Allogeneic Platelet-Rich Plasma: Is It Safe and Effective for Wound Repair?

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.

Standardized Informed Consent Form for Clinicians Administering Platelet-Rich Plasma

Introduction When it comes to medico-legal malpractice suits, lawyers and insurers tend to focus on informed consent documentation. Unfortunately, there is no standard protocol for obtaining informed consent for the use of platelet-rich plasma (PRP) injections, which might cause problems. This study aimed to mitigate this concern through the development of a standardized informed consent document for PRP injections, grounded in evidence-based practices. Materials and methods An examination of databases was conducted to explore the medico-legal ramifications associated with PRP injections, as well as the broader topic of informed consent, with a particular focus on the context of PRP injections. Moreover, interviews were carried out with healthcare providers and individuals who had received PRP injections within the preceding year, utilizing a semi-structured methodology. Results We developed an evidence-based informed consent document tailored for PRP injections. To guarantee its legal validity, the document underwent review by a legal specialist. Subsequently, our institutions implemented the finalized form for PRP injection procedures over one year. Conclusion A legally valid and evidence-based informed consent form for PRP injections would ensure patient's rights, and encourage open communication and transparency between them and the doctor. Moreover, if a lawsuit were to arise, it would serve as a critical document in the doctor's defense and withstand scrutiny from lawyers and the judiciary.

A Comparative Study on Platelet-Rich Plasma From Elderly Individuals and Young Adults to Treat Pressure Ulcers in Mice

OBJECTIVE

The aim of the present study was to compare the therapeutic effects of activated platelet-rich plasma (PRP) prepared from elderly individuals and young adults to treat pressure ulcers (PUs), and to accumulate a theoretical basis for allogeneic PRP treatment of PUs in elderly patients.

MATERIALS AND METHODS

Whole blood was extracted from elderly individuals aged >65 y and young adult volunteers for PRP preparation, and platelet concentrations in whole blood and PRP were compared. Growth factors released from activated PRP were assayed using the enzyme-linked immunosorbent assay. C57BL/6 mice were divided into three groups: the control saline, elderly-PRP (Group A), and young adult-PRP (Group B). Ischemia-reperfusion injury-induced PUs were established on the backs of mice. PUs were photographed on days 0, 5, and 10 to assess their sizes. Specimens were collected on day 10 and subjected to hematoxylin and eosin and Masson's staining. Immunohistochemical staining for CD31 was conducted to evaluate vascular formation, and cell invasion was assessed using a Transwell assay. The action of PRP on transforming growth factor-beta (TGF-β)-dependent fibroblast activity and epithelial-mesenchymal transition was analyzed using immunofluorescence and Western blotting in vitro.

RESULTS

The platelet concentrations in whole blood and PRP of young adults were significantly higher than that in elderly individuals. The two PRP treatment groups had similar platelet enrichment coefficients of PRP. After activation, PRP from young adults produced significantly higher levels of platelet-derived growth factor, TGF-β, and vascular endothelial growth factor than PRP from elderly individuals (P < 0.05). The concentrations of platelet-derived growth factor, TGF-β, and vascular endothelial growth factor were positively correlated with the platelet concentrations in whole blood and PRP. The effects of PRP in regulating the expressions of TGF-β, α-smooth muscle actin, vimentin, and E-cadherin were observed in vivo and in vitro. The two PRP treatment groups exhibited better wound healing than the control group, as evidenced by more re-epithelialization, higher collagen content, skin fibrosis, and more blood vessel formation over time. Group B exhibited better wound healing than Group A (P < 0.05).

CONCLUSION

PRP exhibits potent wound healing ability in PU therapy, and PRP from young adults is seemingly superior to that from elderly individuals because of a higher concentration of platelets and increased production of growth factors.

Topical applications of heterologous platelet rich plasma (PRP) for refractory gingival lesions in autoimmune blistering diseases

BACKGROUND

Recalcitrant gingival erosions, blisters and desquamative gingivitis are common features in oral autoimmune blistering diseases (AIBD). First line treatments include high-dosage corticosteroids and other immunosuppressive drugs, with several side effects and elevated number of recurrences. Autologous platelet-rich plasma (PRP) has been recently introduced as an alternative treatment and its use seems to be promising and safe.

