OBJECTIVE: Diabetic foot ulcer (DFU) is one of the most serious complications of diabetes. Leukocyte- and platelet-rich fibrin (L-PRF) is a second-generation autologous platelet-rich plasma. This study aims to investigate the clinical effects of L-PRF in patients with diabetes in real clinical practice.
METHODS: Patients with DFU who received L-PRF treatment and standard of care (SOC) from 2018 to 2019 in Tongji Hospital were enrolled. The clinical information including patient characteristics, wound evaluation (area, severity, infection, blood supply), SOC of DFU, and images of ulcers was retrospectively extracted and analyzed. L-PRF treatment was performed every 7±2 days until the ulcer exhibited complete epithelialization or an overall percent volume reduction (PVR) greater than 80%. Therapeutic effectiveness, including overall PVR and the overall and weekly healing rates, was evaluated.
RESULTS: Totally, 26 patients with DFU were enrolled, and they had an ulcer duration of 47.0 (35.0, 72.3) days. The severity and infection of ulcers varied, as indicated by the Site, Ischemia, Neuropathy, Bacterial Infection, and Depth (SINBAD) scores of 2-6, Wagner grades of 1-4, and the Perfusion, Extent, Depth, Infection and Sensation (PEDIS) scores of 2-4. The initial ulcer volume before L-PRF treatment was 4.94 (1.50, 13.83) cm3, and the final ulcer volume was 0.35 (0.03, 1.76) cm3. The median number of L-PRF doses was 3 (2, 5). A total of 11 patients achieved complete epithelialization after the fifth week of treatment, and 19 patients achieved at least an 80% volume reduction after the seventh week. The overall wound-healing rate was 1.47 (0.63, 3.29) cm3/week, and the healing rate was faster in the first 2 weeks than in the remaining weeks. Concurrent treatment did not change the percentage of complete epithelialization or healing rate.
CONCLUSIONS: Adding L-PRF to SOC significantly improved wound healing in patients with DFU independent of the ankle brachial index, SINBAD score, or Wagner grade, indicating that this method is appropriate for DFU treatment under different clinical conditions.

Leukocyte and Platelet-Rich Fibrin (L-PRF) is part of the second generation of platelet-concentrates. L-PRF derived from nonsmokers has been used in surgical procedures, with its beneficial effects in wound healing being proven to stimulate biological activities such as cell proliferation, angiogenesis, and differentiation. Cigarette smoking exerts detrimental effects on tissue healing and is associated with post-surgical complications; however, evidence about the biological effects of L-PRF derived from smokers is limited. This study evaluated the impact of L-PRF secretome (LPRFS) derived from smokers and nonsmokers on angiogenesis and osteoblast differentiation. LPRFS was obtained by submerging L-PRF membranes derived from smokers or nonsmokers in culture media and was used to treat endothelial cells (HUVEC) or SaOs-2 cells. Angiogenesis was evaluated by tubule formation assay, while osteoblast differentiation was observed by alkaline phosphatase and osterix protein levels, as well as in vitro mineralization. LPRFS treatments increased angiogenesis, alkaline phosphatase, and osterix levels. Treatment with 50% of LPRFS derived from smokers and nonsmokers in the presence of osteogenic factors stimulates in vitro mineralization significantly. Nevertheless, differences between LPRFS derived from smokers and nonsmokers were not found. Both LPRFS stimulated angiogenesis and osteoblast differentiation in vitro; however, clinical studies are required to determine the beneficial effect of LPRFS in smokers.

