Platelet rich plasma in oral and maxillofacial surgery from the perspective of composition

Systematic Review of Platelet-Rich Plasma in Medical and Surgical Specialties: Quality, Evaluation, Evidence, and Enforcement

Background: Platelet-rich plasma (PRP) is widely used in various medical and surgical specialties for its regenerative properties, including aesthetics (facial rejuvenation, hair restoration, and skin tightening) and orthopedics (treatment of tendinitis and osteoarthritis). However, the inconsistent literature on PRP's efficacy and safety leads to critical knowledge gaps. This systematic review evaluates quality control measures in PRP preparation and application and explores the regulatory environment governing its clinical use. Methods: Following PRISMA guidelines, a comprehensive search was conducted across multiple databases, including PubMed, EMBASE, and Web of Science, for studies published from January 2020 to April 2024. The review included randomized controlled trials (RCTs) involving human participants undergoing PRP treatment for aesthetic or regenerative purposes. Key parameters such as the PRP preparation methods, platelet concentration, and quality control measures were analyzed. The study protocol was registered with PROSPERO (ID: CRD42024557669). Results: Out of 75 RCTs involving 5726 patients, the review identified significant variability in PRP preparation methods and application techniques, including differences in centrifugation protocols and platelet concentration levels. A new evidence-based scoring system, the William-Eqram Scoring System for PRP Quality Reporting (WESS-PQR), was proposed to address these inconsistencies. Correlation analysis revealed a strong positive correlation (r = 0.79) between proper temperature control during preparation and PRP efficacy. Initial platelet count assessment showed a moderate positive correlation (r = 0.57) with efficacy. Conclusions: Standardized PRP preparation protocols and robust regulatory frameworks are urgently needed to ensure the safety and efficacy of PRP treatments. The proposed WESS-PQR scoring system can serve as a valuable tool for clinicians and researchers, promoting consistency and reliability in PRP applications.

Arthroscopic management and recent advancements in the treatment of temporomandibular joint disorders

In oral and maxillofacial surgery, the evolution of minimally invasive techniques has revolutionised the management of temporomandibular joint (TMJ) disorders. At the forefront of this advancement lies TMJ arthroscopy, a procedure that offers a precise approach to diagnosing and treating joint issues. TMJ arthroscopy is indicated in various clinical scenarios where a detailed evaluation and targeted interventions within the TMJ are required to alleviate symptoms, improve joint function, and enhance the overall quality of life of patients suffering from TMJ disorders.

Plasma Rich in Growth Factors in Bone Regeneration: The Proximity to the Clot as a Differential Factor in Osteoblast Cell Behaviour

The osteogenic differentiation process, by which bone marrow mesenchymal stem cells and osteoprogenitors transform into osteoblasts, is regulated by several growth factors, cytokines, and hormones. Plasma Rich in Growth Factors (PRGF) is a blood-derived preparation consisting of a plethora of bioactive molecules, also susceptible to containing epigenetic factors such as ncRNAs and EVs, that stimulates tissue regeneration. The aim of this study was to investigate the effect of the PRGF clot formulation on osteogenic differentiation. Firstly, osteoblast cells were isolated and characterised. The proliferation of bone cells cultured onto PRGF clots or treated with PRGF supernatant was determined. Moreover, the gene expression of Runx2 (ID: 860), SP7 (ID: 121340), and ALPL (ID: 249) was analysed by one-step real-time quantitative polymerase chain reaction (RT-qPCR). Additionally, alkaline phosphatase (ALPL) activity determination was performed. The highest proliferative effect was achieved by the PRGF supernatant in all the study periods analysed. Concerning gene expression, the logRGE of Runx2 increased significantly in osteoblasts cultured with PRGF formulations compared with the control group, while that of SP7 increased significantly in osteoblasts grown on the PRGF clots. On the other hand, despite the fact that the PRGF supernatant induced ALPL up-regulation, significantly higher enzyme activity was detected for the PRGF clots in comparison with the supernatant formulation. According to our results, contact with the PRGF clot could promote a more advanced phase in the osteogenic process, associated to higher levels of ALPL activity. Furthermore, the PRGF clot releasate stimulated a higher proliferation rate in addition to reduced SP7 expression in the cells located at a distant ubication, leading to a less mature osteoblast stage. Thus, the spatial relationship between the PRGF clot and the osteoprogenitors cells could be a factor that influences regenerative outcomes.

