Comprehensive clinical and histological evaluation of bovine hydroxyapatite bone graft with polypropylene membrane versus leukocyte- and platelet-rich fibrin for alveolar preservation after tooth extraction.

BACKGROUND: Osseointegrated implant placement in the ideal prosthetic position necessitates a sufficient residual alveolar ridge. Tooth extraction and the subsequent healing process often lead to bony deformities, characterized by a reduction in alveolar ridge height and width, resulting in unfavorable ridge architecture for dental implant placement. Several materials, including allografts, alloplastics, xenografts, and autogenous bone, are commonly used to address these concerns. In this context, leucocyte- and platelet-rich fibrin (L-PRF) emerges as a promising solution. METHODS: This case report aims to compare the clinical and histological efficacy of bovine hydroxyapatite bone graft covered with polypropylene membrane (BHAG-PM) and leucocyte- and platelet-rich fibrin (L-PRF) in preserving dental alveoli following tooth extraction. Extraction, graft placement in the alveoli, and the anterior border between extracted elements were performed for both treatment groups. RESULTS: Up to 24 months of follow-up revealed satisfactory and comparable clinical and histological outcomes. These results suggest that both BHAG-PM and L-PRF effectively promote alveolar preservation, paving the way for ideal implant placement. CONCLUSIONS: In general, bone-substitute materials are effective in reducing alveolar changes after tooth extraction. Xenograft materials should be considered as among the best of the available grafting materials for alveolar preservation after tooth extraction. Both techniques effectively preserve the alveolar bone and facilitate the placement of osseointegrated implants in ideal positions, paving the way for successful oral rehabilitation.

Platelet-rich fibrin (PRF) modified nano-hydroxyapatite/chitosan/gelatin/alginate scaffolds increase adhesion and viability of human dental pulp stem cells (DPSC) and osteoblasts derived from DPSC.

Bone tissue regeneration strategies have incorporated the use of natural polymers, such as hydroxyapatite (nHA), chitosan (CH), gelatin (GEL), or alginate (ALG). Additionally, platelet concentrates, such as platelet-rich fibrin (PRF) have been suggested to improve scaffold biocompatibility. This study aimed to develop scaffolds composed of nHA, GEL, and CH, with or without ALG and lyophilized PRF, to evaluate the scaffold's properties, growth factor release, and dental pulp stem cells (DPSC), and osteoblast (OB) derived from DPSC viability. Four scaffold variations were synthesized and lyophilized. Then, degradation, swelling profiles, and morphological analysis were performed. Furthermore, PDGF-BB and FGF-B growth factors release were quantified by ELISA, and cytotoxicity and cell viability were evaluated. The swelling and degradation profiles were similar in all scaffolds, with pore sizes ranging between 100 and 250 µm. FGF-B and PDGF-BB release was evidenced after 24 h of scaffold immersion in cell culture medium. DPSC and OB-DPSC viability was notably increased in PRF-supplemented scaffolds. The nHA-CH-GEL-PRF scaffold demonstrated optimal physical-biological characteristics for stimulating DPSC and OB-DPSC cell viability. These results suggest lyophilized PRF improves scaffold biocompatibility for bone tissue regeneration purposes.

The Biological Role of Platelet Derivatives in Regenerative Aesthetics.

Bioproducts derived from platelets have been extensively used across various medical fields, with a recent notable surge in their application in dermatology and aesthetic procedures. These products, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), play crucial roles in inducing blood vessel proliferation through growth factors derived from peripheral blood. PRP and PRF, in particular, facilitate fibrin polymerization, creating a robust structure that serves as a reservoir for numerous growth factors. These factors contribute to tissue regeneration by promoting cell proliferation, differentiation, and migration and collagen/elastin production. Aesthetic medicine harnesses these effects for diverse purposes, including hair restoration, scar treatment, striae management, and wound healing. Furthermore, these biological products can act as adjuvants with other treatment modalities, such as laser therapy, radiofrequency, and microneedling. This review synthesizes the existing evidence, offering insights into the applications and benefits of biological products in aesthetic medicine.

Osteogenic potential of apical papilla stem cells mediated by platelet-rich fibrin and low-level laser.

