Injectable-platelet rich fibrin using the low speed centrifugation concept improves cartilage regeneration when compared to platelet-rich plasma

Novel approach to soft tissue regeneration: in vitro study of compound hyaluronic acid and horizontal platelet-rich fibrin combination

OBJECTIVE

This study aims to develop a compound biomaterial to achieve effective soft tissue regeneration.

METHODOLOGY

Compound hyaluronic acid (CHA) and liquid horizontal-platelet-rich fibrin (H-PRF) were mixed at a ratio of 1:1 to form a CHA-PRF gel. Human gingival fibroblasts (HGFs) were used in this study. The effect of CHA, H-PRF, and the CHA-PRF gel on cell viability was evaluated by CCK-8 assays. Then, the effect of CHA, H-PRF, and the CHA-PRF gel on collagen formation and deposition was evaluated by qRT‒PCR and immunofluorescence analysis. Finally, qRT‒PCR, immunofluorescence analysis, Transwell assays, and scratch wound-healing assays were performed to determine how CHA, H-PRF, and the CHA-PRF gel affect the migration of HGFs.

RESULTS

The combination of CHA and H-PRF shortened the coagulation time of liquid H-PRF. Compared to the pure CHA and H-PRF group, the CHA-PRF group exhibited the highest cell proliferation at all time points, as shown by the CCK-8 assay. Col1a and FAK were expressed at the highest levels in the CHA-PRF group, as shown by qRT‒PCR. CHA and PRF could stimulate collagen formation and HGF migration, as observed by fluorescence microscopy analysis of COL1 and F-actin and Transwell and scratch healing assays.

CONCLUSION

The CHA-PRF group exhibited greater potential to promote soft tissue regeneration by inducing cell proliferation, collagen synthesis, and migration in HGFs than the pure CHA or H-PRF group. CHA-PRF can serve as a great candidate for use alone or in combination with autografts in periodontal or peri-implant soft tissue regeneration.

The effect of injectable platelet rich fibrin as a nonsurgical treatment of the female stress urinary incontinence

PURPOSE

The complications of surgical treatments of stress urinary incontinence have led to the search for less invasive and safer treatment procedures. We aimed to investigate the efficacy of locally administered injectable platelet-rich fibrin (i-PRF), an autologous material that plays an important role in tissue regeneration, in women with stress urinary incontinence.

METHODS

Thirty-four women were included in this prospective, single-center, and interventional study, suffering from stress urinary incontinence refractory to conservative treatment. Three consecutive i-PRF injections were applied to the mid-urethra localization at anterior vaginal wall with an interval of 1 month. ICIQ-SF, UDI-6, IIQ-7 and POPDI-6 questionnaires were used to measure pre‑treatment, 1 month and 6 months post‑treatment symptom severity and the clinical outcomes were recorded.

RESULTS

The mean age of the patients was 51.5 ± 9.8 years. ICIQ-SF, UDI-6, IIQ-7 and POPDI-6 questionnaires results revealed significant clinical improvement of stress urinary incontinence severity afer the administration of i-PRF (p < 0.001). The results at 1 and 6 months after treatment did not change statistically significantly.

CONCLUSION

This study demonstrated that locally administiration of i-PRF is efective in relieving SUI symptoms with high success rates without any adverse effects reported. i-PRF injection may have the potential to be a novel, minimally invasive, and low-risk procedure, that could be an alternative and simple treatment modality to surgery for female patients with stress urinary incontinence. Additionally, it may create new avenues for research on therapeutic implementation of i-PRF.

Renewed Concept of Mastoid Cavity Obliteration with the Use of Temporoparietal Fascial Flap Injected by Injectable Platelet-Rich Fibrin after Subtotal Petrosectomy for Cochlear Implant Patients

Background: The subtotal petrosectomy procedure may be useful for cochlear implantation in selected patient groups. Although it is highly effective, complications can arise, which may have economic implications for the patient due to the high cost of the device. Therefore, several authors have attempted to identify the most effective concept for obliteration. Methods: We present a pilot descriptive study of application techniques for obliterating cavities after subtotal petrosectomy using a temporoparietal fascial flap (TPFF) modified with injectable platelet-rich fibrin (IPRF+) for three cochlear implant (CI) patients. Results: Our concept preserves important anatomical structures, such as the temporalis muscle, which covers the CI receiver-stimulator. Injection of IPRF+ also increases the available tissue volume for obliteration and enhances its anti-inflammatory and regenerative potential. Conclusions: To the best of our knowledge, the use of TPFF for filling the cavity has not been adopted for CI with SP and for blind sac closure. Our literature review and our experience with this small group of patients suggest that this procedure, when combined with IPRF+ injections, may reduce the risk of potential infection in the obliterated cavity, particularly when used with CI. This technique is applicable only in cases when the surgeons are convinced that the middle ear cavity is purged of cholesteatoma.

Ten years of injectable platelet-rich fibrin

The use of platelet-rich fibrin (PRF) has seen widespread advantages over platelet-rich plasma (PRP) in many fields of medicine. However, until 2014, PRF remained clinically available only in its solid clotted form. Modifications to centrifugation protocols and tube technology have led to the development of a liquid injectable version of PRF (i-PRF). This narrative review takes a look back at the technological developments made throughout the past decade and further elaborates on their future clinical applications. Topics covered include improvements in isolation techniques and protocols, ways to further concentrate i-PRF, and the clinical impact and relevance of cooling i-PRF. Next, various uses of i-PRF are discussed, including its use in regenerative periodontology, implantology, endodontics, temporomandibular joint injections, and orthodontic tooth movement. Furthermore, various indications in medicine are also covered, including its use in sports injuries and osteoarthritis of various joints, treatment of diabetic ulcers/wound care, and facial esthetics and hair regrowth. Finally, future applications are discussed, mainly its use as a drug delivery vehicle for small biomolecules, such as growth factors, antibiotics, exosomes, and other medications that may benefit from the controlled and gradual release of biomolecules over time.

Injectable platelet rich fibrin versus hyaluronic acid with bovine derived xenograft for alveolar ridge preservation. A randomized controlled clinical trial with histomorphometric analysis

BACKGROUND

Alveolar ridge preservation (ARP) is a technique that aims to maintain bone volume and minimize resorption after tooth extraction.

OBJECTIVE

This study aimed to compare the effectiveness of injectable platelet-rich fibrin (I-PRF) versus hyaluronic acid (HA) in combination with xenografts for ARP.

METHODS

This randomized controlled trial included 36 patients (20 females and 16 males) who required implant placement in the upper arch. The patients were randomly allocated to one of three groups (n = 12 each): I-PRF with xenografts, HA with xenografts, or xenografts alone. All patients underwent ARP, and the extraction sockets were sealed with a free gingival graft harvested from the palate, a total of 36 implants were inserted. Cone-beam CT scans were performed before and 4 months postoperatively to measure radiographic bone gain as the primary outcome. Clinical parameters, including soft tissue thickness and clinical bone width, were evaluated preoperatively, and at 4 months and 1 year postoperatively. Additionally, histological assessment of core bone biopsies was performed 4 months postoperatively using histomorphometric analysis to determine the percentages of newly formed bone, mature bone, and residual grafts.

RESULTS

Regarding the radiographic bone gain 4 months postoperative the HA group exhibited the highest value (9.78 ± 0.87), which was significantly greater than the values observed in the I-PRF and control groups (8.60 ± 1.27 and 7.99 ± 0.89, respectively) (one-way ANOVA, p = 0.007). Crestal bone loss was significantly higher in the control group (-0.98 ± 0.18) than in the I-PRF group (-0.53 ± 0.11) and HA group (-0.33 ± 0.15) groups (one-way ANOVA, p < 0.001). In the histomorphometric analysis, the mean area fraction of newly formed bone trabeculae was significantly higher in the HA group (56.66 ± 7.35) than in the I-PRF group (28.74 ± 5.15) and the control group (24.05 ± 3.64) (repeated measures ANOVA, p < 0.001). Additionally, the mean area fraction of residual graft material was higher in the I-PRF group (6.76 ± 2.59), followed by the control group (2.71 ± 1.24), while the HA group had the lowest value (2.63 ± 1.27) (Repeated measures ANOVA, p < 0.001).

CONCLUSION

The combination of HA with xenografts yielded better radiographic and histological outcomes in terms of new bone formation and degree of bone maturation than the I-PRF and control groups. Furthermore, I-PRF improved soft tissue thickness. Please note that clinical trial registration was not completed prior to participant recruitment and randomization. The registration link for this trial is https://clinicaltrials.gov/ct2/show/NCT05781529.

Applying additional autologous platelet-rich fibrin matrix or serial platelet-rich plasma to microfracture technique increases the quality of the repaired cartilage

PURPOSE

The aim of the present study is to investigate and compare the effects of biological adjuvants (platelet-rich plasma, platelet-rich fibrin matrix) and microfracture technique individually and in combination on full thickness chondral defects in a rabbit model.

