A Novel and Convenient Method for the Preparation and Activation of PRP without Any Additives: Temperature Controlled PRP

Platelet-Rich Plasma Therapy for Rotator Cuff Injuries: A Comprehensive Review of Current Evidence and Future Directions

Rotator cuff injuries are a prevalent cause of shoulder pain and disability, significantly impacting daily activities and quality of life. Platelet-rich plasma (PRP) therapy has emerged as a potential treatment for these injuries, aiming to enhance healing by delivering concentrated platelets and growth factors. This review comprehensively evaluates the current evidence regarding PRP therapy for rotator cuff injuries. It examines clinical trial data, comparing PRP therapy with conventional treatments such as physical therapy and surgical intervention. The review also explores the biological mechanisms of PRP, including its role in promoting tendon repair and regeneration through growth factors and cytokines. In addition, it addresses variables that may affect PRP therapy outcomes, including preparation techniques, injection methods, and patient-specific factors. The review highlights the need for standardized protocols and further research to optimize PRP therapy and address existing gaps in knowledge. Future directions include exploring combined treatment approaches and assessing long-term outcomes to refine PRP therapy's role in rotator cuff injury management. This review aims to provide valuable insights into the effectiveness of PRP therapy, contributing to improved treatment strategies and enhanced patient outcomes.

The Role of Platelet-Rich Plasma in the Management of Sensorineural Hearing Loss: Current Evidence and Emerging Trends

Sensorineural hearing loss (SNHL) is a common form of hearing impairment characterized by damage to the inner ear or auditory nerve, resulting in significant communication difficulties and reduced quality of life. Current treatment options, including hearing aids, cochlear implants, and corticosteroids, primarily focus on symptom management and do not address the underlying pathophysiological damage. Platelet-rich plasma (PRP), an autologous concentrate rich in platelets and growth factors, has emerged as a potential regenerative therapy due to its ability to promote tissue repair and cellular regeneration. This review provides a comprehensive overview of the role of PRP in the management of SNHL, examining the current evidence from preclinical and clinical studies. We discuss the mechanisms through which PRP may promote auditory tissue regeneration and repair, analyze its efficacy and safety profile, and explore innovative approaches and future directions in its application for SNHL. Despite promising preliminary findings, further research is needed to optimize PRP protocols, establish standardized treatment guidelines, and conduct large-scale randomized controlled trials to validate efficacy. This review aims to highlight the potential of PRP as a novel therapeutic strategy in treating SNHL and its possible integration into current clinical practices, offering new hope for patients with this debilitating condition.

CCL28 modulates neutrophil responses during infection with mucosal pathogens

The chemokine CCL28 is highly expressed in mucosal tissues, but its role during infection is not well understood. Here, we show that CCL28 promotes neutrophil accumulation in the gut of mice infected with Salmonella and in the lung of mice infected with Acinetobacter. Neutrophils isolated from the infected mucosa expressed the CCL28 receptors CCR3 and, to a lesser extent, CCR10, on their surface. The functional consequences of CCL28 deficiency varied between the two infections: Ccl28-/- mice were highly susceptible to Salmonella gut infection but highly resistant to otherwise lethal Acinetobacter lung infection. In vitro, unstimulated neutrophils harbored pre-formed intracellular CCR3 that was rapidly mobilized to the cell surface following phagocytosis or inflammatory stimuli. Moreover, CCL28 stimulation enhanced neutrophil antimicrobial activity, production of reactive oxygen species, and formation of extracellular traps, all processes largely dependent on CCR3. Consistent with the different outcomes in the two infection models, neutrophil stimulation with CCL28 boosted the killing of Salmonella but not Acinetobacter. CCL28 thus plays a critical role in the immune response to mucosal pathogens by increasing neutrophil accumulation and activation, which can enhance pathogen clearance but also exacerbate disease depending on the mucosal site and the infectious agent.

