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Platelet-rich plasma (PRP) is a biological blood-derived therapeutic obtained from whole blood that contains higher levels of platelets. PRP has been primarily used to mitigate joint degeneration and chronic pain in osteoarthritis (OA). This clinical applicability is based mechanistically on the release of several proteins by platelets that can restore joint homeostasis. Platelets are the primary source of brain-derived neurotrophic factor (BDNF) outside the central nervous system. Interestingly, BDNF and PRP share key biological activities with clinical applicability for OA management, such as anti-inflammatory, anti-apoptotic, and antioxidant. However, the role of BDNF in PRP therapeutic activities is still unknown. Thus, this work aimed to investigate the implications of BDNF in therapeutic outcomes provided by PRP therapy in vitro and in-vivo, using the MIA-OA animal model in male Wistar rats. Initially, the PRP was characterized, obtaining a leukocyte-poor-platelet-rich plasma (LP-PRP). Our assays indicated that platelets activated by Calcium release BDNF, and suppression of M1 macrophage polarization induced by LP-PRP depends on BDNF full-length receptor, Tropomyosin Kinase-B (TrkB). OA animals were given LP-PRP intra-articular and showed functional recovery in gait, joint pain, inflammation, and tissue damage caused by MIA. Immunohistochemistry for activating transcriptional factor-3 (ATF-3) on L4/L5 dorsal root ganglia showed the LP-PRP decreased the nerve injury induced by MIA. All these LP-PRP therapeutic activities were reversed in the presence of TrkB receptor antagonist. Our results suggest that the therapeutic effects of LP-PRP in alleviating OA symptoms in rats depend on BDNF/TrkB activity.

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The discovery of prions has challenged dogmas and has revolutionized our understanding of protein-misfolding diseases. The concept of self-propagation via protein conformational changes, originally discovered for the prion protein (PrP), also applies to other proteins that exhibit similar behavior, such as alpha-synuclein (aSyn), a central player in Parkinson's disease and in other synucleinopathies. aSyn pathology appears to spread from one cell to another during disease progression, and involves the misfolding and aggregation of aSyn. How the transfer of aSyn between cells occurs is still being studied, but one important hypothesis involves receptor-mediated transport. Interestingly, recent studies indicate that the cellular prion protein (PrPC ) may play a crucial role in this process. PrPC has been shown to act as a receptor/sensor for protein aggregates in different neurodegenerative disorders, including Alzheimer's disease and amyotrophic lateral sclerosis. Here, we provide a comprehensive overview of the current state of knowledge regarding the interaction between aSyn and PrPC and discuss its role in synucleinopathies. We examine the properties of PrP and aSyn, including their structure, function, and aggregation. Additionally, we discuss the current understanding of PrPC 's role as a receptor/sensor for aSyn aggregates and identify remaining unanswered questions in this area of research. Ultimately, we posit that exploring the interaction between aSyn and PrPC may offer potential treatment options for synucleinopathies.

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The prevalence of partial rotator cuff tears (PRCTs) is high in the general population. Our hypothesis is that barbotage, when associated with platelet-rich plasma (PRP), is an effective method for healing these tears. The aim of this study was to compare the effects of barbotage with or without PRP on the healing of partial supraspinatus tendon tears (PSTTs). This study assessed the Western Ontario Rotator Cuff Index score and ultrasound (US) images at 6 weeks and 6 months after treatment. Patients in both groups showed clinical improvement, with no significant difference in scores at 6 weeks. However, at 6 months, the PRP group exhibited significant improvement (p = 0.019). Both groups experienced a reduction in ST tear size, but the PRP group demonstrated a significant enhancement at 6 weeks and 6 months. In conclusion, the US-guided barbotage technique, whether associated with PRP or saline solution, proved to be an effective treatment for clinical improvement and reduction in the size of PSTT. Better clinical improvement results were observed with PRP at 6 months. The combination of PRP with barbotage was superior in reducing the size of the ST tear at both 6 weeks and 6 months, resulting in complete healing in 79.3% of the tears.