How to explain the beneficial effects of platelet-rich plasma

Platelet-rich plasma (PRP) is the platelet and leukocyte-containing plasmatic fraction of anticoagulated autologous blood. While evidence supporting the clinical use of PRP in dentistry is low, PRP is widely used in sports medicine, orthopedics, and dermatology. Its beneficial activity is commonly attributed to the growth factors released from platelets accumulating in PRP; however, evidence is indirect and not comprehensive. There is thus a demand to revisit PRP with respect to basic and translational science. This review is to (i) recapitulate protocols and tools to prepare PRP; (ii) to discuss the cellular and molecular composition of PRP with a focus on platelets, leukocytes, and the fibrin-rich extracellular matrix of coagulated plasma; and finally (iii) to discuss potential beneficial effects of PRP on a cellular and molecular level with an outlook on its current use in dentistry and other medical fields.

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.

Biochemical and biomechanical characterization of an autologous protein-based fibrin sealant for regenerative medicine

Accidental events or surgical procedures usually lead to tissue injury. Fibrin sealants have proven to optimize the healing process but have some drawbacks due to their allogeneic nature. Autologous fibrin sealants present several advantages. The aim of this study is to evaluate the performance of a new autologous fibrin sealant based on Endoret®PRGF® technology (E-sealant). One of the most widely used commercial fibrin sealants (Tisseel®) was included as comparative Control. E-sealant´s hematological and biological properties were characterized. The coagulation kinetics and the microstructure were compared. Their rheological profile and biomechanical behavior were also recorded. Finally, the swelling/shrinkage capacity and the enzymatic degradation of adhesives were determined. E-sealant presented a moderate platelet concentration and physiological levels of fibrinogen and thrombin. It clotted 30 s after activation. The microstructure of E-sealant showed a homogeneous fibrillar scaffold with numerous and scattered platelet aggregates. In contrast, Control presented absence of blood cells and amorphous protein deposits. Although in different order of magnitude, both adhesives had similar rheological profiles and viscoelasticity. Control showed a higher hardness but both adhesives presented a pseudoplastic hydrogel nature with a shear thinning behavior. Regarding their adhesiveness, E-sealant presented a higher tensile strength before cohesive failure but their elastic stretching capacity and maximum elongation was similar. While E-sealant presented a significant shrinkage process, Control showed a slight swelling over time. In addition, E-sealant presented a high enzymatic resorption rate, while Control showed to withstand the biodegradation process in a significant way. E-sealant presents optimal biochemical and biomechanical properties suitable for its use as a fibrin sealant with regenerative purposes.

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

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

The value of platelet-rich plasma-derived extracellular vesicles in modern medicine

Platelet-rich plasma (PRP) has been widely used in clinical practice. The mechanism by which PRP promotes tissue repair lies in the release of multiple growth factors upon platelet activation, which accelerates the proliferation and differentiation of repair cells and the synthesis of extracellular matrix. In recent years, as extracellular vesicles (EVs) research has increased and intensified, it has been found that EVs also play an important role in tissue repair. This article provides a comprehensive review of the role of PRP and PRP-derived extracellular vesicles (PRP-EVs) in tissue repair. It discusses the biological characteristics, extraction, identification, activation, and preservation of PRP-EVs. It also reviews their applications in orthopedics and wound repair. The article highlights the importance of PRP-EVs in modern medicine and suggests that they could be a promising natural nanocarrier.

Extra-short implants (≤ 6.5 mm in length) in atrophic and non-atrophic sites to support screw-retained full-arch restoration: a retrospective clinical study

PURPOSE

Increasing scientific evidence support extending the application of short dental implants to non-atrophic dental arches. The purpose of this study has been the evaluation of extra-short implants (≤ 6.5 mm in length) that were placed in atrophic and non-atrophic anatomical sites to support the same prosthesis.

METHODS

For that, a retrospective study was conducted by including complete dentures that were solely supported by extra-short implants in the maxilla and/or the mandible. Clinical data about patients, implants, anatomy, and prosthesis were obtained. Statistical analysis was performed to assess implant- and prosthesis-survival, changes in the marginal bone level and prosthetic complications.

RESULTS

A total of 87 implants in 15 screw-retained complete dentures were assessed. None of the prostheses nor the extra-short implant failed during the follow-up of 27.2 ± 15.4 months. The changes in the mesial and distal marginal bone level were + 0.15 ± 0.51 mm and + 0.11 ± 0.50 mm, respectively. Comparing the implants according to the availability of sufficient bone to place longer implants, indicated the absence of significant differences in the changes of the mesial marginal bone level. However, the changes in the distal marginal bone level showed a statistically significant difference in favor of implants that were placed in non-atrophic sites. Two events of screw loosening were reported that were resolved by retightening the screws.

CONCLUSIONS

Implant- and prosthesis-related outcomes support the use of extra-short implants in atrophic and non-atrophic site to support complete prosthesis.

