Vascularization after treatment of gingival recession defects with platelet-rich fibrin or connective tissue graft

Ultrasonographic analysis of palatal donor site healing accelerated with platelet-rich fibrin following subepithelial connective tissue harvesting

OBJECTIVE

Platelet-rich fibrin (PRF) contains a variety of growth factors and bioactive molecules that play crucial roles in wound healing and angiogenesis. We aimed to evaluate the effects of PRF on tissue thickness and vascularization of the palatal donor site by ultrasound (USG) following subepithelial connective tissue harvesting.

METHODOLOGY

A subepithelial connective tissue graft was harvested from the palatal region with a single incision for root coverage in 20 systemically healthy patients. In the test group (n = 10), the PRF membrane was placed at the donor site, whereas no material was applied in the control group (n=10). Palatal tissue thickness (PTT) and pulsatility index (PI) were evaluated by USG at baseline and on the 3rd, 7th, 14th, 30th, and 90th days after surgery. The early healing index (EHI) was used to evaluate donor site healing for 30 days.

RESULTS

PTT was significantly higher in the PRF group on the 3rd and 14th days after surgery when compared to the controls. In the PRF-treated group, PI levels were significantly higher than in the controls, especially on the 14th day. PTT increased significantly 90 days after surgery compared to the test group baseline, but controls showed a significant decrease. The PRF group showed statistically significant improvements in EHI scores compared to controls on days 3, 7, and 14. This study found a negative correlation between PI values and EHI scores on postoperative days three and seven in the test group.

CONCLUSION

USG is a non-invasive, objective method to radiographically evaluate the regenerative effects of PRF on palatal wound healing after soft tissue harvesting. To overcome graft inadequacy in reharvesting procedures, PRF application may enhance clinical success and reduce possible complications by increasing tissue thickness and revascularization in the donor area.

Pleiotropic effect of intramucosal injection of FTY720 on angiogenesis and tissue healing after free gingival graft surgery: a comparative experimental study in rabbits

OBJECTIVES

Free gingival graft surgery is the gold standard for increasing the size of keratinized tissue. Blood supply in the recipient site is critical for healing. Therefore, in this study, the effect of FTY720 on angiogenesis, healing, and scar tissue presence following free gingival graft surgery is investigated.

MATERIALS AND METHODS

Surgeries were performed on 10 New Zealand white rabbits. Rabbits were randomly assigned to two groups. In the experimental group, immediately after surgery, 2 and 4 days later, FTY-720 was injected into the tissue surrounding the recipient site. In the control group, the same frequency of placebo vehicle was injected. After 30 days, tissue samples were assessed histologically and histomorphometrically.

RESULTS

The blood vessel count (P < 0.000) and rete ridge formation (P < 0.05) in the experimental group were significantly higher, while the epithelial thickness was lower in this group (P < 0.000). There was no significant difference in the percentage of regions occupied by collagen fibres between the groups (P = 0.987). Furthermore, a significant and negative relationship between epithelial thickness and blood vessel count was shown (Pearson correlation coefficient =  - 0.917).

CONCLUSIONS

The findings indicate that the angiogenic effects of FTY-720 in the recipient site of free gingival graft can be employed to promote tissue healing and reduce scar tissue presence.

CLINICAL RELEVANCE

A significant decrease in epithelial thickness and increase in angiogenesis as well as rete ridge formation score in the FTY-720 group were shown, which can be translated into improved tissue healing and less presence of scar tissue.

Root coverage with platelet-rich fibrin or connective tissue graft: a split-mouth randomized trial

