Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)

Effectiveness of platelet-rich plasma in partial-thickness rotator cuff tears: a systematic review

IMPORTANCE

Partial-thickness rotator cuff tears (PTRCTs) commonly affect overhead athletes, leading to a decline in sports performance. Platelet-rich plasma (PRP) is being explored as an alternative treatment modality for individuals with PTRCTs to reduce discomfort and enhance functional recovery. We conducted a systematic review study of randomized controlled clinical trials to determine the effectiveness of PRP in treating PTRCTs.

AIM

To determine the effectiveness of PRP in treating PTRCTs.

EVIDENCE REVIEW

We conducted a comprehensive literature search for randomized controlled trials (RCTs) that compared the effectiveness of PRP with eccentric exercise and placebo injections as treatments for PTRCTs. We searched databases such as the Cochrane Library, Web of Science, PubMed, and EMBASE. The visual analog scale (VAS) score, American Shoulder and Elbow Surgeon (ASES) score, and Constant-Murley Score (CMS) was utilized as an outcome measure. Statistical analysis was performed using RevMan 5.3 software.

FINDINGS

Our meta-analysis included 12 studies involving 762 patients. At six weeks post-treatment, the PRP group had significantly higher VAS scores compared to the control group, indicating improvement (standard mean difference (SMD): -2.04 [95% confidence interval (CI): -4.00 to -0.08], I2 ​= ​97%, P-value ​= ​0.04). Patients who received PRP showed statistically significant improvements in VAS scores at 3 months and 6 months follow-up (SMD, -1.78 [95% CI: -3.03 to -0.52], I2 ​= ​96%, P-value ​= ​0.005) (SMD: -2.26 [95% CI: -3.77 to -0.76], I2 ​= ​97%, P-value ​= ​0.003). A statistically significant difference was also observed in VAS scores at the long-term 1-year follow-up (SMD: -2.27 [95% CI: -4.07 to -0.47]; I2 ​= ​98%; P-value ​= ​0.031). There were statistically significant differences in ASES scores and CMS scores in the short-term (SMD: 1.21 [95% CI: 0.19 to 2.24], I2 ​= ​96%, P-value ​= ​0.02) (SMD, 2.01 [95% CI: 0.14 to 3.88], I2 ​= ​97%, P-value ​= ​0.04). However, in the long-term ASES and CMS scores did not show any statistical significance (SMD: 2.06 [95% CI: -0.54 to 4.65], I2 ​= ​99%, P-value ​= ​0.12) (SMD: 4.36 [95% CI: -5.48 to 14.21], I2 ​= ​99%, P-value ​= ​0.39).

CONCLUSIONS AND RELEVANCE

Our findings suggest that PRP treatment is effective in reducing pain for individuals with PTRCTs, providing benefits in the short and long term. However, its impact on functional recovery appears somewhat constrained and doesn't endure over time. Additionally, significant heterogeneity exists among studies, encompassing variations in PRP composition and control group treatments. Consequently, we conclude that compelling evidence for symptom improvement in PTRCT patients following PRP treatment remains elusive.

LEVEL OF EVIDENCE

Level I.

PRF Lysates Modulate Chemokine Expression in Oral Squamous Carcinoma and Healthy Epithelial Cells

Platelet-rich fibrin (PRF), originally used to support soft tissue healing, is also considered a therapeutic option for treating oral lichen planus and leukoplakia. The progression from the two premalignant lesions to the aggressive malignant oral squamous cell carcinoma involves an inflammatory process linked to chemokine expression. Thus, there is a rationale for studying how PRF modulates the expression of chemokines in oral squamous carcinoma cells. To this aim, we expose the oral squamous carcinoma cell line HSC2 to IL1β and TNFα either alone or in the presence of lysates obtained from solid PRF membranes. We report here that in HSC2 cells, PRF lysates significantly reduce the forced transcription of chemokines, e.g., CXCL1, CXCL2, CXCL8, CXCL10, and CCL5. Moreover, PRF lysates attenuate the nuclear translocation of p65 in HSC2 oral epithelial cells when exposed to IL1β and TNFα. PRF lysates further reduce chemokine expression provoked by poly:IC HMW. Even though less pronounced, PRF lysates reduce IL1β- and TNFα-induced chemokine expression in TR146 cells. In primary oral epithelial cells, however, PRF lysates increase the basal expression of CXCL1, CXCL2 and CXCL8. Thus, PRF can exert a biphasic effect on chemokine expression in oral squamous cell carcinoma cell lines and primary oral epithelial cells. These findings suggest that PRF may reduce inflammation in a malignant environment while provoking an immunological response in healthy oral epithelium.

Profound Properties of Protein-Rich, Platelet-Rich Plasma Matrices as Novel, Multi-Purpose Biological Platforms in Tissue Repair, Regeneration, and Wound Healing

Autologous platelet-rich plasma (PRP) preparations are prepared at the point of care. Centrifugation cellular density separation sequesters a fresh unit of blood into three main fractions: a platelet-poor plasma (PPP) fraction, a stratum rich in platelets (platelet concentrate), and variable leukocyte bioformulation and erythrocyte fractions. The employment of autologous platelet concentrates facilitates the biological potential to accelerate and support numerous cellular activities that can lead to tissue repair, tissue regeneration, wound healing, and, ultimately, functional and structural repair. Normally, after PRP preparation, the PPP fraction is discarded. One of the less well-known but equally important features of PPP is that particular growth factors (GFs) are not abundantly present in PRP, as they reside outside of the platelet alpha granules. Precisely, insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) are mainly present in the PPP fraction. In addition to their roles as angiogenesis activators, these plasma-based GFs are also known to inhibit inflammation and fibrosis, and they promote keratinocyte migration and support tissue repair and wound healing. Additionally, PPP is known for the presence of exosomes and other macrovesicles, exerting cell-cell communication and cell signaling. Newly developed ultrafiltration technologies incorporate PPP processing methods by eliminating, in a fast and efficient manner, plasma water, cytokines, molecules, and plasma proteins with a molecular mass (weight) less than the pore size of the fibers. Consequently, a viable and viscous protein concentrate of functional total proteins, like fibrinogen, albumin, and alpha-2-macroglobulin is created. Consolidating a small volume of high platelet concentrate with a small volume of highly concentrated protein-rich PPP creates a protein-rich, platelet-rich plasma (PR-PRP) biological preparation. After the activation of proteins, mainly fibrinogen, the PR-PRP matrix retains and facilitates interactions between invading resident cells, like macrophages, fibroblast, and mesenchymal stem cells (MSCs), as well as the embedded concentrated PRP cells and molecules. The administered PR-PRP biologic will ultimately undergo fibrinolysis, leading to a sustained release of concentrated cells and molecules that have been retained in the PR-PRP matrix until the matrix is dissolved. We will discuss the unique biological and tissue reparative and regenerative properties of the PR-PRP matrix.

Growth factor and cytokine characterization of canine platelet lysate with variable leukocyte concentration, plasma content, and heat-sensitive proteins

Background

Platelet lysate is an acellular platelet product containing factors released from secretory granules, including cytokines and growth factors. This study aimed to evaluate different centrifugation methods used to prepare canine platelet lysate with variable content of leukocytes, plasma, and heat-sensitive proteins.

Methods

Whole blood was collected from six dogs and two double-spin preparation methods were used to generate the platelet-rich plasma with reduced (PRP) and high (L-PRP) concentration of leukocytes. A portion of both methods underwent plasma depletion via centrifugation and platelet lysate was generated via freeze-thaw cycles. A portion of the generated platelet lysate underwent complement inactivation via heat treatment. Growth factors (TGF-β1, VEGF, TNF-α, PDGF-BB, HGF) were quantified in all different platelet lysate preparations using ELISAs.

Results

Both platelet-rich plasma preparations had a 6.7-fold increase in platelet concentration. White blood cell (WBC) concentration compared to whole blood increased 1.2-fold times in PRP and 1.9-fold times in L-PRP. Negligible concentrations of platelets, WBC, and hematocrit were identified in all lysate groups. Statistically significant differences were identified for PDGF, VEGF, and TNF-α, and not for TGF-β or HGF. No growth factor differences were noted between centrifugation methods. PDGF was significantly higher in platelet lysate that was plasma depleted. VEGF was significantly higher in heat-treated lysate groups. TNF-α concentrations were overall very low, though were noted to significantly increase following plasma depletion.

Conclusion

These results support that growth factors and cytokine release can be affected by the platelet lysate preparation and processing.

The impact of submucosal PRP injection on wound healing after endoscopic sinus surgery: a randomized clinical trial

PURPOSE

Chronic rhinosinusitis (CRS) is a prevalent chronic disease observed on a global scale. The utilization of endoscopic sinus surgery (ESS) has gained significant recognition as an effective intervention for individuals with CRS and nasal polyps who have not responded to conventional treatments. The need (or not) for revision surgery frequently relies on the promotion of optimal wound healing. The impact of platelet-rich plasma (PRP) on tissue healing has been extensively examined in various surgical fields.

