Biodistribution of Intratracheal, Intranasal, and Intravenous Injections of Human Mesenchymal Stromal Cell-Derived Extracellular Vesicles in a Mouse Model for Drug Delivery Studies

Harnessing stem cell-derived exosomes: a promising cell-free approach for spinal cord injury

Spinal cord injury (SCI) is a severe injury to the central nervous system that often results in permanent neurological dysfunction. Current treatments have limited efficacy and face challenges in restoring neurological function after injury. Recently, stem cell-derived exosomes have gained attention as an experimental treatment for SCI due to their unique properties, including superior biocompatibility, minimal immunogenicity and non-tumorigenicity. With their potential as a cell-free therapy, exosomes promote SCI repair by enhancing nerve regeneration, reducing inflammation and stabilizing the blood-spinal cord barrier. This review summarizes advances in stem cell-derived exosome research for SCI over the past years, focusing on their mechanisms and future prospects. Despite their promising therapeutic potential, clinical translation remains challenging due to standardization of exosome isolation protocols, compositional consistency and long-term safety profiles that require further investigation.

Extracellular vesicles as precision therapeutics for psychiatric conditions: targeting interactions among neuronal, glial, and immune networks

The critical role of the immune system in brain function and dysfunction is well recognized, yet development of immune therapies for psychiatric diseases has been slow due to concerns about iatrogenic immune deficiencies. These concerns are emphasized by the lack of objective diagnostic tools in psychiatry. A promise to resolve this conundrum lies in the exploitation of extracellular vesicles (EVs) that are physiologically produced or can be synthetized. EVs regulate recipient cell functions and offer potential for EVs-based therapies. Intranasal EVs administration enables the targeting of specific brain regions and functions, thereby facilitating the design of precise treatments for psychiatric diseases. The development of such therapies requires navigating four dynamically interacting networks: neuronal, glial, immune, and EVs. These networks are profoundly influenced by brain fluid distribution. They are crucial for homeostasis, cellular functions, and intercellular communication. Fluid abnormalities, like edema or altered cerebrospinal fluid (CSF) dynamics, disrupt these networks, thereby negatively impacting brain health. A deeper understanding of the above-mentioned four dynamically interacting networks is vital for creating diagnostic biomarker panels to identify distinct patient subsets with similar neuro-behavioral symptoms. Testing the functional pathways of these biomarkers could lead to new therapeutic tools. Regulatory approval will depend on robust preclinical data reflecting progress in these interdisciplinary areas, which could pave the way for the design of innovative and precise treatments. Highly collaborative interdisciplinary teams will be needed to achieve these ambitious goals.

Intranasal administration of stem cell-derived exosome alleviates cognitive impairment against subarachnoid hemorrhage

INTRODUCTION

Brain damage caused by subarachnoid hemorrhage (SAH) currently lacks effective treatment, leading to stagnation in the improvement of functional outcomes for decades. Recent studies have demonstrated the therapeutic potential of exosomes released from mesenchymal stem cells (MSC), which effectively attenuate neuronal apoptosis and inflammation in neurological diseases. Due to the challenge of systemic dilution associated with intravenous administration, intranasal delivery has emerged as a novel approach for targeting the brain. In this study, we investigate the effects of intranasally administered MSC-derived exosomes in a SAH animal model and elucidate their mode of action.

METHODS

Exosomes were isolated from the cell supernatants of amnion-derived MSC. SAH was induced in 8-week-old Sprague-Dawley rats using an autologous blood prechiasmatic cistern injection model. A total of 1.2 × 1010 particles of exosomes in 200 μL of PBS or PBS alone were intranasally administered immediately and 24 h post-injury. Neurological function was assessed up to 7 days after injury, and histological analysis was performed to evaluate their anti-apoptotic and anti-inflammatory effects. The biodistribution of exosomes was assessed using PET/CT imaging of 64Cu labeled exosome. In vitro analyses were performed using primary glial cells and cell lines to evaluate the anti-inflammatory effects of the exosomes.

RESULTS

Animals treated with exosomes exhibited significant improvement in cognitive function compared with PBS treated animal. Apoptotic cells and inflammation were reduced for the exosome group in the hippocampal CA1 area and in cortex, resulting in better neuronal cell survival. Blood brain barrier permeability was also preserved in the exosome group. Nuclear imaging revealed that exosomes were primarily transferred to the olfactory nerve and cerebrum; furthermore, exosomes were also observed in the trigeminal nerve and brainstem, where exosomes were co-localized with microglia and with endothelial cells. In vitro assessment showed that exosome administration ameliorated inflammation and prevented the death of glial cells.

CONCLUSIONS

MSC-derived exosomes were successfully transferred into the brain through intranasal administration and alleviated brain damage following SAH.

Extracellular vesicles derived from mesenchymal stem cells alleviate depressive-like behavior in a rat model of chronic stress

Depression is a prevalent chronic psychiatric disorder with a growing impact on global health. Current treatments often fail to achieve full remission, highlighting the need for alternative therapeutic strategies. Mesenchymal stem cells (MSCs) have attracted significant interest for their therapeutic potential in neuropsychiatric disorders, primarily due to their capacity to target neuroinflammation. This study aimed to investigate if extracellular vesicles derived from human umbilical MSCs (hucMSCs) promote behavioral beneficial actions in a rat model of chronic unpredictable mild stress (CUMS). We show that a single dose of hucMSCs or their derived EVs (hucMSC-EVs) via the tail vein alleviated depressive-like behavior in rats, reduced markers of neuroinflammation, reduced pro-inflammatory cytokines (IL-1β and TNF-α), and increased the number and dendritic complexity of DCX-positive cells in the dentate gyrus. Proteomic analysis of EVs revealed the presence of proteins involved in modulation of inflammatory processes and cell activation. Our study demonstrates EVs derived from hucMSCs can effectively mitigate depressive symptoms by modulating neuroinflammatory pathways and enhancing neurogenesis. These findings support further exploration of MSC-derived EVs as a novel therapeutic option for neuropsychiatric disorders.

