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Globally, osteoarthritis (OA) is the most prevalent joint disease and is characterized by infiltration of M1 macrophages in the synovium, anabolic–catabolic imbalance of the extracellular matrix (ECM), increased articular shear force and overproduction of reactive oxygen species (ROS). Disease-modifying OA drugs are not yet available, and treatments for OA focus solely on reducing pain and inflammation and have limited therapeutic effect. Herein, we developed an injectable self-lubricating poly(N-acryloyl alaninamide) (PNAAA) hydrogel loaded with platelet lysate (PL) (termed "PNAAA@PL") for treating OA. Tribological and drug release tests revealed suitable lubrication properties and sustained release of bioactive factors in PNAAA@PL. In vitro experiments showed that PNAAA@PL alleviated interleukin-1β (IL-1β)-induced anabolic–catabolic imbalance of chondrocytes and repolarized pro-inflammatory M1 macrophages to the anti-inflammatory M2 phenotype via intracellular ROS scavenging. Additionally, the PNAAA@PL hydrogel enhanced the migratory capacity and chemotaxis ability of stem cells, which are essential for chondrogenesis. In vivo , the functionalized PNAAA@PL hydrogel acted like synovial fluid following intra-articular injection into a rat OA model with anterior cruciate ligament transection, ultimately attenuating cartilage degeneration and synovitis. According to molecular mechanism studies, PNAAA@PL repairs cartilage in the OA model by inhibiting the NF-ĸB pathway. Overall, this self-lubricating PNAAA@PL hydrogel offers a comprehensive strategy for preventing OA progression by engineering a biophysiochemical microenvironment to generate high-quality hyaline cartilage. [Display omitted] • Loading platelet lysate on hydrogels can delay the release of bioactive factors. • PNAAA@PL hydrogel attenuated joint degeneration by remodeling joint microenvironment. • Differentially expressed genes contributed to anti-OA abilities of PNAAA@PL hydrogel. • The synergy of lubrication and sustained bioactive factors delivery help treat OA. [ABSTRACT FROM AUTHOR]

Introduction: Osteoarthritis (OA) of the knee affects millions of people with sizable socioeconomic burden. Conventional treatment modalities are prioritized, turning to surgical intervention only when they have failed. However, these traditional modalities have shortcomings, only aiming to reduce pain rather than targeting the underlying pathophysiology. Recently, the use of biologics, including autologous peripheral blood-derived orthobiologics (APBOs), has increased and demonstrated great promise for the management of knee OA. Platelet-rich plasma (PRP) is the most widely used APBO, but its efficacy is still uncertain, attributed to lack of standardized formulation protocols, characterization, and patient variables. To overcome the limitations posed by PRP, the use of other APBOs such as platelet lysate (PL) has been considered. This review summarizes the outcomes of clinical studies involving PL to manage OA of the knee. Methods: Multiple databases (Scopus, Embase, PubMed, and Web of Science) were searched employing terms "platelet lysate" and "knee osteoarthritis" for articles published in the English language to August 15, 2024, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Only three clinical studies fulfilled our search and inclusion criteria. Intra-articular injection of three doses of PL injected every 3–4 weeks is safe and efficacious, resulting in statistically significant improvements in different patient-reported outcome measures at 6–12 months follow-up. Conclusion: The existing published peer-reviewed literature suggests that intra-articular injection of PL is safe and can decrease pain and increase function in patients with knee OA. Nonetheless, given the dearth of pertinent literature, more adequately powered, multicenter, prospective, non-randomized and randomized controlled studies with extended follow-up are needed to confirm the effectiveness of PL in knee OA. Further comparative studies to help clinicians in choosing the best APBO for knee OA treatment are also warranted. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) is a leading cause of heart failure, disability and mortality worldwide. In this study, the effects of intramyocardial injection of human platelet lysate (HPL), bone marrow mesenchymal stem cells pretreated with HPL (PMSCs), and PMSC lysate (lys), alone and in combination were investigated on MI-induced by LAD ligation in male Wistar rats. The experiment was carried out on sham, vehicle (Veh), HPL, PMSCs, PMSC lysate (PMSC lys), HPL + PMSCs, and HPL + PMSC lys groups. SBP, DBP, and ± dp/dt max were monitored by the PowerLab physiograph. The MSC characteristics and CD31, NKX2.5, and cardiac troponin I (cTnI) contents were determined by flow cytometry, immunohistochemistry, and immunofluorescence, respectively. SBP, DBP, and ± dp/dt max that decreased in the MI group were recovered by HPL, PMSC, PMSC lys, HPL + PMSC, and HPL + PMSC lys treatments. CD31 density was higher in all treated groups compared to the Veh group. CD31 density in the HPL + PMSCs and HPL + PMSC lys groups was higher than in the PMSCs group. The number of Dil+/NKX2.5 + and Dil+/cTnI + cells was higher in the HPL + PMSCs group compared to the PMSCs group. The HPL and PMSCs mitigates heart injuries and cardiac dysfunction after MI. HPL provides an appropriate environment for cardiomyocyte differentiation from PMSCs. [ABSTRACT FROM AUTHOR]

Background/Objectives: Chronic skin wounds (CSWs) are a worldwide healthcare problem with relevant impacts on both patients and healthcare systems. In this context, innovative treatments are needed to improve tissue repair and patient recovery and quality of life. Cord blood platelet lysate (CB-PL) holds great promise in CSW treatment thanks to its high growth factors and signal molecule content. In this work, thermo-sensitive hydrogels based on an amphiphilic poly(ether urethane) (PEU) were developed as CB-PL carriers for CSW treatment. Methods: A Poloxamer 407®-based PEU was solubilized in aqueous medium (10 and 15% w/v) and added with CB-PL at a final concentration of 20% v/v. Hydrogels were characterized for their gelation potential, rheological properties, and swelling/dissolution behavior in a watery environment. CB-PL release was also tested, and the bioactivity of released CB-PL was evaluated through cell viability, proliferation, and migration assays. Results: PEU aqueous solutions with concentrations in the range 10–15% w/v exhibited quick (within a few minutes) sol-to-gel transition at around 30–37 °C and rheological properties modulated by the PEU concentration. Moreover, CB-PL loading within the gels did not affect the overall gel properties. Stability in aqueous media was dependent on the PEU concentration, and payload release was completed between 7 and 14 days depending on the polymer content. The CB-PL-loaded hydrogels also showed biocompatibility and released CB-PL induced keratinocyte migration and proliferation, with scratch wound recovery similar to the positive control (i.e., CB-PL alone). Conclusions: The developed hydrogels represent promising tools for CSW treatment, with tunable gelation properties and residence time and the ability to encapsulate and deliver active biomolecules with sustained and controlled kinetics. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To clarify the anti-inflammatory effect of platelet lysate (PL) on equine persistent synovitis by using a model of synovitis induced by monoiodoacetic acid (MIA). METHODS: Nonseptic synovitis was induced by administering MIA into both antebrachiocarpal joints of 6 clinically healthy horses on day 0. On days 23, 30, and 37, carpal circumference measurement and synovial fluid collection for assays (leucocytes, LDH, tumor necrosis factor-a, and TGF-ß1) were performed, after which PL was injected into 1 antebrachiocarpal joint and saline into the contralateral joint. Synovium and synovial fluid were obtained on day 44 for histological analysis and quantification of inflammation-related genes (matrix metalloproteinase-13, a disintegrin and metalloproteinase with thrombospondin motifs 4, receptor activator of nuclear factor β ligand, and collagen type I a2 chain) and the abovementioned proteins. RESULTS: The LDH level on day 44 was significantly lower in the PL-injected joint than in the saline-treated one. However, no significant differences were found in the other indices quantified, including osteoclast counts on the synovium. CONCLUSIONS: Multiple IA administration of PL does not exert anti-inflammatory effects on the equine persistent synovitis induced by MIA. CLINICAL RELEVANCE: Intra-articular PL administration did not alter many inflammatory biomarkers, suggesting that PL does not have a direct anti-inflammatory effect. However, the reduction in synovial LDH levels suggests that PL promoted joint tissue repair and may consequently alleviate inflammation at the site of administration. [ABSTRACT FROM AUTHOR]

Purpose: Chondrocyte‐based cell therapies are effective for the treatment of chondral lesions, but remain poorly indicated for diffuse lesions in the context of early osteoarthritis (OA). The aim of this study was to develop a protocol to obtain chondroprogenitor cells suitable for the treatment of diffuse chondral lesions within early OA. Methods: Cartilage cells were expanded at low density in human platelet lysate (hPL). A test was performed to exclude senescence. The expression of surface cluster of differentiation 146, cluster of differentiation 166, major histocompatibility complex (MHC)‐I and MHC‐II and of genes of interest were evaluated, as well as the trophic potential of these cells, by the assessment of lubricin and matrix production. The immunomodulatory potential was assessed through their co‐culture with macrophages. Results: Cartilage cells expanded at low density in hPL showed higher proliferation rate than standard‐density cells, no replicative senescence, low immunogenicity and expression of lubricin. Moreover, they presented an increased expression of chondrogenic and antihypertrophic markers, as well as a superior matrix deposition if compared to cells cultured at standard density. Cartilage cells induced on macrophages an upregulation of CD206, although a higher increase of CD163 expression was observed in the presence of low‐density cells. Conclusions: These findings lay the grounds to explore the clinical usefulness of low‐density cultured cartilage cells to treat diffuse lesions in early OA joints for both autologous and allogenic use. Level of Evidence: Not applicable. [ABSTRACT FROM AUTHOR]