OBJECTIVE: To investigate, through a network meta-analysis, the effectiveness of blood concentrates in reducing pain perception, trismus, and edema after mandibular third molar extraction.
METHODS: An electronic search was performed in nine databases to locate randomized clinical trials comparing blood concentrate use after mandibular third molar extraction. Two authors selected and extracted the data independently. The individual risk of bias in the studies was assessed with the RoB v2.0 tool. A network meta-analysis compared postoperative pain and trismus scores after applying different blood concentrates, using the mean difference (MD) as an effect estimate. The GRADE approach assessed the certainty of evidence.
RESULTS: Thirty-one randomized clinical trials were included in the review and 18 in the meta-analysis. Leukocyte- and platelet-rich fibrin (L-PRF) was the most used blood concentrate, followed by platelet-rich plasma (PRP). The network meta-analysis, depending on the analyzed period, evaluated up to 1240 surgeries. Among the analyzed blood concentrates, advanced platelet-rich fibrin (A-PRF) performed better among the analyzed blood concentrates, decreasing postoperative pain in 1, 2, 3, and 7 days and reducing trismus up to the inflammatory peak compared to blood clots. Only two studies had a low risk of bias.
CONCLUSIONS: Based on very low certainty of evidence, using concentrates seemed efficient compared to blood clots in reducing pain and trismus after mandibular third molar surgeries. A-PRF decreased postoperative pain throughout the evaluated time and trismus during the acute inflammatory peak.
CONCLUSIONS: A-PRF after mandibular third molar extractions performed better among the analyzed blood concentrates and seemed efficient in improving postoperative quality by decreasing inflammatory signs and symptoms.

In the past decades, personalized regenerative medicine has gained increased attention. Autologous platelet concentrates (APCs) such as PRP, PRGF, and L-PRF, all serving as a source of a large variety of cells and growth factors that participate in hard and soft tissue healing and regeneration, could play a significant role in regenerative periodontal procedures. This narrative review evaluated the relative impact of APCs in alveolar ridge preservation, sinus floor augmentation, and the regeneration of bony craters around teeth, both as a single substitute or in combination with a xenograft. L-PRF has a significant beneficial effect on alveolar ridge preservation (bone quality). The data for PRGF are less convincing, and PRP is controversial. L-PRF can successfully be used as a single substitute during transcrestal (≥3.5 mm bone gain) as well as 1-stage lateral window sinus floor elevation (>5 mm bone gain). For PRGF and especially PRP the data are very scarce. In the treatment of bony craters around teeth, during open flap debridement, L-PRF as a single substitute showed significant adjunctive benefits (e.g., >PPD reduction, >CAL gain, >crater depth reduction). The data for PRP and PRGF were non-conclusive. Adding PRP or L-PRF to a xenograft during OFD resulted in additional improvements (>PPD reduction, >CAL gain, >bone fill), for PRGF no data were found. Autologous platelet concentrates demonstrated to enhance bone and soft tissue healing in periodontal regenerative procedures. The data for L-PRF were most convincing. L-PRF also has the advantage of a greater simplicity of production, and its 100% autologous character.

Leukocyte- and Platelet-Rich Fibrin (L-PRF) is a second-generation platelet concentrate that is prepared directly from the patient\'s own blood. It is widely used in the field of regenerative medicine, and to better understand its clinical applicability we aimed to further explore the biological properties and effects of L-PRF on cells from the central and peripheral nervous system. To this end, L-PRF was prepared from healthy human donors, and confocal, transmission, and scanning electron microscopy as well as secretome analysis were performed on these clots. In addition, functional assays were completed to determine the effect of L-PRF on neural stem cells (NSCs), primary cortical neurons (pCNs), and peripheral dorsal root ganglion (DRG) neurons. We observed that L-PRF consists of a dense but porous fibrin network, containing leukocytes and aggregates of activated platelets that are distributed throughout the clot. Antibody array and ELISA confirmed that it is a reservoir for a plethora of growth factors. Key molecules that are known to have an effect on neuronal cell functions such as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) were slowly released over time from the clots. Next, we found that the L-PRF secretome had no significant effect on the proliferative and metabolic activity of NSCs, but it did act as a chemoattractant and improved the migration of these CNS-derived stem cells. More importantly, L-PRF growth factors had a detrimental effect on the survival of pCNs, and consequently, also interfered with their neurite outgrowth. In contrast, we found a positive effect on peripheral DRG neurons, and L-PRF growth factors improved their survival and significantly stimulated the outgrowth and branching of their neurites. Taken together, our study demonstrates the positive effects of the L-PRF secretome on peripheral neurons and supports its use in regenerative medicine but care should be taken when using it for CNS applications.

