Platelet-rich plasma (PRP): Methodological aspects and clinical applications

Biofunctionalized hydrogel composed of genipin-crosslinked gelatin/hyaluronic acid incorporated with lyophilized platelet-rich fibrin for segmental bone defect repair

Segmental bone defects can arise from trauma, infection, metabolic bone disorders, or tumor removal. Hydrogels have gained attention in the field of bone regeneration due to their unique hydrophilic properties and the ability to customize their physical and chemical characteristics to serve as scaffolds and carriers for growth factors. However, the limited mechanical strength of hydrogels and the rapid release of active substances have hindered their clinical utility and therapeutic effectiveness. With ongoing advancements in material science, the development of injectable and biofunctionalized hydrogels holds great promise for addressing the challenges associated with segmental bone defects. In this study, we incorporated lyophilized platelet-rich fibrin (LPRF), which contains a multitude of growth factors, into a genipin-crosslinked gelatin/hyaluronic acid (GLT/HA-0.5 % GP) hydrogel to create an injectable and biofunctionalized composite material. Our findings demonstrate that this biofunctionalized hydrogel possesses optimal attributes for bone tissue engineering. Furthermore, results obtained from rabbit model with segmental tibial bone defects, indicate that the treatment with this biofunctionalized hydrogel resulted in increased new bone formation, as confirmed by imaging and histological analysis. From a translational perspective, this biofunctionalized hydrogel provides innovative and bioinspired capabilities that have the potential to enhance bone repair and regeneration in future clinical applications.

Decoding the Decade: Exploring the Efficacy of Platelet-Rich Plasma (PRP) in Complex Wound Management - A Comprehensive Study

Introduction

Autologous platelet-rich plasma (PRP) therapy has emerged as a promising regenerative treatment modality, offering potential improvements in healing outcomes through its rich content of growth factors and cytokines. We evaluated the effectiveness of PRP therapy in the management of complex wounds, using a decade-long retrospective analysis of treatments conducted at a tertiary care center from 2010 to 2020. The study introduces and assesses the efficacy of the Sandeep's Technique for Assisted Regeneration of Skin (STARS) in enhancing wound healing and quality of life for patients with complex wounds.

Materials and methods

A prospective interventional study was conducted, involving two phases: the development and initial testing of PRP therapy (2010-2015) and the application and evaluation of the STARS protocol (2015-2020). The study included patients with complex wounds, utilizing autologous PRP prepared through a double spin centrifuge technique. Outcome measures included wound-healing rates, infection management, and complication rates, compared to conventional treatment methods.

Results

The study treated 500 wounds in 432 patients with autologous PRP, noting significant improvements in wound-healing rates, 97.7% had infection control without antibiotics (even in MRSA cases), and all had a good pain control. Histopathological examinations confirmed collagen-rich healing with minimal scarring. The STARS protocol demonstrated the potential of PRP therapy in accelerating wound healing, reducing the need for additional surgical interventions, and enhancing patient outcomes.

Conclusion

PRP therapy, particularly when administered following the STARS protocol, represents a safe, effective, and patient-friendly approach for the management of complex wounds. This study supports the integration of PRP therapy into regenerative care strategies, suggesting a shift toward more innovative and efficacious treatments in wound management.

A primer on the restorative therapies for erectile dysfunction: a narrative review

INTRODUCTION

Erectile dysfunction (ED) is a common condition that affects millions worldwide. Patients and urologists alike are seeking alternative therapies that can provide long-lasting results in the treatment of ED. This review provides a comprehensive overview of restorative treatments available for ED, such as platelet-rich plasma, stem cell therapy, and shockwave therapy.

OBJECTIVE

The aim of this narrative review is to provide a primer for urologists and general practitioners on the basics of implementing ED restorative therapies in their practice.

METHODS

The PubMed, MEDLINE, and Google Scholar databases were searched for articles in the English language through August 31, 2023, that included key terms such as "erectile dysfunction," "restorative therapy," "shockwave therapy," "platelet-rich plasma," "stem cell therapy," and "stromal vascular fraction." Reference lists of selected studies were manually reviewed to find articles not identified by the initial database search.

RESULTS

Shockwave therapy has demonstrated effectiveness in treating ED, with devices like the Medispec ED1000 and Storz Duolith showing statistically significant improvements in patient scores for International Index of Erectile Function (IIEF)-Erectile Function scores in clinical trials. In reported studies of platelet-rich plasma injections, a substantial percentage of patients reached a minimal clinically important difference in the IIEF-Erectile Function scale after treatment. Studies of ED treatment with stem cell therapy, while limited and with small sample sizes, have demonstrated encouraging improvements in patient scores for the abridged 5-item version of the IIEF after treatment.

CONCLUSION

Shockwave, platelet-rich plasma, and stem cell therapies are important, novel, noninvasive restorative treatments for ED that can provide relief for patients wishing to avoid a more invasive approach. While these therapies have shown promising results in clinical trials, more research is required to establish them as standardized and efficacious options in the management of ED.

Laser-mediated Solutions: Breaking Barriers in Transdermal Drug Delivery

Skin diseases pose challenges in treatment due to the skin's complex structure and protective functions. Topical drug delivery has emerged as a preferred method for treating these conditions, offering localized therapy with minimal systemic side effects. However, the skin's barrier properties frequently limit topical treatments' efficacy by preventing drug penetration into deeper skin layers. In recent years, laser-assisted drug delivery (LADD) has gained attention as a promising strategy to overcome these limitations. LADD involves using lasers to create microchannels in the skin, facilitating the deposition of drugs and enhancing their penetration into the target tissue. Several lasers, such as fractional CO2, have been tested to see how well they work at delivering drugs. Despite the promising outcomes demonstrated in preclinical and clinical studies, several challenges persist in implementing LADD, including limited penetration depth, potential tissue damage, and the cost of LADD systems. Furthermore, selecting appropriate laser parameters and drug formulations is crucial to ensuring optimal therapeutic outcomes. Nevertheless, LADD holds significant potential for improving treatment efficacy for various skin conditions, including skin cancers, scars, and dermatological disorders. Future research efforts should focus on optimizing LADD techniques, addressing safety concerns, and exploring novel drug formulations to maximize the therapeutic benefits of this innovative approach. With continued advancements in laser technology and pharmaceutical science, LADD has the potential to revolutionize the field of dermatology and enhance patient care.

The emerging role of biostimulators as an adjunct in facial rejuvenation: A systematic review

INTRODUCTION

Facial aging has long been an area of focus in esthetic surgery. It is the consequence of physiologic and environmental factors, with a trend toward non-surgical modalities. Although volume augmentation has long been a focus of non-surgical facial rejuvenation, there is emerging interest in the use of biostimulators to induce physiologic changes in the skin. This article aimed to provide an overview of this class of therapies.

METHODS

A systematic review regarding the clinical use of biostimulatory agents including platelet-rich plasma (PRP), platelet-rich fibrin (PRF), poly-L-lactic acid (PLLA) and calcium hydroxylapatite (CaHA) in facial rejuvenation was performed using PubMed databases. The protocol was developed following the preferred reporting for items for systematic reviews-protocols guidelines. Included studies matched predetermined criteria according to the employed intervention and outcomes.

RESULTS

The systematic review was performed in September 2023, with the primary search yielding 464 articles. Abstract review resulted in 73 articles of potential relevance. Comprehensive review of the articles and manual reference checks were performed, independently, by 2 authors. This yielded a total of 45 articles that met the inclusion criteria.

CONCLUSIONS

There is an increasing role for non-surgical modalities in facial rejuvenation. Biostimulatory agents may be used as an alternative, or act as an adjunct, to other non-surgical modalities. These agents induce physiologic changes that mitigate facial aging. There is limited, quantifiable data, which fully illustrate the effect in these products. Although these agents are known to illicit inflammatory changes, more controlled studies are needed to better elucidate the biostimulatory capacity of such non-surgical treatments.

Autologous platelet-rich plasma for assisted reproduction

BACKGROUND

Autologous platelet-rich plasma (PRP) consists of plasma and a concentrate of platelets extracted from fresh whole blood of the person being treated. Research has suggested that intrauterine or intraovarian infusion/injection of PRP before embryo transfer may improve endometrial receptivity and response to ovarian stimulation in women undergoing assisted reproduction. We compared these interventions to standard treatment, placebo, or other interventions (mechanical or pharmacological).

