Platelet-rich Plasma-derived Exosomes as Novel Frontier in Regenerative Medicine

<h3>Introduction and history</h3> While regenerative medicine may seem like a novel intervention in the chronic pain armamentarium, its evolution and in a sense its definition has been intricately related to...

Effects of platelet-rich plasma and carbonated hydroxyapatite combination on cranial defect Bone Regeneration: An animal study

CORR Synthesis: What Is the Role of Platelet-rich Plasma Injection in the Treatment of Tendon Disorders?

Platelets are involved in hemostasis, wound healing, and tumor growth. Autologous blood products are commonly used to facilitate healing in a variety of clinical surgery applications. Recently, it was shown that platelet-rich plasma (PRP) has more specific growth factors that participate in the healing process. This study investigated the expression of PRP growth factors and evaluated their potential role in the cartilage regeneration using primary isolated chondrocytes. PRP obtained from New Zealand White rabbit by low speed centrifugation. Extracted PRPs contained 6-10 × 10(6) platelet/μl and concentration of platelets was slightly variable. Primary isolated chondrocytes from the same rabbits were cultured and treated with 0.1-20% PRP. The cells were collected and examined by reverse transcription-polymerase chain reaction and cytochemical staining. The expression of sex determining region Y-box 9, transforming growth factor-beta, vascular endothelial growth factor, and chondromdulin-I was increased in chondrocyte cultures with 10% PRP by time-dependent manner. To maintain the integrity of the cartilage, the proteoglycan contents were also up-regulated from the mRNA of aggrecan and positive Safranin-O staining in PRP concentration- and time-dependent manner. PRP provides crucial growth factors related to chondrocyte proliferation and differentiation through time-sequential modulation. Controlled in vivo trials for cartilage regeneration are needed.

Relevance. Platelet-rich plasma (PRP) is a centrifuged fraction of autolytic peripheral blood with a high concentration of platelets. Platelet-rich plasma functions by releasing cytokines and growth factors contained in the alpha granules of platelets: platelet-derived growth factor (PDGF-aa, PDGF-ab), transforming growth factor-beta (TBF-b1, TBF-b2), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), epidermal growth factor (EGF), insulin-like growth factor (IGF), antiheparin growth factor, platelet-activating factor, which stimulate regenerative cellular processes, angiogenesis, and collagen synthesis. The aim of the study was to investigate the application of platelet-rich plasma (PRP) in surgical practice as a means to stimulate reparative processes in body tissues and enhance the treatment of chronic wounds of various etiologies. A retrospective analysis of data from the world scientific literature was performed, which investigated the purpose of using platelet-rich plasma in surgical practice. Results. The study showed that platelet-rich plasma has a wide range of applications in medicine. The use of PRP in surgical practice enables to accelerate the closure of trophic ulcers, diabetic foot ulcers, and chronic wounds of various etiologies. The analysis of systematized data showed that the use of PRP accelerates the formation of epithelialization and reduces the time of closure of the ulcer defect, promotes the maturation of mature granulation tissue and prevents infection of clean ulcers and wounds, enhances cell proliferation and increases the rate of regenerative processes, as well as reduces the level of amputation and disability.

Editorial Commentary: Platelet-Rich Plasma Injections Produced a Significant Improvement in Most Patients With Rotator Cuff Tendinopathy