Background: Among the emerging treatments for erectile dysfunction (ED), platelet-rich plasma (PRP), known for its ability to enhance tissue repair and regeneration, stands out as a promising therapeutic approach. In this innovative study, we aimed to assess the efficacy of intracavernous injections of platelet lysate (PL), a derivative of PRP, in improving erectile function among ED patients. Methods: We enrolled twenty-six patients, aged between 35 and 70 years (mean age 51.6 ± 11.3 years), who had been experiencing ED for over six months and had an International Index of Erectile Function-5 (IIEF-5) score of 21 or less. Participants received autologous PL injections intracavernously every two weeks for a total of five administrations. We assessed Erection Hardness Score (EHS) and International Index of Erectile Function-5 (IIEF-5) bi-weekly for 16 weeks and conducted penile Doppler ultrasounds pre- and post-treatment to record peak systolic velocity (PSV) and resistance index (RI). Results: Before treatment, the mean EHS was 2.15 ± 0.88 and IIEF-5 was 10.92 ± 5.28. Remarkable improvements were observed post-treatment, with the EHS significantly increasing to 3.15 ± 0.83 (p < 0.05) and IIEF-5 to 17.23 ± 5.26 (p < 0.05). Penile Doppler ultrasound exhibited an increase in both PSV and RI post-treatment, with the rise in RI being statistically significant. Conclusions: Our findings indicate that intracavernous injections of PL substantially enhance erectile function, as evidenced by improvements in EHS, IIEF-5, and the RI of penile Doppler ultrasound, without hemorrhagic events or other adverse reactions apart from temporary pain at the injection site during the 16-week follow-up period. These encouraging results suggest that PL injections are a safe and effective treatment modality for patients with moderate ED, potentially providing a less invasive and more physiologically friendly alternative to current ED management strategies. Trial registration: The study received approval from the Institutional Review Board of National Taiwan University Hospital (IRB Number 202008061RIPC, date of registration 08/28/2020). [ABSTRACT FROM AUTHOR]

Platelet lysate, derived from platelets, are valuable biological products rich in bioactive molecules. Their use promotes tissue healing and modulates inflammation. However, maintaining the stability and bioactivity of platelet lysate is challenging since they degrade rapidly at room temperature. This study focused on the possibility to confer enhanced stability to freeze-dried equine platelet lysate as an alternative to platelet-rich plasma (PRP). Platelet lysate (PL) was derived from PRP and freeze-dried either as such or using various adjuvants. Primary cell cultures of porcine Vascular Wall-Mesenchymal Stem Cells were treated with different PL formulations, and cell viability was assessed using an MTT assay. Overall, the addition of PL significantly improved cell viability as compared to controls without growth factor supplementation or with foetal bovine serum. Notably, the freeze-drying process maintained the effectiveness of the PL for at least a week. Furthermore, the study revealed that varying the horse as the source of PL could yield varying effects on cell viability. Detailed freeze-drying protocols were established, including freezing, primary drying and secondary drying phases, and the type of adjuvant. This study demonstrated the potential of freeze-dried equine PL as a viable alternative to PRP and highlighted the importance of precise freeze-drying protocols and adjuvants for standardization. Equine PL showed promise for medical treatment in horses, offering advantages such as extended shelf life, ease of handling, and reduced transportation costs, with the potential for broadened therapeutic usage.

Abstract Myocardial infarction (MI) is a leading cause of heart failure, disability and mortality worldwide. In this study, the effects of intramyocardial injection of human platelet lysate (HPL), bone marrow mesenchymal stem cells pretreated with HPL (PMSCs), and PMSC lysate (lys), alone and in combination were investigated on MI-induced by LAD ligation in male Wistar rats. The experiment was carried out on sham, vehicle (Veh), HPL, PMSCs, PMSC lysate (PMSC lys), HPL + PMSCs, and HPL + PMSC lys groups. SBP, DBP, and ± dp/dt max were monitored by the PowerLab physiograph. The MSC characteristics and CD31, NKX2.5, and cardiac troponin I (cTnI) contents were determined by flow cytometry, immunohistochemistry, and immunofluorescence, respectively. SBP, DBP, and ± dp/dt max that decreased in the MI group were recovered by HPL, PMSC, PMSC lys, HPL + PMSC, and HPL + PMSC lys treatments. CD31 density was higher in all treated groups compared to the Veh group. CD31 density in the HPL + PMSCs and HPL + PMSC lys groups was higher than in the PMSCs group. The number of Dil+/NKX2.5 + and Dil+/cTnI + cells was higher in the HPL + PMSCs group compared to the PMSCs group. The HPL and PMSCs mitigates heart injuries and cardiac dysfunction after MI. HPL provides an appropriate environment for cardiomyocyte differentiation from PMSCs.

Abstract Background Among the emerging treatments for erectile dysfunction (ED), platelet-rich plasma (PRP), known for its ability to enhance tissue repair and regeneration, stands out as a promising therapeutic approach. In this innovative study, we aimed to assess the efficacy of intracavernous injections of platelet lysate (PL), a derivative of PRP, in improving erectile function among ED patients. Methods We enrolled twenty-six patients, aged between 35 and 70 years (mean age 51.6 ± 11.3 years), who had been experiencing ED for over six months and had an International Index of Erectile Function-5 (IIEF-5) score of 21 or less. Participants received autologous PL injections intracavernously every two weeks for a total of five administrations. We assessed Erection Hardness Score (EHS) and International Index of Erectile Function-5 (IIEF-5) bi-weekly for 16 weeks and conducted penile Doppler ultrasounds pre- and post-treatment to record peak systolic velocity (PSV) and resistance index (RI). Results Before treatment, the mean EHS was 2.15 ± 0.88 and IIEF-5 was 10.92 ± 5.28. Remarkable improvements were observed post-treatment, with the EHS significantly increasing to 3.15 ± 0.83 (p

Purpose. The aim of the work is to compare the time of epithelization and the change in the thickness of the cornea in the treatment of erosions after corneal burns of 2–3 degrees and ulcers after keratitis with preserved amnion and amnion saturated with autologous PRP lysate. Materials and methods. To compare the effectiveness of preserved amnion and lysate-soaked PRP, 2 groups of patients were identified: the main group (amnion saturated with lysate PRP) and the comparison group (amnion without lysate PRP). Each group included patients with erosions after recent burns with an average area of 60 % of the cornea and ulcers after keratitis with a corneal thickness at the bottom of the ulcer of 382 microns in the experimental group and 393 microns in the comparison group. In the comparison group, ulcers were treated by covering the cornea with an amniotic membrane for 7–14 days, after which the amnion was removed and the condition of the cornea was monitored. An amniotic membrane saturated with PRP lysate was used in the experimental group. PRP lysate was made from autologous blood of patients in the laboratory of cell transplantation and immunotyping of the N.V. Sklifosovsky Research Institute of Emergency Medicine using a patented technology. To do this, platelet-rich plasma (PRP) with a platelet content of over 1000 thousand/ml was isolated from the blood of donors, which was then frozen at -80 °C and thawed at 0–4 °C in order to destroy cell membranes. Assessment of the condition of the cornea was carried out using clinical and instrumental studies, including biomicroscopy with fluorescein staining, photoregistration and OCT on the Heidelberg Engineering “OCT Spectralis” apparatus. Results. The use of an amniotic membrane saturated with PRP lysate led to epithelialization of erosions after recent burns in 1.3 months and a decrease in corneal edema by 247 microns, epithelialization of ulcers after keratitis in 1.3 months and an increase in the thickness of the cornea at the bottom of the ulcer by 62.5 microns. Treatment with conventional preserved amnion took 1.8 months before complete epithelization in recent burns with a decrease in corneal stroma edema by 193 microns, and epithelization of ulcers after keratitis required 1.6 months and ended with an increase in the thickness of the cornea at the site of the ulcer by 42 microns. Conclusion. The study showed that the presented method of treating erosions and ulcers of the cornea of various genesis using an amniotic membrane saturated with autologous PRP lysate allows achieving complete and persistent epithelialization in a shorter time and with fewer amnion coatings, unlike the comparison group. At the same time, patients do not need additional conservative treatment of epitheliopathies.

BACKGROUND: Platelet-derived extracellular vesicles are the most abundant vesicles in the circulation, rich in bioactive molecules, genetic material, proteins and other information molecules, involved in cellular communication and material exchange, not only has good procoagulant activity, but also has the promotion of tissue repair and regeneration, and has a wide range of applications in regenerative medicine. OBJECTIVE: To elaborate the secretion mechanism of platelet-derived extracellular vesicles, their application in regenerative medicine, and limiting factors for clinical transformation, and to provide some theoretical support for the clinical translation of platelet-derived extracellular vesicles. METHODS: A computerized search of the PubMed database from January 2005 to August 2023 was applied to articles relating to platelet-derived extracellular vesicles with the search terms “platelet-derived, platelet-rich plasma, extracellular vesicles, isolated, microvesicles exosomes, applications”. A total of 62 articles that met the subject criteria were finally included. RESULTS AND CONCLUSION: (1) Activated platelet-derived extracellular vesicles produce two types of vesicles, platelet-derived microparticles, whose secretion may be associated with the asymmetry of the actin cytoskeleton, and platelet-derived exosomes, which may be associated with the regulation of H+ -ATPase. (2) Platelet-derived extracellular vesicles are potential effectors of platelet concentrates and platelets themselves, and may intervene in tissue regeneration by promoting angiogenesis, influencing cellular behavior, promoting coagulation and hemostasis, and exerting inflammatory effects. (3) Platelet-derived extracellular vesicles have been reported preclinically in the field of regenerative medicine such as tissue injury, muscle regeneration, cartilage regeneration, and osteoarthritis, and clinical trial data are available as potential therapeutic approaches for wound healing. However, factors such as isolation methods, sample sources, and the types of activators limit the clinical translation of platelet-derived extracellular vesicles into the field of regenerative medicine. (4) In the future, platelet-derived extracellular vesicles may become a cell-free alternative to platelet-rich plasma in regenerative medicine, but the clinical translation of platelet-derived extracellular vesicles needs to actively search for specific markers to differentiate platelet-derived microparticles from plateletderived exosomes. The mechanism of activator-stimulated platelet-derived extracellular vesicle production, as well as the optimal method of platelet-derived extracellular vesicle collection, the optimal method of storage, the shelf life of the platelet-derived extracellular vesicles, the recommended dosage of plateletderived extracellular vesicles for clinical application, and the optimal clinical indications need to be further investigated. [ABSTRACT FROM AUTHOR]