OBJECTIVES

To assess the effectiveness and safety of intrauterine and intraovarian infusion/injection of platelet-rich plasma in infertile women undergoing assisted reproductive technology cycles.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group's Specialised Register, CENTRAL, MEDLINE, Embase, and the Epistemonikos database in January 2023. We also searched the reference lists of relevant articles and contacted the trial authors and experts in the field for any additional trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated the application of PRP in the uterine cavity, ovaries, or both versus no intervention, placebo, or any other intervention (either mechanical or pharmacological) in women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles.

DATA COLLECTION AND ANALYSIS

We followed standard methodological procedures recommended by Cochrane, including use of the updated risk of bias tool (RoB 2). The primary outcomes were live birth (or ongoing pregnancy) and miscarriage. The secondary outcomes were clinical pregnancy, complications of the procedure, multiple pregnancy, ectopic pregnancy, fetal growth restriction, preterm delivery, and fetal abnormality. We estimated the average effect of the interventions by fitting a Der Simonian-Laird's random-effects meta-analysis model. We reported pooled odds ratios (ORs) with 95% confidence intervals (CIs). We restricted the primary analyses to trials at low risk of bias for the outcomes and performed sensitivity analyses that included all studies.

MAIN RESULTS

We included 12 parallel-group RCTs that recruited a total of 1069 women. We identified three different comparison groups. Using GRADE, we assessed the certainty of evidence as very low for almost all outcomes. Intrauterine injection/infusion of platelet-rich plasma versus no intervention or placebo Nine studies evaluated intrauterine PRP versus no intervention or placebo. Eight included women with at least two or three previous implantation failures. Only one was assessed at low risk of bias for each outcome. This study provided very low-certainty evidence about the effect of intrauterine PRP injection versus no intervention on live birth (OR 1.10, 95% CI 0.38 to 3.14; 94 women) and miscarriage (OR 0.96, 95% CI 0.13 to 7.09; 94 women). If the likelihood of live birth following no intervention is assumed to be 17%, then the likelihood following intrauterine PRP would be 7% to 40%; and if the risk of miscarriage following no intervention is 4%, then the risk following intrauterine PRP would be 1% to 24%. When we analyzed all studies (regardless of risk of bias), we found very low-certainty evidence about the effect of intrauterine PRP compared with placebo or no intervention on live birth or ongoing pregnancy (OR 2.38, 95% CI 1.16 to 4.86; I² = 54%; 6 studies, 564 women) and miscarriage (OR 1.54, 95% CI 0.59 to 4.01; I² = 0%; 5 studies, 504 women). The study at low risk of bias provided very low-certainty evidence about the effect of intrauterine PRP compared with no intervention on clinical pregnancy (OR 1.55, 95% CI 0.64 to 3.76; 94 women) and ectopic pregnancy (OR 2.94, 95% CI 0.12 to 73.95; 94 women). The synthesis of all studies provided very low-certainty evidence about the effect of intrauterine PRP compared with placebo or no intervention on clinical pregnancy (OR 2.22, 95% CI 1.50 to 3.27; I² = 24%; 9 studies, 824 women), multiple pregnancy (OR 2.68, 95% CI 0.81 to 8.88; I² = 0%; 2 studies, 240 women), and ectopic pregnancy (OR 2.94, 95% CI 0.12 to 73.95; 1 study, 94 women; very low-certainty evidence). Intrauterine infusion of PRP may increase the risk of preterm delivery compared with no intervention (OR 8.02, 95% CI 1.72 to 37.33; 1 study, 120 women; low-certainty evidence). No studies reported pain, infection, allergic reaction, fetal growth restriction, or fetal abnormality. Intrauterine infusion of platelet-rich plasma versus intrauterine infusion of granulocyte colony-stimulating factor Two RCTs evaluated intrauterine PRP versus intrauterine granulocyte colony-stimulating factor (G-CSF); both included women with thin endometrium, and neither was judged at low risk of bias for any outcome. We are uncertain about the effect of intrauterine PRP compared with intrauterine G-CSF on live birth (OR 0.88, 95% CI 0.43 to 1.81; 1 study, 132 women; very low-certainty evidence), miscarriage (OR 1.94, 95% CI 0.63 to 5.96; 1 study, 132 women; very low-certainty evidence), and clinical pregnancy (OR 1.24, 95% CI 0.66 to 2.35; 2 studies, 172 women; very low-certainty evidence). Neither study reported adverse outcomes other than miscarriage. Intraovarian injection of platelet-rich plasma versus no intervention One RCT evaluated PRP injection into both ovaries versus no intervention; it was judged at high risk of bias for the two outcomes it reported. We are uncertain about the effect of intraovarian PRP injection compared with no intervention on ongoing pregnancy (OR 1.09, 95% CI 0.33 to 3.63; 73 women; very low-certainty evidence) and clinical pregnancy (OR 0.90, 95% CI 0.31 to 2.60; 73 women; very low-certainty evidence). The study examined no safety outcomes.

AUTHORS' CONCLUSIONS

We are uncertain about the effect of intrauterine or intraovarian administration of PRP on outcomes of assisted reproduction technology in infertile women. The pooled results should be interpreted with caution. Only one of the 12 included studies was judged at low risk of bias. Other limitations of the included trials were failure to report live birth, poor reporting of methods, lack of prospective protocol registration, low precision due to the small number of enrolled participants, indirectness due to the specific subpopulations and settings studied, and insufficient or absent safety data.

Clinical observation of ultraviolet therapy combined with autologous platelet-rich plasma in the treatment of chronic refractory wounds

Refractory wounds present complex and serious clinical dilemmas in plastic and reconstructive surgeries. Currently, there are no standard guidelines for the treatment of refractory wounds. To observe the clinical effects of ultraviolet (UV) therapy combined with autologous platelet-rich plasma (PRP) on chronic refractory wounds. Between January 2021 and December 2022, 60 inpatients with chronic refractory wounds were enrolled. Twenty patients were assigned to each of control groups 1 and 2 and treatment group according to whether they received PRP or UV treatment. All the patients underwent thorough debridement. Control group 2 received UV radiation. The treatment group underwent UV radiation combined with PRP gel covering the wound. Control group 1 underwent routine dressing changes after surgery, followed by skin grafting or skin key transfer if needed. One month later, we observed the wound healing in the two groups. After 2-4 PRP gel treatments, the wounds of patients in the treatment group healed. The healing time was 25.25 ± 4.93 days, and the dressings were changed 4.15 ± 3.30 times, both of which were better outcomes than in both control groups. In the treatment group, epidermal growth factor (EGF), insulin-like growth factor (IGF), platelet-derived growth factor (PGF), and transforming growth factor β (TGF-β) were slightly higher, and the concentration of vascular endothelial growth factor (VEGF) was significantly higher than in the control group (p < 0.05). PRP combined with UV therapy significantly increased the concentration of wound growth factors, accelerated wound healing, shortened treatment time, reduced treatment costs, and alleviated pain in patients.

Intra-articular injection of platelet lysate-derived extracellular vesicles recovers from knee osteoarthritis in an in vivo rat model

Objective

MSCs and Platelet-Rich Plasma are the main focus in the study of new regenerative treatments aimed to reverse Osteoarthritis (OA). However, extracellular vesicles (EVs) present several advantages to cell-based treatments. Thus, the aim of this study was to compare and evaluate the regenerative potential of MSC-derived EVs (cEVs) and platelet-derived EVs (pEVs) in an OA cartilage rat model.

Design

OA in vivo model was established through injection of 6 mg MIA in the rat knee joints. After 14 and 21 days, OA knee joints were treated with 1 × 1010 particles of pEVs or cEVs. At day 28, the animals were sacrificed, plasma was collected to quantify CTX-II and knee joints were excised to be evaluated by Cone Beam Computed Tomography (CBCT). After decalcification, histology was used to determine the OARSI score and to visualize collagen and glycosaminoglycan content.

Results

pEVs and cEVs samples did not show significant differences per se but they did in terms of regenerative effects on OA knee joints. pEVs-treated knee joints showed better subchondral bone integrity in CT-analysed parameters when compared to cEVs or OA group, showing similar values to the healthy control group. Moreover, OARSI score indicated that pEVs showed a greater OA reversion in knee joints, especially in female rats, and so indicated the analysed histological images.