METHODS

A total of 60 New Zealand White rabbits were randomly divided into six groups according to treatment modality as follows: control (C), microfracture (MF), platelet-rich plasma (PRP), platelet-rich fibrin matrix (PRFM), platelet-rich fibrin matrix after microfracture (MF + PRFM) and platelet-rich plasma after microfracture (MF + PRP) groups. The cartilage repair tissue was assessed histologically via International Cartilage Repair Score (ICRS) and macroscopically via ICRS macroscopic assessment scale.

RESULTS

It was shown that overall macroscopic scores of the groups with MF were higher than those of the groups without MF. The cell morphology observed in the defect areas was mostly characterized with non-chondrocyte cells in the groups without MF, whereas chondrocyte cells mostly prevailed in the groups with MF. There was a greater integration through the cartilage-like tissue in the MF + PRP and MF + PRFM groups. The control group showed either fissures or fissures partially filled with fibrous tissue. When the groups were individually examined, there were statistically significant differences between the control and MF groups (p = 0.002), between the control and MF + PRFM groups (p = 0.001), between the control and MF + PRP groups (p < 0.001), between the PRFM and MF + PRFM groups (p = 0.014) and between the PRFM and MF + PRP (p = 0.023) groups in terms of histological evaluation scores.

CONCLUSION

The application of PRP and PRFM in combination with MF treatment exhibited a positive impact on the repair and restoration of cartilage, and produced better outcomes than the individual use of PRP and PRFM. Nevertheless, in the treatment of full thickness chondral defects, the use of PRFM injection is recommended, which is performed intraoperatively at a single time and with no difficulty of repeating after surgery, instead of serial PRP injections based on the macroscopic and histological results obtained in the present study indicating that there was no significant difference between the use of these two adjuvants.

A Clinical Study of Platelet-Rich Fibrin Combined With Autologous High-Density Fat Transplantation in Augmentation Rhinoplasty

OBJECTIVE

This study was designed to analyze the clinical effect of autologous fat-granule transplantation in augmentation rhinoplasty and explore methods to improve the fat retention rate.

METHODS

A total of 70 enrolled patients were randomly divided into 2 groups: the platelet-rich fibrin (PRF) combined with high-density fat transplantation group (combined group) and the conventional fat-granule transplantation group (control group; n = 35 in each group). In the combined group, an appropriate amount of autologous fat was extracted and centrifuged, and the lower layer of high-density fat was taken and mixed with PRF isolated from whole blood for autotransplantation. In the control group, only fat was extracted and centrifuged for transplantation. The patients were followed up with for more than one year to observe the short- and long-term effects, complications, safety, and patient satisfaction.

RESULTS

Six months after the operation, the nasal shape was stable, the contour was higher and more stereoscopic than before, the average increase of nasal height was 3.0 mm in the combined group and 2.0 mm in the control group. No complications, such as fat embolism, infection, or necrosis occurred during the 1-year follow-up. The satisfaction rate between the 2 groups has statistical significance (P < .05).

CONCLUSION

Overall, PRF combined with autologous high-density fat transplantation is simple to perform, has a significantly increased fat-retention rate than the control group, and has stable long-term effects without obvious adverse reactions. A sufficient amount of fat and PRF transplantation can achieve a good orthopedic effect. Thus, this method can be widely used in clinical augmentation rhinoplasty.

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.

Effect of an intraoperative periradicular application of platelet-rich fibrin (PRF) on residual post-surgical neuropathic pain after disc herniation surgery: study protocol for NeuroPRF, a randomized controlled trial

BACKGROUND

The prevalence of post-surgical lumbar neuropathic radiculopathy is approximately 30%. Poor response to the recommended treatments for neuropathic pain, namely antidepressants and/or gabapentinoids, requires the development of new techniques to prevent chronic pain. One such well-tolerated technique is the administration of autologous plasma enriched in platelets and fibrin (PRF). This approach is largely used in regenerative medicine owing to the anti-inflammatory and analgesic properties of PRF. It could also be an interesting adjuvant to surgery, as it reduces neurogenic inflammation and promotes nerve recovery, thereby reducing the incidence of residual postoperative chronic pain. The aim of the present study is to evaluate the benefit of periradicular intraoperative application of PRF on the residual postsurgical neuropathic pain after disc herniation surgery.

METHODS

A randomized, prospective, interventional, controlled, single-blind study with evaluation by a blind outcome assessor will be performed in Strasbourg University Hospital. We will compare a control group undergoing conventional surgery to an experimental group undergoing surgery and periradicular administration of PRF (30 patients in each arm). The primary outcome is the intensity of postoperative neuropathic radicular pain, measured by a visual analog scale (VAS) at 6 months post-surgery. The secondary outcomes are the characteristics of neuropathic pain (NPSI), the quality of life (SF-12 and PGIC), the presence of anxiety/depression symptoms (HAD), and the consumption of analgesics. We will also carry out transcriptomic analysis of a panel of pro- and anti-inflammatory cytokines in blood samples, before surgery and at 6 months follow-up. These gene expression results will be correlated with clinical data, in particular, with the apparition of postoperative neuropathic pain.

DISCUSSION

This study is the first randomized controlled trial to assess the efficacy of PRF in the prevention of neuropathic pain following surgery for herniated disc. This study addresses not only a clinical question but will also provide information on the physiopathological mechanisms of neuropathic pain.

TRIAL REGISTRATION

This study is registered at ClinicalTrials.gov: NCT05196503 , February 24, 2022.

Osteochondral Regeneration Ability of Uncultured Bone Marrow Mononuclear Cells and Platelet-Rich Fibrin Scaffold

OBJECTIVES

Platelet-rich fibrin (PRF) and bone marrow mononuclear cells are potential scaffolds and cell sources for osteochondral regeneration. The main aim of this paper is to examine the effects of PRF scaffolds and autologous uncultured bone marrow mononuclear cells on osteochondral regeneration in rabbit knees.

MATERIALS AND METHODS

Three different types of PRF scaffolds were generated from peripheral blood (Ch-PRF and L-PRF) and bone marrow combined with uncultured bone marrow mononuclear cells (BMM-PRF). The histological characteristics of these scaffolds were assessed via hematoxylin-eosin staining, PicroSirius red staining, and immunohistochemical staining. Osteochondral defects with a diameter of 3 mm and depth of 3 mm were created on the trochlear groove of the rabbit's femur. Different PRF scaffolds were then applied to treat the defects. A group of rabbits with induced osteochondral defects that were not treated with any scaffold was used as a control. Osteochondral tissue regeneration was assessed after 2, 4, and 6 weeks by macroscopy (using the Internal Cartilage Repair Society score, X-ray) and microscopy (hematoxylin-eosin stain, safranin O stain, toluidine stain, and Wakitani histological scale, immunohistochemistry), in addition to gene expression analysis of osteochondral markers.

RESULTS

Ch-PRF had a heterogeneous fibrin network structure and cellular population; L-PRF and BMM-PRF had a homogeneous structure with a uniform distribution of the fibrin network. Ch-PRF and L-PRF contained a population of CD45-positive leukocytes embedded in the fibrin network, while mononuclear cells in the BMM-PRF scaffold were positive for the pluripotent stem cell-specific antibody Oct-4. In comparison to the untreated group, the rabbits that were given the autologous graft displayed significantly improved healing of the articular cartilage tissue and of the subchondral bone. Regeneration was gradually observed after 2, 4, and 6 weeks of PRF scaffold treatment, which was particularly evident in the BMM-PRF group.

CONCLUSIONS

The combination of biomaterials with autologous platelet-rich fibrin and uncultured bone marrow mononuclear cells promoted osteochondral regeneration in a rabbit model more than platelet-rich fibrin material alone. Our results indicate that autologous platelet-rich fibrin scaffolds combined with uncultured bone marrow mononuclear cells applied in healing osteochondral lesions may represent a suitable treatment in addition to stem cell and biomaterial therapy.

Does the Use of Injectable Platelet-Rich Fibrin After Arthrocentesis for Disc Displacement Without Reduction Improve Clinical Outcomes?

PURPOSE

Many studies have reported the role of arthrocentesis to alleviate symptoms of patients with disc displacement without reduction (DDWoR). Nevertheless, the benefit of injectable platelet-rich fibrin (i-PRF) remains unclear. The aim of this study was to answer the following question: among patients with DDWoR, do those treated with intra-articular injection of i-PRF after arthrocentesis, when compared to those treated with arthrocentesis only, have better clinical outcomes in terms of pain reduction and improvement of jaw movement?