To evaluate the osteogenic potential of platelet-rich fibrin (PRF) and low-level laser therapy (LLLT) on human stem cells from the apical papilla (SCAP) we isolated, characterized, and then cultured in an osteogenic medium cells with PRF and/or LLLT (660 nm, 6 J/m2-irradiation). Osteogenic differentiation was assessed by bone nodule formation and expression of bone morphogenetic proteins (BMP-2 and BMP-4), whereas the molecular mechanisms were achieved by qRT-PCR and RNA-seq analysis. Statistical analysis was performed by ANOVA and Tukey's post hoc tests (p < 0.05* and p < 0.01**). Although PRF and LLLT increased bone nodule formation after 7 days and peaked at 21 days, the combination of PRF + LLLT led to the uppermost nodule formation. This was supported by increased levels of BMP-2 and -4 osteogenic proteins (p < 0.005). Furthermore, the PRF + LLLT relative expression of specific genes involved in osteogenesis, such as osteocalcin, was 2.4- (p = 0.03) and 28.3- (p = 0.001) fold higher compared to the PRF and LLLT groups, and osteopontin was 22.9- and 1.23-fold higher, respectively (p < 0.05), after 7 days of interaction. The transcriptomic profile revealed that the combination of PRF + LLLT induces MSX1, TGFB1, and SMAD1 expression, after 21 days of osteogenic differentiation conditions exposition. More studies are required to understand the complete cellular and molecular mechanisms of PRF plus LLLT on stem cells. Overall, we demonstrated for the first time that the combination of PRF and LLLT would be an excellent therapeutic tool that can be employed for dental, oral, and craniofacial repair and other tissue engineering applications.

Sema4D is diminished in leukocyte platelet-rich fibrin and impairs pre-osteoblastic MC3T3-E1 cells' functionality.

OBJECTIVE: Semaphorin 4D (Sema4D) is a coupling factor expressed on osteoclasts that may hinder osteoblast differentiation. Since the leukocyte platelet-rich fibrin (L-PRF) membrane promotes growth factor concentration, this study aims to quantify the amount of Sema4D in L-PRF membranes, and analyze the impact of Sema4D on osteoblast cell function in vitro. DESIGN: Enzyme-linked immunosorbent assay (ELISA) was used to quantify the levels of Sema4D in both L-PRF and whole blood (serum). To analyze the impairment of Sema4D on osteoblasts, MC3T3-E1 cells were induced to osteogenic differentiation and exposed to Sema4D ranging from 10 to 500 ng/ml concentrations. The following parameters were assayed: 1) cell viability by MTT assay after 24, 48, and 72 h; 2) matrix mineralization by Alizarin Red staining after 14 days, 3) Runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN), osteonectin (ONC), bone sialoprotein (BSP) and alkaline phosphatase (ALP) gene expression by qPCR. For all data, the significance level was set at 5%. RESULTS: The amount of Sema4D in the whole blood (serum) was higher than in L-PRF. Osteoblasts exposed to Sema4D at all tested concentrations exhibited a decrease in matrix mineralization formation as well in RUNX-2, OCN, ONC, BSP, and ALP gene expression (p < 0.05). CONCLUSION: The presence of Sema4D, a molecule known for suppressing osteoblast activity, diminishes within L-PRF, enhancing its ability to facilitate bone regeneration.

Histological, Immunohistochemical, Biomechanical, and Wettability Evaluations of the Leukocyte- and Platelet-Rich Fibrin Membranes Derived from Canine Blood.

This study aimed to perform histological, immunohistochemical, biomechanical, and wettability assessments of leukocyte- and platelet-rich fibrin (L-PRF) membranes obtained from the blood of healthy dogs. Ten client-owned Labrador Retriever dogs were enrolled. Blood samples were obtained from the external jugular vein using a vacuum tube without anticoagulant, which was immediately centrifuged at 400g for 12 min in a dedicated centrifuge. The L-PRF clot was removed from the tube, and the red clot was released from the buffy coat using a spatula. The membrane was produced using a PRF box. Histological examination identified the three portions of the L-PRF membranes. The first portion was composed mainly of red blood cells with the presence of a low number of leukocytes among them. The second portion was composed of white blood cells, mainly neutrophils. The third portion was composed of the fibrin network which was characterized by acidophilic staining. The immunohistochemical analysis showed that vascular endothelial growth factor and platelet-derived growth factor were expressed in all samples at different intensities, both in cellular components and fibrin mesh. The tensile test and wettability assessments were measured in membranes 30 min and 3 h after production. The 30 min L-PRF membranes supported twice the ultimate tensile strength compared to 3 h L-PRF membranes. The wettability of the 30 min sample membranes was statistically higher than the 3 h sample membranes. In conclusion, the centrifugation protocol allowed production of the L-PRF membrane using canine blood and this was confirmed by histological and immunohistochemical analysis. The mechanical resistance and wettability of the L-PRF membrane were significantly reduced over time.