Abstract Introduction Osteoarthritis (OA) of the knee affects millions of people with sizable socioeconomic burden. Conventional treatment modalities are prioritized, turning to surgical intervention only when they have failed. However, these traditional modalities have shortcomings, only aiming to reduce pain rather than targeting the underlying pathophysiology. Recently, the use of biologics, including autologous peripheral blood-derived orthobiologics (APBOs), has increased and demonstrated great promise for the management of knee OA. Platelet-rich plasma (PRP) is the most widely used APBO, but its efficacy is still uncertain, attributed to lack of standardized formulation protocols, characterization, and patient variables. To overcome the limitations posed by PRP, the use of other APBOs such as platelet lysate (PL) has been considered. This review summarizes the outcomes of clinical studies involving PL to manage OA of the knee. Methods Multiple databases (Scopus, Embase, PubMed, and Web of Science) were searched employing terms “platelet lysate” and “knee osteoarthritis” for articles published in the English language to August 15, 2024, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results Only three clinical studies fulfilled our search and inclusion criteria. Intra-articular injection of three doses of PL injected every 3–4 weeks is safe and efficacious, resulting in statistically significant improvements in different patient-reported outcome measures at 6–12 months follow-up. Conclusion The existing published peer-reviewed literature suggests that intra-articular injection of PL is safe and can decrease pain and increase function in patients with knee OA. Nonetheless, given the dearth of pertinent literature, more adequately powered, multicenter, prospective, non-randomized and randomized controlled studies with extended follow-up are needed to confirm the effectiveness of PL in knee OA. Further comparative studies to help clinicians in choosing the best APBO for knee OA treatment are also warranted.

Abstract Pressure ulcers (PU) are caused by persistent long-term pressure, which compromises the integrity of the epidermis, dermis, and subcutaneous adipose tissue layer by layer, making it difficult to heal. Platelet products such as platelet lysate (PL) can promote tissue regeneration by secreting numerous growth factors based on clinical studies on skin wound healing. However, the components of PL are difficult to retain in wounds. Gelatin methacrylate (GelMA) is a photopolymerizable hydrogel that has lately emerged as a promising material for tissue engineering and regenerative medicine. The PL liquid was extracted, flow cytometrically detected for CD41a markers, and evenly dispersed in the GelMA hydrogel to produce a surplus growth factor hydrogel system (PL@GM). The microstructure of the hydrogel system was observed under a scanning electron microscope, and its sustained release efficiency and biological safety were tested in vitro. Cell viability and migration of human dermal fibroblasts, and tube formation assays of human umbilical vein endothelial cells were applied to evaluate the ability of PL to promote wound healing and regeneration in vitro. Real-time polymerase chain reaction (PCR) and western blot analyses were performed to elucidate the skin regeneration mechanism of PL. We verified PL’s therapeutic effectiveness and histological analysis on the PU model. PL promoted cell viability, migration, wound healing and angiogenesis in vitro. Real-time PCR and western blot indicated PL suppressed inflammation and promoted collagen I synthesis by activating STAT3. PL@GM hydrogel system demonstrated optimal biocompatibility and favorable effects on essential cells for wound healing. PL@GM also significantly stimulated PU healing, skin regeneration, and the formation of subcutaneous collagen and blood vessels. PL@GM could accelerate PU healing by promoting fibroblasts to migrate and secrete collagen and endothelial cells to vascularize. PL@GM promises to be an effective and convenient treatment modality for PU, like chronic wound treatment.

Objective: To create 2-mm diameter multilayer porous tubular scaffolds (PTS) with characteristics that resemble small-diameter native blood vessels in terms of characteristics.Materials and methods. PTS made of polycaprolactone (PCL, MM 80000) with a PCL-made sealing coat/layer with gelatin addition (PCL-gelatin) with a diameter of 2 mm were created by electrospinning (NANON-01A). Bioactive coating was applied to the PTS surface by sequential incubation in solutions of bovine serum albumin, heparin (Hp), and platelet lysate (PL). Cytotoxicity was investigated under conditions of direct contact of PTS with a monolayer of NIH/3T3 mouse fibroblasts. Viability of human umbilical vein endothelial cells (EA.hy926) was evaluated using Live/Dead® Viability/Cytotoxicity Kit. Permeability and blood flow parameters of the PTS implanted in the infrarenal section of the rat aorta were recorded using Doppler imaging.Results. A three-layer PTS construct with an inner diameter of 2 mm was developed. Its inner and outer layers were formed from 0.2 mL of PCL solution, and the middle sealing coat/layer was from 0.5 mL of PCL with addition of 30% (by weight of polymer) gelatin. Introduction of the sealing coat/layer reduced surgical porosity (SP) from 56.2 ± 8.7 mL/(cm2·min) for a single-layer PTS made of pure PCL to 8.9 ± 2.6 mL/(cm2·min) for a three-layer PTS. The resulting PTS demonstrated physicomechanical characteristics similar to those of native blood vessels; it also showed no cytotoxicity. Application of a bioactive coating of Hp and PL allowed for increased in vitro adhesion and proliferation of endothelial cells. The technique of implantation of 10 mm long fragments of three-layer PTS into the infrarenal section of a rat aorta was corrected, thus minimizing blood loss and narrowing the anastomosis site. In an acute experiment, it was proven that the prostheses were patent and that blood flow parameters (systolic and diastolic velocity, resistivity index) were close to the corresponding indicators of native rat aorta.Conclusion. The developed three-layer PTS constructs have low SP and physicomechanical properties close to those of native blood vessels. Bioactive coating improves the in vitro matrix properties of PTS relative to human endothelial cells. At short-term implantation into the aorta of experimental animals, PTS showed no early thrombosis, while blood flow parameters were close to those of native rat aorta. Thus, three-layer PTS with bioactive coating can be used as a scaffold for creation of in situ tissue-engineered construct of a small-diameter blood vessel.

Intra-articular injection-based therapy is often used aside conservative treatment and lifestyle modifications to manage knee osteoarthritis (KO) patients. Conventional injections contain steroids and hyaluronic acid, while more recently multipotential adult stem cell, platelet-rich plasma (PRP), and platelet lysate (PL) injections have been used to promote cartilage regeneration or repair. The aim of the current study is to analyse current evidence on PL injections for the treatment of KO and to determine if these are effective and how these perform compared to other injection regimens. The databases of Scopus, Embase, PubMed, Web of Science, and Cochrane Library were searched on 30 June 2023. Risk of bias was assessed using the SYRCLE tool for animal studies and Cochrane RoB 2 as well as ROBINS-I tool for human studies. Studies were included if these were in English, any year, and regarded animals with osteoarthritis (OA) or human adult patients with OA. In vitro trials and non-adult human studies were excluded. Results on OA symptom stage and severity, and pain were recorded. The research retrieved three human studies (n = 48, n = 25, n = 58) and four animal studies: one rabbit, two studies, and one rat study. PL was found to decrease KO symptoms at follow-up ≤ 1 year with respect to baseline levels and when compared to hyaluronic acid or platelet-rich plasma. Symptoms returned 6 months–1 year after the final administration, with studies showing peak efficacy at approximately 6 months. Animal studies showed clinical improvements, reduction of lameness, and partial effect on the cartilage regeneration of the seven studies, two had a high risk of bias, four were associated to some concerns, and one had low risk. A major source of bias in these studies was the use of questionnaires and scoring that could be subject to interpretation. Overall, PL was well-tolerated and showed efficacy comparable to PRP; when pain control was assessed, it showed similar efficacy compared to hyaluronic acid. These findings may support its use in clinical trials to confirm these initial findings; future research should also focus on the comparison with other non-surgical treatments, on a more detail of the potential regenerative properties, and to optimise the treatment schedule. [ABSTRACT FROM AUTHOR]

Platelet lysate (PL) is investigated as a potential replacement for fetal bovine serum (FBS) in cell culture. However, there is limited research on its impact on the immune profile of equine mesenchymal stromal cells (eMSCs). This study aimed to evaluate the effects of different PL formulations on the proliferative capacity, multipotentiality, and immune profile of equine adipose tissue-derived MSCs (eAD-MSCs). In vitro growth kinetics and trilineage differentiation of eAD-MSCs (n = 7) were assessed under three culture conditions: mediumconcentration PL (MPL), high-concentration PL (HPL), and FBS as a control. The immune profile was evaluated by studying the expression of immunogenic receptors such as MHC I, MHC II, and immunomodulatory molecules IL-6, IL-10, and TNF-α, determined by gene expression, surface marker expression, and cytokine quantification. Both PL formulations, pooled from 5 donors, exhibited 3.3 and 6.5-fold higher platelet counts than baseline plasma for MPL and HPL, respectively. Higher concentrations of TGF-β and PDGF were found in both PL formulations compared to baseline. Furthermore, MPL and HPL subcultures demonstrated proliferative, clonogenic, and multipotent capacities similar to FBS. The immune profile of PL-cultured cells exhibited gene expression levels related to immunogenicity and immunomodulation similar to the reference condition, and the surface antigen presence of MHC II was also similar. However, HPL media exhibited higher IL-6, IL-10, and TNF-α concentrations in the culture supernatant. In conclusion, both PL media contained higher concentrations of growth factors compared to FBS, supporting the in vitro culture of eAD-MSCs with proliferative, clonogenic, and multipotent capacity similar to the reference medium. Nonetheless, PL usage led to a variation in the immunomodulatory cytokine microenvironment, with higher concentrations of IL-6, IL-10, and TNF-α in HPL media compared to MPL and FBS. [ABSTRACT FROM AUTHOR]