MATERIALS AND METHODS

This single-blind randomized, controlled study included patients with diagnosed DDWoR, in the Department of Oral and Maxillofacial Surgery at the School of Dentistry, Ege University, who had localized joint pain and limited range of motion. Patients were treated either with arthrocentesis (AC group) or arthrocentesis in combination with intra-articular i-PRF injection (AC + i-PRF group). The predictor variable was treatment (ie, arthrocentesis with or without i-PRF). The primary outcome variable was pain (visual analog scale). The secondary outcome variables were maximum mouth opening, lateral and protrusive movements. Outcome variables were recorded at pretreatment and at the postoperative 1st, 2nd, 3rd, 6th, and 12th months. Statistical analysis was performed using the Brunner-Langer model, with a significance level P < .05.

RESULTS

This study comprised 76 patients (34 females/4 males, mean age 47.2 ± 9.1 for the AC + i-PRF group; 35 females/3 males, mean age 46.8 ± 10.2 for the AC group). The treatment success rate was 73.7% for the AC group and 100% for the AC + i-PRF group (P = .012). Pain levels in the AC + i-PRF group were found to decrease more than the AC group over 12 months postoperatively (palpation: -6.9 ± 1.2 vs -5.3 ± 1.3; chewing: -6.9 ± 1.5 vs -5.1 ± 1.7; jaw movements: -6.9 ± 1.1 vs -5.1 ± 1.4). This difference was statistically significant (P < .001). The degree of jaw movement in the AC + i-PRF group was found to increase more than the AC group over 12 months postoperatively (maximum mouth opening: 8.0 ± 2.1 vs 4.9 ± 2.0; contralateral: 1.8 ± 0.8 vs 0.2 ± 1.0; ipsilateral: 2.9 ± 1.3 vs 0.8 ± 1.5; protrusive: 2.6 ± 1.1 vs 0.8 ± 1.3). This difference was statistically significant (P < .001).

CONCLUSION

Intra-articular injection of i-PRF after arthrocentesis produced greater improvements in pain reduction and jaw movement when compared to arthrocentesis only. These results indicate that i-PRF used in combination with arthrocentesis is an effective adjunctive treatment.

Cartilage Injury Repair by Human Umbilical Cord Wharton's Jelly/Hydrogel Combined with Chondrocyte

Purpose: There is still a lack of effective treatments for cartilage damage. Cartilage tissue engineering could be a promising treatment method. Human umbilical cord Wharton's jelly (HUCWJ) and hydrogels have received wide attention as a scaffold for tissue engineering. They have not been widely used in clinical studies as their effectiveness and safety are still controversial. This study systematically compared the ability of these two biological tissue engineering materials to carry chondrocytes to repair cartilage injury in vivo. Methods: Chondrocytes were cocultured with HUCWJ or hydrogel for in vivo transplantation. The treatments comprised the HUCWJ+cell, hydrogel+cell, and blank groups. A rabbit model with articular cartilage defect in the knee joint area was established. The defective knee cartilage of different rabbit groups was treated for 3 and 6 months. The efficacy of the various treatments on articular cartilage injury was evaluated by immunohistochemistry and biochemical indices. Results: We found that the HUCWJ+cell and hydrogel+cell groups promoted cartilage repair compared with the blank group, which had no repair effect. The treatment efficacy of each group at 6 months was significantly better than that at 3 months. HUCWJ showed accelerated cartilage repair ability than the hydrogel. Conclusion: This study showed that HUCWJ is useful in cartilage tissue engineering to enhance the efficacy of chondrocyte-based cartilage repair, providing new insights for regenerative medicine. Impact statement Human umbilical cord Wharton's jelly (HUCWJ) and hydrogel are the suitable extracellular matrix for cartilage tissue engineering. This study assessed the capacity of HUCWJ- and hydrogel-loaded chondrocytes to repair cartilage injury in vivo. The data demonstrate that both HUCWJ and hydrogel effectively facilitated cartilage repair, and the repair effects of HUCWJ were significantly better compared with hydrogel, therefore providing a potential candidate for clinical practice of cartilage regeneration therapy.

The effect of submucosal injection of platelet-rich fibrin vs. platelet-rich plasma on orthodontic tooth movement in rabbits; 28 days follow-up

OBJECTIVE

This study aimed to compare between the effects of submucosal injection of platelet rich fibrin (i-PRF) versus platelet rich plasma (PRP) on orthodontic tooth movement (OTM) in a rabbit model over a 28-day follow-up period.

MATERIALS AND METHODS

Sixty-three rabbits were assigned into 3 equal groups. Group I animals were subjected to the OTM without any treatments and considered as the control. Whereas groups II and III were handled as group I and instead i-PRF and PRP were injected submucosally in the buccal vestibular mucosa next to the mandibular 1st premolar, respectively. The distance of OTM was consecutively measured clinically after 7, 14 and 28 days. Seven rabbits from each group were euthanized after 7, 14 and 28 days for histological evaluation. Two-way ANOVA followed by LSD post-hoc statistical tests were used for comparison.

RESULTS

After 28 days, the mean tooth movements were 4.36±0.04mm in the control group, 6.30±0.06mm in the group receiving PRP and, 6.85±0.09mm in the group receiving i-PRF. Statistical analysis for the values of teeth movements revealed highly significant differences between different groups (P=0.001) and between different time periods (P=0.001). Histological analysis showed that submucosal injection of PRP and i-PRF yielded significant differences in periodontal ligament width in compression and tension sides between different groups (P=0.001) and between different time periods (P=0.001).

CONCLUSION

Submucosal injection of either PRP or i-PRF is a minimally invasive and safe approach for accelerating OTM. In this rabbit model, the effect of i-PRF is significantly more pronounced than the effect of PRP.

Evolution and Clinical Advances of Platelet-Rich Fibrin in Musculoskeletal Regeneration

Over the past few decades, various forms of platelet concentrates have evolved with significant clinical utility. The newer generation products, including leukocyte-platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF), have shown superior biological properties in musculoskeletal regeneration than the first-generation concentrates, such as platelet-rich plasma (PRP) and plasma rich in growth factors. These newer platelet concentrates have a complete matrix of physiological fibrin that acts as a scaffold with a three-dimensional (3D) architecture. Further, it facilitates intercellular signaling and migration, thereby promoting angiogenic, chondrogenic, and osteogenic activities. A-PRF with higher leukocyte inclusion possesses antimicrobial activity than the first generations. Due to the presence of enormous amounts of growth factors and anti-inflammatory cytokines that are released, A-PRF has the potential to replicate the various physiological and immunological factors of wound healing. In addition, there are more neutrophils, monocytes, and macrophages, all of which secrete essential chemotactic molecules. As a result, both L-PRF and A-PRF are used in the management of musculoskeletal conditions, such as chondral injuries, tendinopathies, tissue regeneration, and other sports-related injuries. In addition to this, its applications have been expanded to include the fields of reconstructive cosmetic surgery, wound healing in diabetic patients, and maxillofacial surgeries.

Evaluation of injectable platelet-rich fibrin effect on the rate of canine retraction and alkaline phosphatase levels: An in-vivo study

INTRODUCTION

With time, the treatment protocol has changed, and currently, there is a new school of treatment called accelerated orthodontics, wherein the goal is to shorten the time. In this study, a liquid formulation of platelet-rich fibrin such as injectable platelet-rich fibrin (i-PRF), was used, and its effect on the rate of canine retraction and the crevicular alkaline phosphatase (ALP) levels were studied.

METHODS

Thirteen patients were recruited for this study with a mean age of 20.6 ± 3.2 years. A split-mouth type of study design was used in which the maxillary arch of each subject was divided into an experimental and control group. I-PRF was injected in the labial and lingual attached gingiva of the canine in the experimental group. The gingival crevicular fluid collection was done from the distal aspect of the canine before canine retraction, 24 hours after retraction, and 28 days after retraction from both sites (ie, control and experimental sites). ALP activity was analyzed using a semiautomated analyzer, and the rate of canine retraction was measured on stone casts with the help of a digital vernier caliper.

RESULTS

The individual canine retraction was 1.8-fold faster in the i-PRF group than in the control group. The ALP activity was significantly greater at 24 hrs and 28 days after retraction in the experimental group.

CONCLUSIONS

These results suggest that i-PRF is an innovative, noninvasive approach to accelerating tooth movement. ALP activity in gingival crevicular fluid reflects the biological changes in the periodontium, and the steep increase in the activity indicates increased bone remodeling within the experimental group.