Plasma Rich in Growth Factors as an Adjuvant Treatment for the Management of Frontal Fibrosing Alopecia: A Retrospective Observational Clinical Study

BACKGROUND

Frontal fibrosing alopecia (FFA) is a scarring alopecia in which the exact etiopathogenesis has not been completely elucidated and the available treatments are not very effective. Plasma rich in growth factors (PRGF) has shown to induce folliculogenesis in hair loss related disorders. However, the scientific evidence when facing FFA is scarce.

OBJECTIVES

The aim of this study was to retrospectively analyze the adjuvant use of PRGF compared to the conventional treatment in the management of FFA.

METHODS

Participants with clinically diagnosed FFA who had been treated with either conventional therapy (Control Group) or conventional therapy combined with PRGF (PRGF Group) were identified from the center's medical records. The clinical assessment was based on the "Frontal Fibrosing Alopecia Severity Score" (FFASS), which was fulfilled during a period of two and 4 years.

RESULTS

This study included 118 patients with clinically diagnosed FFA (Control Group: 57 and PRGF Group: 61). No adverse effects related to the treatments were observed. Both treatments showed to halt the steady progression of hair loss compared to baseline. PRGF treatment also induced significant hair regrowth compared to the Control Group. The scalp inflammation was reduced in response to treatments. The FFASS score indicated that PRGF Group improved the symptoms and severity of FFA in a significant manner.

CONCLUSIONS

The adjuvant use of PRGF may exert long-term beneficial effects on hair loss reduction and might reduce the symptoms and severity of FFA.

Development of a new plasma rich in growth factors membrane with improved optical properties

PURPOSE

The aim of the present work was to develop a fibrin membrane using plasma rich in growth factors (PRGF) technology with improved optical properties to be used for the treatment of ocular surface diseases.

BASIC PROCEDURES

Blood was drawn from three healthy donors, and the volume of PRGF obtained from each donor was divided into two main groups: i) PRGF or ii) platelet-poor plasma (PPP). Each membrane was then used pure or diluted to 90 %, 80 %, 70 %, 60 % and 50 %. The transparency of each of the different membranes was evaluated. The degradation and morphological characterization of each membrane was also performed. Finally, a stability study of the different fibrin membranes was performed.

MAIN FINDINGS

The transmittance test showed that the fibrin membrane with the best optical characteristics was obtained after removal of platelets and dilution of fibrin to 50 % (50 % PPP). No significant differences (p > 0.05) were observed between the different membranes in the fibrin degradation test. The stability test showed that the membrane at 50 % PPP retains its optical and physical characteristics after storage at - 20 °C for 1 month compared to storage at 4 °C.

PRINCIPAL CONCLUSIONS

The present study describes the development and characterization of a new fibrin membrane with improved optical characteristics while maintaining mechanical and biological characteristics. The physical and mechanical properties of the newly developed membrane are preserved after storage for at least 1 month at - 20 °C.

The Efficacy of Platelet-Rich Plasma Injection Therapy in the Treatment of Patients with Achilles Tendinopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Over the past few years, many studies have been conducted to evaluate the effectiveness of platelet-rich plasma (PRP) in treating musculoskeletal conditions. However, there is controversy about its benefits for patients with Achilles tendinopathy.

OBJECTIVE

This study aimed to investigate whether platelet-rich plasma injections can improve outcomes in patients with Achilles tendinopathy.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, Cochrane Library, Web of Science, China Biomedical CD-ROM, and Chinese Science and Technology Journal databases to identify randomised controlled clinical trials that compared the efficacy of PRP injection in patients with Achilles tendinopathy (AT) versus placebo, published between 1 January 1966 and 1 December 2022. Review Manager 5.4.1 software was used for the statistical analysis, and the Jadad score was used to assess the included literature. Only 8 of the 288 articles found met the inclusion criteria.

RESULTS

Our work suggests that: The PRP treatment group had a slightly higher VISA-A score than the placebo group at 6 weeks [MD = 1.92, 95% CI (-0.54, 4.38), I² = 34%], at 12 weeks [MD = 0.20, 95% CI (-2.65 3.05), I² = 60%], and 24 weeks [MD = 2.75, 95% CI (-2.76, 8.26), I² = 87%]). However, the difference was not statistically significant. The Achilles tendon thickness was higher at 12 weeks of treatment in the PRP treatment group compared to the control group [MD = 0.34, 95% CI (-0.04, 0.71), p = 0.08], but the difference was not statistically significant. The VAS-improvement results showed no significant difference at 6 and 24 weeks between the two groups, respectively (MD = 6.75, 95% CI = (-6.12, 19.62), I² = 69%, p = 0.30), and (MD = 10.46, 95% CI = (-2.44 to 23.37), I² = 69%, p = 0.11). However, at 12 weeks of treatment, the PRP injection group showed a substantial VAS improvement compared to the control group (MD = 11.30, 95% CI = (7.33 to 15.27), I² = 0%, p < 0.00001). The difference was statistically significant. The return to exercise rate results showed a higher return to exercise rate in the PRP treatment group than the placebo group [RR = 1.11, 95% CI (0.87, 1.42), p = 0.40]; the difference was not statistically significant.

