Fibrin Preparations Research Articles

Endobronchial Closure for Peripheral Pulmonary Air Leakage

Introduction: A minimally invasive alternative to surgery for treating pneumothorax has been developed, aiming to reduce risks while maintaining efficacy. This study conducted basic experiments using ex vivo and in vivo pig lung employing a super-thin catheter for treatment. This new device injects fibrin glue directly into the responsible lesion to close the air leak, which has two features: thin design and double-lumen. Methods: The experimental setup involved utilizing trachea and both lung specimens from pigs under positive pressure ventilation. To simulate pneumothorax, artificial fistulas were created on the lung surfaces. The super-thin catheter, guided through a bronchoscope near the fistula, was used to embolize the peripheral bronchus by injecting a fibrin preparation. Then, an air leak test was conducted afterward to assess the efficacy of the treatment. Additionally, a similar pneumothorax model was induced in alive pig under general anesthesia to evaluate its curability. Results: In the extracted pig lungs, embolization was performed in 21 cases, resulting in the cessation of air leaks in 19 cases, corresponding to a 90.5% cure rate. Notably, no major adverse events occurred with the treatment devices. Similarly, in living pigs, pneumothorax was successfully treated, with no recurrence observed up to the seventh postoperative day. Conclusion: The novel treatment device utilizing a super-thin catheter offers a minimally invasive and highly curative option for pneumothorax. These promising results suggest the potential for further development and human clinical trials, which could revolutionize the treatment of pneumothorax, reducing risks and improving outcomes.

Metformin-suppressed platelet's function in vitro: Possible relation to delayed or failure of platelet-rich fibrin preparation

Platelet-rich fibrin (PRF) is a popular autologous blood-derived biomaterial that is used in regenerative therapy. Owing to its simple preparation without additional factors, the PRF quality directly reflects the characteristics of individual blood samples. Antiplatelet or anticoagulant drugs can hamper the successful preparation of PRF. We recently observed similar phenomena in metformin-taking type-2 diabetics (T2DM). Thus, we hypothesized that metformin interferes with platelet function, thereby suppressing coagulation. For practical reasons, leukocyte- and platelet-rich plasma was prepared from healthy male donors (n = 9–15, age: 26–80 years) and treated with metformin (1–10 mM) for 24–72 h. Intrinsic and extrinsic coagulation activities were evaluated using prothrombin time (PT) and activated partial thromboplastin time (ATPP). Platelet adhesion and aggregation assays were performed using ADP stimulation. Among the parameters tested, APTT was the most sensitive and was significantly prolonged in the concentration range of 1–10 mM in a time- and concentration-dependent manner. Although obtained from healthy platelets and relatively higher concentrations of metformin, these findings suggest that metformin may induce further dysfunction of platelets to suppress intrinsic coagulation activity in T2DM patients, leading to failure of PRF preparation. This phenomenon may not have a severe impact on clinical diabetology or hematology. However, clinicians using PRF are recommended to be more sensitive to such information to avoid unexpected events in clinical settings.

Progress in Application of Concentrated Growth Factor in Oral Tissue Regeneration

Tissue regeneration is an important engineering method for the treatment of oral soft and hard tissue defects.Growth factors,as one of the three elements of tissue regeneration,are a necessary condition for tissue regeneration.Concentrated growth factor(CGF)is a new generation of blood extract prepared by changing the centrifugal speed on the basis of the preparation of platelet-rich plasma(PRP)and platelet-rich fibrin(PRF).It contains abundant growth factors and a fibrin matrix with a three-dimensional network structure,being capable of activating angiogenesis and promoting tissue regeneration and healing.CGF has been widely used in the repair and regeneration of oral soft and hard tissues.This paper introduces the preparation and composition of CGF and reviews the application of CGF in oral implantation and the regeneration of oral bone tissue,periodontal tissue,and dental pulp tissue.