Effect of Injectable Platelet-Rich Fibrin with a Nano-Hydroxyapatite Bone Graft on the Treatment of a Grade II Furcation Defect

Background: Periodontal diseases lead to bone loss, crestal defects and even loss of the tooth, which also further makes it difficult to replace the tooth. Autogenous bone grafts are considered the gold standard in bone regenerative procedures. This study aimed to compare and evaluate the bone regenerative effects of i-PRF (Injectable- Platelet-rich fibrin) with a bone graft and a bone graft alone in mandibular grade II furcation defects over a period of 9 months. Method: This was a comparative study of 12 participants, who were randomly selected and grouped into two groups: test and control. Following phase I therapy, both groups were subjected to open flap debridement. In the test group, after debridement, a nano-hydroxyapatite bone graft mixed with i-PRF was inserted, whereas in the control group only a nano-hydroxyapatite bone graft was inserted. The clinical parameters such as plaque index (PI), gingival index (GI), pocket probing depth (PPD), clinical attachment level (CAL), horizontal probing depth (HPD) and vertical probing depth (VPD) were recorded at baseline, 3 months, 6 months and 9 months following the surgery. The bone area fill (BAF) was assessed using intraoral periapical radiographs (IOPARs) taken at baseline and 9 months after surgery. Results: At the baseline, there was no statistically significant difference between the tested parameters. After 9 months all the clinical parameters, PI, GI, PPD, CAL, HPD and VPD as well as radiographic bone fill showed a significant increase in both the groups (p < 0.05) (PI-TGr; CGr−VPD—3.5 ± 0.54 to 0.66 ± 0.51; 3.3 ± 0.81 to 2 ± 0.63/BAF—2.9 ± 0.88 to 5.6 ± 1.10; 3.4 ± 1.39 to 3.9 ± 1.4). On comparison the test group showed better results for each clinical parameter. Conclusion: The results showed increased improvement in clinical conditions in both groups, although better results were seen in the group where i-PRF with a nano-HA bone graft was used in the furcation defect.

Injectable platelet-rich fibrin as treatment for temporomandibular joint osteoarthritis: A randomized controlled clinical trial

The purpose of this study was to assess the treatment outcomes of intraarticular injection of injectable platelet-rich fibrin (i-PRF) after arthrocentesis in patients with temporomandibular joint osteoarthritis (TMJ-OA). Patients were randomly assigned to one of two treatment groups: those who received intraarticular injection of i-PRF after arthrocentesis procedure - the i-PRF group; and those who underwent the arthrocentesis procedure alone - the control group. The primary outcome variable was pain, the level of which was measured preoperatively and at 1, 2, 3, 6, and 12 months postoperatively. The secondary outcome variables included maximum mouth opening (MMO), and lateral and protrusive movements. Of the total of 36 patients, 18 were analyzed in the i-PRF group and 18 in the control group. There were significant differences between the groups in terms of pain levels and measurements of MMO, lateral movement, and protrusive movement over the 12 months of follow-up (p < 0.001). Significant increases in pain levels and decreases in measurements of MMO, lateral movement, and protrusive movement were observed in the control group from the 6th to 12th month postoperatively (p < 0.001). In contrast, no significant differences were found in both pain levels and measurements of MMO, lateral, and protrusive movements for the i-PRF group from the 2nd to the 12th month postoperatively. Within the limitations of the study it seems that intraarticular injection of i-PRF after arthrocentesis should be preferred whenever appropriate because when reducing pain intensity and improving functional jaw movement is the priority.

Utilizing 3D bioprinted platelet-rich fibrin-based materials to promote the regeneration of oral soft tissue

Oral soft tissue defects remain difficult to treat owing to the limited efficacy of available treatment materials. Although the injectable platelet-rich fibrin (i-PRF) is a safe, autologous source of high levels of growth factors that is often employed to promote the regeneration of oral soft tissue, its effectiveness is restrained by difficulties in intraoperative shaping together with the burst-like release of growth factors. We herein sought to develop a bioactive bioink composed of i-PRF, alginate and gelatin capable of promoting the regeneration of the oral soft tissue. This bioink was successfully applied in 3D bioprinting and exhibited its ability to be shaped to individual patient needs. Importantly, we were also able to significantly prolong the duration of multiple growth factors release as compared to that observed for i-PRF. The growth factor bioavailability was further confirmed by the enhanced proliferation and viability of printed gingival fibroblasts. When deployed in vivo in nude mice, this bioink was further confirmed to be biocompatible and to drive enhanced angiogenic activity. Together, these data thus confirm the successful production of an i-PRF-containing bioink, which is suitable for the individualized promotion of the regeneration of oral soft tissue.

The feasibility of injectable PRF (I-PRF) for bone tissue engineering and its application in oral and maxillofacial reconstruction: From bench to chairside

Among all the biomaterials introduced in the field of bone tissue engineering, injectable platelet-rich fibrin (I-PRF) has recently gained considerable attention. I-PRF, as a rich source of biologically active molecules, is a potential candidate which can be easily obtained in bedside and constitutes several biological factors which can result in higher anti-bacterial, anti-inflammatory and regenerative capabilities. According to the studies evaluating the osteogenic efficacy of I-PRF, this biomaterial has exhibited favorable outcomes in terms of adhesion, differentiation, migration, proliferation and mineralization potential of stem cells. In addition, the injectability and ease-of-applicability of this biomaterial has led to its various clinical applications in the oral and maxillofacial bone regeneration such as ridge augmentation, sinus floor elevation, cleft palate reconstruction and so on. Furthermore, to enhance the clinical performance of I-PRF, albumin gel-PRF as a long-lasting material for long-term utilization has been recently introduced with a gradual increase in growth factor release pattern. This review provides a comprehensive approach to better evaluate the applicability of I-PRF by separately appraising its performance in in-vitro, in-vivo and clinical situations. The critical approach of this review toward the different production protocols and different physical and biological aspects of I-PRF can pave the way for future studies to better assess the efficacy of I-PRF in bone regeneration.

Treatment of temporomandibular joint disc displacement using arthrocentesis combined with injectable platelet rich fibrin versus arthrocentesis alone

Background/purpose

Temporomandibular joint disc displacement is the most frequently reported temporomandibular disorder that may severely impair quality of life and can be challenging to treat. This study aimed to evaluate and compare the efficiency of intra-articular injection of injectable platelet rich fibrin (i-PRF) following arthrocentesis or arthrocentesis alone in treatment of patients with TMJ disc displacement with reduction.

Materials and methods

Forty patients for a total of forty joints with reducible anterior disc displacement, as confirmed by Magnetic Resonance Imaging (MRI) were selected and divided into 2 equal groups. In group I (control group), arthrocentesis alone was performed with Ringer solution. In group II (study group), a combination of arthrocentesis and intra-articular injection with 1.5 ml i-PRF was performed. The outcome variables included pain intensity evaluated with a visual analogue scale, inter-incisal opening, lateral movement evaluated in millimeters, and clicking. Assessments were done pre-operatively, and 1 week, 3 months, and 6 months postoperatively.

Results

There was statistically significant reduction in pain intensity and clicking sound and increase in mouth opening and lateral movement in i-PRF group when compared to arthrocentesis group. In addition, the differences between preoperative and postoperative status in all the measured parameters were statistically significant within the study and the control group throughout the postoperative period.

Conclusion

The combination of i-PRF with arthrocentesis is a safe and effective method in the treatment of TMJ disc displacement with reduction.

Systematic Review of Platelet-Rich Plasma for Rotator Cuff Repair: Are We Adhering to the Minimum Information for Studies Evaluating Biologics in Orthopaedics?

Background

The therapeutic efficacy of orthobiologic therapies for rotator cuff repair is difficult to evaluate owing to reporting inconsistences. In response, the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) guidelines were developed to ensure standard reporting on orthobiologic therapies.

Purpose

To systematically review clinical studies evaluating platelet-rich plasma (PRP) for full-thickness rotator cuff repair and adherence to MIBO guidelines.

Study Design

Scoping review; Level of evidence, 4.

Methods

A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, EMBASE, and the Cochrane Library databases. Inclusion criteria were clinical studies reporting on rotator cuff tears (≥1 cm) surgically repaired with PRP. Patient demographics, biologic intervention, and adherence to the MIBO guidelines were systematically reviewed.

Results

A total of 19 studies (1005 patients) were included in this review. Across all studies, 58.5% of the MIBO checklist items for PRP were reported. Out of 47 checklist items, 19 were reported in over 85% of studies, whereas 22 were reported in less than half of studies. Details of whole-blood processing and characteristics, as well as PRP processing and characteristics, were reported inconsistently, and no study provided adequate information to enable the precise replication of preparation protocols for PRP.

Conclusion

This systematic review highlights the current reporting deficiencies within the scientific literature of important variables for evaluating PRP for full-thickness rotator cuff repair. There was widespread variability among published studies that evaluate PRP for this application and, more specifically, studies were limited by inconsistent universal reporting of whole-blood and PRP processing and postprocessing characteristics. To improve our understanding of biologic efficacy and to promote repeatability, stricter adherence to the MIBO guidelines is necessary. We propose that the checklist limitations be addressed and that modification of the MIBO guidelines be considered to improve the reporting of individual components within certain categories.

