The use of autologous platelet-leukocyte gels to enhance the healing process in surgery, a review

Clinical Effects of Additional Platelet-Rich Plasma Application to Exercise Therapy in Patients with Subacromial Impingement Syndrome: A Double-Blind Randomized Controlled Trial

Background

Exercise therapy (ET) is the main and initial treatment modality for treating subacromial impingement syndrome (SIS). The isolated or combined use of platelet-rich plasma (PRP) applications in treating SIS is increasing and promising. A comparison was made on the effectiveness of ET alone and in combination with PRP on pain, functionality, and quality of life (QoL) in patients with SIS.

Purposes/Hypothesis

The purposes of this study were to (1) investigate the possible positive effects of PRP injections combined with ET in treating SIS on pain, functionality, and QoL and (2) propose an alternative treatment protocol. It was hypothesized that the group receiving PRP applications in addition to ET would have a better QoL due to less pain and higher functionality 6 months after treatment.

Study Design

Randomized controlled trial; Level of evidence, 2.

Methods

Volunteer patients diagnosed with SIS were included based on history and physical examination findings. All participants underwent magnetic resonance imaging to confirm the diagnosis and exclude possible accompanying pathologies. The patients were randomly divided into 2 groups. The first group underwent ET at home for 8 weeks (ET group), and the second group received the same ET program and an additional 2 PRP injections, at the beginning of the study and the end of the fourth week (PRP group). Patients were evaluated initially and 6 months after the treatment using the visual analog scale (VAS) for pain score, Constant-Murley Score (CMS), and the 36-Item Short Form Health Survey (SF-36). The Kolmogorov-Smirnov test determined the conformity of the data to a normal distribution, chi-square analysis was used to compare categorical variables between groups, and the Mann-Whitney U test was used to compare continuous and intergroup variables. Intragroup changes before and after treatment were evaluated with the Wilcoxon signed-rank test. P < .05 was considered statistically significant.

Results

A total of 67 patients were initially enrolled; 5 were excluded and 6 were lost to follow-up (1 because of a COVID diagnosis). Thus, 56 patients (56 shoulders) were included for analysis. There were 28 patients in the ET group and 28 patients in the PRP group. There were no statistical differences between groups regarding participant characteristics and clinical evaluations before treatment. A statistically significant improvement was observed in pain (VAS subgroups), functionality (CMS subgroups), and QoL (SF-36 subgroups) evaluations of patients in both the ET and the PRP groups compared with before the treatment and 6 months after treatment (P < .05). At the 6-month posttreatment evaluation, the PRP group was statistically significantly superior to isolated ET in terms of VAS rest (P = .001) and night (P = .004) scores. This superiority was also in favor of the PRP group in flexion strength (P = .001), abduction strength (P = .046), and abduction degree (P = .041) measurements. There was no significant difference between ET and PRP groups regarding VAS activity, CMS, and SF-36 scores (P > .05) at 6 months.

Conclusion

Our study showed that both isolated ET and additional PRP application to ET are effective methods in SIS treatment regarding pain, function, and QoL. Combining ET with PRP was superior in reducing pain and improving abduction degree and strength.

Comparison of efficacy of ultrasound-guided platelet rich plasma injection versus dry needling in lateral epicondylitis-a randomised controlled trial

PURPOSE

To assess whether Ultrasound guided dry needling is adequate for both common extensor tendon tears and tendinosis or whether ultrasound guided platelet rich plasma (PRP) has a superior outcome when compared to dry needling when there are tears of the common extensor tendon.

MATERIALS AND METHODS

This is a single-centre, single-blinded, randomised controlled trial conducted between November 2018 and April 2020. 40 patients diagnosed with lateral epicondylitis based on clinical and sonographic features and having comparable baseline characteristics were randomly assigned to the two study groups (dry needling and PRP). Inclusion criteria were patients aged 20 years or more who were symptomatic for at least 3 months with sonographic evidence of lateral epicondylitis. Exclusion criteria were complete tear of common extensor tendon confirmed on ultrasound and presence of other associated diseases like osteoarthritis of shoulder and elbow.

RESULTS

There was significant improvement in the visual analogue scale pain score in PRP group compared to the dry needling group at 9 months. However, this difference was not evident at 3 and 6 months follow-up. Mean improvement in common extensor tendon thickness in PRP group (5.1 mm at 3 months and 4.3 mm at 6 months) was slightly better than dry needling (4.4 mm at 3 months and 4.0 mm at 6 months). There was no difference in tear (if present) healing between both groups at 3 months. However at 6 months follow up, PRP demonstrated significant (mean-2.5) healing in tear compared to dry needling (mean-3.1).

CONCLUSION

Two injections of Ultrasound guided PRP are more beneficial non operative treatment compared to ultrasound guided dry needling, in lateral epicondylitis.

Standardization and validation of a conventional high yield platelet-rich plasma preparation protocol

BACKGROUND

Of late, numerous randomised controlled trials report platelet-rich plasma (PRP) to be ineffective with preparation protocols of low platelet yield despite using expensive commercial PRP kits.

OBJECTIVE

This study aims to identify and standardize a preparation protocol for PRP with maximum platelets yield and concentration to obtain favourable results without the use of commercial preparation kits.

MATERIALS & METHODS

Blood samples were collected from 40 healthy volunteers who signed informed consent for participation in the study. The double spin protocol of PRP preparation was analyzed for variables such as centrifugal acceleration, time, and volume of blood processed and final product utilized. The final PRP prepared was investigated for platelet recovery, concentration, integrity, and viability. Each protocol investigated with technical and biological duplicates to avoid reporting and sampling bias.

RESULTS

We noted maximum platelet recovery (86-99%) with a consistent 6.4 ± 0.8 times the baseline concentration of platelets with first centrifugation at 100g for 15 min followed by second centrifugation at 1600g for 20 min. We did not note a loss of integrity or viability of the platelets in the final product from the above-said protocol. We also validated the protocol among all the study participants demonstrating consistency.

CONCLUSION

The preparation of PRP by the double-spin protocol using 10 ml of blood at 100 g followed by 1600 g for 15 and 20 min respectively in a 15 ml tube and using the lower 1/3rd of the final product demonstrated consistent high platelet recovery (86-99%) and concentration (6x) without disturbing the platelet integrity or viability.

Blood Conservation Techniques and Strategies in Orthopedic Anesthesia Practice

Orthopedic surgery procedures involving joint arthroplasty, complex spine, long bone and pelvis procedure, and trauma and oncological cases can be associated with a high risk of bleeding and need for blood transfusion, making efforts to optimize patient care and reduce blood loss very important. Patient blood management programs incorporate efforts to optimize preoperative anemia, develop transfusion protocols and restrictive hemoglobin triggers, advance surgical and anesthesia practice, and use antifibrinolytic therapies. Perioperative management of anticoagulant therapies, a multidisciplinary decision-making task, weighs in risks and benefits of thromboembolic risk and surgical bleeding and is patient- and surgery-specific.

Leukocyte-Rich Platelet-Rich Plasma Has Better Stimulating Effects on Tenocyte Proliferation Compared With Leukocyte-Poor Platelet-Rich Plasma

Background:

Rotator cuff (RC) tendinopathy is one of the most common causes of shoulder pain. Platelet-rich plasma (PRP) has been frequently used in clinical scenarios, but its efficacy remains inconsistent.

Purpose:

To investigate the different responses of human tenocytes from torn RCs to leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) in a 2-chamber coculture device.

Study Design:

Controlled laboratory study.