Advances in Tracing Techniques: Mapping the Trajectory of Mesenchymal Stem-Cell-Derived Extracellular Vesicles

Mesenchymal stem-cell-derived extracellular vesicles (MSC-EVs) are nanoscale lipid bilayer vesicles secreted by mesenchymal stem cells. They inherit the parent cell's attributes, facilitating tissue repair and regeneration, promoting angiogenesis, and modulating the immune response, while offering advantages like reduced immunogenicity, straightforward administration, and enhanced stability for long-term storage. These characteristics elevate MSC-EVs as highly promising in cell-free therapy with notable clinical potential. It is critical to delve into their pharmacokinetics and thoroughly elucidate their intracellular and in vivo trajectories. A detailed summary and evaluation of existing tracing strategies are needed to establish standardized protocols. Here, we have summarized and anticipated the research progress of MSC-EVs in various biomedical imaging techniques, including fluorescence imaging, bioluminescence imaging, nuclear imaging (PET, SPECT), tomographic imaging (CT, MRI), and photoacoustic imaging. The challenges and prospects of MSC-EV tracing strategies, with particular emphasis on clinical translation, have been analyzed, with promising solutions proposed.

Intranasal delivery of extracellular vesicles: A promising new approach for treating neurological and respiratory disorders

BACKGROUND

Extracellular vesicles (EVs) are membrane vesicles secreted by all types of cells, including bacteria, animals, and plants. These vesicles contain proteins, nucleic acids, and lipids from their parent cells and can transfer these components between cells. EVs have attracted attention for their potential use in diagnosis and therapy due to their natural properties, such as low immunogenicity, high biocompatibility, and ability to cross the blood-brain barrier. They can also be engineered to carry therapeutic molecules. EVs can be delivered via various routes. The intranasal route is particularly advantageous for delivering them to the central nervous system, making it a promising approach for treating neurological disorders.

SCOPE OF REVIEW

This review delves into the promising potential of intranasally administered EVs-based therapies for various medical conditions, with a particular focus on those affecting the brain and central nervous system. Additionally, the potential use of these therapies for pulmonary conditions, cancer, and allergies is examined, offering a hopeful outlook for the future of medical treatments.

MAJOR CONCLUSIONS

The intranasal administration of EVs offers significant advantages over other delivery methods. By directly delivering EVs to the brain, specifically targeting areas that have been injured, this administration proves to be highly efficient and effective, providing reassurance about the progress in medical treatments. Intranasal delivery is not limited to brain-related conditions. It can also benefit other organs like the lungs and stimulate a mucosal immune response against various pathogens due to the highly vascularized nature of the nasal cavity and airways. Moreover, it has the added benefit of minimizing toxicity to non-targeted organs and allows the EVs to remain longer in the body. As a result, there is a growing emphasis on conducting clinical trials for intranasal administration of EVs, particularly in treating respiratory tract pathologies such as coronavirus disease.

Advancing functional foods: a systematic analysis of plant-derived exosome-like nanoparticles and their health-promoting properties

Plant-derived exosome-like nanoparticles (PDENs), emerging as novel bioactive agents, exhibit significant potential in food science and nutritional health. These nanoparticles, enriched with plant-specific biomolecules such as proteins, lipids, nucleic acids, and secondary metabolites, demonstrate unique cross-species regulatory capabilities, enabling interactions with mammalian cells and gut microbiota. PDENs enhance nutrient bioavailability by protecting sensitive compounds during digestion, modulate metabolic pathways through miRNA-mediated gene regulation, and exhibit anti-inflammatory and antioxidant properties. For instance, grape-derived PDENs reduce plasma triglycerides in high-fat diets, while ginger-derived nanoparticles alleviate colitis by downregulating pro-inflammatory cytokines. Additionally, PDENs serve as natural drug carriers, with applications in delivering therapeutic agents like doxorubicin and paclitaxel. Despite these advancements, challenges remain in standardizing extraction methods (ultracentrifugation, immunoaffinity), ensuring stability during food processing and storage, and evaluating long-term safety. Current research highlights the need for optimizing lyophilization techniques and understanding interactions between PDENs and food matrices. Furthermore, while PDENs show promise in functional food development-such as fortified beverages and probiotic formulations-their clinical translation requires rigorous pharmacokinetic studies and regulatory clarity. This review synthesizes existing knowledge on PDENs' composition, biological activities, and applications, while identifying gaps in scalability, stability, and safety assessments. Future directions emphasize interdisciplinary collaboration to harness PDENs' potential in combating metabolic disorders, enhancing food functionality, and advancing personalized nutrition strategies.

Effects of Hydrogels on Mesenchymal Stem/Stromal Cells Paracrine Activity and Extracellular Vesicles Production

Mesenchymal stem/stromal cells (MSCs) are a valuable source of paracrine factors, as they have a remarkable secretory capacity, and there is a sizeable knowledge base to develop industrial and clinical production protocols. Promising cell-free approaches for tissue regeneration and immunomodulation are driving research towards secretome applications, among which extracellular vesicles (EVs) are steadily gaining attention. However, the manufacturing and application of EVs is limited by insufficient yields, knowledge gaps, and low standardization. Facing these limitations, hydrogels represent a versatile three-dimensional (3D) culture platform that can incorporate extracellular matrix (ECM) components to mimic the natural stem cell environment in vitro; via these niche-mimicking properties, hydrogels can regulate MSCs' morphology, adhesion, proliferation, differentiation and secretion capacities. However, the impact of the hydrogel's architectural, biochemical and biomechanical properties on the production of EVs remains poorly understood, as the field is still in its infancy and the interdependency of culture parameters compromises the comparability of the studies. Therefore, this review summarizes and discusses the reported effects of hydrogel encapsulation and culture on the secretion of MSC-EVs. Considering the effects of cell-material interactions on the overall paracrine activity of MSCs, we identify persistent challenges from low standardization and process control, and outline future paths of research, such as the synergic use of hydrogels and bioreactors to enhance MSC-EV generation.