Medical care for postpartum bleeding: A literature review

Relevance: According to modern literature, over the past decade, there has been no tendency in the world to reduce maternal mortality from postpartum hemorrhage (PPH). In Kazakhstan, evidence-based medicine clinical recommendations on prevention and algorithm of action for obstetric bleeding have been developed and recommended for use since 2010. We conducted a literary search for existing innovative methods of PPH prevention and treatment based on the study of clinical recommendations of many developed countries, WHO, FIGO, and scientific publications. There exist separate algorithms for managing PPH during vaginal delivery or cesarean section.The study aimed to explore the existing innovative methods of preventing and treating postpartum hemorrhage to determine the most effective medical care for postpartum hemorrhage.Materials and methods: The literature search included papers published on PubMed in English from January 1, 2018, to November 31, 2022. The search was done by keywords including “pregnancy,” “PPH,” “pregnancy complication,” “pregnancy outcomes,” and “tranexamic acid,” “guideline.” Results: Today, there are separate algorithms for managing PPH during vaginal delivery or cesarean section. Fibrin preparations and fibrinogen concentrate are recommended for use. When PPH occurs, it is important to communicate with family members to further inform them about the patient’s condition. The routine use of the Allgower shock index for accurate calculation of the volume of blood loss is proposed. It is proposed to use antifibrinolytic drugs not only for therapeutic purposes but also for prophylactic purposes. It is important to carry out adequate infusion-transfusion therapy to prevent iatrogenic coagulopathy. Conclusion: Introducing the above modern technologies into practical healthcare does not require high economic costs and can be used in obstetric institutions at all levels of medical care for PPH.

Platelet Rich Fibrin (PRF) - A Novel Regenerative Material in oral and maxillofacial surgery - A LITERATURE REVIEW

The development of novel regenerative material to reduce inflammation and enhance healing process is one of the greatest task in clinical research. PRF ( platelet rich fibrin) is an second generation platelet concentrate which has gained popularity in recent years due to its unique regenerative process. Platelet Rich Fibrin is completely autologous material with extended growth factor release compared to other growth concentrates. The standard quality and quantity of the fibrin matrix , leukocytes, platelets, and growth factors of PRF demands a standard protocol for preparation. The use of Platelet Rich Fibrin treatment has shown increased cellular proliferation, osteogenesis and mineralisation thereby enhancing wound healing capacity. Due to its versatility Platelet Rich Fibrin serves as workhorse in wound healing. This Review article attempts to encapsulate the technique, it’s preparation and use of Platelet Rich Fibrin in the field of oral and maxillofacial surgery.

Assessment of Bone Density around Dental Implants Using Two Platelet-Rich Fibrin Protocols (A Comparative Clinical Study)

Aims: The current study aimed to compare bone density means around dental implants covered with one of two platelet rich fibrin preparation protocols (Standard-Platelet Rich Fibrin and Advanced-Platelet Rich Fibrin) using standard intraoral digital periapical radiographs. Materials and methods: A total of ten male patients with an age range of 28-51 years participated in this split-mouth clinical study. The patients were divided into two groups based on the platelet rich fibrin (PRF) protocol to be used with dental implant insertion into positive control (S-PRF) and study group (A-PRF). Each patient represented the two groups in which he received 2 dental implants; ten implants for each group (a total of 20 dental implants) of standard length and diameter in the posterior mandibular extraction sites of ipsilateral or contralateral side. In the positive control group, the standard PRF protocol was to be used to prepare the PRF clot. In the study group, the advanced PRF protocol was to be used to prepare the PRF clot. Both PRF membranes were to be instilled inside the osteotomy bed during dental fixture installation. Following the installation of dental implants and as a basis for comparison between both groups, densitometric analysis of bone around dental implants at immediate, four, eight and twelve weeks scheduled visits were made. Results: Total densitometric analysis results showed no significant difference within S-PRF group, within A-PRF group and between both groups, with the highest mean (167.07) being at twelve weeks after surgery in the A-PRF group. Conclusions: Both S-PRF and A-PRF, similarly enhanced and maintained bone density (synergistic effect) throughout the of study and as disclosed by densitometric values. The use of PRF in its current forms seems to be an accepted minimally invasive approach with good clinical results.

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.

Blood Clots versus PRF: Activating TGF-β Signaling and Inhibiting Inflammation In Vitro.

