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 ß, 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.

Histological effect of platelet-rich plasma on temporomandibular joint osteoarthritis: systematic review in animal models

SUMMARY: The aim of this systematic review was to assess the histological effects of platelet-rich plasma (PRP) on temporomandibular joint osteoarthritis (TMJ-OA) in animal models. A systematic search was performed using PubMed, WoS, EMBASE, Science Direct and SCOPUS databases. The inclusion criteria were experimental studies in animal models that evaluated the use of PRP as a treatment for TMJ-OA with or without arthrocentesis/arthroscopy. Comparison was made to a healthy control group or to other treatment. The variables evaluated were the histological effects of the treatments, characteristics of the primary articles, characteristics of the sample studied and the risk of bias. The systematic search identified 120 studies. Eventually 5 studies were included in the analysis. Four of the studies showed a statistically significant repair in joint tissues and improvement of cartilage thickness in animals treated with PRP. The global risk of bias was unclear. The results of this systematic review suggest that PRP treatment in TMJ-OA has benefits at the histological level in cartilage, articular disc and articular bone tissue in animal models. However, due to the low number of studies and the risk of bias, further research is needed to recommend its use.

El objetivo de esta revisión sistemática fue evaluar los efectos histológicos del plasma rico en plaquetas (PRP) en la osteoartritis de la articulación temporomandibular (ATM-OA) en modelos animales. Se realizó una búsqueda sistemática en las bases de datos PubMed, WoS, EMBASE, Science Direct y SCOPUS. Los criterios de inclusión fueron estudios experimentales en modelos animales que evaluaran el uso de PRP como tratamiento para la ATM-OA con o sin artrocentesis/ artroscopia. La comparación se realizó con un grupo de control sano o con otro tratamiento. Las variables evaluadas fueron los efectos histológicos de los tratamientos, las características de los artículos primarios, las características de la muestra estudiada y el riesgo de sesgo. La búsqueda sistemática identificó 120 estudios. Finalmente se incluyeron 5 estudios en el análisis. Cuatro de los estudios mostraron una reparación estadísticamente significativa en los tejidos articulares y una mejora del grosor del cartílago en los animales tratados con PRP. El riesgo global de sesgo fue incierto. Los resultados de esta revisión sistemática sugieren que el tratamiento con PRP en la ATM-OA tiene beneficios a nivel histológico en el cartílago, el disco articular y el tejido óseo articular en modelos animales. Sin embargo, debido al escaso número de estudios y al riesgo de sesgo, se necesitan investigaciones adicionales para recomendar su uso.

Advances and prospects of platelet-rich plasma therapy in veterinary ophthalmology.

In the recent decades, there has been a significant uptick on the use of platelet-rich plasma (PRP) as a better alternative for ophthalmologic therapies in pathologies, primarily of the ocular surface. PRP is a class of liquid platelet concentrate containing a supra-physiological concentration of platelets in a relatively small amount of plasma. Its potential to heal various tissues has piqued interest in its therapeutic application as a biomaterial in regenerative medicine. It is currently a popular therapeutic agent in plastic surgery, cardiothoracic surgery, reconstructive surgery, and even oral and maxillofacial surgery. Based on the data from in vitro and in vivo studies, it can be concluded that PRP possesses adequate therapeutic potential in ocular pathologies, especially those involving cornea. In addition, the high concentrations of growth factors (TGF-ß, VEGF, EGF) present in the PRP accelerate the healing of the corneal epithelium. PRP has great therapeutic prospects in veterinary ophthalmology as a regenerative therapeutic modality. However, several variables are yet to be defined and standardized that can directly affect the efficacy of PRP application in different ophthalmic conditions. There is a shortage of research on the use of PRP in ocular surface defects compared to the number of studies and reports on the use of autologous and allogeneic serum eye drops. Therefore, a data-driven approach is required to generate consensus/guidelines for the preparation, characterization, and therapeutic use of PRP in veterinary ophthalmology. This review aims to inform readers of the latest research on PRP, including its preparation methods, physiological and biochemical properties, clinical applications in veterinary ophthalmology, and their safety and efficacy.