METHODS

The present prospective study involved 30 patients suffering with nasal polyposis who underwent endoscopic sinus surgery. 15 patients were assigned to the PRP group, and 15 patients to the control group. The clinical follow-up of the patients took place at specific intervals, at weeks 1, 2, 3, 4, 8, and 12 after the surgical procedure. The evaluator identified the existence of adhesions, crusting, bleeding, granulation and infection using a visual analogue scale score. The patients also completed the SNOT 22 questionnaire prior to surgery and at each postoperative visit.

RESULTS

The present study observed a lower incidence of adhesion, infection, hemorrhage and granulation in the PRP group. Furthermore, a statistically significant difference was detected between the groups.

CONCLUSION

Based on the findings of the present investigation, it seems that platelet-rich plasma (PRP) is beneficial on wound healing during the early stages following the surgical procedure. The technique is characterized by its limited invasiveness, which contributes to its low risk profile and the achievement of clinically good outcomes.

A New Experimental Technique for Complete Extraction of Mandibular First Molar Teeth in Rats

Intact extraction of the mandibular first molar tooth is an interesting model for studies of alveolar bone healing. The aim of this study was to describe a new experimental technique for extraction of rat mandibular first molar teeth with crown and all 4 roots intact using controlled forces applied to the teeth. One hundred and twenty female Sprague-Dawley rats were used from a center for experimental animal research. Animals underwent general anesthesia and were then placed in a special dental unit (designed by Moghadam) for the extraction of rat teeth. After syndesmotomy, luxation of the tooth began with a tipping movement in the buccal direction with a very low range of motion for 1 s. A tipping movement in the lingual direction was then used to continue luxation. After a maximum of 10 repetitions, the tooth was left alone for 30 s. After 3-4 stages of this cycle, the tooth loosened. To complete the luxation, the same forces were applied in the buccal and lingual directions with larger amplitude for 3 s. After this step, the tooth was loose enough to be easily extracted. The alveolus was then sutured closed. The results showed no hemorrhage or fracture of crowns and mesial or distal roots, and only 8% of the buccal and lingual roots fractured. The technique designed and used in this study was shown to be an effective model for complete molar tooth extraction in the rat. This technique could also be used in the treatment of other rodents.

Recent advances in the adjunctive management of diabetic foot ulcer: Focus on noninvasive technologies

Diabetic foot ulcer (DFU) is one of the most costly and serious complications of diabetes. Treatment of DFU is usually challenging and new approaches are required to improve the therapeutic efficiencies. This review aims to update new and upcoming adjunctive therapies with noninvasive characterization for DFU, focusing on bioactive dressings, bioengineered tissues, mesenchymal stem cell (MSC) based therapy, platelet and cytokine-based therapy, topical oxygen therapy, and some repurposed drugs such as hypoglycemic agents, blood pressure medications, phenytoin, vitamins, and magnesium. Although the mentioned therapies may contribute to the improvement of DFU to a certain extent, most of the evidence come from clinical trials with small sample size and inconsistent selections of DFU patients. Further studies with high design quality and adequate sample sizes are necessitated. In addition, no single approach would completely correct the complex pathogenesis of DFU. Reasonable selection and combination of these techniques should be considered.

Platelet-rich plasma intra-articular knee injections from open preparation techniques do not pose a higher risk of joint infection: A systematic review of 91 randomized controlled trials and 5914 injections

Purpose

To compare the infection rate of intraarticular platelet-rich plasma (PRP) knee injections between open and closed techniques in randomized controlled trials (RCTs) published in the last decade.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed, Scopus and Virtual Health Library were accessed in October 2022 using the terms 'platelet-rich plasma', 'PRP', 'knee' and 'tibiofemoral' alone and in combination with Boolean operators AND/OR. RCTs published during the last 10 years evaluating PRP intra-articular knee injections were considered eligible. Studies were excluded if the kit/preparation technique was not described. Data were presented using individual studies' absolute values, totals, and pooled percentages. Publication bias was assessed using the ROBIS tool.

Results

Ninety-one studies met the predetermined eligibility criteria. Forty-one implemented a closed technique, while 50 were open. All studies implementing a closed technique disclosed their commercial kits. Only 16 studies (17.58%) failed to report joint infections. Among the studies reporting joint infections as outcomes, 30 implemented a closed technique with 1195 patients, 1921 intra-articular knee injections and 95.44% of patient follow-up. On the other hand, 45 of them implemented an open technique with 2290 patients, 3993 intra-articular knee injections and 97.07% of patient follow-up. No patient had a joint infection among the included studies. Thirty-three studies prepared their PRP in controlled environments (36.26%). Most studies did not report where the preparation occurred (48.35%). Only twelve studies disclosed using laminar flow during preparation (13.19%). The infection rate for both techniques was 0 per 1000 knee injections.

Conclusion

Open PRP preparation techniques do not pose a higher risk of joint infection and can lower manufacturing costs when appropriate facilities are available. However, PRP preparation setting and laminar flow implementation data are deficient, and minimal requirements for good manufacturing practices demand further studies while adhering to local and regional regulations.

Level of Evidence

Level I, systematic review of RCTs.

Tomographic assessment of bone changes in atrophic maxilla treated by split-crest technique and dental implants with platelet-rich fibrin and NanoBone® versus platelet-rich fibrin alone: Randomized controlled trial

BACKGROUND

This study evaluated the clinical benefits of adding NanoBone® with split-crest technique and simultaneous implant placement covered with platelet-rich fibrin membrane in horizontally deficient maxillary ridges in terms of crestal and horizontal bone changes and patient morbidity.

METHODS

Forty patients indicated for maxillary ridge splitting and simultaneous implant placement were assigned randomly to the study groups: control group (Platelet Rich Fibrin membrane) and test group (Platelet Rich Fibrin membrane + Nanobone®). The Cone Beam Computed Tomography Fusion technique was utilized to assess crestal and horizontal bone changes after five months of the surgical procedure. Patient morbidity was recorded for one week post-surgical.

RESULTS

Five months post-surgical, buccal crestal bone resorption was 1.26 ± 0.58 mm for the control group and 1.14 ± 0.63 mm for the test group. Lingual crestal bone resorption was 1.40 ± 0.66 mm for the control group and 1.47 ± 0.68 mm for the test group. Horizontal bone width gain was 1.46 ± 0.44 mm for the control group and 1.29 ± 0.73 mm for the test group. There was no significant statistical difference between study groups regarding crestal and horizontal bone changes and patient morbidity.

CONCLUSIONS

The tomographic assessment of NanoBone® addition in this study resulted in no statistically significant difference between study groups regarding crestal and horizontal bone changes and patient morbidity. More randomized controlled clinical trials on gap fill comparing different bone grafting materials versus no grafting should be conducted.

CLINICALTRIALS

GOV REGISTRATION NUMBER

NCT02836678, 13th January 2017.

Short-Term Effects of Two COX-2 Selective Non-Steroidal Anti-Inflammatory Drugs on the Release of Growth Factors and Cytokines from Canine Platelet-Rich Gel Supernatants

(1) Background: There is a lack of knowledge about how a single dose of COX-2 selective non-steroidal anti-inflammatory drugs (NSAIDs) might affect the release of growth factors (GFs) and cytokines from canine platelet-rich gels (PRGs) and other hemocomponents. (2) Methods: A crossover study was conducted in six adult mongrel dogs. Animals were randomized to receive a single dose of either carprofen or firocoxib. PRG, temperature-induced platelet lysate (TIPL), chemically induced PL (CIPL), and plasma hemocomponents were obtained from each dog before (1 h) and after (6 h) the treatments. Platelet and leukocyte counts and determination of the concentrations of platelet-derived growth factor-BB, (PDGF-BB), transforming growth factor beta-1 (TGF-β1), interleukin 1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and IL-10 concentrations were assayed by ELISA in all hemocomponents. (3) Results: Both platelet and leukocyte counts and PDGF-BB concentrations were not affected by NSAIDs and time. Total TGF-β1 concentrations were not affected by NSAIDs; however, the release of this GF was increased in PRG supernatants (PRGS) at 6 h. IL-1β and TNF-α concentrations were significantly (p < 0.001) lower in both firocoxib PRGS and plasma at 6 h, respectively. IL-10 concentrations were significantly (p < 0.001) lower at 6 h in all hemocomponents treated with both NSAIDs. (4) Conclusions: The clinical implications of our findings could indicate that these drugs should be withdrawn from patients to allow their clearance before the clinical use of PRP/PRG. On the other hand, the prophylactic use of NSAIDs to avoid the inflammatory reactions that some patients might have after PRP/PRG treatment should be performed only in those animals with severe reactive inflammation to the treatment.