Conclusions

pEVs are proposed as a viable regeneration treatment for OA since they are not only capable of exerting their regenerative potential on osteoarthritic cartilage, but also outperform cEVs in terms of efficacy, particularly in females.

Significance statement

Osteoarthritis (OA) is one of the most age-related diseases. It is estimated that 500 million people suffer from OA worldwide, representing the principal cause of chronic disability in adults. In the present study we evaluated the therapeutic effect of extracellular vesicles (EVs) from different sources (platelet lysate and human umbilical cord mesenchymal stromal cells) in an in vivo rat model. Our results demonstrate that platelet-derived EVs (pEVs) induce an OA reversion in knee joints, thus evidencing the therapeutic potential of pEVs as cell-free regenerative agents for OA treatment.

The translational potential of this article

Platelet-derived extracellular vesicles (pEVs) offer a promising cell-free therapy option for OA treatment. Their production could be easily standardized and reproduced without extensive platelet harvesting and amplification, thus paving the way for their clinical translation.

Exploring the potential use of platelet rich plasma (PRP) from adult and umbilical cord blood in murine follicle culture

Ovarian follicle culture is a powerful tool to study follicular physiology and has potential applications in clinical and commercial settings. Despite remarkable progress, recreating folliculogenesis in vitro remains challenging for many mammalian species. This study investigates the impact of platelet-rich plasma (PRP) derived from adult blood (human platelet lysate, hPL) and umbilical cord blood (Umbilical cord plasma, UCP) on murine pre-antral follicle culture and oocyte maturation. Pre-antral follicles were cultured individually for 10 days with fetal bovine serum (FBS) serving as the control and two PRP sources (hPL and UCP) and their activated forms (Ac-hPL and Ac-UCP). The results suggest that neither hPL nor UCP, regardless of activation status, improved follicle culture outcomes compared to FBS. Interestingly, activation did not significantly impact the main functional outcomes such as maturation rates, survival, and growth. Oestradiol secretion and oocyte diameter, often considered hallmarks of follicle quality, did not show significant differences between matured and non-matured oocytes across the treatment groups. However, gene expression analysis revealed a significant upregulation of Gdf-9 and Bmp-15 mRNA levels in oocytes from the Ac-UCP group, regardless of maturation stage, suggesting that the accumulation of the mRNA could be due to potential challenges in translation in the Ac-UCP group. In conclusion, this study challenges the hypothesis that PRP, as a serum source, could improve follicle culture outcomes compared to FBS, the gold standard in murine follicle culture. Further research is needed to understand the species-specific effects of PRP and explore other potential factors affecting follicle culture and oocyte quality.

Activation of cell adhesion and migration is an early event of platelet-rich plasma (PRP)-dependent stimulation of human adipose-derived stem/stromal cells

Stem cell therapy is a promising treatment in regenerative medicine. Human adipose-derived stem/stromal cells (hASCs), a type of mesenchymal stem cell, are easy to harvest. In plastic and aesthetic surgery, hASC may be applied in the treatment of fat grafting, wound healing, and scar remodeling. Platelet-rich plasma (PRP) contains various growth factors, including platelet-derived growth factor (PDGF), which accelerates wound healing. We previously reported that PRP promotes the proliferation of hASC via multiple signaling pathways, and we evaluated the effect of PRP on the stimulation of hASC adhesion and migration, leading to the proliferation of these cells. When hASCs were treated with PRP, AKT, ERK1/2, paxillin and RhoA were rapidly activated. PRP treatment led to the formation of F-actin stress fibers. Strong signals for integrin β1, paxillin and RhoA at the cell periphery of RPR-treated cells indicated focal adhesion. PRP promoted cell adhesion and movement of hASC, compared with the control group. Imatinib, an inhibitor of the PDGF receptor tyrosine kinase, inhibited the promotion of PRP-dependent cell migration. PDGF treatment of hASCs also stimulated cell adhesion and migration but to a lesser extent than PRP treatment. PRP promoted the adhesion and the migration of hASC, mediated by the activation of AKT in the integrin signaling pathway. PRP treatment was more effective than PDGF treatment in enhancing cell migration. Thus, the ability of PRPs to promote migration of hASC to enhance cell growth is evident.

Leukoreduced PRP enhanced proliferation and ECM production yet inhibited senescence, inflammation, and multi-differentiation potential of AFSCs by downregulating HMGB1

BACKGROUND

This study assessed the role and potential mechanism of platelet-rich plasma (PRP) in the progression of intervertebral disk degeneration (IVDD).

METHODS

Annulus fibrosus (AF)-derived stem cells (AFSCs) from New Zealand white rabbits received the transfection with high mobility group box 1 (HMGB1) plasmids and the subsequent treatment with bleomycin, 10% leukoreduced PRP or leukoconcentrated PRP. Dying cells were indicated by immunocytochemistry analysis for senescence-associated β-galactosidase (SA-β-gal) staining. The proliferation of these cells was evaluated based on the population doubling time (PDT). The expressions of HMGB1, pro-aging and anti-aging molecules, extracellular matrix (ECM)-related catabolic/anabolic factors, and inflammatory genes at the molecular or transcriptional levels were quantified via Western blot or reverse transcription-quantitative PCR (RT-qPCR). Besides, the adipocytes, osteocytes, and chondrocytes were separately dyed by Oil Red O, Alizarin Red S, and Safranin O staining.

RESULTS

Bleomycin enhanced the senescent morphological changes and increased the PDT and the expressions of SA-β-gal, pro-aging molecules, ECM-related catabolic factors, inflammatory genes, and HMGB1 while suppressing the expressions of anti-aging and anabolic molecules. Leukoreduced PRP reversed the effects of bleomycin and inhibited the differentiation of AFSCs into adipocytes, osteocytes, and chondrocytes. Besides, HMGB1 overexpression offset the roles of leukoreduced PRP in AFSCs.

CONCLUSION

Leukoreduced PRP promotes cell proliferation and ECM production of AFSCs, while inhibiting their senescence, inflammation, and multi-differentiation potentials via downregulating HMGB1 expression.

An Overview of Recent Developments in the Management of Burn Injuries

According to the World Health Organization (WHO), around 11 million people suffer from burns every year, and 180,000 die from them. A burn is a condition in which heat, chemical substances, an electrical current or other factors cause tissue damage. Burns mainly affect the skin, but can also affect deeper tissues such as bones or muscles. When burned, the skin loses its main functions, such as protection from the external environment, pathogens, evaporation and heat loss. Depending on the stage of the burn, the patient's condition and the cause of the burn, we need to choose the most appropriate treatment. Personalization and multidisciplinary collaboration are key to the successful management of burn patients. In this comprehensive review, we have collected and discussed the available treatment options, focusing on recent advances in topical treatments, wound cleansing, dressings, skin grafting, nutrition, pain and scar tissue management.

Use of platelet lysate for in-vitro embryo production and treatment of repeat breeding in cows

Platelet-rich plasma (PRP) is a biological hemocomponent derived from blood after the complete removal of red blood cells and the partial or complete removal of white blood cells to concentrate platelets in an appropriate volume of plasma. Platelets have important growth factors, cytokines, and active metabolites that improve the endometrial environment and positively affect implantation. This study evaluated the effect of the addition of activated PRP (platelets lysate; PL) on in vitro bovine oocyte maturation and embryonic development and the effect of intrauterine (IU) infusion of autologous PL in repeat breeder (RB) cows. Experiment 1 examined the effects of allogeneic PL, fetal calf serum (FCS), mixed PL + FCS, or platelet-poor plasma (PPP) supplementations to in vitro maturation and development media on in vitro oocyte maturation and embryo development in good- and poor-quality oocytes of Japanese Black cows. Experiment 2 examined the IU infusion of autologous PL, 24 h post-insemination, in 21 RB Holstein-Friesian dairy cows. The cleavage rate of good-quality oocytes was higher in the PL group (85.93 ± 2.50%) than in the PPP group (67.16 ± 3.41%) (P < 0.05), while the cleavage rate of the poor-quality oocytes was higher in the PL alone (76.13 ± 4.04%) and mixed PL + FCS treated (73.59 ± 4.22%) groups than in the PPP group (54.64 ± 2.93%) (P < 0.05). The blastocyst rate of the good-quality oocytes was higher in the PL group (40.97 ± 3.03%) than in the FCS (27.97 ± 3.31%) and PPP (25.33 ± 2.15%) groups (P < 0.05). The blastocyst rate of poor-quality oocytes and the hatching rates of both good and poor-quality oocytes showed no significant differences among all groups. The conception rate in the autologous PL-treated group was 41.67% (5/12), while it was 11.11% (1/9) in the control group. The platelets' count in the pregnant PL-treated cows (n = 5; mean ± SEM, 1.07 ± 0.10 × 109/mL) was higher than in the non-pregnant ones (n = 7; 0.67 ± 0.10 × 109/mL) (P < 0.05). In conclusion, allogeneic PL was effective in stimulating the in vitro oocyte maturation and embryonic development in both good and poor-quality bovine oocytes, and post-insemination IU infusion of autologous PL derived from high platelets' count-PRP would be recommended for the treatment of RB cows.

