Platelet-rich fibrin increases cell attachment, proliferation and collagen-related protein expression of human osteoblasts

Platelet rich fibrin as a bioactive matrix with proosteogenic and proangiogenic properties on human healthy primary cells in vitro

Blood concentrates like platelet rich fibrin (PRF) have been established as a potential autologous source of cells and growth factors with regenerative properties in the field of dentistry and regenerative medicine. To further analyze the effect of PRF on bone tissue regeneration, this study investigated the influence of liquid PRF matrices on human healthy primary osteoblasts (pOB) and co-cultures composed of pOB and human dermal vascular endothelial cells (HDMEC) as in vitro model for bone tissue regeneration. Special attention was paid to the PRF mediated influence on osteoblastic differentiation and angiogenesis. Based on the low-speed centrifugation concept, cells were treated indirectly with PRF prepared with a low (44 g) and high relative centrifugal force (710 g) before the PRF mediated effect on osteoblast proliferation and differentiation was assessed via gene and protein expression analyses and immunofluorescence. The results revealed a PRF-mediated positive effect on osteogenic proliferation and differentiation accompanied by increased concentration of osteogenic growth factors and upregulated expression of osteogenic differentiation factors. Furthermore, it could be shown that PRF treatment resulted in an increased formation of angiogenic structures in a bone tissue mimic co-culture of endothelial cells and osteoblasts induced by the PRF mediated increased release of proangiogenic growth factors. The effects on osteogenic proliferation, differentiation and vascularization were more evident when low RCF PRF was applied to the cells. In conclusion, PRF possess proosteogenic, potentially osteoconductive as well as proangiogenic properties, making it a beneficial tool for bone tissue regeneration.

How to Improve Meniscal Repair through Biological Augmentation: A Narrative Review

Since the role of the menisci in knee stability, proprioception, and homeostasis has been well established, significant efforts have been made to repair meniscal tears, resulting in excellent clinical outcomes and a reduction in the progression of knee osteoarthritis (OA). However, varying failure rates have been reported, raising questions regarding the healing potential in cases of complex injuries, poorly vascularized and degenerated areas, and generally in the presence of unfavorable biological characteristics. Therefore, over the last few decades, different strategies have been described to increase the chances of meniscal healing. Biological augmentation of meniscal repair through various techniques represents a safe and effective strategy with proven clinical benefits. This approach could reduce the failure rate and expand the indications for meniscal repair. In the present study, we thoroughly reviewed the available evidence on meniscal repair surgery and summarized the main techniques that can be employed to enhance the biological healing potential of a meniscal lesion. Our aim was to provide an overview of the state of the art on meniscal repair and suggest the best techniques to reduce their failure rate.

Platelet-rich fibrin as an autologous biomaterial for bone regeneration: mechanisms, applications, optimization

Platelet-rich fibrin, a classical autologous-derived bioactive material, consists of a fibrin scaffold and its internal loading of growth factors, platelets, and leukocytes, with the gradual degradation of the fibrin scaffold and the slow release of physiological doses of growth factors. PRF promotes vascular regeneration, promotes the proliferation and migration of osteoblast-related cells such as mesenchymal cells, osteoblasts, and osteoclasts while having certain immunomodulatory and anti-bacterial effects. PRF has excellent osteogenic potential and has been widely used in the field of bone tissue engineering and dentistry. However, there are still some limitations of PRF, and the improvement of its biological properties is one of the most important issues to be solved. Therefore, it is often combined with bone tissue engineering scaffolds to enhance its mechanical properties and delay its degradation. In this paper, we present a systematic review of the development of platelet-rich derivatives, the structure and biological properties of PRF, osteogenic mechanisms, applications, and optimization to broaden their clinical applications and provide guidance for their clinical translation.

Augmentation of single tooth extraction socket with deficient buccal walls using bovine xenograft with platelet-rich fibrin membrane

BACKGROUND

Different techniques and materials such as bone grafts and bioactive agents have been used for alveolar ridge augmentation in extraction sockets with a defective wall, there is not a specific material or technique that has resulted in superior outcomes or prevented total bone loss.

OBJECTIVES

This clinical study aims to evaluate radiographically the effectiveness of using bovine xenograft with platelet-rich fibrin (PRF) membrane on vertical and horizontal alveolar ridge dimensional changes following tooth extraction that are complicated by buccal bone loss.

MATERIALS AND METHODS

This study was conducted in Egypt on fourteen patients with a single posterior tooth indicated for extraction. A preoperative cone-beam computed tomography (CBCT) scan confirmed more than 50% loss in buccal bone in each tooth. Extraction sockets were packed with minced PRF clots mixed with a bovine xenograft. Each extraction socket was sealed by PRF membranes. CBCT scans, performed before tooth extraction and after 6 months, were used to assess alveolar ridge changes both vertically and horizontally.

RESULTS

There was a significant gain in the buccal and middle of the extraction socket bone height, recording 86.01% (6.33 mm) and 206.45% (9.6 mm), respectively. There was an insignificant bone loss in the lingual bone height and width, recording - 8.49% (-1.06 mm) and - 13.39% (1.05 mm), respectively. The results also showed a non-significant decrease in alveolar bone density (-14.06%) between pre-operative bone present apical to the extraction socket and newly formed bone inside the socket.

CONCLUSIONS

Ridge preservation/augmentation techniques using a bone graft mixed with PRF and covered by PRF membranes in fresh extraction sockets complicated by the loss of buccal bone result in buccal bone augmentation and a reduction in horizontal and vertical ridge collapse after tooth extraction.

CLINICAL RELEVANCE

The bovine xenograft in conjunction with PRF can be used immediately after extraction for ridge preservation, providing adequate bone width and height for implant placement.

Alveolar Ridge Preservation with Autologous Platelet-Rich Fibrin (PRF): Case Reports and the Rationale

In dental implantology, alveolar ridge preservation (ARP) has emerged as a standard technique to address dimensional changes that affect alveolar ridge morphology following tooth loss. Various alternative graft materials, including xenografts, alloplasts, and allografts, have been effectively employed in fresh extraction sites for ARP. Current evidence suggests that these materials primarily serve as bio-scaffolds, which are slowly incorporated, thus necessitating a waiting period of at least 4-6 months before implant placement. Consequently, the ARP technique extends the overall duration of implant treatment by several months. Recently, the incorporation of a form of autologous platelet concentrate, known as platelet-rich fibrin (PRF), has been advocated in conjunction with ARP as a method of bioenhancement of soft- and hard-tissue healing and regeneration. PRF contains platelet-derived growth factors, hormones, and bioactive components like cytokines that have demonstrated the ability to stimulate angiogenesis and tissue regeneration throughout all phases of wound healing. Additionally, the concentration of leukocytes present in the PRF matrix plays a vital role in tissue healing and regeneration as part of the osteoimmune response. The reported advantages of incorporating autogenous PRF platelet concentrates during ARP encompass reduced healing time, improved angiogenesis and bone regeneration, socket sealing through the fibrin matrix, antibacterial properties, and decreased post-extraction pain and infection risk. Therefore, the objective of this paper is to review the existing evidence regarding the application of PRF in alveolar ridge preservation (ARP) following tooth extraction. Two clinical case studies are presented, wherein ARP was enhanced with PRF, followed by implant placement within a relatively short period of 8 weeks. These cases serve as further proof of concept for supporting the adjuvant use of PRF to enhance healing and accelerate implant placement after ARP.