This study aimed to compare the use of connective tissue grafts (CTG) and platelet-rich fibrin (PRF) associated with the tunnel technique (TT) for the treatment of multiple gingival recessions (GR). Fourteen patients with multiple bilateral GR [type 1 recession (RT 1)] in the maxillary incisors, canines, and/or premolars were included. The TT was performed on both sides (split-mouth model); CTG (36 GR) was used on one side, and on the other, PRF (36 GR) was used. Clinical parameters, including recession depth (RD), probing depth, clinical attachment level (CAL), and keratinized gingiva thickness/width (GT/KTW), were obtained at baseline and after 1, 3, 6, and 16 months. Lower RD (0.81 ± 0.68 vs. 1.23 ± 0.71 mm) and CAL (2.54 ± 0.63 vs. 2.73 ± 0.82 mm) were observed for CTG compared to PRF after 16 months. Higher GT was obtained for CTG compared to PRF after 3 (1.81 ± 0.56 vs 1.43 ± 0.47 mm) and 6 months (1.67 ± 0.61 vs. 1.38 ± 0.55 mm, p < 0.05). The recession coverage (RC) was higher for CTG (55.42% ± 37.14) in comparison to PRF (29.53% ± 34.08) after 16 months (p < 0.05). Similarly, CTG presented a more complete coverage of the recession (15; 41.66%) than PRF (9; 24.32%). There were no significant differences between the groups in terms of surgery time, postoperative pain, or healing patterns. Greater esthetic satisfaction was obtained with CTG. It was concluded that CTG combined with TT showed clinical and esthetic results superior to those of PRF in multiple GR treatments.

Platelet-rich fibrin vs. buccal advancement flap for closure of oroantral communications: a prospective clinical study

OBJECTIVES

The primary aim was to evaluate the success of the defect closure (tight or open) of oroantral communications (OAC) after treatment with platelet-rich fibrin (PRF) clots or a buccal advancement flap (BAF). Secondary outcome measurements were the evaluation of the wound healing, the displacement of the mucogingival border (MGB), and the pain level.

MATERIAL AND METHODS

Fifty eligible patients with an OAC defect larger than 3 mm were randomly assigned to either PRF (test group, n = 25) or BAF (control group, n = 25) for defect closure. In a prospective follow-up program of 21 days, the defect closure healing process, the wound healing course using Landry's wound healing index (score: 0-5), the displacement of the MGB, and the postoperative pain score were evaluated.

RESULTS

Five patients in each group were lost to follow-up resulting in 40 patients (20 in each group) for continuous evaluation. On postoperative day 21 (study endpoint), no difference regarding success rate (defined as closure of OAC) was noticed between the test (90%; 18/20) and control group (90%; 18/20). A univariate analysis showed significant differences for age and defect size/height for the use of PRF between successful-tight and open-failed defect healing. At the final evaluation, a significantly (p = 0.005) better wound healing score, a lower displacement of the MGB as well as lower pain-score were seen for the use of PRF.

CONCLUSIONS

Based on the findings of the current study, the use of platelet-rich fibrin represents a reliable and successful method for closure of oroantral communications. The use of PRF clots for defect filling is associated with lowered pain levels and less displacement of the mucogingival border.

CLINICAL RELEVANCE

The defect size should be taken into account when choosing the number and size of PRF plugs.

Gingival phenotype changes after different periodontal plastic surgical techniques: a single-masked randomized controlled clinical trial

ABSTRACT: OBJECTIVES: Aim of this clinical study was to evaluate the effects on gingival thickness of three surgical techniques for root coverage: the coronally advanced flap (CAF) alone, with a sub-epithelial connective tissue graft (SCTG) or with leukocyte- and platelet-rich fibrin (L-PRF) membranes.

METHODS

Sixty patients with RT1 single maxillary gingival recession were treated with CAF + L-PRF (20 patients), CAF + SCTG (20 patients) or CAF alone (20 patients). At baseline and 6-month after treatment, gingival thickness (GT), keratinized tissue width (KT), gingival recession (GR), clinical attachment level (CAL), probing depth (PD), PROMs, and the aesthetic outcome were recorded.

RESULTS

CAF + SCTG and CAF + L-PRF groups showed a significantly greater mean GT increase than CAF alone (0.31 ± 0.10 mm) with no significant differences between CAF + SCTG (0.99 ± 0.02 mm) and CAF + L-PRF (0.92 ± 0.52 mm) groups (p = 0.55). CAF + SCTG was associated with a significantly greater KT gain (3.85 ± 1.04 mm), while in CAF + L-PRF (2.03 ± 0.53 mm) and CAF (1.50 ± 0.69 mm) groups, KT was not significantly increased. Both GR and CAL showed a significant within groups' improvement, without among-groups differences. No significant among-groups difference for the aesthetic outcome but greater discomfort and pain-killer consumption in CAF + SCTG group was detected.