CONCLUSION

There is no proof that PRP injections can enhance patient functional and clinical outcomes for Achilles tendinopathy. Augmenting the frequency of PRP injections may boost the outcomes, and additionally, more rigorous designs and standardised clinical randomised controlled trials are needed to produce more reliable and accurate results.

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.

Bone-Regenerative Ability of Platelet-Rich Plasma Following Sinus Augmentation with Anorganic Bovine Bone: A Systematic Review with Meta-Analysis

BACKGROUND

The objective of this systematic review is to assess the effect of the adjuvant use of platelet-rich plasma (PRP) and its type on new bone formation by anorganic bovine bone during maxillary sinus floor augmentation procedure.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, and Ovid databases were searched for relevant studies published up to 16 September 2021. Randomized clinical trials (RCTs) and non-randomized controlled clinical trials (CCTs) that reported data on the new bone formation (measured by histomorphometric analysis) were considered. Risk of bias and quality assessment of included studies were evaluated following the Cochrane Handbook for Systematic Reviews of Interventions and the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool. Strength of evidence was assessed following the approach of the Agency for Healthcare Research and Quality (AHRQ) through its evidence-based practice center (AHRQ EPC). The meta-analysis was based on the primary outcome of newly formed bone, for which the standard mean difference was calculated.

RESULTS

After the application of eligibility criteria, six clinical trials (three RCTs and three CCTs) covering 85 maxillary sinus floor elevation procedures were included. The pooled new bone formation value for PRP was 1.67 (95% CI: -0.15 to 3.49; I2: 86%), indicating the absence of significant effect. Plasma rich in growth factors (PRGF) was the pure PRP tested in five of the included studies. When sub-group (type of PRP) meta-analysis was performed, significantly higher new bone formation was observed in the PRGF group [2.85 (95% CI: 0.07 to 5.64; I2: 88%)] in comparison to the control group.

CONCLUSIONS

A beneficial effect on new bone formation after maxillary sinus floor elevation can be obtained when anorganic bovine bone is mixed with PRGF.

Platelet-Derived Exosomes in Atherosclerosis

Atherosclerosis (AS), the main cause of many cardiovascular diseases (CVDs), is a progressive inflammatory disease characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. The result is the thickening and clogging of these vessel walls. Several cell types are directly involved in the pathological progression of AS. Among them, platelets represent the link between AS, inflammation, and thrombosis. Indeed, besides their pivotal role in hemostasis and thrombosis, platelets are key mediators of inflammation at injury sites, where they act by regulating the function of other blood and vascular cell types, including endothelial cells (ECs), leukocytes, and vascular smooth muscle cells (VSMCs). In recent years, increasing evidence has pointed to a central role of platelet-derived extracellular vesicles (P-EVs) in the modulation of AS pathogenesis. However, while the role of platelet-derived microparticles (P-MPs) has been significantly investigated in recent years, the same cannot be said for platelet-derived exosomes (P-EXOs). For this reason, this reviews aims at summarizing the isolation methods and biological characteristics of P-EXOs, and at discussing their involvement in intercellular communication in the pathogenesis of AS. Evidence showing how P-EXOs and their cargo can be used as biomarkers for AS is also presented in this review.

Patient-Reported Quality of Life versus Physical Examination in Treating Temporomandibular Disorders with Intra-Articular Platelet-Rich Plasma Injections: An Open-Label Clinical Trial

Temporomandibular disorders, often manifested by articular pain, limitation of the mouth opening range, and unpleasant acoustic symptoms originating from inside the joint, have been associated with reduced quality of life. These symptoms, among others, can be treated with intra-articular injections of various substances, including repeated platelet-rich plasma (PRP) administration. The reported study was designed as an uncontrolled open-label clinical trial of consecutive cases. The participants completed a Fonseca questionnaire and evaluated acoustic symptoms, and spontaneous and provoked pain on VAS, and were subjected to a physical examination before, during, and after PRP therapy. The total Fonseca questionnaire results were statistically significantly (p < 0.05) correlated with 340 out of 348 (98%) other variables. The fully subjective assessment of the presence and intensity of acoustic symptoms coming from the temporomandibular joints was correlated with the physical examination results (0.45-0.63) and the maximum mouth opening with the maximum pain-free mouth opening (0.73-0.87). There were no correlations observed between the patient's and the physician's assessment of mandibular mobility. The Fonseca questionnaire seems to cover the entire spectrum of temporomandibular disorders, making it a balanced tool for assessing the quality of life in TMDs. However, it is worth considering extending the standard 3-point response scale to an 11-point one. The patient is somewhat able to perform a self-diagnosis with regard to the acoustic symptoms, but it is not possible for them to determine without measurement whether the range of mandibular mobility is appropriate..