Exploring Platelet-Rich Plasma Therapy for Knee Osteoarthritis: An In-Depth Analysis

The use of platelet-rich plasma (PRP) in all medical fields is currently gaining popularity (1). PRP is a biological product that can be defined as a segment of the plasma fraction of autologous blood with a platelet concentration level above the baseline (2). The fact that it has uses in tissue regeneration and wound healing has caught the eye of orthopedic surgeons as well, as intra-articular treatments have continued to evolve. Its benefits in the treatment of different osteoarticular pathologies are of great interest in the evolving orthopedic community, targeting mostly knee osteoarthritis, meniscus and ligament injuries (3). The purpose of this review is to update the reader on the current uses of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis pathology and to provide clinical feedback on its uses in the fields of orthopedic and sports medicine practice (4). We proceeded in studying 180 titles and abstracts eligible for inclusion. Compared to alternative treatments, PRP injections greatly improve the function of the knee joint.

Photothermal Biostimulation of Platelet-Rich Plasma Improves Hand Rejuvenation Clinical Outcome: A Pilot Study

Objective: This study aimed to evaluate physical skin changes and patients' subjective perception of treatment with photothermal bioactivated platelet-rich plasma (MCT Plasma) for hand rejuvenation. Background: Age-related changes in the dorsum of the hand include volume loss, dyschromia, and soft-tissue atrophy, which result in wrinkles and prominent deep structures. Methods: We conducted a prospective, single-center, randomized pilot study on 10 healthy female volunteers from 30 to 65 years with hand aging signs. Patients received two sessions of MCT Plasma on the treated hand and two sessions of standard platelet-rich plasma (PRP) on the control hand. Results were assessed through high-frequency ultrasonography, photographs, a patient satisfaction survey, patient perception of skin aspect, and patient perception of amelioration survey. Results: Ten women with a mean age of 57.5 years (standard deviation 10.5, range 31 - 67) were included, and seven (70%) completed the study. The treated hands' skin subepidermal low-echogenic band (SLEB) decreased from 20% to 60%, and 57.1% (n = 4) had better results than control. Twenty percent of patients were very satisfied with the results, 40% were satisfied, 40% were neutral, and none were unsatisfied or very unsatisfied. Patients perceived the skin of the treated hand (MCT Plasma) as "much better" (20%), "better" (60%), and "no changes" (20%) compared with the skin of the control hand (standard PRP). No treatment-related adverse events were reported during the study. Conclusions: Hands treated with MCT Plasma tended to have better outcomes in reducing SLEB compared with those treated with standard PRP. Patients were satisfied and the treatment was safe with no technical complications. However, further randomized controlled trials with larger sample sizes are mandatory to validate the extent of improvement provided by this device based on photothermal biomodulation.

Challenges in Application: Gelation Strategies of DAT-Based Hydrogel Scaffolds

Decellularized adipose tissue (DAT) has great clinical applicability, owing to its abundant source material, natural extracellular matrix microenvironment, and nonimmunogenic attributes, rendering it a versatile resource in the realm of tissue engineering. However, practical implementations are confronted with multifarious limitations. Among these, the selection of an appropriate gelation strategy serves as the foundation for adapting to diverse clinical contexts. The cross-linking strategies under varying physical or chemical conditions exert profound influences on the ultimate morphology and therapeutic efficacy of DAT. This review sums up the processes of DAT decellularization and subsequent gelation, with a specific emphasis on the diverse gelation strategies employed in recent experimental applications of DAT. The review expounds upon methodologies, underlying principles, and clinical implications of different gelation strategies, aiming to offer insights and inspiration for the application of DAT in tissue engineering and advance research for tissue engineering scaffold development.

Inadequate anticoagulation and hyperuricemia cause knee pain after platelet-rich plasma injection: A retrospective study

OBJECTIVES

Platelet-rich plasma treatment delays the need for total knee replacement in patients with knee osteoarthritis. However, its use and preparation remain controversial. The aim of this study was to investigate the relationship between anticoagulant use in the preparation of platelet-rich plasma and post-treatment pain in patients with knee osteoarthritis. Additionally, we explored the efficacy of platelet-rich plasma over medium- and long-term follow-up periods and identified other factors that may affect treatment outcomes.