CONCLUSION

All investigated surgical techniques produced significant GR reduction and CAL gain. GT was similarly augmented by CAF + L-PRF and CAF + SCTG techniques; however, the CAF + SCTG technique produced a more predictable KT and GT increase.

CLINICAL RELEVANCE

The results of our study suggest that the CAF + SCTG technique represents the most predictable method for the clinician to improve the gingival phenotype, an important factor for long term gingival margin stability.

Fibrin immobilization vestibular extension (FIVE): A case series

AIMS

The objective of the present case series is to report on the rationale, surgical technique and outcome of a protocol for peri-implant mucosal phenotype modification therapy, referred to as "fibrin immobilization vestibular extension (FIVE)".

MATERIAL AND METHODS

The protocol utilized entailed apical positioning and stabilization of peri-implant flap with modular screws. The screws were also used for the immobilization of solid matrix platelet-rich fibrin to fill the gap created between apically positioned flap and the crestal margin of the flap.

RESULTS

A total of 30 patients (12 male, 18 females) with 93 implants were treated with FIVE protocol for various indications, including for vestibular extension following alveolar ridge augmentation (N = 6), preprosthetic (N = 9), postprosthetic (N = 2), and peri-implantitis (N = 13). The keratinized mucosal width preoperatively was 1.67 mm with 95% confidence interval [CI] (1.46, 1.88). Immediately following FIVE surgery, the vestibule was extended to 9.10 with 95% CI (8.44, 9.76). At 3 months, 4.9 mm (95% CI: 4.5-5.2 mm) of peri-implant keratinized mucosal width was present. The keratinized mucosal width remained relatively stable thereafter and was 4.0 mm (95% CI: 3.5-4.5 mm) at 3 years post-FIVE surgery. When overall group means across all time points were analyzed, maxilla had mean of 6.1 mm (95% CI: 5.8-6.5) versus mandible exhibited mean of 5.1 mm (95% CI: 4.6-5.6 mm). The mean of maxilla was significantly higher than that of the mandible (p < 0.0001) across all time points. Treatment of peri-implantitis with FIVE lead to significant pocket reduction and wide band of keratinized mucosa. Seven of 38 implants in 3 of 13 peri-implantitis patients were removed due to advanced peri-implantitis.

DISCUSSION

The present case series provides proof-of-principle data for efficacy of FIVE for peri-implant phenotype modification therapy that generated attached keratinized mucosa in a variety of applications. This protocol provides an alternative to procedures involving harvesting of autogenous mucosal graft.

Biological Basis of Periodontal Regeneration

The ultimate goal of periodontal therapy is homeostatic regeneration of lost attachment of alveolar bone and gingival connective tissue to the exposed root surfaces with a fully functional and healthy periodontal ligament that is covered with a healthy epithelium. This goal needs a complete understanding of the biological mechanisms inherent to healing and inflammatory processes.

Patient-centered comparative outcome analysis of platelet-rich fibrin-reinforced vestibular incision subperiosteal tunnel access technique and Zucchelli's technique

Background:

Multiple gingival recession (MGR) coverage, especially in esthetic area, demands a high patient satisfaction. Coronally advanced flap modifications, namely Zucchelli's technique (ZT) and vestibular incision subperiosteal tunnel access (VISTA), are techniques, recommended in the correction of MGR.

Aim:

The purpose was to comparatively analyze the ZT and VISTA technique reinforced with the platelet-rich fibrin membrane in the management of MGR.

Materials and Methods:

This split-mouth, randomized study comprised 16 consenting, systemically healthy participants. The bilateral Miller's multiple class I and II lesions were managed with ZT and VISTA technique and had a follow-up period of 18 months. Gingival thickness (GT), mean percentage of root coverage, and patient-centered outcome scales, including patient comfort score, patient esthetic score, and hypersensitivity score, were the primary outcome measures. Further clinical parameters assessed were gingival index, probing depth, clinical attachment level, and width of keratinized gingiva.