Advances in regenerative rehabilitation in the rehabilitation of musculoskeletal injuries

In the rapidly advancing field of regenerative medicine, relying solely on cell transplantation alone may be insufficient for achieving functional recovery, and rehabilitation before and after transplantation is crucial. Regenerative rehabilitation functions by synergizing the therapeutic effects of regeneration and rehabilitation to maximize tissue regeneration and patient function. We used the keywords "regenerative rehabilitation" to search across the database for published works; this review discusses the development of regenerative rehabilitation for the treatment of musculoskeletal injuries. Rehabilitation has become a crucial component of regenerative medicine because it can enhance patients' functional activity and facilitate their early return to society. Experimental data increasingly demonstrates that rehabilitation interventions support the regeneration of transplanted tissues.

Not all platelet-rich plasma are created equal

PURPOSE OF REVIEW

This review aims to elucidate potential variations in clinical outcomes resulting from the use of different types of platelet-rich plasma (PRPs) in reproductive medicine. It seeks to explore the reasons behind the diverse results reported in various studies and assess the general features distinguishing different PRP formulations.

RECENT FINDINGS

PRPs have found applications across diverse medical fields, generating controversy due to the variability in outcomes. The field of reproductive medicine, despite its limited published studies, is encountering a similar challenge as it integrates these treatments.

SUMMARY

The multitude of PRP product brands in the market, coupled with 'home-made' PRPs, poses a significant barrier to establishing a common protocol for the preparation of standardized PRP products. This impediment hinders widespread adoption by clinicians, particularly in endometrial or ovarian treatments. Drawing from evidence in other medical disciplines, this review endeavors to compile essential characteristics that PRPs must possess, aiming to mitigate the impact of variables affecting results in forthcoming studies.

Nanobioactive Blood-Derived Shear-Thinning Biomaterial for Tissue Engineering Applications

The conventional technique for successful bone grafts, involving the use of a patienťs own tissue (autografts), is challenged by limited availability and donor site morbidity. While allografts and xenografts offer alternatives, they come with the risk of rejection. This underscores the pressing need for tailor-made artificial bone graft materials. In this context, injectable hydrogels are emerging as a promising solution for bone regeneration, especially in complex maxillofacial reconstruction cases. These hydrogels can seamlessly adapt to irregular shapes and conservatively fill defects. Our study introduces a shear-thinning biomaterial by blending silicate nanoplatelets (SNs) enriched with human blood-derived plasma rich in growth factors (PRGF) for personalized applications. Notably, our investigations unveil that injectable hydrogel formulations comprising 7.5% PRGF yield sustained protein and growth factor release, affording precise control over critical growth factors essential for tissue regeneration. Moreover, our hydrogel exhibits exceptional biocompatibility in vitro and in vivo and demonstrates hemostatic properties. The hydrogel also presents a robust angiogenic potential and an inherent capacity to promote bone differentiation, proven through Alizarin Red staining, gene expression, and immunostaining assessments of bone-related biomarkers. Given these impressive attributes, our hydrogel stands out as a leading candidate for maxillofacial bone regeneration application. Beyond this, our findings hold immense potential in revolutionizing the field of regenerative medicine, offering an influential platform for crafting precise and effective therapeutic strategies.

Autologous fat grafting for postoperative breast reconstruction: A systemic review

Autologous fat grafting technology has become a new method for breast reconstruction after breast surgery due to its advantages of simple operation, low immunogenicity, fewer complications, high patient acceptance, and natural filling effect. However, the unpredictable fate of transplanted fat limits its widespread application. Currently, many studies have made certain progress in improving the survival rate of fat grafts. This article provides an overview of autologous fat grafting technology, including the mechanisms of fat graft survival, techniques for obtaining and transplanting adipose tissue, methods for enhancing graft survival, and complications associated with fat grafting.

The effectiveness of autologous platelet concentrates in prevention and treatment of medication-related osteonecrosis of the jaws: A systematic review

The systematic review aims to answer the PICOS question: "Are the autologous platelet concentrates (APCs) an effective strategy in prevention and/or treatment of patients at risk of/affected by medication-related osteonecrosis of the jaws (MRONJ)?". A literature search was conducted via PubMed, MEDLINE, EMBASE, and CINAHL (January 2006 - September 2023). 30 articles were included, evaluating preventive (n = 8*) and treatment strategies (n = 23*). The risk of bias and quality of studies were assessed utilising ROB-2, ROBIN-1 and GRADE criteria. Meta-analysis was undertaken for eligible studies. The application of APCs demonstrated a statistically significant effectiveness in prevention of MRONJ in 86.13% (p < 0.001) but failed to achieve the same level of certainty in treatment of established MRONJ in 83.4% (p = 0.08). High levels of bias were identified; thus, the results should be interpreted with caution. More high quality prospective randomised controlled trials are needed to further evaluate the effectiveness of APCs in management of MRONJ.

Mesenchymal stem cells in PRP and PRF containing poly(3-caprolactone)/gelatin Scaffold: a comparative in-vitro study

Scaffold design is one of the three most essential parts of tissue engineering. Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) have been used in clinics and regenerative medicine for years. However, the temporal release of their growth factors limits their efficacy in tissue engineering. In the present study, we planned to synthesize nanofibrous scaffolds with the incorporation of PRP and PRF by electrospinning method to evaluate the effect of the release of PRP and PRF growth factors on osteogenic gene expression, calcification, proliferation, and cell adhesion of human bone marrow mesenchymal stem cell (h-BMSC) as they are part of scaffold structures. Therefore, we combined PRP/PRF, derived from the centrifugation of whole blood, with gelatin and Polycaprolactone (PCL) and produced nanofibrous electrospun PCL/Gel/PRP and PCL/Gel/PRF scaffolds. Three groups of scaffolds were fabricated, and h-BMSCs were seeded on them: (1) PCL/Gel; (2) PCL/Gel/PRP; (3) PCL/Gel/PRF. MTS assay was performed to assess cell proliferation and adhesion, and alizarin red staining confirmed the formation of bone minerals during the experiment. The result indicated that PCL/Gel did not have any better outcomes than the PRP and PRF group in any study variants after the first day of the experiment. PCL/gelatin/PRF was more successful regarding cell proliferation and adhesion. Although PCL/gelatin/PRP showed more promising results on the last day of the experiment in mineralization and osteogenic gene expression, except RUNX2, in which the difference with PCL/gelatin/PRF group was not significant.

Clinical efficacy of titanium prepared platelet rich fibrin in periodontal regeneration: A systematic review and meta-analysis

Background

Periodontal regeneration therapies frequently involve autologous platelet concentrates (APCs). They can be used in sinus lift surgeries and socket preservation, among other clinical settings. Platelet rich fibrin (PRF) membrane has been used to treat gingival recession in individuals or groups of individuals using a coronally progressed or lateral pedicle flap. In the treatment of mixed periodontic endodontic lesion/furcation defect, PRF functions as a healing and interpositional biomaterial, filling a cystic cavity. PRF is known to help the bone regeneration process. In the last few years, efforts have been made to enhance the PRFs characteristics and quality. One of them is titanium platelet rich fibrin (T-PRF). Third-generation platelet concentrate no longer contains silica, and its preparation in glass vacuum containers, that no longer creates any known concerns. The effectiveness PRF's has been evaluated in connective tissue and bone repair. The aim of this study is to compare T-PRF to other platelet concentrates and different treatment modalities for periodontal regenerative procedures.

Methods

A protocol of this systematic review have been registered in prospero (CRD42022293545). The online database searched were PUBMED, COCHRANE for published articles up to November 2022 without language restrictions. Studies in trial registers, handsearching, bibliographic references of relevant articles were also checked. Data collection and analysis was done by individual authors. Independent eligibility assessments were conducted by four review authors. Then, using the standard Cochrane methodology, four review authors extracted the data and evaluated the risk of bias for individual studies. We developed "Summary of findings" tables and used GRADE to evaluate the evidence.

Results

Three studies were included for meta-analysis. Results of meta-analysis supported that T-PRF is effective for correction of both hard and soft tissue defects.

Conclusions

The overall qualitative and quantitative analysis suggest that T-PRF has superior structural properties and thicker fibrin network for ensuring predictable success periodontal regenerative procedures.

Comparison of growth factor levels in injectable platelet-rich fibrin obtained from healthy individuals and patients with chronic periodontitis: a pilot study

BACKGROUND

This study aimed to assess and compare the concentrations of growth factors, white blood cells (WBCs), and platelets in injectable platelet-rich fibrin (i-PRF) derived from people with healthy periodontal conditions and those with chronic periodontitis.

METHODS

Venous blood samples were obtained from 30 patients diagnosed with chronic periodontitis (test group) and 30 participants with healthy periodontal conditions (control group). The i-PRF was then acquired from centrifuged blood. The growth factors (VEGF, IGF-1, TGF-β1, PDGF-BB and EGF) released from the i-PRF samples were compared between groups with ELISA testing. The amounts of WBCs and platelets were also compared.