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.

A Novel Wound Therapy Modality: Autologous Wound Edge Dotted Full-Thickness Skin Grafting Improving Diabetic Foot Ulcer Healing

Aim

To explore the therapeutic efficacy of autologous wound edge-dotted full-thickness skin grafting in improving diabetic foot ulcer healing.

Methods

Sixty-three patients were divided into three groups: conventional wound therapy (CWT) (n = 23), platelet-rich plasma (PRP) (n = 20), and graft (n = 20). All participants were followed up for 12 weeks. The therapeutic efficacy of the three different wound treatment modalities was analyzed.

Results

After follow-up, 37 (58.7%) patients showed complete wound re-epithelialization, of which 10 (43.5%) occurred in the CWT group, 14 (70.0%) in the PRP group, and 13 (65.0%) in the graft group. Multivariate Cox analysis showed that the independent predictive factors for ulcer healing were different treatment modalities (graft: HR = 3.214, 95% CI=1.300-7.945, P < 0.05; platelet-rich plasma: HR = 3.075, 95% CI=1.320-7.161, P < 0.01), ABI (HR = 9.917, 95% CI=2.675-36.760, P < 0.01), and TcPO2 (HR = 1.040; 95% CI=1.005-1.076; P < 0.05). Stratified analysis showed that higher ABI in graft group or PRP group had higher wound healing rate (graft group: HR = 3.748, 95% CI=1.210-11.607, P < 0.05; PRP group: HR = 5.029, 95% CI=1.743-14.509, P < 0.05); higher TcPO2 in the graft group had higher wound healing rate (HR = 15.805, 95% CI=4.414-56.594, P < 0.01). Additionally, the wound healing time (P < 0.0167) and cumulative healing rate (P < 0.05) in both the PRP group and graft group were more advantageous. The graft group promotes wound re-epithelialization earlier and faster than in the CWT group and PRP group (P < 0.05). Meanwhile, the graft group had lower medical costs (P < 0.0167).

Conclusion

Autologous wound edge dotted full-thickness skin grafting has a higher cost-performance ratio than traditional diabetic foot ulcer wound care and is worthy of further clinical application.

Research progress of biomaterials and innovative technologies in urinary tissue engineering

Substantial interests have been attracted to multiple bioactive and biomimetic biomaterials in recent decades because of their ability in presenting a structural and functional reconstruction of urinary tissues. Some innovative technologies have also been surging in urinary tissue engineering and urological regeneration by providing insights into the physiological behavior of the urinary system. As such, the hierarchical structure and tissue function of the bladder, urethra, and ureter can be reproduced similarly to the native urinary tissues. This review aims to summarize recent advances in functional biomaterials and biomimetic technologies toward urological reconstruction. Various nanofirous biomaterials derived from decellularized natural tissues, synthetic biopolymers, and hybrid scaffolds were developed with desired microstructure, surface chemistry, and mechanical properties. Some growth factors, drugs, as well as inorganic nanomaterials were also utilized to enhance the biological activity and functionality of scaffolds. Notably, it is emphasized that advanced approaches, such as 3D (bio) printing and organoids, have also been developed to facilitate structural and functional regeneration of the urological system. So in this review, we discussed the fabrication strategies, physiochemical properties, and biofunctional modification of regenerative biomaterials and their potential clinical application of fast-evolving technologies. In addition, future prospective and commercial products are further proposed and discussed.

Current Progress of Platelet-Rich Derivatives in Cartilage and Joint Repairs

In recent years, several types of platelet concentrates have been investigated and applied in many fields, particularly in the musculoskeletal system. Platelet-rich fibrin (PRF) is an autologous biomaterial, a second-generation platelet concentrate containing platelets and growth factors in the form of fibrin membranes prepared from the blood of patients without additives. During tissue regeneration, platelet concentrates contain a higher percentage of leukocytes and a flexible fibrin net as a scaffold to improve cell migration in angiogenic, osteogenic, and antibacterial capacities during tissue regeneration. PRF enables the release of molecules over a longer period, which promotes tissue healing and regeneration. The potential of PRF to simulate the physiology and immunology of wound healing is also due to the high concentrations of released growth factors and anti-inflammatory cytokines that stimulate vessel formation, cell proliferation, and differentiation. These products have been used safely in clinical applications because of their autologous origin and minimally invasive nature. We focused on a narrative review of PRF therapy and its effects on musculoskeletal, oral, and maxillofacial surgeries and dermatology. We explored the components leading to the biological activity and the published preclinical and clinical research that supports its application in musculoskeletal therapy. The research generally supports the use of PRF as an adjuvant for various chronic muscle, cartilage, and tendon injuries. Further clinical trials are needed to prove the benefits of utilizing the potential of PRF.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

A double-edged sword of platelet-derived extracellular vesicles in tissues, injury or repair: The current research overview

Extracellular vesicles (EVs) are vesicular bodies with a double-layered membrane structure that are detached from the cell membrane or secreted by the cells. EVs secreted by platelets account for the main part in the blood circulation, which account for about 30% or even more. Many types of cells are regulated by PEVs, including endothelial cells, leukocytes, smooth muscle cells, etc. Nevertheless, despite the growing interest in the study of extracellular vesicles, there are still only a few studies on the role of PEVs. Therefore, this overview mainly focuses on one method of isolation and the functions of PEVs in tissues found so far, including promoting tissue repair and mediating tissue damage, which can be used for researchers to continue to explore the role of PEVs in other fields.

Efficacy of intrauterine infusion therapy before embryo transfer in recurrent implantation failure: A systematic review and network meta-analysis

Previous studies of intrauterine infusion therapy in recurrent implantation failure (RIF) patients have shown conflicting results, and there is a lack of head-to-head horizontal comparisons between different drugs. This study aimed to assess the effectiveness of four intrauterine infusion drugs, including human chorionic gonadotropin (HCG), granulocyte colony-stimulating factor (G-CSF), peripheral blood mononuclear cells (PBMCs) and autologous platelet-rich plasma (PRP), in improving pregnancy outcomes in RIF patients through the network meta-analysis. Randomized controlled trials (RCTs) of preimplantation intrauterine infusion for RIF were searched in the Cochrane Library, Embase, Medline and CINAHL. Meanwhile, relevant data were extracted and Stata 15.0 software was applied to statistical analysis. A total of 21 studies with a sample size of 2917 cases were included in this study. Clinical pregnancy rate network meta-analysis showed that, intrauterine infusion of all four drugs is significantly better than the blank and placebo groups, while only PRP could significantly increase live birth rate compared with the blank and placebo groups. The SUCRA plots of clinical pregnancy and live birth rates showed a higher ranking of PRP and PBMCs. Early abortion intervention analysis found that only G-CSF is significantly better than the blank and placebo groups, and the SUCRA plot of G-CSF showed the highest ranking. All these findings confirmed that all four intrauterine infusion drugs can improve pregnancy outcomes in RIF patients to varying degrees, with PRP being the most effective. Further prospective, large-scale and high-quality RCTs are still necessary to determine the exact subgroups of benefit for the different drugs.

Evidence for Utilization of Injectable Biologic Augmentation in Primary Rotator Cuff Repair: A Systematic Review of Data From 2010 to 2022

Background

Biologic healing after rotator cuff repair remains a significant challenge. Injectable biologic augmentation may improve tissue quality at the suture-tendon interface.

Purpose

To investigate the effect of injectable biologic supplementation in rotator cuff repair and to assess the quality and adherence to evolving reporting standards.

Study Design

Systematic review; Level of evidence, 3.

