Activated Platelet-Derived Vesicles for Efficient Hemostatic Activity

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.

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.

Platelet Vesicles Synergetic with Biosynthetic Cellulose Aerogels for Ultra-Fast Hemostasis and Wound Healing

Achieving hemostasis in penetrating and irregular wounds is challenging because the hemostasis factor cannot arrive at the bleeding site, and substantial bleeding will wash away the blood clot. Since the inherently gradual nature of blood clot formation takes time, a physical barrier is needed before blood clot formation. Herein, an ultra-light and shape memory hemostatic aerogel consisting of oxidized bacterial cellulose (OBC) and platelet extracellular vesicles (pVEs) is reported. The OBC-pVEs aerogel provides a physical barrier for the bleeding site by self-expansion, absorbing the liquid from blood to concentrate platelets and clotting factors and accelerating the clot formation by activating platelets and transforming fibrinogen into fibrin. In the rat liver and tail injury models, the blood loss decreases by 73% and 59%, and the bleeding times are reduced by 55% and 62%, respectively. OBC-pVEs aerogel has also been shown to accelerate wound healing. In conclusion, this work introduces an effective tool for treating deep, non-compressible, and irregular wounds and offers valuable strategies for trauma bleeding and wound treatment.

Platelets, Protean Cells with All-Around Functions and Multifaceted Pharmacological Applications

Platelets, traditionally known for their roles in hemostasis and coagulation, are the most prevalent blood component after erythrocytes (150,000-400,000 platelets/μL in healthy humans). However, only 10,000 platelets/μL are needed for vessel wall repair and wound healing. Increased knowledge of the platelet's role in hemostasis has led to many advances in understanding that they are crucial mediators in many other physiological processes, such as innate and adaptive immunity. Due to their multiple functions, platelet dysfunction is involved not only in thrombosis, mediating myocardial infarction, stroke, and venous thromboembolism, but also in several other disorders, such as tumors, autoimmune diseases, and neurodegenerative diseases. On the other hand, thanks to their multiple functions, nowadays platelets are therapeutic targets in different pathologies, in addition to atherothrombotic diseases; they can be used as an innovative drug delivery system, and their derivatives, such as platelet lysates and platelet extracellular vesicles (pEVs), can be useful in regenerative medicine and many other fields. The protean role of platelets, from the name of Proteus, a Greek mythological divinity who could take on different shapes or aspects, is precisely the focus of this review.

Characterization and Therapeutic Use of Extracellular Vesicles Derived from Platelets

Autologous blood products, such as platelet-rich plasma (PRP), are gaining increasing interest in different fields of regenerative medicine. Although growth factors, the main components of PRP, are thought to stimulate reparation processes, the exact mechanism of action and main effectors of PRP are not fully understood. Plasma contains a high amount of extracellular vesicles (EVs) produced by different cells, including anucleated platelets. Platelet-derived EVs (PL-EVs) are the most abundant type of EVs in circulation. Numerous advantages of PL-EVs, including their ability to be released locally, their ease of travel through the body, their low immunogenicity and tumourigenicity, the modulation of signal transduction as well as the ease with which they can be obtained, has attracted increased attention n. This review focuses briefly on the biological characteristics and isolation methods of PL-EVs, including exosomes derived from platelets (PL-EXOs), and their involvement in the pathology of diseases. Evidence that shows how PL-EVs can be used as a novel tool in medicine, particularly in therapeutic and regenerative medicine, is also discussed in this review.

Extracellular Vesicles in Skin Wound Healing

Each year, millions of individuals suffer from a non-healing wound, abnormal scarring, or injuries accompanied by an infection. For these cases, scientists are searching for new therapeutic interventions, from which one of the most promising is the use of extracellular vesicles (EVs). Naturally, EV-based signaling takes part in all four wound healing phases: hemostasis, inflammation, proliferation, and remodeling. Such an extensive involvement of EVs suggests exploiting their action to modulate the impaired healing phase. Furthermore, next to their natural wound healing capacity, EVs can be engineered for better defined pharmaceutical purposes, such as carrying specific cargo or targeting specific destinations by labelling them with certain surface proteins. This review aims to promote scientific awareness in basic and translational research of EVs by summarizing the current knowledge about their natural role in each stage of skin repair and the most recent findings in application areas, such as wound healing, skin regeneration, and treatment of dermal diseases, including the stem cell-derived, plant-derived, and engineered EVs.

Platelet-Derived Extracellular Vesicles for Regenerative Medicine

Extracellular vesicles (EVs) present a great potential for the development of new treatments in the biomedical field. To be used as therapeutics, many different sources have been used for EVs obtention, while only a few studies have addressed the use of platelet-derived EVs (pEVs). In fact, pEVs have been shown to intervene in different healing responses, thus some studies have evaluated their regenerative capability in wound healing or hemorrhagic shock. Even more, pEVs have proven to induce cellular differentiation, enhancing musculoskeletal or neural regeneration. However, the obtention and characterization of pEVs is widely heterogeneous and differs from the recommendations of the International Society for Extracellular Vesicles. Therefore, in this review, we aim to present the main advances in the therapeutical use of pEVs in the regenerative medicine field while highlighting the isolation and characterization steps followed. The main goal of this review is to portray the studies performed in order to enhance the translation of the pEVs research into feasible therapeutical applications.

Platelet Extracellular Vesicles: Beyond the Blood

Extracellular vesicles (EVs) are a means of cell-to-cell communication and can facilitate the exchange of a broad array of molecules between adjacent or distant cells. Platelets are anucleate cells derived from megakaryocytes and are primarily known for their role in maintaining hemostasis and vascular integrity. Upon activation by a variety of agonists, platelets readily generate EVs, which were initially identified as procoagulant particles. However, as both platelets and their EVs are abundant in blood, the role of platelet EVs in hemostasis may be redundant. Moreover, findings have challenged the significance of platelet-derived EVs in coagulation. Looking beyond hemostasis, platelet EV cargo is incredibly diverse and can include lipids, proteins, nucleic acids, and organelles involved in numerous other biological processes. Furthermore, while platelets cannot cross tissue barriers, their EVs can enter lymph, bone marrow, and synovial fluid. This allows for the transfer of platelet-derived content to cellular recipients and organs inaccessible to platelets. This review highlights the importance of platelet-derived EVs in physiological and pathological conditions beyond hemostasis.