RESULTS

No significant differences in the concentrations of growth factors were found between the groups (the mean values for the control and test groups were, respectively: IGF: 38.82, 42.46; PDGF: 414.25, 466.28; VEGF: 375.69, 412.18; TGF-β1: 21.50, 26.21; EGF: 138.62, 154.82). The test group exhibited a significantly higher WBC count than the control group (8.80 vs. 6.60, respectively). However, the platelet count did not show a statistically significant difference between the groups (control group 242.0 vs. test group 262.50). No significant correlation was observed between WBC count and growth factor level in either group.

CONCLUSIONS

The growth factor levels in i-PRFs did not exhibit significant difference between the two groups. This suggests that the levels of these growth factors may be unaffected by the periodontal disease.

Treatment of multiple adjacent gingival recessions using leucocyte- and platelet-rich fibrin with coronally advanced flap: a 12-month split-mouth controlled randomized clinical trial

OBJECTIVE

This split-mouth randomized study aimed to assess efficacy of leucocyte-platelet-rich fibrin (L-PRF) versus connective tissue graft (CTG) in achieving root coverage (RC) for multiple adjacent gingival recessions (MAGRs) throughout 12-month period.

MATERIALS AND METHODS

The study enrolled 59 teeth from 12 patients with Miller Class I MAGRs ≥ 2 mm on bilateral or contralateral sides. Patients were randomly assigned to receive coronally advanced flap (CAF) with either CTG (control) or L-PRF (test) treatment. Various parameters, including plaque and gingival index, clinical attachment level, recession depth, probing depth, recession width (RW), papilla width (PW), keratinized tissue width (KTW), gingival thickness (GT), percentage of RC, complete root coverage (CRC), and location of the relative gingival margin concerning the cemento-enamel junctions (GMCEJ) after CAF, were recorded at baseline, 3-, 6-, and 12-months post-surgery. On June 29, 2021 the study was registred to ClinicalTrials.gov (NCT04942821).

RESULTS

Except KTW and GT gain, all clinical parameters, RC, and CRC were similar between the groups at all follow-up periods (p > 0.05). The higher GT and KTW gains were detected in the control group compared to test group at 12 months (p < 0.05). Both RC and CRC were positively associated with initial PW and GMCEJ, but negatively with initial RW (p < 0.05).

CONCLUSIONS

The current study concludes that L-PRF were equally effective as CTG in treating MAGRs in terms of RC and CRC. Additionally, RC and CRC outcomes appeared to be influenced by GMCEJ, PW, and RW.

CLINICAL RELEVANCE

L-PRF could represent a feasible substitute for CTG in treating MAGRs.

The role of platelet-rich plasma in androgenetic alopecia: A systematic review

BACKGROUND

Androgenetic alopecia (AGA), also referred to as male or female pattern hair loss, is the commonest cause of chronic hair loss and affects up to 80% of men by the age of 70. Despite a high prevalence, there are few approved therapies, which show minimal efficacy.

OBJECTIVES

This systematic review aims to evaluate the efficacy of platelet-rich plasma (PrP) in the treatment of AGA in male patients.

METHODS

MEDLINE, EMBASE, Cochrane (CENTRAL), CINAHL, clinicaltrials.gov, Google Scholar and the Science Citation Index database were searched to identify eligible studies. All randomized controlled trials (RCTs) and prospective cohort studies related to PrP use in AGA were included. Primary outcomes included changes in hair density and hair count. Methodological quality was assessed using bias assessment tools.

RESULTS

Eight RCTs and one cohort study were included in the review with a total of 291 participants. Six studies reported a statistically significant increase in hair density in the PrP group versus the control. Five studies reported a statistically significant increase in hair count with PrP. Seven studies showed moderate risk and two showed low risk of bias.

CONCLUSION

In a methodologically robust review on the effectiveness of PrP on male AGA, PrP demonstrated some potential to be used therapeutically. However, the low quality of evidence, moderate risk of bias, and high heterogeneity of included studies limit inferences and call for more robust designs to investigate this further.

The Role of Platelet-Rich Plasma Injection for Muscle Strains in Athletes

Muscle tears/strains are among the most common musculoskeletal injuries, posing a serious challenge for sports medicine. Aiming to reduce the time to return to play and the rate of reinjuries, apart from the traditional conservative treatments and rehabilitation protocols, new and innovative therapeutic options have emerged, particularly platelet-rich plasma (PRP). This study aims to present the available evidence regarding PRP injection for the treatment of muscle strains in athletes. Two databases were searched for articles published between January 2012 and December 2022 in Portuguese or English. The query used for the PubMed database was ("Muscles/injuries"[Mesh]) AND ("Athletes"[Mesh] OR "Athletic Injuries"[Mesh]) AND "Platelet-Rich Plasma"[Mesh], while for the Web of Science database the search was performed for "Platelet-rich plasma" AND "Muscle injuries" AND ("Athletes" OR "Athletic injuries"). Eleven studies involving athletes diagnosed with muscle injuries who received treatment with PRP injection alone, or in combination with traditional conservative treatment, compared to a control group, were included. Four randomized controlled trials, four systematic reviews/meta-analyses, two retrospective studies, and one comparative study were included. Current evidence from the highest-quality studies does not support the hypothesis of reduction of time to return to play and the rate of reinjuries after PRP injection, even though some studies reported positive results. However, the available evidence suggests that PRP might have a beneficial effect on the pain perceived by athletes following an acute muscle strain. It is challenging to arrive at definitive conclusions and translate these findings into a clinical context for treating muscle strains in athletes. The existing trials present several inconsistencies and limitations, with a heterogeneous set of patients and injuries, as well as the use of different and inconsistent methods for preparing, administering, and measuring the effects of PRP. To achieve consistent outcomes, standardizing PRP administration procedures is essential.

From Basic Science to Clinical Practice: A Review of Current Periodontal/Mucogingival Regenerative Biomaterials

Periodontitis is a dysbiosis-driven inflammatory disease affecting the tooth-supporting tissues, characterized by their progressive resorption, which can ultimately lead to tooth loss. A step-wise therapeutic approach is employed for periodontitis. After an initial behavioral and non-surgical phase, intra-bony or furcation defects may be amenable to regenerative procedures. This review discusses the regenerative technologies employed for periodontal regeneration, highlighting the current limitations and future research areas. The search, performed on the MEDLINE database, has identified the available biomaterials, including biologicals (autologous platelet concentrates, hydrogels), bone grafts (pure or putty), and membranes. Biologicals and bone grafts have been critically analyzed in terms of composition, mechanism of action, and clinical applications. Although a certain degree of periodontal regeneration is predictable in intra-bony and class II furcation defects, complete defect closure is hardly achieved. Moreover, treating class III furcation defects remains challenging. The key properties required for functional regeneration are discussed, and none of the commercially available biomaterials possess all the ideal characteristics. Therefore, research is needed to promote the advancement of more effective and targeted regenerative therapies for periodontitis. Lastly, improving the design and reporting of clinical studies is suggested by strictly adhering to the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement.

An Injectable silk-based hydrogel as a novel biomineralization seedbed for critical-sized bone defect regeneration

The healing process of critical-sized bone defects urges for a suitable biomineralization environment. However, the unsatisfying repair outcome usually results from a disturbed intricate milieu and the lack of in situ mineralization resources. In this work, we have developed a composite hydrogel that mimics the natural bone healing processes and serves as a seedbed for bone regeneration. The oxidized silk fibroin and fibrin are incorporated as rigid geogrids, and amorphous calcium phosphate (ACP) and platelet-rich plasma serve as the fertilizers and loam, respectively. Encouragingly, the seedbed hydrogel demonstrates excellent mechanical and biomineralization properties as a stable scaffold and promotes vascularized bone regeneration in vivo. Additionally, the seedbed serves a succinate-like function via the PI3K-Akt signaling pathway and subsequently orchestrates the mitochondrial calcium uptake, further converting the exogenous ACP into endogenous ACP. Additionally, the seedbed hydrogel realizes the succession of calcium resources and promotes the evolution of the biotemplate from fibrin to collagen. Therefore, our work has established a novel silk-based hydrogel that functions as an in-situ biomineralization seedbed, providing a new insight for critical-sized bone defect regeneration.

Autologous platelet-rich plasma for assisted reproduction

BACKGROUND

Autologous platelet-rich plasma (PRP) consists of plasma and a concentrate of platelets extracted from fresh whole blood of the person being treated. Research has suggested that intrauterine or intraovarian infusion/injection of PRP before embryo transfer may improve endometrial receptivity and response to ovarian stimulation in women undergoing assisted reproduction. We compared these interventions to standard treatment, placebo, or other interventions (mechanical or pharmacological).