The Effects of Platelet-Rich Fibrin in the Behavior of Mineralizing Cells Related to Bone Tissue Regeneration-A Scoping Review of In Vitro Evidence

Platelet-rich fibrin (PRF) is a second-generation blood concentrate that serves as an autologous approach for both soft and hard tissue regeneration. It provides a scaffold for cell interaction and promotes the local release of growth factors. PRF has been investigated as an alternative to bone tissue therapy, with the potential to expedite wound healing and bone regeneration, though the mechanisms involved are not yet fully understood. This review aims to explore the in vitro evidence of PRF's effects on the behavior of mineralizing cells related to bone tissue regeneration. A systematic electronic search was conducted up to August 2023, utilizing three databases: PubMed, Web of Science, and Scopus. A total of 76 studies were selected, which presented in vitro evidence of PRF's usefulness, either alone or in conjunction with other biomaterials, for bone tissue treatment. PRF membranes' influence on the proliferation, differentiation, and mineralization of bone cells is linked to the constant release of growth factors, resulting in changes in crucial markers of bone cell metabolism and behavior. This further reinforces their therapeutic potential in wound healing and bone regeneration. While there are some notable differences among the studies, the overall results suggest a positive effect of PRF on cell proliferation, differentiation, mineralization, and a reduction in inflammation. This points to its therapeutic potential in the field of regenerative medicine. Collectively, these findings may help enhance our understanding of how PRF impacts basic physiological processes in bone and mineralized tissue.

Radiographic and immuno-histochemical evaluation of root perforation repair using MTA with or without platelet-rich fibrin or concentrated growth factors as an internal matrix in dog's teeth: in vivo animal study

OBJECTIVES

To comparatively evaluate the in vivo outcome of MTA repair for contaminated and non-contaminated furcation perforations (FP) with or without PRF and CGF as a matrix in dogs' teeth.

METHODS

Ninety dog teeth were divided into five groups based on the iatrogenic FP repair approach after doing root canal treatment: negative control (without FP), positive control (FP without repair), MTA, MTA + PRF and MTA + CGF groups, where FP were repaired promptly in subdivision 1 (n = 10; non-contaminated) and after 4 weeks of oral contamination in subdivision 2 (n = 10;contaminated). After 3 months, the perforation site was assessed radiographically (vertical bone density), histologically (inflammatory cell count, epithelial proliferation, cementum and bone deposition) and immunohistochemically (OPN and TRAP antibodies localisation). Data collected were statistically analysed using SPSS software at a 0.05 significance level.

RESULTS

The MTA + PRF and MTA + CGF groups demonstrated significantly more bone formation, OPN immunolocalisation and fewer inflammatory cell counts than MTA group. MTA, MTA + PRF and MTA + CGF groups showed significantly favourable radiographic, histological and immunohistochemical healing features than the positive control, especially in non-contaminated subdivisions, that significantly showed better features than the contaminated subdivisions (P < 0.001).

CONCLUSION

The use CGF and PRF as a matrix beneath MTA in FP repair in dog's teeth is promising as it could increase hard and soft tissue regeneration in non-contaminated and contaminated perforations.

CLINICAL RELEVANCE

The repair of FP is challenging especially when associated with contaminated inter-radicular bone loss. Radiographic, histological and immunohistochemical comprehensive evaluation of the root and surrounding attachment apparatus response to different perforation repair protocols could give a predictable clinical outcome.

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

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

In vitro and in vivo assessment of decellularized platelet-rich fibrin-loaded strontium doped porous magnesium phosphate scaffolds in bone regeneration

The present work reports the effect of decellularized platelet-rich fibrin (dPRF) loaded strontium (Sr) doped porous magnesium phosphate (MgP) bioceramics on biocompatibility, biodegradability, and bone regeneration. Sustained release of growth factors from dPRF is a major objective here, which conformed to the availability of dPRF on the scaffold surface even after 7 days of in vitro degradation. dPRF-incorporated MgP scaffolds were implanted in the rabbit femoral bone defect and bone rejuvenation was confirmed by radiological examination, histological examination, fluorochrome labeling study, and micro-CT. μ-CT examination of the regained bone samples exhibited that invasion of mature bone in the pores of the MgP2Sr-dPRF sample was higher than the MgP2Sr which indicated better bone maturation capability of this composition. Quantifiable assessment using oxytetracycline labeling showed 73.55 ± 1.12% new osseous tissue regeneration for MgP2Sr-dPRF samples in contrast to 65.47 ± 1.16% for pure MgP2Sr samples, after 3 months of implantation. Histological analysis depicted the presence of abundant osteoblastic and osteoclastic cells in dPRF-loaded Sr-doped MgP samples as compared to other samples. Radiological studies also mimicked similar results in the MgP2Sr-dPRF group with intact periosteal lining and significant bridging callus formation. The present results indicated that dPRF-loaded Sr-doped magnesium phosphate bioceramics have good biocompatibility, bone-forming ability, and suitable biodegradability in bone regeneration.

Effect on Cellular Vitality In Vitro of Novel APRF-Chlorhexidine Treated Membranes

INTRODUCTION

Chlorhexidine (CHX) has been used for some time in clinical practice as a local antiseptic agent with excellent efficacy. The combination of CHX with APRF (Advanced-platelet rich fibrin) membrane has the potential to stimulate tissue regeneration and to provide a bactericidal effect. We hypothesize that this may reduce the rate of infections development and protect cell viability.

AIM

The aim of this study was two-fold-to create a stable APRF membrane treated with different concentrations of CHX (0.01% and 0.02%) and to monitor its effect on the viability of PDL cells in vitro. This benefits the introduction of a new protocol for APRF membrane production -CHX-PRF and enriches the available evidence on the effect of this antiseptic agent on PDL (Periodontal ligament) cells.

MATERIALS AND METHODS

APRF membranes were prepared by the addition of two concentrations (0.01% and 0.02%) of CHX. Membranes without the antiseptic were also prepared and used as control samples. PDL cells were cultivated on the membranes for 72 h. Cell number and vitality were examined by fluorescent cell viability assays.

RESULTS

Our results demonstrated that a concentration of 0.01% CHX allowed the production of a stable APRF membrane. This concentration slightly reduced the viability of PDL cells to 96.7%, but significantly decreased the average number of cells attached to the membrane-149 ± 16.5 cells/field compared to controls -336 ± 26.9 cells/field. APRF-CHX 0.02% membranes were unstable, indicating a dose-dependent cytotoxic effect of CHX.

CONCLUSIONS

The introduced novel protocol leads to the production of a new type of APRF membrane-CHX-PRF. The incorporation of an antiseptic into the APRF membrane can improve its bactericidal activity and might serve as an important step for the prevention of postoperative infections.

Preparation and In Vitro Osteogenic Evaluation of Biomimetic Hybrid Nanocomposite Scaffolds Based on Gelatin/Plasma Rich in Growth Factors (PRGF) and Lithium-Doped 45s5 Bioactive Glass Nanoparticles

Bone tissue engineering is an emerging technique for repairing large bone lesions. Biomimetic techniques expand the use of organic-inorganic spongy-like nanocomposite scaffolds and platelet concentrates. In this study, a biomimetic nanocomposite scaffold was prepared using lithium-doped bioactive-glass nanoparticles and gelatin/PRGF. First, sol-gel method was used to prepare bioactive-glass nanoparticles that contain 0, 1, 3, and 5%wt lithium. The lithium content was then optimized based on antibacterial and MTT testing. By freeze-drying, hybrid scaffolds comprising 5, 10, and 20% bioglass were made. On the scaffolds, human endometrial stem cells (hEnSCs) were cultured for adhesion (SEM), survival, and osteogenic differentiation. Alkaline phosphatase activity and osteopontin, osteocalcin, and Runx2 gene expression were measured. The effect of bioactive-glass nanoparticles and PRGF on nanocomposites' mechanical characteristics and glass-transition temperature (T _g) was also studied. An optimal lithium content in bioactive glass structure was found to be 3% wt. Nanoparticle SEM examination indicated grain deformation due to different sizes of lithium and sodium ions. Results showed up to 10% wt bioactive-glass and PRGF increased survival and cell adhesion. Also, Hybrid scaffolds revealed higher ALP-activity and OP, OC, and Runx2 gene expression. Furthermore, bioactive-glass has mainly increased ALP-activity and Runx2 expression, whereas PRGF increases the expression of OP and OC genes. Bioactive-glass increases scaffold modulus and T _g continuously. Hence, the presence of both bioactive-glass and nanocomposite scaffold improves the expression of osteogenic differentiation biomarkers. Subsequently, it seems that hybrid scaffolds based on biopolymers, Li-doped bioactive-glass, and platelet extracts can be a good strategy for bone repair.

