Platelet-Rich Plasma Released From Polyethylene Glycol Hydrogels Exerts Beneficial Effects on Human Chondrocytes

Coaxial electrospun PGS/PCL and PGS/PGS-PCL nanofibrous membrane containing platelet-rich plasma for skin tissue engineering

Wound healing will be enhanced using structures with therapeutic effects. This study fabricated a novel nanofibrous scaffold for skin tissue regeneration using a coaxial structure polyglycerol sebacate (PGS)/platelet-rich plasma (PRP) was embedded in the core and two different compositions were selected for the shell; in one group, polycaprolactone (PCL), and in the other group, PGS/PCL blend was used. The physical, mechanical behavior, drug delivery patterns, and cell response of scaffolds were evaluated. Results revealed that by adding PRP to the core and PGS to the shell, fiber diameters decreased to 260.8 ± 31.3 nm. It also decreased the water contact angle from 66° to 32°, that is ideal candidate for cell attachment. The drug release showed a burst release pattern in the first 30 min, followed by a continuous and slow release during the first day. Adding PGS to the shell decreased the elastic modulus, and its value reached about 500 kPa, which is near the skin elastic modulus and will lead to greater mechanical compatibility for cell proliferation. Particularly, the addition of PRP to the fiber structure enhanced the cell viability and cell adhesion with a suitable morphology. Based on the results, nanofibrous PGS-PRP/PGS-PCL dressing can enhance skin tissue regeneration.

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

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

Mesenchymal Stem Cells Cultured in a 3D Microgel Environment Containing Platelet-Rich Plasma Significantly Modify Their Chondrogenesis-Related miRNA Expression

The aim of this work is to study the effect of platelet factors on the differentiation of mesenchymal stem cells (MSCs) to hyaline cartilage chondrocytes in a three-dimensional environment. MSCs were cultured in a microgel environment with a chondrogenic medium. The microgel consisted of microspheres that combine gelatin and platelet-rich plasma (PRP). The gelatin/PRP microdroplets were produced by emulsion. The gelatin containing the microdroplets was enzymatically gelled, retaining PRP and, just before seeding the cells, platelets were activated by adding calcium chloride so that platelet growth factors were released into the culture media but not before. Platelet activation was analyzed before activation to rule out the possibility that the gelatin cross-linking process itself activated the platelets. The gene expression of characteristic chondrogenic markers and miRNA expression were analyzed in cells cultured in a differentiation medium and significant differences were found between gelation/PRP microgels and those containing only pure gelatin. In summary, the gelatin microspheres effectively encapsulated platelets that secreted and released factors that significantly contributed to cellular chondrogenic differentiation. At the same time, the microgel constituted a 3D medium that provided the cells with adherent surfaces and the possibility of three-dimensional cell-cell contact.

Platelet-rich plasma attenuates the severity of joint capsule fibrosis following post-traumatic joint contracture in rats

Background: Post-traumatic joint contracture (PTJC) mainly manifests as excessive inflammation leading to joint capsule fibrosis. Transforming growth factor (TGF)-β1, a key regulator of inflammation and fibrosis, can promote fibroblast activation, proliferation, migration, and differentiation into myofibroblasts. Platelet-rich plasma (PRP) is considered to have strong potential for improving tissue healing and regeneration, the ability to treat joint capsule fibrosis remains largely unknown. Methods: In this study, we aimed to determine the antifibrotic potential of PRP in vivo or in vitro and its possible molecular mechanisms. The TGF-β1-induced primary joint capsule fibroblast model and rat PTJC model were used to observe several fibrotic markers (TGF-β1, α-SMA, COL-Ⅰ, MMP-9) and signaling transduction pathway (Smad2/3) using histological staining, qRT-PCR and western blot. Results: Fibroblasts transformed to myofibroblasts after TGF-β1 stimulation with an increase of TGF-β1, α-SMA, COL-Ⅰ, MMP-9 and the activation of Smad2/3 in vitro. However, TGF-β1-induced upregulation or activation of these fibrotic markers or signaling could be effectively suppressed by the introduction of PRP. Fibrotic markers' similar changes were observed in the rat PTJC model and PRP effectively reduced inflammatory cell infiltration and collagen fiber deposition in the posterior joint capsule. Interestingly, HE staining showed that articular cartilage was degraded after rat PTJC, and PRP injection also have the potential to protect articular cartilage. Conclusion: PRP can attenuate pathological changes of joint capsule fibrosis during PTJC, which may be implemented by inhibiting TGF-β1/Smad2/3 signaling and downstream fibrotic marker expression in joint capsule fibroblasts.