Effect of platelet-rich fibrin (PRF) membranes on the healing of infected skin wounds.

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 ß-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 ß-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.

Tratamiento de heridas complejas mediante fibrina rica en plaquetas y leucocitos (L-PRF), experiencia inicial de un centro / Treatment of complex wounds using platelet rich fibrin and leukocytes (L-PRF), initial experience of a center

Resumen Introducción El uso de concentrados plaquetarios para el tratamiento de heridas complejas y regeneración tisular está siendo ampliamente utilizado a nivel mundial. Durante el último tiempo, la segunda generación de concentrados plaquetarios, particularmente el L-PRF, ha permitido tratar de manera efectiva a pacientes con esta patología. Debido a su bajo costo y versatilidad, ha sido posible aplicar esta técnica en variadas situaciones clínicas con buenos resultados. El objetivo de este trabajo es presentar nuestra experiencia utilizando L-PRF para la curación de heridas complejas (CHC) como una alternativa al uso de injertos de distinto grado de complejidad. Materiales y Método: Se realizó un análisis prospectivo de una serie de casos de pacientes que fueron sometidos a tratamiento quirúrgico de heridas complejas mediante el uso de L-PRF en el Hospital Santiago Oriente - Luis Tisné Brousse, entre los meses de enero de 2017 y diciembre de 2018. Mediante examen clínico y parámetros de inclusión, de éxito y de fracaso definidos previamente, se evaluó un total de 11 pacientes con heridas complejas a los cuales se les realizó un tratamiento local con injerto de L-PRF. Resultados: _La etiología de las heridas fue variada. 8 (72%) de los casos lograron una epitelización del 100% y 3 (28%) fracasaron. Se identificaron factores predisponentes para el fracaso de la técnica, y también fue posible establecer una relación de predicción de éxito en donde se relaciona una probabilidad alta de epitelización cuando la granulación de la herida ocurre durante los primeros 10 días sobre el injerto de L-PRF. Conclusión: El tratamiento de heridas complejas mediante L-PRF es una alternativa factible, de bajo costo y requerimientos (comparada con el uso de injertos, colgajos y sustitutos dérmicos), es segura en la resolución de heridas complejas, permitiendo disminuir la morbilidad, los costos asociados al tratamiento y estadía hospitalaria.

Introduction: The use of platelet concentrates for the treatment of complex wounds and tissue regenera-tion is being widely used worldwide. During the last time, the second generation of platelet concentrates, particularly L-PRF, has made it possible to effectively treat patients with this pathology. Due to its low cost and versatility, it has been possible to apply this technique in various clinical situations with good results. The objective of this work is to present our experience using L-PRF for the healing of complex wounds (HCC) as an alternative to the use of grafts of different degrees of complexity. Materials and Method: A prospective analysis was carried out with a series of cases who underwent surgical treatment of complex wounds using L-PRF at Santiago Oriente - Luis Tisné Brousse Hospital, between the months of January 2017 and December 2018. Through clinical examination and previously defined inclusion, success, and failure parameters, a total of 11 patients with complex wounds were evaluated who underwent local treatment with an L-PRF graft. Results: The etiology of the wounds was varied. 8 (72%) of the cases achieved 100% epithelialization and 3 (28%) failed. Predisposing factors for the failure of the technique were identified, and it was also possible to establish a predictive relationship of success where a high probability of epithelialization is related when the granulation of the wound occurs during the first 10 days on the L-PRF graft. Conclusion: The treatment of complex wounds using L-PRF is a feasible alternative, with low cost and requirements (compared to the use of grafts, flaps and dermal substitutes) and safe in the resolution of complex wounds, allowing to reduce morbidity, the costs associated with treatment and hospital stay.

Efecto de la Fibrina Rica en Plaquetas en la Curación de los Tejidos Blandos de Alveolos Post Exodoncia Atraumática. Un Ensayo Clínico Controlado Aleatorizado Cruzado a Ciego Simple / Effect of the platelet-rich fibrin on the healing of the soft tissues of sockets after atraumatic exodontics. A single-blind cross-randomized controlled clinical trial