Combination of Advanced Platelet-Rich Fibrin and Pentoxifylline/Tocopherol as a Novel Preventive Option in Osteoradionecrosis: A Case Report

Osteoradionecrosis (ORN) of the jaws is an uncommon complication of radiation therapy that seriously affects the oral and maxillofacial region. Management of ORN is intrinsically difficult and treatment effects are unpredictable. ORN can be treated with pentoxifylline/tocopherol and autologous platelet concentrates to promote wound healing. Furthermore, the low speed of relative centrifugal forces platelet-rich fibrin (PRF + ) has been shown high efficacy for ORN. A 72-year-old male patient with history of radiation treatment for squamous cell carcinoma in the left side of the tongue. Six years after the treatment, his upper right first molar tooth (no. 16) was surgically extracted due to persistent pain. A few months following the extraction, intraoral examination showed gingival inflammation, and pain when palpation around the edentulous area of tooth no. 16. Radiological examination revealed retained root of 16 with radiolucent area and horizontal bone loss around upper right second molar tooth (no. 17). Pentoxifylline and tocopherol were given for a week before the surgical operation and were continued for 8 weeks after the operation. Retained roots of teeth no. 16 and 17 were removed and the sockets were debrided, the advanced PRF+ (A-PRF + ) membranes were placed followed by primary wound closure. Following 2 weeks of treatment, the mucosa healed and progressed to complete mucosal coverage at 2 months with no pathological findings or ORN progression. At 6-month follow-up, clinical and cone-beam computed tomography (CBCT) revealed no pathology. Our case demonstrates that the combination of pentoxifylline/tocopherol and the A-PRF+ surgical approach can be useful for wound healing and prevention of ORN.

Quantitative assessment of platelet rich fibrin for the repair of extraction socket in a rat model

The present study evaluated the quantitative effects of platelet-rich fibrin (PRF) for the repair of extraction socket in Sprague Dawley (SD) rat model by assessing several key clinical parameters. Seventy two male SD rats were subjected to surgical extraction of the maxillary right incisor. Rats were randomly divided into four groups with eighteen rats in each group based on the treatment received: extraction socket without treatment of PRF was taken as control (group I). Extraction socket implanted with 0.1, 0.2, and 0.4 mL of PRF was taken as study groups (groups II, III, and IV). The obtained results demonstrated that, low dose of PRF efficiently enhanced the natural healing cascade. Whereas, high dose interfered with native tissue contribution and altered the natural healing process. The beneficial effects of quantity-based application of PRF may raise the possibility of a new approach as complementary therapy besides conventional treatment.

Arthroscopic Meniscal Repair With Second-Generation Platelet-Rich Fibrin Clot Augmentation

Meniscal tears are among the most common injuries in the knee, and partial as well as total meniscectomy has been advocated as the treatment for meniscal injury. Over the years, the role of the meniscus as a shock absorber, load transmitter, and secondary anterior stabilizer, along with its proprioceptive and lubrication role, has been well established, and meniscal repair is recommended, especially in younger individuals. Factors such as tear location, pattern, chronicity, size, and extent; repair technique; and patient age and habits can influence meniscal repair, and to enhance meniscal healing, a variety of augmentation techniques have been introduced. These include needling, trephination, synovial abrasion, and the use of adjuvants such as platelet-rich plasma, platelet clots, fibrin clots, bone marrow clots, and stem cells. A second-generation platelet derivative called "platelet-rich fibrin" (PRF) has predictable platelet, growth factor, and cell mediator concentrations without using any anticoagulants. We describe a reproducible and simple way to harvest PRF and create and use a PRF clot, along with detailed instructions on how to integrate the clot with a meniscal repair arthroscopically.

In Vitro and Ex Vivo Kinetic Release Profile of Growth Factors and Cytokines from Leucocyte- and Platelet-Rich Fibrin (L-PRF) Preparations

L-PRF is an autologous blood-derived biomaterial (ABDB) capable of releasing biologically active agents to promote healing. Little is known about its release profile of growth factors (GFs), cytokines, and MMPs. This study reported the in vitro and ex vivo release kinetics of GFs, cytokines, and MMPs from L-PRF at 6, 24, 72, and 168 h. The in vitro release rates of PDGF, TGF-β1, EGF, FGF-2, VEGF, and MMPs decreased over time with different rates, while those of IL-1β, IL-6, TNF-α, IL-8, and IL-10 were low at 6 h and then increased rapidly for up to 24 h and subsequently decreased. Of note, the release rates of the GFs followed first-order kinetics both in vitro and ex vivo. Higher rates of release were found ex vivo, suggesting that significant amounts of GFs were produced by the local cells within the wound. In addition, the half-life times of GFs locally produced in the wound, including PDGF-AA, PDGF-AB/BB, and VEGF, were significantly extended (p < 0.05). This work demonstrates that L-PRF can sustain the release of GFs and cytokines for up to 7 days, and it shows that the former can activate cells to produce additional mediators and amplify the communication network for optimizing the wound environment, thereby enhancing healing.

Osteoblast-like Cell Differentiation on 3D-Printed Scaffolds Using Various Concentrations of Tetra-Polymers

New bone formation starts from the initial reaction between a scaffold surface and the extracellular matrix. This research aimed to evaluate the effects of various amounts of calcium, phosphate, sodium, sulfur, and chloride ions on osteoblast-like cell differentiation using tetra-polymers of amorphous calcium phosphate (ACP), calcium sulfate hemihydrate (CSH), alginic acid, and hydroxypropyl methylcellulose. Moreover, 3D-printed scaffolds were fabricated to determine the ion distribution and cell differentiation. Various proportions of ACP/CSH were prepared in ratios of 0%, 13%, 15%, 18%, 20%, and 23%. SEM was used to observe the morphology, cell spreading, and ion complements. The scaffolds were also examined for calcium ion release. The mouse osteoblast-like cell line MC3T3-E1 was cultured to monitor the osteogenic differentiation, alkaline phosphatase (ALP) activity, total protein synthesis, osteocalcin expression (OCN), and calcium deposition. All 3D-printed scaffolds exhibited staggered filaments, except for the 0% group. The amounts of calcium, phosphate, sodium, and sulfur ions increased as the amounts of ACP/CSH increased. The 18%ACP/CSH group significantly exhibited the most ALP on days 7, 14, and 21, and the most OCN on days 14 and 21. Moreover, calcium deposition and mineralization showed the highest peak after 7 days. In conclusion, the 18%ACP/CSH group is capable of promoting osteoblast-like cell differentiation on 3D-printed scaffolds.