Lyophilized Platelet-rich plasma for the management of thin endometrium and facilitation of in-vitro fertilization.

OBJECTIVE: Adequate endometrial thickness has been considered an important parameter for hormonal response and blastocyst implantation in assisted reproduction therapies. While there is no consensus on the exact thickness of the endometrium considered 'adequate,' a thin endometrium (<7mm) has been associated with compromised outcomes in assisted reproduction therapies. Platelet-rich plasma (PRP), which is a concentrate obtained from peripheral blood, is a rich source of growth factors that play important roles in various cellular processes. The objective is to utilize lyophilized PRP (LPRP) to increase the thickness of the endometrium and enhance the outcomes of embryo transfer in women with poor response to previous in-vitro fertilization procedures. METHODS: This study enrolled nine women between 23 and 42 years of age, with a thin endometrium, who had undergone multiple previous unsuccessful assisted reproduction procedures. All patients underwent intrauterine infusion of LPRP, followed by frozen-thawed embryo transfer after 2-3 days. RESULTS: Endometrial thickness was assessed by ultrasound 2 weeks after LPRP infusion, which showed improved thickness in all patients (range, 0.7-2.2mm). Clinical pregnancy occurred in all patients and eight out of nine patients are currently between 9 weeks and 27 weeks of gestation. Twin fetal heartbeats were not detected at the eighth week in one patient. CONCLUSION: Infusion of LPRP was found to be beneficial to increase endometrium thickness in all patients. This regenerative technique could be considered to enhance the outcomes of assisted reproduction techniques in a minimally-invasive manner, without any side effects.

Current State of Platelet-Rich Plasma and Cell-Based Therapies for the Treatment of Osteoarthritis and Tendon and Ligament Injuries.

➤: Orthobiologics encompass numerous substances that are naturally found in the human body including platelet-rich plasma (PRP), isolated growth factors, and cell therapy approaches to theoretically optimize and improve the healing of cartilage, fractures, and injured muscles, tendons, and ligaments. ➤: PRP is an autologous derivative of whole blood generated by centrifugation and is perhaps the most widely used orthobiologic treatment modality. Despite a vast amount of literature on its use in osteoarthritis as well as in tendon and ligament pathology, clinical efficacy results remain mixed, partly as a result of insufficient reporting of experimental details or exact compositions of PRP formulations used. ➤: Mesenchymal stromal cells (MSCs) can be isolated from a variety of tissues, with the most common being bone marrow aspirate concentrate. Similar to PRP, clinical results in orthopaedics with MSCs have been highly variable, with the quality and concentration of MSCs being highly contingent on the site of procurement and the techniques of harvesting and preparation. ➤: Advances in novel orthobiologics, therapeutic targets, and customized orthobiologic therapy will undoubtedly continue to burgeon, with some early promising results from studies targeting fibrosis and senescence.

Autologous platelet concentrates in oral surgery: protocols, properties, and clinical applications.

Autologous platelet concentrates (APCs) are a relatively new phenomenon, with initial reports of their regenerative potential published as recently as 1998. Despite their relative infancy, a huge body of evidence exists in support of their capacity to promote osseous and soft tissue regeneration through the physiologic processes of platelet activation and subsequent growth factor release. APCs have transformed many areas of healthcare and are now considered an essential component of the surgical milieu. In this narrative review, we explore the evolution of autologous platelet therapies with a particular emphasis on their contemporary applications in oral surgery, which rather fittingly was the first specialty to report the regenerative potential of APCs.

Platelet HMGB1 in Platelet-Rich Plasma (PRP) promotes tendon wound healing.