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At least two million people in the United States of America live with lost limbs, and the number is expected to double by 2050, although the incidence of amputations is significantly greater in other parts of the world. Within days to weeks of the amputation, up to 90% of these individuals develop neuropathic pain, presenting as phantom limb pain (PLP). The pain level increases significantly within one year and remains chronic and severe for about 10%. Amputation-induced changes are considered to underlie the causation of PLP. Techniques applied to the central nervous system (CNS) and peripheral nervous system (PNS) are designed to reverse amputation-induced changes, thereby reducing/eliminating PLP. The primary treatment for PLP is the administration of pharmacological agents, some of which are considered but provide no more than short-term pain relief. Alternative techniques are also discussed, which provide only short-term pain relief. Changes induced by various cells and the factors they release are required to change neurons and their environment to reduce/eliminate PLP. It is concluded that novel techniques that utilize autologous platelet-rich plasma (PRP) may provide long-term PLP reduction/elimination.

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Cellular therapy and platelet-rich plasma (PRP) have been used as a treatment for skin wounds. Previous evidence has shown that mesenchymal stromal cells (MSC) may improve skin wound healing. In contrast, contradictory effects have been reported by using PRP treatment on skin wound healing. However, there is evidence that PRP constitutes an excellent scaffold for tissue engineering. In this work, we aim to study the effect of MSC on skin wound healing. We used an experimental murine model of full-thickness wounds. Wounds were treated with human bone marrow-MSC contained in a PRP clot. Untreated or PRP-treated wounds were used as controls. Wound healing was evaluated by macroscopic observation and histological analysis at day 7 post-wounding. Immunohistochemical studies were performed to detect the presence of epithelial progenitor cells (EPC) and the expression of basic fibroblast growth factor (bFGF). MSC/PRP implantation induced a significant wound closure and re-epithelialization as compared with the controls. Increase of CD34+ cells and bFGF was observed in the wounds treated with MSC/PRP. Our results show that MSC included in PRP clot induce cutaneous wound repair by promoting re-epithelialization, migration of EPC and expression of bFGF. PRP alone does not exert a significant effect on wound healing. Our results support the possible clinical use of MSC in PRP scaffold as potential treatment of skin wounds.

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Uncontrolled assembly/disassembly of physiologically formed liquid condensates is linked to irreversible aggregation. Hence, the quest for understanding protein-misfolding disease mechanism might lie in the studies of protein:nucleic acid coacervation. Several proteins with intrinsically disordered regions as well as nucleic acids undergo phase separation in the cellular context, and this process is key to physiological signaling and is related to pathologies. Phase separation is reproducible in vitro by mixing the target recombinant protein with specific nucleic acids at various stoichiometric ratios and then examined by microscopy and nanotracking methods presented herein. We describe protocols to qualitatively assess hallmarks of protein-rich condensates, characterize their structure using intrinsic and extrinsic dyes, quantify them, and analyze their morphology over time. Analysis by nanoparticle tracking provides information on the concentration and diameter of high-order protein oligomers formed in the presence of nucleic acid. Using the model protein (globular domain of recombinant murine PrP) and DNA aptamers (high-affinity oligonucleotides with 25 nucleotides in length), we provide examples of a systematic screening of liquid-liquid phase separation in vitro.

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Introducción: El plasma rico en plaquetas (PRP) se encuentra en desarrollo desde los años 80, asociado con aplicaciones en medicina cardíaca, traumatológica y dermatológica. El PRP es una preparación autóloga, con una concentración de plaquetas por sobre el valor normal en sangre periférica, que se obtiene a partir de su centrifugación siguiendo diferentes protocolos que fueron valorados en distintas revisiones sistemáticas. El plasma luego se activa con trombina o cloruro cálcico, o por lisis física (ultrasonido o frizado). El PRP contiene factores de crecimiento, citoquinas y proteínas de adhesión que, al aplicarse en la lesión, favorecen la hemostasia, la síntesis de tejido conectivo y la revascularización. El producto se aplica en solución o gel. Se intentaron diferentes clasificaciones del PRP para estandarizarlo, sin éxito. Se conceptualizó la receta del PRP para aplicación clínica, que presentó las siguientes características: valores altos de plaquetas, disminución de la contaminación de glóbulos rojos, presencia de neutrófilos y leucocitos para el éxito terapéutico. Protocolo y casos: Se presenta el protocolo de preparación de PRP de centrifugación única de 7 minutos a 1400 rpm, con activación por medio de gluconato de calcio según la siguiente proporción: 3 ml plasma/0.4 ml gluconato cálcico. Además, se informan tres casos de úlceras de pie diabético de nuestra institución. Conclusión: El PRP no presenta complejidad en su preparación y aplicación, por lo que es factible de realizar en el primer nivel de atención que cuente con los recursos materiales y profesionales con conocimiento en el abordaje de heridas crónicas.

