Advancements and Insights in Exosome-Based Therapies for Wound Healing: A Comprehensive Systematic Review (2018-June 2023)

Exosomes: A Comprehensive Review for the Practicing Dermatologist

This clinical review examines what is known about exosomes and their applicability to aesthetic dermatology. Exosomes are extracellular vesicles with crucial roles in intercellular communication. Their biogenesis is complex and not completely understood, but they are generally formed intracellularly in the endosomal compartment of a cell or through direct plasma membrane release. Several mechanisms of exosome uptake have been described and are dependent on the molecular characteristics of the recipient cell and exosome membrane. Furthermore, there are a multitude of exosome isolation and characterization techniques, each with their own potential advantages and disadvantages. Exosomes have demonstrated promise in preclinical models across various domains of aesthetic dermatology, including as anti-aging and anti-inflammatory therapies and as therapeutics for wound healing, scar reduction, and hair regeneration. However, clinical studies are lacking, and there are substantial safety concerns, such as the potential risk of infections, unwanted inflammatory response, and promotion of malignancy. Further research is needed to develop more precise analytical techniques to better understand the composition of exosomes, their safety profiles, and their potential applications to patient care.

Immunoregulatory role of exosomal circRNAs in the tumor microenvironment

As cancer incidence and mortality rates rise, there is an urgent need to develop effective immunotherapy strategies. Circular RNA (circRNA), a newly identified type of non-coding RNA, is abundant within cells and can be released via exosomes, facilitating communication between cells. Studies have demonstrated that exosomal circRNAs can alter the tumor microenvironment and modulate immune responses by influencing the functions of T cells, natural killer (NK) cells, and macrophages, thereby enabling tumors to evade the immune system. Moreover, exosomal circRNAs show potential as diagnostic biomarkers and therapeutic targets for cancer. This review summarizes the regulatory roles of exosomal circRNAs in immune cells and their potential applications in cancer progression and treatment, highlighting their promise in improving cancer immunotherapy. Future research should concentrate on understanding the mechanisms of key exosomal circRNAs and developing targeted immunotherapy methods.

Exosomes Exposed: Overview Systematic Review on Evidence Versus Expectation in Aesthetic and Regenerative Medicine

INTRODUCTION

Exosomes, diminutive extracellular vesicles, are integral to intercellular communication, harbouring potential for applications in regenerative medicine and aesthetic interventions. The field, however, grapples with the complexities of harmonising exosome characterisation protocols and safeguarding therapeutic integrity.

METHODOLOGY

In this scholarly overview, systematic adherence to the Cochrane Collaboration and Preferred Reporting Items for Overviews of Reviews guidelines was observed, scrutinising the congruence of exosome-related therapies with the Minimal Information for Studies of Extracellular Vesicles standards delineated by the International Society for Extracellular Vesicles, alongside criteria set forth by the International Society for Cell Therapy and the International Society for Stem Cell Research. A meticulous search strategy spanning databases such as PubMed, Scopus, Web of Science, EMBASE, and Cochrane database was employed to encapsulate studies pertinent to the isolation, characterisation, and functional assessment of exosomes.

RESULTS

The initial search yielded 225 articles, of which 17 systematic reviews were selected based on predefined criteria, encompassing 556 primary studies. Notwithstanding the acknowledged therapeutic promise of exosome modalities, the synthesis illuminated a prevalent deficiency in adherence to established reporting and experimental benchmarks, notably in exosome source characterisation and bioactive constituent delineation. A critical appraisal employing the AMSTAR-2 tool underscored a pervasive shortfall in methodological rigour.

CONCLUSION

This review accentuates the imperative for stringent methodological standardisation within exosome research to fortify the validity and reproducibility of empirical findings. Amidst the burgeoning therapeutic optimism, the discipline must rectify methodological disparities and comply with regulatory mandates, ensuring the ethically sound and scientifically robust advancement of exosome-based therapeutic modalities.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article.  For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Isolation, Expansion, and Characterization of Rat Hair Follicle Stem Cells and Their Secretome: Insights into Wound Healing Potential

Background: Stem cells are capable of self-renewal and differentiation into various specialized cells, making them a potential therapeutic option in regenerative medicine. This study establishes a comprehensive methodology for isolating, culturing, and characterizing rat hair follicle stem cells. Methods and Results: Hair follicles were harvested from Sprague-Dawley rats and subjected to two different isolation techniques. Immunohistochemical analysis and real-time PCR confirm the expression of specific surface markers and genes, validating the cells' identity. Growth kinetics, colony formation units (CFU), and tri-differentiation capacity were also assessed. Additionally, the cells' secretome was analyzed, regarding its content in biofactors with wound healing properties. Conclusions: These findings highlight the potential of these cells as a valuable cell source for skin regeneration applications. They contribute to advancing our understanding of stem cell applications in regenerative medicine and hold promise for therapeutic interventions in various clinical contexts, aligning with broader research on the diverse capabilities of hair follicle stem cells.

Applications of mesenchymal stem cell-exosome components in wound infection healing: new insights

The healing process at a wound is made up of many types of cells, growth factors, the extracellular matrix, nerves and blood vessels all interacting with each other in complex and changing ways. Microbial colonization and proliferation are possible at the place of injury, which makes infection more likely. Because of this, any cut has a chance of getting an infection. Researchers have found that wound infections make patients more upset and cost the healthcare system a lot of money. Surgical site infections happen a lot to people who have recently had surgery. This study shows that such surgical infection is linked to a high rate of illness and death. This is shown by the fact that 25% of patients get serious sepsis and need to be transferred to an intensive care unit. In both animal models and people, mesenchymal stem cells (MSCs) play an active role in all stages of wound healing and have positive effects. Exosomes are one of the main things MSCs release. They have effects that are similar to those of the parent MSCs. Various effector proteins, messenger RNA and microRNAs can be transported by extracellular vesicles to control the activity of target cells. This has a big impact on the healing process. These results suggest that using MSC-exosomes as a new type of cell-free therapy could be a better and safer option than whole cell therapy. This review is mostly about how to use parts of MSC-exosomes to help wound infections heal.