Pressure ulcers (PU) are caused by persistent long-term pressure, which compromises the integrity of the epidermis, dermis, and subcutaneous adipose tissue layer by layer, making it difficult to heal. Platelet products such as platelet lysate (PL) can promote tissue regeneration by secreting numerous growth factors based on clinical studies on skin wound healing. However, the components of PL are difficult to retain in wounds. Gelatin methacrylate (GelMA) is a photopolymerizable hydrogel that has lately emerged as a promising material for tissue engineering and regenerative medicine. The PL liquid was extracted, flow cytometrically detected for CD41a markers, and evenly dispersed in the GelMA hydrogel to produce a surplus growth factor hydrogel system (PL@GM). The microstructure of the hydrogel system was observed under a scanning electron microscope, and its sustained release efficiency and biological safety were tested in vitro. Cell viability and migration of human dermal fibroblasts, and tube formation assays of human umbilical vein endothelial cells were applied to evaluate the ability of PL to promote wound healing and regeneration in vitro. Real-time polymerase chain reaction (PCR) and western blot analyses were performed to elucidate the skin regeneration mechanism of PL. We verified PL’s therapeutic effectiveness and histological analysis on the PU model. PL promoted cell viability, migration, wound healing and angiogenesis in vitro. Real-time PCR and western blot indicated PL suppressed inflammation and promoted collagen I synthesis by activating STAT3. PL@GM hydrogel system demonstrated optimal biocompatibility and favorable effects on essential cells for wound healing. PL@GM also significantly stimulated PU healing, skin regeneration, and the formation of subcutaneous collagen and blood vessels. PL@GM could accelerate PU healing by promoting fibroblasts to migrate and secrete collagen and endothelial cells to vascularize. PL@GM promises to be an effective and convenient treatment modality for PU, like chronic wound treatment. [ABSTRACT FROM AUTHOR]

Muscle-derived mesenchymal stromal cells (mdMSCs) hold great promise in regenerative medicine due to their immunomodulatory properties, multipotent differentiation capacity and ease of collection. However, traditional in vitro expansion methods use fetal bovine serum (FBS) and have numerous limitations including ethical concerns, batch-to-batch variability, immunogenicity, xenogenic contamination and regulatory compliance issues. This study investigates the use of 10% equine platelet lysate (ePL) obtained by plasmapheresis as a substitute for FBS in the culture of mdMSCs in innovative 2D and 3D models. Using muscle microbiopsies as the primary cell source in both models showed promising results. Initial investigations indicated that small variations in heparin concentration in 2D cultures strongly influenced medium coagulation with an optimal proliferation observed at final heparin concentrations of 1.44 IU/mL. The two novel models investigated showed that expansion of mdMSCs is achievable. At the end of expansion, the 3D model revealed a higher total number of cells harvested (64.60 ± 5.32 million) compared to the 2D culture (57.20 ± 7.66 million). Trilineage differentiation assays confirmed the multipotency (osteoblasts, chondroblasts and adipocytes) of the mdMSCs generated in both models with no significant difference observed. Immunophenotyping confirmed the expression of the mesenchymal stem cell (MSC) markers CD-90 and CD-44, with low expression of CD-45 and MHCII markers for mdMSCs derived from the two models. The generated mdMSCs also had great immunomodulatory properties. Specific immunological extraction followed by enzymatic detection (SIEFED) analysis demonstrated that mdMSCs from both models inhibited myeloperoxidase (MPO) activity in a strong dose-dependent manner. Moreover, they were also able to reduce reactive oxygen species (ROS) activity, with mdMSCs from the 3D model showing significantly higher dose-dependent inhibition compared to the 2D model. These results highlighted for the first time the feasibility and efficacy of using 10% ePL for mdMSC expansion in novel 2D and 3D approaches and also that mdMSCs have strong immunomodulatory properties that can be exploited to advance the field of regenerative medicine and cell therapy instead of using FBS with all its drawbacks. [ABSTRACT FROM AUTHOR]

Simple Summary: Platelet-rich plasma and related orthobiologics, such as platelet lysates, autologous conditioned serums, and autologous protein solutions, are relatively new regenerative therapies used in the medical management of chronic musculoskeletal disorders in horses. Numerous papers have been published in this area; however, there is no information on the bibliometric impact of these papers in the published veterinary literature. A bibliometric analysis was performed using the bibliometrix R package to evaluate the documents registered in the WOS and Scopus databases from 2000 to 2024. The obtained registers were evaluated considering their overview, sources, authors, documents, words, trending topics, clustering, conceptual structure, and social structure. Frontiers in Veterinary Science, Journal of Equine Veterinary Science, BMC Veterinary Research, and the American Journal of Veterinary Research were the most used sources to publish these papers. Universidad de Caldas, Colorado State University, University of California-Davis, and University of Leipzig were the most productive institutions, while the USA, Brazil, and Colombia had the highest production in this field. The most frequently used keywords were horse, platelet-rich plasma, equine, osteoarthritis, and autologous conditioned serum. The trending topics in this field are platelet lysates and orthobiologics. The collaborative network of authors, institutions, and countries is clustered and isolated in small research groups. (1) Background: There is increasing interest in the use of platelet-rich plasma and related orthobiologics for the treatment of chronic musculoskeletal disorders in horses; however, there is no information on the bibliometric impact of the literature published in this area. (2) Methods: A bibliometric analysis was performed using the bibliometrix R package by analyzing the documents registered in the WOS and Scopus databases from 2000 to 2024. The included registers were evaluated according to the menu of results from the biblioshiny web app (overview, sources, authors, documents, words, trending topics, clustering, conceptual structure, and social structure). (3) Conclusions: The documents produced were mainly published in Frontiers in Veterinary Science, Journal of Equine Veterinary Science, BMC Veterinary Research, and the American Journal of Veterinary Research). The most productive institutions were Universidad de Caldas, Colorado State University, University of California-Davis, and University of Leipzig, and the most productive countries were the USA, Brazil, and Colombia. Horse, platelet-rich plasma, equine, osteoarthritis, and autologous conditioned serum were the most frequently used keywords. The trending topics in this area are platelet lysates and orthobiologics. The collaboration network of authors, institutions, and countries shows an isolated development of individual author networks with modest collaboration between institutions and countries. [ABSTRACT FROM AUTHOR]

The coordinated migration of invasive tumor cells is a complex and dynamic mechanism driven by diverse cellular and molecular events. Unfortunately, the inherent heterogeneity within tumors raises multiple challenges in deciphering key biomarkers and novel therapeutic approaches to prevent tumor metastasis. Here, a microengineered tumor‐on‐a‐chip system incorporating human platelet lysate hydrogels is proposed to recreate the early metastatic process of tumor invasion and drug response. By co‐culturing human bone marrow mesenchymal stem cells with two tumor cell lines with distinct metastatic capability, the developed model can emulate the 3D tumor microarchitecture and inter‐heterogeneity regarding its intrinsic metastatic ability. The recreated microenvironment supports tumor and stromal cell movement, evidencing the synergistic tumor‐stromal cell and cell‐extracellular matrix interactions of an invading tumor. Through gene and protein expression analysis and exometabolomic profiling, this tumor‐on‐a‐chip platform provides evidence for the role of a dynamic environment as a key regulator of tumor metastatic ability. Additionally, the effect of doxorubicin treatment on tumor invasiveness and biomarker profile highlights the suitability of the established models for therapy assessment. Overall, this study presents a tumor‐on‐a‐chip model useful to pursue mechanistic studies on early metastatic events in a fully human‐derived microenvironment, while contributing with fundamental insights into biomolecular profiling. [ABSTRACT FROM AUTHOR]

Background: Platelet lysate is an acellular platelet product containing factors released from secretory granules, including cytokines and growth factors. This study aimed to evaluate different centrifugation methods used to prepare canine platelet lysate with variable content of leukocytes, plasma, and heatsensitive proteins. Methods: Whole blood was collected from six dogs and two double-spin preparation methods were used to generate the platelet-rich plasma with reduced (PRP) and high (L-PRP) concentration of leukocytes. A portion of both methods underwent plasma depletion via centrifugation and platelet lysate was generated via freeze-thaw cycles. A portion of the generated platelet lysate underwent complement inactivation via heat treatment. Growth factors (TGF-ß1, VEGF, TNF-a, PDGF-BB, HGF) were quantified in all different platelet lysate preparations using ELISAs. Results: Both platelet-rich plasma preparations had a 6.7-fold increase in platelet concentration. White blood cell (WBC) concentration compared to whole blood increased 1.2-fold times in PRP and 1.9-fold times in L-PRP. Negligible concentrations of platelets, WBC, and hematocrit were identified in all lysate groups. Statistically significant differences were identified for PDGF, VEGF, and TNF-a, and not for TGF-ß or HGF. No growth factor differences were noted between centrifugation methods. PDGF was significantly higher in platelet lysate that was plasma depleted. VEGF was significantly higher in heattreated lysate groups. TNF-a concentrations were overall very low, though were noted to significantly increase following plasma depletion. Conclusion: These results support that growth factors and cytokine release can be affected by the platelet lysate preparation and processing. [ABSTRACT FROM AUTHOR]