Methods:

PRP was prepared using different platelet and leukocyte concentrations according to 5 groups: (1) LR-PRP with 5000 platelets/µL, (2) LR-PRP with 10,000 platelets/µL, (3) LP-PRP with 5000 platelets/µL, (4) LP-PRP with 10,000 platelets/µL, and (5) control with only culture medium supplementation and without PRP stimulation. Platelet-derived growth factor–AB (PDGF-AB) and transforming growth factor–β1 (TGF-β1) were measured in LR-PRP and LP-PRP via enzyme-linked immunosorbent assay. Microscopy, water-soluble tetrazolium salt assay, and quantitative real-time polymerase chain reaction were used to investigate the morphology, proliferation, and gene expression of RC tenocytes exposed to different PRP formulations. Data were collected from at least 3 independent measurements. The results were analyzed via 1-way analysis of variance, followed by the post hoc Bonferroni test.

Results:

The ratio of leukocytes to 5000 platelets/µL was 29.5 times higher in LR-PRP than in LP-PRP (P < .05). In the 5000 platelets/µL groups, the levels of TGF-β1 and PDGF-AB were both significantly higher in LR-PRP versus LP-PRP (TGF-β1: 367.0 ± 16.5 vs 308.6 ± 30.3 pg/mL, respectively [P = .043]; PDGF-AB: 172.1 ± 1.8 vs 94.1 ± 4.2 pg/mL, respectively [P < .001]). Compared with the control group, RC tenocyte proliferation was 1.42 ± 0.01 and 1.41 ± 0.03 times higher in the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL, respectively (P < .05). The expression of tenocyte-related genes was higher in tenocytes cultured in LR-PRP.

Conclusion:

Both the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL induced more growth factor release and increased RC tenocyte proliferation than did the LP-PRP groups.

Clinical Relevance:

In RC repair, LR-PRP may be better than LP-PRP for increasing the proliferation of tenocytes.

Structure, Barrier Function, and Bioactivity of Platelet-Rich Fibrin Following Thermal Processing

Platelet-rich fibrin (PRF) has been utilized as a substitute for resorbable membranes during guided bone regeneration therapy as it is a more bioactive biomaterial with living cells and growth factors than resorbable membranes. Nevertheless, PRF poses obvious disadvantages in its mechanical strength since its rapid degradability has been shown to typically resorb within a 2-week time period. In the present study, the barrier function and biological and mechanical properties of PRF were investigated both as standard therapy and after thermal processing. Two heating processes were applied: both single-side heating and double-side heating at 90°C for 10 s using a metal plate heater. The appearance and weight of PRF membranes were documented after heating, along with their morphological and mechanical properties evaluated by scanning electron microscope and tensile strength tests. The viability of cells found within PRF membranes was also evaluated using live/dead cell viability and CCK-8 (cell counting kit-8) assays. To comprehensively evaluate the barrier function of PRF membranes, Hoechst staining of human gingival fibroblasts, which can be distinguished from cells within the PRF membrane by emitting blue light at an excitation wavelength of 488 nm, was seeded onto the surface of PRF membranes. Furthermore, osteoblasts were cultured with extracts from different PRF groups to evaluate the biocompatibility of PRF membranes. The degradation rate of PRF membranes was examined by digestion assay. Compared with the nonheated PRF control, the size and weight of PRF membranes led to a significant decrease with a denser PRF microstructure following heating. In summary, the double-sided heating of PRF membranes not only demonstrated an improvement in mechanical and degradation properties but also led to a decrease in cell viability and proliferation.

The Use of Biologics for Hip Preservation

PURPOSE OF REVIEW

A wide array of nonoperative modalities to treat hip pain are aimed at restoring and maintaining the structural and physiologic characteristics of the joint. The purpose of this review is to describe the current understanding of biologics in hip pathology by providing an evidence-based overview of treatment modalities available for orthopedic surgeons.

RECENT FINDINGS

The use of biologics as a primary treatment or adjunct to traditional management has shown encouraging results for the treatment of hip pain. Studies have demonstrated safety with minimal complications when using platelet rich plasma, hyaluronic acid, or stem cells to treat hip pain caused by osteoarthritis, femoroacetabular impingement syndrome, tendinopathy, or osteonecrosis of the femoral head. Several studies have been able to demonstrate meaningful clinical results that can improve treatment standards for hip pain; however, more work must be performed to better delineate the appropriate protocols, indications, and limitations of each modality. Recent advances have inspired renewed interest in biologics for patients with hip pain. We present a concise review of platelet rich plasma, hyaluronic acid, stem cells, and matrix metalloprotease inhibitors and their applicability to hip preservation surgery.

Evidence-Based Clinical Efficacy of Leukocyte and Platelet-Rich Fibrin in Maxillary Sinus Floor Lift, Graft and Surgical Augmentation Procedures

Bone augmentation techniques have increasingly been indicated for re-creating adequate bone height and volume suitable for dental implant sites. This is particularly applicable in the severely atrophic posterior maxilla where sinus perforation (ruptured Schneiderian membrane) is a very common complication and sinus floor elevation or lift is frequently considered a standard procedure. The augmentation of the maxillary sinus can be performed with or without grafting biomaterials. Herein, numerous biomaterials and bone substitutes have been proposed, primarily to sustain the lifted space. In addition, cytokines and growth factors have been used to stimulate angiogenesis, enhance bone formation as well as improve healing and recovery period, either as the sole filling material or in combination with bone substitute materials. Within such, is the family of autologous blood extracts, so-called platelet concentrates, which are simply the "product" resulting from the simple centrifugation of collected whole blood samples of the patient, immediately pre-surgery. Platelet-Rich Fibrin (PRF), a sub-family of platelet concentrates, is a three-dimensional (3-D) autogenous biomaterial obtained, without including anti-coagulants, bovine thrombin, additives, or any gelifying agents during the centrifugation process. Today, it is safe to say that, in implant dentistry and oral and maxillofacial surgery, PRFs (particularly, the pure platelet-rich fibrin or P-PRF and leukocyte and platelet-rich fibrin or L-PRF sub-classes) are receiving the most attention, essentially due to their simplicity, rapidness, user-friendliness/malleability, and cost-effectiveness. Whether used as the sole "bioactive" filling/additive material or combined with bone substitutes, the revolutionary second-generation PRFs have been very often associated with promising clinical results. Hence, this review aims to provide a 10-years update on the clinical effectiveness of L-PRF when applied/used as the "sole" biomaterial in maxillary sinus augmentation procedures. An electronic search using specific keywords for L-PRF and maxillary sinus augmentation was conducted in three main databases (PubMed-MEDLINE database, Google Scholar and Cochrane library) for the period between January 2009-February 2020. The quest yielded a total of 468 articles. Based on the pre-established strict inclusion/exclusion criteria, only seven articles were deemed eligible and included in the analysis. Surprisingly, of the 5 studies which used de-proteinized bovine bone mineral (DBBM) in combination with L-PRF, 60% acclaimed no significant effects and only 40% declared positive effects. Of the two articles which had used allogenous bone graft, 50% declared no significant effects and 50% acclaimed positive effects. Only one study had used L-PRF as the sole grafting material and reported a positive effect. Likewise, positive effects were reported in one other study using L-PRF in combination with a collagen membrane. Due to the heterogeneity of the included studies, this review is limited by the inability to perform a proper systematic meta-analysis. Overall, most of the published studies reported impressive results of L-PRF application as a grafting material (sole or adjuvant) in maxillary sinus augmentation and dental implant restorative procedures. Yet, distinct technical processing for L-PRF preparation was noted. Hence, studies should be approached with caution. Here in, in sinus lift and treatment of Schneider membrane, the formation of mature bone remains inconclusive. More studies are eagerly awaited in order to prove the beneficial or detrimental effects of PRFs, in general and L-PRFs, in specific; especially in their tissue regenerative potential pertaining to the promotion of angiogenesis, enhancing of cell proliferation, stimulation of cell migration and autocrine/paracrine secretion of growth factors, as well as to reach a consensus or a conclusive and distinct determination of the effect of leukocytes (and their inclusion) on inflammation or edema and pain; a call for standardization in PRFs and L-PRFs composition reporting and regimenting the preparation protocols.