Platelet-rich plasma (PRP) is a widely used autologous treatment for tendon injuries in clinics. Platelets (PLTs) are a major source of high mobility group box1 (HMGB1) that is gaining attention as a chemoattractant that can recruit stem cells to the wound area to enhance healing of injured tissues; however, the contribution of PLT HMGB1 in wounded tendon healing remains unexplored. This study investigated the effect of PLT HMGB1 within PRP on tendon healing using PLT HMGB1 knockout (KO) and GFP mice. A window defect was created in the patellar tendons of both groups of mice, and wounds were treated with either saline, PRP isolated from PLT HMGB1-KO mice, or PRP isolated from GFP mice. Seven days post-treatment, animals were sacrificed and analyzed by gross inspection, histology, and immunostaining for characteristic signs of tendon healing and repair. Our results showed that in comparison to mice treated with PRP from PLT HMGB1-KO mice, wounds treated with PRP from GFP mice healed faster and exhibited a better organization in tendon structure. Mice treated with PRP from PLT HMGB1-KO mice produced tendon tissue with large premature wound areas and low cell densities. However, wounds of PLT HMGB1-KO mice showed better healing with PRP from HMGB1-KO mice compared to saline treatment. Moreover, wounds treated with PRP from GFP mice had increased extracellular HMGB1, decreased CD68, increased stem cell markers CD146 and CD73, and increased collagen III protein expression levels compared to those treated with PRP from PLT HMGB1-KO mice. Thus, PLT HMGB1 within PRP plays an important role in tendon wound healing by decreasing inflammation, increasing local HMGB1 levels, and recruiting stem cells to the wound area in the tendon. Our findings also suggest that the efficacy of PRP treatment for tendon injuries in clinics may depend on PLT HMGB1 within PRP preparations.

Platelet-rich fibrin for root coverage: A plausible approach in periodontal plastic and esthetic surgery.

Predictable esthetic root coverage has evolved into conventional treatment modalities making cosmetic procedures an integral part of periodontal treatment. The advent of second-generation platelet concentrates, i.e., platelet-rich fibrin (PRF), has broad clinical application in medical as well as dental field with its recent use for recession defects. The simplicity of PRF procurement and its low cost makes it most suitable for use in daily clinical practice. This particular case report foregrounds the benefit of PRF membrane along with coronally repositioned flap for mucogingival surgery on the labial surface of an upper anterior tooth.

Résumé La couverture radiculaire esthétique prévisible a évolué vers des modalités de traitement conventionnelles faisant des procédures cosmétiques une partie intégrante du parodontal traitement. L'avènement des concentrés plaquettaires de deuxième génération, c'est-à-dire la fibrine riche en plaquettes (PRF), a une large application clinique en médecine comme ainsi que le domaine dentaire avec son utilisation récente pour les défauts de récession. La simplicité de l'approvisionnement en PRF et son faible coût le rendent particulièrement adapté utilisation dans la pratique clinique quotidienne. Ce rapport de cas particulier met en avant les avantages de la membrane PRF avec le volet repositionné coronairement pour chirurgie mucogingivale sur la surface labiale d'une dent antérieure supérieure.

Stromal cell-derived factor (SDF)-1α and platelet-rich plasma enhance bone regeneration and angiogenesis simultaneously in situ in rabbit calvaria.

The current study aimed to evaluate the effects of chemokine stromal cell-derived factor (SDF)-1α and platelet-rich plasma (PRP) on bone formation and angiogenesis, and to assess whether SDF-1α and PRP could function synergistically. Four evenly distributed defects (8 mm in diameter) were generated in the calvarial bones of New Zealand white rabbits. All rabbits received four treatment regimens containing autogenous bone particles (AB), SDF-1α, or PRP. AB group presented significantly less bone formation compared with the other three groups 2 and 4 weeks after surgery. The amount of newly formed bone in the AB+PRP+SDF-1α group was similar to that in the AB + SDF-1α group at the 4-week time-point (p = 0.65), and was much greater than that in the AB and AB+PRP group (p < 0.001). Meanwhile, more new blood vessels were formed in the AB+PRP, AB+SDF-1α, and AB+PRP+SDF-1α group versus the AB group. AB+PRP+SDF-1α group showed statistically increased angiogenesis compared with the AB+PRP and AB+SDF-1α groups (both p < 0.05) after treatment for 2 and 4 weeks. These findings indicated that SDF-1α and PRP might exhibit synergistic effects to promote angiogenesis in early bone regeneration.