Methods

A systematic review was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were 40 studies: 29 preclinical (in vivo animal models) and 11 clinical. Each clinical study was assessed for quality, risk of bias, and adherence to relevant MIBO (Minimum Information for Studies Evaluating Biologics in Orthopaedics) guidelines. The outcomes of interest were reported load to failure, load to gap, gap size, and stiffness in the preclinical studies, and healing rate and any patient-reported outcome measures in the clinical studies.

Results

Injectables reported included growth factors (eg, transforming growth factor-beta 3, erythropoietin), bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells (ADSCs), and other agents such as platelet-rich plasma (PRP) and hyaluronic acid. The most common findings for preclinical injectables were increased load to failure (16/29 studies; 55.2%) and improved collagen histological quality (11/29 studies; 37.9%). All 11 clinical studies (10 PRP, 1 ADSC) indicated no adverse events, with similar or improved patient-reported outcomes compared with repairs in the control groups. In 1 study utilizing an innovative delivery technique, a concentrated PRP globule with fibrin matrix was shuttled over a suture to maintain concentrated PRP at the repair site and demonstrated a significant decrease in retears (P = .03) at a 31-month follow-up. A matched-cohort study investigating augmentation with ADSCs demonstrated a significantly lower retear rate in the ADSC-augmented group than the control group at a 28-month follow-up (P < .001). On average, the clinical studies adhered to 66% of relevant MIBO reporting guidelines and had a low risk of bias.

Conclusion

Approximately 83% of preclinical studies found a positive biomechanical or histological effect, with no studies showing an overall negative effect. Clinically, utilization of innovative delivery techniques may reduce the risk of arthroscopic washout of PRP and improve retear rates. ADSCs were shown to reduce retear rates at a 28-month follow-up.

Potential Mechanism of Platelet-rich Plasma Treatment on Testicular Problems Related to Diabetes Mellitus

Diabetes mellitus is a condition of continuously increased blood glucose levels that causes hyperglycemia. This condition can result in disorders of various organs including testicular problems. The use of platelet-rich plasma (PRP) which is contained in several growth factors shows its potential in overcoming testicular problems. This literature review study was conducted to identify the potential of PRP in overcoming various testicular problems due to diabetic conditions.

The analgesic and anti-haemorrhagic efficacy of platelet-rich plasma in tonsillectomy: A systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

To evaluate the analgesic and anti-haemorrhagic efficacy of platelet-rich plasma (PRP) among patients undergoing tonsillectomy.

DESIGN

A systematic review and meta-analysis of randomised controlled trials (RCTs).

SETTING

PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) and Google Scholar databases were screened from inception until July 2021, and updated in December 2021.

PARTICIPANTS

Patients undergoing tonsillectomy.

MAIN OUTCOME MEASURES

The efficacy endpoints of postoperative pain and haemorrhage were summarised as standardised mean difference (SMD) and risk ratio (RR), respectively, with 95% confidence interval (CI).

RESULTS

Seven RCTs Seven RCTs were analysed, comprising a total of 392 patients. Risk of bias evaluation showed an overall high risk in one RCT, low risk in four RCTs and some concerns in two RCTs. The pooled results revealed that the mean postoperative pain score was significantly reduced in favour of the PRP group compared with the control group (SMD = -1.38, 95% CI [-1.91, -0.85], p < 0.001). Subgroup analysis showed the effect estimate was statistically significant for early postoperative pain (Day 0 to Day 3), without substantial difference between both groups on late postoperative pain (Days 5 and 7). Moreover, the rate of postoperative haemorrhage was significantly reduced in favour of the PRP group compared with the control group (RR = 0.16, 95% CI [0.05, 0.50], p = 0.001). Subgroup analysis showed the effect estimate was statistically significant for the rate of primary and secondary haemorrhage.

CONCLUSION

PRP was associated with significant reduction in postoperative pain and haemorrhage among patients undergoing tonsillectomy.

Extracellular Vesicles in Regenerative Processes Associated with Muscle Injury Recovery of Professional Athletes Undergoing Sub Maximal Strength Rehabilitation

Platelet-rich plasma (PRP) has great potential in regenerative medicine. In addition to the well-known regenerative potential of secreted growth factors, extracellular vesicles (EVs) are emerging as potential key players in the regulation of tissue repair. However, little is known about their therapeutic potential as regenerative agents. In this study, we have identified and subtyped circulating EVs (platelet-, endothelial-, and leukocyte-derived EVs) in the peripheral blood of athletes recovering from recent muscular injuries and undergoing a submaximal strength rehabilitation program. We found a significant increase in circulating platelet-derived EVs at the end of the rehabilitation program. Moreover, EVs from PRP samples were isolated by fluorescence-activated cell sorting and analyzed by label-free proteomics. The proteomic analysis of PRP-EVs revealed that 32% of the identified proteins were associated to "defense and immunity", and altogether these proteins were involved in vesicle-mediated transport (GO: 0016192; FDR = 3.132 × 10^-19), as well as in wound healing (GO: 0042060; FDR = 4.252 × 10^-13) and in the events regulating such a process (GO: 0061041; FDR = 2.812 × 10^-12). Altogether, these data suggest that platelet-derived EVs may significantly contribute to the regeneration potential of PRP preparations.

Modifying Orthobiological PRP Therapies Are Imperative for the Advancement of Treatment Outcomes in Musculoskeletal Pathologies

Autologous biological cellular preparations have materialized as a growing area of medical advancement in interventional (orthopedic) practices and surgical interventions to provide an optimal tissue healing environment, particularly in tissues where standard healing is disrupted and repair and ultimately restoration of function is at risk. These cellular therapies are often referred to as orthobiologics and are derived from patient's own tissues to prepare point of care platelet-rich plasma (PRP), bone marrow concentrate (BMC), and adipose tissue concentrate (ATC). Orthobiological preparations are biological materials comprised of a wide variety of cell populations, cytokines, growth factors, molecules, and signaling cells. They can modulate and influence many other resident cells after they have been administered in specific diseased microenvironments. Jointly, the various orthobiological cell preparations are proficient to counteract persistent inflammation, respond to catabolic reactions, and reinstate tissue homeostasis. Ultimately, precisely delivered orthobiologics with a proper dose and bioformulation will contribute to tissue repair. Progress has been made in understanding orthobiological technologies where the safety and relatively easy manipulation of orthobiological treatment tools has been demonstrated in clinical applications. Although more positive than negative patient outcome results have been registered in the literature, definitive and accepted standards to prepare specific cellular orthobiologics are still lacking. To promote significant and consistent clinical outcomes, we will present a review of methods for implementing dosing strategies, using bioformulations tailored to the pathoanatomic process of the tissue, and adopting variable preparation and injection volume policies. By optimizing the dose and specificity of orthobiologics, local cellular synergistic behavior will increase, potentially leading to better pain killing effects, effective immunomodulation, control of inflammation, and (neo) angiogenesis, ultimately contributing to functionally restored body movement patterns.

Multiple platelet-rich plasma injections are superior to single PRP injections or saline in osteoarthritis of the knee: the 2-year results of a randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

The primary purposes of this study were to prove the efficacy of PRP injection therapy on knee pain and functions by comparing patients with mild to moderate OA with a placebo control group, and also to understand the effectiveness of multiple doses compared to a single dose. It was hypothesized that PRP would lead to more favorable results than the placebo at 1, 3, 6, 12 and 24 months after treatment.

MATERIALS AND METHODS

237 patients diagnosed with OA were randomly separated into 4 groups, who were administered the following: single dose of PRP (n: 62), single dose of sodium saline (NS) (n: 59), three doses of PRP (n: 63), and three doses of NS (n: 53). Clinical evaluations were made pre-treatment and at 1, 3, 6, 12 and 24 months post-treatment, using the Knee Injury and Osteoarthritis Result Score (KOOS), Kujala Patellofemoral Score, knee joint range of motion (ROM), measurements of knee circumference (KC), and mechanical axis angle (MAA) and a Visual Analog Scale (VAS) for the evaluation of pain.