BACKGROUND: The research of dental stem cells in the fields of regenerative medicine and tissue engineering has been deepening, bringing hope for the repair of tooth-related tissues and the treatment of systemic diseases. However, there is a lack of systematic research and analysis on the biological characteristics of dental stem cells in different age groups. OBJECTIVE: To explore the biological characteristics of the human deciduous tooth and permanent tooth pulp stem cells cultured in umbilical cord blood platelet lysate to provide a reliable basis for human platelet lysates to replace fetal bovine serum. METHODS: The pulp tissues of deciduous teeth, juvenile permanent teeth and adult permanent teeth were taken out and cultured in DMEM/F-12 medium supplemented with 10% fetal bovine serum or different concentrations (5%, 10% and 15%) of human platelet lysates. Cell proliferation in the four groups was detected by cytometry. The optimal concentration of human platelet lysates was selected for subsequent experiments. Under the optimal concentration of human platelet lysates, human deciduous tooth and juvenile and adult permanent tooth pulp stem cells were cultured in vitro. The cell growth status was observed under the microscope. The specific antigen on the cell surface was detected by flow cytometry. The cell proliferation ability was tested by the cell counting method and CCK-8 assay. The cell differentiation ability in vitro was observed by a three-line differentiation assay. RESULTS AND CONCLUSION: (1) The cell proliferation rate of the 10% human platelet lysate group was the highest. (2) In all three groups, fusiform fibrous cells grew and expanded from around the tissue block. There was no significant difference between deciduous teeth and juvenile permanent tooth cells, but the adult permanent tooth cells were larger than the deciduous and juvenile permanent tooth cells of the same generation. (3) The results of flow cytometry showed that deciduous teeth, juvenile permanent teeth and adult permanent teeth conformed to the phenotypic characteristics of mesenchymal stem cells. (4) The proliferative capacity of adult permanent dental pulp stem cells was significantly lower than those of deciduous teeth and juvenile permanent dental pulp stem cells (P < 0.01). (5) mRNA expressions of osteoblast-related genes alkaline phosphatase and bone morphogenetic protein 2, lipoprotein lipase and peroxisome proliferator-activated receptor γ2, mRNA expressions of chondroblast related gene type II collagen α1 and cartilage oligomeric matrix protein in adult pulp stem cells of permanent teeth were significantly lower than those of deciduous teeth and juvenile permanent teeth pulp stem cells (P < 0.01). (6) Compared with adult dental pulp stem cells, human deciduous teeth and juvenile permanent teeth dental pulp stem cells have the stronger proliferative capacity and multidirectional differentiation potential, and are more suitable for clinical research and disease treatment. [ABSTRACT FROM AUTHOR]

Background: Macrophages are innate immune cells that display remarkable phenotypic heterogeneity and functional plasticity. Due to their involvement in the pathogenesis of several human conditions, macrophages are considered to be an attractive therapeutic target. In line with this, platelet derivatives have been successfully applied in many medical fields and as active participants in innate immunity, cooperation between platelets and macrophages is essential. In this context, the aim of this review is to compile the current evidence regarding the effects of platelet derivatives on the phenotype and functions of macrophages to identify the advantages and shortcomings for feasible future clinical applications. Methods: A total of 669 articles were identified during the systematic literature search performed in PubMed and Web of Science databases. Results: A total of 27 articles met the inclusion criteria. Based on published findings, platelet derivatives may play an important role in inducing a dynamic M1/M2 balance and promoting a timely M1-M2 shift. However, the differences in procedures regarding platelet derivatives and macrophages polarization and the occasional lack of information, makes reproducibility and comparison of results extremely challenging. Furthermore, understanding the differences between human macrophages and those derived from animal models, and taking into account the peculiarities of tissue resident macrophages and their ontogeny seem essential for the design of new therapeutic strategies. Conclusion: Research on the combination of macrophages and platelet derivatives provides relevant information on the function and mechanisms of the immune response. [ABSTRACT FROM AUTHOR]

IntroductionPlatelet lysate (PL) demonstrates antimicrobial and anti-inflammatory properties offering potential for treatment of bacterial pneumonia in horses. It remains unknown whether nebulization is suitable for PL administration in horses. This pilot study characterized particle size and flow rate of pooled equine PL (single preparation) nebulized using an equine-specific nebulizer (Flexivent®).MethodsProtein composition and antimicrobial activity were compared before and after nebulization. Protein composition was evaluated according to growth factor, antimicrobial peptide and cytokine concentrations and proteomic analysis. To evaluate antimicrobial activity, bacterial growth inhibition [maximum growth (μmax); carrying capacity (K)] were determined for E. coli, Streptococcus equi subsp zooepidemicus and Rhodococcus equi (WT and MDR) using pre- and post-nebulized PL concentrations of 50%.ResultsFlow rate and median particle size were 0.8 ml/min and 4.991 μm with 52% of particles ≤ 5 μm. Differences in PL protein composition were detected with nebulization. For E. coli and S. zooepidemicus, nebulization did not alter effect of PL on growth parameters. PL treatments decreased K for S. zooepidemicus (p = 0.009) compared to BHI. For R. equi K was increased post- vs. pre-nebulization (WT and MDR) and μmax increased pre- vs, post-nebulization (MDR). PL treatments increased K and μmax for MDR R. equi and μmax for WT R. equi compared to BHI (p ≤ 0.05).ConclusionNebulization of PL in vitro is technically feasible. The results of this study support further investigation to better characterize the effect of nebulization on PL and its suitability for nebulization in horses.

Human umbilical cord mesenchymal stem cells (HUC-MSCs) and platelet lysate (PL) shows potential of wound healing. However, MSCs in combination with PL for wound healing is still lacking. In this study, we presented high glucose cultured wound related cells to mimic diabetic chronic ulcers (DCU) cells, wound healing indicators and the TGFβ/Smad signaling pathway were detected by PL cultured HUC-MSC supernatant (MSC-Sp) in vitro. In vivo study, diabetes was induced in pigs feeding a high-energy diet and multiple injections of streptozotocin (125 mg/kg). Chronic wounds were created on both sides of the backs of seven pigs by surgical creation and foreign body compression for eight weeks before treatment. The wounds were treated with saline control (N = 11), PL (N = 11), HUC- MSCs (N = 18, 6 × 106/mL/cm2), and PL + HUC-MSCs (N = 18, 6 × 106/mL/cm2) respectively. Tissue samples were collected to observe new collagen, neovascularization, wound healing factors, and the TGFβ/Smad signaling pathway. The resulting PL-cultured MSC-Sp promoted the proliferation of keratinocytes, fibroblasts, and vascular endothelial cells and inhibited the TGFβ1/TGFβ3 ratio, upregulated VEGF-α and PDGF-BB production by keratinocytes and fibroblasts, and downregulated the expression of CD86, IL-6, and TNF-α in RAW264.7 cells. PL + HUC-MSCs had the best wound healing rate in vivo, and promoted collagen formation, neovascularization, and inflammation, regulated the balance between IL-6/TGFβ1 and IL-6/Arg-1 and upregulated the expression of VEGF-α and TGFβ1. In summary, PL + HUC-MSCs had a better wound healing effect than HUC-MSCs or PL treatment alone by regulating the IL-6/Arg-1 and IL-6/TGFβ1 balance and upregulating TGFβ1, VEGF-α, Col1, and α-SMA.

Multipotent mesenchymal stromal cells (MSC) play an increasing role in the treatment of immune-mediated diseases and inflammatory processes. They regulate immune cells via cell-cell contacts and by secreting various anti-inflammatory molecules but are in turn influenced by many factors such as cytokines. For MSC culture, platelet lysate (PL), which contains a variety of cytokines, is a promising alternative to fetal bovine serum (FBS). We aimed to analyze if PL with its cytokines improves MSC immunoregulatory characteristics, with the perspective that PL could be useful for priming the MSC prior to therapeutic application. MSC, activated peripheral blood mononuclear cells (PBMC) and indirect co-cultures of both were cultivated in media supplemented with either PL, FBS, FBS+INF-g or FBS+IL-10. After incubation, cytokine concentrations were measured in supernatants and control media. MSC were analyzed regarding their expression of immunoregulatory genes and PBMC regarding their proliferation and percentage of FoxP3+ cells. Cytokines, particularly IFN-g and IL-10, remained at high levels in PL control medium without cells but decreased in cytokine-supplemented control FBS media without cells during incubation. PBMC released IFN-g and IL-10 in various culture conditions. MSC alone only released IFN-g and overall, cytokine levels in media were lowest when MSC were cultured alone. Stimulation of MSC either by PBMC or by PL resulted in an altered expression of immunoregulatory genes. In co-culture with PBMC, the MSC gene expression of COX2, TNFAIP6, IDO1, CXCR4 and MHC2 was upregulated and VCAM1 was downregulated. In the presence of PL, COX2, TNFAIP6, VCAM1, CXCR4 and HIF1A were upregulated. Functionally, while no consistent changes were found regarding the percentage of FoxP3+ cells, MSC decreased PBMC proliferation in all media, with the strongest effect in FBS media supplemented with IL-10 or IFN-g. This study provides further evidence that PL supports MSC functionality, including their immunoregulatory mechanisms. The results justify to investigate functional effects of MSC cultured in PL-supplemented medium on different types of immune cells in more detail. [ABSTRACT FROM AUTHOR]