El objetivo de este estudio fue determinar el efecto de la fibrina rica en plaquetas (FRP) en la curación de los tejidos blandos de alveolos post exodoncia atraumática. El presente es un ensayo clínico controlado aleatorizado a ciego simple y de diseño cruzado. Se llevó a cabo en el Servicio de Odontología del Hospital Distrital Santa Isabel del Porvenir - Perú, durante los años 2016 y 2017. La muestra estuvo conformada por 51 pacientes cuyos alveolos post exodoncia fueron divididos de forma aleatoria en 2 grupos, cada paciente firmó un consentimiento informado. Al grupo A (control) se le dejó con un coágulo de sangre para su curación normal y al grupo B (experimental) se le administró FRP (como tapón y membrana), obtenido según el protocolo de Choukroun. Para determinar el efecto del FRP en la curación de los tejidos blandos de los alveolos post exodoncia atraumática se utilizó el índice de Landry. Las medidas se realizaron a los 7 y 14días después de la cirugía.Para la comparación de cada una de las variables del estudio se utilizó el Test de Mc Nemar y el Test exacto de Fisher. La significación estadística fue del 5 %. Al comparar ambos grupos en la curación de los tejidos blandos de alveolos post exodoncia atraumática se encontró que existe una diferencia estadísticamente significativa a los 7 y 14 días después de la cirugía (p0.05). La FRP presenta un efecto positivo en la curación de los tejidos blandos de alveolos post exodoncia atraumática de forma independiente del sexo y la edad.

The objective of the study was to determine the effect of platelet-rich fibrin (PRF) on the healing of soft tissues of socket after atraumatic exodontia. The present is a single-blind, cross-sectional randomized controlled trial. It was carried out in the Dental Service of the Santa Isabel District Hospital of Porvenir - Peru, during the years 2016 and 2017. The sample consisted of 51 patients whose alveoli post exodontia were randomly divided into 2 groups, each patient signed an informed consent. Group A (control) was left with a blood clot for normal healing and group B (experi- mental) was given PRF (as a plug and membrane), obtained according to the Choukroun protocol. The effect of PRF on the healing of the soft tissues of the alveoli after atraumatic exodontia was used the Landry index. The measurements were made at 7 and 14 days after surgery. For the comparison of each one of the variables of the study, the Mc Nemar test and the Fisher exact test were used. The statistical significance was 5 %. When comparing both groups in the healing of the soft tissues of alveoli after atraumatic exodontia, a statistically significant difference was found at 7 and 14 days after surgery (p 0.05). The PRF has a positive effect on the healing of the soft tissues of the alveoli after atraumatic exodontia independently of sex and age.

In vivo evaluation of the biocompatibility and biodegradation of a new denatured plasma membrane combined with liquid PRF (Alb-PRF).

Guided bone regeneration (GBR) is a process that involves the regeneration of bone defects through the application of occlusive membranes that mechanically exclude the population of non-osteogenic cells from the surrounding soft tissue. Interestingly, platelet-rich fibrin (PRF) has previously been proposed as an autologous GBR membrane despite its short-term resorption period of 2-3 weeks. Recent clinical observations have demonstrated that, by heating a liquid platelet-poor plasma (PPP) layer and mixing the cell-rich buffy coat zone, the resorption properties of heated albumin gel with liquid-PRF (Alb-PRF) can be significantly improved. The aim of this study was to evaluate the inflammatory reaction, biocompatibility, and extended degradation properties of a new autologous Alb-PRF membrane in comparison to commonly utilized standard PRF after nude mice implantation, according to ISO 10993-6/2016. Two standard preparations of PRF (L-PRF and H-PRF) were compared to novel Alb-PRF following subcutaneous implantation at 7, 14, and 21 days. All groups demonstrated excellent biocompatibility owing to their autologous sources. However, it is worth noting that, while both L-PRF and H-PRF membranes demonstrated significant or complete resorption by 21 days, the Alb-PRF membrane remained volume-stable throughout the duration of the study. This study demonstrates-for the first time, to the best of our knowledge-a marked improvement in the membrane stability of Alb-PRF. This indicates its future potential for use as a biological barrier membrane for GBR procedures with a long-lasting half-life, or as a biological filler material in esthetic medicine applications. Thus, further studies are warranted to explore future clinical applications in various fields of medicine.

Methodological variations affect the release of VEGF in vitro and fibrinolysis' time from platelet concentrates.