OBJECTIVES

To assess the effectiveness and safety of intrauterine and intraovarian infusion/injection of platelet-rich plasma in infertile women undergoing assisted reproductive technology cycles.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group's Specialised Register, CENTRAL, MEDLINE, Embase, and the Epistemonikos database in January 2023. We also searched the reference lists of relevant articles and contacted the trial authors and experts in the field for any additional trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated the application of PRP in the uterine cavity, ovaries, or both versus no intervention, placebo, or any other intervention (either mechanical or pharmacological) in women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles.

DATA COLLECTION AND ANALYSIS

We followed standard methodological procedures recommended by Cochrane, including use of the updated risk of bias tool (RoB 2). The primary outcomes were live birth (or ongoing pregnancy) and miscarriage. The secondary outcomes were clinical pregnancy, complications of the procedure, multiple pregnancy, ectopic pregnancy, fetal growth restriction, preterm delivery, and fetal abnormality. We estimated the average effect of the interventions by fitting a Der Simonian-Laird's random-effects meta-analysis model. We reported pooled odds ratios (ORs) with 95% confidence intervals (CIs). We restricted the primary analyses to trials at low risk of bias for the outcomes and performed sensitivity analyses that included all studies.

MAIN RESULTS

We included 12 parallel-group RCTs that recruited a total of 1069 women. We identified three different comparison groups. Using GRADE, we assessed the certainty of evidence as very low for almost all outcomes. Intrauterine injection/infusion of platelet-rich plasma versus no intervention or placebo Nine studies evaluated intrauterine PRP versus no intervention or placebo. Eight included women with at least two or three previous implantation failures. Only one was assessed at low risk of bias for each outcome. This study provided very low-certainty evidence about the effect of intrauterine PRP injection versus no intervention on live birth (OR 1.10, 95% CI 0.38 to 3.14; 94 women) and miscarriage (OR 0.96, 95% CI 0.13 to 7.09; 94 women). If the likelihood of live birth following no intervention is assumed to be 17%, then the likelihood following intrauterine PRP would be 7% to 40%; and if the risk of miscarriage following no intervention is 4%, then the risk following intrauterine PRP would be 1% to 24%. When we analyzed all studies (regardless of risk of bias), we found very low-certainty evidence about the effect of intrauterine PRP compared with placebo or no intervention on live birth or ongoing pregnancy (OR 2.38, 95% CI 1.16 to 4.86; I² = 54%; 6 studies, 564 women) and miscarriage (OR 1.54, 95% CI 0.59 to 4.01; I² = 0%; 5 studies, 504 women). The study at low risk of bias provided very low-certainty evidence about the effect of intrauterine PRP compared with no intervention on clinical pregnancy (OR 1.55, 95% CI 0.64 to 3.76; 94 women) and ectopic pregnancy (OR 2.94, 95% CI 0.12 to 73.95; 94 women). The synthesis of all studies provided very low-certainty evidence about the effect of intrauterine PRP compared with placebo or no intervention on clinical pregnancy (OR 2.22, 95% CI 1.50 to 3.27; I² = 24%; 9 studies, 824 women), multiple pregnancy (OR 2.68, 95% CI 0.81 to 8.88; I² = 0%; 2 studies, 240 women), and ectopic pregnancy (OR 2.94, 95% CI 0.12 to 73.95; 1 study, 94 women; very low-certainty evidence). Intrauterine infusion of PRP may increase the risk of preterm delivery compared with no intervention (OR 8.02, 95% CI 1.72 to 37.33; 1 study, 120 women; low-certainty evidence). No studies reported pain, infection, allergic reaction, fetal growth restriction, or fetal abnormality. Intrauterine infusion of platelet-rich plasma versus intrauterine infusion of granulocyte colony-stimulating factor Two RCTs evaluated intrauterine PRP versus intrauterine granulocyte colony-stimulating factor (G-CSF); both included women with thin endometrium, and neither was judged at low risk of bias for any outcome. We are uncertain about the effect of intrauterine PRP compared with intrauterine G-CSF on live birth (OR 0.88, 95% CI 0.43 to 1.81; 1 study, 132 women; very low-certainty evidence), miscarriage (OR 1.94, 95% CI 0.63 to 5.96; 1 study, 132 women; very low-certainty evidence), and clinical pregnancy (OR 1.24, 95% CI 0.66 to 2.35; 2 studies, 172 women; very low-certainty evidence). Neither study reported adverse outcomes other than miscarriage. Intraovarian injection of platelet-rich plasma versus no intervention One RCT evaluated PRP injection into both ovaries versus no intervention; it was judged at high risk of bias for the two outcomes it reported. We are uncertain about the effect of intraovarian PRP injection compared with no intervention on ongoing pregnancy (OR 1.09, 95% CI 0.33 to 3.63; 73 women; very low-certainty evidence) and clinical pregnancy (OR 0.90, 95% CI 0.31 to 2.60; 73 women; very low-certainty evidence). The study examined no safety outcomes.

AUTHORS' CONCLUSIONS

We are uncertain about the effect of intrauterine or intraovarian administration of PRP on outcomes of assisted reproduction technology in infertile women. The pooled results should be interpreted with caution. Only one of the 12 included studies was judged at low risk of bias. Other limitations of the included trials were failure to report live birth, poor reporting of methods, lack of prospective protocol registration, low precision due to the small number of enrolled participants, indirectness due to the specific subpopulations and settings studied, and insufficient or absent safety data.

Platelet-rich fibrin as an autologous biomaterial for bone regeneration: mechanisms, applications, optimization

Platelet-rich fibrin, a classical autologous-derived bioactive material, consists of a fibrin scaffold and its internal loading of growth factors, platelets, and leukocytes, with the gradual degradation of the fibrin scaffold and the slow release of physiological doses of growth factors. PRF promotes vascular regeneration, promotes the proliferation and migration of osteoblast-related cells such as mesenchymal cells, osteoblasts, and osteoclasts while having certain immunomodulatory and anti-bacterial effects. PRF has excellent osteogenic potential and has been widely used in the field of bone tissue engineering and dentistry. However, there are still some limitations of PRF, and the improvement of its biological properties is one of the most important issues to be solved. Therefore, it is often combined with bone tissue engineering scaffolds to enhance its mechanical properties and delay its degradation. In this paper, we present a systematic review of the development of platelet-rich derivatives, the structure and biological properties of PRF, osteogenic mechanisms, applications, and optimization to broaden their clinical applications and provide guidance for their clinical translation.

Therapeutic roles of platelet-rich plasma to restore female reproductive and endocrine dysfunction

Millions of women worldwide are infertile due to gynecological disorders, including premature ovarian insufficiency, polycystic ovary syndrome, Asherman syndrome, endometrial atrophy, and fallopian tube obstruction. These conditions frequently lead to infertility and have a substantial impact on the quality of life of the affected couples, primarily because of their psychological implications and high financial costs. Recently, using platelets to stimulate cell proliferation and tissue differentiation has emerged as a promising approach in regenerative medicine. Platelet-rich plasma (PRP) shows considerable potential for promoting endometrial hypertrophy and follicle development, making it a promising therapeutic option for tissue repair or replacement. This review provides an overview of the recent advancements and underlying mechanisms of PRP therapy for various female reproductive diseases and presents new therapeutic options for addressing female infertility.

Review of Dohan Eherenfest et al. (2009) on "Classification of platelet concentrates: From pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)"

This classic discusses the original publication of Dohan Eherenfest et al. on "Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)", in which the authors propose four categories of platelet concentrates depending on their leucocyte and fibrin content (P-PRP, leucocyte- and platelet-rich plasma (L-PRP), pure platelet-rich fibrin (P-PRF), and L-PRF) to group a "jungle" of products in which the term platelet-rich plasma (PRP) was used indistinctly. They were able to identify common factors such as: (1) the use of anticoagulants and immediate centrifugation of the blood after its collection; (2) most preparation techniques allowed platelet concentrate preparation within an hour; (3) the centrifugation aimed to separate the blood in layers that would allow the extraction of specific fractions; and (4) the product was activated with thrombin or calcium chloride. The reviewed manuscript has been listed among the most cited PRP articles in regenerative medicine, with more than 800 citations, driving current scientific research and clinical practise by categorising L-PRP and P-PRP (now, leucocyte-poor PRP). The classification has also opened the door to understanding intrinsic biological mechanisms between platelets, leukocytes, fibrin, and growth factors, which will later be considered for studying the proliferation and differentiation of cells in different tissues affected by PRP. Since the initial classification of platelet concentrates, several other classification systems have been proposed and published in the current literature such as platelet, activation, white blood cell (PAW), Mishra, platelet, leucocyte, red blood cells, and activation (PLRA), dose of platelet, efficiency, purity, and activation (DEPA), method, activation, red blood cells, spin, platelets, image guidance, leukocytes, and light activation (MARSPILL), etc. These classifications have identified important aspects of PRP that affect the biological composition and, ultimately, the indications and outcomes. To date, there is still a lack of standardisation in sample preparation, cohort heterogeneity, and incomplete reporting of sample preparation utilised, leading to a lack of clarity and challenging researchers and clinicians.