BackgroundThere is variability in individual response to platelet-rich plasma (PRP) therapy in tennis elbow treatment. Genetic variation, especially within genes encoding growth factors may influence the observed inter-individual differences. The purpose of this study was to identify polymorphic variants of the platelet-derived growth factor beta polypeptide gene (PDGFB) that determine an improved individual response to PRP therapy in tennis elbow patients.MethodsThis prospective cohort study was designed in accordance with STROBE and MIBO guidelines. A cohort of 107 patients (132 elbows, 25 bilateral) was studied, including 65 females (77 elbows) and 42 males (55 elbows), aged 24–64 years (median 46.00 ± 5.50), with lateral elbow tendinopathy treated with autologous PRP injection. The effectiveness of PRP therapy was recorded in all subjects at 2, 4, 8, 12, 24 and 52 weeks after PRP injection using the Visual Analog Scale (VAS), quick version of Disabilities of the Arm, Shoulder and Hand score (QDASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE). In order to determine the PDGFB variants with the best response to PRP therapy, patient reported outcome measures were compared between individual genotypes within studied polymorphic variants (rs2285099, rs2285097, rs2247128, rs5757572, rs1800817 and rs7289325). The influence of single nucleotide polymorphisms on blood and PRP parameters, including the concentration of PDGF-AB and PDGF-BB proteins was also analyzed.ResultsOur analysis identified genetic variants of the PDGFB gene that lead to a better response to PRP therapy. The TT (rs2285099) and CC (rs2285097) homozygotes had higher concentration of platelets in whole blood than carriers of other genotypes (p = 0.018) and showed significantly (p < 0.05) lower values of VAS (weeks 2–12), QDASH and PRTEE (weeks 2–24). The rs2285099 and rs2285097 variants formed strong haplotype block (r2 = 98, D’=100). The AA homozygotes (rs2247128) had significantly lower values of VAS (weeks 4–52), QDASH and PRTEE (weeks 8, 12).ConclusionsPDGFB gene’s polymorphisms increase the effectiveness of PRP therapy in tennis elbow treatment. Genotyping two polymorphisms of the PDGFB gene, namely rs2285099 (or rs2285097) and rs2247128 may be a helpful diagnostic tool while assessing patients for PRP therapy and modifying the therapy to improve its effectiveness.

Platelet-rich plasma (PRP) is a plasma component containing high concentrations of platelets, growth factors, antioxidants and proliferative properties. To mitigate the negative effects of cryopreservation on ram semen by utilising PRP. Semen was collected from six rams twice a week for 3weeks during the breeding season. Pooling was performed by dilution with tris+egg yolk diluent. Pooling was divided into three equal parts and re-diluted with diluents containing control (0% PRP), 5% PRP and 10% PRP. Sperms were frozen in an automatic freezing device and stored in liquid nitrogen. After thawing, spermatological, flow-cytometric, oxidative stress, cholesterol, fatty acid, ELISA, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analyses were performed. Compared with the control group, the 5% PRP group exhibited a significant increase in progressive motility, viability and cholesterol ratios, glutathione-peroxidase activity, CATSPER1 (Cation Channel of Sperm), CATSPER3, vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) levels and KCNJ11 (Potassium Channel, Inwardly Rectifying, Subfamily J, Member 11), HSA-MIR-181A, HSA-MIR-150 and HSA-MIR-374 transcripts. Apoptotic protein, malondialdehyde and HSA-MIR-410, OAR-MIR-10B, BTA-MIR-22-3P and RNO-MIR-494 transcripts were decreased in 5% PRP group compared with control. PRP supplementation at 10% increased dead sperm and heptadecenoic acid ratios, VEGF and PDGF levels and HSA-MIR-410, PPY-MIR-16, CFA-MIR-199, HSA-MIR-181A, HSA-MIR-150, OAR-MIR-127, HSA-LET-7A and HSA-MIR-374 transcripts as well as CATSPER3, HSD3β2, PDGFB and VEGFA proteins compared with the control. PRP supplementation at 10% significantly decreased plasma membrane integrity, insulin-like growth factor 1 (IGF1) level and CATSPER3 and KCNJ11 transcripts compared with the control. The addition of 5% PRP before cryopreservation has beneficial effects on the functional and molecular properties of frozen-thawed ram spermatozoa, whereas the addition of 10% PRP has negative effects. Five per cent PRP should be added to ram semen diluents.

Editorial Commentary: Platelet-Rich Plasma for Rotator Cuff Repairs: No Evidence for Improved Long-Term Outcomes … Yet!