Enhancing the wound healing process through local injection of exosomes derived from blood serum: An in vitro and in vivo assessment

Introduction

The skin plays a crucial role as a protective barrier against external factors, but disruptions to its integrity can lead to wound formation and hinder the natural healing process. Scar formation and delayed wound healing present significant challenges in skin injury treatment. While alternative approaches such as skin substitutes and tissue engineering exist, they are often limited in accessibility and cost. Exosomes have emerged as a potential solution for wound healing due to their regenerative properties.

Methods

In this study, exosomes were isolated from human blood serum using a kit. The exosomes were characterized, and their effects on cell migration were assessed in vitro. Additionally, the wound healing capacity of exosomes was evaluated in vivo using a rat full-thickness wound model.

Results

Our in vitro findings revealed that exosomes significantly promoted cell migration. In vivo experiments demonstrated that the injection of exosomes at different areas of the wound accelerated the wound healing process, resulting in wound closure, collagen synthesis, vessel formation, and angiogenesis in the wound area. These results suggest that exosomes have a promising therapeutic potential for expediting wound healing and minimizing scar formation.

Conclusions

The findings of this study highlight the potential of exosomes as a novel approach for enhancing wound healing. Exosomes showed positive effects on both cell migration and wound closure in in vitro and in vivo studies, suggesting their potential use as a regenerative therapy for skin injuries. Further research is needed to fully understand the mechanisms underlying the beneficial effects of exosomes on wound healing and to optimize their application in clinical settings.

Functional biomacromolecules-based microneedle patch for the treatment of diabetic wound

Diabetic wounds are a common complication of diabetes. The prolonged exposure to high glucose and oxidative stress in the wound environment increases the risk of bacterial infection and abnormal angiogenesis, leading to amputation. Microneedle patches have shown promise in promoting the healing of diabetic wounds through transdermal drug delivery. These patches target the four main aspects of diabetic wound treatment: hypoglycemia, antibacterial action, inflammatory regulation, and tissue regeneration. By overcoming the limitations of traditional administration methods, microneedle patches enable targeted therapy for deteriorated tissues. The design of these patches extends beyond the selection of needle tip material and biomacromolecule encapsulated drugs; it can also incorporate near-infrared rays to facilitate cascade reactions and treat diabetic wounds. In this review, we comprehensively summarize the advantages of microneedle patches compared to traditional treatment methods. We focus on the design and mechanism of these patches based on existing experimental articles in the field and discuss the potential for future research on microneedle patches.

Platelet-derived extracellular vesicles: a new-generation nanostructured tool for chronic wound healing

Chronic nonhealing wounds pose a serious challenge to regaining skin function and integrity. Platelet-derived extracellular vesicles (PEVs) are nanostructured particles with the potential to promote wound healing since they can enhance neovascularization and cell migration and reduce inflammation and scarring. This work provides an innovative overview of the technical laboratory issues in PEV production, PEVs' role in chronic wound healing and the benefits and challenges in its clinical translation. The article also explores the challenges of proper sourcing, extraction techniques and storage conditions, and discusses the necessity of further evaluations and combinational therapeutics, including dressing biomaterials, M2-derived exosomes, mesenchymal stem cells-derived extracellular vesicles and microneedle technology, to boost their therapeutic efficacy as advanced strategies for wound healing.

The Effect of Local Purified Exosome Product, Stem Cells, and Tacrolimus on Neurite Extension

PURPOSE

The combination of cellular and noncellular treatments has been postulated to improve nerve regeneration through a processed nerve allograft. This study aimed to evaluate the isolated effect of treatment with purified exosome product (PEP), mesenchymal stem cells (MSCs), and tacrolimus (FK506) alone and in combination when applied in decellularized allografts.

METHODS

A three-dimensional in vitro-compartmented cell culture system was used to evaluate the length of regenerating neurites from the neonatal dorsal root ganglion into the adjacent peripheral nerve graft. Decellularized nerve allografts were treated with undifferentiated MSCs, 5% PEP, 100 ng/mL FK506, PEP and FK506 combined, or MSCs and FK506 combined (N = 9/group) and compared with untreated nerve autografts (positive control) and nerve allografts (negative control). Neurite extension was measured to quantify nerve regeneration after 48 hours, and stem cell viability was evaluated.

RESULTS

Stem cell viability was confirmed in all MSC-treated nerve grafts. Treatments with PEP, PEP + FK506, and MSCs + FK506 combined were found to be superior to untreated allografts and not significantly different from autografts. Combined PEP and FK506 treatment resulted in the greatest neurite extension. Treatment with FK506 and MSCs was significantly superior to MSC alone. The combined treatment groups were not found to be statistically different.

CONCLUSIONS

Although all treatments improved neurite outgrowth, treatments with PEP, PEP + FK506, and MSCs + FK506 combined had superior neurite growth compared with untreated allografts and were not found to be significantly different from autografts, the current gold standard.

CLINICAL RELEVANCE

Purified exosome product, a cell-free exosome product, is a promising adjunct to enhance nerve allograft regeneration, with possible future avenues for clinical translation.