, focusing on mechanisms of action, therapeutic benefits, and the challenges and potential limitations of using MSCs in treating neurological disorders.

Inhibition of Small Extracellular Vesicles by GW4869 Does not Disrupt the Paracrine Regulation of Adipose-Derived Mesenchymal Stem Cells Over Keloid Fibroblasts

BACKGROUND

Keloid, scar caused by atypical wound repair, represents a significant difficulty for specialists in plastic surgery and dermatology. Adipose-derived mesenchymal stem cells (ADSCs) can regulate fibrotic phenotypes of keloid fibroblasts (KFs) in a paracrine fashion, but whether small extracellular vesicles (SEVs) are the key functional carrier in ADSC paracrine regulation of KFs remains unknown. This study aims to explore whether the regulatory effects of conditioned medium (CM) obtained from ADSCs on KFs can be impaired by decreased SEV content in the ADSC-CM.

METHODS

Clinical specimens were utilized to extract keloid fibroblasts (KFs), normal fibroblasts (NFs), and adipose-derived stem cells (ADSCs). Fibroblasts were cultured with CM obtained from ADSCs untreated or treated with the sphingomyelinase inhibitor GW4869. The features of SEVs derived from ADSC-CM were characterized, and fibroblast proliferation, migration, apoptosis, and expression of ECM proteins were analyzed.

RESULTS

The sphingomyelinase inhibitor GW4869 successfully reduced the SEV content in ADSC-CM, and both control ADSC-CM and ADSC-CM with reduced SEV content significantly inhibited KF proliferation, migration, and α-SMA synthesis but not KF apoptosis, whereas only NF proliferation was inhibited by ADSC-CM. The reduced SEV content only affected the inhibition of KF proliferation induced by ADSC-CM.

CONCLUSION

ADSC-CM inhibits various fibrotic phenotypes of KFs, but decreasing the SEV content in ADSC-CM did not significantly alter the antifibrotic effects of ADSC-CM. Thus, SEVs may not be the key mediator of ADSCs paracrine regulation of KFs.

NO LEVEL ASSIGNED

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Regulatory Immune Cell-derived Exosomes: Modes of Action and Therapeutic Potential in Transplantation

Reduced dependence on antirejection agents, improved long-term allograft survival, and induction of operational tolerance remain major unmet needs in organ transplantation due to the limitations of current immunosuppressive therapies. To address this challenge, investigators are exploring the therapeutic potential of adoptively transferred host- or donor-derived regulatory immune cells. Extracellular vesicles of endosomal origin (exosomes) secreted by these cells seem to be important contributors to their immunoregulatory properties. Twenty years ago, it was first reported that donor-derived exosomes could extend the survival of transplanted organs in rodents. Recent studies have revealed that regulatory immune cells, such as regulatory myeloid cells (dendritic cells, macrophages, or myeloid-derived suppressor cells), regulatory T cells, or mesenchymal stem/stromal cells can suppress graft rejection via exosomes that express a cargo of immunosuppressive molecules. These include cell surface molecules that interact with adaptive immune cell receptors, immunoregulatory enzymes, and micro- and long noncoding RNAs that can regulate inflammatory gene expression via posttranscriptional changes and promote tolerance through promotion of regulatory T cells. This overview analyzes the diverse molecules and mechanisms that enable regulatory immune cell-derived exosomes to modulate alloimmunity and promote experimental transplant tolerance. We also discuss the potential benefits and limitations of their application as therapeutic entities in organ transplantation.

Application of mesenchymal stem cells in liver fibrosis and regeneration

Liver transplantation remains the most effective treatment for end-stage liver disease (ESLD), but it is fraught with challenges such as immunosuppression, high risk and cost, and donor shortage. In recent years, stem cell transplantation has emerged as a promising new strategy for ESLD treatment, with mesenchymal stem cells (MSCs) gaining significant attention because of their unique properties. MSCs can regulate signaling pathways, including hepatocyte growth factor/c-Met, Wnt/beta (β)-catenin, Notch, transforming growth factor-β1/Smad, interleukin-6/Janus kinase/signal transducer and activator of transcription 3, and phosphatidylinositol 3-kinase/PDK/Akt, thereby influencing the progression of liver fibrosis and regeneration. As a promising stem cell type, MSCs offer numerous advantages in liver disease treatment, including low immunogenicity; ease of acquisition; unlimited proliferative ability; pluripotent differentiation potential; immunomodulatory function; and anti-inflammatory, antifibrotic, and antiapoptotic biological characteristics. This review outlines the mechanisms by which MSCs reverse liver fibrosis and promote liver regeneration. MSCs are crucial in reversing liver fibrosis and repairing liver damage through the secretion of growth factors, regulation of signaling pathways, and modulation of immune responses. MSCs have shown good therapeutic effects in preclinical and clinical studies, providing new strategies for liver disease treatment. However, challenges still exist in the clinical application of MSCs, including low differentiation efficiency and limited sources. This review provides a reference for MSC application in liver disease treatment. With the continuous progress in MSC research, MSCs are expected to achieve breakthroughs in liver disease treatment, thereby improving patient treatment outcomes.

MSC-microvesicles protect cartilage from degradation in early rheumatoid arthritis via immunoregulation

OBJECTIVE

As research into preclinical rheumatoid arthritis (pre-RA) has advanced, a growing body of evidence suggests that abnormalities in RA-affected joint cartilage precede the onset of arthritis. Thus, early prevention and treatment strategies are imperative. In this study, we aimed to explore the protective effects of mesenchymal stem cell (MSC)-derived microvesicles (MVs) on cartilage degradation in a collagen-induced arthritis (CIA) mouse model.

METHODS

A CIA mouse model was established to observe early pathological changes in cartilage (days 21-25) through histological and radiological examinations. On day 22, MSCs-MVs were intravenously injected into the mice with CIA. Radiological, histological, and flow cytometric examinations were conducted to observe inflammation and cartilage changes in these mice compared to the mice with CIA and the control mice. In vitro, chondrocytes were cultured with inflammatory factors such as IL-1β and TNFα to simulate inflammatory damage to cartilage. After the addition of MVs, changes in inflammatory levels and collagen expression were measured via Western blotting, immunofluorescence, enzyme-linked immunosorbent assays (ELISAs), and quantitative PCR to determine the role of MVs in maintaining chondrocytes.

RESULTS

MSC-MVs expressed vesicular membrane proteins (CD63 and Annexin V) and surface markers characteristic of MSCs (CD44, CD73, CD90, and CD105). In the early stages of CIA in mice, a notable decrease in collagen content was observed in the joint cartilage. In mice with CIA, injection of MSCs-MVs resulted in a significant reduction in the peripheral blood levels of IL-1β, TNFα, and IL-6, along with a decrease in the ratio of proinflammatory T and B cells. Additionally, MSC-MVs downregulated the expression of IL-1β, TNFα, MMP-13, and ADAMTS-5 in cartilage while maintaining the stability of type I and type II collagen. These MVs also attenuated the destruction of cartilage, which was evident on imaging. In vitro experiments demonstrated that MSC-MVs effectively suppressed the secretion of the inflammatory factors IL-1β, TNFα, and IL-6 in stimulated peripheral blood mononuclear cells (PBMCs).