Use of Intra-uterine Injection of Platelet-rich Plasma (PRP) for Endometrial Receptivity and Thickness: a Literature Review of the Mechanisms of Action.

Endometrial receptivity and thickness play an important role in achieving a pregnancy. Intrauterine autologous platelet-rich plasma (PRP) infusion has been used in infertile women with recurrent implantation failure (RIF) and thin endometrial lining thickness (EMT). Literature search was performed in PubMed for studies including in vitro, animal, and human studies as well as in abstracts presented at national conferences. Animal studies demonstrated a decrease in the expression of inflammatory markers and fibrosis, and increased endometrial proliferation rate, increased expression of proliferative genes, and increased pregnancy rates. The in vitro studies showed that PRP was associated with increased stromal and mesenchymal cell proliferation, increased expression of regenerative enzymes, and enhancement in cell migration. In infertile women undergoing assisted reproductive technology, one randomized clinical trial showed that PRP intrauterine infusion improved EMT, implantation rate, and clinical pregnancy rate (CPR) in patients with thin EMT, while 3 other trials involving subjects with RIF showed conflicting results related to CPR. Case series and cohort studies showed conflicting results pertaining to CPR. Data to date suggest that PRP may be beneficial in improving endometrial thickness and endometrial receptivity. However, further large prospective and high-quality trials are needed to assert its effect and to identify the population of patients that would benefit the most.

Plasma rico en plaqueta en el tratamiento de la enfermedad degenerativa discal / Platelet-rich plasma in the treatment of degenerative disc disease

Introducción: La enfermedad degenerativa discal es una entidad frecuente y uno de los principales motivos de consulta. Genera altas tasas de discapacidad, años útiles perdidos, así como altos costos económicos por asistencia médica y grandes pérdidas monetarias. Su tratamiento es generalmente conservador, aunque en la actualidad se incluyen terapias biológicas novedosas. Objetivo: Describir las principales propiedades biológicas que hacen del plasma rico en plaquetas una terapéutica efectiva para la enfermedad degenerativa discal. Métodos: Se realizó una revisión no sistemática de la bibliografía basada en artículos que se publicaron en bases de datos indexadas en Infomed como Hinari, Ebsco, Scielo, Pubmed, Cubmed, Cocrhane, Scopus, LILACS; en idioma español, inglés y portugués, durante los últimos diez años. Desarrollo: Se expusieron características clínico epidemiológicas de la enfermedad degenerativa discal, así como las propiedades biológicas que le permiten al plasma rico en plaqueta tener una función activa en la regeneración del disco intervertebral o el retraso de la cascada de degradación de este. Se resaltan los principales estudios de acuerdo a la vía de administración del plasma rico en plaquetas y sus resultados. Conclusiones: De acuerdo con lo publicado por los autores, el plasma rico en plaquetas es una alternativa efectiva en el tratamiento de la enfermedad degenerativa discal por la producción de factores derivados de las plaquetas, que intervienen en la degeneración del disco intervertebral, siendo la vía intradiscal la que más se emplea(AU)