Introduction: Platelet-rich plasma (PRP) has been under development since the 1980s, associated with applications in cardiac, traumatological, and dermatological medicine. PRP is an autologous preparation with a platelet concentration above the normal value in peripheral blood that is obtained from its centrifugation following different protocols that were evaluated in different systematic reviews. The plasma is then activated with thrombin or calcium chloride, or by physical lysis (ultrasound or friz). PRP contains growth factors, cytokines, and adhesion proteins that, when applied to the lesion, favor hemostasis, connective tissue synthesis, and revascularization. The product is applied in solution or gel. Different classifications of the PRP were used with the intention of standardizing the procedure without success. The PRP recipe for clinical application was conceptualized. It presented the following characteristics: high platelet values, decreased red blood cell contamination, presence of neutrophils and leukocytes for therapeutic success. Protocol and cases: The PRP preparation protocol for single centrifugation for 7 minutes at 1400 rpm with activation through calcium gluconate is presented according to the following ratio: 3 ml plasma/0.4 ml of calcium gluconate. Three cases of diabetic foot ulcers from our institution are reported. Conclusion: The PRP does not present complexity in its preparation and application, so it is feasible to perform it in the first level of care that has the material and professional resources with knowledge in the approach to chronic wounds.

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Platelet-rich plasma (PRP) is an autologous blood product containing growth factors and proteins, widely employed in the clinical setting for tissue repair. Robust evidence in basic science literature has facilitated clinical research involving PRP for patients with disc disease and lumbar pain. Degenerative disc disease (DDD) has been identified as a significant contributor to lower back pain, with approximately 40% of patients under 30 and 90% of those over 50 experiencing lumbar pain showing MRI findings consistent with degenerative changes in intervertebral discs. Regenerative medicine within the disc has primarily been studied in patients with chronic, untreatable lumbar pain. Objective: to understand the available evidence regarding the efficacy of PRP in lumbar disc herniation. By understanding the scientific evidence supporting PRP as a lumbar disc herniation treatment, a research project can be developed, providing the theoretical foundation for implementing this therapy in the Mexican population. A search was conducted using PUBMED, ClinicalKey (Elsevier), Medscape, Science Direct, and Google Scholar databases. Conclusions: despite promising results in several studies on intradiscal PRP injection, small sample sizes and non-standardized graft preparation procedures have hindered these research efforts.

El plasma rico en plaquetas (PRP) es un producto sanguíneo autólogo que contiene factores de crecimiento y proteínas y se ha utilizado en todo el entorno clínico para la reparación de tejidos. La fuerte evidencia en la literatura de ciencias básicas ha permitido la investigación clínica que involucra PRP para pacientes con enfermedad del disco y dolor lumbar. La enfermedad degenerativa del disco (DDD) se ha establecido como un importante contribuyente a la causa del dolor lumbar: aproximadamente el 40% de los pacientes menores de 30 años y el 90% de los pacientes mayores de 50 años que tienen dolor lumbar también muestran hallazgos de imágenes de resonancia magnética (IRM) que son consistentes con cambios degenerativos dentro de los discos intervertebrales. La medicina regenerativa intradiscal se ha estudiado principalmente en pacientes con dolor lumbar crónico intratable. Objetivo: conocer la evidencia disponible sobre la eficacia del PRP en hernias de disco lumbar. Al conocer la evidencia científica disponible del PRP como tratamiento de hernia discal lumbar se podrá desarrollar un proyecto de investigación, lo cual sustentará las bases teóricas para realizar esta terapia en la población mexicana. Se realizó búsqueda en base de datos PUBMED, ClinicalKey (Elsevier), Medscape, Science Direct, Google Scholar. Conclusiones: aunque varias investigaciones han arrojado resultados prometedores con respecto a la inyección intradiscal de PRP los tamaños de muestra pequeños y los procedimientos de preparación de injertos no estandarizados obstaculizaron estos esfuerzos de investigación.