Optimization of Fibrin Scaffolds to Study Friction in Cultured Mesothelial Cells

To study the friction of cell monolayers avoiding damage due to stress concentration, cells can be cultured on fibrin gels, which have a structure and viscoelasticity similar to that of the extracellular matrix. In the present research, we studied different gel compositions and surface coatings in order to identify the best conditions to measure friction in vitro. We examined the adhesion and growth behavior of mesothelial cell line MET-5A on fibrin gels with different fibrinogen concentrations (15, 20, and 25 mg/mL) and with different adhesion coatings (5 μg/mL fibronectin, 10 μg/mL fibronectin, or 10 μg/mL fibronectin + 10 μg/mL collagen). We also investigated whether different substrates influenced the coefficient of friction and the ability of cells to stick to the gel during sliding. Finally, we studied the degradation rates of gels with and without cells. All substrates tested provided a suitable environment for the adherence and proliferation of mesothelial cells, and friction measurements did not cause significant cell damage or detachment. However, in gels with a lower fibrinogen concentration, cell viability was higher and cell detachment after friction measurement was lower. Fibrinolysis was negligible in all the substrates tested.

Applying extrusion-based 3D printing technique accelerates fabricating complex biphasic calcium phosphate-based scaffolds for bone tissue regeneration

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Biphasic calcium phosphates offer a chemically similar biomaterial to the natural bone, which can significantly accelerate bone formation and reconstruction.

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Robocasting is a suitable technique to produce porous scaffolds supporting cell viability, proliferation, and differentiation.

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This review discusses materials and methods utilized for BCP robocasting, considering recent advancements and existing challenges in using additives for bioink preparation.

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Commercialization and marketing approach, in-vitro and in-vivo evaluations, biologic responses, and post-processing steps are also investigated.

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Possible strategies and opportunities for the use of BCP toward injured bone regeneration along with clinical applications are discussed.

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The study proposes that BCP possesses an acceptable level of bone substituting, considering its challenges and struggles.

Background

Aim of review

Key scientific concepts of review

Comparison of quality of bone and insertion torque values of early implants placed at 6 and 8 weeks in sockets preserved with advanced platelet-rich fibrin: A randomized controlled trial

Aim

Successful functional and esthetic rehabilitation of edentulous jaws with implants depends on the optimal timing of placement, surgical protocol, materials used, cost-effectiveness, and satisfying patient needs. Increasing demand for shorter treatment times necessitates the immediate placement protocol. However, researchers have demonstrateda higher failure rate. A-PRF (Advanced platelet-rich fibrin) has exhibited accelerated bone regeneration potential. Early implant placement with a limited healing period, along with A-PRF, can be beneficial over conventional and immediate implant placement.

Settings and Design

This prospective randomized clinical trial aims to assess the outcome of early implant placement in sockets preserved using A-PRF at six weeks and eight weeks of post-extraction. Two groups of 10 participantseach were formed. All patients underwent atraumatic extraction and socket preservation using A-PRF.

Materials and Methods

A Partial-thickness pedicle graft was raised, and the extraction socket wasclosed. Implants wereplaced in at six and eight weeks of post-extraction in group A group B, respectively. The histomorphometric analysisassessedthe bone quality present at the timeof surgery. The insertion torque values were recorded during implant placement.

Statistical Analysis Used

The obtained data were statistically analyzed using parametric tests, namely independent T-test for intergroup comparison.

Results

T-test for torque values indicated a significantly higher torque value at eight weeks. The meanhistomorphometric value showeda significantly higher percentage of bone formation at eight weeks than at six weeks (P = 0.03).

Conclusion

Within the study's limitations, early implant placement in extraction sockets preserved with A-PRF had significantly higher insertion torque values and predictable bone at eight weeks compared to six weeks.

SB, Babu G, Vijayan V. Clinical Application of Platelet-Rich Fibrin in Pediatric Dentistry

Platelet-rich fibrin (PRF) is a fibrin matrix in which platelet cytokines, growth factors, and cells are trapped and may be released after a certain time and that can serve as a resorbable membrane. It can be obtained from blood with the help of a simple process. PRF is basically a concentrate of growth factors that promote wound healing and regeneration, which is used in various disciplines of dentistry to repair various lesions and regenerate dental and oral tissues. Although the use of PRF is well-documented, its use in pediatric dentistry remains unexplored, due to its restrictions and on account of the fact that it is a blood-derived product. PRF has been used globally to enhance tissue healing. This article provides an insight into the use of PRF in pediatric dentistry, its benefits, limitations, and recommendations.

Effectiveness of treating segmental bone defects with a synergistic co-delivery approach with platelet-rich fibrin and tricalcium phosphate

Several studies have applied tricalcium phosphate (TCP) or autografts in bone tissue engineering to enhance the clinical regeneration of bone. Unfortunately, there are several drawbacks related to the use of autografts, including a risk of infection, blood loss, limited quantities, and donor-site morbidities. Platelet-rich fibrin (PRF) is a natural extracellular matrix (ECM) biomaterial that possesses bioactive factors, which can generally be used in regenerative medicine. The goal of the present investigation was to develop osteoconductive TCP incorporated with bioactive PRF for bio-synergistic bone regeneration and examine the potential biological mechanisms and applications. Our in vitro results showed that PRF plus TCP had excellent biosafety and was favorable for initiating osteoblast cell attachment, slow release of bioactive factors, cell proliferation, cell migration, and ECM formation that potentially impacted bone repair. In a rabbit femoral segmental bone defect model, regeneration of bone was considerably augmented in defects locally implanted by PRF plus TCP according to radiographic and histologic examinations. Notably, the outcomes of this investigation suggest that the combination of PRF and TCP possesses novel synergistic and bio-inspired functions that facilitate bone regeneration.

Evaluation of the Use of Platelet-Rich Fibrin Xenologous Membranes Derived from Bubaline Blood in Canine Periodontal Defects

Periodontal disease is the most common oral disease in dogs. Platelet-rich fibrin (PRF) is widely utilized to facilitate soft and hard tissue healing and has been proposed in periodontal healing in small animal treatment. However, the quality and amount of autologous PRF is compromised in animals with systemic diseases. The present study aimed to evaluate the efficacy of xenologous bubaline blood-derived PRF (bPRF) on periodontal tissue healing in canine periodontal defects. Split-mouth design was employed in twenty dogs diagnosed with periodontal disease. The defects were divided randomly into two groups: the open-flap debridement (OFD)-treated group and the OFD with bPRF (OFD+bPRF) application group. Results demonstrated that gingival index and periodontal probing depth decreased significantly in the OFD+bPRF group compared with those treated with OFD alone. Application of bPRF in periodontal defects also promoted fibrous tissue formation, as confirmed by the marked increase in fibrosis score. bPRF application significantly increased COL1A1 and PDGFB mRNA levels at day 14 compared with the baseline. Taking this evidence together, bPRF provided a favorable therapeutic modality in canine periodontal defects. bPRF could be an alternative biomaterial for the treatment of periodontal defects in dogs.

The effectiveness of mineralized plasmatic matrix in the closure of alveolar clefts with volumetric assessment

Objectives: The purpose of this study is to assess the effectiveness of mineralized plasmatic matrix in the soft tissue closure of naso-alveolar fistula, to estimate the postoperative bone fill and volume of the graft placed in the alveolar cleft defect using cone-beam computed tomography (CBCT) at 3rd- month and 6th- month. Material and methods: 10 patients, in the age group of 15‑30 years were included in this study. They were diagnosed with unilateral cleft lip and alveolus defects with or without a cleft palate requiring late secondary alveolar bone grafting. Alveolar cleft defects were closed with mineralized plasmatic matrix (MPM), a combination of autogenous iliac bone graft and platelet rich plasma (PRP) and platelet rich fibrin (PRF). Results: The mean defect volume pre-operatively is 0.75 cm³ and at the end of 3rd-month postoperatively is 0.51 cm³ and at 6th-month postoperatively is 0.27 cm³. The average percentage of bone fill between preoperative (A) & 3th- month postoperatively (B) is 33.4% and between 3rd-month (B) and 6th-month post operatively (C) is 49.5%. Conclusions: Utilization of this new matrix (MPM), has shown to be effective in the closure of the cleft defect, oro-nasal fistula and also reduction in the volume of the residual cleft defect seen with sequential cone-beam computed tomography (CBCT) radiographs.