Statistical Analysis and Results:

Paired t-test and unpaired t-test were used for intragroup comparison and intergroup analysis, respectively. While both the techniques exhibited high root coverage percentage (VISTA: 93.95% and ZT: 96.84%), statistically significant difference was noted with patient esthetic score and surgical mortality score in VISTA.

Conclusion:

Both ZT and VISTA were effective in terms of root coverage and GT augmentation in MGR management. From the patient's perspective, they preferred VISTA technique over ZT, stating its minimal postoperative morbidity and improved esthetic outcome. Hence, within the limitations of this study, the VISTA technique was found to be a superior alternative compared to that of ZT in MGR management.

Treatment of Miller I Mandibular Gingival Recessions Using PRF vs. Connective Graft

Gingival recession (GR) can cause aesthetic and functional problems. Using connective tissue graft (CTG) and coronally advanced flap (CAF) is considered the technique of choice for treating GR. Considering the morbidity resulting from taking CTG, different alternative biomaterials have been described, including plasma-rich fibrin (PRF) membrane. Studies in lower teeth are few because of the complexity of the factors that can influence obtaining less predictable outcomes. Objective. To compare between CAF + PRF and CAF + CTG in the treatment of lower teeth Miller I gingival recession. Methodology. Split-mouth included 26 isolated GR (13 in each side of the mouth). The left side was treated with CAF + PRF and the right side with CAF + CTG. Clinical variables, probing depth (PD), GR, keratinized tissue (KT), vestibular soft tissue thickness (VSTT), and teeth sensitivity (TS), were assessed at the baseline. GR, KT, VSTT, extraoral inflammation (EI), and patient discomfort (PaD) were assessed at 45 days. Results. Statistically greater VSTT at 45 days was obtained using CAF + CTG (p < 0.05). Less EI and PaD were obtained using CAF + PRF (p < 0.05). No change was observed in GR, KT, and TS values in the intergroup or intragroup comparisons. Conclusion. Even with the limitations of this study, using PRF and CTG in lower teeth demonstrated an improvement in terms of root coverage, although it was without a total percentage of coverage. Regarding the VSTT, better results were obtained using the CTG + CAF, suggesting eventually long-term stable clinical results. We suggest a combined technique for future investigations.

Critical features of periodontal flaps with regard to blood clot stability: A review

BACKGROUND

Wound healing is a multifactorial procedure involving different cell types and biological mediators. The principles of wound healing are also applicable to periodontal tissues. The formation and stability of blood clots play a vital role in successful healing of wounds in periodontal tissues. The aim of the present review was to highlight the vital factors of periodontal flaps associated with blood clot stability.

HIGHLIGHT

The data on periodontal regeneration and wound healing have evolved greatly in light of several factors, including space for blood clots and blood clot stabilization. In periodontal osseous defects, the stability of blood clots seems critical to wound healing. If mechanical forces can be managed by wound stabilization, the gingival flap-tooth root interface may show connective tissue repair. However, compromised adhesion is susceptible to mechanical forces and can cause wound breakage and epithelialization.

CONCLUSION

The presence of a thick blood clot may hinder the plasmatic circulation between the recipient bed and graft during the initial stage of healing, which is critical in cases of mucogingival surgery. Root conditioning can also determine the healing consequence by enhancing blood clot adhesion.

Platelet-Rich Fibrin in Single and Multiple Coronally Advanced Flap for Type 1 Recession: An Updated Systematic Review and Meta-Analysis