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Platelet rich plasma samples from 50 healthy horses of five different breeds (Thoroughbreds - TB, Brazilian Criollo Horses - BCH, Brazilian Sport Horses - BSH, Miniature Horses - MH and Crossbred Horses - CB), were investigated as to breed, age, and gender effect for platelet concentration. Moreover, a score for physical analysis was established to correlate PRP physical aspect with platelet count. Platelet count was performed by an automatic hematology analyzer and by manual count. PRP physical analysis was based on color, aspect, and capacity to separate blood components. MH showed significant higher platelet concentration than BSH (p<0.05), while the other breed comparisons showed no significant difference. There was no significant difference for gender but there was a weak correlation of age with PRP platelet concentrations (rs = -0.24). Most of the PRP presented yellow color, the separation of blood components showed no correlation, but the aspect showed a moderate correlation (rs = 0.30) with platelet count. Results suggest that PRP platelet concentration can be influenced by intrinsic factors such as breed. Additionally, the analysis of PRP aspect can help to evaluate the quality of the product when there is no access to platelet counts.

Amostras de plasma rico em plaquetas de 50 cavalos saudáveis, de cinco raças diferentes (Puro Sangue de Corrida, Crioula, Brasileiro de Hipismo, Pônei Brasileiro e sem raça definida), foram investigadas quanto à concentração plaquetária em relação à raça, à idade e ao sexo. Além disso, um escore foi estabelecido para correlacionar o aspecto físico do PRP com a contagem plaquetária. A contagem celular foi realizada por um analisador hematológico automático e pelo método manual. A análise física baseou-se na cor, no aspecto e na capacidade de separar hemocomponentes. Pôneis tiveram concentração plaquetária significativamente maior que os Brasileiros de Hipismo (P<0,05), mas as demais comparações entre raças não apresentaram diferença quanto à contagem plaquetária. Não houve diferença para o gênero, mas a idade demonstrou correlação fraca com as concentrações plaquetárias do PRP (rs = -0,24). A maioria dos PRPs apresentaram coloração amarela, e a separação dos hemocomponentes não mostrou correlação com a contagem plaquetária, mas o aspecto apresentou uma correlação moderada (rs = 0,30). Os resultados deste estudo sugerem que a concentração plaquetária do PRP pode ser influenciada por fatores intrínsecos, como a raça. Além disso, a análise do aspecto do PRP pode ajudar na avaliação da qualidade do produto quando não há acesso à contagem plaquetária.

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Inteins are genetic mobile elements that are inserted within protein-coding genes, which are usually housekeeping genes. They are transcribed and translated along with the host gene, then catalyze their own splicing out of the host protein, which assumes its functional conformation thereafter. As Prp8 inteins are found in several important fungal pathogens and are absent in mammals, they are considered potential therapeutic targets since inhibiting their splicing would selectively block the maturation of fungal proteins. We developed a target-based drug screening system to evaluate the splicing of Prp8 intein from the yeast pathogen Cryptococcus neoformans (CnePrp8i) using Saccharomyces cerevisiae Ura3 as a non-native host protein. In our heterologous system, intein splicing preserved the full functionality of Ura3. To validate the system for drug screening, we examined cisplatin, which has been described as an intein splicing inhibitor. By using our system, new potential protein splicing inhibitors may be identified and used, in the future, as a new class of drugs for mycosis treatment. Our system also greatly facilitates the visualization of CnePrp8i splicing dynamics in vivo.

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Diabetic foot ulcer is a severe Diabetic Mellitus-associated complication. It is induced by poor glycemic control, which leads to peripheral neuropathy and vascular diseases. Platelet-rich plasma could be beneficial for healing processes due to its active biomolecules that promotes immunomodulation, angiogenesis, cell proliferation and analgesia.

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Sticky bone, a growth factor-enriched bone graft matrix, is a promising autologous material for bone tissue regeneration. However, its production is strongly dependent on manual handling steps. In this sense, a new device was developed to simplify the confection of the sticky bone, named Sticky Bone Preparation Device (SBPD®). The purpose of this pilot study was to investigate the suitability of the SBPD® to prepare biomaterials for bone regeneration with autologous platelet concentrates. The SBPD® allows the blending of particulate samples from synthetic, xenograft, or autogenous bone with autologous platelet concentrates, making it easy to use and avoiding the need of further manipulations for the combination of the materials. The protocol for the preparation of sticky bone samples using the SBPD® is described, and the resulting product is compared with hand-mixed SB preparations regarding in vitro parameters such as cell content and the ability to release growth factors and cytokines relevant to tissue regeneration. The entrapped cell content was estimated, and the ability to release biological mediators was assessed after 7 days of incubation in culture medium. Both preparations increased the leukocyte and platelet concentrations compared to whole-blood samples (p < 0.05), without significant differences between SB and SBPD®. SBPD® samples released several growth factors, including VEGF, FGFb, and PDGF, at concentrations physiologically equivalent to those released by SB preparations. Therefore, the use of SBPD® results in a similar product to the standard protocol, but with more straightforward and shorter preparation times and less manipulation. These preliminary results suggest this device as a suitable alternative for combining bone substitute materials with platelet concentrates for bone tissue regeneration.