Mesenchymal stem cell exosome therapy: current research status in the treatment of neurodegenerative diseases and the possibility of reversing normal brain aging

With the exacerbation of the aging population trend, a series of neurodegenerative diseases caused by brain aging have become increasingly common, significantly impacting the daily lives of the elderly and imposing heavier burdens on nations and societies. Brain aging is a complex process involving multiple mechanisms, including oxidative stress, apoptosis of damaged neuronal cells, chronic inflammation, and mitochondrial dysfunction, and research into new therapeutic strategies to delay brain aging has gradually become a research focus in recent years. Mesenchymal stem cells (MSCs) have been widely used in cell therapy due to their functions such as antioxidative stress, anti-inflammation, and tissue regeneration. However, accompanying safety issues such as immune rejection, tumor development, and pulmonary embolism cannot be avoided. Studies have shown that using exosome derived from mesenchymal stem cells (MSC-Exo) for the treatment of neurodegenerative diseases is a safe and effective method. It not only has the therapeutic effects of stem cells but also avoids the risks associated with cell therapy. Therefore, exploring new therapeutic strategies to delay normal brain aging from the mechanism of MSC-Exo in the treatment of neurodegenerative diseases is feasible. This review summarizes the characteristics of MSC-Exo and their clinical progress in the treatment of neurodegenerative diseases, aiming to explore the possibility and potential mechanisms of MSC-Exo in reversing brain aging.

Therapeutic potential of stem cell-derived extracellular vesicles in neurodegenerative diseases associated with cognitive decline

In the central nervous system, cell-to-cell interaction is essential for brain plassticity and repair, and its alteration is critically involved in the development of neurodegenerative diseases. Neural stem cells are a plentiful source of biological signals promoting neuroplasticity and the maintenance of cognitive functions. Extracellular vesicles (EVs) represent an additional strategy for cells to release signals in the surrounding cellular environment or to exchange information among both neighboring and distant cells. In the last years, rising attention has been devoted to the ability of stem cell (SC)-derived EVs to counteract inflammatory and degenerative brain disorders taking advantage of their immunomodulatory capacities and regenerative potential. Here, we review the role of adult neurogenesis impairment in the cognitive decline associated with neurodegenerative diseases and describe the beneficial effects of SC-derived EVs on brain plasticity and repair also discussing the advantages of SC-derived EV administration vs SC transplantation in the treatment of neurodegenerative disorders.

Gold nanomaterials capped with bovine serum albumin for cell and extracellular vesicle imaging

Bovine serum albumin-capped gold nanoclusters (AuNC@BSA) are ionic, ultra-small, and eco-friendly nanomaterials that exhibit red fluorescence emission. Upon modification, these nanomaterials can serve as imaging probes with multimodal functionality. Owing to their nanoscale properties, AuNC@BSA-based nanomaterials can be readily endocytosed by cells for imaging. With the increasing interest in cell therapy, extracellular vesicles (EVs) have attracted considerable attention from researchers; however, effective methods for imaging EVs remain limited. Although several studies have explored imaging strategies for cells and EVs using compounds, nuclear pharmaceuticals, nanoparticles, or genetic constructs, the use of AuNC@BSA-based nanomaterials for labeling EVs and their parental cells has rarely been discussed, with even less attention paid to their multimodal potential. To address this gap, we utilized three types of AuNC@BSA-based derivatives: AuNC@BSA, AuNC@BSA-Gd, and AuNC@BSA-Gd-I. Our findings demonstrate that these derivatives can effectively label both cells and EVs using a simple direct labeling approach, which is particularly notable for EVs, as they typically require more complex labeling procedures. Furthermore, the multimodal potential of labeled cells and EVs was evaluated, revealing their capabilities for multimodal imaging. In summary, this study presents an effective strategy for labeling EVs and their parental cells using multimodal nanomaterials. These findings will contribute to accelerating the development of drug delivery systems, cell- and EV-based therapies, and advanced imaging strategies.

Amniotic fluid-derived stem cells: potential factories of natural and mimetic strategies for congenital malformations

BACKGROUND

Mesenchymal stem cells (MSCs) derived from gestational tissues offer a promising avenue for prenatal intervention in congenital malformations although their application is hampered by concerns related to cellular plasticity and the need for invasive, high-risk surgical procedures. Here, we present naturally occurring exosomes (EXOs) isolated from amniotic fluid-derived MSCs (AF-MSCs) and their mimetic analogs (MIMs) as viable, reproducible, and stable alternatives. These nanovesicles present a minimally invasive therapeutic option, addressing the limitations of MSC-based treatments while retaining therapeutic efficacy.

METHODS

MIMs were generated from AF-MSCs by combining sequential filtration steps through filter membranes with different porosity and size exclusion chromatography columns. A physicochemical, structural, and molecular comparison was conducted with exosomes (EXOs) released from the same batch of cells. Additionally, their distribution patterns in female mice were evaluated following in vivo administration, along with an assessment of their safety profile throughout gestation in a mouse strain predisposed to neural tube defects (NTDs). The possibility to exploit both formulations as mRNA-therapeutics was explored by evaluating cell uptake in two different cell types(fibroblasts, and macrophages) and mRNA functionality overtime in an in vitro experimental setting as well as in an ex vivo, whole embryo culture using pregnant C57BL6 dams.