Strategies to use fibrinogen as bioink for 3D bioprinting fibrin-based soft and hard tissues

Fibrin gel has been widely used for engineering various types of tissues due to its biocompatible nature, biodegradability, and tunable mechanical and nanofibrous structural properties. Despite their promising regenerative capacity and extensive biocompatibility with various tissue types, fibrin-based biomaterials are often notoriously known as burdensome candidates for 3D biofabrication and bioprinting. The high viscosity of fibrin (crosslinked form) hinders proper ink extrusion, and its pre-polymer form, fibrinogen, is not capable of maintaining shape fidelity. To overcome these limitations and empower fibrinogen-based bioinks for fibrin biomimetics and regenerative applications, different strategies can be practiced. The aim of this review is to report the strategies that bring fabrication compatibility to these bioinks through mixing fibrinogen with printable biomaterials, using supporting bath supplemented with crosslinking agents, and crosslinking fibrin in situ. Moreover, the review discusses some of the recent advances in 3D bioprinting of biomimetic soft and hard tissues using fibrinogen-based bioinks, and highlights the impacts of these strategies on fibrin properties, its bioactivity, and the functionality of the consequent biomimetic tissue. Statement of Significance Due to its biocompatible nature, biodegradability, and tunable mechanical and nanofibrous structural properties, fibrin gel has been widely employed in tissue engineering and more recently, used as in 3D bioprinting. The fibrinogen's poor printable properties make it difficult to maintain the 3D shape of bioprinted constructs. Our work describes the strategies employed in tissue engineering to allow the 3D bioprinting of fibrinogen-based bioinks, such as the combination of fibrinogen with printable biomaterials, the in situ fibrin crosslinking, and the use of supporting bath supplemented with crosslinking agents. Further, this review discuss the application of 3D bioprinting technology to biofabricate fibrin-based soft and hard tissues for biomedical applications, and discuss current limitations and future of such in vitro models.

Hyaluronic acid and fibrin from L-PRP form semi-IPNs with tunable properties suitable for use in regenerative medicine

Autologous leukocyte- and platelet-rich plasma (L-PRP) combined with hyaluronic acid (HA) has been widely used in local applications for cartilage and bone regeneration. The association between L-PRP and HA confers structural and rheological changes that differ among individual biomaterials but has not been investigated. Therefore, the standardization and characterization of L-PRP-HA are important to consider when comparing performance results to improve future clinical applications. To this end, we prepared semi-interpenetrating polymer networks (semi-IPNs) of L-PRP and HA and characterized their polymerization kinetics, morphology, swelling ratio, stability and rheological behavior, which we found to be tunable according to the HA molar mass (MM). Mesenchymal stem cells derived from human adipose tissue (h-AdMSCs) seeded in the semi-IPNs had superior viability and chondrogenesis and osteogenesis capabilities compared to the viability and capabilities of fibrin. We have demonstrated that the preparation of the semi-IPNs under controlled mixing ensured the formation of cell-friendly hydrogels rich in soluble factors and with tunable properties according to the HA MM, rendering them suitable for clinical applications in regenerative medicine.

Wound Healing: In Vitro and In Vivo Evaluation of a Bio-Functionalized Scaffold Based on Hyaluronic Acid and Platelet-Rich Plasma in Chronic Ulcers

Chronic ulcers are characterized by loss of substance without a normal tendency towards spontaneous healing. The Wound Bed Preparation Guideline advises that after diagnosis, the expert should correct the biological state of the ulcer micro-environment based on TIME principles (Tissue, Infection, Moisture balance, Epidermal). There are many ways to treat such ulcers, for example through use of advanced dressings, negative pressure, surgical toilets, dermal substitutes, autologous skin grafting, and free or local flaps. In vitro and in vivo pre-clinical models hold widely acknowledged potential yet complex limitations. Tissue bioengineering could be an ideal approach to foster innovative strategies in wound healing. Our observational study reports on an in vitro and in vivo evaluation of a bio-functionalized scaffold composed of platelet-rich plasma (PRP) and hyaluronic acid (HA) used in 182 patients affected by chronic ulcers (diabetic and vascular), comparing the results with a control group of 182 patients treated with traditional dressings (HA alone). After 30 days the patients who had undergone the combined treatment (PRP + HA), showed 96.8% ± 1.5% re-epithelialization, as compared to 78.4% ± 4.4% in the control group (HA only). Within 80 days, they had 98.4% ± 1.3% re-epithelialization as compared to 87.8% ± 4.1% in the control group (HA only; p < 0.05). No local recurrence was observed during the follow-up period. PRP + HA treatment showed stronger regenerative potential in terms of epidermal proliferation and dermal renewal compared with HA alone.

Changes on the Structural Architecture and Growth Factor Release, and Degradation in Equine Platelet-Rich Fibrin Clots Cultured Over Time

The aims of the present study were (1) to describe the microscopic and ultrastructural appearance of equine platelet-rich fibrin (PRF) clots and (2) to determine the release and degradation of transforming growth factor beta 1 (TGF-β₁) and insulin-like growth factor type I (IGF-I) from PRF clots incubated over 14 days. Whole blood from six horses was collected into plain tubes and centrifuged at 240 g for 8 minutes. Clots were evaluated by histology and by both transmission and scanning electronic microscopy (TEM and SEM). Growth factor concentrations were measured by ELISA at 48-hour intervals over 14 days and analyzed by one-way repeated-measures ANOVA. Histology showed a clot composed by a fibrin layer and a cellular layer with platelets and leukocytes. Scanning electron microscopy showed the cells trapped by an incipient fibrin network at 1 hour. At day 8, these cells were embedded by an incipient fibrin network. At day 14, the leukocytes and platelet aggregates from the clot were imbibed in an organized web of fibrin fibrils. TEM exhibited platelets with preserved cytoplasm and alpha granules randomly scattered at day 8, and damaged platelets with interrupted cytoplasm and organelle emigration to the periphery at day 14. TGF-β₁ and IGF-I concentrations showed a progressive increase until day 14. TGF-β₁ was released from PRF clots in a gradual and controlled manner, and increasing its concentration for two weeks, which supports TEM findings indicating that platelets began disintegrating by day 14. Furthermore, IGF-I production and release from PRF clots is sustained over time.

Effect of the platelet-rich plasma covering of polypropylene mesh on oxidative stress, inflammation, and adhesions

INTRODUCTION AND HYPOTHESIS

Polypropylene mesh (PPM) is often used for urogynecological repair; however, it can cause complications. An approach to reduce complications is to coat PPM with anti-inflammatory and wound-healing molecules. Platelet-rich plasma (PRP) is inexpensive and improves wound healing. Therefore, we evaluated whether covering PPM with PRP could reduce inflammation, adhesion, and oxidative stress (OS) in rabbits.

