Targeting extracellular vesicles to injured tissue using membrane cloaking and surface display

Advances in preparation and engineering of plant-derived extracellular vesicles for nutrition intervention

Plant-derived extracellular vesicles (PLEVs), as a type of naturally occurring lipid bilayer membrane structure, represent an emerging delivery vehicle with immense potential due to their ability to encapsulate hydrophobic and hydrophilic compounds, shield them from external environmental stresses, control release, exhibit biocompatibility, and demonstrate biodegradability. This comprehensive review analyzes engineering preparation strategies for natural vesicles, focusing on PLEVs and their purification and surface engineering. Furthermore, it encompasses the latest advancements in utilizing PLEVs to transport active components, serving as a nanotherapeutic system. The prospects and potential development of PLEVs are also discussed. It is anticipated that this work will not only address existing knowledge gaps concerning PLEVs but also provide valuable guidance for researchers in the fields of food science and biomedical studies, stimulating novel breakthroughs in plant-based therapeutic options.

Engineering Exosomes for Therapeutic Applications: Decoding Biogenesis, Content Modification, and Cargo Loading Strategies

Exosomes emerge from endosomal invagination and range in size from 30 to 200 nm. Exosomes contain diverse proteins, lipids, and nucleic acids, which can indicate the state of various physiological and pathological processes. Studies have revealed the remarkable clinical potential of exosomes in diagnosing and prognosing multiple diseases, including cancer, cardiovascular disorders, and neurodegenerative conditions. Exosomes also have the potential to be engineered and deliver their cargo to a specific target. However, further advancements are imperative to optimize exosomes' diagnostic and therapeutic capabilities for practical implementation in clinical settings. This review highlights exosomes' diagnostic and therapeutic applications, emphasizing their engineering through simple incubation, biological, and click chemistry techniques. Additionally, the loading of therapeutic agents onto exosomes, utilizing passive and active strategies, and exploring hybrid and artificial exosomes are discussed.

Extracellular vesicle and lipoprotein diagnostics (ExoLP-Dx) with membrane sensor: A robust microfluidic platform to overcome heterogeneity

The physiological origins and functions of extracellular vesicles (EVs) and lipoproteins (LPs) propel advancements in precision medicine by offering non-invasive diagnostic and therapeutic prospects for cancers, cardiovascular, and neurodegenerative diseases. However, EV/LP diagnostics (ExoLP-Dx) face considerable challenges. Their intrinsic heterogeneity, spanning biogenesis pathways, surface protein composition, and concentration metrics complicate traditional diagnostic approaches. Commonly used methods such as nanoparticle tracking analysis, enzyme-linked immunosorbent assay, and nuclear magnetic resonance do not provide any information about their proteomic subfractions, including active proteins/enzymes involved in essential pathways/functions. Size constraints limit the efficacy of flow cytometry for small EVs and LPs, while ultracentrifugation isolation is hampered by co-elution with non-target entities. In this perspective, we propose a charge-based electrokinetic membrane sensor, with silica nanoparticle reporters providing salient features, that can overcome the interference, long incubation time, sensitivity, and normalization issues of ExoLP-Dx from raw plasma without needing sample pretreatment/isolation. A universal EV/LP standard curve is obtained despite their heterogeneities.

Engineered exosomes: a potential therapeutic strategy for septic cardiomyopathy

Septic cardiomyopathy, a life-threatening complication of sepsis, can cause acute heart failure and carry a high mortality risk. Current treatments have limitations. Fortunately, engineered exosomes, created through bioengineering technology, may represent a potential new treatment method. These exosomes can both diagnose and treat septic cardiomyopathy, playing a crucial role in its development and progression. This article examines the strategies for using engineered exosomes to protect cardiac function and treat septic cardiomyopathy. It covers three innovative aspects: exosome surface modification technology, the use of exosomes as a multifunctional drug delivery platform, and plant exosome-like nanoparticle carriers. The article highlights the ability of exosomes to deliver small molecules, proteins, and drugs, summarizing several RNA molecules, proteins, and drugs beneficial for treating septic cardiomyopathy. Although engineered exosomes are a promising biotherapeutic carrier, they face challenges in clinical application, such as understanding the interaction mechanism with host cells, distribution within the body, metabolism, and long-term safety. Further research is essential, but engineered exosomes hold promise as an effective treatment for septic cardiomyopathy.

The Discovery of Extracellular Vesicles and Their Emergence as a Next-Generation Therapy

From their humble discovery as cellular debris to cementing their natural capacity to transfer functional molecules between cells, the long-winded journey of extracellular vesicles (EVs) now stands at the precipice as a next-generation cell-free therapeutic tool to revolutionize modern-day medicine. This perspective provides a snapshot of the discovery of EVs to their emergence as a vibrant field of biology and the renaissance they usher in the field of biomedical sciences as therapeutic agents for cardiovascular pathologies. Rapid development of bioengineered EVs is providing innovative opportunities to overcome biological challenges of natural EVs such as potency, cargo loading and enhanced secretion, targeting and circulation half-life, localized and sustained delivery strategies, approaches to enhance systemic circulation, uptake and lysosomal escape, and logistical hurdles encompassing scalability, cost, and time. A multidisciplinary collaboration beyond the field of biology now extends to chemistry, physics, biomaterials, and nanotechnology, allowing rapid development of designer therapeutic EVs that are now entering late-stage human clinical trials.

Meta-analysis study of small extracellular vesicle nursing application therapies for healing of wounds and skin regeneration

We designed and performed this meta-analysis to investigate the impact of the application of extracellular small vesicle therapies on regeneration of skin and wound healing. The findings of this study were computed using fixed or random effect models. The mean differences (MDs), and odds ratio (ORs) with their 95% confidence intervals (CIs) were calculated. In this study, 43 publications were included, encompassing 530 animals with artificial wounds. Small extracellular vesicle therapy had a significant greater rate of wound closure (MD, 24.0; 95% CI, 19.98-28.02, P < 0.001), lower scar width (MD, -191.33; 95%CI, -292.26--90.4, P < 0.001), and higher blood vessel density (MD,36.11; 95%CI, 19.02-53.20, P < 0.001) compared to placebo. Our data revealed that small extracellular vesicle therapy had a significantly higher regeneration of skin and healing of wounds based on the results of wound closure rate, lower scar width, and higher blood vessel density compared to placebo. Future studies with larger sample size are needed.