CONCLUSIONS

MSCs-MVs can inhibit the decomposition of the inflammation-induced cartilage matrix by regulating immune cell inflammatory factors to attenuate cartilage destruction. MSC-MVs are promising effective treatments for the early stages of RA.

Efficacy of stem cell therapy in patients with chronic liver disease: an umbrella review of systematic reviews

BACKGROUND

Stem cell therapy offers promising benefits like modulating immune responses, reducing inflammation, and aiding liver regeneration. This umbrella review seeks to compile evidence from systematic reviews to assess the efficacy of stem cell therapy for improving liver function and survival rates in chronic liver disease patients.

METHODS

We searched electronic databases up to February 15, 2024. The selection process focused on systematic reviews comparing stem cell therapy with standard care or a placebo. The primary outcomes evaluated were changes in liver enzymes, the Model for End-Stage Liver Disease score, and survival rates. Nested Knowledge software was utilized for screening and data extraction. All statistical analyses were performed using R software, version 4.3.

RESULTS

Our umbrella review included 28 systematic reviews. The meta-analysis showcased a notable improvement in survival rates with a pooled relative risk of 1.487 [95% confidence interval (CI): 1.281-1.727). In nonrandomized studies, albumin levels exhibited a standardized mean difference (SMD) of 0.786 (95% CI: 0.368-1.204), indicating positive therapeutic effects. For alanine aminotransferase, the meta-analysis revealed a decrease in levels with an SMD of -0.499 (95% CI: -0.834 to -0.164), and for aspartate aminotransferase, an overall SMD of -0.362 (95% CI: -0.659 to -0.066) was observed, suggesting hepatoprotective effects. No significant changes were observed in total bilirubin levels and Model for End-Stage Liver Disease scores in randomized controlled trials.

CONCLUSION

Stem cell therapy exhibits potential as a novel treatment for chronic liver diseases, as it has demonstrated improvements in survival rates and certain liver function markers. More high-quality randomized controlled trials are needed in the future to fully ascertain the efficacy of stem cell therapy in this patient population.

Mitochondrial quality control dysfunction in osteoarthritis: Mechanisms, therapeutic strategies & future prospects

Osteoarthritis (OA) is a prevalent chronic joint disease characterized by articular cartilage degeneration, pain, and disability. Emerging evidence indicates that mitochondrial quality control dysfunction contributes to OA pathogenesis. Mitochondria are essential organelles to generate cellular energy via oxidative phosphorylation and regulate vital processes. Impaired mitochondria can negatively impact cellular metabolism and result in the generation of harmful reactive oxygen species (ROS). Dysfunction in mitochondrial quality control mechanisms has been increasingly linked to OA onset and progression. This review summarizes current knowledge on the role of mitochondrial quality control disruption in OA, highlighting disturbed mitochondrial dynamics, impaired mitochondrial biogenesis, antioxidant defenses and mitophagy. The review also discusses potential therapeutic strategies targeting mitochondrial Quality Control in OA, offering future perspectives on advancing OA therapeutic strategies.

Comparison of the Therapeutic Efficacy and Autophagy-Mediated Mechanisms of Action of Urine-Derived and Adipose-Derived Stem Cells in Osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a prevalent and disabling disease that affects a significant proportion of the global population. Urine-derived stem cells (USCs) have shown great prospects in the treatment of OA, but there is no study that has compared them with traditional stem cells.

PURPOSE

This study aimed to compare the therapeutic efficacy and mechanisms of USCs and adipose-derived stem cells (ADSCs) for OA treatment.

STUDY DESIGN

Controlled laboratory study.

METHODS

We compared the biological properties of USCs and ADSCs using CCK-8, colony formation, EdU, adhesion, and apoptosis assays. We evaluated the protective effects of USCs and ADSCs on IL-1β-treated OA chondrocytes by chemical staining, immunofluorescence, and Western blotting. We assessed the effects of USCs and ADSCs on chondrocyte autophagy by transmission electron microscopy, immunofluorescence, and Western blotting. We also compared the therapeutic efficacy of intra-articular injections of USCs and ADSCs by gross, histological, micro-computed tomography, and immunohistochemical analyses in an OA rat model induced by anterior cruciate ligament transection.

RESULTS

USCs showed higher proliferation, colony formation, DNA synthesis, adhesion, and anti-apoptotic abilities than ADSCs. Both USCs and ADSCs increased the expression of cartilage-specific proteins and decreased the expression of matrix degradation-related proteins and inflammatory factors in OA chondrocytes. USCs had a greater advantage in suppressing MMP-13 and inflammatory factors than ADSCs. Both USCs and ADSCs enhanced autophagy in OA chondrocytes, with USCs being more effective than ADSCs. The autophagy inhibitor 3-MA reduced the enhanced autophagy and protective effects of USCs and ADSCs on OA chondrocytes.

CONCLUSION

To our knowledge, this is the first study to explore the efficacy of USCs in the treatment of knee OA and to compare them with ADSCs. Considering the superior properties of USCs in terms of noninvasive acquisition, a high cost-benefit ratio, and low ethical concerns, our study suggests that they may be a more promising therapeutic option than ADSCs for OA treatment under rigorous regulatory pathways.

CLINICAL RELEVANCE

USCs may be a superior cell source for stem cells to treat knee OA, and this study strengthens the evidence for the application of USCs.

Advancements in diabetic foot ulcer research: Focus on mesenchymal stem cells and their exosomes

Diabetes represents a widely acknowledged global public health concern. Diabetic foot ulcer (DFU) stands as one of the most severe complications of diabetes, its occurrence imposing a substantial economic burden on patients, profoundly impacting their quality of life. Despite the deepening comprehension regarding the pathophysiology and cellular as well as molecular responses of DFU, the current therapeutic arsenal falls short of efficacy, failing to offer a comprehensive remedy for deep-seated chronic wounds and microvascular occlusions. Conventional treatments merely afford symptomatic alleviation or retard the disease's advancement, devoid of the capacity to effectuate further restitution of compromised vasculature and nerves. An escalating body of research underscores the prominence of mesenchymal stem cells (MSCs) owing to their paracrine attributes and anti-inflammatory prowess, rendering them a focal point in the realm of chronic wound healing. Presently, MSCs have been validated as a highly promising cellular therapeutic approach for DFU, capable of effectuating cellular repair, epithelialization, granulation tissue formation, and neovascularization by means of targeted differentiation, angiogenesis promotion, immunomodulation, and paracrine activities, thereby fostering wound healing. The secretome of MSCs comprises cytokines, growth factors, chemokines, alongside exosomes harboring mRNA, proteins, and microRNAs, possessing immunomodulatory and regenerative properties. The present study provides a systematic exposition on the etiology of DFU and elucidates the intricate molecular mechanisms and diverse functionalities of MSCs in the context of DFU treatment, thereby furnishing pioneering perspectives aimed at harnessing the therapeutic potential of MSCs for DFU management and advancing wound healing processes.