Platelet activation and antimicrobial activity of L-PRF: a preliminary study

Leukocyte and platelet rich fibrin (L-PRF) is one of the platelet concentrates used to support regeneration and healing process. Many studies showed possible immunological and antibacterial properties of L-PRF. We perform an in vitro study to analyze the effect of L-PRF on platelet activation, platelet-leukocytes interactions and antimicrobial activity, important components in the healing process. Molecular biomarkers related with platelet activation and platelet-leukocyte interactions were analyzed by means of flow cytometry when L-PRF exudate was added to whole blood platelets. L-PRF membrane was used to evaluate antimicrobial activity using Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853) and Candida albicans (ATCC 90028). Our experimental design allows to evaluate platelet activation and analyze molecular biomarkers of other immune cells and platelet-leukocyte interactions. From the results obtained we can conclude that L-PRF can be a valuable tool in healing process, efficient in activating platelets of whole blood and inhibiting microbial growth. In our opinion, the use of L-PRF exudate, in addition to L-PRF membrane, presents some advantages that have to be considered in clinical trials. Additional research on the characterization and quantification of cells and its products present in the L-PRF exudate, as well as on the temporal factor released. Also, further studies using strains isolated from clinical cases are needed.

Multi-walled carbon nanotube/hydroxyapatite nanocomposite with leukocyte- and platelet-rich fibrin for bone regeneration in sheep model

BACKGROUND

The aim of this study was to evaluate the effects of multi-walled carbon nanotubes/hydroxyapatite (MWCNT/HA) granules with or without leukocyte- and platelet-rich fibrin (L-PRF) on bone regeneration in cancellous bone of sheep model.

METHODS

Totally, 32 cylindrical holes were drilled in female sheep (n = 4) in the distal epiphysis and proximal metaphysis of right and left humerus and femur. The defects were randomly filled with (1) MWCNT/HA, (2) MWCNT/HA mixed with L-PRF, (3) L-PRF, and (4) left empty as control. After 8 weeks, defects were evaluated and compared radiographically using multi-slice computed tomographic (CT) scan and cone beam CT scans, histologically and histomorphometrically.

RESULTS

The results showed that there was no significant inflammation (> 10%) or foreign body reaction around the granules. The new lamellar bone was regenerated around the MWCNT/HA nanocomposite granules. Addition of L-PRF to MWCNT/HA demonstrated significantly improvement of new bone formation, about 27.40 ± 1.08%, in comparison with the L-PRF alone, about (12.16 ± 1.46%) (P < 0.01). Also, the rate of new bone formation was significantly greater with the use of MWCNT/HA granules (24.59 ± 1.54%) compared to the control (10.36 ± 1.17%) (P < 0.01).

CONCLUSION

Consequently, both biocompatibility and osteoconductivity of MWCNT/HA nanocomposite were demonstrated in the preclinical sheep model, and the use of L-PRF in combination with MWCNT/HA nanocomposite can improve bone regeneration.

Autologous Platelet-Rich Fibrin (PRF) as an Adjunct in the Management of Osteoradionecrosis and Medication-Related Osteonecrosis of Jaws. Case Series in A Single Centre

Osteoradionecrosis (ORN) of the jaws and medication-related osteonecrosis of the jaws (MRONJ) are uncommon but serious diseases affecting the oral and maxillofacial region with clinically similar appearance but distinct pathophysiology. Management of ORN and MRONJ is inherently challenging and the treatment outcomes are unpredictable. The use of autologous platelet concentrates (APCs) to promote hard and soft tissue healing is well described in the literature, and the efficacy of leucocyte and platelet-rich fibrin (L-PRF) has been well documented in a number of clinical studies. The aim of this study was to present our treatment strategy and the outcomes of incorporating L-PRF as a surgical adjunct in management of ORN and MRONJ in our centre. Methods: eight cases of ORN and MRONJ were treated with a combination of sequestrectomy and L-PRF as a surgical adjunct. Results: the overall success was 87.5%. Using L-PRF as an adjunct, we were able to predictably manage ORN and MRONJ without causing significant morbidity. Conclusion: our experience shows that L-PRF may be used as a valuable and cost-effective adjunct to surgical management of ORN and MRONJ. However, due to a limited number of patients, and a short period of review, the true effectiveness of the method is yet to be demonstrated in a longer follow-up study including a greater number of patients, besides the inclusion of a control group.

Possible Implications for Improved Osteogenesis? The Combination of Platelet-Rich Fibrin With Different Bone Substitute Materials

Bone substitute materials (BSM) are widely used in oral regeneration, but sufficient angiogenesis is crucial for osteogenesis. The combination of BSM with autologous thrombocyte concentrations such as platelet-rich fibrin (PRF) may represent a clinical approach to overcome this limitation. This study analyzes the early influence on osteoblast (HOB) in vitro. Here, four different BSM (allogeneic, alloplastic, and two of xenogeneic origin) were combined with PRF. After the incubation with osteoblasts for 24 h, cell viability, migration, and proliferation were assessed. Next, marker of proliferation, migration, and differentiation were evaluated on gene and protein levels in comparison to the native BSM and osteoblast alone. Addition of PRF increased viability for both the xenogeneic BSM (p = 0.0008, p = 0.032, respectively) in comparison to HOB and vs. native BSM (p = 0.008), and led to a tendency for increased cell proliferation and migration for all BSM (each p > 0.05). On gene basis, allogeneic and alloplastic BSM displayed a significantly increased RUNX2 expression (each p = 0.050). Expression of alkaline phosphatase for alloplastic (p = 0.050) and collagen-1 for xenogeneic BSM (p = 0.05) were significantly increased in combination with PRF. In addition, bone morphogenic protein was expressed significantly higher when xenogeneic material was combined with PRF in comparison to HOB alone (each p = 0.05). In summary, the combination of PRF with different BSM increases initial viability and may influence early proliferation and migration potential of osteoblast via RUNX2, alkaline phosphatase, collagen, and BMP2 especially in combination with alloplastic and xenogeneic BSM. Biofunctionalization of BSM using PRF might improve osteogenesis and extend the range of indications.

A hybrid scaffold of gelatin glycosaminoglycan matrix and fibrin as a carrier of human corneal fibroblast cells

A hybrid scaffold of gelatin-glycosaminoglycan matrix and fibrin (FGG) has been synthesized to improve the mechanical properties, degradation time and cell response of fibrin-like scaffolds. The FGG scaffold was fabricated by optimizing some properties of fibrin-only gel and gelatin-glycosaminoglycan (GG) scaffolds. Mechanical analysis of optimized fibrin-only gel showed the Young module and tensile strength of up to 72 and 121 KPa, respectively. Significantly, the nine-fold increase in the Young modulus and a seven-fold increase in tensile strength was observed when fibrin reinforced with GG scaffold. Additionally, the results demonstrated that the degradation time of fibrin was enhanced successfully up to 7 days which was much longer time compared to fibrin-only gel with 38 h of degradation time. More than 45% of FGG initial mass was preserved on day 7 in the presence of aprotinin. Human corneal fibroblast cells (HCFCs) were seeded on the FGG, fibrin-only gel and GG scaffolds for 5 days. The FGG scaffold showed excellent cell viability over 5 days, and the proliferation of HCFCs also increased significantly in comparison with fibrin-only gel and GG scaffolds. The FGG scaffold illustrates the great potential to use in which appropriate stability and mechanical properties are essential to tissue functionality.