The preparation of platelet-rich fibrin (PRF) requires blood centrifugation to separate the yellow plasma from the red erythrocyte fraction. PRF membranes prepared from coagulated yellow plasma are then transferred to the defect sites to support tissue regeneration. During natural wound healing, however, it is the unfractionated blood clot (UBC) that fills the defect site. It is unclear whether centrifugation is necessary to prepare a blood-derived matrix that supports tissue regeneration. The aim of the present study was to compare lysates prepared from PRF and UBC based on bioassays and degradation of the respective membranes. We report here that lysates prepared from PRF and UBC membranes similarly activate TGF-β signaling, as indicated by the expression of interleukin 11 (IL-11), NADPH oxidase 4 (NOX-4) and proteoglycan 4 (PRG4) in gingival fibroblasts. Consistently, PRF and UBC lysates stimulated the phosphorylation and nuclear translocation of Smad3 in gingival fibroblasts. We further observed that PRF and UBC lysates have comparable anti-inflammatory activity, as shown by the reduction in lipopolysaccharide (LPS)-induced IL-6, inducible nitric oxidase synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in RAW264.7 cells. Moreover, inflammation induced by Poly (1:C) HMW and FSL-1, which are agonists of Toll-like receptor (TLR) 3 and 2/6, respectively, was reduced by both PRF and UBC. PRF and UBC lysates reduced the nuclear translocation of p65 in LPS-induced RAW264.7 cells. In contrast to the similar activity observed in the bioassays, UBC membranes lack the structural integrity of PRF membranes, as indicated by the rapid and spontaneous disintegration of UBC membranes. We show here that the lysates prepared from PRF and UBC possess robust TGF-β and anti-inflammatory activity. However, visual inspection of the PRF and UBC membranes confirmed the negative impact of erythrocytes on the structural integrity of membranes prepared from whole blood. The data from the present study suggest that although both UBC and PRF have potent TGF-β and anti-inflammatory activity, UBC does not have the strength properties required to be used clinically to prepare applicable membranes. Thus, centrifugation is necessary to generate durable and clinically applicable blood-derived membranes.

Responses of promyelocytic leukemia HL60 cells as an inflammatory cell lineage model to silica microparticles used to coat blood collection tubes

BackgroundThe preparation of platelet-rich fibrin (PRF) requires glass blood collection tubes, and thus, the shortage or unavailability of such tubes has driven clinicians to search for suitable substitutes, such as silica-coated plastic tubes. However, we have previously demonstrated the cytotoxicity of silica microparticles (MPs) used in plastic tubes to cultured human periosteal cells. To further establish the effects of silica MPs on inflammation, we examined silica MP-induced changes in a human promyelocytic cell model in vitro.MethodsHuman promyelocytic HL60 cells were used either without chemical induction or after differentiation induced using phorbol myristate acetate (PMA) or dimethyl sulfoxide. HL60 cells, osteoblastic MG63, and Balb/c mouse cells were treated with silica MPs, and their surface ultrastructure and numbers were examined using a scanning electron microscope and an automated cell counter, respectively. Differentiation markers, such as acid phosphatase, non-specific esterase, and CD11b, were visualized by cytochemical and immunofluorescent staining, and superoxide dismutase (SOD) activity was quantified.ResultsRegardless of SOD activity, silica cytotoxicity was observed in MG63 and Balb/c cells. At sub-toxic doses, silica MPs slightly or moderately upregulated the differentiation markers of the control, PMA-induced monocytic, and dimethyl sulfoxide-induced granulocytic HL60 cells. Although SOD activity was the highest (P < 0.05) in PMA-induced cells, a silica-induced reduction in cell adhesion was observed only in those cells (P < 0.05).ConclusionsSilica MP contamination of PRF preparations can potentially exacerbate inflammation at implantation sites. Consequently, unless biomedical advantages can be identified, silica-coated plastic blood collection tubes should not be routinely used for PRF preparations.

The Uses and Application of Platelet Rich Fibrin in Clinical Practice

Platelet derivatives are commonly used in wound healing and tissue regeneration. Different procedures of platelet preparation may differentially affect growth factor release and cell growth. Preparation of platelet-rich fibrin (PRF) is accompanied by release of growth factors, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor b1 (TGFb1), and several cytokines. When compared with the standard procedure for platelet-rich plasma (PRP), PRF released 2-fold less PDGF, but 415-fold and 42-fold VEGF and TGF b1, respectively.

Injectable platelet-rich fibrin for perioral rejuvenation as assessed by 3D lip volume imaging.

Various injectable autologous platelet aggregate preparations have been developed and used for facial rejuvenation. Limited evidence exists for the use of these for augmentation of the lip. This prospective, uncontrolled, single-center study evaluated the qualitative and quantitative effects of an injectable platelet-rich fibrin preparation (known as i-PRF+) for lip augmentation. PRF® PROCESS system technology was used to prepare i-PRF+ supernatant. Ten healthy females were included in the study and received a single intradermal injection of i-PRF+ in the upper and lower lips (5ml in each quadrant, total ~2ml). Participants were followed for 3months post-procedure. The efficacy of the procedure was assessed qualitatively by a subjective patient-reported outcome (FACE-Q) assessment and quantitatively by objective 3D skin surface volume analysis (ProFace® ) at baseline and after 3months. FACE-Q scales that measure satisfaction with skin and lip showed a statistically significant improvement from baseline (p=0.04 and p=0.02, respectively). Satisfaction with lip lines showed a numerical improvement with mean total scores for adverse effect scales related to the skin and lips reduced at 2weeks post-procedure (p=0.03 and p=0.13, respectively). Overall lip volume at 3-month follow-up was unchanged (p=0.11). The treatment was well tolerated with only minor adverse effects. A single session of i-PRF+ injections resulted in significant lip rejuvenation at 3-month follow-up, shown by improved patient-reported outcome measure. No significant change in lip volume was observed.