Evolving Strategies for Extracellular Vesicles as Future Cardiac Therapeutics: From Macro- to Nano-Applications

Cardiovascular disease represents the foremost cause of mortality and morbidity worldwide, with a steadily increasing incidence due to the growth of the ageing population. Cardiac dysfunction leading to heart failure may arise from acute myocardial infarction (MI) as well as inflammatory- and cancer-related chronic cardiomyopathy. Despite pharmacological progress, effective cardiac repair represents an unmet clinical need, with heart transplantation being the only option for end-stage heart failure. The functional profiling of the biological activity of extracellular vesicles (EVs) has recently attracted increasing interest in the field of translational research for cardiac regenerative medicine. The cardioprotective and cardioactive potential of human progenitor stem/cell-derived EVs has been reported in several preclinical studies, and EVs have been suggested as promising paracrine therapy candidates for future clinical translation. Nevertheless, some compelling aspects must be properly addressed, including optimizing delivery strategies to meet patient needs and enhancing targeting specificity to the cardiac tissue. Therefore, in this review, we will discuss the most relevant aspects of the therapeutic potential of EVs released by human progenitors for cardiovascular disease, with a specific focus on the strategies that have been recently implemented to improve myocardial targeting and administration routes.

In vivo phage display identifies novel peptides for cardiac targeting

Heart failure remains a leading cause of mortality. Therapeutic intervention for heart failure would benefit from targeted delivery to the damaged heart tissue. Here, we applied in vivo peptide phage display coupled with high-throughput Next-Generation Sequencing (NGS) and identified peptides specifically targeting damaged cardiac tissue. We established a bioinformatics pipeline for the identification of cardiac targeting peptides. Hit peptides demonstrated preferential uptake by human induced pluripotent stem cell (iPSC)-derived cardiomyocytes and immortalized mouse HL1 cardiomyocytes, without substantial uptake in human liver HepG2 cells. These novel peptides hold promise for use in targeted drug delivery and regenerative strategies and open new avenues in cardiovascular research and clinical practice.

Navigating the landscape of RNA delivery systems in cardiovascular disease therapeutics

Cardiovascular diseases (CVDs) stand as the leading cause of death worldwide, posing a significant global health challenge. Consequently, the development of innovative therapeutic strategies to enhance CVDs treatment is imperative. RNA-based therapies, encompassing non-coding RNAs, mRNA, aptamers, and CRISPR/Cas9 technology, have emerged as promising tools for addressing CVDs. However, inherent challenges associated with RNA, such as poor cellular uptake, susceptibility to RNase degradation, and capture by the reticuloendothelial system, underscore the necessity of combining these therapies with effective drug delivery systems. Various non-viral delivery systems, including extracellular vesicles, lipid-based carriers, polymeric and inorganic nanoparticles, as well as hydrogels, have shown promise in enhancing the efficacy of RNA therapeutics. In this review, we offer an overview of the most relevant RNA-based therapeutic strategies explored for addressing CVDs and emphasize the pivotal role of delivery systems in augmenting their effectiveness. Additionally, we discuss the current status of these therapies and the challenges that hinder their clinical translation.

Recent advances in therapeutic engineered extracellular vesicles

Extracellular vesicles (EVs) are natural particles secreted by living cells, which hold significant potential for various therapeutic applications. Native EVs have specific components and structures, allowing them to cross biological barriers, and circulate in vivo for a long time. Native EVs have also been bioengineered to enhance their therapeutic efficacy and targeting affinity. Recently, the therapeutic potential of surface-engineered EVs has been explored in the treatment of tumors, autoimmune diseases, infections and other diseases by ongoing research and clinical trials. In this review, we will introduce the modified methods of engineered EVs, summarize the application of engineered EVs in preclinical and clinical trials, and discuss the opportunities and challenges for the clinical translation of surface-engineered EVs.

Approaches to Characterize and Quantify Extracellular Vesicle Surface Conjugation Efficiency

Extracellular vesicles (EVs) are cell-secreted nanovesicles that play an important role in long-range cell-cell communication. Although EVs pose a promising alternative to cell-based therapy, targeted in vivo delivery still falls short. Many studies have explored the surface modification of EVs to enhance their targeting capabilities. However, to our knowledge, there are no standardized practices to confirm the successful surface modification of EVs or calculate the degree of conjugation on EV surfaces (conjugation efficiency). These pieces of information are essential in the reproducibility of targeted EV therapeutics and the determination of optimized conjugation conditions for EVs to see significant therapeutic effects in vitro and in vivo. This review will discuss the vast array of techniques adopted, technologies developed, and efficiency definitions made by studies that have calculated EV/nanoparticle surface conjugation efficiency and how differences between studies may contribute to differently reported conjugation efficiencies.

Exploring Cutting-Edge Approaches to Potentiate Mesenchymal Stem Cell and Exosome Therapy for Myocardial Infarction

Cardiovascular diseases (CVDs) continue to be a significant global health concern. Many studies have reported promising outcomes from using MSCs and their secreted exosomes in managing various cardiovascular-related diseases like myocardial infarction (MI). MSCs and exosomes have demonstrated considerable potential in promoting regeneration and neovascularization, as well as exerting beneficial effects against apoptosis, remodeling, and inflammation in cases of myocardial infarction. Nonetheless, ensuring the durability and effectiveness of MSCs and exosomes following in vivo transplantation remains a significant concern. Recently, novel methods have emerged to improve their effectiveness and robustness, such as employing preconditioning statuses, modifying MSC and their exosomes, targeted drug delivery with exosomes, biomaterials, and combination therapy. Herein, we summarize the novel approaches that intensify the therapeutic application of MSC and their derived exosomes in treating MI.

Targeted drug delivery of engineered mesenchymal stem/stromal-cell-derived exosomes in cardiovascular disease: recent trends and future perspectives

In recent years, stem cells and their secretomes, notably exosomes, have received considerable attention in biomedical applications. Exosomes are cellular secretomes used for intercellular communication. They perform the function of intercellular messengers by facilitating the transport of proteins, lipids, nucleic acids, and therapeutic substances. Their biocompatibility, minimal immunogenicity, targetability, stability, and engineerable characteristics have additionally led to their application as drug delivery vehicles. The therapeutic efficacy of exosomes can be improved through surface modification employing functional molecules, including aptamers, antibodies, and peptides. Given their potential as targeted delivery vehicles to enhance the efficiency of treatment while minimizing adverse effects, exosomes exhibit considerable promise. Stem cells are considered advantageous sources of exosomes due to their distinctive characteristics, including regenerative and self-renewal capabilities, which make them well-suited for transplantation into injured tissues, hence promoting tissue regeneration. However, there are notable obstacles that need to be addressed, including immune rejection and ethical problems. Exosomes produced from stem cells have been thoroughly studied as a cell-free strategy that avoids many of the difficulties involved with cell-based therapy for tissue regeneration and cancer treatment. This review provides an in-depth summary and analysis of the existing knowledge regarding exosomes, including their engineering and cardiovascular disease (CVD) treatment applications.