RESULTS

Molecular and physiochemical characterization showed no differences between EXOs and MIMs, with MIMs determining a threefold greater yield. Biodistribution patterns following intraperitoneal administration were comparable between the two particle types, with the uterus being among targeted organs. No toxic effects were observed in the dams during gestation, nor were there any malformations or significant differences in the number of viable versus dead fetuses detected. MIMs delivered a more intense and prolonged expression of mRNA encoding for green fluorescent protein in macrophages and fibroblasts. An ex-vivo whole embryo culture demonstrated that MIMs mainly accumulate at the level of the yolk sac, while EXOs reach the embryo.

CONCLUSIONS

The present data confirms the potential application of EXOs and MIMs as suitable tools for prevention and treatment of NTDs and proposes MIMs as prospective vehicles to prevent congenital malformations caused by in utero exposure to drugs.

PKH Dyes Should Be Avoided in the EVs Biodistribution Study of the Brain: A Call for Caution

Introduction

Extracellular vesicles (EVs) are nanosized membrane vesicles that are naturally secreted by almost all cells and have gained considerable attention. Many studies have applied EVs to the treatment of brain diseases and validated their effectiveness. Although only a few EVs can penetrate the blood‒brain barrier (BBB) into the brain after administration, it has been proven that EVs and their cargos exert their effects by interacting with brain cells. PKH dyes are commonly used to stain EVs for distribution studies. However, systematic investigations of imaging characteristics of the PKH-labeled EVs distributed in the brain are still scarce.

Methods

We stained EVs derived from mesenchymal stem cells with PKH26 or PKH67. PKH26-labeled EVs and PKH67-labeled EVs were administered at the same time into each mouse while PKH26-labeled EVs were given through tail veins and PKH67-labeled EVs were given through intraperitoneal injection. Confocal microscopy was used to explore the distribution difference of two types of EVs given via different routes in the brain.

Results

The fluorescence of PKH26 and PKH67 had nearly identical distributions in brain slices after 1 h, 6 h, 12 h and 1 day of EV administration. Under the same confocal parameters, brain slices without EVs administration demonstrated the same result. However, liver slices from mice administered with labeled EVs showed obviously different distributions of two types PKH fluorescence.

Discussion

These findings raise questions about the ability of PKH dyes as labels for EVs when explore the EV brain distribution observed via confocal microscopy.

Extracellular vesicles in sepsis plasma mediate neuronal inflammation in the brain through miRNAs and innate immune signaling

BACKGROUND

Neuroinflammation reportedly plays a critical role in the pathogenesis of sepsis-associated encephalopathy (SAE). We previously reported that circulating plasma extracellular vesicles (EVs) from septic mice are proinflammatory. In the current study, we tested the role of sepsis plasma EVs in neuroinflammation.

METHODS

To track EVs in cells and tissues, HEK293T cell-derived EVs were labeled with the fluorescent dye PKH26. Cecal ligation and puncture (CLP) was conducted to model polymicrobial sepsis in mice. Plasma EVs were isolated by ultracentrifugation and their role in promoting neuronal inflammation was tested following intracerebroventricular (ICV) injection. miRNA inhibitors (anti-miR-146a, -122, -34a, and -145a) were applied to determine the effects of EV cargo miRNAs in the brain. A cytokine array was performed to profile microglia-released protein mediators. TLR7- or MyD88-knockout (KO) mice were utilized to determine the underlying mechanism of EVs-mediated neuroinflammation.

RESULTS

We observed the uptake of fluorescent PKH26-EVs inside the cell bodies of both microglia and neurons. Sepsis plasma EVs led to a dose-dependent cytokine release in cultured microglia, which was partially attenuated by miRNA inhibitors against the target miRNAs and in TLR7-KO cells. When administered via the ICV, sepsis plasma EVs resulted in a marked increase in the accumulation of innate immune cells, including monocyte and neutrophil and cytokine gene expression, in the brain. Although sepsis plasma EVs had no direct effect on cytokine production or neuronal injury in vitro, the conditioned media (CM) of microglia treated with sepsis plasma EVs induced neuronal cell death as evidenced by increased caspase-3 cleavage and Annexin-V staining. Cytokine arrays and bioinformatics analysis of the microglial CM revealed multiple cytokines/chemokines and other factors functionally linked to leukocyte chemotaxis and migration, TLR signaling, and neuronal death. Moreover, sepsis plasma EV-induced brain inflammation in vivo was significantly dependent on MyD88.

CONCLUSIONS

Circulating plasma EVs in septic mice cause a microglial proinflammatory response in vitro and a brain innate immune response in vivo, some of which are in part mediated by TLR7 in vitro and MyD88 signaling in vivo. These findings highlight the importance of circulating EVs in brain inflammation during sepsis.

Intra-arterial Pressure-Enabled Drug Delivery Significantly Increases Penetration of Glass Microspheres in a Porcine Liver Tumor Model

PURPOSE

To test the hypothesis that Pressure-Enabled Drug Delivery (PEDD) would improve the delivery of surrogate therapeutic glass microspheres (GMs) via hepatic artery infusion to liver tumors when compared with a conventional endhole microcatheter.

MATERIALS AND METHODS

The study was conducted in transgenic pigs (Oncopigs) with induced liver tumors. Tumors were infused intra-arterially with fluorescently labeled GM. PEDD with a specialized infusion device (TriNav; TriSalus Life Sciences, Westminster, Colorado) was compared with conventional endhole microcatheter delivery in both lobar and selective infusions. Near-infrared imaging was used to detect GM fluorescent signal in tumors. Image analysis with a custom deep learning algorithm (Visiopharm A/S) was used to quantitate signal intensity in relation to the tumor border.