Multifunctional thermo-sensitive hydrogel for modulating the microenvironment in Osteoarthritis by polarizing macrophages and scavenging RONS

Osteoarthritis (OA) is a common degenerative joint disease that can lead to disability. Blocking the complex malignant feedback loop system dominated by oxidative stress and pro-inflammatory factors is the key to treating OA. Here, we develop a multifunctional composite thermo-sensitive hydrogel (HPP@Cu gel), which is utilized by Poloxamer 407 (P407) and hyaluronic acid (HA) mixture as the gel matrix, then physically mixed with copper nanodots (Cu NDs) and platelet-rich plasma (PRP). Cu NDs is a novel nano-scavenger of reactive oxygen and nitrogen species (RONS) with efficient free radical scavenging activity. HPP@Cu gel is injected into the articular cavity, where it form an in situ gel that slowly released Cu NDs, HA, and PRP, prolonging the duration of drug action. Our results indicate that HPP@Cu gel could efficiently remove RONS from inflammatory sites and promote repolarization of macrophages to an anti-inflammatory phenotype. The HPP@Cu gel therapy dramatically reduces cartilage degradation and inflammatory factor production in OA rats. This study provides a reliable reference for the application of injectable hydrogels in inflammatory diseases associated with oxidative stress.

Preparation and Characterization of Plasma-Derived Fibrin Hydrogels Modified by Alginate di-Aldehyde

Fibrin hydrogels are one of the most popular scaffolds used in tissue engineering due to their excellent biological properties. Special attention should be paid to the use of human plasma-derived fibrin hydrogels as a 3D scaffold in the production of autologous skin grafts, skeletal muscle regeneration and bone tissue repair. However, mechanical weakness and rapid degradation, which causes plasma-derived fibrin matrices to shrink significantly, prompted us to improve their stability. In our study, plasma-derived fibrin was chemically bonded to oxidized alginate (alginate di-aldehyde, ADA) at 10%, 20%, 50% and 80% oxidation, by Schiff base formation, to produce natural hydrogels for tissue engineering applications. First, gelling time studies showed that the degree of ADA oxidation inhibits fibrin polymerization, which we associate with fiber increment and decreased fiber density; moreover, the storage modulus increased when increasing the final volume of CaCl₂ (1% w/v) from 80 µL to 200 µL per milliliter of hydrogel. The contraction was similar in matrices with and without human primary fibroblasts (hFBs). In addition, proliferation studies with encapsulated hFBs showed an increment in cell viability in hydrogels with ADA at 10% oxidation at days 1 and 3 with 80 µL of CaCl₂; by increasing this compound (CaCl₂), the proliferation does not significantly increase until day 7. In the presence of 10% alginate oxidation, the proliferation results are similar to the control, in contrast to the sample with 20% oxidation whose proliferation decreases. Finally, the viability studies showed that the hFB morphology was maintained regardless of the degree of oxidation used; however, the quantity of CaCl₂ influences the spread of the hFBs.

Application of BMP in Bone Tissue Engineering

At present, bone nonunion and delayed union are still difficult problems in orthopaedics. Since the discovery of bone morphogenetic protein (BMP), it has been widely used in various studies due to its powerful role in promoting osteogenesis and chondrogenesis. Current results show that BMPs can promote healing of bone defects and reduce the occurrence of complications. However, the mechanism of BMP in vivo still needs to be explored, and application of BMP alone to a bone defect site cannot achieve good therapeutic effects. It is particularly important to modify implants to carry BMP to achieve slow and sustained release effects by taking advantage of the nature of the implant. This review aims to explain the mechanism of BMP action in vivo, its biological function, and how BMP can be applied to orthopaedic implants to effectively stimulate bone healing in the long term. Notably, implantation of a system that allows sustained release of BMP can provide an effective method to treat bone nonunion and delayed bone healing in the clinic.