Targeting Senescent Alveolar Epithelial Cells Using Engineered Mesenchymal Stem Cell-Derived Extracellular Vesicles To Treat Pulmonary Fibrosis

Type 2 alveolar epithelial cell (AEC2) senescence is crucial to the pathogenesis of pulmonary fibrosis (PF). The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme cluster of differentiation 38 (CD38) is a marker of senescent cells and is highly expressed in AEC2s of patients with PF, thus rendering it a potential treatment target. Umbilical cord mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) have emerged as a cell-free treatment with clinical application prospects in antiaging and antifibrosis treatments. Herein, we constructed CD38 antigen receptor membrane-modified MSC-EVs (CD38-ARM-MSC-EVs) by transfecting MSCs with a lentivirus loaded with a CD38 antigen receptor-CD8 transmembrane fragment fusion plasmid to target AEC2s and alleviate PF. Compared with MSC-EVs, the CD38-ARM-MSC-EVs engineered in this study showed a higher expression of the CD38 antigen receptor and antifibrotic miRNAs and targeted senescent AEC2s cells highly expressing CD38 in vitro and in naturally aged mouse models after intraperitoneal administration. CD38-ARM-MSC-EVs effectively restored the NAD+ levels, reversed the epithelial-mesenchymal transition phenotype, and rejuvenated senescent A549 cells in vitro, thereby mitigating multiple age-associated phenotypes and alleviating PF in aged mice. Thus, this study provides a technology to engineer MSC-EVs and support our CD38-ARM-MSC-EVs to be developed as promising agents with high clinical potential against PF.

Extracellular vesicles derived from mesenchymal stem cells: the wine in Hebe's hands to treat skin aging

Owing to its constant exposure to the external environment and various stimuli, skin ranks among the organs most vulnerable to manifestations of aging. Preventing and delaying skin aging has become one of the prominent research subjects in recent years. Mesenchymal stem cells (MSCs) are multipotent stem cells derived from mesoderm with high self-renewal ability and multilineage differentiation potential. MSC-derived extracellular vesicles (MSC-EVs) are nanoscale biological vesicles that facilitate intercellular communication and regulate biological behavior. Recent studies have shown that MSC-EVs have potential applications in anti-aging therapy due to their anti-inflammatory, anti-oxidative stress, and wound healing promoting abilities. This review presents the latest progress of MSC-EVs in delaying skin aging. It mainly includes the MSC-EVs promoting the proliferation and migration of keratinocytes and fibroblasts, reducing the expression of matrix metalloproteinases, resisting oxidative stress, and regulating inflammation. We then briefly discuss the recently discovered treatment methods of MSC-EVs in the field of skin anti-aging. Moreover, the advantages and limitations of EV-based treatments are also presented.

A novel exosome based therapeutic intervention against neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is a highly lethal variant of castration-resistant prostate cancer (CRPC) with poor survival rates. Current treatment options for NEPC are limited to highly toxic platinum drugs highlighting the urgent need for new therapies. This study aimed to develop a novel therapeutic approach using engineered exosomes against NEPC. Exosomes were modified to target CEACAM5, an NEPC surface antigen, by attaching CEACAM5 antibodies to HEK293T exosomes. These exosomes were loaded with drugs inhibiting EZH2 and the androgen receptor (AR) as recent research shows a persistent role of AR in NEPC wherein it plays a concerted role with EZH2 in driving neuronal gene programs. In vitro experiments with NEPC cell lines demonstrated that CEACAM5-targeted exosomes were specifically taken up by NEPC cells, leading to reduced cellular viability and decreased expression of neuronal markers. Further in vivo tests using a NEPC patient-derived xenograft model (LuCaP145.1) showed significant tumor regression in mice treated with engineered exosomes compared to control mice receiving IgG-labeled exosomes. These results suggest that CEACAM5-engineered exosomes hold promise as a targeted therapy for NEPC. Importantly, our exosome engineering strategy is versatile and can be adapted to target various surface antigens in prostate cancer and other diseases.

Closer to The Heart: Harnessing the Power of Targeted Extracellular Vesicle Therapies

Extracellular vesicles (EVs) have emerged as novel diagnostic and therapeutic approaches for cardiovascular diseases. EVs derived from various origins exhibit distinct effects on the cardiovascular system. However, the application of native EVs is constrained due to their poor stabilities and limited targeting capabilities. Currently, targeted modification of EVs primarily involves genetic engineering, chemical modification (covalent, non-covalent), cell membrane modification, and biomaterial encapsulation. These techniques enhance the stability, biological activity, target-binding capacity, and controlled release of EVs at specific cells and tissues. The diverse origins of cardioprotective EVs are covered, and the applications of cardiac-targeting EV delivery systems in protecting against cardiovascular diseases are discussed. This review summarizes the current stage of research on the potential of EV-based targeted therapies for addressing cardiovascular disorders.

Advances in the Generation of Constructed Cardiac Tissue Derived from Induced Pluripotent Stem Cells for Disease Modeling and Therapeutic Discovery

The human heart lacks significant regenerative capacity; thus, the solution to heart failure (HF) remains organ donation, requiring surgery and immunosuppression. The demand for constructed cardiac tissues (CCTs) to model and treat disease continues to grow. Recent advances in induced pluripotent stem cell (iPSC) manipulation, CRISPR gene editing, and 3D tissue culture have enabled a boom in iPSC-derived CCTs (iPSC-CCTs) with diverse cell types and architecture. Compared with 2D-cultured cells, iPSC-CCTs better recapitulate heart biology, demonstrating the potential to advance organ modeling, drug discovery, and regenerative medicine, though iPSC-CCTs could benefit from better methods to faithfully mimic heart physiology and electrophysiology. Here, we summarize advances in iPSC-CCTs and future developments in the vascularization, immunization, and maturation of iPSC-CCTs for study and therapy.

Mechanisms and therapeutic strategies of extracellular vesicles in cardiovascular diseases

Cardiovascular disease (CVD) significantly impacts global society since it is the leading cause of death and disability worldwide, and extracellular vesicle (EV)-based therapies have been extensively investigated. EV delivery is involved in mediating the progression of CVDs and has great potential to be biomarker and therapeutic molecular carrier. Besides, EVs from stem cells and cardiac cells can effectively protect the heart from various pathologic conditions, and then serve as an alternative treatment for CVDs. Moreover, the research of using EVs as delivery carriers of therapeutic molecules, membrane engineering modification of EVs, or combining EVs with biomaterials further improves the application potential of EVs in clinical treatment. However, currently there are only a few articles summarizing the application of EVs in CVDs. This review provides an overview of the role of EVs in the pathogenesis and diagnosis of CVDs. It also focuses on how EVs promote the repair of myocardial injury and therapeutic methods of CVDs. In conclusion, it is of great significance to review the research on the application of EVs in the treatment of CVDs, which lays a foundation for further exploration of the role of EVs, and clarifies the prospect of EVs in the treatment of myocardial injury.