METHODS

In this retrospective study, 225 patients with knee osteoarthritis, who underwent knee platelet-rich plasma treatment from June 2021 to January 2022, were examined at three study centres. Patients were categorised, based on the type and amount of anticoagulant used during platelet-rich plasma preparation, into 4% sodium citrate (SC) 0.6 mL, 4% SC 1 mL, 4% SC 2 mL, heparin 0.1 mL, and heparin 0.2 mL groups. We analysed the patients' basic information, pain after treatment, and inflammatory markers (i.e., interleukin 6, tumour necrosis factor-α, and hypersensitive C-reactive protein) in the joint fluid via enzyme-linked immunosorbent assay and joint fluid crystallisation. Additionally, we assessed the patients' Western Ontario and McMaster University scores and minimal clinically significant differences after treatment.

RESULTS

Patients in the 4% SC 0.6 mL and heparin 0.1 mL groups experienced less pain after platelet-rich plasma treatment than did patients in the high-dose anticoagulant group. The joint fluid of patients with pain in these groups had lower levels of inflammatory markers. Patients treated with SC had slightly better medium- and long-term therapeutic outcomes than did patients treated with heparin. Patients with poorly controlled hyperuricemia also experienced pain after platelet-rich plasma treatment.

CONCLUSIONS

The results suggest that platelet-rich plasma prepared using high-dose anticoagulants or administered to patients with poorly controlled hyperuricaemia may lead to moderate-to-severe knee pain and joint effusion after joint puncture therapy. Platelet-rich plasma had a therapeutic effect on knee osteoarthritis; however, its efficacy gradually decreased over time. SC anticoagulant is more suitable for platelet-rich plasma preparation than is heparin. Further studies are needed to understand the safety and the various factors influencing platelet-rich plasma therapy.

Cord blood platelet rich plasma (PRP) as a potential alternative to autologous PRP for allogenic preparation and regenerative applications

As an abundant supplier of growth factors, chemokines and other bioactive molecules, platelet rich plasma (PRP) become a leading therapy for tissue regeneration. The PRP therapy is an inexpensive and feasible source of growth factor compared to commercial products however, the better source of platelets is the major challenge. Many researchers are skeptical about cord blood as an alternative source for the allogenic preparation of PRP. In the present study, we have compared adult peripheral and cord blood PRP for their regenerative capacity and immuno-modulatory nature. ELISA data indicates that the cord PRP contained a considerably higher amount of growth factors compared to adult PRP. In-vitro results indicate a significant increase in cell proliferation and migration with cord PRP treatment. The immunomodulatory evaluation shows cord blood PRP has better potential in switching activated macrophages to anti-inflammatory markers when compared with adult PRP, as well as the cytokines production indicates a significant reduction in the release of IFN-γ in cord PRP treatment. The study shows the beneficial effects of using cord blood PRP over adult PRP however, future studies are required to validate cord blood PRP as a permanent source for regenerative therapy.

Comparison of the Efficacy Between Regional Nerve Block and Ring Block as Local Anesthetic Techniques for Platelet-Rich Plasma Treatment

Introduction Platelet-rich plasma (PRP), a solution of concentrated platelets, has been widely used to promote wound repair and tissue regeneration. In the treatment of pattern hair loss, platelets in PRP secrete an abundance of growth factors, including platelet-derived growth factor (PDGF), fibroblast growth factor(FGF), and many more, which stimulate and increase signaling molecules and accelerate cell proliferation. In the PRP treatment for hair regrowth, the supratrochlear nerve (STN) block and supraorbital nerve (SON) block are given to anesthetize the scalp up to the vertex except for the temporal region. The ring block is the common local anesthetic technique used by infiltrating local anesthetic agents around the target area. The primary objectives were to compare the pain and anesthetic success rates produced by regional nerve blocks and ring blocks. Materials and methods A sample size of 100 patients undergoing PRP treatment for hair regrowth were taken as the subjects for the study. Patients were allotted into two groups by randomization. Group 1 was given regional nerve blocks as the anesthetic technique used for local anesthesia, and group 2 was given ring blocks. In the study group, STN and SON blocks as the regional nerve blocks were given 2% lignocaine with 1:80000 adrenaline to anesthetize the area, and the PRP was injected from the anterior hairline up to the vertex of the scalp, not involving the occipital and temporal regions. In the control group, a ring block was given for the same procedure. Participants from both groups were assessed for the pain and analgesia caused by ring block and regional nerve blocks using the visual analog scale (VAS). Results A mean rank of 30.28 was observed for the regional nerve block technique, and a mean rank of 70.72 was observed for the ring block technique. A p-value of 0.00 that is <0.05 was observed, which shows there is a significant difference in the pain and the analgesia experienced by the subjects between the two groups, during and three hours after the procedure. Conclusion PRP is one of the most commonly used treatments for hair regrowth. The ring block is the common local anesthetic technique used for producing anesthesia, while regional nerve blocks are more effective in producing local anesthesia. This study proves that STN and SON blocks are better anesthetic techniques than the ring block technique for PRP treatment in hair growth.