Background and Objectives: The aim of the present systematic review and meta-analysis was to investigate the efficacy of leukocyte–platelet-rich fibrin (L-PRF) in addition to coronally advanced flap (CAF) for the treatment of both single and multiple gingival recessions (GRs) compared to the CAF alone and to the adjunct of connective tissue graft (CTG). Root coverage outcomes using platelet concentrates have gained increased interest. In particular, it has been suggested that adding L-PRF to CAF may provide further benefits in the treatment of GRs. Materials and Methods: An electronic and manual literature search was conducted to identify randomized controlled trials (RTCs) investigating root coverage outcomes with CAF + L-PRF. The outcomes of interest included mean root coverage (mRC), recession reduction, keratinized tissue width (KTW) gain, gingival thickness (GT) gain, and patient-reported outcome measures (PROms) such as pain perception and discomfort. Results: A total of 275 patients and 611 surgical sites were analyzed. L-PRF in adjunct to single CAF seems to show statistically significant results regarding clinical attachment level (CAL) with a weighted means (WM) 0.43 95% CI (−0.04, 0.91), p < 0.0001, GT (WM 0.17 95% CI (−0.02, 0.36), p < 0.0001, and mRC (WM 13.95 95% CI (−1.99, 29.88) p < 0.0001, compared to single CAF alone. Interesting results were obtained from the adjunct of PRF to multiple CAF with respect to multiple CAF alone with an increase in the mRC WM 0.07 95% CI (−30.22, 30.35), p = 0.0001, and PPD change WM 0.26 95% CI (−0.06, 0.58), p < 00001. On the other hand, no statistically significant data were obtained when L-PRF was added to single or multiple CAF combined with CTG according to the included outcomes such as mRC (p = 0.03 overall). Conclusions: L-PRF is a valid alternative to CAF alone. L-PRF compared to CTG in single and multiple CAF showed statistically significant results regarding pain perception and discomfort PROms (p < 0.0001). However, CTG remains the gold standard for treating gingival recession.

Gingival Thickness and Outcome of Periodontal Plastic Surgery Procedures: A Meta-regression Analysis

OBJECTIVE

To evaluate the impact of soft tissue thickness (STT) on root coverage achieved with different periodontal plastic surgery procedures.

BACKGROUND

Gingival recession has been managed successfully through various surgical approaches, with great variability in outcomes. Anatomic characteristics of the recipient site and selected technique account in part for this variability. Gingival flap thickness is one of the most critical site-related characteristics.

METHODS

An electronic search was conducted on the major databases (PubMed, Embase, Web of Science). Human prospective studies with at least 6 mo of follow-up and with a numeric baseline measurement for gingival thickness were eligible. Only studies including nonsmoking patients were considered. Variables included surgical approach, participant characteristics, local anatomic factors, and follow-up time. Primary outcome was mean percentage root coverage (%RC) achieved, and complete root coverage was a secondary outcome.

RESULTS

A total of 42 studies were included (35 randomized controlled trials, 5 case series, 1 prospective cohort study, and 1 controlled clinical trial). Across studies, the pooled %RC was 81.9% (95% CI, 79.1% to 84.7%). The %RC was not significantly associated (P = 0.267) with baseline soft tissue thickness; however there was a significant (P = 0.031) inverse relationship between STT and %RC after 12-mo follow-up. Subgroup analysis showed that for no graft, there was a significant (P = 0.025) positive relationship between STT and %RC with the exclusion of the single outlier study based on STT.

CONCLUSIONS

STT plays a limited role in predicting root coverage across all approaches; when flaps are performed with no graft, the effect of STT is most critical. The length of time following surgery appears to influence outcomes, with 12-mo follow-up offering greater insight.

KNOWLEDGE TRANSFER STATEMENT

The results of this study can suggest to clinicians which periodontal plastic surgery technique to employ when treating challenging cases. In particular, it can be helpful when selecting the treatment approach to treat thin phenotype sites. This study could help clinicians provide a more appropriate treatment decision in such cases.

Vestibular Incision Subperiosteal Tunnel Access Technique with Platelet-Rich Fibrin Compared to Subepithelial Connective Tissue Graft for the Treatment of Multiple Gingival Recessions: A Randomized Controlled Clinical Trial

BACKGROUND

The aim of this study was to compare the effectiveness of root coverage through vestibular incision subperiosteal tunnel access (VISTA) technique using platelet rich fibrin (PRF) or subepithelial connective tissue graft (SCTG) in multiple gingival recessions.

MATERIALS AND METHODS

A total of 20 patients with multiple gingival recessions were included, and 10 subjects were randomly allocated to test group (VISTA with PRF) and 10 patients to control group (VISTA with SCTG). Clinical parameters were recorded at baseline, 3 months, and 6 months. Patient's response toward the treatment was also assessed by questionnaire.