METHODS

In this study we describe the use of topical application of heterologous PRP in nine patients affected by mucous membrane pemphigoid, with gingival lesions refractory to previous treatments. Topical applications of PRP were performed once a week for 2 months and the endpoint for clinical evaluation was set 3 months after the last session. Oral disease severity score (ODSS) and VAS scores for pain measurement were recorded before and after treatment.

RESULTS

The procedure was painless, well accepted, and free from adverse reactions. All patients (100%) reported a reduction in VAS whereas reduction in ODSS was observed in 89% of patients.

CONCLUSIONS

Within the limits of the study, topical heterologous PRP is a safe and promising procedure to be studied in future controlled randomized trials as adjuvant treatment for refractory gingival lesions in patients with AIBDs.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

Treatment of severe pressure ulcers with protein-enriched filtered platelet-rich plasma (PEFPRP): a possible management

Background: Biological dressings with non-transfusion blood components are among the treatments available for pressure ulcers (PUs). Biological dressings contain active concentrated pro-regenerative molecules that can modify and switch off local inflammatory pathways. This re-establishes the physiological homing, which results in healing. In our study, we used a biological component obtained by ultrafiltration of plasma-platelet concentrate: protein-enriched filtered platelet-rich plasma (PEFPRP) with a higher platelet and higher plasma protein concentration. We tested whether treatment with PEFPRP could improve healing in advanced-stage pressure ulcers with a large surface area. All the patients in this study had a surgical indication but were not able to undergo surgery for various reasons. Materials and methods: Ten patients with severe neurological disability and advanced-stage sacral pressure ulcers were treated with allogenic PEFPRP. The mean lesion surface area at T0 was 13.4 cm2 ( ± 9.8 SD). PEFPRP was derived from allogenic plasma-platelet apheresis that had been pre-ultrafiltered with a ProSmart™ filter (Medica, Italy) to obtain a concentration after filtration of the plasma protein (12-16 g/dL) and platelet (1-1.2 x 106 microL). Results and Conclusion: All cases showed a reduction in the surface area of the pressure ulcer and in the Pressure Ulcer Scale for Healing (PUSH) score. The mean reduction values at week 6 were as follows: -52% for surface area and -21% for PUSH. Rapid wound healing is fundamental to avoid infections and improve patients' quality of life. This blood component builds new tissue by creating a new extracellular matrix. This, in turn, promotes rapid restoration of the three-dimensional structure of the tissue necessary for healing deeper wounds. PEFPRP shrinks the PU and improves its morphological features (reducing undermining and boosting granulation tissue). PEFPRP also promotes tissue restoration, obtaining an optimal scar. It is a safe and feasible treatment, and these preliminary results support the use of PEFPRP in the treatment of pressure ulcers. PEFPRP dressings could be integrated in the standard treatment of advanced-stage PU.

Mini-Review: Tendon-Exposed Wound Treatments

BACKGROUND

Tendon-exposed wounds are complex injuries with challenging reconstructions and no unified treatment mode. Furthermore, insufficient tissue volume and blood circulation disorders affect healing, which increases pain for the patient and affects their families and caretakers.

REVIEW

As modern medicine advances, considerable progress has been made in understanding and treating tendon-exposed wounds, and current research encompasses both macro-and micro-studies. Additionally, new treatment methods have emerged alongside the classic surgical methods, such as new dressing therapies, vacuum sealing drainage combination therapy, platelet-rich plasma therapy, and live-cell bioengineering.

CONCLUSIONS

This review summarizes the latest treatment methods for tendon-exposed wounds to provide ideas and improve their treatment.