Introduction: Degenerative disc disease is a frequent condition and one of the main reasons to attend the consultation. It generates high rates of disability, useful years lost, as well as high economic costs for medical assistance and large monetary losses. Its treatment is generally conservative, although novel biological therapies are currently included. Objective: To describe the main biological properties that make platelet-rich plasma an effective therapy against degenerative disc disease. Methods: A nonsystematic review of the bibliography was carried out based on articles published, during the last ten years, in databases indexed in Infomed, such as Hinari, Ebsco, Scielo, Pubmed, Cubmed, Cocrhane, Scopus, and LILACS, in Spanish, English and Portuguese. Development: Clinical-epidemiological characteristics of degenerative disc disease were presented, as well as the biological properties that allow platelet-rich plasma to have an active function in the regeneration of the intervertebral disc or the delay of its degradation cascade. The main studies are highlighted, according to the route of administration of platelet-rich plasma and their results. Conclusions: According to what has been published by authors, platelet-rich plasma is an effective alternative in the treatment of degenerative disc disease, due to the production of factors derived from platelets, which intervene in the degeneration of the intervertebral disc, being the intradiscal pathway the most used(AU)

A narrative review of platelet-rich plasma (PRP) in reproductive medicine.

PURPOSE: Platelet-rich plasma (PRP) has become a novel treatment in various aspects of medicine including orthopedics, cardiothoracic surgery, plastic surgery, dermatology, dentistry, and diabetic wound healing. PRP is now starting to become an area of interest in reproductive medicine more specifically focusing on infertility. Poor ovarian reserve, menopause, premature ovarian failure, and thin endometrium have been the main areas of research. The aim of this article is to review the existing literature on the effects of autologous PRP in reproductive medicine providing a summation of the current studies and assessing the need for additional research. METHODS: A literature search is performed using PubMed, MEDLINE, and CINAHL Plus to identify studies focusing on the use of PRP therapy in reproductive medicine. Articles were divided into 3 categories: PRP in thin lining, PRP in poor ovarian reserve, and PRP in recurrent implantation failure. RESULTS: In women with thin endometrium, the literature shows an increase in endometrial thickness and increase in chemical and clinical pregnancy rates following autologous PRP therapy. In women with poor ovarian reserve, autologous intraovarian PRP therapy increased anti-Mullerian hormone (AMH) levels and decreased follicle-stimulating hormone (FSH), with a trend toward increasing clinical and live birth rates. This trend was also noted in women with recurrent implantation failure. CONCLUSIONS: Limited literature shows promise in increasing endometrial thickness, increasing AMH, and decreasing FSH levels, as well as increasing chemical and clinical pregnancy rates. The lack of standardization of PRP preparation along with the lack of large randomized controlled trials needs to be addressed in future studies. Until definitive large RCTs are available, PRP use should be considered experimental.

Anti-inflammatory effect of different PRGF formulations on cutaneous surface.

Cutaneous autoimmune and inflammatory diseases are a major burden of global disease and many lack effective treatments that can derive in different dermatoses like atopic dermatitis. Despite the increase prevalence and the high health-care costs worldwide, the heterogeniety and multifactoriality of these diseases mean that effective treatment options are scarce. Plasma rich in growth factors (PRGF) technology could be an alternative approach that may help in the management of this cutaneous condition. The aim of this study was to assess the effect of two different PRGF formulations (just activated and autologous topical serum (ATS)) for the management of skin inflammation. Additionally, ATS was assessed over two patients suffering from radiotherapy induced dermatitis. Human organotypic skin explant cultures (hOSECs) were used as human skin models. To induce atopic dermatitis-like conditions, skin explants were treated with both interleukin-4 (IL-4) and interleukin-13 (IL-13). PRGF and ATS were intradermally and topically applied, respectively. Metabolic activity, reactive oxigen species (ROS), necrosis and inflammatory cytokine production were determined. Both PRGF formulations increased tissue viability and significantly reduced the excessive free radical accumulation and the cutaneous cytokine production such as TNF-α and IL-1ß. Case reports showed a positive response after ATS treatment in terms of skin quality improvement, local erythema decrease and burning and itching amelioration. The oedema, swelling and desquamation caused by radiation induced dermatitis was also reduced and the patients referred ceased pruritus and pain. This preliminary study suggests that PRGF might aid in the management of inflammatory skin conditions.