Role of exosomal ncRNAs in traumatic brain injury

Traumatic brain injury (TBI) is a complex neurological disorder that often results in long-term disabilities, cognitive impairments, and emotional disturbances. Despite significant advancements in understanding the pathophysiology of TBI, effective treatments remain limited. In recent years, exosomal non-coding RNAs (ncRNAs) have emerged as potential players in TBI pathogenesis and as novel diagnostic and therapeutic targets. Exosomal ncRNAs are small RNA molecules that are secreted by cells and transported to distant sites, where they can modulate gene expression and cell signaling pathways. They have been shown to play important roles in various aspects of TBI, such as neuroinflammation, blood-brain barrier dysfunction, and neuronal apoptosis. The ability of exosomal ncRNAs to cross the blood-brain barrier and reach the brain parenchyma makes them attractive candidates for non-invasive biomarkers and drug delivery systems. However, significant challenges still need to be addressed before exosomal ncRNAs can be translated into clinical practice, including standardization of isolation and quantification methods, validation of their diagnostic and prognostic value, and optimization of their therapeutic efficacy and safety. This review aims to summarize the current knowledge regarding the role of exosomal ncRNAs in TBI, including their biogenesis, function, and potential applications in diagnosis, prognosis, and treatment. We also discuss the challenges and future perspectives of using exosomal ncRNAs as clinical tools for TBI management.

Post-insertion technique to introduce targeting moieties in milk exosomes for targeted drug delivery

BACKGROUND

Recently, increased attention has been given on exosomes as ideal nanocarriers of drugs owing to their intrinsic properties that facilitate the transport of biomolecular cargos. However, large-scale exosome production remains a major challenge in the clinical application of exosome-based drug delivery systems. Considering its biocompatibility and stability, bovine milk is a suitable natural source for large-scale and stable exosome production. Because the active-targeting ability of drug carriers is essential to maximize therapeutic efficacy and minimize side effects, precise membrane functionalization strategies are required to enable tissue-specific delivery of milk exosomes with difficulty in post-isolation modification.

METHODS

In this study, the membrane functionalization of a milk exosome platform modified using a simple post-insertion method was examined comprehensively. Exosomes were engineered from bovine milk (mExo) with surface-tunable modifications for the delivery of tumor-targeting doxorubicin (Dox). The surface modification of mExo was achieved through the hydrophobic insertion of folate (FA)-conjugated lipids.

RESULTS

We have confirmed the stable integration of functionalized PE-lipid chains into the mExo membrane through an optimized post-insertion technique, thereby effectively enhancing the surface functionality of mExo. Indeed, the results revealed that FA-modified mExo (mExo-FA) improved cellular uptake in cancer cells via FA receptor (FR)-mediated endocytosis. The designed mExo-FA selectively delivered Dox to FR-positive tumor cells and triggered notable tumor cell death, as confirmed by in vitro and in vivo analyses.

CONCLUSIONS

This simple and easy method for post-isolation modification of the exosomal surface may be used to develop milk-exosome-based drug delivery systems.

Research Advances of Engineered Exosomes as Drug Delivery Carrier

Exosomes are nanoscale vesicles secreted by living cells that have similar membrane composition to parental cells and carry a variety of proteins, lipids, and nucleic acids. Therefore, exosomes have certain biological activities and play an important role in intercellular communication. On the basis of its potential as a carrier for drug delivery systems, exosomes have been engineered to compensate for the shortage of natural exosomes through various engineering strategies for improving drug delivery efficiency, enhancing targeting to tissues and organs, and extending the circulating half-life of exosomes. This review focuses on the engineered exosomes loading drugs through different strategies, discussions on exosome surface modification strategies, and summarizes the advantages and disadvantages of different strategies. In addition, this review provides an overview of the recent applications of engineered exosomes in a number of refractory and relapsable diseases. This review has the potential to provide a reference for further research and development of engineered exosomes.

Advancements in engineered exosomes for wound repair: current research and future perspectives

Wound healing is a complex and prolonged process that remains a significant challenge in clinical practice. Exosomes, a type of nanoscale extracellular vesicles naturally secreted by cells, are endowed with numerous advantageous attributes, including superior biocompatibility, minimal toxicity, and non-specific immunogenicity. These properties render them an exceptionally promising candidate for bioengineering applications. Recent advances have illustrated the potential of exosome therapy in promoting tissue repair. To further augment their therapeutic efficacy, the concept of engineered exosomes has been proposed. These are designed and functionally modifiable exosomes that have been tailored on the attributes of natural exosomes. This comprehensive review delineates various strategies for exosome engineering, placing specific emphasis on studies exploring the application of engineered exosomes for precision therapy in wound healing. Furthermore, this review sheds light on strategies for integrating exosomes with biomaterials to enhance delivery effectiveness. The insights presented herein provide novel perspectives and lay a robust foundation for forthcoming research in the realm of cutaneous wound repair therapies.

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

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

Prospective applications of extracellular vesicle-based therapies in regenerative medicine: implications for the use of dental stem cell-derived extracellular vesicles

In the 21st century, research on extracellular vesicles (EVs) has made remarkable advancements. Recently, researchers have uncovered the exceptional biological features of EVs, highlighting their prospective use as therapeutic targets, biomarkers, innovative drug delivery systems, and standalone therapeutic agents. Currently, mesenchymal stem cells stand out as the most potent source of EVs for clinical applications in tissue engineering and regenerative medicine. Owing to their accessibility and capability of undergoing numerous differentiation inductions, dental stem cell-derived EVs (DSC-EVs) offer distinct advantages in the field of tissue regeneration. Nonetheless, it is essential to note that unmodified EVs are currently unsuitable for use in the majority of clinical therapeutic scenarios. Considering the high feasibility of engineering EVs, it is imperative to modify these EVs to facilitate the swift translation of theoretical knowledge into clinical practice. The review succinctly presents the known biotherapeutic effects of odontogenic EVs and the underlying mechanisms. Subsequently, the current state of functional cargo loading for engineered EVs is critically discussed. For enhancing EV targeting and in vivo circulation time, the review highlights cutting-edge engineering solutions that may help overcome key obstacles in the clinical application of EV therapeutics. By presenting innovative concepts and strategies, this review aims to pave the way for the adaptation of DSC-EVs in regenerative medicine within clinical settings.