RESULTS

The better score values in the groups were recorded at 3 and 6 months. Patients treated with PRP maintained better scores at 3, 6 and 12 months compared to the NS groups (p < 0.05). Multiple doses of PRP were seen to be more effective than single-dose PRP at 6 and 12 months (p < 0.05). At the end of 24 months, there was no significant score difference across all the groups. The most positive change in scores was found in stage 2 OA, and the most positive change in ROM was in stage 3 OA patients. In the PRP groups, KC decreased more at 1 and 6 months (p < 0.05). Compared to other age groups, patients aged 51-65 years scored better at 6 months (p < 0.05). A negative correlation was determined with MAA scores (r = - 0.508, p < 0.001).

CONCLUSION

In comparison to the placebo (NS), leukocyte-rich PRP treatment was determined to be effective in the treatment of OA. Multiple doses of PRP increase the treatment efficacy and duration. Of all the patients treated with PRP, the best results were obtained by patients aged 51-65 years, with lower MAA, and by K/L stage 2 OA patients.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

REGISTRATION

NCT04454164 (ClinicalTrials.gov identifier).

Regenerative Medicine: Pharmacological Considerations and Clinical Role in Pain Management

Purpose of Review

Low back pain affects at least 80% of individuals at some point in their lifetime and is the fifth most common reason for physician visits in the USA. Treatment of an acute episode of LBP generally includes rest, activity modification, physical therapy, NSAIDs, and patient education.

Recent Findings

A small percentage of patients will develop chronic pain lasting > 6 months duration. Platelet-rich plasma (PRP) is one of the main pillars of regenerative medicine, as its release of bioactive proteins supports the aim of RM of restoring the anatomical function in degenerative conditions. Mesenchymal stem cells (MSCs) are multipotent stem cells, multipotent progenitor cells, or marrow stromal cells found in various body tissues, including bone marrow, lung, and adipose tissue. Evidence from well-designed case–control or cohort studies for the use of PRP and MSCs in lumbar facet joint, lumbar epidural, and sacroiliac joint injections is currently described as level IV evidence. PRP and MSCs are used autogenously to help facilitate the healing process, and their injection has been studied in the long-term management of discogenic low back pain. PRP has been compared to steroid injections in the sacroiliac joint for chronic low back pain, with favorable results. MSCs have also been shown to be useful in intervertebral disc regeneration and treatment of chronic low back pain associated with degenerative disc disease.

Summary

Currently, the price for these treatments is extremely high, and thus the standard of care continues to be steroid injections and other treatments. This could change, however, with more robust data and research on the safety and long-term efficacy of biologics compared to other interventional management.

The role of platelet-rich plasma in microlaryngeal surgery: a randomised, controlled trial

Objective

Platelet-rich plasma has gained interest over the two last decades, mainly because of its role in regenerative medicine. This work aimed to assess the role of intra-operative local application of platelet-rich plasma gel in the improvement of quality of voice after microlaryngeal surgery.

Method

This was a prospective comparative study that included 40 patients undergoing microlaryngeal surgery for benign vocal fold lesions. There were two groups divided equally into study group A and control group B. The assessment of voice was performed by videostroboscopy and acoustic analysis pre-operatively and at two weeks and one and three months post-operatively.

Results

The data demonstrated that all the stroboscopic and acoustic parameters showed significant improvement in both groups. Group A showed significant improvement regarding acoustic parameters at the third post-operative follow up when compared with group B.

Conclusion

Platelet-rich plasma has a beneficial effect on voice quality following microlaryngeal surgery based in particular on acoustic parameters.

Customizing the extracellular vesicles release and effect by strategizing surface functionalization of titanium

Metallic material functionalization with Extracellular Vesicles (EVs) is a desirable therapeutic approach to improve regenerative procedures. Among the different functionalization strategies available, here we have compared drop casting on machined Ti surfaces, drop casting on nanostructured TiO₂ surfaces and polymeric entrapment with polydopamine. EVs are a heterogeneous population of communication nanovesicles released by cells that are being intensively investigated for their use in therapeutics. We have selected platelet derived EVs for Ti surface coating due to their demonstrated osteoinductive properties. Our results show that each functionalization strategy leads to differences in the size of EV populations attached to and released from the metallic implants, which, in turn, leads to variations in their osteogenic capability measured through alkaline phosphatase activity and calcium deposition. In conclusion, the functionalization strategy used has an important effect on the resulting implant functionality, probably due to the heterogeneous EVs nature. Thus, the methodological approach to metallic material functionalization should be carefully chosen when working with extracellular vesicles in order to obtain the desired therapeutic application.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.

Harnessing Tissue-derived Extracellular Vesicles for Osteoarthritis Theranostics

Osteoarthritis (OA) is a prevalent chronic whole-joint disease characterized by low-grade systemic inflammation, degeneration of joint-related tissues such as articular cartilage, and alteration of bone structures that can eventually lead to disability. Emerging evidence has indicated that synovium or articular cartilage-secreted extracellular vesicles (EVs) contribute to OA pathogenesis and physiology, including transporting and enhancing the production of inflammatory mediators and cartilage degrading proteinases. Bioactive components of EVs are known to play a role in OA include microRNA, long non-coding RNA, and proteins. Thus, OA tissues-derived EVs can be used in combination with advanced nanomaterial-based biosensors for the diagnostic assessment of OA progression. Alternatively, mesenchymal stem cell- or platelet-rich plasma-derived EVs (MSC-EVs or PRP-EVs) have high therapeutic value for treating OA, such as suppressing the inflammatory immune microenvironment, which is often enriched by pro-inflammatory immune cells and cytokines that reduce chondrocytes apoptosis. Moreover, those EVs can be modified or incorporated into biomaterials for enhanced targeting and prolonged retention to treat OA effectively. In this review, we explore recently reported OA-related pathological biomarkers from OA joint tissue-derived EVs and discuss the possibility of current biosensors for detecting EVs and EV-related OA biomarkers. We summarize the applications of MSC-EVs and PRP-EVs and discuss their limitations for cartilage regeneration and alleviating OA symptoms. Additionally, we identify advanced therapeutic strategies, including engineered EVs and applying biomaterials to increase the efficacy of EV-based OA therapies. Finally, we provide our perspective on the future of EV-related diagnosis and therapeutic potential for OA treatment.

Healing of Chronic Wounds with Platelet-Derived Growth Factors from Single Donor Platelet-Rich Plasma following One Freeze-Thaw Cycle. A Cross-Sectional Study

Chronic non-healing wounds (CNHWs) may be associated with trauma or idiopathic in nature and are difficult to treat. Our objective was to assess the use of platelet-derived growth factor (PDGF) from single-donor platelets (al-PRP), using one freeze-thaw cycle, for treating CNHWs. We conducted a cross-sectional study. A total of 23 CNHWs being treated with al-PRP. The al-PRP treatment can be considered successful in well over half (n = 13, 56.5%) of the wounds. We found that all the wounds treated for up to 7 weeks showed partial or complete healing, while those treated for between 8 and 12 weeks did not show healing, healing again being successful in cases in which treatment was extended to more than 13 weeks (85.7%). Using chi-square tests, this relationship was found to be highly significant (p < 0.001, chi² = 19.51; p value = 0.00006). Notably, Cramer's V coefficient was very high (0.921), indicating that the effect size of PRP treatment duration on healing is very large (84.8%). We could suggest that the use of al-PRP in the healing of CNHWs is a promising approach. Further studies with larger sample sizes and long follow-ups are needed to obtain multivariate models to explain which factors favour the healing of ulcers treated with PRP.

Use of platelet-rich plasma in the treatment of infertility in poor responders in assisted human reproduction procedures

Couple infertility is a pathology with an absolute number of cases growing markedly over the last decade in connection mainly with the increased age of couples wishing to conceive. Platelet-rich plasma (PRP) is an alternative treatment used for several years for experimental purposes. Yet, this method is not yet defined as a standard therapeutic option in the infertility protocol for poor responders in assisted human reproduction procedures. Thus, the present study is a retrospective study conducted between February 2019 and February 2020 to evaluate the effect of ovarian PRP injection in patients with a poor ovarian response (POR) to ovarian stimulation. Women (n=20; age 31-44 years) diagnosed with POR based on the European Society of Human Reproduction and Embryology criteria underwent ovarian injection with autologous PRP injection. Markers of ovarian reserve before, during the following two menstrual cycles, and at six months after treatment were followed as well as stimulation and fertilisation parameters before and post-treatment. PRP treatment resulted in increased antral follicle count and serum anti-Mullerian hormone, while levels of serum follicle-stimulating hormone and luteinising hormone were decreased. These changes were more pronounced during the 2nd menstrual cycle following treatment. By six months following the injection, their values return to pre-treatment levels and any small differences were not considered statistically significant. The average dose of gonadotropin used and duration remained statistically unchanged, but a significant increase in estradiol achieved by the day of the human chorionic gonadotropin trigger day was achieved. The cancellation rate decreased following PRP treatment while the number of collected oocytes, number of oocytes in metaphase II rose. The number of embryos (of A and B quality) resulting also increased but fell short of the significance level set (α=0.073). Following the PRP injection, two singleton pregnancies were achieved, resulting in live births at term without complications during pregnancy. Another pregnancy was achieved spontaneously 45 months following the PRP and a failed assisted human reproduction procedure. Although the group included a small number of women, the results indicate the potential benefits of an ovarian autologous PRP injection in women with POR. Positive results appear to be short-term for 2-6 months after the procedure.