Clinical Study of Platelet-Rich Plasma (PRP) for Lower Extremity Venous Ulcers: A Meta-Analysis and Systematic Review

To systematically evaluate the clinical effects of platelet-rich plasma in the treatment of lower limb venous ulcers by applying a meta-analysis method. The Pubmed, Cochrance Library, Embase, and OVID EBM Reviews databases were searched for the search terms'platelet-rich plasma" or "Plasma, Platelet-Rich" or "Platelet Rich Plasma" and "lower extremity venous ulcers' or "Leg Ulcers' or "Ulcer, Leg", and a meta-analysis was performed on the published research literature on platelet-rich plasma for lower extremity venous ulcers from January 1900 to April 2021. The outcome indicators were: post-treatment trauma area and healing rate. Revman 5.3 statistical software was applied for meta-analysis. A total of 294 patients with lower extremity venous ulcers were included in six publications, including 148 patients in the experimental group treated with PRP versus 146 patients in the control group treated with conventional therapy. There was a statistically significant difference in the Formula of an ellipse at the end of treatment (CM²) between the experimental group and the control group, with a mean difference of -1.19 (95% CI -1.80 to -0.58, P = .0001; 6 studies, 294 participants moderate quality of evidence). The difference between the healing rate of the experimental group and the control group was statistically significant, with a risk ratio (RR) of 5.73 (95% CI 3.29 - 9.99, P < .00001; 5 studies, 248 participants moderate quality of evidence).There may be publication bias for both Formula of an ellipse at the end of treatment and healing rate. This comprehensive meta-analysis of available evidence suggests that the application of PRP for lower extremity venous ulcers accelerates the wound healing process and improves wound healing rates.

Engineering homologous platelet-rich plasma, platelet-rich plasma-derived exosomes, and mesenchymal stem cell-derived exosomes-based dual-crosslinked hydrogels as bioactive diabetic wound dressings

The management of diabetic wounds remains a critical therapeutic challenge. Platelet-rich plasma (PRP) gel, PRP-derived exosomes (PRP-Exos), and mesenchymal stem cell-derived exosomes (MSC-Exos) have demonstrated therapeutic potential in wound treatment. Unfortunately, their poor mechanical properties, the short half-lives of growth factors (GFs), and the burst release of GFs and exosomes have limited their clinical applications. Furthermore, proteases in diabetic wounds degrade GFs, which hampers wound repair. Silk fibroin is an enzyme-immobilization biomaterial that could protect GFs from proteases. Herein, we developed novel dual-crosslinked hydrogels based on silk protein (SP) (sericin and fibroin), including SP@PRP, SP@MSC-Exos, and SP@PRP-Exos, to promote diabetic wound healing synergistically. SP@PRP was prepared from PRP and SP using calcium gluconate/thrombin as agonist, while SP@PRP-Exos and SP@MSC-Exos were derived from exosomes and SP with genipin as crosslinker. SP provided improved mechanical properties and enabled the sustained release of GFs and exosomes, thereby overcoming the limitations of PRP and exosomes in wound healing. The dual-crosslinked hydrogels displayed shear-induced thinning, self-healing, and eradication of microbial biofilms in a bone-mimicking environment. In vivo, the dual-crosslinked hydrogels contributed to faster diabetic wound healing than PRP and SP by upregulating GFs expression, down-regulating matrix metalloproteinase-9 expression, and by promoting an anti-NETotic effect, angiogenesis, and re-epithelialization. Hence, these dual-crosslinked hydrogels have the potential to be translated into a new generation of diabetic wound dressings.

Expanding applications of allogeneic platelets, platelet lysates, and platelet extracellular vesicles in cell therapy, regenerative medicine, and targeted drug delivery

Platelets are small anucleated blood cells primarily known for their vital hemostatic role. Allogeneic platelet concentrates (PCs) collected from healthy donors are an essential cellular product transfused by hospitals to control or prevent bleeding in patients affected by thrombocytopenia or platelet dysfunctions. Platelets fulfill additional essential functions in innate and adaptive immunity and inflammation, as well as in wound-healing and tissue-repair mechanisms. Platelets contain mitochondria, lysosomes, dense granules, and alpha-granules, which collectively are a remarkable reservoir of multiple trophic factors, enzymes, and signaling molecules. In addition, platelets are prone to release in the blood circulation a unique set of extracellular vesicles (p-EVs), which carry a rich biomolecular cargo influential in cell-cell communications. The exceptional functional roles played by platelets and p-EVs explain the recent interest in exploring the use of allogeneic PCs as source material to develop new biotherapies that could address needs in cell therapy, regenerative medicine, and targeted drug delivery. Pooled human platelet lysates (HPLs) can be produced from allogeneic PCs that have reached their expiration date and are no longer suitable for transfusion but remain valuable source materials for other applications. These HPLs can substitute for fetal bovine serum as a clinical grade xeno-free supplement of growth media used in the in vitro expansion of human cells for transplantation purposes. The use of expired allogeneic platelet concentrates has opened the way for small-pool or large-pool allogeneic HPLs and HPL-derived p-EVs as biotherapy for ocular surface disorders, wound care and, potentially, neurodegenerative diseases, osteoarthritis, and others. Additionally, allogeneic platelets are now seen as a readily available source of cells and EVs that can be exploited for targeted drug delivery vehicles. This article aims to offer an in-depth update on emerging translational applications of allogeneic platelet biotherapies while also highlighting their advantages and limitations as a clinical modality in regenerative medicine and cell therapies.