Engineered Extracellular Vesicles: Emerging Therapeutic Strategies for Translational Applications

Extracellular vesicles (EVs) are small, membrane-bound vesicles used by cells to deliver biological cargo such as proteins, mRNA, and other biomolecules from one cell to another, thus inducing a specific response in the target cell and are a powerful method of cell to cell and organ to organ communication, especially during the pathogenesis of human disease. Thus, EVs may be utilized as prognostic and diagnostic biomarkers, but they also hold therapeutic potential just as mesenchymal stem cells have been used in therapeutics. However, unmodified EVs exhibit poor targeting efficacy, leading to the necessity of engineered EVS. To highlight the advantages and therapeutic promises of engineered EVs, in this review, we summarized the research progress on engineered EVs in the past ten years, especially in the past five years, and highlighted their potential applications in therapeutic development for human diseases. Compared to the existing stem cell-derived EV-based therapeutic strategies, engineered EVs show greater promise in clinical applications: First, engineered EVs mediate good targeting efficacy by exhibiting a targeting peptide that allows them to specifically target a specific organ or even cell type, thus avoiding accumulation in undesired locations and increasing the potency of the treatment. Second, engineered EVs can be artificially pre-loaded with any necessary biomolecular cargo or even therapeutic drugs to treat a variety of human diseases such as cancers, neurological diseases, and cardiovascular ailments. Further research is necessary to improve logistical challenges in large-scale engineered EV manufacturing, but current developments in engineered EVs prove promising to greatly improve therapeutic treatment for traditionally difficult to treat diseases.

New insights in application of mesenchymal stem cells therapy in tumor microenvironment: pros and cons

Multipotent mesenchymal stem cells (MSCs) are widely accepted as a useful tool for cell-based therapy of various diseases including malignancies. The therapeutic effects of MSCs are mainly attributed to their immunomodulatory and immunosuppressive properties. Despite the promising outcomes of MSCs in cancer therapy, a growing body of evidence implies that MSCs also show tumorigenic properties in the tumor microenvironment (TME), which might lead to tumor induction and progression. Owing to the broad-spectrum applications of MSCs, this challenge needs to be tackled so that they can be safely utilized in clinical practice. Herein, we review the diverse activities of MSCs in TME and highlight the potential methods to convert their protumorigenic characteristics into onco-suppressive effects.

Studying exogenous extracellular vesicle biodistribution by in vivo fluorescence microscopy

Extracellular vesicles (EVs) are lipid-bound vesicles released from cells that play a crucial role in many physiological processes and pathological mechanisms. As such, there is great interest in their biodistribution. One currently accessible technology to study their fate in vivo involves fluorescent labelling of exogenous EVs followed by whole-animal imaging. Although this is not a new technology, its translation from studying the fate of whole cells to subcellular EVs requires adaptation of the labelling techniques, excess dye removal and a refined experimental design. In this Review, we detail the methods and considerations for using fluorescence in vivo and ex vivo imaging to study the biodistribution of exogenous EVs and their roles in physiology and disease biology.

Imaging platforms to dissect the in vivo communication, biodistribution and controlled release of extracellular vesicles

Extracellular vesicles (EVs) work as communication vehicles, allowing the exchange of bioactive molecules (microRNAs, mRNAs, proteins, etc) between neighbouring and distant cells in the organism. EVs are thus important players in several physiological and pathological processes. Thus, it is critical to understand their role in cellular/organ communication to fully evaluate their biological, diagnosis and therapeutic potential. In addition, recent studies have explored the controlled release of EVs for regenerative medicine applications and thus the evaluation of their release profile is important to correlate with biological activity. Here, we give a brief introduction about EV imaging platforms in terms of their sensitivity, penetration depth, cost, and operational simplicity, followed by a discussion of different EV labelling processes with their advantages and limitations. Next, we cover the relevance of these imaging platforms to dissect the tropism and biological role of endogenous EVs. We also cover the relevance of imaging platforms to monitor the accumulation of exogenous EVs and their potential cellular targets. Finally, we highlight the importance of imaging platforms to investigate the release profile of EVs from different controlled systems.

Milk Exosomes: Next-Generation Agents for Delivery of Anticancer Drugs and Therapeutic Nucleic Acids

Exosomes are nanovesicles 40-120 nm in diameter secreted by almost all cell types and providing humoral intercellular interactions. Given the natural origin and high biocompatibility, the potential for loading various anticancer molecules and therapeutic nucleic acids inside, and the surface modification possibility for targeted delivery, exosomes are considered to be a promising means of delivery to cell cultures and experimental animal organisms. Milk is a unique natural source of exosomes available in semi-preparative and preparative quantities. Milk exosomes are highly resistant to the harsh conditions of the gastrointestinal tract. In vitro studies have demonstrated that milk exosomes have an affinity to epithelial cells, are digested by cells by endocytosis mechanism, and can be used for oral delivery. With milk exosome membranes containing hydrophilic and hydrophobic components, exosomes can be loaded with hydrophilic and lipophilic drugs. This review covers a number of scalable protocols for isolating and purifying exosomes from human, cow, and horse milk. Additionally, it considers passive and active methods for drug loading into exosomes, as well as methods for modifying and functionalizing the surface of milk exosomes with specific molecules for more efficient and specific delivery to target cells. In addition, the review considers various approaches to visualize exosomes and determine cellular localization and bio-distribution of loaded drug molecules in tissues. In conclusion, we outline new challenges for studying milk exosomes, a new generation of targeted delivery agents.

Surface-Engineered Extracellular Vesicles in Cancer Immunotherapy

Extracellular vesicles (EVs) are lipid bilayer-enclosed bodies secreted by all cell types. EVs carry bioactive materials, such as proteins, lipids, metabolites, and nucleic acids, to communicate and elicit functional alterations and phenotypic changes in the counterpart stromal cells. In cancer, cells secrete EVs to shape a tumor-promoting niche. Tumor-secreted EVs mediate communications with immune cells that determine the fate of anti-tumor therapeutic effectiveness. Surface engineering of EVs has emerged as a promising tool for the modulation of tumor microenvironments for cancer immunotherapy. Modification of EVs' surface with various molecules, such as antibodies, peptides, and proteins, can enhance their targeting specificity, immunogenicity, biodistribution, and pharmacokinetics. The diverse approaches sought for engineering EV surfaces can be categorized as physical, chemical, and genetic engineering strategies. The choice of method depends on the specific application and desired outcome. Each has its advantages and disadvantages. This review lends a bird's-eye view of the recent progress in these approaches with respect to their rational implications in the immunomodulation of tumor microenvironments (TME) from pro-tumorigenic to anti-tumorigenic ones. The strategies for modulating TME using targeted EVs, their advantages, current limitations, and future directions are discussed.