METHODS

The primary objective was to evaluate OS, and the secondary objectives were to evaluate inflammation and adhesion. PRP-coated PPM was implanted on the right side of the abdominal cavity of 12 female New Zealand rabbits, in the interface between the hypodermis and peritoneum. An uncoverated PPM was implanted in the other side. Twelve rabbits served as the sham group; all animals were euthanized after 30 or 60 days. Inflammatory parameters were myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) activities. OS was evaluated by measuring the ferric-reducing antioxidant power, the free-radical-reducing ability of 3-ethylbenzothiazoline-6-sulfonic acid [2,2'-azino-bis (ABTS)], reduced glutathione levels, and superoxide anion production. Adhesion was measured using tenacity and Diamond scales (the latter of which grades adhesions according to their extent) Inflammation and OS were analyzed by analysis of variance (ANOVA), followed by Tukey's test. The Mann-Whitney test was used to evaluate adhesions, and analysis of the sham group was conducted using Kruskal-Wallis test.

RESULTS

No significant differences were observed in parameters of adhesions. After 60 days, PRP-coverated PPM presented a decrease in MPO and NAG activities. Furthermore, decreased OS and increased antioxidant levels were observed in PRP-coverated PPM samples.

CONCLUSIONS

The reduction of OS and inflammatory responses indicates that PRP-covered PPM is a promising therapeutic approach.

Self-Renewal and Differentiation of Adipose-Derived Stem Cells (ADSCs) Stimulated by Multi-Axial Tensile Strain in a Pneumatic Microdevice

Adipose-derived stem cells (ADSCs) were suggested for treating degenerative osteoarthritis, suppressing inflammatory responses, and repairing damaged soft tissues. Moreover, the ADSCs have the potential to undergo self-renewal and differentiate into bone, tendon, cartilage, and ligament. Recently, investigation of the self-renewal and differentiation of the ADSCs has become an attractive area. In this work, a pneumatic microdevice has been developed to study the gene expression of the ADSCs after the stimulation of multi-axial tensile strain. The ADSCs were cultured on the microdevice and experienced multi-axial tensile strain during a three-day culture course. Self-renewal and differentiation abilities were investigated by mRNA expressions of NANOG, sex determining region Y-box 2 (SOX2), octamer-binding transcription factor 4 (OCT4), sex determining region Y-box9 (SOX9), peroxisome proliferator-activated receptor gamma (PPAR-γ), and runt-related transcription factor 2 (RUNX2). The result showed that the genes related self-renewal were significantly up-regulated after the tensile stimulation. Higher proliferation ratio of the ADSCs was also shown by cell viability assay. The microdevice provides a promising platform for cell-based study under mechanical tensile stimulation.

Use of platelet-rich plasma to facilitate wound healing

Platelet-rich plasma (PRP) is widely used nowadays in different fields of medicine, affecting physiological processes including tissue regeneration. The use of PRP in maxillofacial surgical interventions and its efficiency in the improvement of postoperative wound healing were analysed. Patients undergoing plastic and reconstructive surgeries in the maxillofacial region were recruited: 50 patients were enrolled into a control group (received no PPRP injection) and 50 patients were enrolled into a treatment group, where PRP was applied during the surgical procedure. Evaluation of treatment outcomes was carried out by determination of IL-1β, TNFα, and IL-6 cytokines levels in the wound-drain fluid. The stages of wound healing were assessed by cytological analyses and ultrasound within a month period. The use of the PRP has substantially positive effects, contributing to the improvement of the healing process. In the treatment group, fibroblasts, macrophages, and collagen fibres appeared and their quantities increased earlier than when compared with control group patients. The concentration of IL-1β and TNFα in wound fluid on day 1 and day 5 after operation was higher for the treatment group as opposed to the control group, which was linked to the influence of PRP on inflammatory and granulation phases of the healing process. An ultrasound examination showed less oedema and infiltration in the tissues around the wound of the treatment group.

Investigation of Growth Factor and Tenocyte Proliferation Induced by Platelet Rich Plasma (PRP) in a 3-Chamber Co-Culture Device

The platelet-rich plasma (PRP) has become an attractive topic for soft tissue healing therapy recently. While some clinical reports revealed the effective treatments for knee osteoarthritis, lateral epicondylitis, and rotator cuff tears, other case studies showed that there was no statistically significant healing improvement. The efficacy of the PRP therapy is still unclear clinically. Thus, a significant amount of basic studies should be conducted to optimize the preparation procedure and the platelet concentration of the PRP. In this work, a 3-chamber co-culture device was developed for the PRP study in order to reduce the usage of primary cells and to avoid the PRP gelation effect. The device was a culture, well partitioning into 3 sub-chambers. Tenocytes and PRP could be respectively loaded into the sub-chambers and co-cultured under the interlinked medium. The results showed that a higher platelet number in the PRP could diffuse higher concentration of the growth factors in the medium and induce higher tenocyte proliferation. The 3-chamber co-culture device provides a simple and practical tool for the PRP study. It is potentially applied for optimizing the preparation procedure and platelet concentration of the PRP therapy.

Development of a co-culture device for the study of human tenocytes in response to the combined stimulation of electric field and platelet rich plasma (PRP)

One of the objectives of rotator cuff repairs is to achieve biological healing and recovery in the tendon-bone zone. Some clinical evaluations reported the feasibility of tendon healing based on the stimulations of electric field and platelet-rich plasma (PRP). However, because of lack of appropriate tool for in vitro primary culture under complicated conditions, the efficacy and standard protocol of these healing approaches are still controversial among clinical experts. In this study, a novel co-culture device was developed for the study of tenocytes proliferation under single and combined stimulations of electric field and PRP. The device was a culture well divided into three sub-chambers separated by a barrier and embedded with a pair of parallel plate electrodes. Tenocytes and PRP gel could be respectively loaded into the sub-chambers and cultured with interlinked medium. Hence, tenocytes could concurrently receive a uniform electric field and platelet-derived growth factors by diffusion. Results revealed that the proliferation of tenocytes could be significantly enhanced by these stimulations. The device provides a precise and practical approach for the in vitro study of tendon healing, especially for PRP study. Moreover, optimization of the conditions of electric field and PRP could be determined by in vitro screening procedure before surgery to provide a personalized therapy.

Histological response to platelet-rich plasma added to polypropylene mesh implemented in rabbits

Introduction:

The platelet-rich plasma (PRP) is part of a set of biotechnologies, providing some growth factors that promote repair of different tissues. The polypropylene meshes (PPM) are applied in the correction of abdominal defects, pelvic floor and urinary incontinence, however, they induce many significant complications, as a result of an inappropriate inflammatory response.

Purpose:

To investigate the changes caused by PRP associated with the implantation of PPM in the abdomen of female rabbits, in the production of collagen I and III and the inflammatory infiltrate (ININ).

Materials and Methods:

We performed implant meshes with and without PRP in adult rabbits (n=30) and euthanasia at 7, 30 and 90 days. Two plates were prepared from each animal and analyzed in five different fields. The ININ was evaluated by quantification of inflammatory cells using hematoxylin-eosin and the collagen by Sirius red method. The results were analyzed applying the Wilcoxon, Kruskal-Wallis, Junckheere and Friedmann tests.

Results:

There was a significant difference in the number of inflammatory cells between the groups with and without PRP (p=0.01) at 90 days. There was increased production of collagen I, III and total with the use of PRP, at seven days.

Conclusion:

The PPM coating with PRP was associated with increased ININ at the implant area, and an increasing trend during the process of tissue repair. The PPM coated with PRP was related to increased concentration of collagen I, collagen III and the concentration of total collagen increased after seven days of implantation.

Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma

Background

Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method.

Methods

Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl₂-activated platelet fractions.

Results

The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions.

Conclusions

We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1123-3) contains supplementary material, which is available to authorized users.

Effects of platelet rich plasma on fascial healing in rats with fecal peritonitis

PURPOSE

To evaluate the effects of platelet rich plasma (PRP) on the healing of fascia wherein peritonitis has been created.