RESULTS

With lobar infusions, significant increases in GM signal intensity were observed in and around tumors after PEDD (n = 10) when compared with those after conventional delivery (n = 7), with PEDD increasing penetration into the tumor by 117% (P = .004). In selective infusions, PEDD (n = 9) increased penetration into the tumor by 39% relative to conventional delivery (n = 8, P = .032). Lobar PEDD of GMs to the tumor was statistically equivalent to conventional selective delivery (P = .497).

CONCLUSIONS

PEDD with a TriNav device significantly improved GM uptake in liver tumors relative to conventional infusion in both lobar and selective procedures. Lobar GM delivery with PEDD was equivalent to conventional selective delivery with an endhole device, suggesting that proximal PEDD infusions may enable effective delivery without selection of distal target vessels.

Role of probiotic extracellular vesicles in inter-kingdom communication and current technical limitations in advancing their therapeutic utility

Diverse functions of probiotic extracellular vesicles (EVs) have been extensively studied over the past decade, proposing their role in inter-kingdom communication. Studies have explored their therapeutic role in pathophysiological processes ranging from cancer, immunoregulation, and ulcerative colitis to stress-induced depression. These studies have highlighted the significant and novel potential of probiotic EVs for therapeutic applications, offering immense promise in addressing several unmet clinical needs. Additionally, probiotic EVs are being explored as vehicles for targeted delivery approaches. However, the realization of clinical utility of probiotic EVs is hindered by several knowledge gaps, pitfalls, limitations, and challenges, which impede their wider acceptance by the scientific community. Among these, limited knowledge of EV biogenesis, markers and regulators in bacteria, variations in cargo due to culture conditions or EV isolation method, and lack of proper understanding of gut uptake and demonstration of in vivo effect are some important issues. This review aims to summarize the diverse roles of probiotic EVs in health and disease conditions. More importantly, it discusses the significant knowledge gaps and limitations that stand in the way of the therapeutic utility of probiotic EVs. Furthermore, the importance of addressing these gaps and limitations with technical advances such as rigorous omics has been discussed.

Protective effects of mesenchymal stem cells-derived extracellular vesicles against ischemia-reperfusion injury of hearts donated after circulatory death: Preliminary study in a pig model

INTRODUCTION

Insufficient supply of cardiac grafts represents a severe obstacle in heart transplantation. Donation after Circulatory Death (DCD), in addition to conventional donation after brain death, is one promising option to overcome the organ shortage. However, DCD organs undergo an inevitable more extended period of warm unprotected ischemia between circulatory arrest and graft procurement. Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) have shown remarkable protective effects against ischemia-reperfusion injury. Thus, we aimed to enhance grafts preservation from DCD donors, through treatment with MSC-EVs.

METHODS

Female pigs were euthanized by barbiturate overdose and after 20 min of a flat EKG, the chest was opened, the heart harvested and subsequently connected to an extracorporeal perfusion machine. MSC-EVs, isolated by ion exchange chromatography, were added to the perfusion solution (1×1011 particles) and the heart was perfused for 2 h. Then, heart tissue biopsies were taken to assess histological changes, mitochondrial morphology, antioxidant enzyme activity and inflammation mediators' expression. Biochemical parameters of myocardial viability were assessed in the perfusate.

RESULTS

The treatment with MSC-EVs significantly prevented mitochondria swelling, mitochondrial cristae loss and oxidative stress in cardiac tissue. The protective effect of MSC-EVs was confirmed by the delayed increase of the cardiac-specific enzymes CK and TnC in the perfusate and the reduction of caspase-3+ cells in tissue sections.

CONCLUSION

MSC-EVs improve graft quality by preserving the mitochondrial ultrastructure protecting the myocardium against oxidative stress, reducing apoptosis of cardiac cells and preventing the increase of pro-inflammatory cytokines.

Extracellular vesicles release from protozoa parasite and animal model

Diseases caused by protozoan parasites, such as leishmaniasis, trypanosomiasis, and malaria, are highly complex and together continue to cause high annual morbidity and mortality. The search for new compounds in environmental biodiversity, repositioning known drugs, and developing vaccines using old and innovative technologies have been employed to discover vaccines and new and alternative treatments. Extracellular vesicles (EVs) can carry parasite antigens, creating a new possibility to develop an effective and affordable platform for treatment, vaccines, and drug delivery. Thus, the evaluation of EVs in animal models can and should be explored among the countless biomedical applications. Herein, we will address the concept of EVs, their acquisition and characterization in protozoan parasite models, and the primary studies using these vesicles in therapeutic applications.

INDUCED PLURIPOTENT STEM CELL-DERIVED MESENCHYMAL STEM CELLS-DERIVED EXTRACELLULAR VESICLES ATTENUATE LPS-INDUCED LUNG INJURY AND ENDOTOXEMIA IN MICE