Pharmacokinetic characteristics of mesenchymal stem cells in translational challenges

Over the past two decades, mesenchymal stem/stromal cell (MSC) therapy has made substantial strides, transitioning from experimental clinical applications to commercial products. MSC therapies hold considerable promise for treating refractory and critical conditions such as acute graft-versus-host disease, amyotrophic lateral sclerosis, and acute respiratory distress syndrome. Despite recent successes in clinical and commercial applications, MSC therapy still faces challenges when used as a commercial product. Current detection methods have limitations, leaving the dynamic biodistribution, persistence in injured tissues, and ultimate fate of MSCs in patients unclear. Clarifying the relationship between the pharmacokinetic characteristics of MSCs and their therapeutic effects is crucial for patient stratification and the formulation of precise therapeutic regimens. Moreover, the development of advanced imaging and tracking technologies is essential to address these clinical challenges. This review provides a comprehensive analysis of the kinetic properties, key regulatory molecules, different fates, and detection methods relevant to MSCs and discusses concerns in evaluating MSC druggability from the perspective of integrating pharmacokinetics and efficacy. A better understanding of these challenges could improve MSC clinical efficacy and speed up the introduction of MSC therapy products to the market.

miR-483-5p-Containing exosomes treatment ameliorated deep vein thrombosis‑induced inflammatory response

Peripheral vascular condition, known as deep vein thrombosis (DVT), is a common ailment that may lead to deadly pulmonary embolism. Inflammation is closely connected to venous thrombosis, which results in blood stasis, leading to ischemia and hypoxia, as indicated by research. The objective of this research was to investigate the mechanism by which exosomes derived from adipose stem cells (ADSCs) prevent deep vein thrombosis. Our data showed that Exo-483 effectively reduced the thrombus weight in DVT rats by intravenous injection. Exo-483 decreased the expression of tissue factor (TF) protein, the influx of inflammatory cells into the thrombosed vein wall, and the levels of cytokines in the serum. Furthermore, Exo-483 suppressed the expression of Mitogen-activated protein kinase 1 (MAPK1) and decreased the expression of NLRP3 inflammasomes. In an oxygen-glucose deprivation (OGD) cell model, the tube-forming and migratory abilities of primary human umbilical vein endothelial cells (HUVEC) and EA.hy926 cells were suppressed by Exo-483 pretreatment.Exo-483 is also linked to regulating Dynamin-related protein 1 (DRP1) production downstream of MAPK1.By decreasing the mitochondrial localization and phosphorylation at the S616 site of DRP1, it diminishes the expression of NLRP3 inflammasomes. Moreover, according to Bioinformatics analysis, miR-483-5p was anticipated to target MAPK1. The research conducted by our team revealed that the miR-483-5p exosome derived from ADSCs exhibited anti-inflammatory properties through the modulation of downstream DRP1-NLRP3 expression by targeting MAPK1.The findings of this research propose that miR-483-5p may be regarded as an innovative treatment target for DVT.

Exosomal miRNA-21 derived from umbilical cord mesenchymal stem cells inhibits microglial overactivation to counteract nerve damage

BACKGROUND

Traumatic brain injury (TBI) is a major cause of neurological disability, and current treatments have limited effectiveness. Recent studies have emphasized the potential of exosomes derived from umbilical cord mesenchymal stem cells (UC-MSCs-Exo) in TBI treatment, but the molecular mechanisms underlying their therapeutic effects are not fully understood.

METHODS AND RESULTS

In this study, UC-MSCs-Exo was isolated using ultracentrifugation and intraventricularly injected to TBI rat model. The neurofunctional motor function of the rats was evaluated using the modified neurological severity score (mNSS), and the activation of microglia was assessed through immunofluorescence detection of IBA1 expression levels. Additionally, we established an in vitro neuroinflammatory model using BV2 microglia to investigate the effects of UC-MSCs-Exo and miRNA-21. Our findings indicate that UC-MSCs-Exo promote neurological recovery in TBI rats and inhibit excessive microglia activation. Furthermore, UC-MSCs-Exo highly expresses miRNA-21 and inhibited the proliferation, migration, and release of inflammatory mediators of BV2 microglia by transporting miRNA-21.

CONCLUSIONS

The present study suggests that the promotion of neurological recovery in TBI rats by UC-MSCs-Exo may be attributed to the inhibition of excessive microglia activation through miRNA-21.

Repair of spinal cord injury by bone marrow mesenchymal stem cell-derived exosomes: a systematic review and meta-analysis based on rat models

Objective

This study aims to systematically evaluate the efficacy of bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exo) in improving spinal cord injury (SCI) to mitigate the risk of translational discrepancies from animal experiments to clinical applications.

Methods

We conducted a comprehensive literature search up to March 2024 using PubMed, Embase, Web of Science, and Scopus databases. Two researchers independently screened the literature, extracted data, and assessed the quality of the studies. Data analysis was performed using STATA16 software.

Results

A total of 30 studies were included. The results indicated that BMSCs-Exo significantly improved the BBB score in SCI rats (WMD = 3.47, 95% CI [3.31, 3.63]), inhibited the expression of the pro-inflammatory cytokine TNF-α (SMD = -3.12, 95% CI [-3.57, -2.67]), and promoted the expression of anti-inflammatory cytokines IL-10 (SMD = 2.76, 95% CI [1.88, 3.63]) and TGF-β (SMD = 3.89, 95% CI [3.02, 4.76]). Additionally, BMSCs-Exo significantly reduced apoptosis levels (SMD = -4.52, 95% CI [-5.14, -3.89]), promoted the expression of axonal regeneration markers NeuN cells/field (SMD = 3.54, 95% CI [2.65, 4.42]), NF200 (SMD = 4.88, 95% CI [3.70, 6.05]), and the number of Nissl bodies (SMD = 1.89, 95% CI [1.13, 2.65]), and decreased the expression of astrogliosis marker GFAP (SMD = -5.15, 95% CI [-6.47, -3.82]). The heterogeneity among studies was primarily due to variations in BMSCs-Exo transplantation doses, with efficacy increasing with higher doses.

Conclusion

BMSCs-Exo significantly improved motor function in SCI rats by modulating inflammatory responses, reducing apoptosis, inhibiting astrogliosis, and promoting axonal regeneration. However, the presence of selection, performance, and detection biases in current animal experiments may undermine the quality of evidence in this study.