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BACKGROUND: The pathogenesis and treatment of lateral elbow epicondylitis (LEE) are still controversial. The purpose of the current study was to evaluate the production of inflammatory cytokines by LEE-derived cells and to compare the anti-inflammatory effect of triamcinolone acetonide with platelet-rich plasma (PRP) on cytokines production in primary culture of these cells. METHODS: Third passage cells from primary cultures of LEE were assessed for the production of the cytokines IL-1ß, IL-6, IL-8, IL-10 and TNF-α by immune-enzymatic assay (ELISA), after the treatment with 1, 10 and 100 µM triamcinolone compared to no treated controls at the time points 6, 12, 18, 24, 48, 72 and 96 h, and to PRP at 48, 72 and 96 h. RESULTS: The cytokines IL-6 and IL-8 were produced in high concentrations by LEE cells. One, 10 and 100 µM triamcinolone induced significant decrease in the production of IL-6 and IL-8 at 48, 72 and 96 h, adding the time point 12 h for IL-8. Compared to controls, PRP caused a significant increase in the production of IL-6 and IL-8 and there was a significant increase in IL-10 production with the use of 100 µM triamcinolone at 48 h. The production of IL1-ß and TNF-α was very low and did not change when the cultures were treated with triamcinolone or PRP. CONCLUSION: LEE-derived cells produce IL-6 and IL-8, confirming the inflammatory nature of this condition. While triamcinolone inhibited the production of IL-6 and IL-8 by LEE cells, PRP induced an increase in these cytokines compared with controls.

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Platelet-rich plasma (PRP) has been proposed as an agent to accelerate the healing process and stimulate the regenerative capacity of tissues due to its abundance of growth factors. A large variety of kits and protocols are available to obtain PRP by different cell-separation systems. However, the lack of standardization may lead to inconsistent results. The aim of this study was to characterize cellular composition, platelet parameters using the ADVIA 120 flow cytometer, and TGF-ß1 concentration from the PRP product obtained through a closed system, using simple centrifugation. Six clinically healthy horses were used in this study. The protocol in the closed system resulted in approximately 1.6-fold higher platelet and approximately 2.0-fold lower white blood cell concentrations in comparison with whole blood values. The evaluated system was efficient in concentrating platelets and in retrieving a small number of leukocytes, using a protocol of single centrifugation at low speed.

O plasma rico em plaquetas (PRP) tem sido proposto como um agente para acelerar o processo de cicatrização e estimular a capacidade regenerativa dos tecidos, devido à sua abundância de fatores de crescimento. Uma grande variedade de kits e de protocolos está disponível para obtenção de PRP, utilizando-se diferentes sistemas de separação de células. No entanto, a falta de padronização pode levar a resultados inconsistentes. O objetivo deste estudo foi caracterizar a composição celular, os parâmetros plaquetários pelo citômetro de fluxo ADVIA 120 e a concentração de TGF-ß1 do PRP obtido em sistema fechado, por centrifugação simples. Seis cavalos clinicamente saudáveis ​​foram usados ​​neste estudo. O protocolo no sistema fechado resultou em concentrações de plaquetas aproximadamente 1,6 vez maior e concentrações de leucócitos aproximadamente 2,0 vezes menores em comparação com os valores do sangue total. O sistema avaliado foi eficiente na concentração de plaquetas e na recuperação de um pequeno número de leucócitos, utilizando um protocolo de centrifugação única em baixa velocidade.