RESULTS

All the clinical parameters in the study have showed better results in test group when compared to control group after a follow up period of 6 months with statistical significance.

CONCLUSION

The results of the present study suggested that multiple gingival recessions can be successfully treated with both procedures, but better root coverage and a greater increase in keratinized tissue were achieved with the VISTA technique with SCTG. All the patients in both groups felt it was worth undergoing the treatment.

Tensile strength, growth factor content and proliferation activities for two platelet concentrates of platelet-rich fibrin and concentrated growth factor

Background/purpose

Platelet-rich fibrin (PRF) can be obtained by centrifuging fresh blood in the absence of anticoagulants. Varying the centrifugation speeds may produce tougher and richer concentrated growth factors (CGF). This study examines tensile strength, growth factor content, and the potential of CGF and PRF in promoting periodontal cell proliferation.

Materials and methods

Blood (40 mL/subject) was collected from 44 healthy subjects. PRF and CGF were prepared by centrifuging at 3000 rpm and switching speeds ranging within 3000 rpm, respectively. Fibrin strip was prepared and its tensile strength was measured. Transforming growth factor beta 1 (TGF-β1), platelet-derived growth factor BB (PDGF-BB), and epidermal growth factor (EGF) in the residual serum and fibrin clots were determined by enzyme-linked immunosorbent assay, and their effects on the proliferation of hFOB1.19 osteoblasts and human gingival fibroblasts were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay.

Results

Compared with PRF, tensile strength of CGF was significantly higher. Concentrations and amounts of PDGF-BB and EGF in CGF were significantly higher than those in PRF. Osteoblast number was significantly higher in the cultures with fetal bovine serum (FBS, 10%) and with PRF or CGF fibrin clots (5%, 10%, and 50%) compared to that without FBS. Moreover, osteoblast number in CGF, regardless of the preparation of 10% and 50%, was significantly greater than that in PRF. Similar findings were also observed for gingival fibroblasts among the various subjects.

Conclusion

Varying centrifugation speeds can modify the tensile strength and biological activities of platelet fibrin clots.

Platelet-Rich Fibrin in Coverage of Gingival Recession: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis sought to evaluate the efficacy of platelet-rich fibrin (PRF) membranes versus subepithelial connective tissue grafts (SCTGs) in the coverage of Miller class I and II gingival recessions. After the inclusion and exclusion criteria were applied, the quality of seven articles (Cohen's Kappa = 0.9) was evaluated using the Jadad scale. The MEDLINE/PubMed, Cochrane, and Web of Science databases were consulted, and manual searches were performed in the most popular periodontics journals. The studies included considered a total of 122 patients, 203 surgical fields on which SCTGs were used, and 205 surgical fields on which PRF was used. The parameters analyzed were probing depth, clinical attachment level, gingival recession, and keratinized mucosa. The minimum follow-up period accepted was 6 months. A statistically significant difference between the SCTG and PRF groups was found only in the case of keratinized mucosa. However, gingival recession, clinical attachment level, and probing depth parameters in the PRF group were found to be statistically equal to those of the SCTG group (the gold standard) (p ≥0.05). PRF membranes were determined to be a promising alternative to autogenous gingival grafts in the treatment of Miller class I and II gingival recessions.

Clinical evaluation of injectable platelet-rich fibrin with connective tissue graft for the treatment of deep gingival recession defects: A controlled randomized clinical trial

AIM

The aim of this study was to determine whether the combined connective tissue graft (CTG) with injectable platelet-rich fibrin (i-PRF) with coronally advanced flap (CAF) improved root coverage of deep Miller Class I or II gingival recessions compared with CTG alone with CAF.

MATERIAL AND METHODS

Seventy-two patients with Miller class I and II gingival recessions were enrolled. Thirty-six patients were randomly assigned to the test group (CAF+CTG+i-PRF [700 rpm for 3 min]) or control group (CAF+CTG). Clinical evaluations were made at 6 months.