Stem cell therapeutics and gene therapy for neurologic disorders

Rapid advances in biological knowledge and technological innovation have greatly advanced the fields of stem cell and gene therapies to combat a broad spectrum of neurologic disorders. Researchers are currently exploring a variety of stem cell types (e.g., embryonic, progenitor, induced pluripotent) and various transplantation strategies, each with its own advantages and drawbacks. Similarly, various gene modification techniques (zinc finger, TALENs, CRISPR-Cas9) are employed with various delivery vectors to modify underlying genetic contributors to neurologic disorders. While these two individual fields continue to blaze new trails, it is the combination of these technologies which enables genetically engineered stem cells and vastly increases investigational and therapeutic opportunities. The capability to culture and expand stem cells outside the body, along with their potential to correct genetic abnormalities in patient-derived cells or enhance cells with extra gene products, unleashes the full biological potential for innovative, multifaceted approaches to treat complex neurological disorders. In this review, we provide an overview of stem cell and gene therapies in the context of neurologic disorders, highlighting recent advances and current shortcomings, and discuss prospects for future therapies in clinical settings.

Different origin-derived exosomes and their clinical advantages in cancer therapy

Exosomes, as a class of small extracellular vesicles closely related to the biological behavior of various types of tumors, are currently attracting research attention in cancer diagnosis and treatment. Regarding cancer diagnosis, the stability of their membrane structure and their wide distribution in body fluids render exosomes promising biomarkers. It is expected that exosome-based liquid biopsy will become an important tool for tumor diagnosis in the future. For cancer treatment, exosomes, as the "golden communicators" between cells, can be designed to deliver different drugs, aiming to achieve low-toxicity and low-immunogenicity targeted delivery. Signaling pathways related to exosome contents can also be used for safer and more effective immunotherapy against tumors. Exosomes are derived from a wide range of sources, and exhibit different biological characteristics as well as clinical application advantages in different cancer therapies. In this review, we analyzed the main sources of exosomes that have great potential and broad prospects in cancer diagnosis and therapy. Moreover, we compared their therapeutic advantages, providing new ideas for the clinical application of exosomes.

Therapeutic Effects of Engineered Exosomes from RAW264.7 Cells Overexpressing hsa-let-7i-5p against Sepsis in Mice-A Comparative Study with Human Placenta-Derived Mesenchymal Stem Cell Exosomes

This study compared the therapeutic effects of engineered exosomes derived from RAW264.7 cells overexpressing hsa-let-7i-5p (engineered exosomes) to exosomes from human placenta-derived mesenchymal stem cells (hpMSC exosomes) against sepsis-induced acute lung injury. Adult male C57BL/6 mice were divided into lipopolysaccharide (LPS), LPS plus engineered exosome (LEExo), or LPS plus hpMSC exosome (LMExo) groups, alongside control groups. The results showed that lung injury scores (based on pathohistological characteristics) and the levels of lung function alterations, tissue edema, and leukocyte infiltration in LEExo and LMExo groups were comparable and significantly lower than in the LPS group (all p < 0.05). Furthermore, the levels of inflammation (nuclear factor-κB activation, cytokine upregulation), macrophage activation (hypoxia-inducible factor-1α activation, M1 phase polarization), oxidation, and apoptosis were diminished in LEExo and LMExo groups compared to the LPS group (all p < 0.05). Inhibition of hsa-let-7i-5p attenuated the therapeutic effects of both engineered and hpMSC exosomes. These findings underscore the potent therapeutic capacity of engineered exosomes enriched with hsa-let-7i-5p and their potential as an alternative to hpMSC exosomes for sepsis treatment. Continued research into the mechanisms of action and optimization of engineered exosomes could pave the way for their future clinical application.

Understanding molecular characteristics of extracellular vesicles derived from different types of mesenchymal stem cells for therapeutic translation

Mesenchymal stem cells (MSCs) have been studied for decades as candidates for cellular therapy, and their secretome, including secreted extracellular vesicles (EVs), has been identified to contribute significantly to regenerative and reparative functions. Emerging evidence has suggested that MSC-EVs alone, could be used as therapeutics that emulate the biological function of MSCs. However, just as with MSCs, MSC-EVs have been shown to vary in composition, depending on the tissue source of the MSCs as well as the protocols employed in culturing the MSCs and obtaining the EVs. Therefore, the importance of careful choice of cell sources and culture environments is receiving increasing attention. Many factors contribute to the therapeutic potential of MSC-EVs, including the source tissue, isolation technique, and culturing conditions. This review illustrates the molecular landscape of EVs derived from different types of MSC cells along with culture strategies. A thorough analysis of publicly available omic datasets was performed to advance the precision understanding of MSC-EVs with unique tissue source-dependent molecular characteristics. The tissue-specific protein and miRNA-driven Reactome ontology analysis was used to reveal distinct patterns of top Reactome ontology pathways across adipose, bone marrow, and umbilical MSC-EVs. Moreover, a meta-analysis assisted by an AI technique was used to analyze the published literature, providing insights into the therapeutic translation of MSC-EVs based on their source tissues.

Platelet-rich plasma-derived extracellular vesicles improve liver cirrhosis in mice

INTRODUCTION

Cirrhosis remains a significant clinical challenge due to its poor prognosis and limited treatment options, creating a high unmet medical need for the development of novel therapies. In this study, we analyzed the effects of a novel approach to treat cirrhosis using platelet-rich plasma-derived extracellular vesicles (PRPEV) in mice.

METHODS

PRPEV were collected from platelet-rich plasma using ultrafiltration, and their proteomes were analyzed. The carbon tetrachloride (CCl4)-induced cirrhosis model of mice was used to evaluate the effect of PRPEV administration and compared with the control group (n = 8). In vitro and in vivo mechanistic analyses of PRPEV administration were confirmed using real time-PCR and immunostaining.

RESULTS

Gene ontology analysis based on the proteome revealed that PRPEV contain many factors associated with EV and immune responses. In vitro, PRPEV polarize macrophages into an anti-inflammatory phenotype. Following PRPEV administration, there was a decrease in serum alanine aminotransferase levels and reduction in liver fibrosis, while mRNA levels of regenerative factors were upregulated and transforming growth factor β-1 was downregulated. Furthermore, the number of anti-inflammatory macrophages in the liver increased.

CONCLUSIONS

PRPEV may contribute to hepatocyte proliferation, anti-inflammation, and anti-fibrogenesis in the liver. This novel concept paves the way for cirrhosis treatment.

Unlocking the Potential of Extracellular Vesicles as the Next Generation Therapy: Challenges and Opportunities

BACKGROUND

Mesenchymal stem cells (MSCs) have undergone extensive investigation for their potential therapeutic applications, primarily attributed to their paracrine activity. Recently, researchers have been exploring the therapeutic potential of extracellular vesicles (EVs) released by MSCs.

METHODS

MEDLINE/PubMed and Google scholar databases were used for the selection of literature. The keywords used were mesenchymal stem cells, extracellular vesicles, clinical application of EVs and challenges EVs production.

RESULTS

These EVs have demonstrated robust capabilities in transporting intracellular cargo, playing a critical role in facilitating cell-to-cell communication by carrying functional molecules, including proteins, RNA species, DNAs, and lipids. Utilizing EVs as an alternative to stem cells offers several benefits, such as improved safety, reduced immunogenicity, and the ability to traverse biological barriers. Consequently, EVs have emerged as an increasingly attractive option for clinical use.