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OBJECTIVE: To evaluate whether platelet-rich plasma (PRP) optimizes endometrial thickness (EMT) and improves live birth rates (LBR) in women with refractory thin endometrium due to varied aetiology during fresh in vitro fertilization (IVF) and frozen-thawed embryo transfer (FET). METHODS: A prospective interventional study was conducted at the ART Centre of a tertiary care academic hospital. Twenty-two infertile women with refractory thin endometrium (<7mm) despite standard hormone replacement therapy were assessed. Twenty patients underwent 26 PRP cycles from December 2018 - June 2020 during fresh IVF-ET and FET. Primary endpoint was expansion of EMT and secondary outcomes were implantation rate (IR), clinical pregnancy rate (CPR) and LBR in fresh and FET cycles and aetiology wise. RESULTS: Mean EMT increased significantly following PRP administration (p<0.001) with average increase of 1.07mm and 0.83mm after first PRP (p<0.001) during fresh IVF and FET, respectively. CPR, IR and LBR showed no significant difference when compared during fresh vs. FET cycles (p>0.05). PRP led to significant increase in EMT in tuberculosis (TB), diminished ovarian reserve (DOR) and polycystic ovary syndrome (PCOS) (p<0.001). There was no significant difference in CPR, IR and LBR among three aetiological factors (p>0.05). Overall, clinical pregnancy and LBR reached up to 20% and 25%, respectively. No adverse reactions were reported. CONCLUSIONS: PRP enhances EMT significantly during fresh and FET cycles in thin endometrium associated with TB, PCOS and DOR, thus improving the CPR and LBR in these low prognosis patients.

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OBJECTIVE: Repeated implantation failure (RIF) is a major challenge in reproductive medicine. On the other hand, there has not yet been established a confirmed outcome regarding the usage of platelet-rich plasma (PRP) in women undergoing intracytoplasmic injection (ICSI) or in-vitro fertilization (IVF); hence, the objective of this study was to evaluate the effect of the intrauterine infusion of PRP on pregnancy outcomes in women undergoing ICSI. METHODS: In this prospective double-blind clinical trial, 100 women with at least two previous unexplained RIF, who were candidates for frozen-thawed embryo transfer, were allocated into two groups. One subgroup of patients was treated by intrauterine infusion of PRP (0.5CC, contained platelet 4-5 times more than a peripheral blood sample, which was performed 48 hours before blastocyst transfer) and the other subgroup was treated by intrauterine catheterization only. We compared the implantation rates between the two groups. RESULTS: The pregnancy rate was 20% in the intervention subgroup, while in the control subgroup it was 13.33%; therefore, there was a significant statistical difference between the two groups. CONCLUSIONS: According to this paper, PRP could be successful in improving the pregnancy outcome in RIF patients, and we highly recommend other studies with larger samples to confirm the PRP therapy efficacy in RIF patients.

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After the discovery of prion phenomenon, the physiological role of the cellular prion protein (PrP C ) remained elusive. In the past decades, molecular and cellular analysis has shed some light regarding interactions and functions of PrP C in health and disease. PrP C , which is located mainly at the plasma membrane of neuronal cells attached by a glycosylphosphatidylinositol (GPI) anchor, can act as a receptor or transducer from external signaling. Although the precise role of PrP C remains elusive, a variety of functions have been proposed for this protein, namely, neuronal excitability and viability. Although many issues must be solved to clearly define the role of PrP C , its connection to the central nervous system (CNS) and to several misfolding-associated diseases makes PrP C an interesting pharmacological target. In a physiological context, several reports have proposed that PrP C modulates synaptic transmission, interacting with various proteins, namely, ion pumps, channels, and metabotropic receptors. PrP C has also been implicated in the pathophysiological cell signaling induced by ß-amyloid peptide that leads to synaptic dysfunction in the context of Alzheimer's disease (AD), as a mediator of Aß-induced cell toxicity. Additionally, it has been implicated in other proteinopathies as well. In this review, we aimed to analyze the role of PrP C as a transducer of physiological and pathological signaling.