Optimizing Platelet-Rich Plasma: Spin Time and Sample Source

The buff-colored layer separating the plasma from red blood cells (RBCs) in centrifuged blood was named the "buffy coat" in the late 19th century. The division of platelets (PLTs) and leukocytes (WBCs) between the buffy coat, plasma, and RBC layers in centrifuged blood has not been described before. In this study, we centrifuged 8.5 mL anticoagulated blood samples at 1000× g for 1, 2, 3, 5, 10, and 20 min. We then divided each sample into ten layers and analyzed each layer for cellular composition and mean platelet volume (MPV). Our results show that even after 20 min of centrifugation, about 15% of platelets remain in the plasma layers and 65% in the RBC layers. We found that the platelet count achieved from aspiration of 1 mL volume was optimal, with aspiration beginning 1/2 mL below the buffy coat and extending 1/2 mL above the buffy coat rather than beginning at the buffy coat itself and aspirating only plasma. Using this method of aspiration, we found that the total platelet count means reached a maximum in the 1 mL around the buffy coat after only 5 min of centrifugation.

Biotherapeutic Applications of Platelet-Rich Plasma in Regenerative Medicine

BACKGROUND

Platelet-rich plasma (PRP), a blood-based product containing platelets and growth factors, is being utilized to treat numerous non-hemostatic disorders. Studies have explored the use of PRP to provide rapid repair, healing, and recovery from various injuries; some studies mentioned the effectiveness of PRP as compared with other forms of treatment like the use of hyaluronic acid. Commercially available PRP systems are available now, and each varies from one another depending on how it is prepared, thus causing variations in platelet concentration and growth factor content. These variations also implicated different therapeutic applications.

METHODS

The paper reviews the various applications of PRP, including factors to consider before using PRP therapy, and provides an extensive list of PRP applications.

RESULTS

The administration of PRP as a standalone treatment or as a co-therapy results in observed positive outcomes. However, there is a lack of standardization for PRP preparation, increasing the risks for heterogeneity and bias amongst results.

CONCLUSION

The use of PRP is indeed an option for regenerative therapy, but more research is needed before it can fully be recommended as a primary treatment modality.

Autologous i-PRF promotes healing of radiation-induced skin injury

Skin, as an exposed tissue, often suffers damage after exposure to radiotherapy and accidental events, which may lead to the formation of chronic refractory wounds. However, effective treatment options are usually limited for severe radiation-induced skin injury (RSI). Platelet-rich plasma (PRP) has been identified to promote wound healing, but whether a new generation of blood-derived biomaterial, injectable platelet-rich fibrin (i-PRF), is effective in repairing RSI remains unclear. In this study, blood was drawn from humans and Sprague-Dawley rats to prepare PRP and i-PRF, and the regenerative functions of PRP and i-PRF were investigated by exposing the dorsal skin of SD rats to local radiation (45 Gy) and exposing HDF-α cells and human umbilical vein endothelial cells (HUVECs) cells to X-rays (10 Gy). The healing effect of i-PRF on RSI was analysed by tube formation assay, cell migration and apoptosis assays, ROS assay, wound healing assay, histological characterisation and immunostaining. The results showed that exposure to high doses of radiation reduced cell viability, increased ROS levels and induced cell apoptosis, thereby causing dorsal trauma of rats. However, both PRP and i-PRF could resisted RSI, and they were capable of reducing inflammation and promoting angiogenesis and vascular regeneration. i-PRF has a higher concentration of platelets and platelet-derived growth factors, which has a more convenient preparation method and better repair effect and possesses a good application prospect for the repair of RSI.