Platelet-rich plasma (PRP) in osteoarthritis (OA) knee: Correct dose critical for long term clinical efficacy.

Despite encouraging results reported with regards to Platelet-rich plasma (PRP) application in osteoarthritis (OA) knee, still critical issues like conclusive structural evidence of its efficacy, standard dose and good manual method of preparation to obtain high yield remains unanswered. Present study is an attempt to optimise the dose and concentration of therapeutic PRP and its correlation with structural, physiologic efficacy with a new manual method of PRP preparation. A total of one hundred and fifty patients were randomized to receive either PRP (10 billion platelets) or hyaluronic acid (HA; 4 ml; 75 patients in each group) and followed up till 1 year. An addition of filtration step with 1 µm filter in manual PRP processing improved platelet recovery upto 90%. Significant improvements in WOMAC (51.94 ± 7.35 vs. 57.33 ± 8.92; P < 0.001), IKDC scores (62.8 ± 6.24 vs 52.7 ± 6.39; P < 0.001), 6-min pain free walking distance (+ 120 vs. + 4; P < 0.001) persisted in PRP compared to HA group at 1 year. Significant decline IL-6 and TNF-α levels observed in PRP group (P < 0.05) compared to HA at 1 month. Study demonstrated that an absolute count of 10 billion platelets is crucial in a PRP formulation to have long sustained chondroprotective effect upto one year in moderate knee OA.

Fat grafting and platelet-rich plasma in wound healing: a review of histology from animal studies.

Stem cells could form the basis of a novel, autologous treatment for chronic wounds like diabetic foot ulcers. Fat grafts contain adipose-derived stem cells (ADSC) but low survival of cells within the grafts is a major limitation. Platelet-rich plasma (PRP) may increase graft survival. This review examines the histology from animal studies on fat grafting, ADSC and PRP in wound healing. A literature review of major electronic databases was undertaken, and narrative synthesis performed. Data from 30 animal studies were included. ADSC increase angiogenesis over 14 days and often clinically accelerated wound healing. ADSC had a greater effect in animals with impaired wound healing (e.g. diabetes). Activated PRP increased viability of fat grafts. Despite the high number of studies, the quality is variable which weakens the evidence. It does suggest there is a benefit of ADSC, particularly in impaired wound healing. High-quality evidence in humans is required, to establish its clinical usefulness.

Bilateral Boston keratoprosthesis type 1 in a case of severe Mooren's ulcer.

INTRODUCTION: Mooren's ulcer is a painful, inflammatory chronic keratitis that affects corneal periphery, progressing centripetally, ultimately ending in perforation. The first line of treatment includes systemic immunomodulators, with surgery being the last option. We present a case of bilateral Boston keratoprosthesis implantation for severe Mooren's ulcer that responded differently in each eye. CLINICAL CASE: A 32-year-old male with corneal opacification, anterior staphylomas, vision of hand movement, was started on systemic immunosuppression with cyclosporine. After two failed penetrating keratoplasties in each eye, high intraocular pressure despite diode cyclophotocoagulation, and cystic macular edema, we performed Boston keratoprosthesis type 1 in both eyes. The right eye responded initially well, with a best-corrected visual acuity of 20/80 and normal intraocular pressure. The left eye presented high intraocular pressure, which required cyclophotocoagulation, ultimately resulting in hypotony. Boston keratoprosthesis was performed but had peripheral corneal necrosis that progressed despite amniotic membrane transplantation and aggressive intensive treatment with medroxyprogesterone, autologous platelet-rich-in-growth-factors eye drops, and oral doxycycline. Thus, replacement of the semi-exposed Boston keratoprosthesis with tectonic penetrating keratoplasty was necessary. However, both eyes developed phthisis bulbi with final visual acuity of perception of light with poor localization. CONCLUSION: Mainstay treatment of Mooren's ulcer is systemic immunomodulation. Surgical treatment must be considered only when risk of perforation, preferably with inflammation under control. Penetrating keratoplasty frequently fails, and Boston keratoprosthesis may be a viable option. However, postoperative complications, especially uncontrolled high intraocular pressure, corneal necrosis, and recurrence of Mooren's ulcer may jeopardize the outcomes and need to be addressed promptly with intensive topical and systemic treatment.