Platelet‐rich plasma (PRP) is widely used in regenerative medicine because of its high concentrations of various growth factors and platelets. However, the distribution of blood cell components has not been investigated in either PRP or other PRP derivatives. In this study, we focused on plasma rich in growth factors (PRGF), a PRP derivative, and analyzed the distributions of platelets and white blood cells (WBCs). Peripheral blood samples were collected from healthy volunteers (N = 14) and centrifuged to prepare PRGF and PRP. Blood cells were counted using an automated hematology analyzer. The effects of PRP and PRGF preparations on cell proliferation were determined using human periosteal cells. In the PRGF preparations, both red blood cells and WBCs were almost completely eliminated, and platelets were concentrated by 2.84‐fold, whereas in the PRP preparations, both platelets and WBCs were similarly concentrated by 8.79‐ and 5.51‐fold, respectively. Platelet counts in the PRGF preparations were positively correlated with platelet counts in the whole blood samples, while the platelet concentration rate was negatively correlated with red blood cell counts in the whole blood samples. In contrast, platelet counts and concentration rates in the PRP preparations were significantly influenced by WBC counts in whole blood samples. The PRP preparations, but not the PRGF preparations, significantly suppressed cell growth at higher doses in vitro. Therefore, these results suggest that PRGF preparations can clearly be distinguished from PRP preparations by both inclusion of WBCs and dose‐dependent stimulation of periosteal cell proliferation in vitro.

Background: Small extracellular vesicles (sEVs) circulate throughout the body via blood. They contain various cargoes, including microRNA (miRNA), and have known roles in modulating inflammation and disease. Plasma-based orthobiologics such as platelet-rich plasma (PRP) are commonly used to treat osteoarthritis and synovitis. The role of extracellular vesicle–derived miRNA in PRP therapy is unknown. Purpose: To characterize sEVs from PRP and platelet-poor plasma (PPP) by using known sEV markers, quantify sEV miRNA content, and evaluate sEV bioactivity via an in vitro IL-1β–induced synovitis model. Study Design: Controlled laboratory study. Methods: sEVs were isolated from leukocyte-rich PRP, leukocyte-poor PRP, and PPP by precipitation or tangential flow methods. The size and concentration of sEVs were quantified, and their cellular origin was determined. The total miRNA content of sEVs was analyzed, and the cellular pathways affected by the sEV miRNA cargo were determined. The effect of plasma-derived sEVs on synoviocyte proliferation and response to inflammation was determined in an IL-1β–induced synovitis model. sEVs were also fluorescently stained, and incorporation was visualized through fluorescent imaging. Results: sEVs isolated from plasma were predominantly derived from platelets, with a small subset derived from monocytes and macrophages. miRNA contained within sEVs targeted various cellular pathways, including metabolism, PI3K-AKT, and calcium signaling. IL-1β–treated synoviocytes treated with native PRP, PPP, or their isolated sEVs were protected from the catabolic effects of IL-1β as compared with the same treatments depleted of sEVs. Conclusion: sEVs were present in all tested fluids. Most sEVs were derived from platelets, with a small subset from white blood cells. miRNA within the sEV affected various cell signaling pathways associated with inflammation, and plasma sEVs were crucial in protecting synoviocytes from inflammation. Clinical Relevance: sEVs in PRP are one mechanism of action by which PRP can protect synoviocytes from inflammation.

Platelet-rich plasma is a blood-derived fraction that contains a high concentration of platelets and growth factors. It was proposed that the use of this platelet concentrate stimulates tissue repair. However, little is known about the biologic response of gingival fibroblasts to platelet's derived growth factors. In the present study, we evaluated whether platelet-rich plasma modulated cell adhesion, cell migration, and myofibroblastic differentiation in primary cultures of human gingival fibroblasts. We studied the response of primary cultures of gingival fibroblasts to thrombin-activated platelet-rich plasma fractions. Cell adhesion was evaluated through a colorimetric assay. Cell spreading, actin cytoskeleton remodeling, and focal adhesion distribution were assessed through light and immunofluorescence microscopy. Cell migration was analyzed using a bicameral cell culture system. Smooth muscle actin production was studied through Western blotting. Exposure of gingival fibroblasts to platelet-rich plasma stimulated adhesion and spreading of cells on fibronectin matrices, the development of actin-enriched cellular extensions, and formation of focal adhesions. Platelet-rich plasma also promoted cell migration and invasion through a reconstituted basement membrane matrix. Differentiation into the myofibroblastic phenotype, assessed through the production of smooth muscle actin, was also stimulated by platelet-rich plasma preparations. Platelet-rich plasma may modulate several cell responses potentially involved in wound healing such as cell adhesion, cell migration, and myofibroblastic differentiation.