Chitosan-dipotassium orthophosphate lyophilizate: a novel in situ thermogel carrier system of allogeneic platelet lysate growth factors

The clinical success of platelet-rich plasma (PRP) is constrained by its limited mechanical strength, rapid disintegration by lytic enzymes, and the consequent short-term release of bioactive growth factors (GFs). Recently, attempts to formulate PRP and other hemoderivatives, such as platelet lysate (PL) have been underway. The current study aimed to formulate allogeneic freeze-dried human platelet lysate (HPL) onto lyophilized chitosan - dipotassium hydrogen orthophosphate (CS/DHO) thermo-sensitive scaffolds. A systemic approach was employed to optimize freeze-drying (FD) procedures targeting predefined critical quality attributes (CQAs). Thermal behavior, vibrational spectroscopy, morphological and moisture content analyses were used to detect possible protein destabilization during formulation and suboptimal cake properties. The effect of CS/DHO concentrations on thermo-responsiveness and release kinetics were investigated. Finally, six-months stability and cytotoxicity studies were carried out. An optimized lyophilizate was attainable with residual moisture of less than 5% and thermoresponsive to 33 °C in less than 3 min. HPL proteins were sustainedly released over five days in a pH-sensitive manner. The stability study indicated plausible physical and biochemical stability. Cell viability testing supported the cytocompatibility of the system. Finally, the lyophilizate variant of CS/DHO thermogel overcomes limited storage stability previously posed as a challenge in freshly prepared thermogels. The developed system overcomes the drawbacks of currently used PRP treatment and provides a novel GF-rich scaffold for wound repair.

Chitosan oligosaccharides packaged into rat adipose mesenchymal stem cells-derived extracellular vesicles facilitating cartilage injury repair and alleviating osteoarthritis

Objectives

This study aimed to investigate the roles of adipose mesenchymal stem cell (AMSC)-derived extracellular vesicles (EVs) binding with chitosan oligosaccharides (COS) in cartilage injury, as well as the related mechanisms.

Results

IL-1β treatment significantly inhibited the viability and migration of chondrocytes and enhanced cell apoptosis (P < 0.05), while chitosan oligosaccharides and extracellular vesicles-chitosan oligosaccharide conjugates (EVs-COS/EVs-COS conjugates) reversed the changes induced by IL-1β (P < 0.05), and the effects of extracellular vesicles-chitosan oligosaccharide conjugates were better than those of chitosan oligosaccharides (P < 0.05). After cartilage damage, IL-1β, OPN, and p53 were significantly upregulated, COL1A1, COL2A1, OCN, RUNX2, p-Akt/Akt, PI3K, c-Myc, and Bcl2 were markedly downregulated, and extracellular vesicles-chitosan oligosaccharide conjugates reversed the expression induced by cartilage injury. Through sequencing, 760 differentially expressed genes (DEGs) clustered into four expression patterns were associated with negative regulation of the canonical Wnt, PI3K-Akt, AMPK, and MAPK signaling pathways.

Conclusion

Extracellular vesicles-chitosan oligosaccharide conjugates may serve as a new cell-free biomaterial to facilitate cartilage injury repair and improve osteoarthritis.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01086-x.

Effect of Fibrin Concentration on the In Vitro Production of Dermo-Epidermal Equivalents

Human plasma-derived bilayered skin substitutes were successfully used by our group to produce human-based in vitro skin models for toxicity, cosmetic, and pharmaceutical testing. However, mechanical weakness, which causes the plasma-derived fibrin matrices to contract significantly, led us to attempt to improve their stability. In this work, we studied whether an increase in fibrin concentration from 1.2 to 2.4 mg/mL (which is the useful fibrinogen concentration range that can be obtained from plasma) improves the matrix and, hence, the performance of the in vitro skin cultures. The results show that this increase in fibrin concentration indeed affected the mechanical properties by doubling the elastic moduli and the maximum load. A structural analysis indicated a decreased porosity for the 2.4 mg/mL hydrogels, which can help explain this mechanical behavior. The contraction was clearly reduced for the 2.4 mg/mL matrices, which also allowed for the growth and proliferation of primary fibroblasts and keratinocytes, although at a somewhat reduced rate compared to the 1.2 mg/mL gels. Finally, both concentrations of fibrin gave rise to organotypic skin cultures with a fully differentiated epidermis, although their lifespans were longer (25–35%) in cultures with more concentrated matrices, which improves their usefulness. These systems will allow the generation of much better in vitro skin models for the testing of drugs, cosmetics and chemicals, or even to “personalized” skin for the diagnosis or determination of the most effective treatment possible.