Expression of Vascular Endothelial Growth Factor Using Platelet Rich Fibrin (PRF) and Nanohydroxyapatite (nano-HA) in Treatment of Periodontal Intra-Bony Defects - A Randomized Controlled Trial

The study aims to assess the concentration of vascular endothelial growth factors (VEGF) with platelet rich fibrin (PRF) biomaterial, while using it separately or in combination with nanohydroxyapatite (nano-HA) for treating intra-bony defects (IBDs) using radiographic evaluation (DBS-Win software). Sixty patients with IBD (one site/patient) and chronic periodontitis were recruited randomly to test either autologous PRF platelet concentrate, nano-HA bone graft, a combination of PRF platelet concentrate and nano-HA, or alone conventional open flap debridement (OFD). Recordings of clinical parameters including probing depth (PD), gingival index (GI), and clinical attachment level (CAL) were obtained at baseline and 6 months, post-operatively. One-way analysis of variance (ANOVA) was used to compare four groups; whereas, multiple comparisons were done through Tukey’s post hoc test. The results showed that CAL at baseline changed from 6.67 ± 1.23 to 4.5 ± 1.42 in group I, 6.6 ± 2.51 to 4.9 ± 1.48 in group II, 5.2 ± 2.17 to 3.1 ± 1.27 in group III, and 4.7 ± 2.22 to 3.7 ± 2.35 in group IV after 6 months. The most significant increase in bone density and fill was observed for IBD depth in group III that was recorded as 62.82 ± 24.6 and 2.31 ± 0.75 mm, respectively. VEGF concentrations were significantly increased at 3, 7, and 14 days in all groups. The use of PRF with nano-HA was successful regenerative periodontal therapy to manage periodontal IBDs, unlike using PRF alone. Increase in VEGF concentrations in all group confirmed its role in angiogenesis and osteogenesis in the early stages of bone defect healing.

Platelet-rich plasma and regenerative dentistry

Regenerative dentistry is an emerging field of medicine involving stem cell technology, tissue engineering and dental science. It exploits biological mechanisms to regenerate damaged oral tissues and restore their functions. Platelet‐rich plasma (PRP) is a biological product that is defined as the portion of plasma fraction of autologous blood with a platelet concentration above that of the original whole blood. A super‐mixture of key cytokines and growth factors is present in platelet granules. Thus, the application of PRP has gained unprecedented attention in regenerative medicine. The rationale underlies the utilization of PRP is that it acts as a biomaterial to deliver critical growth factors and cytokines from platelet granules to the targeted area, thus promoting regeneration in a variety of tissues. Based on enhanced understanding of cell signalling and growth factor biology, researchers have begun to use PRP treatment as a novel method to regenerate damaged tissues, including liver, bone, cartilage, tendon and dental pulp. To enable better understanding of the regenerative effects of PRP in dentistry, this review describes different methods of preparation and application of this biological product, and provides detailed explanations of the controversies and future prospects related to the use of PRP in dental regenerative medicine.

The Effects of Leukocyte-Platelet Rich Fibrin (L-PRF) on Suppression of the Expressions of the Pro-Inflammatory Cytokines, and Proliferation of Schwann Cell, and Neurotrophic Factors

This study evaluates the use of L-PRF as an autologous scaffold in nerve regeneration, and Schwann cells (SCs) proliferation and secretion of neurotrophic factors and its anti-inflammatory effect on SC Porphyromonas Gingivalis-Lipopolysaccharide (PG-LPS)-induced inflammatory responses in vitro. SEM was done to investigate various features of L-PRF. L-PRF-extracts was used to investigate the release of growth factors and treatment of SCs line. ELISA was applied to examine the release of IGF-1. The proliferative effect of L-PRF on SCs was assessed with CCK-8 assay. The effect of L-PRF on the mRNA and protein expression of SC neurotrophic factors were analyzed by RT-qPCR and ELISA. CCK-8 assay and RT-qPCR were used to determine the required concentration and the action time of PG-LPS before the anti-inflammatory effect of L-PRF was determined by measuring the changes in IL-1β, IL-6, and TNF-a with RT-qPCR and ELISA. There are different features in L-PRF. Fourteen days was sufficient to release adequate GF. The mRNA expressions of the pro-inflammatory cytokines were notably raised by PG-LPS in 3-hours treatment. L-PRF can increase SC proliferation, neurotrophic factors secretion, and suppress SC PG-LPS-induced inflammatory responses in vitro. L-PRF has the potential as an autologous biological additive for peripheral nerve regeneration in the event of nerve inflammation and injuries.

Effect of platelet-rich fibrin on cell proliferation, migration, differentiation, inflammation, and osteoclastogenesis: a systematic review of in vitro studies

Objective

To systematically assess the effects of platelet-rich fibrin (PRF) on in vitro cellular behavior.

Methods

A systematic electronic search using MEDLINE database was performed. In vitro studies using PRF were considered and articles published up to June 31, 2018 were screened. Eligible studies were selected based on the use of human PRF.

Results

In total, 1746 titles were identified with the search terms, from these 37 met the inclusion criteria and were chosen for data extraction. In addition, 16 new studies, mainly published in 2019, were also included in the analysis resulting in 53 studies. No meta-analysis could be performed due to the heterogeneity of study designs. Included studies show that PRF enhances proliferation, migration, adhesion, and osteogenic differentiation on a variety of cell types along with cell signaling activation. Furthermore, PRF reduces inflammation, suppresses osteoclastogenesis, and increases the expression of various growth factors in mesenchymal cells.

Summary and conclusions

Despite some notable differences of the studies, the overall findings suggest a positive effect of PRF on cell proliferation, migration, adhesion, differentiation, and inflammation pointing towards a therapeutic potential in regenerative dentistry.

Clinical relevance

PRF serves as a reservoir of bioactive molecules to support wound healing and bone regeneration. Although the cellular mechanisms by which PRF supports the clinical outcomes remain unclear, in vitro research provides possible explanations. This systematic review aims to provide an update of the existing research on how PRF affects basic physiological processes in vitro. The overall findings suggest that PRF induces cell proliferation, migration, adhesion, and differentiation along with possessing anti-inflammatory properties further supporting its therapeutic potential in wound healing and bone regeneration.

Use of Platelet-Rich Plasma and Platelet-Rich Fibrin in Dentistry and Oral Surgery: Introduction and Review of the Literature

Platelet concentrates, mostly represented by platelet-rich plasma and platelet-rich fibrin, have gained significant interest in various medical and oral disciplines because of their potential to stimulate and boost regeneration of hard and soft tissues. Prepared from the patient’s own blood, they have been tested and used in various different surgical fields including oral and maxillofacial surgery. The effects of these biomaterials are described to be a result of the large concentration of platelets which contain a wide range of growth factors. The aim of this article is to introduce the principle and function of these platelet concentrates, to review their preparation, and to provide a comprehensive examination of the published oral and maxillofacial literature on this subject.

Use of platelet-rich fibrin and surgical approach for combined treatment of osteoradionecrosis: a case report

Osteoradionecrosis (ORN) is a complication of radiation therapy for which several treatment options have been reported. The use of platelet‐rich fibrin (PRF), a second-generation platelet concentrate, has been promoted in refractory wounds. A 53-year-old man underwent concurrent chemoradiotherapy for squamous cell carcinoma in the right side of the tongue. Subsequently, he exhibited pus discharge around the right maxillary first molar. Intraoral examination showed mobility and probing depths of >10 mm in teeth 15 and 16. Computed tomography revealed poorly defined osteolytic changes in teeth 15 to 17, indicative of oroantral fistula. Teeth 15 to 17 were extracted and the socket was debrided. Primary closure was achieved after PRF dressing. The wound healed within 2 weeks. The patient returned because of spontaneous loss of tooth 46 and numbness over the right lower lip. Pus was present in premolar areas and in the tooth 46 socket. Radiographic examination showed moth-eaten destruction in right mandibular teeth and better trabecular quality in the right maxilla. A provisional diagnosis of ORN was made. Debridement and primary closure after PRF dressing were performed. The mucosa healed within 3 weeks. Our findings suggest that PRF combined with a surgical approach might be useful for treatment of ORN.