CONCLUSION

From this perspective, this review delves into the advantages and challenges associated with employing MSC-EVs in clinical settings, with a specific focus on their potential in treating conditions like lung diseases, cancer, and autoimmune disorders.

Mesenchymal Stromal Cells: New Generation Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which has a high recurrence rate and is incurable due to a lack of effective treatment. Mesenchymal stromal cells (MSCs) are a class of pluripotent stem cells that have recently received a lot of attention due to their strong self-renewal ability and immunomodulatory effects, and a large number of experimental and clinical models have confirmed the positive therapeutic effect of MSCs on IBD. In preclinical studies, MSC treatment for IBD relies on MSCs paracrine effects, cell-to-cell contact, and its mediated mitochondrial transfer for immune regulation. It also plays a therapeutic role in restoring the intestinal mucosal barrier through the homing effect, regulation of the intestinal microbiome, and repair of intestinal epithelial cells. In the latest clinical trials, the safety and efficacy of MSCs in the treatment of IBD have been confirmed by transfusion of autologous or allogeneic bone marrow, umbilical cord, and adipose MSCs, as well as their derived extracellular vesicles. However, regarding the stable and effective clinical use of MSCs, several concerns emerge, including the cell sources, clinical management (dose, route and frequency of administration, and pretreatment of MSCs) and adverse reactions. This article comprehensively summarizes the effects and mechanisms of MSCs in the treatment of IBD and its advantages over conventional drugs, as well as the latest clinical trial progress of MSCs in the treatment of IBD. The current challenges and future directions are also discussed. This review would add knowledge into the understanding of IBD treatment by applying MSCs.

Stem Cell-Derived Extracellular Vesicles: Promising Therapeutic Opportunities for Diabetic Wound Healing

Wound healing is a sophisticated and orderly process of cellular interactions in which the body restores tissue architecture and functionality following injury. Healing of chronic diabetic wounds is difficult due to impaired blood circulation, a reduced immune response, and disrupted cellular repair mechanisms, which are often associated with diabetes. Stem cell-derived extracellular vesicles (SC-EVs) hold the regenerative potential, encapsulating a diverse cargo of proteins, RNAs, and cytokines, presenting a safe, bioactivity, and less ethical issues than other treatments. SC-EVs orchestrate multiple regenerative processes by modulating cellular communication, increasing angiogenesis, and promoting the recruitment and differentiation of progenitor cells, thereby potentiating the reparative milieu for diabetic wound healing. Therefore, this review investigated the effects and mechanisms of EVs from various stem cells in diabetic wound healing, as well as their limitations and challenges. Continued exploration of SC-EVs has the potential to revolutionize diabetic wound care.

Advances in natural and synthetic macromolecules with stem cells and extracellular vesicles for orthopedic disease treatment

Serious orthopedic disorders resulting from myriad diseases and impairments continue to pose a considerable challenge to contemporary clinical care. Owing to its limited regenerative capacity, achieving complete bone tissue regeneration and complete functional restoration has proven challenging with existing treatments. By virtue of cellular regenerative and paracrine pathways, stem cells are extensively utilized in the restoration and regeneration of bone tissue; however, low survival and retention after transplantation severely limit their therapeutic effect. Meanwhile, biomolecule materials provide a delivery platform that improves stem cell survival, increases retention, and enhances therapeutic efficacy. In this review, we present the basic concepts of stem cells and extracellular vesicles from different sources, emphasizing the importance of using appropriate expansion methods and modification strategies. We then review different types of biomolecule materials, focusing on their design strategies. Moreover, we summarize several forms of biomaterial preparation and application strategies as well as current research on biomacromolecule materials loaded with stem cells and extracellular vesicles. Finally, we present the challenges currently impeding their clinical application for the treatment of orthopedic diseases. The article aims to provide researchers with new insights for subsequent investigations.

Human Placental Mesenchymal Stem Cells-Exosomes Alleviate Endothelial Barrier Dysfunction via Cytoskeletal Remodeling through hsa-miR-148a-3p/ROCK1 Pathway

Background

Endothelial barrier disruption of human pulmonary vascular endothelial cells (HPVECs) is an important pathogenic factor for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Mesenchymal stem cells-exosome (MSCs-Exo) represents an ideal carrier for cell-free therapy. The therapeutic implication and underlying mechanism of human placental MSCs-Exo (HPMSCs-Exo) in ALI/ARDS need to be further explored.

Materials and Methods

HPMSCs-Exo was extracted from HPMSCs and characterized. Then, the therapeutic effects of exosomes were evaluated in ALI mice and HPVECs. RNA-sequencing was applied to reveal the miRNA profile of HPMSCs-Exo and differentially expressed genes (DEGs) in HPMSCs-Exo-pretreated HPVECs. The targets of miRNAs were predicted by bioinformatics methods and correlated to DEGs. Finally, the role of hsa-miR-148a-3p/ROCK1 pathway in HPVECs has been further discussed.

Results

The results showed that HPMSCs-Exo could downregulate Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), upregulate the expression of zonula occludens-1 (ZO-1) and F-actin, promote HPVECs migration and tube formation, reduce cytoskeletal disorders and cell permeability, and thus improve ALI/ARDS. RNA-sequencing revealed the DEGs were mainly enriched in cell junction, angiogenesis, inflammation, and energy metabolism. HPMSCs-Exo contains multiple miRNAs which are associated with cytoskeletal function; the expression abundance of hsa-miR-148a-3p is the highest. Bioinformatic analysis identified ROCK1 as a target of hsa-miR-148a-3p. The overexpression of hsa-miR-148a-3p in HPMSCs-Exo promoted the migration and tube formation of HPVECs and reduced ROCK1 expression. However, the overexpression of ROCK1 on HPVECs reduced the therapeutic effect of HPMSCs-Exo.

Conclusions

HPMSCs-Exo represents a protective regimen against endothelial barrier disruption of HPVECs in ALI/ARDS, and the hsa-miR-148a-3p/ROCK1 pathway plays an important role in this therapeutics implication.