Advances and prospects of platelet-rich plasma therapy in veterinary ophthalmology

In the recent decades, there has been a significant uptick on the use of platelet-rich plasma (PRP) as a better alternative for ophthalmologic therapies in pathologies, primarily of the ocular surface. PRP is a class of liquid platelet concentrate containing a supra-physiological concentration of platelets in a relatively small amount of plasma. Its potential to heal various tissues has piqued interest in its therapeutic application as a biomaterial in regenerative medicine. It is currently a popular therapeutic agent in plastic surgery, cardiothoracic surgery, reconstructive surgery, and even oral and maxillofacial surgery. Based on the data from in vitro and in vivo studies, it can be concluded that PRP possesses adequate therapeutic potential in ocular pathologies, especially those involving cornea. In addition, the high concentrations of growth factors (TGF-β, VEGF, EGF) present in the PRP accelerate the healing of the corneal epithelium. PRP has great therapeutic prospects in veterinary ophthalmology as a regenerative therapeutic modality. However, several variables are yet to be defined and standardized that can directly affect the efficacy of PRP application in different ophthalmic conditions. There is a shortage of research on the use of PRP in ocular surface defects compared to the number of studies and reports on the use of autologous and allogeneic serum eye drops. Therefore, a data-driven approach is required to generate consensus/guidelines for the preparation, characterization, and therapeutic use of PRP in veterinary ophthalmology. This review aims to inform readers of the latest research on PRP, including its preparation methods, physiological and biochemical properties, clinical applications in veterinary ophthalmology, and their safety and efficacy.

Sphingosine-1-phosphate derived from PRP-Exos promotes angiogenesis in diabetic wound healing via the S1PR1/AKT/FN1 signalling pathway

Background

Sphingosine-1-phosphate (S1P), a key regulator of vascular homeostasis and angiogenesis, is enriched in exosomes derived from platelet-rich plasma (PRP-Exos). However, the potential role of PRP-Exos-S1P in diabetic wound healing remains unclear. In this study, we investigated the underlying mechanism of PRP-Exos-S1P in diabetic angiogenesis and wound repair.

Methods

Exosomes were isolated from PRP by ultracentrifugation and analysed by transmission electron microscopy, nanoparticle tracking analysis and western blotting. The concentration of S1P derived from PRP-Exos was measured by enzyme-linked immunosorbent assay. The expression level of S1P receptor1-3 (S1PR1-3) in diabetic skin was analysed by Q-PCR. Bioinformatics analysis and proteomic sequencing were conducted to explore the possible signalling pathway mediated by PRP-Exos-S1P. A diabetic mouse model was used to evaluate the effect of PRP-Exos on wound healing. Immunofluorescence for cluster of differentiation 31 (CD31) was used to assess angiogenesis in a diabetic wound model.

Results

In vitro, PRP-Exos significantly promoted cell proliferation, migration and tube formation. Furthermore, PRP-Exos accelerated the process of diabetic angiogenesis and wound closure in vivo. S1P derived from PRP-Exos was present at a high level, and S1PR1 expression was significantly elevated compared with S1PR2 and S1PR3 in the skin of diabetic patients and animals. However, cell migration and tube formation were not promoted by PRP-Exos-S1P in human umbilical vein endothelial cells treated with shS1PR1. In the diabetic mouse model, inhibition of S1PR1 expression at wounding sites decreased the formation of new blood vessels and delayed the process of wound closure. Bioinformatics analysis and proteomics indicated that fibronectin 1 (FN1) was closely related to S1PR1 due to its colocalization in the endothelial cells of human skin. Further study supported that FN1 plays an important role in the PRP-Exos-S1P-mediated S1PR1/protein kinase B signalling pathway.