Wnt5a/Platelet-rich plasma synergistically inhibits IL-1β-induced inflammatory activity through NF-κB signaling pathway and prevents cartilage damage and promotes meniscus regeneration

Noncanonical Wnt5a is a particularly attractive growth factor to maintain chondrogenesis. Platelet-rich plasma (PRP) is an autologous blood-derived product and a source of bioactive growth factors involved in tissue regeneration. The present study aimed to investigate the effect and inflammation reaction of Wnt5a/PRP on meniscus cells, and evaluate meniscus regeneration and osteoarthritis (OA) prevention by the application of Wnt5a/PRP gel in a rabbit model of massive meniscal defect. In vitro, the proliferation, migration, differentiation, and interleukin-1 beta (IL-1β) IL-1β-induced inflammation reaction of meniscus cells treated by Wnt5a and PRP was assessed. In vivo, the anterior half of the medial meniscus of 18 New Zealand rabbits was excised and implanted with PRP gel, Wnt5a/PRP gel or untreated. After 6 and 12 weeks, the regenerated meniscus were evaluated. Wnt5a can promote the migration of meniscus cells. PRP and Wnt5a had synergistic effect in promoting the proliferation and chondrogenic differentiation of meniscus cells. The IL-1β-induced meniscus cells study showed that PRP and Wnt5a had the anti-inflammatory actions through nuclear factor kB (NF-κB) signaling pathway. PRP and Wnt5a/PRP significantly inhibited the increase of the p-p65/p65 and p-IκB-α/IκB-α ratios. In vivo transplantation of Wnt5a/PRP gel was demonstrated to promote meniscus regeneration, while reducing OA of knee joint. Wnt5a with PRP had the anti-inflammatory activity in an IL-1β-induced inflammatory model. They can synergistically improve the chondorgenic differentiation of meniscus cells. Wnt5a/PRP gel treatment could potentially be developed into a new method for meniscus regeneration and the prevention of OA.

Freeze-Drying of Platelet-Rich Plasma: The Quest for Standardization

The complex biology of platelets and their involvement in tissue repair and inflammation have inspired the development of platelet-rich plasma (PRP) therapies for a broad array of medical needs. However, clinical advances are hampered by the fact that PRP products, doses and treatment protocols are far from being standardized. Freeze-drying PRP (FD-PRP) preserves platelet function, cytokine concentration and functionality, and has been proposed as a consistent method for product standardization and fabrication of an off-the-shelf product with improved stability and readiness for future uses. Here, we present the current state of experimental and clinical FD-PRP research in the different medical areas in which PRP has potential to meet prevailing medical needs. A systematic search, according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analyses) guidelines, showed that research is mostly focused on wound healing, i.e., developing combination products for ulcer management. Injectable hydrogels are investigated for lumbar fusion and knee conditions. In dentistry, combination products permit slow kinetics of growth factor release and functionalized membranes for guided bone regeneration.

Micro-Clotting of Platelet-Rich Plasma Upon Loading in Hydrogel Microspheres Leads to Prolonged Protein Release and Slower Microsphere Degradation

Platelet-rich plasma (PRP) is an autologous blood product that contains a variety of growth factors (GFs) that are released upon platelet activation. Despite some therapeutic potential of PRP in vitro, in vivo data are not convincing. Bolus injection of PRP is cleared rapidly from the body diminishing its therapeutic efficacy. This highlights a need for a delivery vehicle for a sustained release of PRP to improve its therapeutic effect. In this study, we used microfluidics to fabricate biodegradable PRP-loaded polyethylene glycol (PEG) microspheres. PRP was incorporated into the microspheres as a lyophilized PRP powder either as is (powder PRP) or first solubilized and pre-clotted to remove clots (liquid PRP). A high PRP loading of 10% w/v was achieved for both PRP preparations. We characterized the properties of the resulting PRP-loaded PEG microspheres including swelling, modulus, degradation, and protein release as a function of PRP loading and preparation. Overall, loading powder PRP into the PEG microspheres significantly affected the properties of microspheres, with the most pronounced effect noted in degradation. We further determined that microsphere degradation in the presence of powder PRP was affected by platelet aggregation and clotting. Platelet aggregation did not prevent but prolonged sustained PRP release from the microspheres. The delivery system developed and characterized herein could be useful for the loading and releasing of PRP to promote tissue regeneration and wound healing or to suppress tissue degeneration in osteoarthritis, and intervertebral disc degeneration.