Evaluation of Vestibular Bone Thickness in Class I Malocclusion Treatment With Corticotomy-Assisted Rapid Orthodontics

BACKGROUND

Corticotomy-assisted rapid orthodontics is a widely used method for speeding up conventional orthodontics. This study (i) evaluates the effects of corticotomy alone, corticotomy combined with bone graft, and corticotomy with platelet-rich fibrin (PRF) on vestibular alveolar bone thickness in patients with class I malocclusion; (ii) compares the treatment time with a conventional orthodontic therapy group, and (iii) investigates the periodontal health of patients who have undergone corticotomy-assisted rapid orthodontics.

METHODS

The patients were divided into 3 groups: Group 1 (n = 10) underwent corticotomy alone; Group 2 (n = 10) underwent corticotomy combined with bone graft, and Group 3 (n = 10) underwent corticotomy combined with PRF. In the following stage, vestibular alveolar bone thicknesses were evaluated using 3-dimensional cone-beam computed tomography images.

RESULTS

The findings showed that Group 2 achieved a more significant augmentation of the vestibular alveolar bone than Groups 1 and 3 (P = 0.001, P = 0.003), while corticotomy-assisted rapid orthodontics decreased treatment times. Sufficient alveolar bone thickness and preservation of the periodontal health were achieved when the corticotomy procedure was either combined with a bone graft or with PRF in the Class-I malocclusion patients.

CONCLUSION

Bone grafts provided better bone thickness at the buccal surface of the anterior teeth of the mandible and maxilla, whereas the thickness of the keratinized gingiva was better with PRF.

Leukocyte- and platelet-rich fibrin as graft material improves microRNA-21 expression and decreases oxidative stress in the calvarial defects of diabetic rabbits

OBJECTIVE

Leukocyte- and platelet-rich fibrin (L-PRF) represents a natural, low-cost product which may promote tissue healing by mechanisms not fully elucidated. Diabetes mellitus (DM) disrupts bone healing by inducing inflammation and oxidative stress (OS), mechanisms regulated by microRNAs (miRs). The aim of the present study was to investigate the microRNA-21 (miR-21) involvement in diabetic bone regeneration using L-PRF alone or in combination with a standard grafting material.

DESIGN

After the induction of diabetes (alloxan 100 mg/kg), four cranial osteotomies were made in diabetic (n = 12) and non-diabetic (n = 12) rabbits: one was left empty and the remaining three were grafted with L-PRF, bovine hydroxyapatite (Bio-Oss^®) and L-PRF + Bio-Oss®. Two and eight weeks postoperatively, the samples were harvested for miR-21 expression (Real-time RT-PCR) and enzyme-linked immunosorbent assay analyses.

RESULTS

Diabetic rabbits showed decreased miR-21 and matrix metalloproteinase-9 (MMP-9) protein expression while increased malondialdehyde (MDA) levels two weeks postoperatively; however, there were no significant differences in miR-21 and MMP-9 levels between diabetic and non-diabetic rabbits in samples taken eight weeks postoperatively. Application of L-PRF and L-PRF + Bio-Oss^® improved miR-21 and MMP-9 and decreased MDA levels while Bio-Oss® alone enhanced superoxide dismutase (SOD) activity levels in diabetic rabbits.

CONCLUSION

L-PRF alone or in combination with bovine hydroxyapatite as bone graft could be beneficial in DM since it seems to improve inflammation-modulatory miR-21 expression and decreases oxidative stress.

Abundant proteins in platelet-rich fibrin and their potential contribution to wound healing: An explorative proteomics study and review of the literature

Background/purpose

It is well-known that diverse types of blood proteins contribute to healing process via different mechanisms. Presence and potential involvements of blood-derived abundant proteins in the platelet-rich fibrin (PRF) to its regenerative capacity have not been sufficiently emphasized in the literature. The aim of this paper was to analyze the abundant proteome content of PRF and summarize previously reported effects of identified proteins on wound healing via a literature review.

Materials and methods

The PRF samples obtained from non-smoking, systemically healthy volunteers were subjected to 2D gel electrophoresis after extracting the proteins from fibrin matrices. All matching spots were excised from the gels and identified by MALDI TOF/TOF MS/MS analysis. A literature review was conducted to reveal possible contributions of identified proteins to wound healing.

Results

Totally, thirty-five blood proteins were commonly identified among all studied samples. These proteins included serine protease inhibitors, such as alpha-1-antitrypsin, alpha-1-antichymotrypsin, alpha-1-acid glycoprotein, inter-alpha-trypsin-inhibitor, protease C1 inhibitor, and complement proteins. In addition, abundant presence of immunoglobulin G was observed. The abundance of albumin, haptoglobin, ceruloplasmin vitronectin, fetuin-A, ficolin-3 and transthyretin was also detected.

Conclusion

The results of this study indicated that PRF abundantly contains blood-origin actors which were previously reported for their direct contribution to wound healing. Further studies exploring the protein content of PRF are needed to reveal its undisclosed potential roles in the healing process.

Injectable platelet rich fibrin: cell content, morphological, and protein characterization

OBJECTIVES

The aim of the present study was to evaluate the blood cell content, morphological aspects, gene expression of type I collagen, and release of growth factors on an injectable platelet rich fibrin (i-PRF).

MATERIALS AND METHODS

Blood samples were collected from 15 volunteers to prepare i-PRF samples. Peripheral blood was used as a control group. Blood clot and i-PRF samples were cultured for 10 days. The supernatant of the samples was collected for ELISA immunoassay quantification of PDGF and VEGF growth factors over periods of 1, 8, 24, 72, and 240 h. I-PRF and blood clot samples were biologically characterized using histological and immunohistochemistry analysis for IL-10, osteocalcin, and TGF-β. Scanning electron microscopy (SEM) was used to inspect the fibrin network and distribution of blood platelets and leukocytes. Reverse transcriptase polymerase chain reaction (RT-PCR) method was used to evaluate gene expression for type I collagen.

RESULTS

A higher concentration of platelets and lymphocytes was recorded in i-PRF than in peripheral blood (p < 0.05). The release of VEGF was higher in blood clot samples (1933 ± 704) than that for i-PRF (852 ± 376; p < 0.001). Immunohistochemistry showed upregulation of TGF-B, IL-10, and osteocalcin in the i-PRF group. RT-PCR showed increased type I collagen gene expression in i-PRF (p < 0.05). SEM images revealed agglomeration of platelets in some regions, while a fibrin networking was noticeable in the entire i-PRF sample.

CONCLUSIONS

Injectable platelet rich fibrin becomes a good approach for soft and mineralized tissue healing considering the formation of a three-dimensional fibrin network embedding platelets, leukocytes, type I collagen, osteocalcin, and growth factors. Indeed, the injectable platelet rich fibrin can be indicated in several medical applications regarding bioactivity, simplied technique, and flowable mixing with other biomaterials.

CLINICAL RELEVANCE

Morphological, cell, and protein characterization of platelet rich fibrin provides a better understanding of the clinical effects and improvement of clinical guidelines for several medical applications. Once well physicochemical and biologically characterized, the use of an injectable platelet rich fibrin can be extended to other applications in the field of orthopedics, periodontics, and implant dentistry on the repairing process of both soft and mineralized tissues.