Unravelling Alveolar Bone Regeneration Ability of Platelet-Rich Plasma: A Systematic Review with Meta-Analysis

Background: This systematic review aims to evaluate the efficacy of the available platelet-rich plasma (PRP) products and composition to regenerate alveolar bone after tooth extraction. Methods: PubMed, Cochrane Central Register of Controlled Trials, and EBSCO databases were searched up to 2 July 2021. Only randomized clinical trials using leukocyte-rich plasma (L-PRP) or pure-platelet rich plasma (P-PRP) for bone regeneration in alveolar ridge preservation were selected. The following outcomes were considered: (1) new bone formation (primary outcome) and (2) bone density (secondary outcome). A meta-analysis for PRP, P-PRP, and L-PRP using a fixed effect model was performed with Review Manager 5.4 software. Overall evidence was qualified using GRADE. Results: Six randomized clinical trials from 2639 unique articles initially identified met the inclusion criteria. The meta-analysis showed a significant effect of the P-PRP on the outcome of new bone formation (SMD, 1.44; 95% CI, 0.84 to 2.03) for P-PRP treatment. No information was retrieved for L-PRP. A statistically significant difference was also observed in the P-PRP group for bone density outcome (SMD, 1.24; 95% CI, 0.81 to 1.68). The L-PRP treated sockets also showed higher bone density (SMD, 0.88; 95% CI, 0.31 to 1.45) in comparison to control sockets. The quality of evidence was moderate for both outcomes in the P-PRP group and low for the L-PRP group. Conclusions: Despite the limitations of the included studies, our data suggest that P-PRP, in comparison to unassisted healing, can improve alveolar bone regenerative potential. However, more high-quality clinical studies are needed.

Autologous Platelet Rich Plasma (PRGF) Preserves Genomic Stability of Gingival Fibroblasts and Alveolar Osteoblasts after Long-Term Cell Culture

Plasma rich in growth factors (PRGF) has several applications in dentistry that may require repeated applications of PRGF. Furthermore, it has been used for ex vivo expansion of human origin cells for their clinical application. One of the most relevant issues in these applications is to guarantee the genetic stability of cells. In this study, the chromosomal stability of gingival fibroblasts and alveolar osteoblasts after long-term culture was evaluated. Cells were expanded with PRGF or foetal bovine serum (FBS) as a culture medium supplement until passage 7 or 8 for gingival fibroblast or alveolar osteoblasts, respectively. A comparative genomic hybridization (CGH) array was used for the genetic stability study. This analysis was performed at passage 3 and after long-term culture with the corresponding culture medium supplements. The cell proliferative rate was superior after PRGF culture. Array CGH analysis of cells maintained with all the three supplements did not reveal the existence of alterations in copy number or genetic instability. The autologous PRGF technology preserves the genomic stability of cells and emerges as a safe substitute for FBS as a culture medium supplement for the clinical translation of cell therapy.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULT

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

CONCLUSION

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

Effects of Super-Activated Platelet Lysate on Early Healing of Tooth Extraction Sockets in Rats

Purpose

To evaluate the effect of super-activated platelet lysate (sPL) on wound healing of tooth extraction sockets in rats.

Methods

Rat models of the tooth extraction socket were established. Thirty-six rats were divided into control and sPL groups and sacrificed on days 7, 14, and 28 after tooth extraction. Bone formation in tooth extraction sockets were observed by microscopic computed tomography (micro-CT) and hematoxylin and eosin (HE) staining; osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), interleukin 6(IL-6), and tumor necrosis factor-alpha (TNF-α) proteins were detected by immunohistochemistry; and chemokine and osteogenic gene expressions were detected by polymerase chain reaction (PCR).

Results

sPL accelerated soft tissue wound healing in the extraction socket of rats. Micro-CT showed that the amount of bone formation and bone volume fraction were higher in the sPL group than the control 14 days after extraction. HE staining showed promotion of the formation of bony trabeculae by sPL in the apical third of the extraction socket 7 days after extraction and more mature and organized bony trabeculae in the sPL group than the control 14 days after extraction; mature bony trabeculae filling most of the fossa with lesser bone porosity in the socket in the sPL group than the control 28 days after extraction. Immunohistochemistry showed that sPL induced OPG expressions 7 and 14 days after tooth extraction but did not affect the RANKL expression while transiently promoting the IL-6 expression 7 days after extraction. PCR showed that sPL promoted chemokine expressions 7 and 14 days after extraction. The expressions of osteogenesis-related factors were higher in the sPL group than the control 7 and 28 days after extraction, while the opposite trend was observed 14 days after extraction.