Assessment of Dental Implant Stability Using Two Platelet-Rich Fibrin Proto-cols (A Comparative Clinical Study)

Aims: The current study aimed to compare implant stability of dental implants covered with one of two - platelet rich fibrin preparation protocols namely Standard-Platelet Rich Fibrin and Advanced-Platelet Rich Fibrin) using radiofrequency assessment. Materials and methods: A total of ten male patients with an age range of 28-51 years participated in this split-mouth clinical study. The patients were divided into two groups based on the platelet rich fibrin (PRF) protocol to be used with dental implant insertion into positive control (S-PRF) and study group (A-PRF). Each patient represented the two groups in which he received 2 dental implants; ten implants for each group (a total of 20 dental implants) of standard length and diameter in the posterior mandibular extraction sites of ipsilateral or contralateral side. In the positive control group, the standard PRF protocol was to be used to prepare the PRF clot. In the study group, the advanced PRF protocol was to be used to prepare the PRF clot. Both PRF membranes were to be instilled inside the osteotomy bed during dental fixture installation. Following the installation of dental implants; radiofrequency assessment using Osstell Mentor Device immediately after insertion, four, eight; twelve weeks post-operative as secondary outcomes were conducted. Results: When comparing ISQ means of dental implants between both group protocols, the Friedman test values of ISQ means showed no statistically significant difference between them at the immediate day of surgery, four weeks, eight weeks and twelve weeks post-surgery yet showed increased levels of ISQ at end of the trial. Conclusions: Both S-PRF and A-PRF, similarly enhanced and maintained dental implant stability hence maintain osseointegration (synergistic effect) throughout the period of study and as disclosed by ISQ values. The use of PRF in its current forms seems to be an accepted minimally invasive approach with good clinical results.

Platelet-Therapeutics to Improve Tissue Regeneration and Wound Healing-Physiological Background and Methods of Preparation.

Besides their function in primary hemostasis, platelets are critically involved in the physiological steps leading to wound healing and tissue repair. For this purpose, platelets have a complex set of receptors allowing the recognition, binding, and manipulation of extracellular structures and the detection of pathogens and tissue damage. Intracellular vesicles contain a huge set of mediators that can be released to the extracellular space to coordinate the action of platelets as other cell types for tissue repair. Therapeutically, the most frequent use of platelets is the intravenous application of platelet concentrates in case of thrombocytopenia or thrombocytopathy. However, there is increasing evidence that the local application of platelet-rich concentrates and platelet-rich fibrin can improve wound healing and tissue repair in various settings in medicine and dentistry. For the therapeutic use of platelets in wound healing, several preparations are available in clinical practice. In the present study we discuss the physiology and the cellular mechanisms of platelets in hemostasis and wound repair, the methods used for the preparation of platelet-rich concentrates and platelet-rich fibrin, and highlight some examples of the therapeutic use in medicine and dentistry.

A New, Conservative Treatment for Perianal Fistula that May Halve the Need for Surgical Intervention: Case Series.

In the last two decades, many sphincter preservation techniques have been proposed for the treatment of anal fistula. Since 2011, our surgical team has treated fistulas by sealing them with platelet-rich fibrin (PRF). This is performed actually as an outpatient process, without anaesthesia. Patients were treated with PRF sealant, during the period June 2012-March 2017. The fibrin preparation is applied in the fistulous tract, with no need for any type of anaesthesia, and so the patient can go home immediately afterwards, without further observation. After an average follow-up of 26.49 months, the perianal fistula had healed completely in 52.86% of the patients (n = 37), who each received an average of 1.92 sealant operations. In another 10 cases, the sealing was initially successful, but a relapse occurred during the follow-up period. The outpatient treatment of perianal fistula with PRF is totally harmless, is very low cost and achieves very acceptable results. In our opinion, therefore, this could be considered an appropriate initial treatment for perianal fistula, with surgical treatment being reserved if this approach is unsuccessful, thereby avoiding many complications and producing significant economic savings for the health system.