Efficacy of photo-thermal-bioactivated platelet-rich plasma for skin biostimulation in patients not eligible for other medical-aesthetic treatment: A pilot study

PURPOSE

To evaluate the efficacy and safety of photothermal bioactivated platelet-rich plasma for reducing laxity in facial rejuvenation in patients not eligible for other aesthetic treatments due to several comorbidities.

METHODS

A prospective, nonrandomized study was conducted. Efficacy was assessed through a satisfaction scale and the Facial Laxity Rating Scale. Safety assessments were based on the data of all adverse events and the visual analog pain scale.

RESULTS

Seven patients with a mean age of 51 (standard deviation [SD] 7.46, range 42-63) were included. In six patients (85.7%), the treatment was applied to the face and neck, and in one patient (14.3%), only to the lower half of the face and neck. The physician's perception of laxity decreased, and the procedure was not complex. Patients' and physician satisfaction increased as the study progressed. Adverse effects were not serious and resolved without sequelae. The patients' pain perceived during the treatment was mild in most cases.

CONCLUSION

The photothermal bioactivated platelet-rich plasma injections were a safe and effective treatment for facial laxity in patients not eligible for other procedures, providing good satisfaction.

Platelet-rich plasma injection for the treatment of ankle osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Platelet-rich plasma (PRP) injection for ankle osteoarthritis (OA) treatment showed contradictory results. This review was aimed to pool individual studies which assessed the efficacy of PRP for ankle OA treatment.

METHODS

This study was conducted following the preferred report items of systematic review and meta-analysis guideline. PubMed and Scopus were searched up to January 2023. Meta-analysis, or individual randomised controlled trial (RCT), or observational studies were included if they involved ankle OA with aged ≥ 18 years, compared before-after receiving PRP, or PRP with other treatments, and reported visual analog scale (VAS) or functional outcomes. Selection of eligible studies and data extraction were independently performed by two authors. Heterogeneity test using Cochrane Q test and the I²-statistic were assessed. Standardised (SMD) or unstandardised mean difference (USMD) and 95% confidence interval (CI) were estimated and pooled across studies.

RESULTS

Three studies from meta-analysis and two individual studies were included, which consisted of one RCT and four before-after studies with 184 ankle OAs and 132 PRP. The average age was 50.8-59.3 years, and 25-60% of PRP injected cases were male. The number of primary ankle OA was accounted to 0-100%. When compared to before treatment, PRP significantly reduced VAS and functional score at 12 weeks with pooled USMD of - 2.80, 95% CI - 3.91, - 2.68; p < 0.001 (Q = 82.91, p < 0.001; I² 96.38%), and pooled SMD of 1.73, 95% CI 1.37, 2.09; p < 0.001 (Q = 4.87, p = 0.18; I² 38.44%), respectively.

CONCLUSION

PRP may beneficially improve pain and functional scores for ankle OA in a short-term period. Its magnitude of improvement seems to be similar to placebo effects from the previous RCT. A large-scale RCT with proper whole blood and PRP preparation processes is required to prove treatment effects. Trial registration PROSPERO number CRD42022297503.