ABSTRACT

Introduction: We hypothesized extracellular vesicles (EVs) from preconditioned human-induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) attenuate LPS-induced acute lung injury (ALI) and endotoxemia. Methods: iMSCs were incubated with cell stimulation cocktail (CSC) and EVs were isolated. iMSC-EVs were characterized by size and EV markers. Biodistribution of intratracheal (IT), intravenous, and intraperitoneal injection of iMSC-EVs in mice was examined using IVIS. Uptake of iMSC-EVs in lung tissue, alveolar macrophages, and RAW264.7 cells was also assessed. C57BL/6 mice were treated with IT/IP iMSC-EVs or vehicle ± IT/IP LPS to induce ALI/acute respiratory distress syndrome and endotoxemia. Lung tissues, plasma, and bronchoalveolar lavage fluid (BALF) were harvested at 24 h. Lung histology, BALF neutrophil/macrophage, cytokine levels, and total protein concentration were measured to assess ALI and inflammation. Survival studies were performed using IP LPS in mice for 3 days. Results: iMSC-EV route of administration resulted in differential tissue distribution. iMSC-EVs were taken up by alveolar macrophages in mouse lung and cultured RAW264.7 cells. IT LPS-treated mice demonstrated marked histologic ALI, increased BALF neutrophils/macrophages and protein, and increased BALF and plasma TNF-α/IL-6 levels. These parameters were attenuated by 2 h before or 2 h after treatment with IT iMSC-EVs in ALI mice. Interestingly, the IT LPS-induced increase in IL-10 was augmented by iMSC-EVs. Mice treated with IP LPS showed increases in TNF-α and IL-6 that were downregulated by iMSC-EVs and LPS-induced mortality was ameliorated by iMSC-EVs. Administration of IT iMSC-EVs 2 h after LPS downregulated the increase in proinflammatory cytokines (TNF-α/IL-6) by LPS and further increased IL-10 levels. Conclusions: iMSC-EVs attenuate the inflammatory effects of LPS on cytokine levels in ALI and IP LPS in mice. LPS-induced mortality was improved with administration of iMSC-EVs.

Quality and Safety Considerations for Therapeutic Products Based on Extracellular Vesicles

Extracellular vesicles (EVs) serve as an intrinsic system for delivering functional molecules within our body, playing significant roles in diverse physiological phenomena and diseases. Both native and engineered EVs are currently the subject of extensive research as promising therapeutics and drug delivery systems, primarily due to their remarkable attributes, such as targeting capabilities, biocompatibility, and low immunogenicity and mutagenicity. Nevertheless, their clinical application is still a long way off owing to multiple limitations. In this context, the Science Board of the Pharmaceuticals and Medical Devices Agency (PMDA) of Japan has conducted a comprehensive assessment to identify the current issues related to the quality and safety of EV-based therapeutic products. Furthermore, we have presented several examples of the state-of-the-art methodologies employed in EV manufacturing, along with guidelines for critical processes, such as production, purification, characterization, quality evaluation and control, safety assessment, and clinical development and evaluation of EV-based therapeutics. These endeavors aim to facilitate the clinical application of EVs and pave the way for their transformative impact in healthcare.

The emerging role of extracellular vesicles in the diagnosis and treatment of autism spectrum disorders

Autism spectrum disorders (ASD) are neurodevelopmental conditions characterized by restricted, repetitive behavioral patterns and deficits in social interactions. The prevalence of ASD has continued to rise in recent years. However, the etiology and pathophysiology of ASD remain largely unknown. Currently, the diagnosis of ASD relies on behavior measures, and there is a lack of reliable and objective biomarkers. In addition, there are still no effective pharmacologic therapies for the core symptoms of ASD. Extracellular vesicles (EVs) are lipid bilayer nanovesicles secreted by almost all types of cells. EVs play a vital role in cell-cell communications and are known to bear various biological functions. Emerging evidence demonstrated that EVs are involved in many physiological and pathological processes throughout the body and the content in EVs can reflect the status of the originating cells. EVs have demonstrated the potential of broad applications for the diagnosis and treatment of various brain diseases, suggesting that EVs may have also played a role in the pathological process of ASD. Besides, EVs can be utilized as therapeutic agents for their endogenous substances and biological functions. Additionally, EVs can serve as drug delivery tools as nano-sized vesicles with inherent targeting ability. Here, we discuss the potential of EVs to be considered as promising diagnostic biomarkers and their potential therapeutic applications for ASD.

Most recent advances and applications of extracellular vesicles in tackling neurological challenges

Over the past few decades, there has been a notable increase in the global burden of central nervous system (CNS) diseases. Despite advances in technology and therapeutic options, neurological and neurodegenerative disorders persist as significant challenges in treatment and cure. Recently, there has been a remarkable surge of interest in extracellular vesicles (EVs) as pivotal mediators of intercellular communication. As carriers of molecular cargo, EVs demonstrate the ability to traverse the blood-brain barrier, enabling bidirectional communication. As a result, they have garnered attention as potential biomarkers and therapeutic agents, whether in their natural form or after being engineered for use in the CNS. This review article aims to provide a comprehensive introduction to EVs, encompassing various aspects such as their diverse isolation methods, characterization, handling, storage, and different routes for EV administration. Additionally, it underscores the recent advances in their potential applications in neurodegenerative disorder therapeutics. By exploring their unique capabilities, this study sheds light on the promising future of EVs in clinical research. It considers the inherent challenges and limitations of these emerging applications while incorporating the most recent updates in the field.

Bioengineering extracellular vesicle cargo for optimal therapeutic efficiency

Extracellular vesicles (EVs) have the innate ability to carry proteins, lipids, and nucleic acids between cells, and thus these vesicles have gained much attention as potential therapeutic delivery vehicles. Many strategies have been explored to enhance the loading of specific cargoes of interest into EVs, which could result in the delivery of more therapeutic to recipient cells, thus enhancing therapeutic efficacy. In this review, we discuss the natural biogenesis of EVs, the mechanism by which proteins and nucleic acids are selected for inclusion in EVs, and novel methods that have been employed to enhance loading of specific cargoes into EVs. As well, we discuss biodistribution of administered EVs in vivo and summarize clinical trials that have attempted to harness the therapeutic potential of EVs.

Regulation of the Nrf2/HO-1 axis by mesenchymal stem cells-derived extracellular vesicles: implications for disease treatment

This comprehensive review inspects the therapeutic potential of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) across multiple organ systems. Examining their impact on the integumentary, respiratory, cardiovascular, urinary, and skeletal systems, the study highlights the versatility of MSC-EVs in addressing diverse medical conditions. Key pathways, such as Nrf2/HO-1, consistently emerge as central mediators of their antioxidative and anti-inflammatory effects. From expediting diabetic wound healing to mitigating oxidative stress-induced skin injuries, alleviating acute lung injuries, and even offering solutions for conditions like myocardial infarction and renal ischemia-reperfusion injury, MSC-EVs demonstrate promising therapeutic efficacy. Their adaptability to different administration routes and identifying specific factors opens avenues for innovative regenerative strategies. This review positions MSC-EVs as promising candidates for future clinical applications, providing a comprehensive overview of their potential impact on regenerative medicine.