METHODS

Twenty eight Wistar Albino rats were divided into four groups. Only a primary fascial repair following laparotomy was performed on Group 1, a primary fascial repair performed and PRP treatment applied following laparotomy on Group 2, and a fecal peritonitis created following laparotomy and a primary fascial repair carried out on Group 3. A fecal peritonitis was created following laparotomy and primary fascial repair and PRP treatment on the fascia was carried out on Group 4.

RESULTS

TNF-α was found to be significantly lower in the control group (Group 1). It was detected at the highest level in the group in which fecal peritonitis was created and PRP applied (Group 4). TGF-β was determined as being significantly higher only in Group 4. Histopathologically, the differences between the groups in terms of cell infiltration and collagen deposition were not found to be significant.

CONCLUSION

When platelet rich plasma was given histologically and biochemicaly as wound healing parameters cellular infiltration, collagen accumulation, and tissue hydroxyiproline levels were not increased but neovascularization, fibroblast activation and TNF Alfa levels were increased and PRP accelerated wound healing.

Topical use of platelet-rich plasma can improve the clinical outcomes after total knee arthroplasty: A systematic review and meta-analysis of 1316 patients

OBJECTIVE

Platelet-rich plasma (PRP) is extracted by centrifuging whole blood and characterized with a high concentration of platelets. The purpose of this systematic review and meta-analysis of randomized controlled trials (RCTs) and non-RCTs is to evaluate the efficacy and safety of platelet-rich plasma (PRP) versus placebo after total knee arthroplasty (TKA).

METHODS

The Electronic databases of PubMed, Web of Science, Embase and Cochrane Database of Systematic Reviews were searched from inception to November 2016 and any studies involving PRP versus placebo for patients prepared for TKA were selected by two reviewers. The primary endpoint is the range of motion (ROM), which represents the function after TKA. The Western Ontario McMaster Universities Osteoarthritis Index Bellamy (WOMAC), pain at 24 h, 48 h and 7 day are also assessed the effect of PRP on the function and pain after TKA. The complications of infection is also compiled to assess the safety of PRP. Stata 12.0 was used to synthesis the final results.

RESULTS

Eleven clinical trials with 1316 patients are included in the meta-analysis. The pooled results indicate that administration PRP significantly increase ROM on the third day (MD = 4.72, 95% CI 2.74, 6.69; P = 0.000) and 3 month postoperatively (MD = 7.55, 95% CI 5.91, 9.19; P = 0.000). There is no statistical difference between the two groups in terms of WOMAC questionnaire score in 3 months (MD = -4.88, 95% CI -12.12, 2.41; P = 0.190). There were no statistical significance between the two groups in pain intensity at 24 h, 48 h and 7 day. There is no statistically significant difference between the PRP versus placebo in terms of the occurrence of infection (RR = 0.64, 95%CI: 0.19-2.14, P = 0.464).

CONCLUSION

Current meta-analysis indicates that PRP is associated with increasing the ROM after TKA in short term and long term. What's more, PRP can also decrease the WOMAC score and pain intensity without increasing the occurrence of infection.

Platelet-Rich Plasma Increases Growth and Motility of Adipose Tissue-Derived Mesenchymal Stem Cells and Controls Adipocyte Secretory Function

Adipose tissue‐derived mesenchymal stem cells (Ad‐MSC) and platelet derivatives have been used alone or in combination to achieve regeneration of injured tissues. We have tested the effect of platelet‐rich plasma (PRP) on Ad‐MSC and adipocyte function. PRP increased Ad‐MSC viability, proliferation rate and G1‐S cell cycle progression, by at least 7‐, 2‐, and 2.2‐fold, respectively, and reduced caspase 3 cleavage. Higher PRP concentrations or PRPs derived from individuals with higher platelet counts were more effective in increasing Ad‐MSC growth. PRP also accelerated cell migration by at least 1.5‐fold. However, PRP did not significantly affect mature adipocyte viability, differentiation and expression levels of PPAR‐γ and AP‐2 mRNAs, while it increased leptin production by 3.5‐fold. Interestingly, PRP treatment of mature adipocytes also enhanced the release of Interleukin (IL)‐6, IL‐8, IL‐10, Interferon‐γ, and Vascular Endothelial Growth Factor. Thus, data are consistent with a stimulatory effect of platelet derivatives on Ad‐MSC growth and motility. Moreover, PRP did not reduce mature adipocyte survival and increased the release of pro‐angiogenic factors, which may facilitate tissue regeneration processes. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc. J. Cell. Biochem. 116: 2408–2418, 2015. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

A meta-analysis of platelet gel for prevention of sternal wound infections following cardiac surgery

Deep sternal wound infection and bleeding are devastating complications following cardiac surgery, which may be reduced by topical application of autologous platelet gel. Systematic review identified seven comparative studies involving 4,692 patients. Meta-analysis showed significant reductions in all sternal wound infections (odds ratio 3.48 [1.08-11.23], p=0.04) and mediastinitis (odds ratio 2.69 [1.20-6.06], p=0.02) but not bleeding. No adverse events relating to the use of topical platelet-rich plasma were reported. The use of autologous platelet gel in cardiac surgery appears to provide significant reductions in serious sternal wound infections, and its use is unlikely to be associated with significant risk.

Platelet-rich plasma versus open surgical release in chronic tennis elbow: A retrospective comparative study

PURPOSE

To compare short and mid-term results in the treatment of chronic elbow tendinosis with platelet-rich plasma (PRP) or Nirschl surgical technique.

METHOD

A retrospective study was conducted on patients with chronic lateral epicondylitis, treated by Nirschl surgical technique (50 elbows) or PRP (60 elbows). Outcome was evaluated with Visual Analog Score (VAS), Mayo Elbow Scores and grip strength measurements.

RESULTS

VAS and Mayo Elbow Scores of the PRP group had improved as a mean of 83% (p = 0.0001), 74% (p = 0.0001) over baseline and 34.2 pounds gain of grip strength.

CONCLUSION

The PRP seems to be better for pain relief and functionality in the short and mid-term periods.

Crosstalk between platelets and PBMC: New evidence in wound healing

Platelet-derived products have proven useful in accelerating healing processes and tissue regeneration. However, despite their widespread use in clinical practice, the cellular and molecular mechanisms involved have not yet been completely clarified. Recent studies show that interaction between platelet gel (PG) and peripheral blood mononuclear cells (PBMC) can result in activation of PBMC and production of several cytokines involved in wound healing and tissue repair. The aim of our study was to analyze whether crosstalk between platelets and PBMC can influence wound healing by modulating release of VEGF, bFGF and IL-10 by PBMC. Cultures of PBMC alone and co-cultures with autologous PG of 24 healthy volunteers were incubated under normoxia for 24 h. VEGF, bFGF and IL-10 concentration and expression were then analyzed in supernatants by ELISA and by real-time RT-PCR. We observed a down-regulation of VEGF and bFGF release and an up-regulation of IL-10 release in co-cultures of PBMC and PG. Platelets are not only important in the early stages of the healing process (clot formation, direct release of growth factors), but also can influence the whole process of tissue regeneration by modulating synthesis and release of VEGF, bFGF and IL-10 by PBMC. These effects could give platelets a new key role in the control of healing processes and provide insights into the clinical success of platelet-derived products in many medical fields.

The clinical efficacy of using autologous platelet rich plasma in hip arthroplasty: A retrospective comparative study

BACKGROUND

Platelet rich plasma (PRP) is a blood derivative concentrate of platelets, fibrin and growth factors obtained through withdrawal and centrifugation of autologous blood and use for its inherent hemostatic and adhesive properties to promote wound healing. Hip arthroplasty is often associated with significant perioperative complications including blood loss necessitating blood transfusions, which can lead to multiple adverse reactions, infection transmission, and longer hospital stay.

