Blood platelets become activated and aggregate at the site of vessel injury. Upon activation by thrombin, platelets release storage pools of proteins and growth factors (GFs), including those ...involved in tissue repair. Our goal was to evaluate the potential beneficial effect of proteins released from platelet-rich clots on tendon healing. PDGF, TGF-β-1, IGF-I, HGF, VEGF and EGF were measured in human platelet-poor plasma (PPP) and in the releasates collected from either platelet-poor or platelet-rich clots prepared in vitro. We then studied the effects of the releasates on human tendon cells in culture. Releasates from both platelet-rich and platelet-poor clots stimulated tendon cell proliferation, in contrast to un-clotted PPP. The mitogenic activity of the supernatants was not decreased by the thrombin inhibitor, hirudin. Cultured tendon cells synthesise VEGF and HGF in the presence of PPP-clots and PRP-clot releasates, thus the synthesised amount was significantly higher with supernatants from platelet-rich clots than supernatants from a platelet-poor clot (
p
<
0.05). These results suggest that administering autologous platelet-rich clots may be beneficial to the treatment of tendon injuries by inducing cell proliferation and promoting the synthesis of angiogenic factors during the healing process.
Objectives. Autologous platelet-secreted growth factors (GFs) may have therapeutic effects in osteoarthritis (OA) capsular joints via multiple mechanisms. Our aim was to examine the effect of a ...platelet-derived preparation rich in growth factors (PRGFs) in OA synovial cell biology. Methods. Synovial cells were isolated from 10 osteoarthritic patients and cultured in serum-free media (basal conditions) and exposed to either a platelet-poor preparation or PRGF for 72 h. Cells activated with interleukin-1β (IL-1β) for 48 h were also exposed to PRGF. Changes in several events relevant to joint homeostasis including (i) hyaluronic acid (HA) secretion, (ii) the balance between metalloproteinase-1, -3 and -13 (MMP-1, MMP-3 and MMP-13) and tissue inhibitor-1 (TIMP-1) and (iii) the secretion of transforming growth factor-β1(TGF-β1), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), were all assessed. Results. PRGF significantly enhanced HA secretion compared with platelet-poor preparations, P < 0.05; at the same time release of TIMP-1, MMP-1, MMP-3 and MMP-13 were not affected. An increased HGF production was observed (P < 0.05) but VEGF and TGF-β1 levels remained unchanged. PRGF significantly enhanced the secretion of HA induced by IL-1β activation, P < 0.05, but it did not modify the IL-1β-induced rise in MMP-1, MMP-3 and VEGF. In contrast, PRGF-induced HGF production was abolished by the presence of IL-1β during PRGF treatment, P < 0.05. Conclusions. Intra-articular administration of PRGF might be beneficial in restoring HA concentration and switching angiogenesis to a more balanced status but does not halt the effects of IL-1β on synovial cells.
Monitoring chemical reactions that occur in small spaces or confined environments is challenging. Surface-enhanced Raman scattering (SERS) spectroscopy offers the unique possibility to monitor ...spectral changes with high sensitivity and time resolution. Herein, we report the application of composite mesoporous TiO2 films loaded with Ag nanoparticles (NPs) to track in situ chemical processes in real time. In particular, the AgNPs@TiO2 system was employed to monitor two chemical reactions: one occurring on the Ag NPs surface and another taking place in the surrounding solution. In the first case, we monitored the decarboxylation reaction of 4-mercaptobenzoic acid on Ag NPs, which allowed us to identify the conditions that favor it. In the second case, we studied the pH evolution in the nanocavities during a homogeneous alkalization process driven by chloride-assisted glycidol rupture (the Epoxide Route) and compared it with pH measurements by conventional techniques. We therefore demonstrated that the proposed nanodevice provides an excellent performance to monitor dynamic processes occurring either inside the material or in the solution in which it is immersed.
Objectives: Preparations rich in growth factors (PRGF) release them plus bioactive proteins at localized sites, with the aim of triggering healing and regenerative processes. The prevailing paradigm ...suggests that their influence on proliferation, angiogenesis and the extracellular matrix synthesis is minimal. However, variations in their composition and impact on different cell phenotypes have not been examined.
Materials and methods: Sixteen fibroblast cultures obtained from three different anatomical sites (skin, synovium and tendon) of 16 donors were exposed to the molecular pool released from PRGF scaffolds, with increasing amounts of platelets. We evaluated cell proliferation, secretion of angiogenic growth factors (VEGF and HGF), synthesis of type I collagen and hyaluronic acid (HA), considering platelet dose and anatomical origin of the cells. Activity of transforming growth factor‐beta (TGF‐β) in type I procollagen and HA synthesis was examined by adding exogenous TGF‐β to plasma preparations.
Results: All plasma preparations induced a significant proliferative response compared to non‐stimulated cells (P < 0.05). Maximum proliferation rate was obtained with PRGF with 2‐fold or 4‐fold platelet concentration. Exposure to PRGF stimulated VEGF synthesis exclusively in tendon cells (P < 0.05), which also exhibited a different pattern of HGF production (P < 0.05). PRGF enhanced HA synthesis (P < 0.05), but did not alter collagen I production. Platelet‐secreted TGF‐β may be involved in HA, but not in type I procollagen synthesis.
Conclusions: Optimizing composition and use of platelet‐rich products is crucial to enhancing the therapeutic potential of this technology. Our data show that the biological effects of PRGF may depend on concentration of platelets and on the anatomical source of the cells.