Conclusions

PRP-Exos-S1P promotes angiogenesis in diabetic wound healing via the S1PR1/protein kinase B/FN1 signalling pathway. Our findings provide a preliminary theoretical foundation for the treatment of diabetic foot ulcers using PRP-Exos in the future.

Secretome of Adipose-Derived Stem Cells Cultured in Platelet Lysate Improves Migration and Viability of Keratinocytes

Chronic wounds depict a silent epidemic challenging medical professionals worldwide. Regenerative medicine uses adipose-derived stem cells (ADSC) in promising new therapies. In this study, platelet lysate (PL) as a xenogen-free substitute for foetal bovine serum (FBS) in ADSC culture was used to create an ADSC secretome containing cytokines for optimal wound healing conditions. The ADSC secretome was tested on keratinocytes for migrational behaviour and viability. Therefore, human ADSC were characterized under FBS (10%) and PL (5% and 10%) substitution, regarding morphology, differentiation, viability, gene and protein expression. ADSC were then cultured in 5% PL and their secretome was used for stimulation of keratinocyte migration and viability. To enhance the effect, ADSC were treated with Epithelial Growth Factor (EGF, 100 ng/mL) and hypoxia (1% O₂). In both PL and FBS groups, ADSC expressed typical stem cell markers. PL induced a significantly higher increase in cell viability compared to FBS substitution. ADSC secretome contained various beneficial proteins which enhance the wound healing capacity of keratinocytes. This could be optimized treating ADSC with hypoxia and EGF. In conclusion, the study shows that ADSC cultivated in 5% PL can effectively support wound healing conditions and can be considered as a promising new therapy for individual treatment of chronic wound disorders.

Autologous Platelet and Extracellular Vesicle-Rich Plasma as Therapeutic Fluid: A Review

The preparation of autologous platelet and extracellular vesicle-rich plasma (PVRP) has been explored in many medical fields with the aim to benefit from its healing potential. In parallel, efforts are being invested to understand the function and dynamics of PVRP that is complex in its composition and interactions. Some clinical evidence reveals beneficial effects of PVRP, while some report that there were no effects. To optimize the preparation methods, functions and mechanisms of PVRP, its constituents should be better understood. With the intention to promote further studies of autologous therapeutic PVRP, we performed a review on some topics regarding PVRP composition, harvesting, assessment and preservation, and also on clinical experience following PVRP application in humans and animals. Besides the acknowledged actions of platelets, leukocytes and different molecules, we focus on extracellular vesicles that were found abundant in PVRP.

Porcine Platelet Lysate Intra-articular Knee Joint Injections for the Treatment of Rabbit Cartilage Lesions and Osteoarthritis

Purpose

At present, autologous platelet-derived therapies such as platelet-rich plasma is widely used in the clinic, but allogeneic and xenogeneic therapies are currently in the research stage, mainly due to their biocompatibility in vivo. Platelet lysates depleted of antigens such as blood cells are a potential solution for allogeneic or xenogeneic applications. Platelet lysates can successfully promote the growth and differentiation of xenogeneic cells in vitro, but in vivo data are not yet available. This study aims to evaluate whether porcine platelet lysate can effectively avoid inflammatory reaction in rabbit knee joint, and then treat cartilage defect and arthritis.

Methods

We developed porcine platelet lysates containing undetectable antigens such as blood cells and complement. For xenogeneic application, platelet lysate was injected into rabbit knee joints to observe joint responses. To examine cartilage repair, osteochondral defects were created in rabbit knee joints. Rabbits were sacrificed three months after treatment with platelet lysate to observe cartilage regeneration and arthritis.

Results

The tissue sections in the rabbit knee joints showed no inflammatory reaction. Furthermore, the injection of platelet lysate was found to effectively inhibit the formation of cartilage arthritis in rabbit knee joints.

Conclusion

Our experimental results show that xenogeneic platelet lysate is a safe and effective method in the treatment of arthritis, which can be used as a research basis for future medical applications. The use of xenogeneic platelet lysate for regenerative therapy in vivo is feasible.