MATERIALS AND METHODS

We conducted this retrospective comparative study to determine whether the use of PRP can reduce the bleeding complications in hip replacement surgeries and therefore decrease analgesic requirements and shorten the hospital stay.

RESULTS

Sixty patients had consecutive hip replacement surgeries. The study group (n=23) received PRP applications while the control group (n=37) were operated without PRP applications. Postoperative drop of hemoglobin, number of red blood cell (RBC) transfusions, analgesic requirements, and duration of hospital stay were recorded. There was no significant difference in the drop of hemoglobin preoperatively and postoperatively comparing study and control groups (P=0.75). There was no difference in transfusion requirements between the two groups (P=0.16) but there was trend toward less transfusion in the PRP-treated group. There were also no statistical differences in analgesic use (P=0.83) and lengths of hospitalization (P=0.68) between the two groups.

CONCLUSION

We concluded that there is no clinical efficacy in using PRP in hip replacement surgeries. We recommend a larger prospective study be conducted to determine its clinical utility as an optimization strategy to improve outcome after hip arthroplasty.

Use of platelet-rich plasma to reinforce the staple line during laparoscopic sleeve gastrectomy: feasibility study and preliminary outcome

AIMS

Reinforcement of the staple line is one of the most debated technical aspects concerning laparoscopic sleeve gastrectomy (LSG). Different buttressing methods have been proposed and demonstrated to be effective in reducing the incidence of staple line bleeding, although data concerning their effort on staple line leakage are not consistent. The aim of this study was to ascertain the technical feasibility and to report the preliminary outcomes of laparoscopic use of platelet-rich plasma (PRP) to reinforce the staple line during sleeve gastrectomy.

PATIENTS AND METHODS

From March 2012 to May 2012, 20 patients were prospectively enrolled (10 females; mean age, 44.6 ± 11 years; mean body mass index, 42.3 ± 5.45 kg/m(2)). Type 2 diabetes mellitus was present in 4 patients, obstructive sleep apnea syndrome in 3, and hypertension in 6. LSG was performed using a 48-French bougie and gold cartridges; reinforcement of the staple lines with buttressed materials or oversewing the suture was performed excluding the last cranial cartridge. PRP was prepared by separating the platelets from autologous blood withdrawn on the same day of surgery, in order to obtain a membrane with cylindrical shape (2×5 cm) formed by fibrin and active platelets. The membrane is introduced through the 10-mm trocar and placed at the upper portion of the staple line. The overall cost for the preparation of PRP is about €15.

RESULTS

No intraoperative complications and conversions have been recorded during the surgical procedures. No deaths occurred. The mean operative time was 85 ± 31 minutes, which was not significantly increased compared with the operative time of the surgeon's overall personal series (750 cases). At 12 months of follow-up the abdominal ultrasound was negative for collections, and upper contrast showed no images indicating gastric leaks. In no case did PRP induce symptoms of rejection, infection, or adverse events.

CONCLUSIONS

The use of PRP during LSG is feasible, does not increase significantly the operative time, does not require any special devices, and is cost effective. A larger cohort of patients is needed to ascertain the potential effectiveness of PRP in the prevention of postoperative staple line complications.

Considerations on the use of platelet-rich plasma, specifically for burn treatment

Platelet-rich plasma (PRP) is a fraction of blood plasma with a platelet concentration above baseline. After activation of the platelets, growth factors are released, which are involved in wound-healing processes. Application of a multitude of growth factors seems to boost the healing process. In this review the authors provide a comprehensive overview of the many different aspects of PRP; this is followed by a short outline of the evidence for a wide range of applications and finally narrowing down to a more in-depth analysis of the literature on the potential use of PRP in burn treatment. The authors performed an extensive search on PRP and the different biological, as well as practical aspects for the different applications. Furthermore, we performed a systematic search on PRP in the treatment of burn wounds. A high variety exists in PRP products, procedures, and content. This makes interpretation and comparison of the evidence difficult. PRP has been reported to have beneficial effects on wound healing in different fields of surgery and in the treatment of acute, chronic, and diabetic wounds. Literature on the use of PRP in burns is scarce. Separate growth factors have shown beneficial results in the treatment of burns. Furthermore, an animal study and several case reports showed improved burn wound-healing time after the application of PRP. A deep dermal burn could benefit from PRP through its hemostatic antimicrobial abilities and the positive effects seen in wound healing. However, burn patients have an altered physiological state and it is unknown how this may affect platelet function and quality. Furthermore, the effect of PRP on scarring has not been evaluated properly. Future research is needed to elucidate the role of PRP in the treatment of burns.

Platelet-rich preparations to improve healing. Part II: platelet activation and enrichment, leukocyte inclusion, and other selection criteria

Multiple platelet-rich preparations have been reported to improve wound and bone healing, such as platelet-rich plasma (PRP) and platelet rich fibrin (PRF). The different methods employed during their preparation are important, as they influence the quality of the product applied to a wound or surgical site. Besides the general protocol for preparing the platelet-rich product (discussed in Part 1 of this review), multiple choices need to be considered during its preparation. For example, activation of the platelets is required for the release and enmeshment of growth factors, but the method of activation may influence the resulting matrix, growth factor availability, and healing. Additionally, some methods enrich leukocytes as well as platelets, but others are designed to be leukocyte-poor. Leukocytes have many important roles in healing and their inclusion in PRP results in increased platelet concentrations. Platelet and growth factor enrichment reported for the different types of platelet-rich preparations are also compared. Generally, TGF-β1 and PDGF levels were higher in preparations that contain leukocytes compared to leukocyte-poor PRP. However, platelet concentration may be the most reliable criterion for comparing different preparations. These and other criteria are described to help guide dental and medical professionals, in large and small practices, in selecting the best procedures for their patients. The healing benefits of platelet-rich preparations along with the low risk and availability of simple preparation procedures should encourage more clinicians to incorporate platelet-rich products in their practice to accelerate healing, reduce adverse events, and improve patient outcomes.

Fibrin network architectures in pure platelet-rich plasma as characterized by fiber radius and correlated with clotting time

Fibrin networks are obtained through activation of platelet-rich plasma (PRP) for use in tissue regeneration. The importance of fibrin networks relies on mediation of release of growth factors, proliferation of tissue cells and rheological properties of the fibrin gels. Activation of PRP usually involves the decomposition of fibrinogen by agonists, in a wide range of concentrations. Therefore fibrin networks with a large structural diversity are formed, making comparative evaluations difficult. In order to standardize the fibrin networks, we used the statistical techniques central composite rotatable design and response-surface analysis, to correlate the radius of the fibers with the ratios between the agonists (autologous serum/calcium chloride) and agonist/PRP. From an individual and interactive analysis of the variables, architectures characterized by thick, medium and thin fibers were delineated on the response-surface. Furthermore, the architectures were correlated with coagulation time. This approach is valuable for standardizing the PRP preparation for clinical applications.