From Blood to Regenerative Tissue: How Autologous Platelet-Rich Fibrin Can Be Combined with Other Materials to Ensure Controlled Drug and Growth Factor Release

The purpose of this review is to examine the latest literature on the use of autologous platelet-rich fibrin as a drug and growth factor carrier system in maxillofacial surgery. Autologous platelet-rich fibrin (PRF) is a unique system that combines properties such as biocompatibility and biodegradability, in addition to containing growth factors and peptides that provide tissue regeneration. This opens up new horizons for the use of all beneficial ingredients in the blood sample for biomedical purposes. By itself, PRF has an unstable effect on osteogenesis: therefore, advanced approaches, including the combination of PRF with materials or drugs, are of great interest in clinics. The main advantage of drug delivery systems is that by controlling drug release, high drug concentrations locally and fewer side effects within other tissue can be achieved. This is especially important in tissues with limited blood supply, such as bone tissue compared to soft tissue. The ability of PRF to degrade naturally is considered an advantage for its use as a "warehouse" of controlled drug release systems. We are focusing on this concentrate, as it is easy to use in manipulations and can be delivered directly to the surgical site. The target audience for this review are researchers and medical doctors who are involved in the development and research of PRFs further studies. Likewise, surgeons who use PRF in their work to treat patients and who advice patients to take the medicine orally.

Exosome-Induced Vaginal Tissue Regeneration in a Porcine Mesh Exposure Model

OBJECTIVES

The purpose of this study was to explore the utility of an injectable purified exosome product derived from human apheresis blood to (1) augment surgical closure of vaginal mesh exposures, and (2) serve as a stand-alone therapy for vaginal mesh exposure.

METHODS

Sixteen polypropylene meshes (1×1-3×3 cm) were implanted in the vaginas of 7 Yorkshire-crossed pigs by urogynecologic surgeons (day 0). On day 7, group 1 underwent surgical intervention via vaginal tissue suture reclosure with (n=2 pigs, n=4 meshes) or without (n=2 pigs, n=4 meshes) exosome injection; group 2 underwent medical intervention with an exosome injection (n=3, n=8 meshes). One animal in group 2 was given oral 2'-deoxy-5-ethynyluridine to track cellular regeneration. Euthansia occurred at 5 weeks.

RESULTS

Mesh exposures treated with surgical closure alone experienced reexposure of the mesh. Exosome treatment with or without surgical closure resulted in partial to full mesh exposure resolution up to 3×3 cm. Exosome-treated tissues had significantly thicker regenerated epithelial tissue (208 μm exosomes-only and 217 μm surgery+exosomes, versus 80 μm for surgery-only; P < 0.05); evaluation of 2'-deoxy-5-ethynyluridine confirmed de novo regeneration throughout the epithelium and underlying tissues. Capillary density was significantly higher in the surgery+exosomes group (P = 0.03). Surgery-only tissues had a higher inflammatory and fibrosis response as compared with exosome-treated tissues.

CONCLUSIONS

In this pilot study, exosome treatment augmented healing in the setting of vaginal mesh exposure, reducing the incidence of mesh reexposure after suture closure and decreasing the area of mesh exposure through de novo tissue regeneration after exosome injection only. Further study of varied local tissue conditions and mesh configurations is warranted.

An In Vitro and In Vivo Comparison of Osteogenic Differentiation of Human Mesenchymal Stromal/Stem Cells

The use of stem cells in regenerative medicine, including tissue engineering and transplantation, has generated a great deal of enthusiasm. Mesenchymal stromal/stem cells (MSCs) can be isolated from various tissues, most commonly, bone marrow but more recently adipose tissue, dental pulp, and Wharton's jelly, to name a few. MSCs display varying phenotypic profiles and osteogenic differentiating capacity depending and their site of origin. MSCs have been successfully differentiated into osteoblasts both in vitro an in vivo but discrepancies exist when the two are compared: what happens in vitro does not necessarily happen in vivo, and it is therefore important to understand why these differences occur. The osteogenic process is a complex network of transcription factors, stimulators, inhibitors, proteins, etc., and in vivo experiments are helpful in evaluating the various aspects of this osteogenic process without distractions and confounding variables. With that in mind, the results of in vitro experiments need to be carefully considered and interpreted with caution as they do not perfectly replicate the conditions found within living organisms. This is where in vivo experiments help us better understand interactions that might occur in the osteogenic process that cannot be replicated in vitro. Potentially, these differences could also be exploited to develop an optimal MSC cell therapeutic product that can be used for bone disorders. There are many bone disorders, most of which cause a great deal of discomfort. Clinically acceptable protocols could be developed in which MSCs are used to aid in bone regeneration providing relief for patients with chronic pain. The aim of this review is to examine the differences between studies conducted in vitro and in vivo with regard to the osteogenic process to better define the gaps in current osteogenic research. By better understanding osteogenic differentiation, we can better define treatment strategies for various bone disorders.

Use of Autologous Leucocyte- and Platelet-Rich Plasma (L-PRP) in the Treatment of Aural Hematoma in Dogs

Leukocyte- and platelet-rich plasma (L-PRP) can accelerate the healing process by providing increased concentrations of platelet-derived growth factors. The objective of this study was to evaluate the clinical effect of L-PRP in the treatment of canine aural hematomas associated with otitis externa. Twenty mL of citrated whole blood was collected from each of the 17 dogs included and autologous L-PRP was produced. The aural hematoma was drained and 0.5–1 mL of L-PRP was injected. The dogs were examined weekly until 7 days after complete clinical healing. A final clinical follow-up was performed 6 weeks after the first treatment with L-PRP. If there was recurrence of the aural hematoma at the first follow-up, the treatment was repeated. In total, 2/17 cases were lost after the first follow-up. In 5/17 dogs, a short-term recurrence occurred. In 12/15 cases, complete clinical resolution was achieved with a single L-PRP application (Group A1) and in 3/15 with two treatments (Group A2). The mean time to complete clinical resolution was 16 ± 8.7 days (A1) and 23.3 ± 4 days (A2), respectively. No side effects were reported. The in situ administration of autologous L-PRP resulted in a complete resolution of the aural hematoma in all dogs that completed the clinical trial.

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.

Comparison of Allogeneic Platelet-rich Plasma With Autologous Platelet-rich Plasma for the Treatment of Diabetic Lower Extremity Ulcers

Autologous platelet-rich plasma (au-PRP) has been widely used for the management of refractory chronic wounds. However, patients with diabetic lower extremity ulcers (DLEUs) usually have complicated clinical conditions, and the utility of au-PRP is limited. In this study, the feasibility, effectiveness, and safety of allogeneic platelet-rich plasma (al-PRP) and au-PRP were investigated and compared in the treatment of DLEUs. A total of 75 in-patients with type 2 diabetes were assigned to the al-PRP group (n = 20), au-PRP group (n = 25), and conventional wound therapeutic (CWT) group (n = 30) matched by the ankle brachial index and ulcer size from December 2015 to August 2018. Based on metabolic and nutritional regulation, infective control, and topical wound management, al-PRP, au-PRP, and CWT were administered to each group, respectively. Evaluation of treatment outcomes was determined by the parameters of wound healing and adverse reactions. The therapeutic times and average concentration of platelets were not significantly different between the au-PRP and al-PRP groups. The wound healing times of the al-PRP group (56.9 ± 29.22 d) and au-PRP group (55.6 ± 33.8 d) were significantly shorter than those of the CWT group (88.0 ± 43.4 d) (P < 0.01), but there was no significant difference between the groups with PRP treatment. Although there was no significant difference in the daily healing area among all groups (P > 0.05), the trend of the healing rate in the al-PRP group (16.77 ± 12.85 mm²), au-PRP group (14.31 ± 18.28 mm²), and CWT group (9.90 ± 8.51 mm²) gradually decreased. No obvious adverse reactions (fever, edema, pain, skin itching, rash, or other sensory abnormalities) were observed in either the au-PRP or the al-PRP groups. Both al-PRP and au-PRP could effectively and safely promote wound healing in patients with DLEUs. Alternatively, al-PRP could be used for DLEUs as an off-the-shelf solution when au-PRP is limited.