Platelet-Rich Plasma: Evolving Role in Plastic Surgery.

BACKGROUND: The use of platelet-rich plasma has emerged as one of the most desired nonsurgical treatments for facial rejuvenation and hair restoration. It has grown to encompass a wide variety of applications within the field of plastic surgery, including its use in combination with microneedling, laser, and fat-grafting procedures. METHODS: In this article, the authors aim to (1) describe the preparation process of platelet-rich plasma; (2) discuss the proposed science behind platelet-rich plasma with regard to its evolving role in hair restoration and facial rejuvenation; and (3) highlight the recent literature examining its widespread use. RESULTS: Based on the available literature, there is a therapeutic advantage to the use of platelet-rich plasma as a single treatment modality for alopecia and skin rejuvenation and in combination with laser skin treatment and fat grafting. There is, however, a considerable amount of variability in the processing, preparation, and treatment modalities. CONCLUSIONS: Despite a lack of standardized protocols for platelet-rich plasma preparation and a scarcity of large-scale studies with long-term follow-up, there is convincing evidence with objective measurement modalities that display positive outcomes after treatment for skin rejuvenation, hair regrowth, wound healing, and fat graft take.

THE EFFECT OF PHOTODYNAMIC THERAPY AND PLATELET-ENRICHED PLASMA ON THE HEALING OF SKIN RADIATION ULCERS INFECTED BY STAPHYLOCOCCUS AUREUS. / VPLYV FOTODYNAMIChNOÏ TERAPIÏ TA ZBAGAChENOÏ TROMBOTsYTAMY PLAZMY NA PROTsESY ZAGOIeNNIa PROMENEVYKh VYRAZOK ShKIRY, INFIKOVANYKh STAPHYLOCOCCUS AUREUS.

OBJECTIVE: To determine in experiment the quality of healing of skin radiation ulcers infected with Staphylococcusaureus (S. aureus) under the photodynamic therapy (PDT) administration and the use of platelet-rich plasma (PRP). MATERIALS AND METHODS: The experiment was performed on 95 male WAG rats of 6 months of age, which were divided into three groups. Group 1 included animals in whom a skin radiation ulcers in the thigh area was simulated, followed by application of a 0.2 ml suspension of reference strain of S. aureus to its surface on the 7th day after irradiation. Group 2 included animals with S. aureus-infected skin radiation ulcers, in whom the PET was administered aday after infection contamination. Group 3 included animals with S. aureus-infected skin radiation ulcers, in whomthe PDT was administered a day after infection in the morning, and the PRP was manifold injected in periwound areain the afternoon. The skin with underlying soft tissues from the area of radiation damage were the material for morphological examination. The hematoxylin and eosin, picrofuxin according to van Gizon, Mallory staining wereapplied to micropreparations. A morphometric study was conducted. RESULTS: In animals with skin radiation ulcers, in whom the PDT was administered upon infection with S. aureus(group 2), compared with animals with simulated infected skin radiation ulcers without treatment (group 1), Theactivation (i.e. accelerating) of the healing occurred for the period from the 14th to the 52nd day of experiment dueto the active processes of wound cleansing from necrotized tissues, less pronounced inflammatory changes in thelesion, and active of appearance and maturation of granulation tissue, less pronounced hemodynamic, ischemic andalternative disorders in the dermis, hypodermis, muscle tissue surrounding the wound cavity, activation of proliferative processes in epithelial layer localized in the marginal parts of the wound. Formation of pathological (hypertrophic or keloid) scar of the skin was the result of healing of skin radiation ulcer infected with S. aureus. In animalswith radiation ulcers infected with S. aureus, in the case of PDT and PRP (group 3) the regenerative process wasdirected not only at accelerating the rate of healing, but also on restoration of original structure of the lost parts ofthe skin compared with only PDT administration (group 2). Acceleration of the healing of the infected skin radiation ulcer in animals of groups 2 and 3 was due to similar processes. CONCLUSIONS: Photodynamic therapy activates and accelerates the healing process of skin radiation ulcers infectedwith S. aureus and leads to formation of a pathological scar (hypertrophic or keloid). Healing of the infected S. aureusradiation ulcers occurs more actively upon the photodynamic therapy administration in combination with multipleperiwound injections of the platelet-enriched plasma, compared with only photodynamic therapy administration,and finishes with an organotypic regeneration and almost complete skin recovery.