Blood Concentrates (BCs) are autologous non-transfusional therapeutical preparations with biological properties applied in tissue regeneration. These BCs differ in the preparation method, in fibrin network architecture, growth factors release as well as in platelet/cell content. Methodological changes result in distinct matrices that can compromise their clinical effectiveness. The present study evaluated the influence of different g-forces and types of tubes in the release of vascular endothelial growth factor (VEGF) from platelet-rich fibrin (PRF) as a function of time. The PRF-like samples were obtained with three g-forces (200, 400, and 800 x g) for 10 minutes in pure glass tubes or in polystyrene-clot activator tubes. Scanning and Transmission electron microscopy was used to morphometric analyzes of PRF's specimens and flow cytometry was used to quantify VEGF slow release until 7 days. Our results showed that platelets were intact and adhered to the fibrin network, emitting pseudopods and in degranulation. The fibrin network was rough and twisted with exosomic granulations impregnated on its surface. An increase in the concentration of VEGF in the PRF supernatant was observed until 7 days for all g forces (200, 400 or 800 xg), with the highest concentrations observed with 200 x g, in both tubes, glass or plastic. Morphological analyzes showed a reduction in the diameter of the PRF fibers after 7 days. Our results showed that g-force interferes with the shape of the fibrin network in the PRF, as well as affect the release of VEGF stored into platelets. This finding may be useful in applying PRF to skin lesions, in which the rapid release of growth factors can favor the tissue repair process. Our observations point to a greater clarification on the methodological variations related to obtaining PRF matrices, as they can generate products with different characteristics and degrees of effectiveness in specific applications.

Inflammatory cell profile using different autologous fibrin protocols.

Autologous fibrin has been widely used in surgical procedures for both soft and hard tissue repair. There are different protocols and devices to obtain this matrix, with varying centrifugal time, gravity force, speed, angle of the sample tube and spinning radius. The aim of this study was to compare three methods of obtaining autologous fibrin: L-PRF using the Intra-Spin L-PRF centrifuge (Dohan protocol), the advanced PRF (A-PRF) using the Intra-Spin L-PRF centrifuge and autologous leukocyte fibrin (ALF), using the Kasvi centrifuge. Venous blood was collected from 7 healthy volunteers, which were submitted to the 3 different methods of centrifugation. The membranes were tissue-processed and evaluated by immunohistochemistry for CD3, CD20, CD68 and CD138. For CD68+, a lower number of cells was immunolabelled in the L-PRF group when compared to the other groups (A-PRF and ALF). For CD3+, a lower number of immunolabellated cells was observed in the ALF group when compared to the remaining groups (p < 0.05). In the A-PRF group, the CD20+ cell count was lower than in the remaining groups. No difference was observed in CD138+ cell counts between the groups. The 3 protocols tested are suitable for obtaining autologous fibrin membranes.

Assessment of platelet-rich fibrin in the maintenance and recovery of cell viability of the periodontal ligament.

This study analyzed the efficacy of autologous platelet-rich fibrin (PRF) in maintaining and recovering cell viability of the periodontal ligament (PDL). The PDL cells were isolated from 45 extracted teeth randomly distributed among 6 groups: 5 min, 1 h, 2 h, PRF 30 min, PRF 1 h and PRF 2 h. In the groups 5 min, 1 h and 2 h (n = 5), the teeth were kept dry in extra-alveolar times of 5 min, 1 h and 2 h respectively. The teeth of the groups PRF 30 min, PRF 1 h and PRF 2 h (n = 10) were kept dry at extra-alveolar times of 30 min, 1 and 2 h followed by immersion in PRF for 45 min. PDL cells were isolated by enzymatic digestion with type II collagenase and dispase, counted and analyzed for viability with Trypan blue vital dye in Neubauer chamber. The variables total number of cells and cell viability demonstrated that in the 5 min, 1 h and 2 h groups there was a decrease after the extra-alveolar dry times of 1 and 2 h. In comparison with the total number of cells, group 1 h, considered immediate reimplantation, did not present statistical difference when compared to the groups PRF 30 min, PRF 1 h and 2 h, a result that demonstrates that PRF assists in cell maintenance and recovery. PRF provided increased cell viability in relation to the different dry extra-alveolar times analyzed (p < 0.001). Autologous PRF presented effectiveness in maintaining and recovering PDL cells from extracted teeth and kept dry for up to 2 h.

Platelet-rich fibrin and collagen membrane in the preservation of the alveolar bone: Feasibility of the elemental inorganic composition and scanning electron microscopy analysis.