Platelet-rich fibrin: Basics of biological actions and protocol modifications

Platelet-rich fibrin (PRF) represents second generation of platelet concentrates, which has gained increasing awareness in recent years for regenerative procedures. This biologic additive is completely autologous, easy to prepare, has minimal expense, and possesses prolonged growth factor release, together with several other advantages over traditionally prepared platelet concentrates. Since its introduction, various protocols for PRF preparation have been proposed with different amounts of growth factors and other biomolecules necessary for wound healing. However, reference data about potential effect of some PRF components on hard and soft tissue healing are still conflicting. The current article intends to clarify the relevant advances about physiological role of certain PRF components and to provide insight into the new developmental approach. Also, this review summarizes the evolution of platelet concentrates and biologic properties of different modifications of PRF procedure.

A comparative study of low-level laser efficacy on autologous activity of PRP injected in knee arthritis, in vivo study

There were many studies that attempt to measure the effect of growth factors of platelets through platelet-rich plasma (PRP) techniques on repairing of different human tissues and their efficiency either by platelets account or measuring the concentrations of growth factors secreted from platelets at various experimental conditions, to get the optimal parameters for platelets functions in healing processes. There were little trails dealing with laser and PRP for accelerating healing process that generally takes two methods, either by studding the stimulation effect of LLLT (low-level laser therapy), by subjecting laser irradiation on injured part and left for a period of time that is necessary for photobiostimulation of cell proliferations, then PRP treatment followed, or by studding the direct effects of laser on PRP factors activity. The objectives of this study are to investigate the indirect and prolonged influence of laser irradiation (650 nm with 100 mW output power) on healing processes of knee joints with induced osteoarthritis (OA), by comparison of radiated and non-radiated PRP on repairing of joint cartilage. In material and methods, we used 9 rats divided in to four groups: C1, control without any treatment, for positive comparisons of healing; C2 and C3, controls with induced OA, left for 14 days, then sacrificed for histological analysis of negative comparisons; and P and L groups that had induced with OA for 14 days and then treated with non-irradiated and radiated PRP, respectively. Preparation of PRP (condensed platelets account with high concentration of growth factors) in order to accelerate repairing processes on induced- osteoarthritis cartilage in rats groups. To estimate the efficacy of photobiostimulation or photobioinhibition on platelets' granules, we determine the absorbance of PRP by spectrophotometer. The technique was based on PRP, as a feature of platelets quantity, that compares the quality of PRP on healing of induced osteoarthritis with and without irradiation of laser, using Wistar rats as a model. The quality of platelets was measured by time required for healing according to histopathological observations and grades of OA. Finally, the results were analyzed statistically using ANOVA test (P = 0.05). Our conclusion was emphasizing the idea of inhibiting the effect of LLLT on growth factors of PRP that is responsible of speed up healing of OA.

Platelet-Rich Plasma as a Potential New Strategy in the Endometrium Treatment in Assisted Reproductive Technology

The success rate of assisted reproduction techniques (ART) has long been less than satisfactory albeit the great progress made in recent years, demonstrating the need for alternative options in the ART cycles. Growing evidence correlates the effect of intrauterine platelet-rich plasma (PRP) infusion on the endometrium with reassuring reproductive results. Thus, in this review, we focus on the current clinical and mechanical evidence on PRP and its effect on endometrial receptivity, and assess the features, benefits and limitations of the current studies and potential risks of PRP in ART.

The platelet-rich plasma and mesenchymal stem cell milieu: A review of therapeutic effects on bone healing

Platelet-rich plasma is autologous plasma that contains concentrated platelets compared to whole blood. It is relatively inexpensive to produce, can be easily isolated from whole blood, and can be administered while the patient is in the operating room. Further, because platelet-rich plasma is an autologous therapy, there is minimal risk for adverse reactions to the patient. Platelet-rich plasma has been used to promote bone regeneration due to its abundance of concentrated growth factors that are essential to wound healing. In this review, we summarize the methods for producing platelet-rich plasma and the history of its use in bone regeneration. We also summarize the growth factor profiles derived from platelet-rich plasma, with emphasis on those factors that play a direct role in promoting bone repair within the local fracture environment. In addition, we discuss the potential advantages of combining platelet-rich plasma with mesenchymal stem cells, a multipotent cell type often obtained from bone marrow or fat, to improve craniofacial and long bone regeneration. We detail what is currently known about how platelet-rich plasma influences mesenchymal stem cells in vitro, and then highlight the clinical outcomes of administering platelet-rich plasma and mesenchymal stem cells as a combination therapy to promote bone regeneration in vivo.

Characteristics of L-PRP preparations for treating Achilles tendon rupture within the PATH-2 study

Platelet-rich plasma (PRP) is an autologous preparation that has been claimed to improve healing and mechanobiological properties of tendons both in vitro and in vivo. In this sub-study from the PATH-2 (PRP in Achilles Tendon Healing-2) trial, we report the cellular and growth factor content and quality of the Leukocyte-rich PRP (L-PRP) (N = 103) prepared using a standardized commercial preparation method across 19 different UK centers. Baseline whole blood cell counts (red cells, leukocyte and platelets) demonstrated that the two groups were well-matched. L-PRP analysis gave a mean platelet count of 852.6 x 10⁹/L (SD 438.96), a mean leukocyte cell count of 15.13 x 10⁹/L (SD 10.28) and a mean red blood cell count of 0.91 x 10¹²/L (SD 1.49). The activation status of the L-PRP gave either low or high expression levels of the degranulation marker CD62p before and after ex-vivo platelet activation respectively. TGF-β, VEGF, PDGF, IGF and FGFb mean concentrations were 131.92 ng/ml, 0.98 ng/ml, 55.34 ng/ml, 78.2 ng/ml and 111.0 pg/ml respectively with expected correlations with both platelet and leukocyte counts. While PATH-2 results demonstrated that there was no evidence L-PRP is effective for improving clinical outcomes at 24 weeks after Achilles tendon rupture, our findings support that the majority of L-PRP properties were within the method specification and performance.

Efficacy and safety of platelet-rich plasma in the treatment of severe burns: A protocol for systematic review and meta analysis

BACKGROUND

In recent years, platelet-rich plasma (PRP) has been used in burn wound repair, plastic surgery, bone and tendon ligament injury repair and other treatment at home and abroad. Clinical studies indicate that PRP has a good curative effect on repairing burn wounds. The residual wounds formed after large area severe burns are difficult to cure and have recurrent attacks. Because the action mechanism of PRP is unclear, its clinical efficacy of PRP in repairing severe burn wounds is controversial. And there is no relevant systematic evaluation of PRP in repairing severe burn wounds now.

OBJECTIVE

Meta analysis was used to evaluate the efficacy and safety of PRP in repairing severe burn wounds.

METHODS

Randomized controlled clinical trial of using PRP to repair severe burn wounds were retrieved by computer WanFang, China National Knowledge Infrastructure, China Science and Technology Journal Database, China Biology Medicine disc, Embase, PubMed, Web of Science and Cochrane Library from the establishment of the database to September 2020. Two researchers independently extract data and assess the quality of the included literature, and Meta analysis of the included literature is carried out by using RevMan5.3 software.

RESULTS

In this study, the efficacy and safety of PRP in repairing severe burn wounds are evaluated from the aspects of wound healing rate, wound healing time, scar index, visual simulation score, the number of layers of dressing, the number of times of changing gauze, frequency of dressing change, the positive rate of wound bacterial culture and the incidence of inflammatory reaction.

CONCLUSIONS

PRP has a good curative effect on the repair of severe burn wounds. This study provides reliable evidence for the clinical use of PRP in the clinical repair of severe burn wounds.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/FG682.