Self-assembled polyelectrolyte complexes of chitosan and fucoidan for sustained growth factor release from PRP enhance proliferation and collagen deposition in diabetic mice

Diabetic wound management is a serious health care challenge due to higher rates of relapse, expensive treatment approaches, and poor healing outcomes. Among cell-based therapies, use of platelet-rich plasma (PRP) has been shown to be effective for diabetic wounds, but its poor shelf-life limits its clinical use. Here, we demonstrate a simple but effective polymer system to increase the shelf-life of PRP by developing a polyelectrolyte complex with dropwise addition of chitosan solution containing PRP by simple mixing at room temperature. Thus, prepared chitosan-fucoidan (CF) carrier complex encapsulated more than 95% of the loaded PRP. The resulting CF/PRP colloids were spherical in shape and ensured extended PRP release up to 72 h at 37 °C. Routine characterization (FT-IR, XRD, SEM) showed the material properties. The biological assays showed that CF complexes were biocompatible while CF/PRP enhanced the proliferation of fibroblasts and keratinocytes via higher Ki67 expression and fibroblast migration. Further investigations using a diabetic mouse model demonstrated significantly higher wound contraction and histopathological observations showed increased fibroblast migration, and collagen and cytokeratin deposition in treatment groups. The results are suggestive of the efficacy of CF/PRP as a cost-effective topical formulation for the sustained delivery of growth factors in treating chronic diabetic wounds.

Role of fibroblasts in wound healing and tissue remodeling on Earth and in space

Wound healing (WH) and the role fibroblasts play in the process, as well as healing impairment and fibroblast dysfunction, have been thoroughly reviewed by other authors. We treat these topics briefly, with the only aim of contextualizing the true focus of this review, namely, the microgravity-induced changes in fibroblast functions involved in WH. Microgravity is a condition typical of spaceflight. Studying its possible effects on fibroblasts and WH is useful not only for the safety of astronauts who will face future interplanetary space missions, but also to help improve the management of WH impairment on Earth. The interesting similarity between microgravity-induced alterations of fibroblast behavior and fibroblast dysfunction in WH impairment on Earth is highlighted. The possibility of using microgravity-exposed fibroblasts and WH in space as models of healing impairment on Earth is suggested. The gaps in knowledge on fibroblast functions in WH are analyzed. The contribution that studies on fibroblast behavior in weightlessness can make to fill these gaps and, consequently, improve therapeutic strategies is considered.

The role of allogeneic platelet-rich plasma in patients with diabetic foot ulcer: Current perspectives and future challenges

The frequency of chronic cutaneous wounds are sharply increasing in aging populations. Patients with age-related diseases, such as diabetes, tumors, renal failure and stroke are prone to soft tissue and skin injury, compounded by slowed healing in aging. Imbalance of wound inflammation, loss of growth factor secretion, and impairment of tissue repair abilities are all possible reasons for failed healing. Therefore, it is vital to explore novel approaches to accelerate wound healing. Platelet-rich plasma (PRP) as a cell therapy has been widely applied for tissue repair and regeneration. PRP promotes wound healing by releasing antimicrobial peptides, growth factors and micro-RNAs. Medical evidence indicates that autologous platelet-rich plasma (au-PRP) can promote wound healing effectively, safely and rapidly. However, its clinical application is usually restricted to patients with chronic cutaneous wounds, generally because of other severe complications and poor clinical comorbidities. Allogeneic platelet-rich plasma (al-PRP), with abundant sources, has demonstrated its superiority in the field of chronic wound treatment. Al-PRP could overcome the limitations of au-PRP and has promising prospects in clinical applications. The aim of this review is to summarize the current status and future challenges of al-PRP in chronic cutaneous wound management. We also summarized clinical cases to further describe the application of al-PRP for chronic wounds in clinical practice.

Platelet Rich Plasma in the Repair of Articular Cartilage Injury: A Narrative Review

OBJECTIVE

This paper reviews the research of platelet-rich plasma (PRP) in articular cartilage injury repair, to assess the mechanism, utilization, and efficacy of PRP in the treatment of articular cartilage injury, hoping to provide a theoretical basis for the clinical application of PRP in the future.