Conclusion

sPL has a transient pro-inflammatory effect and promotes soft tissue healing and bone formation during early wound healing of extraction sockets in rats.

Advanced Nanofiber-Based Scaffolds for Achilles Tendon Regenerative Engineering

The Achilles tendon (AT) is responsible for running, jumping, and standing. The AT injuries are very common in the population. In the adult population (21–60 years), the incidence of AT injuries is approximately 2.35 per 1,000 people. It negatively impacts people’s quality of life and increases the medical burden. Due to its low cellularity and vascular deficiency, AT has a poor healing ability. Therefore, AT injury healing has attracted a lot of attention from researchers. Current AT injury treatment options cannot effectively restore the mechanical structure and function of AT, which promotes the development of AT regenerative tissue engineering. Various nanofiber-based scaffolds are currently being explored due to their structural similarity to natural tendon and their ability to promote tissue regeneration. This review discusses current methods of AT regeneration, recent advances in the fabrication and enhancement of nanofiber-based scaffolds, and the development and use of multiscale nanofiber-based scaffolds for AT regeneration.

Platelet-Rich Plasma as an Alternative to Xenogeneic Sera in Cell-Based Therapies: A Need for Standardization

There has been an explosion in scientific interest in using human-platelet-rich plasma (PRP) as a substitute of xenogeneic sera in cell-based therapies. However, there is a need to create standardization in this field. This systematic review is based on literature searches in PubMed and Web of Science databases until June 2021. Forty-one studies completed the selection criteria. The composition of PRP was completely reported in less than 30% of the studies. PRP has been used as PRP-derived supernatant or non-activated PRP. Two ranges could be identified for platelet concentration, the first between 0.14 × 10⁶ and 0.80 × 10⁶ platelets/µL and the second between 1.086 × 10⁶ and 10 × 10⁶ platelets/µL. Several studies have pooled PRP with a pool size varying from four to nine donors. The optimal dose for the PRP or PRP supernatant is 10%. PRP or PRP-derived supernatants a have positive effect on MSC colony number and size, cell proliferation, cell differentiation and genetic stability. The use of leukocyte-depleted PRP has been demonstrated to be a feasible alternative to xenogeneic sera. However, there is a need to improve the description of the PRP preparation methodology as well as its composition. Several items are identified and reported to create guidelines for future research.

Autologous Fat Plus Platelet-Rich Plasma versus Autologous Fat Alone on Sulcus Vocalis

Sulcus vocalis is a frequent cause of glottic insufficiency that leads to incomplete vocal fold closure during phonation. Type II sulcus vocalis is defined as a partial defect of the lamina propria (LP). Treatment with fillers, such as fat or hyaluronic acid (HA), in the vocal folds is widely used, but the duration of effect is variable. Platelet-rich plasma (PRP) can enhance the survival of autologous fat in fat grafting, and also is used to treat sulcus vocalis. This study aimed to compare the effectiveness of autologous fat graft versus fat graft plus PRP to treat type II sulcus vocalis. Thirty-four patients with a voice handicap index (VHI) ≥ 11 were randomized to two groups, which received LP injections of fat graft (n = 17) or fat graft plus PRP (n = 17). At 1 month and 6 months after injection, the VHI decreased significantly in both groups. The fat plus PRP group had better Jitter, Shimmer, and noise to harmonic ratio (NHR) in 1 month and 6 months after surgery. The fat plus PRP group resulted in lower VHI scores one month after surgery, and stroboscopy revealed sustained smaller gaps after six months. These results indicate that a combination of fat graft plus PRP is safe and effective for treating sulcus vocalis type II and associated vocal atrophy.