Intranasal administration of stem cell-derived exosomes for central nervous system diseases

ABSTRACT

Exosomes, lipid bilayer-enclosed small cellular vesicles, are actively secreted by various cells and play crucial roles in intercellular communication. These nanosized vesicles transport internalized proteins, mRNA, miRNA, and other bioactive molecules. Recent findings have provided compelling evidence that exosomes derived from stem cells hold great promise as a therapeutic modality for central nervous system disorders. These exosomes exhibit multifaceted properties including anti-apoptotic, anti-inflammatory, neurogenic, and vasculogenic effects. Furthermore, exosomes offer several advantages over stem cell therapy, such as high preservation capacity, low immunogenicity, the ability to traverse the blood-brain barrier, and the potential for drug encapsulation. Consequently, researchers have turned their attention to exosomes as a novel therapeutic avenue. Nonetheless, akin to the limitations of stem cell treatment, the limited accumulation of exosomes in the injured brain poses a challenge to their clinical application. To overcome this hurdle, intranasal administration has emerged as a non-invasive and efficacious route for delivering drugs to the central nervous system. By exploiting the olfactory and trigeminal nerve axons, this approach enables the direct transport of therapeutics to the brain while bypassing the blood-brain barrier. Notably, exosomes, owing to their small size, can readily access the nerve pathways using this method. As a result, intranasal administration has gained increasing recognition as an optimal therapeutic strategy for exosome-based treatments. In this comprehensive review, we aim to provide an overview of both basic and clinical research studies investigating the intranasal administration of exosomes for the treatment of central nervous system diseases. Furthermore, we elucidate the underlying therapeutic mechanisms and offer insights into the prospect of this approach.

Mesenchymal stromal cell-derived extracellular vesicles therapy openings new translational challenges in immunomodulating acute liver inflammation

Inflammation plays a critical role in conditions such as acute liver failure, acute-on-chronic liver failure, and ischemia-reperfusion-induced liver injury. Various pathogenic pathways contribute to liver inflammation, involving inflammatory polarization of macrophages and Küpffer cells, neutrophil infiltration, dysregulation of T cell subsets, oxidative stress, and activation of hepatic stellate cells. While mesenchymal stromal cells (MSCs) have demonstrated beneficial properties, their clinical translation is limited by their cellular nature. However, MSC-derived extracellular vesicles (MSC-EVs) have emerged as a promising cell-free therapeutic approach for immunomodulation. MSC-EVs naturally mirror their parental cell properties, overcoming the limitations associated with the use of MSCs. In vitro and in vivo preclinical studies have demonstrated that MSC-EVs replicate the beneficial effects of MSCs in liver injury. This includes the reduction of cell death and oxidative stress, improvement of hepatocyte function, induction of immunomodulatory effects, and mitigation of cytokine storm. Nevertheless, MSC-EVs face challenges regarding the necessity of defining consistent isolation methods, optimizing MSCs culture conditions, and establishing quality control measures for EV characterization and functional assessment. By establishing standardized protocols, guidelines, and affordable cost mass production, clinicians and researchers will have a solid foundation to conduct further studies, validate the therapeutic efficacy of MSC-EVs, and ultimately pave the way for their clinical implementation in acute liver injury.

Intranasal drug delivery: The interaction between nanoparticles and the nose-to-brain pathway

Intranasal delivery provides a direct and non-invasive method for drugs to reach the central nervous system. Nanoparticles play a crucial role as carriers in augmenting the efficacy of brain delivery. However, the interaction between nanoparticles and the nose-to-brain pathway and how the various biopharmaceutical factors affect brain delivery efficacy remains unclear. In this review, we comprehensively summarized the anatomical and physiological characteristics of the nose-to-brain pathway and the obstacles that hinder brain delivery. We then outlined the interaction between nanoparticles and this pathway and reviewed the biomedical applications of various nanoparticulate drug delivery systems for nose-to-brain drug delivery. This review aims at inspiring innovative approaches for enhancing the effectiveness of nose-to-brain drug delivery in the treatment of different brain disorders.

Extracellular Vesicles Loaded with Long Antisense RNAs Repress Severe Acute Respiratory Syndrome Coronavirus 2 Infection

Long antisense RNAs (asRNAs) have been observed to repress HIV and other virus expression in a manner that is refractory to viral evolution. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) disease, has a distinct ability to evolve resistance around antibody targeting, as was evident from the emergence of various SARS-CoV-2 spike antibody variants. Importantly, the effectiveness of current antivirals is waning due to the rapid emergence of new variants of concern, more recently the omicron variant. One means of avoiding the emergence of viral resistance is by using long asRNA to target SARS-CoV-2. Similar work has proven successful with HIV targeting by long asRNA. In this study, we describe a long asRNA targeting SARS-CoV-2 RNA-dependent RNA polymerase gene and the ability to deliver this RNA in extracellular vesicles (EVs) to repress virus expression. The observations presented in this study suggest that EV-delivered asRNAs are one means to targeting SARS-CoV-2 infection, which is both effective and broadly applicable as a means to control viral expression in the absence of mutation. This is the first demonstration of the use of engineered EVs to deliver long asRNA payloads for antiviral therapy.