Secretomes of mesenchymal stromal cells (MSCs) are emerging as a novel growth factor (GF)-based strategy for periodontal and bone regeneration. The objective of this study was to compare the secretome of human bone marrow MSC (BMSC) to that of leukocyte- and platelet-rich fibrin (L-PRF), an established GF-based therapy, in the context of wound healing and regeneration. Conditioned media from human BMSCs (BMSC-CM) and L-PRF (LPRF-CM) were subjected to quantitative proteomic analysis using liquid chromatography with tandem mass spectrometry. Global profiles, gene ontology (GO) categories, differentially expressed proteins (DEPs), and gene set enrichment (GSEA) were identified using bioinformatic methods. Concentrations of selected proteins were determined using a multiplex immunoassay. Among the proteins identified in BMSC-CM (2157 proteins) and LPRF-CM (1420 proteins), 1283 proteins were common. GO analysis revealed similarities between the groups in terms of biological processes (cellular organization, protein metabolism) and molecular functions (cellular/protein-binding). Notably, more DEPs were identified in BMSC-CM (n = 550) compared to LPRF-CM (n = 118); these included several key GF, cytokines, and extracellular matrix (ECM) proteins involved in wound healing. GSEA revealed enrichment of ECM (especially bone ECM)-related processes in BMSC-CM and immune-related processes in LPRF-CM. Similar trends for intergroup differences in protein detection were observed in the multiplex analysis. Thus, the secretome of BMSC is enriched for proteins/processes relevant for periodontal and bone regeneration. The in vivo efficacy of this therapy should be evaluated in future studies.

BACKGROUND: Recent advances in endoscopic endonasal transsphenoidal approaches (EETA) for skull base lesions have resulted in a significant increase in extent and complexity of skull base defects, demanding more elaborate and novel reconstruction techniques to prevent cerebrospinal fluid (CSF) leakage and to improve healing. Currently, commercially available fibrin sealants are often used to reinforce the skull base reconstruction. However, problems have been reported regarding hypersensitivity reactions, efficacy, and costs. This trial aims to investigate autologous leukocyte- and platelet-rich fibrin (L-PRF) membranes as an alternative for commercially available fibrin glues in EETA-related skull base reconstruction reinforcement.
METHODS: This multicenter, prospective randomized controlled trial aims to demonstrate non-inferiority of L-PRF membranes compared to commercially available fibrin sealants in EETA cases (1) without intra-operative CSF-leak as dural or sellar floor closure reinforcement and (2) in EETA cases with intra-operative CSF-leak (or very large defects) in which a classic multilayer reconstruction has been made, as an additional sealing. The trial includes patients undergoing EETA in three different centers in Belgium. Patients are randomized in a 1:1 fashion comparing L-PRF with commercially available fibrin sealants. The primary endpoint is postoperative CSF leakage. Secondary endpoints are identification of risk factors for reconstruction failure, assessment of rhinological symptoms, and interference with postoperative imaging. Additionally, a cost-effectiveness analysis is performed.
CONCLUSIONS: With this trial, we will evaluate the safety and efficacy of L-PRF compared to commercially available fibrin sealants.
BACKGROUND: ClinicalTrials.gov NCT03910374. Registered on 10 April 2019.

Tissue engineering focuses on wound healing and tissue regeneration. Platelet-rich fibrin (PRF) is a fibrin matrix containing cytokines, growth factors and cells that are gradually released into the wound over time. This study aimed to evaluate the effect of PRF membranes on wound repair and microbial control in infected wounds. Skin wounds were performed on the dorsum of rats using a 6 mm diameter metal punch. The defects were randomly assigned into four groups (n = 12/each) accordingly to the treatment: G1, noninfected wound filled only with clot; G2, noninfected wound with PRF; G3, infected wound (S. aureus) without PRF; G4, infected wound (S. aureus) with PRF. After 7 and 14 days, macroscopic and histological analyses of the wounds were performed. Furthermore, the quantification of β-defensin in PRF was measured by ELISA. At 14 days, the groups with PRF (G2 and G4) had wound sizes significantly smaller than the original defects (6 mm) (p < 0.05) and significantly smaller than those not treated with PRF, in both the infected and noninfected groups (p < 0.05). Furthermore, the groups with infected wounds (G3 and G4) demonstrated a significantly lower inflammation score in the PRF group than in the noninfected groups (p < 0.05). In vitro analysis of β-defensin was performed in all PRF membrane groups, and the median value was 1.444 pg/mL. PRF in the wounds of both control and infected rats played an important role in the modulation of tissue healing, most notably in infected sites.