Platelet-Rich Preparations to Improve Healing. Part I: Workable Options for Every Size Practice

Numerous studies have demonstrated that platelet-rich preparations applied to surgical sites, injuries, or wounds are a safe and effective way to promote soft tissue healing and bone growth. Various protocols have been developed for preparing platelet-rich preparations, with subtle but important differences between them. Unfortunately, only a minority of clinicians use platelet-rich preparations, such as platelet-rich plasma and platelet-rich fibrin, in their practice, possibly due to confusion about the different methods and their advantages and disadvantages. Therefore, the different types of preparations are described to help guide the selection of the best method for any size practice. Classic methods generally require large volumes of blood and can be expensive, complicated, and time-intensive. Simpler protocols have been developed recently, which require relatively inexpensive equipment and small blood volumes and, thus, may be more applicable for small clinical practices. Platelet-rich preparations accelerate healing at earlier time points to reduce discomfort and the potential for adverse outcomes, including infection, poor wound closure, and delays in forming strong bone for subsequent procedures (such as implants). However, platelet-rich preparations may also improve long-term outcomes in patients expected to have impaired healing, such as with lifestyle choices (eg, smoking), medications (eg, steroids), diseases (eg, diabetes, osteoporosis, atherosclerosis), and aging, by supplementing the deficient wound environment to restore proper healing. Therefore, both large and small clinical practices would benefit from utilizing platelet-rich preparations to enhance healing in their patients.

Relevant aspects of centrifugation step in the preparation of platelet-rich plasma

Introduction. Platelet-Rich Plasma (PRP) is rich in growth factors, playing important role in tissue healing. The wide variation of reported protocols for preparation of PRP leads to variable compositions, which induce different biological responses and prevent results comparison. This study aims to highlight relevant aspects of the centrifugation step to obtain reproducible results and overall quality. Material and Methods. Samples of blood were collected from 20 healthy donors that have signed free informed consent. Two centrifugation steps (spins) were analyzed for the influence of centrifugal acceleration, time, processed volume, and platelet gradient. The Pure Platelet-Rich Plasma (P-PRP) was characterized as platelet concentration, integrity, and viability (sP-selectin measurement). Results. Lower centrifugal accelerations favour platelet separation. The processing of 3.5 mL of blood at 100 ×g for 10 min (1st spin), 400 ×g for 10 min (2nd spin), withdrawing 2/3 of remnant plasma, promoted high platelet recovery (70–80%) and concentration (5x) maintaining platelet integrity and viability. The recovery of platelets was reduced for a larger WB volume (8.5 mL) processed. Conclusion. Centrifugal acceleration, time, WB processed volume, and minimization of the platelet gradient before sampling are relevant aspects to ensure reproducible compositions within the autologous nature of PRP.

Severe hidradenitis suppurativa treatment using platelet-rich plasma gel and Hyalomatrix

Hidradenitis suppurativa (HS) can be a debilitating chronic disease. The underlying cause of the disease is still not clear. HS may be managed through numerous different medical or surgical procedures. Surgical treatment may consist of local excisions and reconstruction using a variety of methods: perforator flaps, skin grafts, local flaps, primary closure or secondary wound healing with vacuum and other devices. This report describes our experience with surgical excision and closure using platelet-rich plasma (PRP) gel and Hyalomatrix PA (HPA) in a patient with severe HS involving most of the body surface. We treated the patient with resection of severe HS of the nuchae and closure with PRP gel prepared with the RegenKit(®) to promote neovascularisation and HPA, a delivery system for hyaluronic acid, to induce a neodermis at the wound bed and to stimulate regeneration in a humid and protected environment. Complete wound healing was achieved after 2 months. The obtained result proved the efficacy of this treatment without complications. No recurrence was observed during the 1 year after the surgical procedure. Severe HS can be safely and effectively managed with wide excision, PRP gel and Hyalomatrix to achieve a successful outcome.

The impact of platelet-rich plasma on the prevention of tunnel widening in anterior cruciate ligament reconstruction using quadrupled autologous hamstring tendon: a randomised clinical trial

The use of platelet-rich plasma (PRP) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery. Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a recognised phenomenon that could compromise revision surgery. The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction.Patients undergoing ACL reconstruction using a hamstring graft were randomly allocated either to have PRP introduced into the tunnels peri-operatively or not. CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured. Patients were also evaluated clinically at three months, when laxity was also measured.Each group comprised 25 patients, and at three months post-operatively all were pain-free with stable knees, a negative Lachman test and a good range of movement. Arthrometric results had improved significantly in both groups (p < 0.001). Despite slightly less tunnel widening in the PRP group, there was no significant difference between the groups at the femoral opening or the mid-tunnel (p = 0.370 and p = 0.363, respectively) nor at the tibial opening or mid-tunnel (p = 0.333 and p = 0.177, respectively).We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction.

Analyzing the effects of platelet gel on knee osteoarthritis in the rat model

Platelet gel (PG) includes concentrated dose of growth factors which plays role in physiological processes of healing. The goal of this study is to evaluate repairing effects of intra-articular injection of PG use in a rat model of knee osteoarthritis (OA). A total of 20 rats were randomly distributed into a PG group and a control group. Both the groups were induced OA in knee joints with intra-articular formaline injection. The rats in the PG group and the control group were injected in the knee joint with PG and 0.9% NaCl solution, respectively. Two weeks after last injections, all rats were sacrificed by ether asphyxiation. Tissue samples were obtained from the knee joints and were examined histopathologically. No statistically significant differences were found between the groups regarding cartilage healing (P > .05). We were unable to determine any beneficial or harmful effects of PG on joint cartilage healing in OA.

No positive bone healing after using platelet rich plasma in a skeletal defect. An observational prospective cohort study

PURPOSE

Platelet rich plasma (PRP) is derived from the patient's own blood. The activated blood platelets release a cocktail of growth factors, some of which are thought to initiate and stimulate repair. We compared two groups to investigate whether the use of PRP mixed with bone chips improves bone healing in patients with a skeletal defect.

METHODS

In total, 41 patients were observed. One group underwent a high tibial osteotomy with the addition of PRP and bone chips in the open wedge. The other group underwent the same procedure without the addition of PRP. Six patients had to be excluded because of insufficient data or they were lost to follow-up. Bone healing was studied using computed tomography scanning. The blood was sequestered and PRP was produced using a blood cell separator with a PRP software program (Electa, Sorin Group, Mirandola, Italy).

RESULTS

Analysis focused on the remaining 35 patients. At baseline, there were no differences between the two groups for age, sex and side of operation. At one week postoperatively, the bone density under (p = 0.02) and above the wedge was significantly lower in the PRP group than the control group (p = 0.24). At six weeks postoperatively, no significant differences between the treatment groups were found. At 12 weeks, the PRP group had significantly lower bone density under the wedge compared to the control group (p = 0.01).

CONCLUSIONS

We found that patients with a skeletal defect did not benefit from the application of PRP mixed with an allograft regarding bone healing.

Regenerative surgery of the complications with Morton's neuroma surgery: use of platelet rich plasma and hyaluronic acid

Morton's neuroma is an entrapment neuropathy of the plantar digital nerve. We treated five patients with wound dehiscence and tendon exposure, after Morton's neuroma surgery excision using a dorsal approach. In this article we describe our technique. From July 2010 to August 2011, at the Department of Plastic and Reconstructive Surgery, University of Rome 'Tor Vergata', five patients (four females and one male), with ages ranging between 35 and 52 years, were treated with a combination of PRP (platelet rich plasma) and HA (hyaluronic acid). Thirty days following surgery, all patients showed a complete healing of the wound. The use of this technique for the treatment of postoperative wound dehiscence and tendon exposure has proven as satisfactory.

Platelet gel in oral and maxillofacial surgery: a single-centre experience

BACKGROUND

Platelet gel is a blood product intended for non-transfusion, therapeutic purposes; it is produced by combining platelet concentrate with cryoprecipitate. Platelet gel stimulates tissue growth and is a key player in tissue regeneration. As an allogeneic product, platelet gel is obtained from the blood of a common type O blood donor, with a platelet count >200×10(3)/μL. Most of the beneficial effects of this product are due to the numerous growth factors (PDGF, TGF-β, IGF-1 and IGF-2, EGF, VEGF and FGF) contained in the alpha-granules of platelets. The aim of this study was to confirm that platelet gel is a valuable aid for the surgical repair of alveolar bone loss.