Platelet lysate (PL) is investigated as a potential replacement for fetal bovine serum (FBS) in cell culture. However, there is limited research on its impact on the immune profile of equine mesenchymal stromal cells (eMSCs). This study aimed to evaluate the effects of different PL formulations on the proliferative capacity, multipotentiality, and immune profile of equine adipose tissue-derived MSCs (eAD-MSCs). In vitro growth kinetics and trilineage differentiation of eAD-MSCs (n = 7) were assessed under three culture conditions: medium-concentration PL (MPL), high-concentration PL (HPL), and FBS as a control. The immune profile was evaluated by studying the expression of immunogenic receptors such as MHC I, MHC II, and immunomodulatory molecules IL-6, IL-10, and TNF-α, determined by gene expression, surface marker expression, and cytokine quantification. Both PL formulations, pooled from 5 donors, exhibited 3.3 and 6.5-fold higher platelet counts than baseline plasma for MPL and HPL, respectively. Higher concentrations of TGF-β and PDGF were found in both PL formulations compared to baseline. Furthermore, MPL and HPL subcultures demonstrated proliferative, clonogenic, and multipotent capacities similar to FBS. The immune profile of PL-cultured cells exhibited gene expression levels related to immunogenicity and immunomodulation similar to the reference condition, and the surface antigen presence of MHC II was also similar. However, HPL media exhibited higher IL-6, IL-10, and TNF-α concentrations in the culture supernatant. In conclusion, both PL media contained higher concentrations of growth factors compared to FBS, supporting the in vitro culture of eAD-MSCs with proliferative, clonogenic, and multipotent capacity similar to the reference medium. Nonetheless, PL usage led to a variation in the immunomodulatory cytokine microenvironment, with higher concentrations of IL-6, IL-10, and TNF-α in HPL media compared to MPL and FBS.

BackgroundPlatelet lysate is an acellular platelet product containing factors released from secretory granules, including cytokines and growth factors. This study aimed to evaluate different centrifugation methods used to prepare canine platelet lysate with variable content of leukocytes, plasma, and heat-sensitive proteins.MethodsWhole blood was collected from six dogs and two double-spin preparation methods were used to generate the platelet-rich plasma with reduced (PRP) and high (L-PRP) concentration of leukocytes. A portion of both methods underwent plasma depletion via centrifugation and platelet lysate was generated via freeze–thaw cycles. A portion of the generated platelet lysate underwent complement inactivation via heat treatment. Growth factors (TGF-β1, VEGF, TNF-α, PDGF-BB, HGF) were quantified in all different platelet lysate preparations using ELISAs.ResultsBoth platelet-rich plasma preparations had a 6.7-fold increase in platelet concentration. White blood cell (WBC) concentration compared to whole blood increased 1.2-fold times in PRP and 1.9-fold times in L-PRP. Negligible concentrations of platelets, WBC, and hematocrit were identified in all lysate groups. Statistically significant differences were identified for PDGF, VEGF, and TNF-α, and not for TGF-β or HGF. No growth factor differences were noted between centrifugation methods. PDGF was significantly higher in platelet lysate that was plasma depleted. VEGF was significantly higher in heat-treated lysate groups. TNF-α concentrations were overall very low, though were noted to significantly increase following plasma depletion.ConclusionThese results support that growth factors and cytokine release can be affected by the platelet lysate preparation and processing.

Objective: MSCs and Platelet-Rich Plasma are the main focus in the study of new regenerative treatments aimed to reverse Osteoarthritis (OA). However, extracellular vesicles (EVs) present several advantages to cell-based treatments. Thus, the aim of this study was to compare and evaluate the regenerative potential of MSC-derived EVs (cEVs) and platelet-derived EVs (pEVs) in an OA cartilage rat model. Design: OA in vivo model was established through injection of 6 mg MIA in the rat knee joints. After 14 and 21 days, OA knee joints were treated with 1 × 1010 particles of pEVs or cEVs. At day 28, the animals were sacrificed, plasma was collected to quantify CTX-II and knee joints were excised to be evaluated by Cone Beam Computed Tomography (CBCT). After decalcification, histology was used to determine the OARSI score and to visualize collagen and glycosaminoglycan content. Results: pEVs and cEVs samples did not show significant differences per se but they did in terms of regenerative effects on OA knee joints. pEVs-treated knee joints showed better subchondral bone integrity in CT-analysed parameters when compared to cEVs or OA group, showing similar values to the healthy control group. Moreover, OARSI score indicated that pEVs showed a greater OA reversion in knee joints, especially in female rats, and so indicated the analysed histological images. Conclusions: pEVs are proposed as a viable regeneration treatment for OA since they are not only capable of exerting their regenerative potential on osteoarthritic cartilage, but also outperform cEVs in terms of efficacy, particularly in females. Significance statement: Osteoarthritis (OA) is one of the most age-related diseases. It is estimated that 500 million people suffer from OA worldwide, representing the principal cause of chronic disability in adults. In the present study we evaluated the therapeutic effect of extracellular vesicles (EVs) from different sources (platelet lysate and human umbilical cord mesenchymal stromal cells) in an in vivo rat model. Our results demonstrate that platelet-derived EVs (pEVs) induce an OA reversion in knee joints, thus evidencing the therapeutic potential of pEVs as cell-free regenerative agents for OA treatment. The translational potential of this article: Platelet-derived extracellular vesicles (pEVs) offer a promising cell-free therapy option for OA treatment. Their production could be easily standardized and reproduced without extensive platelet harvesting and amplification, thus paving the way for their clinical translation.

This document is an editorial published in the journal Frontiers in Veterinary Science. The editorial discusses the links between regenerative medicine and immunotherapy and how cellular therapies can modulate immune responses for improved outcomes. The authors highlight the advancements in veterinary regenerative medicine and the various treatment options available. They emphasize the need for further research to understand the mechanisms of action and to guide treatment selection. The editorial also includes summaries of seven articles that explore different therapeutic strategies and their impact on immune responses. Overall, the editorial provides valuable insights for veterinary clinicians and researchers in the field of regenerative therapies. [Extracted from the article]

Background/Objectives: Chronic skin wounds (CSWs) are a worldwide healthcare problem with relevant impacts on both patients and healthcare systems. In this context, innovative treatments are needed to improve tissue repair and patient recovery and quality of life. Cord blood platelet lysate (CB-PL) holds great promise in CSW treatment thanks to its high growth factors and signal molecule content. In this work, thermo-sensitive hydrogels based on an amphiphilic poly(ether urethane) (PEU) were developed as CB-PL carriers for CSW treatment. Methods: A Poloxamer 407®-based PEU was solubilized in aqueous medium (10 and 15% w/v) and added with CB-PL at a final concentration of 20% v/v. Hydrogels were characterized for their gelation potential, rheological properties, and swelling/dissolution behavior in a watery environment. CB-PL release was also tested, and the bioactivity of released CB-PL was evaluated through cell viability, proliferation, and migration assays. Results: PEU aqueous solutions with concentrations in the range 10–15% w/v exhibited quick (within a few minutes) sol-to-gel transition at around 30–37 °C and rheological properties modulated by the PEU concentration. Moreover, CB-PL loading within the gels did not affect the overall gel properties. Stability in aqueous media was dependent on the PEU concentration, and payload release was completed between 7 and 14 days depending on the polymer content. The CB-PL-loaded hydrogels also showed biocompatibility and released CB-PL induced keratinocyte migration and proliferation, with scratch wound recovery similar to the positive control (i.e., CB-PL alone). Conclusions: The developed hydrogels represent promising tools for CSW treatment, with tunable gelation properties and residence time and the ability to encapsulate and deliver active biomolecules with sustained and controlled kinetics.

In the last few decades, mesenchymal stem cells (MSCs)-based regenerative therapies in clinical applications have gradually become a hot topic due to their long-term self-renewal and multilineage differentiation ability. In this scenario, placenta (p) has been considered as a good source of MSCs. As a tissue of fetal origin with abundant number of stem cells compared to other sources, their non-invasive acquisition, strong immunosuppression, and lack of ethical concerns make placenta an indispensable source of MSC in stem cell research and therapy. The mesenchymal stem cells were derived from human term placenta (p-MSCs) in xenofree condition using platelet lysate (PL) as a suitable alternative to fetal bovine serum (FBS). Upon isolation, p-MSCs showed plastic adherence with spindle-shaped, fibroblast-like morphology under microscope. p-MSCs flourished well in PL-containing media. Immunophenotyping showed classical MSC markers (> 90%) and lack expression of hematopoietic and HLA-DR (< 1%). Surprisingly, differentiation study showed differentiation of p-MSCs to mature adipocytes in both induced cells and control (spontaneous differentiation), as observed via oil red staining. This is in line with gene expression data where both control and induced cells were positive for visfatin and leptin. Thus, we propose that p-MSCs can be used for clinical applications in the treatment of various chronic and degenerative diseases. [ABSTRACT FROM AUTHOR]

Background: This study was conducted to examine the hypothesis that umbilical cord blood platelet lysate (UCB-PL) gel has a significant impact on the healing rate of DFU. Μethods: In this open-labeled, randomized controlled trial, 110 patients were randomized to treatment with UCB-PL gel (UCB-PL group, n = 52) every three days for one month or dressing with normal saline (control group, n = 58). All participants were followed up for 20 weeks post treatment. Ulcer surface area was assessed with the imitoMeasure application at two, four, and six weeks, and two, four and six months. This study's main outcome was the reduction in ulcer size over the six-month study period. Results: The mean ulcer area at baseline was 4.1 cm2 in the UCB-PL group and 1.7 cm2 in the control group. At six months post treatment, patients on the UCB-PL treatment displayed a significant reduction in ulcer size compared to baseline 0.12 (0–8.16) in contrast to a more modest change in the control group 1.05 (0–24.7). The ulcer area was decreased at the end of the study in 40 patients (97.6%) in the UCB-PL group and 27 (73%) in the control group (Fisher's p = 0.002). Conclusions: The application of UCB-PL gel in DFU resulted in a significant reduction in ulcer size compared to regular saline dressing. [ABSTRACT FROM AUTHOR]