MATERIALS AND METHODS

A comprehensive database search on PRP applications in cartilage repair was performed. Among them, the retrieval time range of PRP in clinical trials of repairing knee cartilage injury was from January 1, 2021 to January 1, 2022. Non-clinical trials and studies unrelated to cartilage injury were excluded.

RESULT

PRP can affect inflammation, angiogenesis, cartilage protection, and cellular proliferation and differentiation after articular cartilage injury through different pathways. In all, 13 clinical trials were included in the analysis.

CONCLUSION

PRP is an emergent therapeutic approach in tissue engineering. Most studies reported that PRP has a positive effect on cartilage injury, improving the joint function, meanwhile there is a lack of standardized standards. The technology of PRP in the repair and treatment of articular cartilage injury is worthy of further research.

Progress of Platelet Derivatives for Cartilage Tissue Engineering

Articular cartilage has limited self-regeneration ability for lacking of blood vessels, nerves, and lymph that makes it a great challenge to repair defects of the tissue and restore motor functions of the injured or aging population. Platelet derivatives, such as platelet-rich plasma, have been proved effective, safe, and economical in musculoskeletal diseases for their autologous origin and rich in growth factors. The combination of platelet derivatives with biomaterials provides both mechanical support and localized sustained release of bioactive molecules in cartilage tissue engineering and low-cost efficient approaches of potential treatment. In this review, we first provide an overview of platelet derivatives and their application in clinical and experimental therapies, and then we further discuss the techniques of the addition of platelet derivatives and their influences on scaffold properties. Advances in cartilage tissue engineering with platelet derivatives as signal factors and structural components are also introduced before prospects and concerns in this research field. In short, platelet derivatives have broad application prospects as an economical and effective enhancement for tissue engineering–based articular cartilage repair.

Platelet-rich plasma application in diabetic ulcers: A review

There are 422 million diabetic people in the world. 25% of these individuals are diagnosed with diabetic foot ulcer (DFU). 20% of patients with DFU will suffer amputation of the lower limbs. Following amputation procedures, the mortality rate of patients is over 70% in 5 years. Diabetes has no cure and, therefore, treatment aims to prevent and treat its complications. Autologous platelet-rich plasma (PRP) has been shown to be a therapeutic tool for many types of disorders, including the treatment of DFU. This manuscript aims to carry out a review to provide more knowledge about the efficacy and safety of autologous PRP for wound closure in patients with DFU. The majority of studies included in this review state that PRP promotes improvement of DFU lesions by accelerating tissue healing processes. However, many studies have a small sample size and thus require larger sample range in order to improve robustness of data in the literature.

Allogeneic platelet-derived growth factors local injection in treatment of tennis elbow: a prospective randomized controlled study

PURPOSE

The purpose of this study aimed to evaluate the efficacy of local injection of allogeneic platelet-derived growth factors in treatment of patients with tennis elbow.

PATIENTS AND METHODS

This study included 120 tennis elbow patients randomly divided into two groups. The patients were locally injected with allogeneic growth factors (treatment group) or with normal saline (control group). The outcomes were assessed using Patient-Related Tennis Elbow Evaluation (PRTEE) and quick Disabilities of the Arm, Shoulder and Hand (qDASH) scales. The clinical outcomes were accordingly classified as excellent, good and poor. The patient's satisfaction and adverse effects were also recorded.

RESULTS

There was no statistically significant difference between the two groups regarding the age, gender, dominant arm or the pre-injection scores. At three month follow-up, the reductions in the mean PRTEE and qDASH scores were 88.7% and 70.6% in the treatment group versus 21.8% and 14.9% in the control group, respectively. At the last follow-up, the outcomes in the treatment group were excellent in 85% of patients and good in 15%, versus 8% and 32% in the control group. Overall, 95% were satisfied in the treatment group compared to 25% in control group. Forty patients in the treatment group experienced mild transient post-injection pain.

CONCLUSION

This study strongly suggests that local injection of allogeneic platelet-derived growth factors could be a promising safe treatment option for tennis elbow with significant pain relief, functional improvement and patient's satisfaction. Yet, additional larger studies are needed to assess the durability of these outcomes.