Intra-Articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Degree of Efficacy

Knee osteoarthritis (OA) is estimated to affect more than 10% of the population, with a lifetime risk of 45%. Contemporary guidelines advise control of body weight, therapeutic physical exercise, drug treatment (oral non-steroidal anti-inflammatory drugs, paracetamol, opioids), and mechanical aids (walking aids, braces, orthoses). Nevertheless, these treatments typically have only short-term benefits. Intra-articular corticosteroids are typically advised, but only for short-term pain alleviation, given that their benefits last only a few weeks. The efficacy of hyaluronic acid is controversial. When the aforesaid options fail, total knee arthroplasty is generally recommended as an efficacious treatment. However, it is costly and can involve medical and postoperative complications. Therefore, determining alternate safe and effective treatments for knee OA is paramount. Platelet-rich plasma (PRP) has lately been investigated for the treatment of knee OA. This article reviews recent knowledge concerning PRP’s molecular mechanisms of action. The effectiveness of intra-articular PRP injections in the knee joint remains controversial, although most recent publications show pain alleviation in the short term. Orthopedic surgeons treating people with knee OA are becoming increasingly interested in PRP, despite indecisive clinical data and basic science information. Further studies comparing PRP with placebo are required.

Intraarticular injections of platelet rich plasma and plasma rich in growth factors with arthrocenthesis or arthroscopy in the treatment of temporomandibular joint disorders: A systematic review

Intra-articular platelet rich plasma injections [PRP] or platelet rich growth factors [PRGF] injections have been used as therapeutic treatment options for patients with temporomandibular joint disorder [TMD] in recent years. The purpose of this paper is to evaluate the level of the available scientific evidence in the current literature on the benefits of applying PRP or PRGF injections to patients with TMD simultaneously or after arthrocentesis or arthroscopy to reduce post-operative pain and improve temporomandibular joint function. This systematic review was conducted according to PRISMA criteria and an electronic database search was carried out in the PubMed, Scopus and Cochrane databases during May 2021. The patients in the study group were injected with intra-articular PRP or PRGF simultaneously or after arthrocentesis or arthroscopy while the patients in the control group had arthrocentesis or arthroscopy without an intra-articular injection or received an injection of hyaluronic acid or Ringer's lactate solution. Eight randomised controlled clinical trials were selected. The PRP and PRGF intra-articular injections demonstrated significant differences in terms of pain reduction in three studies and improved mandibular function in two. The treatment with PRP or PRGF intra-articular injections demonstrated slightly better clinical results but of little significance in comparison with the control group. Evidence of their effectiveness is crucial to establish them as non-invasive treatments and as an affordable option for treating some types of TMDs. In accordance with Evidence-based dentistry principles, this review has been assigned a C recommendation.

Enhanced Platelet-Rich Plasma (ePRP) Stimulates Wound Healing through Effects on Metabolic Reprogramming in Fibroblasts

As a source of growth factors for expediting wound healing and tissue regeneration, plasma-rich plasma (PRP) has been extensively applied in diverse fields including orthopaedics, ophthalmology, oral and maxillofacial surgery, dentistry, and gynaecology. However, the function of PRP in metabolic regulations remains enigmatic. A standardized method was devised herein to enrich growth factors and to lyophilize it as enhanced PRP (ePRP) powder, which could become ubiquitously available without mechanical centrifugation in clinical practice. To identify metabolic reprogramming in human dermal fibroblasts under ePRP treatment, putative metabolic targets were identified by transcriptome profiling and validated for their metabolic effects and mechanism. ePRP does not only promote wound healing but re-aligns energy metabolism by shifting to glycolysis through stimulation of glycolytic enzyme activity in fibroblasts. On the contrary, oxygen consumption rates and several mitochondrial respiration activities were attenuated in ePRP-treated fibroblasts. Furthermore, ePRP treatment drives the mitochondrial resetting by hindering the mitochondrial biogenesis-related genes and results in a dampened mitochondrial mass. Antioxidant production was further increased by ePRP treatment to prevent reactive oxygen species formation. Besides, ePRP also halts the senescence progression of fibroblasts by activating SIRT1 expression. Importantly, the glycolytic inhibitor 2-DG can completely reverse the ePRP-enhanced wound healing capacity, whereas the mitochondrial inhibitor oligomycin cannot. This is the first study to utilize PRP for comprehensively investigating its effects on the metabolic reprogramming of fibroblasts. These findings indicate that PRP’s primary metabolic regulation is to promote metabolic reprogramming toward glycolytic energy metabolism in fibroblasts, preserving redox equilibrium and allowing anabolic pathways necessary for the healing and anti-ageing process.

Platelet-rich plasma-derived extracellular vesicles: A superior alternative in regenerative medicine?

Platelet-rich plasma (PRP), due to its promising therapeutic properties, has been used in regenerative medicine for more than 30 years and numerous encouraging outcomes have been obtained. Currently, by benefiting from new insights into PRP mechanisms and the excellent performance of extracellular vesicles (EVs) in the field of tissue repair and regeneration, studies have found that a large number of EVs released from activated platelets also participate in the regulation of tissue repair. A growing number of preclinical studies are exploring the functions of PRP-derived EVs (PRP-EVs), especially in tissue regeneration. Here, we summarize the latest progress in PRP-EVs as a superior alternative cell-free therapeutic strategy in regenerative medicine, clarify their underlying molecular mechanisms, and discuss the advantages and limitations of the upcoming clinical applications. This review highlights the potential of PRP-EVs to replace the application of PRP or even become a superior alternative in regenerative medicine.