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

Platelet transfusion has various challenges, and platelet-derived extracellular vesicles have been reported to have more significant procoagulant activity than platelets themselves. Furthermore, platelet products derived from platelet-rich plasma and platelet lysates (PLs) have gained attention for their physiological activity and potential role as drug delivery vehicles owing to the properties of their membranes. We aimed to investigate the characteristics of the fractions isolated through ultracentrifugation from mouse-washed PLs and assess the potential clinical applications of these fractions as a therapeutic approach for bleeding conditions. We prepared PLs from C57BL/6 mouse-washed platelets and isolated three different fractions (20K-vesicles, 100K-vesicles, and PLwo-vesicles) using ultracentrifugation. There was a notable difference in particle size distribution between 20K-vesicles and 100K-vesicles, particularly in terms of the most frequent diameter. The 20K-vesicles exhibited procoagulant activity with concentration dependence, whereas PLwo-vesicles exhibited anticoagulant activity. PLwo-vesicles did not exhibit thrombin generation capacity, and the addition of PLwo-vesicles to Microparticle Free Plasma extended the time to initiate thrombin generation by 20K-vesicles and decreased the peak thrombin value. In a tail-snip bleeding assay, pre-administration of 20K-vesicles significantly shortened bleeding time. PL-derived 20K-vesicles exhibited highly potent procoagulant activity, making them potential alternatives to platelet transfusion. [ABSTRACT FROM AUTHOR]

Background: More understanding of the physiological needs of the embryo during its growth from the zygote to the blastocyst stage, as well as the composition of the uterine andfallopian tubal secretions, has led to the development of single-step or sequential culture media. Objectives: The present study aimed to investigate the utilization of mCR2aa culture medium as a sequential culture medium for embryo development, supplemented with platelet lysate (PL) to decrease the concentration of fetal bovine serum (FBS) in the embryo culture medium. Methods: After maturation and fertilization of sheep oocytes obtained from a slaughterhouse, potential zygotes were cultured in mCR2aa medium without FBS for two days (C1, 1 - 3 days of culture). In the second two days of culture (C2, 3 - 5 days of culture), 2.5% or 5% of FBS and 5% or 10% of PL were used. In the remaining days of culture (C3, 5 - 9 days of culture), 2.5%, 5%, or 10% of FBS, and 0%, 2.5%, 5%, or 10% of PL were used. These percentages were compared to the commercial BO-IVC™ medium and mCR2aa medium, both of which contained 10% of FBS. Results: No significant difference was observed in the number of produced blastocysts between different treatments and the control. However, the number of hatched blastocysts in BO-IVC™, as a single-step culture medium, significantly differed from that of the other treatments. The number of hatched blastocysts in the sequential culture medium was higher in media supplemented with 2.5% FBS and 10% PL in the C2 mCR2aa medium, and 2.5% FBS without PL in the C3 mCR2aa medium, but no significant difference was observed in other treatments. However, increasing the concentration of FBS and PL in the C3 mCR2aa medium significantly decreased the number of hatched blastocysts. Conclusions: An increase in the percentage of PL to 10% necessitated a decrease in FBS to 2.5% in the C2 mCR2aa medium, while PL in the C3 mCR2aa medium was not required in the presence of 2.5% FBS. [ABSTRACT FROM AUTHOR]

Human platelet lysate (hPL) is a supplement for cell culture media that can be derived from platelet concentrates. As not‐for‐profit blood establishments, we endorse the evolution of maximally exploiting the potential of donated blood and its derived components, including platelets. The decision to use platelet concentrates to supply hPL as a cell culture supplement should align with the principles and values that blood establishments hold towards the use of donated blood components in transfusion. As a consequence, questions on ethics, practical standardization of hPL production and logistics as well as on assuring hPL quality and safety need careful consideration. We therefore propose an opinion on some of these matters based on available literature and on discussions within the proceedings of the Working Group on Innovation and New Products of the European Blood Alliance. In addition, we propose collaboration among European blood establishments to streamline efforts of hPL supply to maximize the potential of hPL and its application in the wider field of medicine. [ABSTRACT FROM AUTHOR]

BackgroundMacrophages are innate immune cells that display remarkable phenotypic heterogeneity and functional plasticity. Due to their involvement in the pathogenesis of several human conditions, macrophages are considered to be an attractive therapeutic target. In line with this, platelet derivatives have been successfully applied in many medical fields and as active participants in innate immunity, cooperation between platelets and macrophages is essential. In this context, the aim of this review is to compile the current evidence regarding the effects of platelet derivatives on the phenotype and functions of macrophages to identify the advantages and shortcomings for feasible future clinical applications.MethodsA total of 669 articles were identified during the systematic literature search performed in PubMed and Web of Science databases.ResultsA total of 27 articles met the inclusion criteria. Based on published findings, platelet derivatives may play an important role in inducing a dynamic M1/M2 balance and promoting a timely M1-M2 shift. However, the differences in procedures regarding platelet derivatives and macrophages polarization and the occasional lack of information, makes reproducibility and comparison of results extremely challenging. Furthermore, understanding the differences between human macrophages and those derived from animal models, and taking into account the peculiarities of tissue resident macrophages and their ontogeny seem essential for the design of new therapeutic strategies.ConclusionResearch on the combination of macrophages and platelet derivatives provides relevant information on the function and mechanisms of the immune response.

Multipotent mesenchymal stromal cells (MSC) play an increasing role in the treatment of immune-mediated diseases and inflammatory processes. They regulate immune cells via cell-cell contacts and by secreting various anti-inflammatory molecules but are in turn influenced by many factors such as cytokines. For MSC culture, platelet lysate (PL), which contains a variety of cytokines, is a promising alternative to fetal bovine serum (FBS). We aimed to analyze if PL with its cytokines improves MSC immunoregulatory characteristics, with the perspective that PL could be useful for priming the MSC prior to therapeutic application. MSC, activated peripheral blood mononuclear cells (PBMC) and indirect co-cultures of both were cultivated in media supplemented with either PL, FBS, FBS+INF-γ or FBS+IL-10. After incubation, cytokine concentrations were measured in supernatants and control media. MSC were analyzed regarding their expression of immunoregulatory genes and PBMC regarding their proliferation and percentage of FoxP3+ cells. Cytokines, particularly IFN-γ and IL-10, remained at high levels in PL control medium without cells but decreased in cytokine-supplemented control FBS media without cells during incubation. PBMC released IFN-γ and IL-10 in various culture conditions. MSC alone only released IFN-γ and overall, cytokine levels in media were lowest when MSC were cultured alone. Stimulation of MSC either by PBMC or by PL resulted in an altered expression of immunoregulatory genes. In co-culture with PBMC, the MSC gene expression of COX2, TNFAIP6, IDO1, CXCR4 and MHC2 was upregulated and VCAM1 was downregulated. In the presence of PL, COX2, TNFAIP6, VCAM1, CXCR4 and HIF1A were upregulated. Functionally, while no consistent changes were found regarding the percentage of FoxP3+ cells, MSC decreased PBMC proliferation in all media, with the strongest effect in FBS media supplemented with IL-10 or IFN-γ. This study provides further evidence that PL supports MSC functionality, including their immunoregulatory mechanisms. The results justify to investigate functional effects of MSC cultured in PL-supplemented medium on different types of immune cells in more detail.

Purpose: to compare the effectiveness of conventional preserved amnion and amnion saturated with platelet-rich (PRP) plasma lysate for the treatment of persistent corneal erosions (PCE) after high-risk keratoplasty.Materials and methods. 40 patients with persistent corneal erosions after high-risk penetrating keratoplasty, followed up for 12 months, were divided into two clinical groups of 20 people each. The main group of patients, aged 34 to 84, received Flexamer amniotic membrane + PRP lysate, while the comparison group, aged 41 to 80, received Flexamer amniotic membrane only. Amniotic membrane coating was used in persistent corneal erosions of penetrating keratoplasty after unsuccessful conservative treatment. The amnion was sewn 2 mm from the limb with a continuous suture and covered with a soft contact lens. As a source of platelets, we used the blood of healthy volunteers, from which platelet-rich plasma with platelet concentration of over 1000 thousand/µl was taken, which was then frozen at -40 °C and defrosted at 0…4 °C to obtain PRP lysate. The criteria for evaluating the effectiveness of both groups were the times of epithelialization, the number of amniotic membrane coatings, and the number of preserved transplants at the end of the follow-up.Results. Lyophilized amniotic membrane saturated with autologous PRP lysate growth factors was shown to be biocompatible. It was found to be safe for the patients, to reduce the epithelialization time, to reduce the number of operations required to cover the PÑE with the amnion, and to increase the likelihood of successful transparent and translucent engraftment of a penetrating keratograft.Conclusion. The use of a lyophilized amniotic membrane enriched with growth factors of autologous PRP lysate is a promising method for the treatment of PCE of the penetrating corneal graft after high-risk keratoplasty.