The human neurosecretome: extracellular vesicles and particles (EVPs) of the brain for intercellular communication, therapy, and liquid-biopsy applications

Emerging evidence suggests that brain derived extracellular vesicles (EVs) and particles (EPs) can cross blood-brain barrier and mediate communication among neurons, astrocytes, microglial, and other cells of the central nervous system (CNS). Yet, a complete understanding of the molecular landscape and function of circulating EVs & EPs (EVPs) remain a major gap in knowledge. This is mainly due to the lack of technologies to isolate and separate all EVPs of heterogeneous dimensions and low buoyant density. In this review, we aim to provide a comprehensive understanding of the neurosecretome, including the extracellular vesicles that carry the molecular signature of the brain in both its microenvironment and the systemic circulation. We discuss the biogenesis of EVPs, their function, cell-to-cell communication, past and emerging isolation technologies, therapeutics, and liquid-biopsy applications. It is important to highlight that the landscape of EVPs is in a constant state of evolution; hence, we not only discuss the past literature and current landscape of the EVPs, but we also speculate as to how novel EVPs may contribute to the etiology of addiction, depression, psychiatric, neurodegenerative diseases, and aid in the real time monitoring of the "living brain". Overall, the neurosecretome is a concept we introduce here to embody the compendium of circulating particles of the brain for their function and disease pathogenesis. Finally, for the purpose of inclusion of all extracellular particles, we have used the term EVPs as defined by the International Society of Extracellular Vesicles (ISEV).

Signal amplification strategies in biosensing of extracellular vesicles (EVs)

Extracellular vesicles (EVs) are membrane-enclosed vesicles secreted from mammalian cells. EVs act as multicomponent delivery vehicles to carry a wide variety of biological molecular information and participate in intercellular communications. Since elevated levels of EVs are associated with some pathological states such as inflammatory diseases and cancers, probing circulating EVs holds a great potential for early diagnostics. To this end, several detection methods have been developed in which biosensors have attracted great attentions in identification of EVs due to their simple instrumentation, versatile design and portability for point-of-care applications. The concentrations of EVs in bodily fluids are extremely low (i.e. 1-100 per μl) at early stages of a disease, which necessitates the use of signal amplification strategies for EVs detection. In this way, this review presents and discusses various amplification strategies for EVs biosensors based on detection modalities including surface plasmon resonance (SPR), calorimetry, fluorescence, electrochemical and electrochemiluminescence (ECL). In addition, microfluidic systems employed for signal amplification are reviewed and discussed in terms of their design and integration with the detection methods.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: Hype or Hope for Skeletal Muscle Anti-Frailty

Steadily rising population ageing is a global demographic trend due to the advancement of new treatments and technologies in the medical field. This trend also indicates an increasing prevalence of age-associated diseases, such as loss of muscle mass (sarcopenia), which tends to afflict the older population. The deterioration in muscle function can cause severe disability and seriously affects a patient's quality of life. Currently, there is no treatment to prevent and reverse age-related skeletal muscle ageing frailty. Existing interventions mainly slow down and control the signs and symptoms. Mesenchymal stem cell-derived extracellular vesicle (MSC-EV) therapy is a promising approach to attenuate age-related skeletal muscle ageing frailty. However, more studies, especially large-scale randomised clinical trials need to be done in order to determine the adequacy of MSC-EV therapy in treating age-related skeletal muscle ageing frailty. This review compiles the present knowledge of the causes and changes regarding skeletal muscle ageing frailty and the potential of MSC-EV transplantation as a regenerative therapy for age-related skeletal muscle ageing frailty and its clinical trials.

Engineered Extracellular Vesicles as a Targeted Delivery Platform for Precision Therapy

Extracellular vesicles (EVs)-based cell-free strategy has shown therapeutic potential in tissue regeneration. Due to their important roles in intercellular communications and their natural ability to shield cargos from degradation, EVs are also emerged as novel delivery vehicles for various bioactive molecules and drugs. Accumulating studies have revealed that EVs can be modified to enhance their efficacy and specificity for the treatment of many diseases. Engineered EVs are poised as the next generation of targeted delivery platform in the field of precision therapy. In this review, the unique properties of EVs are overviewed in terms of their biogenesis, contents, surface features and biological functions, and the recent advances in the strategies of engineered EVs construction are summarized. Additionally, we also discuss the potential applications of engineered EVs in targeted therapy of cancer and damaged tissues, and evaluate the opportunities and challenges for translating them into clinical practice.

Exosomes; multifaceted nanoplatform for targeting brain cancers

At the moment, anaplastic changes within the brain are challenging due to the complexity of neural tissue, leading to the inefficiency of therapeutic protocols. The existence of a cellular interface, namely the blood-brain barrier (BBB), restricts the entry of several macromolecules and therapeutic agents into the brain. To date, several nano-based platforms have been used in laboratory settings and in vivo conditions to overcome the barrier properties of BBB. Exosomes (Exos) are one-of-a-kind of extracellular vesicles with specific cargo to modulate cell bioactivities in a paracrine manner. Regarding unique physicochemical properties and easy access to various biofluids, Exos provide a favorable platform for drug delivery and therapeutic purposes. Emerging data have indicated that Exos enable brain penetration of selective cargos such as bioactive factors and chemotherapeutic compounds. Along with these statements, the application of smart delivery approaches can increase delivery efficiency and thus therapeutic outcomes. Here, we highlighted the recent advances in the application of Exos in the context of brain tumors.

Cardiac tissue engineering for myocardial infarction treatment

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

The biodistribution of placental and fetal extracellular vesicles during pregnancy following placentation

Human pregnancy is a highly orchestrated process requiring extensive cross-talk between the mother and the fetus. Extracellular vesicles released by the fetal tissue, particularly the placenta, are recognized as important mediators of this process. More recently, the importance of placental extracellular vesicle biodistribution studies in animal models has received increasing attention as identifying the organs to which extracellular vesicles are targeted to helps us understand more about this communication system. Placental extracellular vesicles are categorized based on their size into macro-, large-, and small-extracellular vesicles, and their biodistribution is dependent on the extracellular vesicle's particle size, the direction of blood flow, the recirculation of blood, as well as the retention capacity in organs. Macro-extracellular vesicles are exclusively localized to the lungs, while large- and small-extracellular vesicles show high levels of distribution to the lungs and liver, while there is inconsistency in the reporting of distribution to the spleen and kidneys. This inconsistency may be due to the differences in the methodologies employed between studies and their limitations. Future studies should incorporate analysis of placental extracellular vesicle biodistribution at the macroscopic level on whole animals and organs/tissues, as well as the microscopic cellular level.