Impact of g force and timing on the characteristics of platelet-rich fibrin matrices

Recently, new centrifugation protocols for the preparation of platelet-rich fibrin (PRF) have been introduced in an attempt to further improve the beneficial impact of these 2nd generation platelet concentrate membranes. This in-vitro study aimed to compare the biological and physical characteristics of three types of PRF membranes using two different centrifuges with adapted relative centrifugal forces (RCF): leucocyte- and platelet-rich fibrin, advanced platelet-rich fibrin, and advanced platelet-rich fibrin+. Release of growth factors, macroscopic dimensions, cellular content and mechanical properties of the respective membranes, prepared from blood of the same individual were explored. Furthermore, the impact of timing (blood draw-centrifugation and centrifugation-membrane preparation) was assessed morphologically as well as by electron microscopy scanning. No statistically significant differences amongst the three PRF modifications could be observed, neither in their release of growth factors or the cellular content, nor in clot/membrane dimensions. The difference between both centrifuges were negligible when the same g-force was used. A lower g-force, however, reduced membrane tensile strength. Timing in the preparation process had a significant impact. Adaptation of RCF only had a minimal impact on the final characteristics of PRF membranes.

Platelet-Rich Fibrin, Preparation and Use in Dermatology.

The goal of these recommendations is to provide a framework to practitioners for implementing useful, evidence-based recommendations for the preparation of platelet-rich fibrin (PRF) and its use in various dermatological indications. The Indian Association of Dermatologists, Venereologists and Leprologists (IADVL) assigned the task of preparing these recommendations to its taskforce on platelet-rich plasma. A comprehensive literature search was done in the English language on the PRF across multiple databases. The grade of evidence and strength of recommendation was evaluated on the GRADE framework (Grading of Recommendation, Assessment, Development and Evaluation). A draft of clinical recommendations was developed on the best available evidence which was also scrutinized and critically evaluated by the IADVL Academy of Dermatology. Based on the inputs received, this final consensus statement was prepared. A total of 40 articles (meta-analyses, prospective and retrospective studies, reviews [including chapters in books] and case series) were critically evaluated and the evidence thus gathered was used in the preparation of these recommendations. This expert group recommends use of A-PRF+ protocol, that is (200 g for 8 min) for preparation of solid PRF and C-PRF protocol (700 g for 8 min) for liquid PRF. Swing out bucket model of centrifuge or the horizontal centrifuge is recommended for preparation of both PRF, and liquid PRF. Centrifugation must begin within 90–120 s of drawing of blood. PRF can be used in various indications for skin rejuvenation and nonhealing ulcers as either monotherapy or in combination with other therapies.

Comparison of surface microtopography and mechanodegradation characteristics of platelet-rich fibrin membranes using two different centrifugation protocols

Aim: To compare the surface microtopography and in vitro mechanodegradation characteristics of two different platelet-rich fibrin (PRF) preparation protocols, that is, leukocyte platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF). Materials and Methods: For the present ex vivo study, blood samples were obtained from 20 healthy volunteers, who were divided into two groups: group I (L-PRF) and group II (A-PRF). For each experiment, five samples each were used for obtaining L-PRF and A-PRF membranes. Surface microtopography was demonstrated by using light microscopic studies and scanning electron microscope (SEM) analysis. Mechanical characteristics were evaluated by using Universal Testing Machine and nano Triboindentor. Membrane degradation properties were studied by using the Bradford method. The data were expressed in mean and standard deviation (SPSS 20.0 version, USA). Intergroup statistical significance was assessed by using an unpaired t-test and defined significant as P < 0.05. Results: Light microscopic examinations and SEM analysis have demonstrated that the L-PRF membrane contained thick densely arranged fibers than the A-PRF membrane. Mechanical characteristics have revealed that the tensile strength was higher, and the breaking strain was lower in the L-PRF membranes as compared with A-PRF membranes. The degradation profile demonstrated that the A-PRF membrane takes a prolonged time for degradation as compared with L-PRF. Conclusion: The present study justifies that differences in the centrifugation protocol have an influence on the surface microtopography and mechanodegradation characteristics of the PRF membrane.

Mussel Adhesive Protein as a Promising Alternative to Fibrin for Scaffold Fixation during Cartilage Repair Surgery.