Extracellular vesicles derived from M2-like macrophages alleviate acute lung injury in a miR-709-mediated manner

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is characterised by an uncontrolled inflammatory response, and current treatment strategies have limited efficacy. Although the protective effect of M2-like macrophages (M2φ) and their extracellular vesicles (EVs) has been well-documented in other inflammatory diseases, the role of M2φ-derived EVs (M2φ-EVs) in the pathogenesis of ALI/ARDS remains poorly understood. The present study utilised a mouse model of lipopolysaccharide-induced ALI to first demonstrate a decrease in endogenous M2-like alveolar macrophage-derived EVs. And then, intratracheal instillation of exogenous M2φ-EVs from the mouse alveolar macrophage cell line (MH-S) primarily led to a take up by alveolar macrophages, resulting in reduced lung inflammation and injury. Mechanistically, the M2φ-EVs effectively suppressed the pyroptosis of alveolar macrophages and inhibited the release of excessive cytokines such as IL-6, TNF-α and IL-1β both in vivo and in vitro, which were closely related to NF-κB/NLRP3 signalling pathway inhibition. Of note, the protective effect of M2φ-EVs was partly mediated by miR-709, as evidenced by the inhibition of miR-709 expression in M2φ-EVs mitigated their protective effect against lipopolysaccharide-induced ALI in mice. In addition, we found that the expression of miR-709 in EVs derived from bronchoalveolar lavage fluid was correlated negatively with disease severity in ARDS patients, indicating its potential as a marker for ARDS severity. Altogether, our study revealed that M2φ-EVs played a protective role in the pathogenesis of ALI/ARDS, partly mediated by miR-709, offering a potential strategy for assessing disease severity and treating ALI/ARDS.

Mesenchymal stem cell-derived exosomes: Characteristics and applications in disease pathology and management

Mesenchymal stem cells (MSCs) possess a role in tissue regeneration and homeostasis because of inherent immunomodulatory capacity and the production of factors that encourage healing. There is substantial evidence that MSCs' therapeutic efficacy is primarily determined by their paracrine function including in cancers. Extracellular vesicles (EVs) are basic paracrine effectors of MSCs that reside in numerous bodily fluids and cell homogenates and play an important role in bidirectional communication. MSC-derived EVs (MSC-EVs) offer a wide range of potential therapeutic uses that exceed cell treatment, while maintaining protocell function and having less immunogenicity. We describe characteristics and isolation methods of MSC-EVs, and focus on their therapeutic potential describing its roles in tissue repair, anti-fibrosis, and cancer with an emphasis on the molecular mechanism and immune modulation and clinical trials. We also explain current understanding and challenges in the clinical applications of MSC-EVs as a cell free therapy.

Engineered exosomes in emerging cell-free therapy

The discovery and use of exosomes ushered in a new era of cell-free therapy. Exosomes are a subgroup of extracellular vesicles that show great potential in disease treatment. Engineered exosomes. with their improved functions have attracted intense interests of their application in translational medicine research. However, the technology of engineering exosomes still faces many challenges which have been the great limitation for their clinical application. This review summarizes the current status of research on engineered exosomes and the difficulties encountered in recent years, with a view to providing new approaches and ideas for future exosome modification and new drug development.

Bioreactor-based stem cell therapy for liver fibrosis

Stem cell therapy, achieved using mesenchymal stem cells (MSCs), has been highlighted for the treatment of liver fibrosis. Infusion into the circulatory system is a traditional application of MSCs; however, this approach is limited by phenotypic drift, stem cell senescence, and vascular embolism. Maintaining the therapeutic phenotype of MSCs while avoiding adverse infusion-related reactions is the key to developing next-generation stem cell therapy technologies. Here, we propose a bioreactor-based MSCs therapy to avoid cell infusion. In this scheme, 5% liver fibrosis serum was used to induce the therapeutic phenotype of MSCs, and a fluid bioreactor carrying a co-culture system of hepatocytes and MSCs was constructed to produce the therapeutic medium. In a rat model of liver fibrosis, the therapeutic medium derived from the bioreactor significantly alleviated liver fibrosis. Therapeutic mechanisms include immune regulation, inhibition of hepatic stellate cell activation, establishment of hepatocyte homeostasis, and recovery of liver stem cell subsets. Overall, the bioreactor-based stem cell therapy (scheme) described here represents a promising new strategy for the treatment of liver fibrosis and will be beneficial for the development of 'cell-free' stem cell therapy.

Wireless Electric Cues Mediate Autologous DPSC-Loaded Conductive Hydrogel Microspheres to Engineer the Immuno-Angiogenic Niche for Homologous Maxillofacial Bone Regeneration

Stem cell therapy serves as an effective treatment for bone regeneration. Nevertheless, stem cells from bone marrow and peripheral blood are still lacking homologous properties. Dental pulp stem cells (DPSCs) are derived from neural crest, in coincidence with maxillofacial tissues, thus attracting great interest in in situ maxillofacial regenerative medicine. However, insufficient number and heterogenous alteration of seed cells retard further exploration of DPSC-based tissue engineering. Electric stimulation has recently attracted great interest in tissue regeneration. In this study, a novel DPSC-loaded conductive hydrogel microspheres integrated with wireless electric generator is fabricated. Application of exogenous electric cues can promote stemness maintaining and heterogeneity suppression for unpredictable differentiation of encapsulated DPSCs. Further investigations observe that electric signal fine-tunes regenerative niche by improvement on DPSC-mediated paracrine pattern, evidenced by enhanced angiogenic behavior and upregulated anti-inflammatory macrophage polarization. By wireless electric stimulation on implanted conductive hydrogel microspheres, loaded DPSCs facilitates the construction of immuno-angiogenic niche at early stage of tissue repair, and further contributes to advanced autologous mandibular bone defect regeneration. This novel strategy of DPSC-based tissue engineering exhibits promising translational and therapeutic potential for autologous maxillofacial tissue regeneration.

Application of dental pulp stem cells for bone regeneration

Bone defects resulting from severe trauma, tumors, inflammation, and other factors are increasingly prevalent. Stem cell-based therapies have emerged as a promising alternative. Dental pulp stem cells (DPSCs), sourced from dental pulp, have garnered significant attention owing to their ready accessibility and minimal collection-associated risks. Ongoing investigations into DPSCs have revealed their potential to undergo osteogenic differentiation and their capacity to secrete a diverse array of ontogenetic components, such as extracellular vesicles and cell lysates. This comprehensive review article aims to provide an in-depth analysis of DPSCs and their secretory components, emphasizing extraction techniques and utilization while elucidating the intricate mechanisms governing bone regeneration. Furthermore, we explore the merits and demerits of cell and cell-free therapeutic modalities, as well as discuss the potential prospects, opportunities, and inherent challenges associated with DPSC therapy and cell-free therapies in the context of bone regeneration.

The Immunoregulatory and Regenerative Potential of Activated Human Stem Cell Secretome Mitigates Acute-on-Chronic Liver Failure in a Rat Model

Acute-on-chronic liver failure (ACLF) is a syndrome marked by sudden liver function decline and multiorgan failure, predominantly acute kidney injury (AKY), in patients with chronic liver disease. Unregulated inflammation is a hallmark of ACLF; however, the key drivers of ACLF are not fully understood. This study explores the therapeutic properties of human mesenchymal stem cell (MSC) secretome, particularly focusing on its enhanced anti-inflammatory and pro-regenerative properties after the in vitro preconditioning of the cells. We evaluated the efficacy of the systemic administration of MSC secretome in preventing liver failure and AKI in a rat ACLF model where chronic liver disease was induced using by the administration of porcine serum, followed by D-galN/LPS administration to induce acute failure. After ACLF induction, animals were treated with saline (ACLF group) or MSC-derived secretome (ACLF-secretome group). The study revealed that MSC-secretome administration strongly reduced liver histological damage in the ACLF group, which was correlated with higher hepatocyte proliferation, increased hepatic and systemic anti-inflammatory molecule levels, and reduced neutrophil and macrophage infiltration. Additionally, renal examination revealed that MSC-secretome treatment mitigated tubular injuries, reduced apoptosis, and downregulated injury markers. These improvements were linked to increased survival rates in the ACLF-secretome group, endorsing MSC secretomes as a promising therapy for multiorgan failure in ACLF.