Advancements in Regenerative Medicine for Aesthetic Dermatology: A Comprehensive Review and Future Trends

The growing interest in maintaining a youthful appearance has encouraged an accelerated development of innovative, minimally invasive aesthetic treatments for facial rejuvenation and regeneration. The close correlation between tissue repair, regeneration, and aging has paved the way for the application of regenerative medicine principles in cosmetic dermatology. The theoretical substrates of regenerative medicine applications in dermo-aesthetics are plentiful. However, regenerative dermatology is an emerging field and needs more data and in vivo trials to reach a consensus on the standardization of methods. In this review, we summarize the principles of regenerative medicine and techniques as they apply to cosmetic dermatology, suggesting unexplored fields and future directions.

The activity of monocyte-derived macrophages after stimulation with platelet-rich and platelet-poor concentrates. Study on an ovine model of insertion of a tibial implant coated with silicon-doped diamond-like carbon

Introduction

Macrophages are crucial immune cells that play a role in tissue repair and can exhibit pro- or anti-inflammatory behaviour based on environmental stimulation. Their functional phenotype can be affected by platelet-derived products as determined by those products' composition. When the inflammatory response caused by implantation is excessive, it can lead to rejection of the implant. Therefore, a thorough evaluation of implant haemocompatibility is necessary to minimise undesirable consequences.

Material and Methods

In an in vitro study, monocyte-derived macrophages (MDMs) were obtained from the whole blood of sheep after a silicon-doped diamond-like carbon-coated implant insertion. These MDMs were then exposed to autologous platelet-derived products for functional marker analysis.

Results

Platelet-poor plasma (PPP) and pure platelet-rich plasma (P-PRP) stimulation increased arginase-1 activity, while leukocyte-rich PRP stimulation produced a mixed response involving higher O2- (6.49 ± 2.43 nM vs non-stimulated 3.51 ± 1.23 nM, P-value < 0.05) and NO (3.28 ± 1.38 μM vs non-stimulated 2.55 ± 0.32μM, P-value < 0.05) generation.

Conclusion

Using PPP and P-PRP stimulation in post-implantation procedures may contribute to the polarisation of macrophages towards the M2-like pro-resolving phenotype, thereby accelerating wound healing. This would also prevent implant degradation due to an excessive inflammatory process.

Allogeneic platelet-rich plasma inhibits ferroptosis in promoting wound repair of type 2 diabetic ulcers

Increasing evidence has revealed the emerging role of ferroptosis in the pathophysiology of type 2 diabetes mellitus (T2DM) and its complications. Platelet-rich plasma (PRP) has been demonstrated to facilitate the healing of T2DM ulcers. However, the mechanism by which PRP repairs T2DM ulcers remains unclear. Here, we sought to investigate the interaction between PRP and ferroptosis in repairing T2DM ulcers. The results showed that the cellular activity, proliferation, and migration of fibroblasts were down-regulated, and the cellular activity and normal function of vascular endothelial cells were impaired in the high glucose environment or under RSL3 conditions (a GSH peroxidase 4 inhibitor and ferroptosis inducer). Additionally, both cells experienced over-activation of multiple forms of reactive oxygen species (ROS) and lipid peroxidation. In the T2DM rat model, we observed a decreased rate of ulcer wound healing, impaired proliferative capacity, diminished vascular regeneration, and marked inflammation and hyperfibrosis. More importantly, there was typical damage to mitochondria, increased levels of iron ions, and consistent alterations in protein expression of ferroptosis-related factors. These factors include cyclooxygenase-2 (COX2), glutathione peroxidase 4 (GPX4), transferrin receptor (TFRC), and Solute Carrier Family 7 Member 11 (SLC7A11), among others. Due to the strong association between ferroptosis and T2DM ulcers, the use of allogeneic platelet-rich plasma (Al-PRP) exhibited physiological effects similar to those of the ferroptosis inhibitor Ferrostatin-1 (Fer-1). In vivo experiments, both drugs inhibited a range of impediments to wound healing caused by T2DM and ameliorated the adverse effects associated with ferroptosis. Moreover, Al-PRP attenuated the impairment of normal cellular function, activation of ROS and lipid peroxidation induced by high glucose or RSL3. These results suggested that ferroptosis was involved in the development of T2DM ulcers, which could be treated with Al-PRP by inhibiting ferroptosis, and inhibition of ferroptosis may be a suitable treatment strategy for T2DM ulcers.

Regenerative Medicine Solutions for Rotator Cuff Injuries in Athletes: Indications and Outcomes

Rotator cuff (RC) injuries include a wide range of pathologic states. Athletes are perhaps the most susceptible to RC injuries ranging from tendinopathy to partial or full-thickness tears, due to functional overload and repetitive movements, causing abstention from sports for long periods. Regenerative medicine keeps giving us multiple choices to fight the disability caused by these pathologies. A literature search was performed, and findings related to the structure-function of rotator cuff units, pathophysiology of injuries, regenerative medicine treatments, and future strategies were outlined. Platelet-rich plasma (PRP) has a greater number of articles and clinical trials, accompanied by stem cells progenitor, prolotherapy, and new approaches such as microfragmented adipose tissue and exosomes. RC injuries in athletes can cause pain, functional impotence, and the risk of recurrence, and can lead them to stop playing sports. Regenerative medicine offers a range of treatments, but some of them need further studies to underline their actual validity.

Effect of intranasal administration of concentrated growth factors on regeneration of the olfactory epithelium in an olfactory dysfunction-induced rat model

OBJECTIVE

The development of treatments that promote the regenerative capacity of the olfactory epithelium (OE) is desirable. This study aimed to evaluate the effects of intranasal administration of concentrated growth factors (CGFs) in a rat model of olfactory dysfunction.

STUDY DESIGN

Animal study.

METHODS

Nineteen male rats were used. Fourteen olfactory dysfunction models were created by intraperitoneal administration of 3-methylindole. We randomly divided the rats from the olfactory dysfunction model after 1 week into the CGF or saline group; CGFs were administered to seven animals and saline to seven animals. Behavioral assessments using the avoidance test were conducted until day 28 after CGF/saline administration. On day 28, histological evaluation was conducted to determine olfactory epithelial thickness and the olfactory marker protein (OMP)-positive cell count. Five animals were intraperitoneally injected with saline as the control group.

RESULTS

The avoidance rate remained decreased until 28 days after CGF/saline administration, and there was no significant difference between the two groups. Olfactory epithelial thicknesses on day 28 were 38.64 ± 3.17 μm and 32.84 ± 4.50 μm in the CGF and saline groups, respectively. OE thickness was significantly thicker in the CGF group than in the saline group (P = 0.013). The numbers of OMP-positive cells were 40.29 ± 9.77/1.0 × 104 μm2 and 31.00 ± 3.69/1.0 × 104 μm2 in the CGF and saline groups, respectively. The number of OMP+ cells in the CGF group was significantly increased compared with that in the saline group (P = 0.009). Both groups showed no improvement compared with the control group (OE thickness: 54.08 ± 3.36 μm; OMP+ cell count: 56.90 ± 9.91/1.0 × 104 μm2).

CONCLUSIONS

The CGF group showed improved olfactory epithelial thickness and OMP-positive cell numbers compared with that in the saline group.

Comparative Evaluation of DFDBA versus PRF with DFDBA in Treatment of Grade-II Furcation Defects - A Clinical Trial

Background

In order to determine whether a method is more successful for treating a grade-II furcation deficiency, this randomized trial will compare demineralized freeze-dried bone allograft (DFDBA) to platelet-rich fibrin with DFDBA.

Materials and Methods

Twenty systematically healthy patients between the ages of 30 and 60 with a grade-II furcation were evaluated pre and postoperatively for changes in the modified plaque index, probing depth, relative vertical and horizontal clinical attachment level, gingival marginal level, and radiographic bone defect.

Results

The test group significantly outperformed the control group on all clinical and radiological measures.

Conclusion

The experimental group improved at both clinical attachment levels and had a higher decrease in probing depth than the control group did.

Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology

PURPOSE

To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies.

METHODS

A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement.

RESULTS

There was consensus on 62% of statements about PRP.

CONCLUSIONS

(1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology.

LEVEL OF EVIDENCE

Level V, expert opinion.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

Platelet-rich fibrin in dentistry

OBJECTIVES

To review the progress of Platelet Rich Fibrin (PRF) as a biomaterial in dentistry and to highlight its promising application as a safe and biocompatible autologous platelet concentrate. Publications were searched in GeenMedical, X-mol, GoogleScholar, and PubMed from October 2024 with no language restrictions. The literature was searched for relevant databases and journals on the use of PRFs in dentistry up to October 2024, and the inclusion criteria included randomized controlled trials, clinical trials, case series, and systematic reviews.