RESULTS

At 6 months, complete root coverage was obtained at 88% of the sites treated with CAF+CTG+i-PRF and 80% of the sites treated with CAF+CTG. Difference between the two groups was not statistically significant. At 6 months, the recession depth (RD) reduction and increase in keratinized tissue height (KTH) of the test sites were significantly better compared with the control sites.

CONCLUSIONS

According to the results, the addition of i-PRF to the CAF+CTG treatment showed further development in terms of increasing the KTH and decreasing RD. However, this single trial is not sufficient to advocate the true clinical effect of i-PRF on recession treatment with CAF+CTG and additional trials are needed.

Critical Review: What Cell Types Are the Lung Telocytes?

Telocytes (TCs) are stromal cells defined by peculiar long, thin, moniliform prolongations known as telopodes. When isolated, their morphology often lacks the specificity for the proper definition of a particular cell type. Recent studies have linked TCs with different functions and different cell lineages. Although some authors have studied pulmonary TCs, their research has important limitations that we will attempt to summarize in this article. We will focus our analysis on the following: the culture methods used to study them, the lack of proper discrimination of TCs from lymphatic endothelial cells (LECs), whose ultrastructures are very similar, and the immune phenotype of TCs, which may appear in other cell types such as those related to the endothelial lineage or stem/progenitor cells. In conclusion, the cellular diagnosis of lung TCs should be considered with caution until properly designed studies can positively identify these cells and differentiate them from other cell types such as LECs and stem/progenitor cells. Anat Rec, 303:1280-1292, 2020. © 2019 American Association for Anatomy.

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.

The use of platelet-rich fibrin with platelet-rich plasma support meniscal repair surgery

Introduction

Platelet-rich fibrin (PRF) is the only autologous blood product that releases growth factors and has scaffolding properties. We hypothesized that the use of PRF and Platelet-rich plasma (PRP) would improve operative results, including the recovery of function and repaired meniscus.

Materials and Methods

Seventeen patients underwent arthroscopic meniscus repair with PRF and PRP (PRF group) using our novel device for the injection of the PRF into the joint. Another five patients as a control group underwent meniscal repair without PRF and PRP (non-PRF group). The groups were compared in terms of clinical results (Tegner Activity Level Scale, Lysholm Knee Scoring Scale, and International Knee Documentation Committee [IKDC] scores) and changes in magnetic resonance imaging (MRI) findings before surgery and 6 months after surgery.

Results

The Lysholm and IKDC scores improved in all patients postoperatively. However, there was no significant differencies in the postoperative score between the PRF group and the non-PRF group. Follow-up MRI findings did not clearly show improvements.

Conclusions

PRF and PRP are autologous, safe, and cost-effective sources of growth factors. Therefore, we propose a new application of PRF and PRP for autologous transplantation in meniscus repair surgery.

The effect of L-PRF membranes on bone healing in rabbit tibiae bone defects: micro-CT and biomarker results

More insight into the biological fundamentals of leukocyte platelet-rich fibrin (L-PRF) guided healing is necessary to recommend its application, in particular in deficient bone sites that need to support implants. This study investigated the short-term bone healing effect of L-PRF treatment in cylindrical non-critical sized bone defects with 3 mm diameter and 6 mm depth in tibiae of 18 adult male New Zealand White rabbits. After a randomization process, 96 bone defects were prepared and half of them were filled with a L-PRF membrane, while untreated defects in the opposite tibia served as control group. The rabbits were euthanized after 7, 14 or 28 days of healing. The bone healing of the cortical and medullary areas was investigated by micro-CT, while the expression of molecular markers (RUNX2, VEGFA, COL1A2 and BMP2) was assessed by qRT-PCR. Treatment with L-PRF did not affect the micro-structural bone characteristics of the repaired bone tissue, except for a decrease in the trabecular connectivity at the cortical level after 14 days of healing. At this time, RUNX2 and VEGFA mRNA levels were significantly lower in the treated defects. L-PRF membranes thus had a temporary negative influence on the bone microarchitecture (Tb.Pf) and on the RUNX2 and VEGFA expression during early bone healing. Overall, L-PRF treatment did not enhance bone regeneration in these non-critical size defects after 28 days.