Trans-Arterial Stem Cell Injection (TASI): The Role of Interventional Radiology in Regenerative Medicine

Regenerative medicine is taking a step forward in treating multiple diseases. The possibility of renewing damaged tissues with stem cells has become a topic of interest in recent decades. Still a relatively new research topic, many issues in this discipline are being addressed, from cell culturing to the study of different graft materials, and, moreover, cell delivery. For instance, direct intravenous injection has a big downfall regarding its lack of precision and poorly targeted treatment. Trans-arterial and direct percutaneous infusion to the aimed tissue/organ are both considered ideal for reaching the desired region but require image guidance to be performed safely and precisely. In this context, interventional radiology becomes pivotal for providing different cell delivery possibilities in every case. In this review, we analyze different basic stem cell therapy concepts and the current and future role of interventional radiology with a focus on trans-arterial delivery.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes Rescue Testicular Aging

BACKGROUND

Testicular aging is associated with diminished fertility and certain age-related ailments, and effective therapeutic interventions remain elusive. Here, we probed the therapeutic efficacy of exosomes derived from human umbilical cord mesenchymal stem cells (hUMSC-Exos) in counteracting testicular aging.

METHODS

We employed a model of 22-month-old mice and administered intratesticular injections of hUMSC-Exos. Comprehensive analyses encompassing immunohistological, transcriptomic, and physiological assessments were conducted to evaluate the effects on testicular aging. Concurrently, we monitored alterations in macrophage polarization and the oxidative stress landscape within the testes. Finally, we performed bioinformatic analysis for miRNAs in hUMSC-Exos.

RESULTS

Our data reveal that hUMSC-Exos administration leads to a marked reduction in aging-associated markers and cellular apoptosis while promoting cellular proliferation in aged testis. Importantly, hUMSC-Exos facilitated the restoration of spermatogenesis and elevated testosterone synthesis in aged mice. Furthermore, hUMSC-Exos could attenuate inflammation by driving the phenotypic shift of macrophages from M1 to M2 and suppress oxidative stress by reduced ROS production. Mechanistically, these efficacies against testicular aging may be mediated by hUMSC-Exos miRNAs.

CONCLUSIONS

Our findings suggest that hUMSC-Exos therapy presents a viable strategy to ameliorate testicular aging, underscoring its potential therapeutic significance in managing testicular aging.

Mesenchymal stem cell-derived exosomes in myocardial infarction: Therapeutic potential and application

Myocardial infarction refers to the irreversible impairment of cardiac function resulting from the permanent loss of numerous cardiomyocytes and the formation of scar tissue. This condition is caused by acute and persistent inadequate blood supply to the heart's arteries. In the treatment of myocardial infarction, Mesenchymal stem cells (MSCs) play a crucial role because of their powerful therapeutic effects. These effects primarily stem from the paracrine secretion of multiple factors by MSCs, with exosome-carried microRNAs being the most effective component in promoting cardiac function recovery after infarction. Exosome therapy has emerged as a promising cell-free treatment for myocardial infarction as a result of its relatively simple composition, low immunogenicity and controlled transplantation dose. Despite these advantages, maintaining the stability of exosomes after transplantation and enhancing their targeting effect remain significant challenges in clinical applications. In recent developments, several approaches have been designed to optimize exosome therapy. These include enhancing exosome retention, improving their ability to target specific effects, pretreating MSC-derived exosomes and employing transgenic MSC-derived exosomes. This review primarily focuses on describing the biological characteristics of exosomes, their therapeutic potential and their application in treating myocardial infarction.

Stem cell-derived exosomes for traumatic spinal cord injury: a systematic review and network meta-analysis based on a rat model

BACKGROUND AIMS

Exosome therapy for traumatic spinal cord injury (TSCI) is a current research hotspot, but its therapeutic effect and the best source of stem cells for exosomes are unclear.

METHODS

The Web of Science, PubMed, Embase, Cochrane, and Scopus databases were searched from inception to March 28, 2023. Literature screening, data extraction and risk of bias assessment were performed independently by two investigators.

RESULTS

A total of 40 studies were included for data analysis. The findings of our traditional meta-analysis indicate that exosomes derived from stem cells significantly improve the motor function of TSCI at various time points (1 week: weighted mean difference [WMD] = 1.58, 95% confidence interval [CI] 0.87-2.30] 2 weeks: WMD = 3.12, 95% CI 2.64-3.61; 3 weeks: WMD = 4.44, 95% CI 3.27-5.60; 4 weeks: WMD = 4.54, 95% CI 3.42-5.66). Four kinds of stem cell-derived exosomes have been studied: bone marrow mesenchymal stem cells, adipose mesenchymal stem cells, umbilical cord mesenchymal stem cells and neural stem cells. The results of the network meta-analysis showed that there was no significant statistical difference in the therapeutic effect among the exosomes derived from four kinds of stem cells at different treatment time points. Although exosomes derived from bone marrow mesenchymal stem cells are the current research focus, exosomes derived from neural stem cells have the most therapeutic potential and should become the focus of future attention.

CONCLUSIONS

The exosomes derived from stem cells can significantly improve the motor function of TSCI rats, and the exosomes derived from neural stem cells have the most therapeutic potential. However, the lower evidence quality of animal studies limits the reliability of experimental results, emphasizing the need for more high-quality, direct comparative studies to explore the therapeutic efficacy of exosomes and the best source of stem cells.

Strategies to improve the therapeutic efficacy of mesenchymal stem cell-derived extracellular vesicle (MSC-EV): a promising cell-free therapy for liver disease

Liver disease has emerged as a significant worldwide health challenge due to its diverse causative factors and therapeutic complexities. The majority of liver diseases ultimately progress to end-stage liver disease and liver transplantation remains the only effective therapy with the limitations of donor organ shortage, lifelong immunosuppressants and expensive treatment costs. Numerous pre-clinical studies have revealed that extracellular vesicles released by mesenchymal stem cells (MSC-EV) exhibited considerable potential in treating liver diseases. Although natural MSC-EV has many potential advantages, some characteristics of MSC-EV, such as heterogeneity, uneven therapeutic effect, and rapid clearance in vivo constrain its clinical translation. In recent years, researchers have explored plenty of ways to improve the therapeutic efficacy and rotation rate of MSC-EV in the treatment of liver disease. In this review, we summarized current strategies to enhance the therapeutic potency of MSC-EV, mainly including optimization culture conditions in MSC or modifications of MSC-EV, aiming to facilitate the development and clinical application of MSC-EV in treating liver disease.