Injectable platelet rich fibrin facilitates hair follicle regeneration by promoting human dermal papilla cell proliferation, migration, and trichogenic inductivity

Hair follicle regeneration has been successful in mice but failed in human being for years. Dermal papilla cells, a specialized mesenchymal stem cell derived from dermal papilla within hair follicles, is considered the key cells for hair follicle regeneration function as both regeneration initiator and regulator. Injectable platelet rich fibrin (i-PRF), a novel biomaterial rich in a variety of growth factors and three-dimensional scaffolds, has shown promising effects on tissue regeneration. In this study, we aimed to evaluate the application of i-PRF in human hair follicle regeneration by examining the biological effects of i-PRF on human dermal papilla cells (hDPCs). Biomaterial compatibility, cell viability, proliferation, migration, alkaline phosphatase activity and trichogenic inductivity were assessed after exposing hDPCs to different concentrations of i-PRF extracts. In addition, we investigated the ultrastructure of i-PRF with all cell components filtered. The results revealed that i-PRF possessing excellent biocompatibility and could significantly promote hDPCs proliferation, migration, and trichogenic inductivity. Furthermore, the concentration of i-PRF is able to remarkably influence hDPCs behavior in a dose-dependent pattern. Different concentrations exhibited differential effects on hDPCs behavior. In general, lower concentration promotes cell proliferation better than higher concentration, while higher concentration promotes cell function better reversely. Best concentration for hDPCs in vitro expending is 1% concentration. 20% concentration is optimal for hair follicle regeneration. In summary, our findings concluded that i-PRF facilitates hair follicle regeneration by promoting human dermal papilla cell proliferation, migration, and trichogenic inductivity.

Second generation liquid platelet concentrates: A literature review

Liquid or injectable platelet rich fibrin (PRF) is a second-generation platelet concentrate which is completely autologous and free of external additives like bovine thrombin and calcium chloride. Additionally, it is the only one to be obtained in a liquid form among the second generation platelet concentrates. This allows for wide applications such as to maximize injections or mixing with biomaterials such as bone grafts or antibiotics. Since it was first introduced in 2015, several modifications of the original protocol have been proposed which aim at maximizing its biological and mechanical properties. This includes changes in centrifugation speed, time, and so on. The aim of this review is to summarize the various modifications of the injectable/liquid formation of PRF as well as to discuss the potential applications and future research direction.

Injectable platelet-rich fibrin influences the behavior of gingival mesenchymal stem cells

In this study, we examined the effects of injectable platelet-rich fibrin (iPRF) on proliferation and osteodifferentiation in mesenchymal stem cells (MSCs) isolated from human gingiva. Gingival MSCs (gMSCs) were grown in experimental culture media with different concentrations of iPRF [5%, 10%, and replacement of fetal calf serum (FCS) in the standard media with 10% iPRF–10% iPRF-FCS]. Immunophenotyping of gMSCs was performed after seven days by flow cytometry, and their proliferation was examined after three and seven days using the Cell Counting Kit-8 method. After 14 days in culture, spontaneous osteogenic differentiation of gMSCs was evaluated via real-time polymerase chain reaction. All gMSCs were positive for cluster of differentiation (CD) 105, CD73, CD90, and CD44, and negative for CD34/45, CD14, CD79a, and human leukocyte antigen, DR isotype (HLA-DR). Reduced expression of some surface antigens was observed in the gMSCs grown in 10% iPRF-FCS medium compared to the other groups. After three days, gMSCs grown in 10% iPRF had proliferated significantly less than the other groups. After seven days, proliferation was significantly higher in the 5% iPRF cells compared to the control, while proliferation in the 10% iPRF and 10% iPRF-FCS groups was significantly lower. No spontaneous osteogenic differentiation was observed in the presence of iPRF, as observed by low runt-related transcription factor 2 (RUNX2) expression. Some expression of secreted protein acidic and cysteine rich (SPARC) and collagen 1 alpha (COL1A) was observed for all the gMSCs regardless of the culture medium composition. gMSCs grown in 10% iPRF had significantly lower SPARC expression. In conclusion, 5% iPRF stimulated gMSC proliferation, and an excessively high concentration of iPRF can impair osteogenic induction.

The efficacy of intra-articular injectable platelet-rich fibrin application in the management of Wilkes stage III temporomandibular joint internal derangement

The aim of this retrospective study was to compare the effectiveness of hyaluronic acid (HA) and injectable platelet-rich fibrin (i-PRF) in the management of Wilkes stage III internal derangement, and to evaluate the biosupplementation capacity of i-PRF. The records of all 54 relevant patients with Wilkes stage III internal derangement confirmed by magnetic resonance imaging and treated with arthrocentesis alone or in combination with HA or i-PRF were selected. The outcome variables were pain intensity at rest (VASr) and in function (VASf), evaluated with a visual analogue scale, and maximum mouth opening (MMO), evaluated in millimetres; assessments were made preoperatively, immediately after the procedure, and at 1 week, 1 month, and 3 months postoperatively. When compared to the HA and arthrocentesis groups, the i-PRF group showed significantly better improvements in MMO at 1 and 3 months (P=0.024 and P=0.006, respectively), VASr at 1 and 3 months (both P<0.001), and VASf at 1 week (P=0.019) and 1 and 3 months (both P<0.001) postoperatively. In all groups, better MMO, VASr, and VASf values were observed compared to the preoperative status. The application of i-PRF after arthrocentesis is more effective than arthrocentesis alone or with HA in the short term. HA was found not to provide significant additional benefits over arthrocentesis alone.

Activation of Human Osteoblasts via Different Bovine Bone Substitute Materials With and Without Injectable Platelet Rich Fibrin in vitro

Introduction

The aim of the in vitro study was to compare the effect of four bovine bone substitute materials (XBSM) with and without injectable platelet-reach fibrin for viability and metabolic activity of human osteoblasts (HOB) as well as expression of alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP-2), and osteonectin (OCN).

Materials and Methods

Cerabone^® (CB), Bio-Oss^® (BO), Creos Xenogain^® (CX) and MinerOss^® X (MO) ± i-PRF were incubated with HOB. At day 3, 7, and 10, cell viability and metabolic activity as well as expression of ALP, OCN, and BMP-2, was examined.

Results

For non-i-PRF groups, the highest values concerning viability were seen for CB at all time points. Pre-treatment with i-PRF increased viability in all groups with the highest values for CB-i-PRF after 3 and 7 and for CX-i-PRF after 10 days. For metabolic activity, the highest rate among non-i-PRF groups was seen for MO at day 3 and for CB at day 7 and 10. Here, i-PRF groups showed higher values than non-i-PRF groups (highest values: CB + i-PRF) at all time points. There was no difference in ALP-expression between groups. For OCN expression in non-i-PRF groups, CB showed the highest values after day 3, CX after day 7 and 10. Among i-PRF-groups, the highest values were seen for CX + i-PRF. At day 3, the highest BMP-2 expression was observed for CX. Here, for i-PRF groups, the highest increase was seen for CX + i-PRF at day 3. At day 7 and 10, there was no significant difference among groups.

Conclusion

XBSM sintered under high temperature showed increased HOB viability and metabolic activity through the whole period when compared to XBSM manufactured at lower temperatures. Overall, the combination of XBSM with i-PRF improved all cellular parameters, ALP and BMP-2 expression at earlier stages as well as OCN expression at later stages.

The Influence of Different Guided Bone Regeneration Procedures on the Contour of Bone Graft after Wound Closure: A Retrospective Cohort Study

The aim of this study was to evaluate the impact of different guided bone regeneration (GBR) procedures on bone graft contour after wound closure in lateral ridge augmentation. A total of 48 patients with 63 augmented sites were included in this study. Participants were divided into 4 groups (n = 12 in each group) based on different surgical procedures: group 1: particulate bone substitute + collagen membrane; group 2: particulate bone substitute + collagen membrane + healing cap, group 3: particulate bone substitute + injectable platelet-rich fibrin (i-PRF) + collagen membrane; group 4: particulate bone substitute + i-PRF + surgical template + collagen membrane. After wound closure, the thickness of labial graft was measured at 0–5 mm apical to the implant shoulder (T0–T5). At T0–T2, the thickness of labial graft in group 4 was significantly higher than the other three groups (p < 0.05). And group 4 showed significantly more labial graft thickness than group 1 and group 2 at T3–T5 (p < 0.05). Within the limitations of this study, the use of i-PRF in combination with the surgical template in GBR may contribute to achieving an appropriate bone graft contour after wound closure.