Cancer nanomedicine: a review of nano-therapeutics and challenges ahead

Cancer is known as the most dangerous disease in the world in terms of mortality and lack of effective treatment. Research on cancer treatment is still active and of great social importance. Since 1930, chemotherapeutics have been used to treat cancer. However, such conventional treatments are associated with pain, side effects, and a lack of targeting. Nanomedicines are an emerging alternative due to their targeting, bioavailability, and low toxicity. Nanoparticles target cancer cells via active and passive mechanisms. Since FDA approval for Doxil®, several nano-therapeutics have been developed, and a few have received approval for use in cancer treatment. Along with liposomes, solid lipid nanoparticles, polymeric nanoparticles, and nanoemulsions, even newer techniques involving extracellular vesicles (EVs) and thermal nanomaterials are now being researched and implemented in practice. This review highlights the evolution and current status of cancer therapy, with a focus on clinical/pre-clinical nanomedicine cancer studies. Insight is also provided into the prospects in this regard.

Endogenous Lipid Carriers—Bench-to-Bedside Roadblocks in Production and Drug Loading of Exosomes

Exosomes are cell-derived, nano-sized extracellular vesicles comprising a lipid bilayer membrane that encapsulates several biological components, such as nucleic acids, lipids, and proteins. The role of exosomes in cell–cell communication and cargo transport has made them promising candidates in drug delivery for an array of diseases. Despite several research and review papers describing the salient features of exosomes as nanocarriers for drug delivery, there are no FDA-approved commercial therapeutics based on exosomes. Several fundamental challenges, such as the large-scale production and reproducibility of batches, have hindered the bench-to-bedside translation of exosomes. In fact, compatibility and poor drug loading sabotage the possibility of delivering several drug molecules. This review provides an overview of the challenges and summarizes the potential solutions/approaches to facilitate the clinical development of exosomal nanocarriers.

Injectable hydrogels for sustained delivery of extracellular vesicles in cartilage regeneration

Extracellular vesicles (EVs) are a population of small vesicles secreted by essentially all cell types, containing a wide variety of biological macromolecules. Due to their intrinsic capabilities for efficient intercellular communication, they are involved in various aspects of cellular functioning. In the past decade, EVs derived from stem cells attracted interest in the field of regenerative medicine. Owing to their regenerative properties, they have great potential for use in tissue repair, in particular for tissues with limited regenerative capabilities such as cartilage. The maintenance of articular cartilage is dependent on a precarious balance of many different components that can be disrupted by the onset of prevalent rheumatic diseases. However, while cartilage is a tissue with strong mechanical properties that can withstand movement and heavy loads for years, it is virtually incapable of repairing itself after damage has occurred. Stem cell-derived EVs (SC-EVs) transport regenerative components such as proteins and nucleic acids from their parental cells to recipient cells, thereby promoting cartilage healing. Many possible pathways through which SC-EVs execute their regenerative function have been reported, but likely there are still numerous other pathways that are still unknown. This review discusses various preclinical studies investigating intra-articular injections of free SC-EVs, which, while often promoting chondrogenesis and cartilage repair in vivo, showed a recurring limitation of the need for multiple administrations to achieve sufficient tissue regeneration. Potentially, this drawback can be overcome by making use of an EV delivery platform that is capable of sustainably releasing EVs over time. With their remarkable versatility and favourable chemical, biological and mechanical properties, hydrogels can facilitate this release profile by encapsulating EVs in their porous structure. Ideally, the optimal delivery platform can be formed in-situ, by means of an injectable hydrogel that can be administered directly into the affected joint. Relevant research fulfilling these criteria is discussed in detail, including the steps that still need to be taken before injectable hydrogels for sustained delivery of EVs can be applied in the context of cartilage regeneration in the clinic.

Critical Review on the Different Roles of Exosomes in TNBC and Exosomal-Mediated Delivery of microRNA/siRNA/lncRNA and Drug Targeting Signalling Pathways in Triple-Negative Breast Cancer

Triple-negative breast cancer is the most potent metastatic type of breast cancer that can spread to other body parts. Chemotherapy and surgical intervention are the sole treatments for TNBC, owing to the scarcity of therapeutic targets. Manipulation of the membranes as per the desired targets of exosomes has recently gained much attention as a drug delivery method. Despite their known roles in different diseases, very few studies have focused on signalling that triggers the metastasis of triple-negative breast cancer to other body parts by exosomes. This article highlights the significant roles of exosomes associated with TNBC, the involvement of exosomes in breast cancer diagnosis, progression, and the treatment of triple-negative breast cancer by the exosomes as a drug delivery system. This review paper also illustrates the role of exosomes in initiating EMT in breast cancer, including novel signalling.

CAR-T-Derived Extracellular Vesicles: A Promising Development of CAR-T Anti-Tumor Therapy

Extracellular vesicles (EVs) are a heterogenous population of plasma membrane-surrounded particles that are released in the extracellular milieu by almost all types of living cells. EVs are key players in intercellular crosstalk, both locally and systemically, given that they deliver their cargoes (consisting of proteins, lipids, mRNAs, miRNAs, and DNA fragments) to target cells, crossing biological barriers. Those mechanisms further trigger a wide range of biological responses. Interestingly, EV phenotypes and cargoes and, therefore, their functions, stem from their specific parental cells. For these reasons, EVs have been proposed as promising candidates for EV-based, cell-free therapies. One of the new frontiers of cell-based immunotherapy for the fight against refractory neoplastic diseases is represented by genetically engineered chimeric antigen receptor T (CAR-T) lymphocytes, which in recent years have demonstrated their effectiveness by reaching commercialization and clinical application for some neoplastic diseases. CAR-T-derived EVs represent a recent promising development of CAR-T immunotherapy approaches. This crosscutting innovative strategy is designed to exploit the advantages of genetically engineered cell-based immunotherapy together with those of cell-free EVs, which in principle might be safer and more efficient in crossing biological and tumor-associated barriers. In this review, we underlined the potential of CAR-T-derived EVs as therapeutic agents in tumors.

Extracellular Vesicles from Mesenchymal Stem Cells: Towards Novel Therapeutic Strategies for Neurodegenerative Diseases

Neurodegenerative diseases are fatal disorders of the central nervous system (CNS) which currently lack effective treatments. The application of mesenchymal stem cells (MSCs) represents a new promising approach for treating these incurable disorders. Growing evidence suggest that the therapeutic effects of MSCs are due to the secretion of neurotrophic molecules through extracellular vesicles. The extracellular vesicles produced by MSCs (MSC-EVs) have valuable innate properties deriving from parental cells and could be exploited as cell-free treatments for many neurological diseases. In particular, thanks to their small size, they are able to overcome biological barriers and reach lesion sites inside the CNS. They have a considerable pharmacokinetic and safety profile, avoiding the critical issues related to the fate of cells following transplantation. This review discusses the therapeutic potential of MSC-EVs in the treatment of neurodegenerative diseases, focusing on the strategies to further enhance their beneficial effects such as tracking methods, bioengineering applications, with particular attention to intranasal delivery as a feasible strategy to deliver MSC-EVs directly to the CNS in an effective and minimally invasive way. Current progresses and limiting issues to the extent of the use of MSC-EVs treatment for human neurodegenerative diseases will be also revised.