The success of dental implants is related to the amount, quality, and composition of the alveolar bone. The placement of platelet-rich fibrin (PRF) clot associated with a resorbable collagen membrane (RCM) in a postextraction alveolus is a technique used for ridge preservation. This case report study analyzed the ultrastructural characteristics of cross-sectioned alveolar bone that received PRF and RCM using scanning electron microscopy and the inorganic composition using "energy dispersive X-ray spectrometry," in order to explore the feasibility of this method to clinical studies. Three alveolar bone samples from two male patients (37 and 58 years old), obtained in the procedure of placing the dental implant, were analyzed. Two bone samples previously received PRF and RCM (M37 and M58), the third sample represented a physiological bone formation without treatment (M37-control). The bone sample M37 showed irregularly shaped islets of calcified material intermingled with connective tissue. The other samples, from the 58-year-old patient with PRF and RCM (M58); and the other untreated bone sample from the same 37-year-old patient (M37-control) showed similar ultrastructural morphology with trabecular conformation without islets agglomerations. The inorganic composition analysis showed higher concentrations of calcium and phosphorus in both samples treated with PRF and RCM in comparison to the untreated bone sample. The Ca/P ratio was higher in the M37 sample compared to the others samples. The results showed morphology and inorganic composition differences among the treatments used, suggesting that this method is feasible to analyze parameters of the alveolar bone tissue.

Production and evaluation of leukocyte- and thrombocyte-rich fibrin membranes in birds.

The aim of this study was the preparation and histological evaluation of Leukocyte- and Thrombocyte-Rich Fibrin (L-TRF) membranes obtained from the blood of four bird species. Forty adult healthy birds were divided into four groups of equal size: G1 - macaws, G2 - domestic chickens, G3 - parrots, G4 - toco toucans. A total of 0.5 mL of blood was collected from each bird, put into a glass tube without anticoagulant and centrifuged at 3000 rpm for 10 min. L-TRF membranes produced after compression of the clot were processed for histological analysis. The ratio of thrombocytes/area was not significantly different among Groups G2, G3 and G4, but a significant difference was found between Groups G1 and G2 with the highest thrombocyte concentration/area in G1. The groups did not differ statistically in the number of leukocytes/area. The fibrin-to-cells ratio did not vary statistically among Groups G1, G2 and G3, but this ratio was significantly higher in Group G4 than in the other groups. The thrombocyte-to-leukocyte ratio was the highest in Group G1, but it did not differ among Groups G2, G3 and G4. In conclusion, the centrifugation protocol allowed the production of L-TRF membranes in the four bird species studied. Histologically, cell ratios were analogous in domestic chickens and parrots, and macaws had the highest ratio of thrombocytes.

Leucocyte- and platelet-rich fibrin (L-PRF) as a regenerative medicine strategy for the treatment of refractory leg ulcers: a prospective cohort study.

Chronic wounds (VLU: venous leg ulcer, DFU: diabetic foot ulcer, PU: pressure ulcer, or complex wounds) affect a significant proportion of the population. Despite appropriate standard wound care, such ulcers unfortunately may remain open for months or even years. The use of leukocyte- and platelet-rich fibrin (L-PRF) to cure skin ulcers is a simple and inexpensive method, widely used in some countries but unknown or neglected in most others. This auto-controlled prospective cohort study explored and quantified accurately for the first time the adjunctive benefits of topical applications of L-PRF in the management of such refractory ulcers in a diverse group of patients. Forty-four consecutive patients with VLUs (n = 28, 32 wounds: 17 ≤ 10 cm2 and 15 > 10 cm2), DPUs (n = 9, 10 wounds), PUs (n = 5), or complex wounds (n = 2), all refractory to standard treatment for ≥3 months, received a weekly application of L-PRF membranes. L-PRF was prepared following the original L-PRF method developed more than 15 years ago (400g, 12 minutes) using the Intra-Spin L-PRF centrifuge/system and the XPression box kit (Intra-Lock, Boca Raton, FL, USA; the only CE/FDA cleared system for the preparation of L-PRF). Changes in wound area were recorded longitudinally via digital planimetry. Adverse events and pain levels were also registered. All wounds showed significant improvements after the L-PRF therapy. All VLUs ≤ 10 cm2, all DFUs, as well as the two complex wounds showed full closure within a 3-month period. All wounds of patients with VLUs > 10 cm2 who continued therapy (10 wounds) could be closed, whereas in the five patients who discontinued therapy improvement of wound size was observed. Two out of the five PUs were closed, with improvement in the remaining three patients who again interrupted therapy (surface evolution from 7.35 ± 4.31 cm2 to 5.78 ± 3.81 cm2). No adverse events were observed. A topical application of L-PRF on chronic ulcers, recalcitrant to standard wound care, promotes healing and wound closure in all patients following the treatment. This new therapy is simple, safe and inexpensive, and should be considered a relevant therapeutic option for all refractory skin ulcers.