Intranasal Administration of Mesenchymal Stem Cell-Derived Exosome Alleviates Hypoxic-Ischemic Brain Injury

Hypoxic-ischemic brain injury arises from inadequate oxygen delivery to the brain, commonly occurring following cardiac arrest, which lacks effective treatments. Recent studies have demonstrated the therapeutic potential of exosomes released from mesenchymal stem cells. Given the challenge of systemic dilution associated with intravenous administration, intranasal delivery has emerged as a promising approach. In this study, we investigate the effects of intranasally administered exosomes in an animal model. Exosomes were isolated from the cell supernatants using the ultracentrifugation method. Brain injury was induced in Sprague-Dawley rats through a transient four-vessel occlusion model. Intranasal administration was conducted with 3 × 108 exosome particles in 20 µL of PBS or PBS alone, administered daily for 7 days post-injury. Long-term cognitive behavioral assessments, biodistribution of exosomes, and histological evaluations of apoptosis and neuroinflammation were conducted. Exosomes were primarily detected in the olfactory bulb one hour after intranasal administration, subsequently distributing to the striatum and midbrain. Rats treated with exosomes exhibited substantial improvement in cognitive function up to 28 days after the insult, and demonstrated significantly fewer apoptotic cells along with higher neuronal cell survival in the hippocampus. Exosomes were found to be taken up by microglia, leading to a decrease in the expression of cytotoxic inflammatory markers.

Mesenchymal stromal cells and CAR-T cells in regenerative medicine: The homing procedure and their effective parameters

Mesenchymal stromal cells (MSCs) and chimeric antigen receptor (CAR)-T cells are two core elements in cell therapy procedures. MSCs have significant immunomodulatory effects that alleviate inflammation in the tissue regeneration process, while administration of specific chemokines and adhesive molecules would primarily facilitate CAR-T cell trafficking into solid tumors. Multiple parameters affect cell homing, including the recipient's age, the number of cell passages, proper cell culture, and the delivery method. In addition, several chemokines are involved in the tumor microenvironment, affecting the homing procedure. This review discusses parameters that improve the efficiency of cell homing and significant cell therapy challenges. Emerging comprehensive mechanistic strategies such as non-systemic and systemic homing that revealed a significant role in cell therapy remodeling were also reviewed. Finally, the primary implications for the development of combination therapies that incorporate both MSCs and CAR-T cells for cancer treatment were discussed.

Exosome-based delivery strategies for tumor therapy: an update on modification, loading, and clinical application

Malignancy is a major public health problem and among the leading lethal diseases worldwide. Although the current tumor treatment methods have therapeutic effect to a certain extent, they still have some shortcomings such as poor water solubility, short half-life, local and systemic toxicity. Therefore, how to deliver therapeutic agent so as to realize safe and effective anti-tumor therapy become a problem urgently to be solved in this field. As a medium of information exchange and material transport between cells, exosomes are considered to be a promising drug delivery carrier due to their nano-size, good biocompatibility, natural targeting, and easy modification. In this review, we summarize recent advances in the isolation, identification, drug loading, and modification of exosomes as drug carriers for tumor therapy alongside their application in tumor therapy. Basic knowledge of exosomes, such as their biogenesis, sources, and characterization methods, is also introduced herein. In addition, challenges related to the use of exosomes as drug delivery vehicles are discussed, along with future trends. This review provides a scientific basis for the application of exosome delivery systems in oncological therapy.

Systemic Treatment with Fas-Blocking Peptide Attenuates Apoptosis in Brain Ischemia

Apoptosis plays a crucial role in neuronal injury, with substantial evidence implicating Fas-mediated cell death as a key factor in ischemic strokes. To address this, inhibition of Fas-signaling has emerged as a promising strategy in preventing neuronal cell death and alleviating brain ischemia. However, the challenge of overcoming the blood-brain barrier (BBB) hampers the effective delivery of therapeutic drugs to the central nervous system (CNS). In this study, we employed a 30 amino acid-long leptin peptide to facilitate BBB penetration. By conjugating the leptin peptide with a Fas-blocking peptide (FBP) using polyethylene glycol (PEG), we achieved specific accumulation in the Fas-expressing infarction region of the brain following systemic administration. Notably, administration in leptin receptor-deficient db/db mice demonstrated that leptin facilitated the delivery of FBP peptide. We found that the systemic administration of leptin-PEG-FBP effectively inhibited Fas-mediated apoptosis in the ischemic region, resulting in a significant reduction of neuronal cell death, decreased infarct volumes, and accelerated recovery. Importantly, neither leptin nor PEG-FBP influenced apoptotic signaling in brain ischemia. Here, we demonstrate that the systemic delivery of leptin-PEG-FBP presents a promising and viable strategy for treating cerebral ischemic stroke. Our approach not only highlights the therapeutic potential but also emphasizes the importance of overcoming BBB challenges to advance treatments for neurological disorders.

Membrane Vesicles as Drug Delivery Systems: Source, Preparation, Modification, Drug Loading, In Vivo Administration and Biodistribution, and Application in Various Diseases

Bioinspired (or biologically inspired) drug delivery systems (DDSs) have been intensively studied in the last decades. As bioinspired DDSs, membrane vesicles, including extracellular vesicles (EVs) released from eukaryotic cells, outer membrane vesicles (OMVs) from bacteria, cell-bound membrane vesicles (CBMVs) isolated in situ from cell surfaces, membrane vesicles reorganized after the isolation of the plasma membrane of cells, and others have been rapidly developed and are attracting more and more attention. Most recently, a collection of 25 papers on the advances in membrane vesicle-based drug delivery systems was published in a Special Issue of Pharmaceutics entitled "Advances of membrane vesicles in drug delivery systems". These papers cover many related topics including the source, preparation, modification, drug loading, and in vivo administration and biodistribution of membrane vesicles (mainly extracellular vesicles or exosomes and bacterial outer membrane vesicles), as well as application of membrane vesicles as DDSs in the treatment of various diseases.