Efficacy of Platelet-Rich Plasma Injection in the Management of Rotator Cuff Tendinopathy: A Review of the Current Literature

Platelet-rich plasma (PRP) is being projected as a newer and superior treatment option for rotator cuff tendinopathy. With the first use of PRP in trauma and orthopedics dating back only to 1998, its advent into the field is relatively recent. Thus, data on long-term efficacy, large cohort studies, or large randomized controlled trials are fairly limited. Moreover, owing to the absence of standardized methods of platelet extraction and lack of consensus on the ideal concentration of platelets in PRP, data comparison from different studies is difficult. Things are complicated by the fact that it is also not clear whether a single injection of PRP is therapeutic or if multiple serial injections are needed to produce the desired effects. The literature on efficacy and pain relief is also obtained from studies with low sample sizes and short follow-ups. The dropout rate and noncompliance rate were also found to be high in some studies. Thus, the data is often not clinically significant and may also be biased due to the non-standardized inclusion and exclusion criteria of the studies. Though multiple studies have suggested good pain control with PRP injection, many studies have found that PRP injection therapy may not be any better than the physical therapy regimen prescribed to patients with rotator cuff tendinopathy. Also, the data on the efficacy of PRP on shoulder function and shoulder range of motion is at variance. This submission aims to evaluate the efficacy and use of PRP in the management of rotator cuff tendinopathy.

Evaluation of the Effects of Platelet-Rich Plasma on Follicular and Endometrial Growth: A Literature Review

Platelet-rich plasma (PRP) has been used in several areas of medicine due to its ability to promote tissue regeneration by growth factors and cytokines. This review addresses the use of PRP to rejuvenate ovarian follicles and increase the thickness of the endometrium to receive an embryo. PRP is obtained from the patient's own blood (autologous blood) - a fact that determines a lower chance of rejection reactions. Alpha granules of platelets provide and release supra physiological amounts of growth factors and cytokines, which provide a regenerative stimulus in tissues with low healing potential. In the ovary, PRP and its growth factors stimulate vascularization and recruitment of available primordial follicles that could no longer be otherwise stimulated. The rejuvenation of the ovary by PRP infusion aims to obtain new oocytes in ovaries with low numbers of follicles or low follicular reserve markers. In the preparation of the endometrium, PRP is used for its several growth factors that allow tissue proliferation and endometrial thickening, especially in cases of endometria that are difficult to prepare or that fail to reach an adequate minimum thickness (>7mm). To date, there are few studies of greater expression in the literature that support the use of PRP with the two purposes described above. Thus, although promising, the technique must still be validated by larger clinical trials.

Materials Selection for the Injection into Vaginal Wall for Treatment of Vaginal Atrophy

Vaginal atrophy caused by the aging process and perineal trauma has a negative impact on women. A new vaginal atrophy treatment is injection of materials into the vaginal wall, including platelet-rich plasma (PRP), autogenous fat graft (AFG), hyaluronic acid (HA), botulinum toxin (BTX), and collagen, but to date their efficacy has not been reviewed. Vaginal wall injection is available only for mild cases of vaginal atrophy or as an adjunct to vaginal surgery. PRP is used mainly to restore vaginal function, and multiple injections are needed to achieve good results in vaginal atrophy. HA, AFG, and collagen are used mainly to augment the vaginal wall. BTX injection can inhibit vaginal muscle spasm and reduce pain during sexual intercourse in patients with vaginismus. Injection of most of these materials into vaginal wall is effective and relatively safe. Vascular embolisms are the most serious complication of vaginal injection and should be prevented. In addition, there has been no randomized double-blind placebo-controlled trial or discussion of methods to avoid serious complications resulting from vaginal injection. Therefore, further studies of the injection of materials into the vaginal wall to treat vaginal atrophy are required, and the procedures should be standardized to benefit more patients.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Botulinum toxin and platelet rich plasma as innovative therapeutic modalities for keloids

Keloids characterize a definitely challenging type of cutaneous scars for which a diversity of therapeutic modalities has been suggested. The aim of this work was to compare the therapeutic efficacy of intralesional injection of botulinum toxin type-A (BTX-A), platelet rich plasma (PRP), and triamcinolone acetonide (TAC) in keloids. A total of 60 keloids patients were enrolled and divided randomly into three equal groups. Group I treated by intralesional BTX-A injection, group II treated by intralesional PRP injection, and group III treated by intralesional TAC injection. Clinical assessment was done by Vancouver Scar Scale (VSS), Verbal Rating Scale (VRS), and dermoscopic examination. Additionally, histopathology and immunohistochemistry of connective tissue growth factor (CTGF) expression were evaluated. The results of this study revealed significant improvement of both VSS and VRS in response to all treatment modalities. There was significant improvement of VSS in BTX-A and PRP groups more than TAC group. However, no significant difference observed between BTX-A and PRP groups. Immunohistochemical examination showed significant decrease of CTGF expression after treatment in BTX-A and PRP groups more than TAC group. In conclusion, both BTX-A and PRP could yield a chance for cosmetically better outcomes in keloids treatment than conventional TAC injection.