CONCLUSION

PRF is a second-generation platelet concentrate that is sourced from oneself, has fewer adverse effects, and is simple and safe to prepare. These materials include growth factors and fibrin scaffolds, which are extensively utilized in regenerative medicine. By outlining PRF, we found that good results can be achieved when PRF is used to treat these conditions.

CLINICAL SIGNIFICANCE

The application of PRF in dentistry is widespread, particularly in periodontal soft and hard tissue regeneration, oral lichen planus, and pulpal regeneration. This article reviews the background, classification, and preparation methods of PRFs, along with their dental applications. We anticipate further research on various PRF derivatives in the future, which will significantly improve the utilization of PRF in oral applications and offer fresh insights for diagnosing and treating oral diseases.

Effect of adjuvant autologous platelet concentrates on secondary repair of alveolar clefts: A systematic review and meta-analysis

OBJECTIVE

To review the existing evidence on the adjuvant use of autologous platelet concentrates (APCs) with iliac crest bone graft (ICBG) in the reconstruction of the secondary alveolar cleft.

METHODS

Electronic databases were searched systematically until November 2022. Clinical trials comparing the three-dimensional radiological outcomes of patients who underwent secondary alveolar bone grafting (SABG) with ICBG and APCs to those with ICBG alone and the radiological outcomes assessed 6 months after surgery were included. Two authors performed the study selection and the assessment of the risk of bias. Meta-analysis was performed using the random-effects model to determine the risk ratio (RR) for developing wound dehiscence and the mean difference (MD) with a 95% confidence interval (CI) for the percentage of newly formed bone.

RESULTS

Nine studies (seven RCT and two CCT) were included with a low to high risk of bias. At the 6-month follow-up, the study group revealed insignificant results regarding the percentage of newly formed bone (MD = 6.49; 95% CI: -0.97, 13.94; p = .09; χ2  = 0.01; I2  = 71%). In addition, the overall risk of developing wound dehiscence was lower in the study group (RR = 0.34; 95% CI: 0.15, 0.78; p = .01; χ2  = 0.67; I2  = 0%).

CONCLUSION

Currently, there is insufficient evidence to support the adjuvant use of APCs with ICBG on enhanced bone regeneration following secondary alveolar bone grafting. However, combining ICBG and APCs might be beneficial in reducing the risk of developing wound dehiscence.

Platelet Concentrates Preconditioning of Mesenchymal Stem Cells and Combined Therapies: Integrating Regenerative Strategies for Enhanced Clinical Applications

This article presents a comprehensive review of the factors influencing the efficacy of mesenchymal stem cells (MSCs) transplantation and its association with platelet concentrates (PCs). It focuses on investigating the impact of PCs' composition, the age and health status of platelet donors, application methods, and environmental factors on the outcomes of relevant treatments. In addition, it delves into the strategies and mechanisms for optimizing MSCs transplantation with PCs, encompassing preconditioning and combined therapies. Furthermore, it provides an in-depth exploration of the signaling pathways and proteomic characteristics associated with preconditioning and emphasizes the efficacy and specific effects of combined therapy. The article also introduces the latest advancements in the application of biomaterials for optimizing regenerative medical strategies, stimulating scholarly discourse on this subject. Through this comprehensive review, the primary goal is to facilitate a more profound comprehension of the factors influencing treatment outcomes, as well as the strategies and mechanisms for optimizing MSCs transplantation and the application of biomaterials in regenerative medicine, offering theoretical guidance and practical references for related research and clinical practice.

Biological and Cellular Properties of Advanced Platelet-Rich Fibrin (A-PRF) Compared to Other Platelet Concentrates: Systematic Review and Meta-Analysis

Platelet concentrates are used for cell induction and stimulation in tissue repair processes. The aim of the present systematic review and meta-analysis was to compare the biological and cellular properties of advanced platelet-rich fibrin (A-PRF) to those of other platelet concentrates. Searches were conducted on the PubMed/Medline, Scopus, Web of Science, Embase and LILACS databases using a search strategy oriented by the guiding question. A total of 589 records were retrieved. Seven articles of in vitro experimental studies were selected for qualitative data analysis and four were selected for meta-analysis. The release of growth factors, distribution of cells in the fibrin membrane, and cell viability, the fibrin network, and fibroblast migration were investigated. In the final analysis, statistically significant differences were found for the A-PRF group with regard to platelet-derived growth factor, transforming growth factor, epidermal growth factor and vascular endothelial growth factor at all assessment times. A difference was found with regard to bone morphogenetic protein only in the later assessment, and no differences among groups were found with regard to platelet-derived growth factor or insulin-like growth factor. The results of this systematic review and meta-analysis suggest that A-PRF has superior cellular properties and better release of growth factors compared to other platelet concentrates.

Platelet-Rich Plasma in Dermatology: New Insights on the Cellular Mechanism of Skin Repair and Regeneration

The skin's recognised functions may undergo physiological alterations due to ageing, manifesting as varying degrees of facial wrinkles, diminished tautness, density, and volume. Additionally, these functions can be disrupted (patho)physiologically through various physical and chemical injuries, including surgical trauma, accidents, or chronic conditions like ulcers associated with diabetes mellitus, venous insufficiency, or obesity. Advancements in therapeutic interventions that boost the skin's innate regenerative abilities could significantly enhance patient care protocols. The application of Platelet-Rich Plasma (PRP) is widely recognized for its aesthetic and functional benefits to the skin. Yet, the endorsement of PRP's advantages often borders on the dogmatic, with its efficacy commonly ascribed solely to the activation of fibroblasts by the factors contained within platelet granules. PRP therapy is a cornerstone of regenerative medicine which involves the autologous delivery of conditioned plasma enriched by platelets. This is achieved by centrifugation, removing erythrocytes while retaining platelets and their granules. Despite its widespread use, the precise sequences of cellular activation, the specific cellular players, and the molecular machinery that drive PRP-facilitated healing are still enigmatic. There is still a paucity of definitive and robust studies elucidating these mechanisms. In recent years, telocytes (TCs)-a unique dermal cell population-have shown promising potential for tissue regeneration in various organs, including the dermis. TCs' participation in neo-angiogenesis, akin to that attributed to PRP, and their role in tissue remodelling and repair processes within the interstitia of several organs (including the dermis), offer intriguing insights. Their potential to contribute to, or possibly orchestrate, the skin regeneration process following PRP treatment has elicited considerable interest. Therefore, pursuing a comprehensive understanding of the cellular and molecular mechanisms at work, particularly those involving TCs, their temporal involvement in structural recovery following injury, and the interconnected biological events in skin wound healing and regeneration represents a compelling field of study.

The Synergistic Effects of Hyaluronic Acid and Platelet-Rich Plasma for Patellar Chondropathy

Musculoskeletal disorders are increasingly prevalent worldwide, causing significant socioeconomic burdens and diminished quality of life. Notably, patellar chondropathy (PC) is among the most widespread conditions affecting joint structures, resulting in profound pain and disability. Hyaluronic acid (HA) and platelet-rich plasma (PRP) have emerged as reliable, effective, and minimally invasive alternatives. Continuous research spanning from laboratory settings to clinical applications demonstrates the numerous advantages of both products. These encompass lubrication, anti-inflammation, and stimulation of cellular behaviors linked to proliferation, differentiation, migration, and the release of essential growth factors. Cumulatively, these benefits support the rejuvenation of bone and cartilaginous tissues, which are otherwise compromised due to the prevailing degenerative and inflammatory responses characteristic of tissue damage. While existing literature delves into the physical, mechanical, and biological facets of these products, as well as their commercial variants and distinct clinical uses, there is limited discussion on their interconnected roles. We explore basic science concepts, product variations, and clinical strategies. This comprehensive examination provides physicians with an alternative insight into the pathophysiology of PC as well as biological mechanisms stimulated by both HA and PRP that contribute to tissue restoration.

The Clinical Application of Platelet-Rich Plasma in the Female Reproductive System: A Narrative Review

Platelet-rich plasma is an autologous plasma containing platelets prepared from fresh whole blood drawn from a peripheral vein. Through processing, it can be prepared to contain supraphysiologic levels of platelets at three to five times greater than the level of normal plasma. PRP has been explored both in vivo and ex vivo in the human endometrium model in its ability to harness the intrinsic regenerative capacity of the endometrium. Intrauterine autologous PRP infusions have been shown to increase endometrial thickness and reduce the rate of intrauterine adhesions. In the setting of recurrent implantation failure, intrauterine infusion of PRP has been shown to increase clinical pregnancy rate. PRP also appears to hold a potential role in select patients with premature ovarian insufficiency, poor ovarian responders and in improving outcomes following frozen-thawed transplantation of autologous ovarian tissue. Further studies are required to explore the potential role of PRP in reproductive medicine further, to help standardise PRP protocols and evaluate which routes of administration are most effective.