Enrichment of plasma in platelets and extracellular vesicles by the counterflow to erythrocyte settling

In order to prepare optimal platelet and extracellular vesicle (EV)-rich plasma for the treatment of chronic temporal bone inflammation, we studied effects of centrifugation parameters on redistribution of blood constituents in blood samples of 23 patients and 20 volunteers with no record of disease. Concentrations of blood cells and EVs were measured by flow cytometry. Sample content was inspected by scanning electron microscopy. A mathematical model was constructed to interpret the experimental results. The observed enrichment of plasma in platelets and EVs after a single spin of blood depended on the erythrocyte sedimentation rate, thereby indicating the presence of a flow of plasma that carried platelets and EVs in the direction opposite to settling of erythrocytes. Prolonged handling time correlated with the decrease of concentration of platelets and larger EVs in platelet and EV-rich plasma (PVRP), R = -0.538, p = 0.003, indicating cell fragmentation during the processing of samples. In further centrifugation of the obtained plasma, platelet and EV enrichment depended on the average distance of the sample from the centrifuge rotor axis. Based on the agreement of the model predictions with observations, we propose the centrifugation protocol optimal for platelet and EV enrichment and recovery in an individual sample, adjusted to the dimensions of the centrifuge rotor, volume of blood and erythrocyte sedimentation rate.[Figure: see text].

The effect of platelet-rich plasma injection on chronic Achilles tendinopathy and acute Achilles tendon rupture

Several clinical trials exploring the effect of platelet-rich plasma (PRP) on Achilles tendon rupture (ATR) or Achilles tendinopathy (AT) have been published. However, current evidence is limited to small-sized trials. This study aims to evaluate whether PRP improves the outcomes of ATR or AT. PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched to identify randomized controlled trials comparing PRP injection versus placebo for ATR or AT. Eleven studies with 574 patients were included. Quantitative synthesis suggested that compared with placebo, AT patients in PRP group had higher VISA-A score improvement at six-week follow-up (mean difference (MD) = 2.64; 95% CI) = 1.12 to 4.15). However, there was no significant difference between two groups for VISA-A score improvement at three-month follow-up (MD = 0.93; 95% CI = -2.75 to 4.62), or 6-month follow-up (MD = 5.46; 95% CI = -1.19 to 12.11). In ATR patients, quantitative synthesis suggested that no significant difference was seen between PRP and control group at 3-month, 6-month, and 1-year follow-up. In addition, no significant difference was detected between the two groups in improving tendon thickness and pain for AT patients, and no significant difference was seen in improving heel-rise work, maximum heel-rise height, dorsal and plantar flexion, rate of returning to sports activities, and complication for ATR patients. To conclude, no evidence indicates that PRP injection can improve the patient-reported/clinical/functional outcomes of AT or ATR. The increasing times of PRP injection could improve the outcomes, and further clinical randomized controlled trials are expected to be conducted to verify this hypothesis.

Mechanisms of Action and Efficacy of Hyaluronic Acid, Corticosteroids and Platelet-Rich Plasma in the Treatment of Temporomandibular Joint Osteoarthritis-A Systematic Review

Temporomandibular joint osteoarthritis (TMJ OA) is a low-inflammatory disorder with multifactorial etiology. The aim of this review was to present the current state of knowledge regarding the mechanisms of action and the efficacy of hyaluronic acid (HA), corticosteroids (CS) and platelet-rich plasma (PRP) in the treatment of TMJ OA.: The PubMed database was analyzed with the keywords: "(temporomandibular joint) AND ((osteoarthritis) OR (dysfunction) OR (disorders) OR (pain)) AND ((treatment) OR (arthrocentesis) OR (arthroscopy) OR (injection)) AND ((hyaluronic acid) OR (corticosteroid) OR (platelet rich plasma))". After screening of 363 results, 16 studies were included in this review. Arthrocentesis alone effectively reduces pain and improves jaw function in patients diagnosed with TMJ OA. Additional injections of HA, either low-molecular-weight (LMW) HA or high-molecular-weight (HMW) HA, or CS at the end of the arthrocentesis do not improve the final clinical outcomes. CS present several negative effects on the articular cartilage. Results related to additional PRP injections are not consistent and are rather questionable. Further studies should be multicenter, based on a larger group of patients and should answer the question of whether other methods of TMJ OA treatment are more beneficial for the patients than simple arthrocentesis.