The combination of plasmonic nanoparticles and mesoporous materials is of much interest in applications such as sensing or catalysis. The production of such hybrid materials can be done in various ...ways, leading to different architectures. We present a comparative study of the SERS performance of different nanocomposite architectures comprising mesoporous TiO2 thin films and Au nanoparticles (NPs). The selection of TiO2 as mesoporous support material was based on its high chemical and mechanical stability. Au NPs of different sizes and shapes were placed at different locations of the composite and used as a plasmonic material compatible with the synthesis conditions of the mesoporous films, displaying a high chemical stability. Using p-nitrothiophenol as a molecular probe, we evaluated the performance toward surface-enhanced Raman scattering (SERS) sensing, on the basis of minimum acquisition time, spot-to-spot reproducibility, and limit of detection. The obtained results indicate that each platform features different sensing capabilities. While systems comprising Au NPs within the mesopores allow working with low acquisition times and present high signal uniformity, only a detection limit of micromolar was achieved. On the other hand, those systems made of branched Au NPs covered with mesoporous films require low acquisition times and can achieve detection limits as low as 10 pM, but signal uniformity is compromised. We propose that careful comparison of different SERS platforms based on Au NPs and mesoporous thin films will facilitate selecting an appropriate configuration for any desired application.
The aim of this study was to produce and characterize triple-layered cell sheet constructs with varying cell compositions combined or not with the fibrin membrane scaffold obtained by the technology ...of Plasma Rich in Growth Factors (mPRGF).
Human primary cultures of periodontal ligament stem cells (hPDLSCs) were isolated, and their stemness nature was evaluated. Three types of triple-layered composite constructs were generated, composed solely of hPDLSCs or combined with human umbilical vein endothelial cells (HUVECs), either as a sandwiched endothelial layer or as coculture sheets of both cell phenotypes. These three triple-layered constructs were also manufactured using mPRGF as cell sheets’ support. Necrosis, glucose consumption, secretion of extracellular matrix proteins and synthesis of proangiogenic factors were determined. Histological evaluations and proteomic analyses were also performed.
The inclusion of HUVECs did not clearly improve the properties of the multilayered constructs and yet hindered their optimal conformation. The presence of mPRGF prevented the shrinkage of cell sheets, stimulated the metabolic activity and increased the matrix synthesis. At the proteome level, mPRGF conferred a dramatic advantage to the hPDLSC constructs in their ability to provide a suitable environment for tissue regeneration by inducing the expression of proteins necessary for bone morphogenesis and cellular proliferation.
hPDLSCs’ triple-layer construct onto mPRGF emerges as the optimal structure for its use in regenerative therapeutics.
These results suggest the suitability of mPRGF as a promising tool to support cell sheet formation by improving their handling and biological functions.
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•CST avoids proteolytic enzymes for cell detachment, preserving efficiently ECM components.•The weak mechanical properties of cell sheets constitute an important limitation.•mPRGF prevents shrinkage, facilitates handling and provides biological cues.•The inclusion of HUVECs hindered the optimal formation of cell sheets constructs.•hPDLSCs’ tri-layer construct onto mPRGF emerges as the optimal option.
The synthesis of hybrid inorganic organic mesoporous films with pores displaying phosphonic acid functions and their use as template for Ag nanoparticles are presented here. The Photochemical radical ...thiol – ene addition (PRTEA) was used for the synthesis of organophosphonated thiopropyltrimethoxysilanes with either diethyl allylphosphonate (DEAP) and vinylphosphonic acid (VPA) functionalities, which quantitatively lead to two functionalizing agents with differential reactivities. Phosphonated Hybrid Mesoporous Silica Thin Films with different composition were obtained by incorporating variable amounts of the phosphonated silanes by co-condensation strategy. Structural characterization with electron microscopy, X-ray reflectometry (XRR) and small angle X-ray scattering (SAXS) in transmission mode demonstrated the synthesis of ordered mesoporous phases in all tested compositions. The chemical characteristics of the hybrid films were evaluated by Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) showing the quantitative incorporation of the two silanes. The phosphonic groups present in the hybrid mesoporous silica thin films surface improved the adsorption of Ag (I) ion, acting as complexation sites. Silver nanoparticles (NPs) were afterwards obtained by adsorption/reduction cycles using NaBH4 as reduction agent. The obtained nanocomposites presented well distributed Ag NPs, as demonstrated by electronic microscopy and UV–visible spectroscopy. Moreover, the NPs were highly stable against oxidation when included within the functional oxides, in comparison with the pure oxide counterpart. Both phosphonated functions produced a high Ag (I) and Ag NPs loading, but the different chemistry of the phosphonates had an impact on total loading and stability of the NPs. While the free phosphonic acid presented the largest Ag (I) ion adsorption, higher chemical stability of Ag NPs was achieved for the ester protected phosphonate.
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Purpose
Cell migration plays an essential role in development, wound healing, and tissue regeneration. Plasma rich in growth factors (PRGF-Endoret) technology offers a potential source of growth ...factors involved in tissue regeneration. Here, we evaluate the potential of PRGF-Endoret over tendon cells and synovial fibroblasts migration and study whether the combination of this autologous technology with hyaluronic acid (HA) improves the effect and potential of the biomaterials over the motility of both types of fibroblasts.
Methods
Migration of primary tendon cells and synovial fibroblasts after culturing with either PRGF or PPGF (plasma poor in growth factors) at different doses was evaluated. Furthermore, the migratory capacity induced by the combination of PPGF and PRGF with HA was tested.
Results
PPGF stimulated migration of both types of cells but this effect was significantly higher when PRGF was used. Tendon cells showed an increase of 212% in migratory ability when HA was combined with PPGF and of 335% in the case of HA + PRGF treatment compared with HA alone.
Conclusions
PRGF-Endoret stimulates migration of tendon cells and synovial fibroblasts and improves the biological properties of HA.
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