UNASSIGNED: Bone regeneration is a desired treatment outcome in implant dentistry. The primary goal of the current investigation was to assess the joint effect of low-level laser therapy (LLLT) and leukocyte- and platelet-rich fibrin (PRF) on new bone formation.
UNASSIGNED: During this experiment study, forty bone defects (8 mm in diameter) were generated in the calvaria of ten New-Zealand white rabbits. defects were filled with autogenous bone defined as the control group, autogenous bone with leukocyte- and PRF (PRF group), autogenous bone and low-level diode laser radiation (LLLT group), and autogenous bone with leukocyte- and PRF and low-level laser radiation (LP group). Laser irradiation was done every second day for 2 weeks after surgery. Five rabbits were randomly selected to be sacrificed on postoperative weeks 4 and 8. On one and two-month post-surgery, histological and histomorphometric parameters including bone formation, fibroblast, and osteoblast were assessed.
UNASSIGNED: The histological panel depicted that the ratio of fresh bone formation increased at one-and two-month postsurgery in all treatment groups compared to the control group. The most favorable results were seen in the LP group, followed by the PRF group. Based on the ANOVA test, bone neoformation was statistically significant in the LP group in comparison with the control group (P<0.001). One-month post-surgery, a higher degree of fibroblast was seen in the control group, while the last place was for LP group (118.6 ± 6.9 vs. 24.0 ± 3.2). In the PRF group, the percentage of bone formation was higher than that in the control group (13.2 ± 2.8 vs. 2.0 ± 1.2), but no significant difference when compared to the LP group (13.2 ± 2.8 vs. 19.0 ±.3.8).
UNASSIGNED: The combined L-PRF and LLLT was more likely to have a positive effect on accelerating bone regeneration and reducing fibrosis.

Leukocyte-platelet-rich fibrin (L-PRF) has been suggested for gap management for immediate implant placement when the distance is greater than 2 mm. However, there remains a paucity in hierarchically designed research to support this application. The present study aimed to evaluate the effect of L-PRF on the osseointegration parameters of dental implants placed after conventional osteotomy of surgically created bone defects that simulate post extraction sockets in a canine model after 3, 6, and 12 weeks in vivo. Eighty dental implants (Intra-Lock, Boca Raton, FL) were placed in the radius of 13 beagle dogs. The experiment consisted of 4 groups (n = 20 implants/group): 1) Regular osteotomy (Reg n/L-PRF); 2) Regular osteotomy and implant placement with L-PRF membrane (Reg L-PRF); 3) Wide osteotomy with no gap management performed, where an osteotomy/bony defect (6 mm of diameter and ~5 mm deep) was created to simulate immediate implant placement in post-extraction sockets, and the gap was left for spontaneous healing (Wide nL-PRF); and 4) Wide osteotomy with L-PRF gap management (Wide L-PRF). L-PRF membranes were obtained by blood drawn from each subject and centrifuged at 2700 rpm (408 RCF-clot) for 12 min. In the experimental groups where L-PRF was utilized, the membrane was inserted into the osteotomy site prior to implant placement. Six dogs had implants placed in the radius for 3 weeks; and 7 dogs had implants placed in the left radius for 6 weeks and in the right radius for 12 weeks. At the corresponding experimental time points, samples were harvested, and subjected to histological processing for qualitative and quantitative analyses, via bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO). Qualitative analysis demonstrated increased amounts of bone formation around the implant and within the healing chambers over time for all groups. While comparable histological features were observed for both Reg groups (L-PRF and nL-PRF), the gap management performed in Wide L-PRF group resulted in effective gap filling with improved bone growth in close proximity to the implant surface. Quantitative analyses of BIC and BAFO yielded higher values for both variables at 3 weeks for Wide L-PRF (~38% and ~56% respectively) compared to Wide nL-PRF (~20% for BIC and BAFO) (p < .03). No statistical differences were detected between Wide groups at 6 and 12 weeks, neither between Reg groups, independent of the association with or without the L-PRF membrane at all healing times. L-PRF placed within wide osteotomies, prior to implant placement, resulted in increased early bone formation compared to unfilled wide osteotomies at the early healing time (3 weeks in vivo).