Red and Yellow Injectable Platelet-Rich Fibrin Demonstrated Differential Effects on Periodontal Ligament Stem Cell Proliferation, Migration, and Osteogenic Differentiation

The biological benefits of using two fractions derived from injectable platelet-rich fibrin (i-PRF) in bone regeneration remain unclear. Thus, the current study examined two fractionation protocols producing yellow i-PRF and red i-PRF on periodontal ligament stem cells (PDLSCs). The i-PRF samples from five donors were harvested from two different levels, with and without a buffy coat layer, to obtain red and yellow i-PRF, respectively. The PDLSCs were isolated and characterized before their experimental use. The culture medium in each assay was loaded with 20% of the conditioned medium containing the factors released from the red and yellow i-PRF. Cell proliferation and cell migration were determined with an MTT and trans-well assay, respectively. Osteogenic differentiation was investigated using alkaline phosphatase and Alizarin red staining. The efficiency of both i-PRFs was statistically compared. We found that the factors released from the red i-PRF had a greater effect on cell proliferation and cell migration. Moreover, the factors released from the yellow i-PRF stimulated PDLSC osteogenic differentiation earlier compared with the red i-PRF. These data suggest that the red i-PRF might be suitable for using in bone regeneration because it induced the mobilization and growth of bone regenerative cells without inducing premature mineralization.

Allogeneic Fibrin Clot for Odontogenic/Cementogenic Differentiation of Human Dental Mesenchymal Stem Cells

BACKGROUND

Fetal bovine serum is widely used as a growth supplement for cell culture medium; however, animal-borne pathogens increase the risk of transmitting infectious agents. Platelet-rich fibrin is recently considered as a successful alternative but leukocytes present limits to its allogeneic feasibility. The aim of this study was to explore the effects of allogeneic fibrin clot (AFC) without leukocytes on inducing odontogenic/cementogenic differentiation of human dental pulp stem cells (hDPSCs) and human periodontal ligament stem cells (hPDLSCs) in vitro and in vivo.

METHODS

AFC was prepared by high-speed centrifugation and leukocytes were almost removed, and AFC serum was obtained through three freeze-thaw cycles. hDPSCs and hPDLSCs were treated with AFC serum to investigate the odontogenic or cementogenic associated markers by real-time polymerase chain reaction. hDPSCs were treated with AFC serum and placed inside of dentin canal, hPDLSCs were treated with AFC serum to wrap outside of dentin, the mixture was then transplanted into the subcutaneous of nude mice for 12 weeks.

RESULTS

AFC serum exhibited enough growth factors and cytokines to induce odontogenic/cementogenic differentiation of hDPSCs and hPDLSCs in vitro. Furthermore, AFC seurum could induce hDPSCs to differentiate into odontoblasts-like cells and pulp-like tissues, and hPDLSCs to regenerate cementum-like tissues.

CONCLUSION

AFC could be an alternative safe source with growth factors for the expansion of human dental mesenchymal stem cells (hDMSCs).

Liquid platelet-rich fibrin promotes the regenerative potential of human periodontal ligament cells

OBJECTIVE

To compare the biological effect of PRP and liquid-PRF on human periodontal ligament cells (hPDLCs) in vitro.

METHODS

The liquid-PRF was processed with centrifugation at 700 g for 3 min, and PRP was processed according to Curasan's protocol. Migration and proliferation assay were performed by a scratch/Transwell assay and a CCK-8 assay, respectively. To investigate hPDLC differentiation, alkaline phosphatase (ALP) assay, Alizarin Red S staining, and gene expression level detection of Runx2, Col1a1, and OCN were conducted. Furthermore, cells cultured with lipopolysaccharide (LPS) to induce an inflammation condition were utilized to investigate the impact of liquid-PRF on inflammatory resolution.

RESULTS

Either PRP or liquid-PRF can promote proliferation, migration of hPDLCs, and osteogenic differentiation of hPDLCs. It was noteworthy that liquid-PRF demonstrated a significantly higher ability to promote the biological differentiation and mineralization of hPDLCs compared with PRP. Lastly, when hPDLCs were incubated with LPS, cells cultured with liquid-PRF showed significantly lower mRNA expression levels of inflammatory genes.

CONCLUSIONS

Liquid-PRF notably promoted hPDLC activity and attenuated the inflammatory state induced by LPS.

A Comprehensive Review of Concentrated Growth Factors and Their Novel Applications in Facial Reconstructive and Regenerative Medicine

BACKGROUND

Concentrated growth factors (CGFs) are the latest generation of platelet concentrates. The objective of developing CGF is to increase therapeutic efficacy. However, few studies have supported the superiority of CGF in composition and efficacy. The reconstruction and regeneration process is complicated and long term, whereas bioactivity of CGF is not durable. The purpose of this review is threefold. The first is to recommend more comparative studies between CGF and other platelet concentrates. The second is to constitute a continuous drug delivery system by combining CGF with other biomaterials. Finally, the novel use of CGF in facial regenerative and reconstructive medicine will be highlighted.

METHODS

A comprehensive review of literature regarding the use of CGF in facial regenerative and reconstructive medicine was performed. Based on the inclusion and exclusion criteria, a total of 135 articles were included.

RESULTS

The use of CGF involving facial rejuvenation, cartilage grafting, facial bone defects, facial peripheral nerve injury and wounding is reviewed. The reconstructive and regenerative principles lie in firm fibrin scaffolds and continuous in situ delivery of multiple growth factors.

CONCLUSIONS

CGF represents an advance in personalized medicine concept. However, the current scientific evidences about the use of CGF are limited. More basic and clinical studies should be conducted to understand the characteristics and clinical application of CGF.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Comparison of the Efficiacy of Intra-Articular Injection of Liquid Platelet-Rich Fibrin and Hyaluronic Acid After in Conjunction With Arthrocentesis for the Treatment of Internal Temporomandibular Joint Derangements

The aim of this study was to evaluate the effectiveness of intra-articular injection of liquid platelet-rich fibrin (I-PRF) versus hyaluronic acid (HA) following arthrocentesis in patients suffering from temporomandibular joint (TMJ) pain and dysfunction. A total of 69 patients with internal TMJ derangement were enrolled in this retrospective, matched cohort study. A total of 47 included patients (67 joints) were divided into 3 groups as follows: 16 participants in the arthrocentesis-only group; 14 patients in the arthrocentesis plus HA injection group (A+HA); and 17 participants in the arthrocentesis plus I-PRF injection group (A+I-PRF). The 2 outcome variables were TMJ pain and maximal mouth opening (MMO) which were evaluated up to 12 months postoperatively. The data were analyzed using the Shapiro-Wilk test, Kruskal-Wallis test, Mann-Whitney U test, Wilcoxon sign test, Fisher exact test, and the χ test. Statistically significant decreases in pain scores and increases in MMO values were observed in all 3 groups during the 12 months of follow-up. The significant decrease in pain values was shown in the A+I-PRF group as compared with the A+HA group at 9 months postoperatively. MMO values in the A+I-PRF group were significantly higher than in the A+HA group at 9 and 12 months postoperatively. All conventional treatment procedures can provide pain reduction and improvement to MMO. However, intraarticular injections of I-PRF in combination with arthrocentesis showed superior performance in terms of the gradual improvement in pain alleviation and range of mouth opening.

Improved growth factor delivery and cellular activity using concentrated platelet-rich fibrin (C-PRF) when compared with traditional injectable (i-PRF) protocols

OBJECTIVES

Several studies have recently demonstrated that only marginal improvements in platelet and leukocyte concentrations are achieved following standard injectable platelet-rich fibrin (i-PRF) protocols. Due to these previous findings, a novel harvesting technique was recently developed to collect higher concentrations of platelets/leukocytes specifically from the buffy coat layer (C-PRF) following faster centrifugation protocols. The aim of this study was to investigate the regenerative properties and effects on growth factor release and cellular activity of PRF collected through this novel harvesting technique compared to standard i-PRF protocols.

MATERIALS AND METHODS

The upper 1-ml layer collected through standard i-PRF protocols at low centrifugation speeds was compared with 1 mL of C-PRF collected from the buffy coat layer following high centrifugation protocols (3000×g for 8 min on a horizontal centrifuge) to specifically concentrate cells within the platelet/leukocyte-rich buffy coat layer. Thereafter, the expression of seven different growth factors, including PDGF-AA, PDGF-AB, PDGF-BB, TGF-β1, VEGF, IGF-1, and EGF, was characterized for up to 10 days. Then, gingival fibroblast biocompatibility was investigated at 24 h (live/dead assay); migration was investigated at 24 h; proliferation was investigated at 1, 3, and 5 days; and the expression of PDGF and TGF-β was investigated at 3 days. Collagen 1 immunostaining was also quantified at 14 days.

RESULTS

At all investigated time periods, a significant increase in growth factor release was observed in C-PRF. In particular, the release of PDGF-AA, TGF-β1, and EGF exhibited the highest increases when compared with that in i-PRF. While both i-PRF and C-PRF exhibited high biocompatibility and induced significantly higher fibroblast migration and proliferation when compared with that of the control tissue culture plastic group, C-PRF showed the greatest potential for cell migration and proliferation. Furthermore, C-PRF induced significantly higher mRNA levels of TGF-β and PDGF levels at 3 days and greater collagen 1 staining when compared with induced by i-PRF.