Advancements in engineered mesenchymal stem cell exosomes for chronic lung disease treatment

Chronic lung diseases include an array of conditions that impact airways and lung structures, leading to considerable societal burdens. Mesenchymal stem cells (MSCs) and their exosomes (MSC-exos) can be used for cell therapy and exhibit a diverse spectrum of anti-inflammatory, antifibrotic, and immunomodulatory properties. Engineered MSC-exos possesses enhanced capabilities for targeted drug delivery, resulting in more potent targeting effects. Through various engineering modifications, these exosomes can exert many biological effects, resulting in specific therapeutic outcomes for many diseases. Moreover, engineered stem cell exosomes may exhibit an increased capacity to traverse physiological barriers and infiltrate protected lesions, thereby exerting their therapeutic effects. These characteristics render them a promising therapeutic agent for chronic pulmonary diseases. This article discusses and reviews the strategies and mechanisms of engineered MSC-exos in the treatment of chronic respiratory diseases based on many studies to provide new solutions for these diseases.

Stem-Cell-Derived Extracellular Vesicles: Unlocking New Possibilities for Treating Diminished Ovarian Reserve and Premature Ovarian Insufficiency

Despite advancements in assisted reproductive technology (ART), achieving successful pregnancy rates remains challenging. Diminished ovarian reserve and premature ovarian insufficiency hinder IVF success-about 20% of in vitro fertilization (IVF) patients face a poor prognosis due to a low response, leading to higher cancellations and reduced birth rates. In an attempt to address the issue of premature ovarian insufficiency (POI), we conducted systematic PubMed and Web of Science research, using keywords "stem cells", "extracellular vesicles", "premature ovarian insufficiency", "diminished ovarian reserve" and "exosomes". Amid the complex ovarian dynamics and challenges like POI, stem cell therapy and particularly the use of extracellular vesicles (EVs), a great potential is shown. EVs trigger paracrine mechanisms via microRNAs and bioactive molecules, suppressing apoptosis, stimulating angiogenesis and activating latent regenerative potential. Key microRNAs influence estrogen secretion, proliferation and apoptosis resistance. Extracellular vesicles present a lot of possibilities for treating infertility, and understanding their molecular mechanisms is crucial for maximizing EVs' therapeutic potential in addressing ovarian disorders and promoting reproductive health.

Beyond Canine Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells Transplantation: An Update on Their Secretome Characterization and Applications

A dog is a valuable animal model and concomitantly a pet for which advanced therapies are increasingly in demand. The characteristics of mesenchymal stem/stromal cells (MSCs) have made cell therapy more clinically attractive. During the last decade, research on the MSC therapeutic effectiveness has demonstrated that tissue regeneration is primarily mediated by paracrine factors, which are included under the name of secretome. Secretome is a mixture of soluble factors and a variety of extracellular vesicles. The use of secretome for therapeutic purposes could have some advantages compared to cell-based therapies, such as lower immunogenicity and easy manufacturing, manipulation, and storage. The conditioned medium and extracellular vesicles derived from MSCs have the potential to be employed as new treatments in veterinary medicine. This review provides an update on the state-of-the-art characterization and applications of canine adipose tissue-derived MSC secretome.

Pretreatment of UC-MSCs with IFN-α2 improves treatment of liver fibrosis by recruiting neutrophils

BACKGROUND

The use of umbilical cord mesenchymal stem cells (UC-MSCs) is a burgeoning method for the treatment of liver cirrhosis. However, the secretory phenotype and regulatory ability of UC-MSCs are easily affected by their microenvironment. Ensuring a specific microenvironment to enhance the UC-MSCs phenotype is a potential strategy for improving their therapeutic efficacy. The aim of this study was to explore therapeutic UC-MSCs phenotypes for improving liver fibrosis.

METHODS

RNA-sequencing was used to analyze the response pattern of UC-MSCs after exposure to the serum of cirrhotic patients with HBV. Using immunohistochemistry, quantitative polymerase chain reaction, and immunofluorescence techniques, we evaluated the therapeutic effect of UC-MSCs pretreated with interferon alpha 2 (IFN-α2) (pre-MSCs) in an animal model of cirrhosis. Immunoblotting, ELISA, and other techniques were used to analyze the signaling pathways underlying the IFN-induced changes in UC-MSCs.

RESULTS

UC-MSCs exposed to the serum of patients with hepatitis B-induced cirrhosis showed an enhanced response to type I IFN. The activated type I IFN signal induced the highest secretion of colony-stimulating factor 3 (CSF-3), interleukin (IL)-8, and chemokine (C-C motif) ligand 20 (CCL20) by the UC-MSCs. Pre-MSCs showed a higher therapeutic efficacy than untreated UC-MSCs in an animal model of liver fibrosis. Immunohistochemical analysis revealed that pre-MSCs could recruit neutrophils resulting in an increase in the secretion of matrix metalloprotease 8 that alleviated fibrosis. When neutrophils in animals were depleted, the therapeutic effect of pre-MSCs on fibrosis was inhibited. IFN-α2 altered the secretory phenotype of UC-MSCs by activating phosphorylated signal transducer and activator of transcription 1 and 2 (p-STAT1 and p-STAT2).

CONCLUSIONS

Pre-MSCs exhibited enhanced secretion of CSF-3, IL-8, and CCL20 and recruited neutrophils to alleviate fibrosis. This new strategy can improve cell therapy for liver cirrhosis.

Nano-calcipotriol as a potent anti-hepatic fibrosis agent

Calcipotriol (CAL) has been widely studied as a fibrosis inhibitor and used to treat plaque psoriasis via transdermal administration. The clinical application of CAL to treat liver fibrosis is bottlenecked by its unsatisfactory pharmacokinetics, biodistribution, and side effects, such as hypercalcemia in patients. The exploration of CAL as a safe and effective antifibrotic agent remains a major challenge. Therefore, we rationally designed and synthesized a self-assembled drug nanoparticle encapsulating CAL in its internal hydrophobic core for systematic injection (termed NPs/CAL) and further investigated the beneficial effect of the nanomaterial on liver fibrosis. C57BL/6 mice were used as the animal model, and human hepatic stellate cell line LX-2 was used as the cellular model of hepatic fibrogenesis. Immunofluorescence staining, flow cytometry, western blotting, immunohistochemical staining, and in vitro imaging were used for evaluating the efficacy of NPs/CAL treatment. We found NPs/CAL can be quickly internalized in vitro, thus potently deactivating LX-2 cells. In addition, NPs/CAL improved blood circulation and the accumulation of CAL in liver tissue. Importantly, NPs/CAL strongly contributed to the remission of liver fibrosis without inducing hypercalcemia. Overall, our work identifies a promising paradigm for the development of nanomaterial-based agents for liver fibrosis therapy.