Autologous blood products: Leucocyte and Platelets Rich Fibrin (L-PRF) and Platelets Rich Plasma (PRP) gel to promote cutaneous ulcer healing - a systematic review

OBJECTIVE

To summarise evidence on the effectiveness of Platelet-Rich Plasma (PRP) gel and Leucocyte and Platelet Rich Fibrin (L-PRF) gel as agents promoting ulcer healing compared with the standard wound dressing techniques alone.

DESIGN

Systematic review.

ELIGIBILITY CRITERIA

Individual patient randomised controlled trials on skin ulcers of all types excluding traumatic lesions.Intervention group: treatment with topical application of L-PRF gel or PRP gel to the wound surface.

CONTROL GROUP

treatment with standard skin ulcer care using normal saline, normgel or hydrogel dressings.

INFORMATION SOURCES

Medline (Ovid), Excerpta Medica Database (EMBASE), Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Web of Science and manual search of studies from previous systematic reviews and meta-analyses. The papers published from 1946 to 2022 with no restriction on geography and language were included. The last date of the search was performed on 29 August 2022.

DATA EXTRACTION AND SYNTHESIS

Independent reviewers identified eligible studies, extracted data, assessed risk of bias using V.2 of the Cochrane risk-of-bias tool for randomised trials tool and assessed certainty of evidence by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

MAIN OUTCOME MEASURES

Time to complete healing, proportion healed at a given time and rate of healing.

RESULTS

Seven studies met the inclusion criteria, five using PRP gel and two using L-PRF gel. One study showed a better proportion of complete healing, three reported reduced meantime to complete healing and five showed improved rate of healing per unit of time in the intervention group. The risk of bias was high across all studies with one exception and the GRADE showed very low certainty of evidence.

CONCLUSION

The findings show potential for better outcomes in the intervention; however, the evidence remains inconclusive highlighting a large research gap in ulcer treatment and warrant better-designed clinical trials.

PROSPERO REGISTRATION NUMBER

CRD42022352418.

Advanced platelet-rich fibrin promotes healing of induced corneal ulcer in donkeys (Equus asinus)

Ulcerative keratitis is a common disease in horses which may cause blindness. To prevent secondary bacterial and fungal infections and promote quick re-growth of the epithelial layer, different treatment approaches have been employed. This study aimed to examine the effects of advanced platelet-rich fibrin (A-PRF) gel on the healing process of experimentally induced corneal ulcers in donkeys. Nine healthy adult donkeys were used for the study. The donkeys were divided into two groups: the control group, where no medication was applied to the corneal ulcer, and the A-PRF gel group, where A-PRF gel was applied once a day on specific days after ulcer induction. The healing process was evaluated through various examinations and analyses. The results demonstrated that the A-PRF gel group showed significant improvement in the corneal ulcer area, with epithelial and stromal regeneration. At day 35, about 60% of the A-PRF group showed negative fluorescein uptake. Additionally, fewer complications were observed during the healing process compared to the control group. In conclusion, A-PRF gel is an important and safe therapeutic option for controlling ocular surface infection and promoting corneal healing. We recommend using A-PRF gel as an alternative approach, avoiding eyelid suturing, and minimizing corneal irritation.

In Vitro Antimicrobial Properties and Their Mechanisms in Relation to Reactive Oxygen Species of Canine Platelet-Rich Fibrin

Platelet-rich fibrin (PRF), which has been shown to promote wound and bone regeneration, has demonstrated antimicrobial properties against periodontal pathogens. However, in veterinary medicine, no study has determined the antimicrobial effects of canine platelet-rich fibrin (cPRF). Therefore, this study aimed to determine the antimicrobial effect of cPRF against E. coli and S. pseudintermedius found in dogs' wounds and against the standard strain S. aureus. Additionally, the mechanism of the existing antibacterial activity of cPRF, which involves the formation of reactive oxygen species (ROS), was tested. Blood samples from six dogs were processed for cPRF. The antimicrobial properties of three groups (growth control, cPRF, and drug control) were evaluated at 0.5, 4, 8, and 24 h using a time-kill assay. The killing mechanisms involving ROS were evaluated using horseradish peroxidase (HRP) to suppress ROS production in PRF (PRF-SR). Subsequently, tests for antimicrobial properties and ROS generation were compared to those of the growth control and cPRF groups. The results showed that cPRF had significant antimicrobial properties against E. coli but no antimicrobial properties against S. pseudintermedius. After the ROS suppression, PRF-SR did not show an antimicrobial property against E. coli. Moreover, cPRF-treated bacteria exhibited significantly greater intracellular ROS than PRF-SR. In conclusion, canine PRF showed an antimicrobial effect against E. coli, and its antibacterial mechanism was related to releasing ROS.

Efficacy of platelet-rich plasma and platelet-rich fibrin in arthroscopic rotator cuff repair: A systematic review and meta-analysis

OBJECTIVE

Basic scientific studies have demonstrated positive effects of platelet-rich therapies, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), on tendon repair. However, clinical evidence indicating improved prognosis is controversial. In this study, we aimed to determine whether augmentation of arthroscopic rotator cuff repair with PRP and PRF improves outcomes compared to arthroscopic repair alone.

LITERATURE SURVEY

PubMed, Embase, and Cochrane library databases were comprehensively searched for randomized controlled trials (RCTs) published until June 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. No language restriction was applied.

METHODOLOGY

The primary outcomes were the rate of repeat tears after arthroscopic rotator cuff repair (retear rate) and clinical function scores (Constant-Murley Score, University of California, Los Angeles Score), and the extracted data were assessed for quality. Statistical analyses were performed using Review manager 5.3, and p < .05 was considered statistically significant.

SYNTHESIS

Ten RCTs with 628 patients were included. The results showed that augmenting surgery with PRP reduces retear rates compared to surgery alone (risk ratio [RR] = 0.40, 95% confidence interval [CI] 0.23-0.69, p = .001), whereas PRF has no effect on retear rates (p = .92). Regarding clinical function, PRP improves Constant-Murley scores (mean difference [MD] = 2.03, 95% CI 0.13-3.93, p = .04) and University of California, Los Angeles scores (MD = 1.30, 95% CI 0.36-2.24, p = .007), whereas PRF improves only Constant-Murley scores (MD = 3.93, 95% CI 1.50-6.36, p = .002). However, these differences were small and below the minimum clinically important difference threshold.

CONCLUSIONS

This study showed that compared to arthroscopic rotator cuff repair alone, the application of PRP in arthroscopic rotator cuff repair reduces retear rate and improves clinical function scores, whereas the application of PRF has no clinically meaningful benefit. The small number and heterogeneity of studies as well as methodological limitations and risk of bias limit confidence in the true effect.

A Bibliometric Analysis of Platelet Derivate Uses in Oral and Maxillofacial Surgery

PURPOSE

Concentrated platelet derivatives (PDs) such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) have been extensively applied in tissue engineering, and particularly in various fields of regenerative dentistry. The purpose of the present citation analysis was to compile the 100 top-cited articles on the PDs uses in oral and maxillofacial surgery.

METHODS

A cross-sectional search of the relevant studies in the Web of Science citation database was conducted to identify the 100 most-cited articles. All the included papers consisted of independent variables of this analysis. Covariates that were further considered were basic bibliometric indexes, such as publication year, publishing journal, authorship, institution and country of origin, study design, and field of study. The primary outcome variables were citation counts and citation density. A descriptive analysis of secondary outcome variables, namely bibliographic data such as keyword, abstract, title term co-occurrence analysis, thematic map and wordcloud analysis, was performed using the bibliometrix R and VOSviewer software.

RESULTS

The total citation count for the 100 most-cited articles ranged from 85 to 1821, with 2002 being the most productive year. With 15 articles, the Journal of Periodontology was the most represented journal, followed closely by the Journal of Oral and Maxillofacial Surgery and Clinical Oral Implants Research. The United States published the largest number of papers. Original basic science research studies on implantology and biology dominated the top-cited list. Randomized clinical trials and systematic reviews were adequately represented in the top-cited list. Platelet-derived growth factor and osteoprotegerin represented emerging minimally developed themes, while PRP, growth factors and fibrin, along with the applications of PRF in gingival recession and intra bony defects, were considered important motor themes.

CONCLUSIONS

The current study provides a complete list and in-depth analysis of the 100 most-cited publications relevant to PDs use in oral and maxillofacial surgery, identifying the most important research topics, most impactful authors, institutions, and countries. Though PRP studies were leading the top-cited list, publications focusing on PRF pesented higher citation density values, indicating a continuously increasing citation rate.