CONCLUSIONS

In the present study, it was found that C-PRF collected specifically from the buffy coat layer following higher centrifugation protocols exhibited an up to a threefold increase in growth factor release when compared with that exhibited by standard i-PRF. This significantly promoted higher gingival fibroblast migration, proliferation, gene expression, and collagen I synthesis.

CLINICAL RELEVANCE

The findings of the present study demonstrate that a more potent formulation of liquid platelet concentrate than that obtained from the upper plasma layer following a short and slow centrifugation protocol (i-PRF protocol) can be obtained for clinical use by specifically harvesting cells in the platelet- and leukocyte-rich buffy coat layer following an 8-min 3000×g centrifugation protocol (C-PRF protocol).

Therapeutic Potential of Dental Pulp Stem Cells and Leukocyte- and Platelet-Rich Fibrin for Osteoarthritis

Osteoarthritis (OA) is a degenerative and inflammatory joint disorder with cartilage loss. Dental pulp stem cells (DPSCs) can undergo chondrogenic differentiation and secrete growth factors associated with tissue repair and immunomodulation. Leukocyte- and platelet-rich fibrin (L-PRF) emerges in regenerative medicine because of its growth factor content and fibrin matrix. This study evaluates the therapeutic application of DPSCs and L-PRF in OA via immunomodulation and cartilage regeneration. Chondrogenic differentiation of DPSCs, with or without L-PRF exudate (ex) and conditioned medium (CM), and of bone marrow-mesenchymal stem cells was compared. These cells showed differential chondrogenesis. L-PRF was unable to increase cartilage-associated components. Immature murine articular chondrocytes (iMACs) were cultured with L-PRF ex, L-PRF CM, or DPSC CM. L-PRF CM had pro-survival and proliferative effects on unstimulated and cytokine-stimulated iMACs. L-PRF CM stimulated the release of IL-6 and PGE2, and increased MMP-13, TIMP-1 and IL-6 mRNA levels in cytokine-stimulated iMACs. DPSC CM increased the survival and proliferation of unstimulated iMACs. In cytokine-stimulated iMACs, DPSC CM increased TIMP-1 gene expression, whereas it inhibited nitrite release in 3D culture. We showed promising effects of DPSCs in an in vitro OA model, as they undergo chondrogenesis in vitro, stimulate the survival of chondrocytes and have immunomodulatory effects.

Combination of an allogenic and a xenogenic bone substitute material with injectable platelet-rich fibrin - A comparative in vitro study

The aim of the in vitro study was a comparison of an allogenic (ABSM) and a xenogenic bone substitute material (XBSM) with and without injectable platelet-rich fibrin (ABSM-i-PRF & XBSM-i-PRF) on cell characteristics of human osteoblasts (HOB). Here, ABSM and XBSM (+ i-PRF = test; - i-PRF = control) were incubated with HOB for 3, 7 and 10 days. HOB viability, migration, proliferation and differentiation (RT-PCR on alkaline phosphatase (AP), bone morphogenetic protein 2 (BMP-2) and osteonectin (OCN)) were measured and compared between groups. At day 3, an increased viability, migration and proliferation was seen for ABSM-i-PRF. For viability and proliferation (days 7 and 10) and for migration (day 10), ABSM-i-PRF/XBSM-i-PRF showed higher values compared to ABSM/XBSM with maximum values for ABSM-i-PRF and minimum values for XBSM. At days 3 and 7, the highest expression of AP was detected in ABSM-i-PRF/XBSM-i-PRF when compared to ABSM/XBSM, whereas at day 10, AP expression levels were elevated in ABSM-i-PRF/ABSM. The highest BMP-2 expression was seen in ABSM-i-PRF whereas OCN expression showed higher levels in ABSM-i-PRF/XBSM-i-PRF at days 3 and 7 with lowest expression for ABSM. Later on, elevated OC levels were detected for ABSM-i-PRF only. In conclusion, i-PRF in combination with ABSM enhances HOB activity when compared to XBSM-i-PRF or untreated BSM in vitro. Therefore, addition of i-PRF to ABSM and - to a lower extent - to XBSM may influence osteoblast activity in vivo.

A novel method for harvesting concentrated platelet-rich fibrin (C-PRF) with a 10-fold increase in platelet and leukocyte yields

BACKGROUND AND OBJECTIVES

Liquid platelet rich fibrin (PRF; often referred to as injectable PRF) has been utilized as an injectable formulation of PRF that is capable of stimulating tissue regeneration. Our research group recently found that following standard L-PRF protocols (2700 RPM for 12 min), a massive increase in platelets and leukocytes was observed directly within the buffy-coat layer directly above the red blood cell layer. The purpose of this study was to develop a novel harvesting technique to isolate liquid PRF directly from this buffy coat layer and to compare this technique to standard i-PRF.

MATERIALS AND METHODS

Standard high g-force L-PRF and low g-force i-PRF protocols were utilized to separate blood layers. Above the red blood corpuscle layer, sequential 100-μL layers of plasma were harvested (12 layers total; i.e., 1.2 mL, which represents the total i-PRF volume), and 3 layers (3 × 100 μL) were harvested from the red blood cell layer to quantify blood cells. Each layer was then sent for complete blood count (CBC) analysis, and the cell numbers were quantified including red blood cells, leukocytes, neutrophils, lymphocytes, monocytes, and platelets. The liquid PRF that was directly collected from the buffy-coat layer following L-PRF protocols was referred to as concentrated PRF (C-PRF).

RESULTS

The i-PRF protocol typically yielded a 2- to 3-fold increase in platelets and a l.5-fold increase in leukocyte concentration from the 1- to 1.2-mL plasma layer compared to baseline concentrations in whole blood. While almost no cells were found in the first 4-mL layer of L-PRF, a massive accumulation of platelets and leukocytes was found directly within the buffy coat layer demonstrating extremely high concentrations of cells in this 0.3-0.5-mL layer (~ 20-fold increases). We therefore proposed harvesting this 0.3- to 0.5-mL layer directly above the red blood cell corpuscle layer as liquid C-PRF. In general, i-PRF was able to increase platelet numbers by ~ 250%, whereas a 1200-1700% increase in platelet numbers could easily be achieved by harvesting this 0.3-0.5 mL of C-PRF (total platelet concentrations of > 2000-3000 × 10⁹ cells/L).

CONCLUSION

While conventional i-PRF protocols increase platelet yield by 2-3-fold and leukocyte yield by 50%, we convincingly demonstrated the ability to concentrate platelets and leukocytes over 10-fold by harvesting the 0.3-0.5 mL of C-PRF within the buffy coat following L-PRF protocols.

CLINICAL RELEVANCE

Previous studies have demonstrated only a slight increase in platelet and leukocyte concentrations in i-PRF. The present study described a novel harvesting technique with over a 10-fold increase in platelets and leukocytes that can be further utilized for tissue regeneration.

[Research progress on platelet-rich fibrin derivatives]

Platelet-rich plasma and platelet-rich fibrin (PRF) are widely used in the field of stomatology. Advance-ments in preparation techniques and basic research have enabled the use of PRF derivatives in oral clinical applications. The evolution, preparation techniques, biological properties, and medical research progress of PRF derivatives are reviewed in this paper.

New Frontiers in Skin Rejuvenation, Including Stem Cells and Autologous Therapies

One of the greatest challenges in the progression of aesthetic medicine lies in providing treatments with long-term results that are also minimally invasive and safe. Keeping up with this demand are developments in autologous therapies such as adipose-derived stem cells, stromal vascular fraction, microfat, nanofat, and platelet therapies, which are being shown to deliver satisfactory results. Innovations in more traditional cosmetic therapies, such as botulinum toxin, fillers, and thread lifts, are even more at the forefront of the advancement in aesthetics. Combining autologous therapies with traditional noninvasive methods can ultimately provide patients with more effective rejuvenation options.

Anti-inflammation effects of injectable platelet-rich fibrin via macrophages and dendritic cells

Immune response to implantation materials plays a critical role during early local inflammation and biomaterial-induced regeneration or restoration. A novel platelet concentrate termed i-PRF (injectable platelet-rich fibrin) has recently been developed without any additives by low centrifugation speeds. To date, scientists have investigated the capability of releasing growth factors to improve regeneration but have ignored whether i-PRF can inhibit the inflammatory effect around the wound. The present study investigated the anti-inflammation effects of i-PRF on immune response-related cells, especially macrophages and dendric cells. We found that i-PRF reduced pro-inflammatory M1 phenotype of macrophages and activated dendritic cells around muscle defect that was injected with bacterial suspension. Moreover, in vitro experiments showed similar results. i-PRF deleted inflammatory response caused by lipopolysaccharide to some extent. We determined that TLR4, an activator of inflammatory stimulation and p-p65, a key factor belongs to classical inflammatory related NF-κB signal pathway, can be inhibited by use of i-PRF. Results indicate the potential anti-inflammatory role of i-PRF during regeneration and restoration.