Fibrin has been used as a standard material for scaffold fixation during cartilage repair surgery. Most of the commercially available fibrin preparations need an additional method for scaffold fixation, most often with sutures, thus damaging the surrounding healthy cartilage. There is therefore a need to find alternatives to this method. In our study, we have investigated the potential possibility to use mussel adhesive protein as such an alternative. In this study, hydrophobic plastic was coated with the mussel adhesive protein Mefp-1 as well as with other cell adhesives (poly-lysine, fibronectin, and collagen). Human keratinocytes and chondrocytes were seeded on these substrates at 37°C in culture medium, followed by analysis of attachment and proliferation by crystal violet staining and metabolic labelling. Performance of Mefp-1 and fibrin as tissue glues were estimated by tensional force resistance measurement of moist porcine dermis (as a correlate to scaffold) glued to dermis, cartilage, or bone at 37°C. Mefp-1 supported maximal cell attachment at a coating density of approximately 1 µg/cm2. This was at least as good as the other adhesives tested. In addition, it supported cell proliferation at least as good as regular tissue culture plastic over a 7-day period. Measurement of tensional force resistance showed that Mefp-1 performed equally well as fibrin when porcine dermis was glued to cartilage and bone at the same concentration. Separation of the moist tissues after 15-minute incubation required a force of approximately 1 N/cm2 for both compounds. Mefp-1 show properties that qualify it as a compound that potentially could replace fibrin as a tissue glue for scaffold fixation. Given the possibilities to modify this protein by bioengineering, it is likely that the properties can be further improved.

Striking Differences in Platelet Distribution between Advanced-Platelet-Rich Fibrin and Concentrated Growth Factors: Effects of Silica-Containing Plastic Tubes.

Compared with platelet-rich plasma, the preparation of platelet-rich fibrin (PRF) is simple and has not been overly modified. However, it was recently demonstrated that centrifugation conditions influence the composition of PRF and that silica microparticles from silica-coated plastic tubes can enter the PRF matrix. These factors may also modify platelet distribution. To examine these possibilities, we prepared PRF matrices using various types of blood-collection tubes (plain glass tubes and silica-containing plastic tubes) and different centrifugation speeds. The protocols of concentrated growth factors and advanced-PRF represented high- and low-speed centrifugation, respectively. Platelet distribution in the PRF matrix was examined immunohistochemically. Using low-speed centrifugation, platelets were distributed homogeneously within the PRF matrix regardless of tube types. In high-speed centrifugation, platelets were distributed mainly on one surface region of the PRF matrix in glass tubes, whereas in silica-coated tubes, platelet distribution was commonly more diffusive than in glass tubes. Therefore, both blood-collection tube types and centrifugal conditions appeared to influence platelet distribution in the PRF matrix. Platelets distributed in the deep regions of the PRF matrix may contribute to better growth factor retention and release. However, clinicians should be careful in using silica-coated tubes because their silica microparticles may be a health hazard.

Influence of concentration and preparation of platelet rich fibrin on human bone marrow mononuclear cells (in vitro)

Large bone defects have always been a big challenge. The use of bone marrow mononuclear cells (BMCs) combined with an osteoconductive scaffold has been proved a good alternative for the treatment of large bone defects. Another autologous source for tissue engineering is platelet rich fibrin (PRF). PRF is a blood concentrate system obtained through a one-step centrifugation. The generated 3D matrix of the PRF clot serves as a reservoir of growth factors. Those growth factors might support the regenerative response of BMC, and therefore the effect of PRF, centrifuged with either high medium (208 g) or low (60 g) relative centrifugation force (RCF) on BMCs was evaluated in vitro in the present study. The two PRF matrices obtained were initially characterized and compared to human serum. Significantly increased concentrations of insulin-like growth factor (IGF), soluble intercellular adhesion molecule-1 (sICAM1) and transforming growth factor (TGF)-β were found in PRF compared to human serum whereas VEGF concentration was not significantly altered. A dose-response study revealed no further activation of BMC’s metabolic activity, if concentration of both PRF matrices exceeded 10% (v/v). Effect of both PRF preparations [10%] on BMC was analyzed after 2, 7, and 14 days in comparison to human serum [10%]. Metabolic activity of BMC increased significantly in all groups on day 14. Furthermore, gene expression of matrix metalloproteinases (MMP)-2, −7, and −9 was significantly stimulated in BMC cultivated with the respective PRF matrices compared to human serum. Apoptotic activity of BMC incubated with PRF was not altered compared to BMC cultivated with serum. In conclusion, PRF could be used as a growth factor delivery system of autologous or allogeneic source with the capability of stimulating cells such as BMC.