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BACKGROUND: Post-spinal back pain is suggested to occur as a result of a localized inflammatory response that is often associated with some degree of muscle spasm. We aimed to evaluate the effect of platelet-rich plasma (PRP) in reducing the incidence of post-spinal back pain. METHODS: One hundred patients were randomly enrolled and scheduled for elective gynecological surgery under spinal anesthesia. After the subarachnoid block, group A (placebo) received 2 mL of sodium chloride 0.9% injected into the track of spinal needle during its withdrawal (2 mm after outward withdrawal in muscles and subcutaneous tissues). While patients in group B (PRP); received 2 ml of PRP injected into the track of the spinal needle during its withdrawal. The primary outcome was the number of patients who developed post-spinal low back pain within the first week following the subarachnoid block. Secondary outcomes included the time of the first analgesic request and total meperidine consumption during the first 24 h postoperatively. RESULTS: Fifteen patients in the PRP group developed low back pain during the first week following subarachnoid block compared to 26 patients in the placebo group (p = 0.037). There was a significant decrease in the mean meperidine consumption during first 24 h postoperatively in PRP group (174 ±â€¯14 mg) compared to placebo group (210 ±â€¯22 mg) (p < 0.0001). Also, the first analgesic request was significantly delayed in PRP group (243 ±â€¯21 min.) compared to placebo group (185 ±â€¯31 min.) (p < 0.0001). CONCLUSION: This study demonstrated the positive effects of platelet-rich plasma on the prevention of post-spinal backache.

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BACKGROUND: Platelet-rich plasma (PRP) has a still conflicting efficacy for knee osteoarthritis (KOA) and might be a minimally invasive and safe treatment alternative. The potential benefit of only plasma (non-enriched) has never been investigated. Our aim was to evaluate the efficacy of intra-articular platelet-rich plasma (PRP) and plasma to improve pain and function in participants with KOA over 24 weeks. METHODS: Randomized, double-blind, placebo-controlled trial with 3 groups (n = 62): PRP (n = 20), plasma (n = 21) and saline (n = 21). Two ultrasound-guided knee injections were performed with a 2-week interval. The primary outcome was visual analog scale 0-10 cm (VAS) for overall pain at week 24, with intermediate assessments at weeks 6 and 12. Main secondary outcomes were: KOOS, OMERACT-OARSI criteria and TUGT. RESULTS: At baseline, 92% of participants were female, with a mean age of 65 years, mean BMI of 28.0 Kg/m2and mean VAS pain of 6.2 cm. Change in pain from baseline at week 24 were -2.9 (SD 2.5), -2.4 (SD 2.5) and -3.5 cm (SD 3.3) for PRP, plasma and saline, respectively (p intergroup = 0.499). There were no differences between the three groups at weeks 6 and 12. Similarly, there were no differences between groups regarding secondary outcomes. The PRP group showed higher frequency of adverse events (65% versus 24% and 33% for plasma and saline, respectively, p = 0.02), mostly mild transitory increase in pain. CONCLUSIONS: PRP and plasma were not superior to placebo for pain and function improvement in KOA over 24 weeks. The PRP group had a higher frequency of mild transitory increase in pain. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03138317 , 03/05/2017.

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Prion diseases have been described in humans and other mammals, including sheep, goats, cattle, and deer. Since mice, hamsters, and cats are susceptible to prion infection, they are often used to study the mechanisms of prion infection and conversion. Mammals, such as horses and dogs, however, do not naturally contract the disease and are resistant to infection, while others, like rabbits, have exhibited low susceptibility. Infection involves the conversion of the cellular prion protein (PrPC) to the scrapie form (PrPSc), and several cofactors have already been identified as important adjuvants in this process, such as glycosaminoglycans (GAGs), lipids, and nucleic acids. The molecular mechanisms that determine transmissibility between species remain unclear, as well as the barriers to transmission. In this study, we examine the interaction of recombinant rabbit PrPC (RaPrP) with different biological cofactors such as GAGs (heparin and dermatan sulfate), phosphatidic acid, and DNA oligonucleotides (A1 and D67) to evaluate the importance of these cofactors in modulating the aggregation of rabbit PrP and explain the animal's different degrees of resistance to infection. We used spectroscopic and chromatographic approaches to evaluate the interaction with cofactors and their effect on RaPrP aggregation, which we compared with murine PrP (MuPrP). Our data show that all cofactors induce RaPrP aggregation and exhibit pH dependence. However, RaPrP aggregated to a lesser extent than MuPrP in the presence of any of the cofactors tested. The binding affinity with cofactors does not correlate with these low levels of aggregation, suggesting that the latter are related to the stability of PrP at acidic pH. The absence of the N-terminus affected the interaction with cofactors, influencing the efficiency of aggregation. These findings demonstrate that the interaction with polyanionic cofactors is related to rabbit PrP being less susceptible to aggregation in vitro and that the N-terminal domain is important to the efficiency of conversion, increasing the interaction with cofactors. The decreased effect of cofactors in rabbit PrP likely explains its lower propensity to prion conversion.