Nano-biphasic calcium phosphate/polyvinyl alcohol composites with enhanced bioactivity for bone repair via low-temperature three-dimensional printing and loading with platelet-rich fibrin

Background and aim

As a newly emerging three-dimensional (3D) printing technology, low-temperature robocasting can be used to fabricate geometrically complex ceramic scaffolds at low temperatures. Here, we aimed to fabricate 3D printed ceramic scaffolds composed of nano-biphasic calcium phosphate (BCP), polyvinyl alcohol (PVA), and platelet-rich fibrin (PRF) at a low temperature without the addition of toxic chemicals.

Methods

Corresponding nonprinted scaffolds were prepared using a freeze-drying method. Compared with the nonprinted scaffolds, the printed scaffolds had specific shapes and well-connected internal structures.

Results

The incorporation of PRF enabled both the sustained release of bioactive factors from the scaffolds and improved biocompatibility and biological activity toward bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Additionally, the printed BCP/PVA/PRF scaffolds promoted significantly better BMSC adhesion, proliferation, and osteogenic differentiation in vitro than the printed BCP/PVA scaffolds. In vivo, the printed BCP/PVA/PRF scaffolds induced a greater extent of appropriate bone formation than the printed BCP/PVA scaffolds and nonprinted scaffolds in a critical-size segmental bone defect model in rabbits.

Conclusion

These experiments indicate that low-temperature robocasting could potentially be used to fabricate 3D printed BCP/PVA/PRF scaffolds with desired shapes and internal structures and incorporated bioactive factors to enhance the repair of segmental bone defects.

Proliferation and differentiation of stem cells in contact with eluate from fibrin-rich plasma membrane

OBJECTIVE

To evaluate the ability of the eluate from fibrin-rich plasma (FRP) membrane to induce proliferation and differentiation of isolated human adipose-derived stem cells (ASCs) into chondrocytes.

METHOD

FRP membranes were obtained by centrifugation of peripheral blood from two healthy donors, cut, and maintained in culture plate wells for 48 h to prepare the fibrin eluate. The SCATh were isolated from adipose tissue by collagenase digestion solution, and expanded in vitro. Cells were expanded and treated with DMEM-F12 culture, a commercial media for chondrogenic differentiation, and eluate from FRP membrane for three days, and labeled with BrdU for quantitative assessment of cell proliferation using the High-Content Operetta® imaging system. For the chondrogenic differentiation assay, the SCATh were grown in micromass for 21 days and stained with toluidine blue and aggrecan for qualitative evaluation by light microscopy. The statistical analysis was performed using ANOVA and Tukey's test.

RESULTS

There was a greater proliferation of cells treated with the eluate from FRP membrane compared to the other two treatments, where the ANOVA test showed significance (p < 0.001). The differentiation into chondrocytes was visualized by the presence of mucopolysaccharide in the matrix of the cells marked in blue toluidine and aggrecan.

CONCLUSIONS

Treatment with eluate from FRP membrane stimulated cell proliferation and induced differentiation of the stem cells into chondrocytes, suggesting a potential application of FRP membranes in hyaline cartilage regeneration therapies.

The effect of platelet-rich fibrin on autologous osteochondral transplantation: An in vivo porcine model

BACKGROUND

This work aimed to evaluate the efficacy of cartilage transplantation to the medial femoral condyle±platelet-rich fibrin (PRF) augmentation in a porcine model. The hypothesis of the study was that PRF may act as a bioactive cell scaffold to fill defects and enhance cartilage regeneration.

METHODS

Thirty-two knees of 16 miniature pigs were randomly assigned to four groups. The critical-size osteochondral defects (8x5mm) in femoral condyle of both knees were treated with one of the following: group 1－untreated controls; group 2－cartilage fragments alone; group 3－PRF alone; group 4－PRFT+cartilage fragments. After completion of the surgical implantation, the periosteal patch harvested from the proximal tibia was sutured onto the cartilage of the medial condyle to cover the implanted defects. Animals were sacrificed at six months after treatment. The regenerated cartilages were assessed by gross inspection and histological examination.

RESULTS

The best results were obtained with the repair tissue being hyaline-like cartilage (group 4). The grading score of histological evaluation demonstrated that group 4 had better matrix, cell distribution and cartilage mineralization than group 2 and group 3. PRF showed a positive effect on the cartilage repair; the procedure was more effective when PRF was combined with autologous chondrocytes.

CONCLUSIONS

This approach may provide a successfully employed technique to target cartilage defects in vivo. Larger groups and longer periods of study may provide more definitive and meaningful support for using this therapeutic approach as a new way of cartilage regeneration.

Large Periapical or Cystic Lesions in Association with Roots Having Open Apices Managed Nonsurgically Using 1-step Apexification Based on Platelet-rich Fibrin Matrix and Biodentine Apical Barrier: A Case Series

Teeth having open apices in the absence of a natural apical constriction pose several challenges during conventional endodontic treatment, especially when establishing an apical seal. Treatment is further challenging when these teeth are associated with large periapical or cystic lesions having resulted in expansion and/or thinning of adjacent cortical plates. Although surgical intervention is commonly adopted in the management of such cases, a conservative treatment option offering equally good prognosis is always desirable. This case series describes 3 cases: a 39-year-old woman, a 45-year-old woman, and a 15-year-old boy having teeth with concomitant open apices and large periapical/cystic lesions managed conservatively by (1) following a strict intracanal disinfection protocol, (2) intracanal aspiration with digital decompression of associated swelling, and (3) 1-step apexification for closure of the root apex by placing a preliminary barrier of platelet-rich fibrin (PRF) and a secondary barrier of Biodentine (Septodont, Saint-Maur-des-Fossés, France). In all 3 cases, the treatment outcomes, both clinical and radiographic, were highly satisfactory. PRF and Biodentine collectively rendered an apical plug that proved to be a suitable alternative to commonly used mineral trioxide aggregate in 1-step apexification. Biodentine provides good interfacial adhesion and sealing with dentin attributed to its property of hydroxyapatite crystal deposition at the material-dentin interface. Also, because of its bioactivity, it likely promotes the conversion of adjacent PRF into a calcific barrier, thus reinforcing the apical seal. Additionally, host-modulating responses of PRF contribute in expediting the healing process. Reasonable osseous healing in the periapex could be appreciated as early as 3 months in all patients. The rapidity with which healing occurred may have been an incidental finding but definitely draws attention.

Adjunctive Effect of Autologus Platelet-Rich Fibrin to Barrier Membrane in the Treatment of Periodontal Intrabony Defects

BACKGROUND AND AIM

Autologous platelet-rich fibrin (PRF) and barrier membranes in the treatment of intrabony defects in chronic periodontitis patients have shown significant clinical benefits. This study evaluates the additive effect of autologous PRF in combination with a barrier membrane versus the use of barrier membrane alone for the treatment of intrabony defects in chronic periodontitis patients.

METHODS

A randomized split-mouth design was used. Sixteen patients with 32 paired intrabony defects were included. In each patient 1 defect was treated using a resorbable collagen membrane along with PRF (test group) and the other defect by guided tissue regeneration alone (control group). The following clinical parameters were measured at baseline and after 9 months: plaque index, modified sulcus bleeding index, probing pocket depth, clinical attachment level, and gingival marginal level. The radiographic defect depth was also assessed at baseline and after 9 months.

RESULTS

Test group showed a statistically significant improvement for probing depth (P = 0.002), clinical attachment level (P = 0.001), and radiographic defect depth (P < 0.001) after 9 months as compared with the control sites. Radiographic defect depth reduction was 58.19 ± 13.24% in the test group as compared with 24.86 ± 9.94% reduction in the control group.

CONCLUSIONS

The adjunctive use of PRF in combination with barrier membrane is more effective in the treatment of intrabony defects in chronic periodontitis as compared with barrier membrane alone.