Current Trends and Changes in Use of Membrane Molecular Dynamics Simulations within Academia and the Pharmaceutical Industry

There has been an almost exponential increase in the use of molecular dynamics simulations in basic research and industry over the last 5 years, with almost a doubling in the number of publications each year. Many of these are focused on neurological membranes, and biological membranes in general, applied to the medical industry. A smaller portion have utilized membrane simulations to answer more basic questions related to the function of specific proteins, chemicals or biological processes. This review covers some newer studies, alongside studies from the last two decades, to determine changes in the field. Some of these are basic, while others are more profound, such as multi-component embedded membrane machinery. It is clear that many facets of the discipline remain the same, while the focus on and uses of the technology are broadening in scope and utilization as a general research tool. Analysis of recent literature provides an overview of the current methodologies, covers some of the recent trends or advances and tries to make predictions of the overall path membrane molecular dynamics will follow in the coming years. In general, the overview presented is geared towards the general scientific community, who may wish to introduce the use of these methodologies in light of these changes, making molecular dynamic simulations more feasible for general scientific or medical research.

Extracellular vesicles: Targeting the heart

Cardiovascular diseases rank the highest incidence and mortality worldwide. As the most common type of cardiovascular disease, myocardial infarction causes high morbidity and mortality. Recent studies have revealed that extracellular vesicles, including exosomes, show great potential as a promising cell-free therapy for the treatment of myocardial infarction. However, low heart-targeting efficiency and short plasma half-life have hampered the clinical translation of extracellular vesicle therapy. Currently, four major types of strategies aiming at enhancing target efficiency have been developed, including modifying EV surface, suppressing non-target absorption, increasing the uptake efficiency of target cells, and utilizing a hydrogel patch. This presented review summarizes the current research aimed at EV heart targeting and discusses the challenges and opportunities in EV therapy, which will be beneficial for the development of effective heart-targeting strategies.

A novel surface functionalization platform to prime extracellular vesicles for targeted therapy and diagnostic imaging

Extracellular vesicles (EVs), nanovesicles released by cells to effectively exchange biological information, are gaining interest as drug delivery system. Yet, analogously to liposomes, they show short blood circulation times and accumulation in the liver and the spleen. For tissue specific delivery, EV surfaces will thus have to be functionalized. We present a novel platform for flexible modification of EVs with target-specific ligands based on the avidin-biotin system. Genetic engineering of donor cells with a glycosylphosphatidylinositol-anchored avidin (GPI-Av) construct allows the isolation of EVs displaying avidin on their surface, functionalized with any biotinylated ligand. For proof of concept, GPI-Av EVs were modified with i) a biotinylated antibody or ii) de novo designed and synthesized biotinylated ligands binding carbonic anhydrase IX (CAIX), a membrane associated enzyme overexpressed in cancer. Functionalized EVs showed specific binding and uptake by CAIX-expressing cells, demonstrating the power of the system to prepare EVs for cell-specific drug delivery.

Strategies and challenges for non-viral delivery of non-coding RNAs to the heart

Non-coding RNAs (ncRNAs), such as miRNAs and long non-coding RNAs (lncRNAs) have been reported as regulators of cardiovascular pathophysiology. Their transient effect and diversified mechanisms of action offer a plethora of therapeutic opportunities for cardiovascular diseases (CVDs). However, physicochemical RNA features such as charge, stability, and structural organization hinder efficient on-target cellular delivery. Here, we highlight recent preclinical advances in ncRNA delivery for the cardiovascular system using non-viral approaches. We identify the unmet needs and advance possible solutions towards clinical translation. Finding the optimal delivery vehicle and administration route is vital to improve therapeutic efficacy and safety; however, given the different types of ncRNAs, this may ultimately not be frameable within a one-size-fits-all approach.

Extracellular vesicles: emerging anti-cancer drugs and advanced functionalization platforms for cancer therapy

Increasing evidences show that unmodified extracellular vesicles (EVs) derived from various cells can effectively inhibit the malignant progression of different types of tumors by delivering the bioactive molecules. Therefore, EVs are expected to be developed as emerging anticancer drugs. Meanwhile, unmodified EVs as an advanced and promising nanocarrier that is frequently used in targeted delivery therapeutic cargos and personalized reagents for the treatment and diagnosis of cancer. To improve the efficacy of EV-based treatments, researchers are trying to engineering EVs as an emerging nanomedicine translational therapy platform through biological, physical and chemical approaches, which can be broaden and altered to enhance their therapeutic capability. EVs loaded with therapeutic components such as tumor suppressor drugs, siRNAs, proteins, peptides, and conjugates exhibit significantly enhanced anti-tumor effects. Moreover, the design and preparation of tumor-targeted modified EVs greatly enhance the specificity and effectiveness of tumor therapy, and these strategies are expected to become novel ideas for tumor precision medicine. This review will focus on reviewing the latest research progress of functionalized EVs, clarifying the superior biological functions and powerful therapeutic potential of EVs, for researchers to explore new design concepts based on EVs and build next-generation nanomedicine therapeutic platforms.

Can Extracellular Vesicles as Drug Delivery Systems Be a Game Changer in Cardiac Disease?

Cardiac diseases such as myocardial infarction and heart failure have been the leading cause of death worldwide for more than 20 years, and new treatments continue to be investigated. Heart transplantation, a curative treatment for severe cardiac dysfunction, is available to only a small number of patients due to the rarity of donors and high costs. Cardiac regenerative medicine using embryonic stem cells and induced pluripotent stem cells is expected to be a new alternative to heart transplantation, but it has problems such as induction of immune response, tumor formation, and low survival rate of transplanted cells. On the other hand, there has been a focus on cell-free therapy using extracellular vesicles (EVs) due to their high biocompatibility and target specificity. Exosomes, one type of EV, play a role in the molecular transport system in vivo and can be considered a drug delivery system (DDS) innate to all living things. Exosomes contain nucleic acids and proteins, which are transported from secretory cells to recipient cells. Molecules in exosomes are encapsulated in a lipid bilayer, which allows them to exist stably in body fluids without being affected by nuclease degradation enzymes. Therefore, the therapeutic use of exosomes as DDSs has been widely explored and is being used in clinical trials and other clinical settings. This review summarizes the current topics of EVs as DDSs in cardiac disease.