PLGA-PEG Nanoparticles Show Minimal Risks of Interference with Platelet Function of Human Platelet-Rich Plasma.

The expansion of nanotechnology for drug delivery applications has raised questions regarding the safety of nanoparticles (NPs) due to their potential for interacting at molecular and cellular levels. Although polymeric NPs for drug delivery are formulated using FDA-approved polymers such as lactide- and glycolide-based polymers, their interactions with blood constituents, remain to be identified. The aim of this study was to determine the impact of size-selected Poly-lactide-co-glycolide-polyethylene glycol (PLGA-PEG) NPs on platelet activity. The NPs of 113, 321, and 585 nm sizes, were formulated and their effects at concentrations of 0-2.2 mg/mL on the activation and aggregation of platelet-rich plasma (PRP) were investigated. The results showed that NPs of 113 nm did not affect adenosine diphosphate (ADP)-induced platelet aggregation at any NP concentration studied. The NPs of 321 and 585 nm, at concentrations ≥0.25 mg/mL, reduced ADP-activated platelet aggregation. The platelet activation profile remained unchanged in the presence of investigated NPs. Confocal microscopy revealed that NPs were attached to or internalised by platelets in both resting and activated states, with no influence on platelet reactivity. The results indicate minimal risks of interference with platelet function for PLGA-PEG NPs and that these NPs can be explored as nanocarriers for targeted drug delivery to platelets.

Platelet-Rich Plasma (PRP) in Breast Cancer Patients: An Application Analysis of 163 Sentinel Lymph Node Biopsies.

INTRODUCTION: Literature shows platelet-rich plasma (PRP) to improve overall outcomes in orthopedics, dermatology, ophthalmology, gynecology, and plastic surgery. Data on oncological patients is very limited. Only one publication is available on PRP in breast cancer patients. This work evaluated PRP in sentinel node biopsy procedures for breast cancer patients in terms of complication rates and oncological short-term follow-up. METHODS: The evaluated PRP was ACP®, i.e., autologous conditioned plasma by Arthrex®. Between 2015 and 2018, 163 patients were offered to receive an ACP®/PRP injection in their lymph node biopsy site. Recruitment resulted in an approximate one-to-one ratio for analysis. Endpoints were major (revision) and minor (seroma, hematoma, and infection) complications rates as well as distant metastases, local recurrence, and overall survival. Median follow-up was 30 months. RESULTS: Complication rates and oncological follow-up showed PRP to be applicable to use in a sentinel node biopsy scenario in breast cancer patients. There were 0 revisions in the ACP®/PRP group and 1.2% revisions in the control group (not significant). Oncological follow-up showed zero (0) distant metastases and local recurrences as well as a 100% 30-month overall survival. CONCLUSIONS: This is the first analysis of ACP®/PRP used in breast cancer patients in a sentinel node biopsy setting worldwide. PRP does not seem to increase rates of local recurrence within this 30-month follow-up time frame. Also, trend towards decreasing complication rates could be shown.