MATERIALS AND METHODS

Our study was carried out on 87 patients with inflammatory or dysembryoplastic osteolytic lesions >2 cm in diameter in jaw bones. For most patients the platelet gel was collected into a 450 mL bag and kept frozen at -40 °C until, whereas for a small group of patients the gel was prepared and activated in the sterile field of the operating theatre.

RESULTS

All of our patients reported a decrease in painful symptoms immediately after surgery. Follow-up showed considerable acceleration of the healing processes in soft tissues and faster bone regeneration.

CONCLUSION

Multicentre studies are needed in order to standardise the methods for producing platelet gel and the clinical use of this product. Furthermore, for research purposes in vitro studies are needed to increase knowledge on the functional network and platelet growth factors and also to investigate the biochemical and molecular mechanisms involved.

Ongoing positive effect of platelet-rich plasma versus corticosteroid injection in lateral epicondylitis: a double-blind randomized controlled trial with 2-year follow-up

BACKGROUND

Platelet-rich plasma (PRP) has been shown to be a general stimulation for repair and 1-year results showed promising success percentages.

PURPOSE

This trial was undertaken to determine the effectiveness of PRP compared with corticosteroid injections in patients with chronic lateral epicondylitis with a 2-year follow-up.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

The trial was conducted in 2 Dutch teaching hospitals. One hundred patients with chronic lateral epicondylitis were randomly assigned to a leukocyte-enriched PRP group (n = 51) or the corticosteroid group (n = 49). Randomization and allocation to the trial group were carried out by a central computer system. Patients received either a corticosteroid injection or an autologous platelet concentrate injection through a peppering needling technique. The primary analysis included visual analog scale (VAS) pain scores and Disabilities of the Arm, Shoulder and Hand (DASH) outcome scores.

RESULTS

The PRP group was more often successfully treated than the corticosteroid group (P < .0001). Success was defined as a reduction of 25% on VAS or DASH scores without a reintervention after 2 years. When baseline VAS and DASH scores were compared with the scores at 2-year follow-up, both groups significantly improved across time (intention-to-treat principle). However, the DASH scores of the corticosteroid group returned to baseline levels, while those of the PRP group significantly improved (as-treated principle). There were no complications related to the use of PRP.

CONCLUSION

Treatment of patients with chronic lateral epicondylitis with PRP reduces pain and increases function significantly, exceeding the effect of corticosteroid injection even after a follow-up of 2 years. Future decisions for application of PRP for lateral epicondylitis should be confirmed by further follow-up from this trial and should take into account possible costs and harms as well as benefits.

Platelet gel in the treatment of cutaneous ulcers: the experience of the Immunohaematology and Transfusion Centre of Parma

BACKGROUND

Platelet gel is being ever more frequently used to promote healing of cutaneous ulcers. However, the factors that determine the often variable clinical outcome of this procedure are still incompletely understood.

AIMS

The aims of this study were to demonstrate that platelet gel, even when obtained under strictly controlled conditions, produces highly variable outcomes in patients with cutaneous ulcers and to propose a method for in vitro standardisation of the biological properties of platelet gel. MATERIAL AND METHODS.: Patients were enrolled on the basis of a pre-defined protocol. Platelet concentrate was produced with standard methods, with a variability in platelet count among the different samples of less than 10%. The platelet gel for clinical use was obtained, under strictly standardized conditions, by adding thrombin and calcium gluconate to the concentrates. For in vitro studies, platelet gel, obtained from platelet-rich plasma from four donors, was frozen and thawed twice so as to increase gel contraction. The supernatant was used to modify cell proliferation, protein synthesis, and the expression of selected genes in cultures of human diploid fibroblasts.

RESULTS

Seventeen patients (aged 44-78 years) with ulcers (4 diabetic, 11 vascular, 1 post-traumatic, 1 decubitus) were treated with platelet gel (4 autologous, 13 homologous). Complete re-epithelialisation of four ulcers (1 diabetic, 1 post-traumatic, 2 vascular) was obtained after applications of platelet gel (2 autologous, 2 homologous); in 11 other cases there was a greater than 50% reduction in the size of the ulcer. Two patients had no benefit. The supernatant of the platelet gel was able to promote dose-dependent proliferation and changes in gene expression as well as in metabolic activities related to protein synthesis.

CONCLUSIONS

Although the use of platelet gel in the treatment of cutaneous ulcers is increasing, and conditions for its production are better standardised, very considerable variability of clinical outcomes is still observed, even within single centres, suggesting that there are differences in biological properties of platelet concentrates from individual patients which cannot be readily controlled with current techniques. The biological effects of the platelet gel supernatant described in this article may provide the basis for a simple biological validation of platelet preparations before their clinical use, so as to reduce this potentially important source of variability.

Current concepts for the use of platelet-rich plasma in the foot and ankle

Platelet-rich plasma (PRP) injections have been used and studied since the 1970s. Its use has become more popularized over the last several years in the treatment of foot and ankle injuries. Platelets are a normal product found in the clotting cascade and inflammatory process of healing. They produce granules that release growth factors that promote healing. PRP works by increasing the concentration of platelets, thereby increasing the concentration of growth factors and increasing healing potential. PRP has an advantage over many tissue engineering products in that it is autologous. It has been studied and used for the treatment of tendon injuries, chronic wounds, ligamentous injuries, cartilage injuries, muscle injuries, and bone augmentation. The results from in vitro and in vivo studies in foot and ankle injuries are promising. The applications for treatment in the foot and ankle may be broader than once thought.

Autologous platelet gel in total knee arthroplasty: a prospective randomized study

PURPOSE

Total knee arthroplasty (TKA) is often associated with major postoperative blood loss, postoperative pain, and impaired wound healing. The application of autologous platelet gel (APG), prepared from the buffy coat of a unit of autologous blood, has been advocated to improve haemostasis after surgery, to decrease perioperative blood loss, diminish postoperative pain and to enhance the wound healing process. This randomized controlled pilot study was developed to assess the effects of APG after total knee arthroplasty on blood loss, wound healing, pain, range of motion, and hospital stay.

METHOD

A prospective, randomized observer blind controlled trial was performed. Forty patients with only osteoarthritis of the knee were scheduled to have a TKA, and they were randomized into two groups. Patients in the treatment group were all treated with the application of autologous platelet gel after the prosthesis was implanted. Patients in the control group were treated with the same protocol but no APG was used.

RESULTS

Preoperative and postoperative Hb levels showed no significant difference and allogenic blood transfusions were not given in either group. Haematomas were significantly larger in the control group than in the platelet gel group (P = 0.03). The pain score at rest was higher in the control group on the 3rd day (P = 0.04). Wound healing disturbances were seen in four patients in the control group and in no patients in the APG group (n.s.). Range of motion of the knee was similar postoperatively. Hospital stay was 6.2 days in the APG and 7.5 days in the control group (n.s.).

CONCLUSION

In this prospective randomized pilot study on APG in total knee arthroplasty, differences in favour of the use of platelet gel were found, but these were subjective evaluations, marginal in effect, or did not reach statistical significance. The use of drains might have decreased the concentration of delivered platelets and may have diminished the effect. However, in this study, a statistically significant clinically important effect in favour of platelet gel application was not found. Further studies with larger numbers of patients, and without the use of drains, are warranted to investigate the possible benefits of autologous platelet gel in total knee arthroplasty.