Aims: Extracellular vesicles (EVs) are nanoparticles secreted by all cells, enriched in proteins, lipids, and nucleic acids related to cell-to-cell communication and vital components of cell-based therapies. Mesenchymal stromal cell (MSC)-derived EVs have been studied as an alternative for osteoarthritis (OA) treatment. However, their clinical translation is hindered by industrial and regulatory challenges. In contrast, platelet-derived EVs might reach clinics faster since platelet concentrates, such as platelet lysates (PL), are already used in therapeutics. Hence, we aimed to test the therapeutic potential of PL-derived extracellular vesicles (pEVs) as a new treatment for OA, which is a degenerative joint disease of articular cartilage and does not have any curative or regenerative treatment, by comparing its effects to those of human umbilical cord MSC-derived EVs (cEVs) on an ex vivo OA-induced model using human cartilage explants. Methods: pEVs and cEVs were isolated by size exclusion chromatography (SEC) and physically characterized by nanoparticle tracking analysis (NTA), protein content, and purity. OA conditions were induced in human cartilage explants (10 ng/ml oncostatin M and 2 ng/ml tumour necrosis factor alpha (TNFα)) and treated with 1 × 109 particles of pEVs or cEVs for 14 days. Then, DNA, glycosaminoglycans (GAG), and collagen content were quantified, and a histological study was performed. EV uptake was monitored using PKH26 labelled EVs. Results: Significantly higher content of DNA and collagen was observed for the pEV-treated group compared to control and cEV groups. No differences were found in GAG quantification nor in EVs uptake within any treated group. Conclusion: In conclusion, pEVs showed better performance than cEVs in our in vitro OA model. Although further studies are needed, pEVs are shown as a potential alternative to cEVs for cell-free regenerative medicine. Cite this article: Bone Joint Res 2023;12(10):667–676.

(1) Background: There is increasing interest in the use of platelet-rich plasma and related orthobiologics for the treatment of chronic musculoskeletal disorders in horses; however, there is no information on the bibliometric impact of the literature published in this area. (2) Methods: A bibliometric analysis was performed using the bibliometrix R package by analyzing the documents registered in the WOS and Scopus databases from 2000 to 2024. The included registers were evaluated according to the menu of results from the biblioshiny web app (overview, sources, authors, documents, words, trending topics, clustering, conceptual structure, and social structure). (3) Conclusions: The documents produced were mainly published in Frontiers in Veterinary Science, Journal of Equine Veterinary Science, BMC Veterinary Research, and the American Journal of Veterinary Research). The most productive institutions were Universidad de Caldas, Colorado State University, University of California-Davis, and University of Leipzig, and the most productive countries were the USA, Brazil, and Colombia. Horse, platelet-rich plasma, equine, osteoarthritis, and autologous conditioned serum were the most frequently used keywords. The trending topics in this area are platelet lysates and orthobiologics. The collaboration network of authors, institutions, and countries shows an isolated development of individual author networks with modest collaboration between institutions and countries.

Muscle-derived mesenchymal stromal cells (mdMSCs) hold great promise in regenerative medicine due to their immunomodulatory properties, multipotent differentiation capacity and ease of collection. However, traditional in vitro expansion methods use fetal bovine serum (FBS) and have numerous limitations including ethical concerns, batch-to-batch variability, immunogenicity, xenogenic contamination and regulatory compliance issues. This study investigates the use of 10% equine platelet lysate (ePL) obtained by plasmapheresis as a substitute for FBS in the culture of mdMSCs in innovative 2D and 3D models. Using muscle microbiopsies as the primary cell source in both models showed promising results. Initial investigations indicated that small variations in heparin concentration in 2D cultures strongly influenced medium coagulation with an optimal proliferation observed at final heparin concentrations of 1.44 IU/mL. The two novel models investigated showed that expansion of mdMSCs is achievable. At the end of expansion, the 3D model revealed a higher total number of cells harvested (64.60 ± 5.32 million) compared to the 2D culture (57.20 ± 7.66 million). Trilineage differentiation assays confirmed the multipotency (osteoblasts, chondroblasts and adipocytes) of the mdMSCs generated in both models with no significant difference observed. Immunophenotyping confirmed the expression of the mesenchymal stem cell (MSC) markers CD-90 and CD-44, with low expression of CD-45 and MHCII markers for mdMSCs derived from the two models. The generated mdMSCs also had great immunomodulatory properties. Specific immunological extraction followed by enzymatic detection (SIEFED) analysis demonstrated that mdMSCs from both models inhibited myeloperoxidase (MPO) activity in a strong dose-dependent manner. Moreover, they were also able to reduce reactive oxygen species (ROS) activity, with mdMSCs from the 3D model showing significantly higher dose-dependent inhibition compared to the 2D model. These results highlighted for the first time the feasibility and efficacy of using 10% ePL for mdMSC expansion in novel 2D and 3D approaches and also that mdMSCs have strong immunomodulatory properties that can be exploited to advance the field of regenerative medicine and cell therapy instead of using FBS with all its drawbacks.

Abstract Background Induced pluripotent stem cells (iPS) can be generated from various somatic cells and can subsequently be differentiated to multiple cell types of the body. This makes them highly promising for cellular therapy in regenerative medicine. However, to facilitate their clinical use and to ensure safety, iPS culturing protocols must be compliant with good manufacturing practice guidelines and devoid of xenogenic products. Therefore, we aimed to compare the efficiency of using humanized culture conditions, specifically human platelet lysate to fetal bovine serum, for iPS generation from different sources, and to evaluate their stemness. Methods iPS were generated via a platelet lysate or fetal bovine serum-based culturing protocol from matched dermal, buccal and gingival human fibroblasts, isolated from healthy donors (n = 2) after informed consent, via episomal plasmid transfection. Pluripotency, genotype and phenotype of iPS, generated by both protocols, were then assessed by various methods. Results More attempts were generally required to successfully reprogram xeno-free fibroblasts to iPS, as compared to xenogenic cultured fibroblasts. Furthermore, oral fibroblasts generally required more attempts for successful iPS generation as opposed to dermal fibroblasts. Morphologically, all iPS generated from fibroblasts formed tight colonies surrounded by a reflective “whitish” outer rim, typical for iPS. They also expressed pluripotency markers at both gene (SOX2, OCT4, NANOG) and protein level (SOX2, OCT4). Upon stimulation, all iPS showed ability to differentiate into the three primary germ layers via expression of lineage-specific markers for mesoderm (MESP1, OSR1, HOPX), endoderm (GATA4) and ectoderm (PAX6, RAX). Genome analysis revealed several amplifications and deletions within the chromosomes of each iPS type. Conclusions The xeno-free protocol had a lower reprogramming efficiency compared to the standard xenogenic protocol. The oral fibroblasts generally proved to be more difficult to reprogram than dermal fibroblasts. Xeno-free dermal, buccal and gingival fibroblasts can successfully generate iPS with a comparable genotype/phenotype to their xenogenic counterparts.

The most prevalent type of joint illness is osteoarthritis, also known as OA. The inflammation of the joint is strongly linked to both the beginning and the progression of osteoarthritis. The use of hydrogels as an OA treatment has the potential to go beyond the administration of anti-inflammatory components to have an inherent immunomodulatory role. Platelet lysate (PL) contains a cocktail of growth factors that actively participates in cartilage repair. Moreover, cerium oxide-nanoparticles (CeO2-NPs) have been broadly studied owing to their powerful antioxidant properties and potential preventive and therapeutic effects against chronic diseases. The current study was designed to determine the effect and mechanism of injectable hyaluronic acid (HA) hydrogel loaded with PL and CeO2-NPs on OA. The results showed that the obtained PL and synthesized CeO2-NPs were effectively incorporated into HA hydrogel and the resultant hydrogel was injectable and have a porous micro structure with interconnected pores. The biological evaluation by qPCR revealed that the fabricated hydrogel exhibited a significantly increased expression of Col2 and Aggrecan (TNF-α-suppressed anabolic molecules) and decreased expression of Col10, Mmp13, Adamts5, and Adamts9 (TNF-α-activated catabolic molecules). Also, ELISA results confirmed this potent antioxidant activity of hydrogel and also increased the growth of chondrocytes over the culturing period.

Human umbilical cord–derived mesenchymal stromal cells (hUC-MSCs) are increasingly used in research and therapy. To obtain hUC-MSCs, a diversity of isolation and expansion methods are applied. Here, we report on a robust and standardized method for hUC-MSC isolation and expansion. Using 90 hUC donors, we compared and optimized critical variables during each phase of the multi-step procedure involving UC collection, processing, MSC isolation, expansion and characterization. Furthermore, we assessed the effect of donor-to-donor variability regarding UC morphology and donor attributes on hUC-MSC characteristics. We demonstrated robustness of our method across 90 UC donors at each step of the procedure. With our method, UCs can be collected up to 6 h after birth, and UC-processing can be initiated up to 48 h after collection without impacting on hUC-MSC characteristics. The removal of blood vessels before explant cultures improved hUC-MSC purity. Expansion in Minimum essential medium α supplemented with human platelet lysate increased reproducibility of the expansion rate and MSC characteristics as compared with Dulbecco's Modified Eagle's Medium supplemented with fetal bovine serum. The isolated hUC-MSCs showed a purity of ∼98.9%, a viability of >97% and a high proliferative capacity. Trilineage differentiation capacity of hUC-MSCs was reduced as compared with bone marrow-derived MSCs. Functional assays indicated that the hUC-MSCs were able to inhibit T-cell proliferation demonstrating their immune-modulatory capacity. We present a robust and standardized method to isolate and expand hUC-MSCs, minimizing technical variability and thereby lay a foundation to advance reliability and comparability of results obtained from different donors and different studies. [Display omitted] [ABSTRACT FROM AUTHOR]