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

BACKGROUND

Platelet-rich plasma (PRP) and its derivatives are an emerging biotechnology whereby concentrated platelets provide damaged tissue with growth factors, cytokines, and other mediators to improve healing outcomes. Although there is strong evidence in the benefits of autologous PRP for both acute and chronic wounds, allogeneic PRP has been studied far less in comparison.

SUMMARY

In this mini-review, we discuss critical steps of allogenic PRP (and its derivatives) preparation. We performed a non-systematic review of the literature to identify animal and human subject studies testing allogenic PRP for wound treatment. We searched OVID Medline and PubMed for articles using the keywords "wound, ulcer, lesion, skin, and cutaneous" and "PRP, or platelet-rich plasma, or platelet-rich fibrin, or PRF, or platelet releasate" and "homologous, allogeneic or allogenic," which were limited to non-review articles and English language. Two studies in animal models and 8 studies in patients were reviewed. There were inconsistencies in preparation methods, treatment regimens, and some lacked a control group in their studies. Despite these variations, none of the studies identified any major side effects or adverse events. The treatment resulted in a reduced time to heal and/or reduced wound size in most cases. Key Messages: In situations where autologous PRP is not available or suitable, allogeneic PRP appears to provide a safe alternative. Its efficacy, however, requires larger-scale studies with appropriate controls. Standardization in PRP preparation and treatment regime are also needed to be able to interpret allogenic PRP efficacy.

Technical Procedures for Preparation and Administration of Platelet-Rich Plasma and Related Products: A Scoping Review

Introduction

Platelet-rich plasma is widely used for different types of clinical situations, but universal standardization of procedures for its preparation is still lacking.

Methods

Scoping review of comparative studies that have assessed at least two alternatives in one or more stages of preparation, storage and/or administration of PRP or its related products. A systematic search was conducted in MEDLINE, Embase, and LILACS. Two authors screened references independently. Data extraction was performed iteratively, and results were presented for each included comparison.

Results

Thirty-nine studies were included after assessing full texts, focusing on the comparison of PRP to a related product, types of anticoagulants, centrifugation protocols, commercial kits, processing time, methods for activation, and application concomitantly to other substances. Only laboratory outcomes were assessed, as platelet, leukocyte and growth factor concentrations.

Conclusion

Results showed great variability related to methods employed in different stages of PRP processing, which may explain the variability observed in clinical trials assessing the efficacy of PRP for different clinical situations.

PRP in wound healing applications

Platelets play a crucial role in hemostasis, tissue regeneration and host defense. Based on these settings, platelet-rich plasma (PRP) and its derivatives are therapeutically used to promote wound healing in several scenarios. This review summarizes the biological mechanisms underlying the most traditional as well as innovative applications of PRP in wound healing. These mechanisms involve the combined action of platelet-derived growth factors and cytokines, together with the role of plasma-derived fibrillar, antioxidant and homeostatic factors. In addition, regenerative treatments with PRP consist of personalized and non-standardized methods. Thus, the quality of PRP varies depending on endogenous factors (e.g., age; gender; concomitant medication; disease-associated systemic factors; nutrition) and exogenous factors (anticoagulants and cellular composition). This review also analyses whether these factors affect the biological mechanisms of PRP in wound healing applications.

[Optimized preparation method of leukocytes-rich platelet-rich plasma by varying conditions during centrifugation]

OBJECTIVE

To identify a more popularized preparation protocol of leukocytes-rich platelet-rich plasma (L-PRP) for higher tolerance rate.