Platelet-Rich Fibrin and its Emerging Therapeutic Benefits for Musculoskeletal Injury Treatment

New therapies that accelerate musculoskeletal tissue recovery are highly desirable. Platelet-rich fibrin (PRF) is a leukocyte- and platelet-rich fibrin biomaterial that acts as a binding site for both platelets and growth factors. Through increasing the local concentration of growth factors at specific tissues, PRF promotes tissue regeneration. PRF has been frequently used in combination with bone graft materials to reduce healing times and promote bone regeneration during maxillofacial surgery. However, its benefits during muscle repair and recovery are less well-documented. Here, we perform a narrative review on PRF therapies and muscle injuries to ascertain its beneficial effects. We reviewed the factors that contribute to the biological activity of PRF and the published pre-clinical and clinical evidence to support its emerging use in musculoskeletal therapy. We include in vitro studies, in vivo animal studies and clinical articles highlighting both the success and failures of PRF treatment. PRF can promote the healing process when used in a range of orthopaedic and sports-related injuries. These include cartilage repair, rotator cuff surgery and anterior cruciate ligament surgery. However, conflicting data for these benefits have been reported, most likely due to inconsistencies in both PRF preparation protocols and dosing regimens. Despite this, the literature generally supports the use of PRF as a beneficial adjuvant for a range of chronic muscle, tendon, bone or other soft tissue injuries. Further clinical trials to confirm these benefits require consistency in PRF preparation and the classification of a successful clinical outcome to fully harness its potential.

Platelet-Rich Fibrin Scaffolds for Cartilage and Tendon Regenerative Medicine: From Bench to Bedside

Nowadays, research in Tissue Engineering and Regenerative Medicine is focusing on the identification of instructive scaffolds to address the requirements of both clinicians and patients to achieve prompt and adequate healing in case of injury. Among biomaterials, hemocomponents, and in particular Platelet-rich Fibrin matrices, have aroused widespread interest, acting as delivery platforms for growth factors, cytokines and immune/stem-like cells for immunomodulation; their autologous origin and ready availability are also noteworthy aspects, as safety- and cost-related factors and practical aspects make it possible to shorten surgical interventions. In fact, several authors have focused on the use of Platelet-rich Fibrin in cartilage and tendon tissue engineering, reporting an increasing number of in vitro, pre-clinical and clinical studies. This narrative review attempts to compare the relevant advances in the field, with particular reference being made to the regenerative role of platelet-derived growth factors, as well as the main pre-clinical and clinical research on Platelet-rich Fibrin in chondrogenesis and tenogenesis, thereby providing a basis for critical revision of the topic.

Influence of Fractionation Methods on Physical and Biological Properties of Injectable Platelet-Rich Fibrin: An Exploratory Study

Injectable platelet-rich fibrin (i-PRF) has been used as an autografting material to enhance bone regeneration through intrinsic growth factors. However, fractionation protocols used to prepare i-PRF can be varied and the effects of different fractionation protocols are not known. In this study, we investigated the influence of different fractions of i-PRF on the physical and biological properties derived from variations in i-PRF fractionation preparation. The i-PRF samples, obtained from the blood samples of 10 donors, were used to harvest i-PRF and were fractioned into two types. The yellow i-PRF fractionation was harvested from the upper yellow zone, while the red i-PRF fractionation was collected from both the yellow and red zone of the buffy coat. The viscoelastic property measurements, including the clot formation time, α-angle, and maximum clot firmness, were performed by rotational thromboelastometry. The fibrin network was examined using a scanning electron microscope. Furthermore, the concentration of growth factors released, including VEGF, TGF-β1, and PDGF, were quantified using ELISA. A paired t-test with a 95% confidence interval was used. All three viscoelastic properties were statistically significantly higher in the yellow i-PRF compared to the red i-PRF. The scanning electron microscope reviewed more cellular components in the red i-PRF compared to the yellow i-PRF. In addition, the fibrin network of the yellow i-PRF showed a higher density than that in the red i-PRF. There was no statistically significant difference between the concentration of VEGF and TGF-β1. However, at Day 7 and Day 14 PDGF concentrations were statistically significantly higher in the red i-PRF compared to the yellow group. In conclusion, these results showed that the red i-PRF provided better biological properties through the release of growth factors. On the other hand, the yellow i-PRF had greater viscoelastic physical properties. Further investigations into the appropriate i-PRF fractionation for certain surgical procedures are therefore necessary to clarify the suitability for each fraction for different types of regenerative therapy.

Platelet-Rich Plasma and Cartilage Repair

PURPOSE OF REVIEW

To assess the utilization and efficacy of platelet-rich plasma (PRP), for the treatment of articular cartilage injury, most commonly characterized by progressive pain and loss of joint function in the setting of osteoarthritis (OA).

RECENT FINDINGS

PRP modulates the inflammatory and catabolic environment through a locally applied concentrate of platelets, leukocytes, and growth factors. Clinically, PRP has been shown to be possibly a viable treatment adjuvant for a variety of inflammatory and degenerative conditions. Recent efforts have focused on optimizing delivery methods that enable platelets to slowly degranulate their biological constituents, which may promote healing and improve OA symptoms for a longer duration. There are various factors that affect the progression of OA within joints, including inhibition of inflammatory cytokines and altering the level of enzymatic expression. PRP therapy aims to mediate inflammatory and catabolic factors in a degenerative environment through the secretion of anti-inflammatory factors and chemotaxic effects. There are a growing number of studies that have demonstrated the clinical benefit of PRP for non-operative management of OA. Additional randomized controlled trials with long-term follow-up are needed in order to validate PRP's therapeutic efficacy in this setting. Additionally, continued basic research along with well-designed pre-clinical studies and reporting standards are necessary in order to clarify the effectiveness of PRP for cartilage repair and regeneration for future clinical applications.

Telomere length and genetic variations affecting telomere length as biomarkers for facial regeneration with platelet-rich fibrin based on the low-speed centrifugation concept

BACKGROUND

Platelet-Rich Fibrin (PRF), a fibrin matrix produced by single blood centrifugation that contains leukocytes, platelets, and growth factors, is increasingly being utilized for facial regeneration purposes. However, our understanding of the involved pathophysiological mechanisms affecting regeneration is limited and current protocols require better optimization. Biomarkers that are related to skin aging such as telomere length (TL) have been proposed as a mean to analyze patients' stratification.

OBJECTIVE

Our aim is to study whether the outcomes of a facial regeneration protocol performed with PRF are related to TL and genetic variations affecting TL. This can aid in the standardization of a surgical aesthetic protocol.

PATIENTS AND METHODS

In all, 41 patients treated with PRF produced with the low-speed centrifugation concept were included in this observational study. The correlation between TL and genetic variations were assessed versus treatment outcomes, namely the number of sessions and aesthetic results utilizing the FACE-Q skin satisfaction questionnaire.

RESULTS

In all, 39 of the 41 patients completed the treatment. TL correlated with the initial responses to FACE-Q (ρ = .33, P = .05). Genetic variations affecting TL was related to the change of FACE-Q (ρ = .35, P = .034) as well as to the number of treatment sessions (ρ = .38, P = .019).

CONCLUSIONS

Telomere length (TL) was related to patient perceived facial skin appearance. In addition, genetic variations affecting TL were related to the final outcomes (number of sessions and improvements of FACE-Q results) and may be a useful biomarker for future regenerative procedures performed with PRF for facial regeneration.

A Novel and Convenient Method for the Preparation and Activation of PRP without Any Additives: Temperature Controlled PRP

Platelet rich plasma (PRP) is a concentrate of autologous platelets which contain enrichment growth factors (GFs). However, the addition of exogenous anticoagulant and procoagulant may result in clinical side effects and raise the price of PRP. Herein, we report a novel method named temperature controlled PRP (t-PRP), in which exogenous additives are dispensable in the preparation and activation process. Human blood samples were processed by a two-step centrifugation process under hypothermic conditions (4°C) to obtain t-PRP and rewarming up to 37°C to activate t-PRP. Contemporary PRP (c-PRP) was processed as the control. t-PRP showed a physiological pH value between 7.46 and 7.48 and up to 6.58 ± 0.45-fold significantly higher platelet concentration than that of whole blood compared with c-PRP (4.06-fold) in the preparation process. Meanwhile, t-PRP also maintained a stable GF level between plasma and PRP. After activation, t-PRP demonstrated natural fiber scaffolding, which trapped more platelet and GFs, and exhibited a slow release and degradation rate of GFs. In addition, t-PRP exhibited the function of promoting wound healing. t-PRP is a novel and convenient method for the preparation and activation of PRP without any additives. Compared to c-PRP, t-PRP reflects more physiologic characteristics while maintaining high quality.