This study is conducted to determine the effect of different kinds of bone substitutes and collagen on the concentration of platelet-derived growth factor (PDGF) and transforming growth factor beta-1 (TGF beta-1) in platelet-rich plasma (PRP). PRP is treated with thrombin, hydroxyapatite (HA), and thrombin, HA alone, collagen-grafted HA, calcium metaphosphate (CMP), and collagen-grafted CMP. The concentrations of PDGF-AB and TGF beta-1 are measured. After PRP treated with HA and CMP, the concentrations of PDGF and TGF beta-1 are not significantly different from the concentration of them in PRP alone. The concentrations of PDGF in PRP with collagen-grafted HA and collagen-grafted CMP are significantly higher than that of PRP with HA and CMP. The concentrations of PDGF and TGF beta-1 in PRP with collagen-grafted CMP are higher than with collagen-grafted HA. The results of multiple regression analysis show that PDGF increased with the use of collagen and thrombin, and is higher in native whole blood with higher platelet counts. However, PDGF decreased with the use of HA. In conclusion, HA and CMP do not seem to be able to activate platelets by themselves. However, if they had collagen grafted onto them, they could activate platelets and release growth factors.

Platelet-rich plasma (PRP) is an autologous biologic product used in several fields of medicine for tissue repair due to the regenerative capacity of the biomolecules of its formulation. PRP consists of a plasma with a platelet concentration higher than basal levels but with basal levels of any biomolecules present out of the platelets. Plasma contains extraplatelet biomolecules known to enhance its regenerative properties. Therefore, a PRP containing not only a higher concentration of platelets but also a higher concentration of extraplatelet biomolecules that could have a stronger regenerative performance than a standard PRP. Considering this, the aim of this work is to develop a new method to obtain PRP enriched in both platelet and extraplatelet molecules. The method is based on the absorption of the water of the plasma using hydroxyethyl acrylamide (HEAA)-based hydrogels. A plasma fraction obtained from blood, containing the basal levels of platelets and proteins, was placed in contact with the HEAA hydrogel powder to absorb half the volume of the water. The resulting plasma was characterized, and its bioactivity was analyzed in vitro. The novel PRP (nPRP) showed a platelet concentration and platelet derived growth factor (PDGF) levels similar to the standard PRP (sPRP), but the concentration of the extraplatelet growth factors IGF-1 (p < 0.0001) and HGF (p < 0.001) were significantly increased. Additionally, the cells exposed to the nPRP showed increased cell viability than those exposed to a sPRP in human dermal fibroblasts (p < 0.001) and primary chondrocytes (p < 0.01). In conclusion, this novel absorption-based method produces a PRP with novel characteristics compared to the standard PRPs, with promising in vitro results that could potentially trigger improved tissue regeneration capacity.

Platelet-rich plasma (PRP) is a promising tool in regenerative medicine because it stimulates tissue repair and regeneration. PRP contains a high concentration of platelets, growth factors, and cytokines involved in the healing process. This editorial paper aims to give an overview of PRP in regenerative medicine and its potential applications in various medical fields such as orthopedics, dentistry, dermatology, and wound healing. PRP can be integrated with other regenerative therapies, such as stem cell and gene therapy, to enhance tissue repair and regeneration. Therefore, PRP holds great promise as a regenerative medicine tool, and further research is needed to optimize its use and develop standardized protocols for its preparation and application.