METHODS

The peripheral blood samples of 76 volunteers (45.0 mL/case) were mixed with 5 mL sodium citrate injection for blood transfusion, and L-PRP was prepared by twice centrifugations. All blood samples were divided into three groups according to the parameters of twice centrifugation: experimental group A (12 cases, 400× g, 10 minutes for the first time and 1 100× g, 10 minutes for the second time), experimental group B (27 cases, 800× g, 10 minutes for the first time and 1 100× g, 10 minutes for the second time), and control group (37 cases, 1 360× g, 10 minutes for the first time and 1 360× g, 10 minutes for the second time). The platelet recovery rate and platelet and leukocyte enrichment coefficient of L-PRP in each group were calculated and compared.

RESULTS

After removal of abnormal blood samples (platelet recovery rate was more than 100% or white thrombus), the remaining 55 cases were included in the statistical analysis, including 10 cases in experimental group A, 21 cases in experimental group B, and 24 cases in control group. The platelet enrichment coefficient and platelet recovery rate of experimental group B were significantly higher than those of experimental group A and control group ( P<0.05); there was no significant difference between experimental group A and control group ( P>0.05). There was no significant difference in leukocyte enrichment coefficient between experimental groups A, B, and control group ( P>0.05).

CONCLUSION

The preparation quality of PRP is affected by various factors, including centrifugal force, centrifugal time, temperature, and operation process, etc. Twice centrifugation (800× g, 10 minutes for the first time and 1 100× g, 10 minutes for the second time) is an ideal and feasible centrifugation scheme, which can obtain satisfactory platelet recovery rate and enrichment coefficient with thicker buffy coat, which can reduce the fine operation requirements for operators, improve the fault tolerance rate and generalization.

Anticoagulants Interfere With the Angiogenic and Regenerative Responses Mediated by Platelets

Background and aims

Platelet rich plasma (PRP) obtained from blood anticoagulated with acid-citrate-dextrose (ACD) or sodium-citrate (SC) is used for regenerative medicine as source of platelet-derived growth factors. Allergic reactions against citrate were reported in patients after local injection of PRP allowing us to hypothesize that anticoagulants exert a harmful and local effect that interferes with the regenerative proprieties of platelets. Herein we test this hypothesis by analyzing the effect of ACD and SC on angiogenic and regenerative responses mediated by platelets.

Methods

PRP was obtained from SC- or ACD-anticoagulated blood; platelets were lysed to release growth factors; and PRP releasates (PRPr) were used to induce in vitro endothelial proliferation and 2D-migration, and regeneration of mouse skin wounds.

Results

We first compared proliferation and migration of endothelial cells mediated by anticoagulated-PRPr supplemented or not with CaCl₂. Alteration of endothelial adhesion and impediment of proliferation and migration was observed without CaCl₂. Although endothelial morphology was normalized in SC- and ACD-PRPr after calcium restitution, angiogenic responses were only markedly induced by SC-PRPr. In vivo studies revealed a delay in mouse skin regeneration after treatment with anticoagulated-PRPr without CaCl₂. Healing was only induced after calcium restitution in SC- but ACD-PRPr. Moreover, the development of inflammatory intradermal papules was evidenced after injection of ACD-PRPr. Supplementation of SC-PRPr with the equivalent concentration of dextrose (D-Glucose, 18 mM) present in ACD-PRPr resulted in reduction of endothelial proliferation and migration, delay of mouse skin regeneration and development of intradermal papules. Finally, collecting blood with half amount of SC significantly improved all the angiogenic and regenerative responses mediated by PRPr. In contrast, the delay of skin regeneration and the development of inflammatory papules remained stable after dilution of ACD.

Conclusion

Our findings indicate that (1) calcium restitution is required to impair the cellular and tissue alterations induced by citrated-anticoagulants contained in PRP; (2) ACD-derived dextrose confers anti-angiogenic, anti-regenerative and pro-inflammatory proprieties to PRP; and (3) half concentration of SC improves the angiogenesis and regeneration mediated by PRP.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.