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In the field of tissue engineering, diverse types of bioscaffolds are being developed currently for osteochondral defect applications. In this work, a novel scaffold based on platelet rich plasma (PRP) and hyaluronic acid with mesenchymal stem cells (MSCs) has been evaluated to observe its effect on immobilized cells. The bioscaffolds were prepared by mixing different volumes of synovial fluid (SF) with PRP from patients obtaining three formulations at PRP-SF ratios of 3:1, 1:1 and 1:3 (v/v). The live/dead staining revealed that although the cell number of each type of bioscaffold was different, these this constructs provide cells with a suitable environment for their viability and proliferation. Moreover, immobilized MSCs showed their ability to secrete fibrinolytic enzymes, which vary depending on the fibrin amount of the scaffold. Immunohistochemical analysis revealed the positive staining for collagen type II in all cases, proving the biologic action of SF derived MSCs together with the suitable characteristics of the bioscaffold for chondrogenic differentiation. Considering all these aspects, this study demonstrates that these cells-based constructs represent an attractive method for cell immobilization, achieving completely autologous and biocompatible scaffolds. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 377-385, 2018. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of intra-articular (IA) or a combination of intra-articular and intraosseous (IO) infiltration of Platelet Rich Plasma (PRP) on the cellular content of synovial fluid (SF) of osteoarthritic patients. Thirty-one patients received a single infiltration of PRP either in the IA space (n=14) or in the IA space together with two IO infiltrations, one in the medial femoral condyle and one in the tibial plateau (n=17). SF was collected before and after one week of the infiltration. The presence in the SF of mesenchymal stem cells (MSCs), monocytes, and lymphocytes was determined and quantified by flow cytometry. The number and identity of the MSCs were further confirmed by colony-forming and differentiation assays. PRP infiltration into the subchondral bone (SB) and the IA space induced a reduction in the population of MSCs in the SF. This reduction in MSCs was further confirmed by colony-forming (CFU-F) assay. On the contrary, IA infiltration alone did not cause variations in any of the cellular populations by flow cytometry or CFU-F assay. The SF of osteoarthritic patients contains a population of MSCs that can be modulated by PRP infiltration of the SB compartment. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess a novel approach to treating severe knee osteoarthritis by targeting synovial membrane, superficial articular cartilage, synovial fluid, and subchondral bone by combining intra-articular injections and intraosseous infiltrations of platelet rich plasma. We explored a new strategy consisting of intraosseous infiltrations of platelet rich plasma into the subchondral bone in combination with the conventional intra-articular injection in order to tackle several knee joint tissues simultaneously. We assessed the clinical outcomes through osteoarthritis outcome score (KOOS) and the inflammatory response by quantifying mesenchymal stem cells in synovial fluid. There was a significant pain reduction in the KOOS from baseline (61.55±14.11) to week 24 (74.60±19.19), after treatment (p=0.008), in the secondary outcomes (symptoms, p=0.004; ADL, p=0.022; sport/rec., p=0.017; QOL, p=0.012), as well as VAS score (p<0.001) and Lequesne Index (p=0.008). The presence of mesenchymal stem cells in synovial fluid and colony-forming cells one week after treatment decreased substantially from 7.98±8.21 MSC/μL to 4.04±5.36 MSC/μL (p=0.019) and from 601.75±312.30 to 139.19±123.61  (p=0.012), respectively. Intra-articular injections combined with intraosseous infiltrations of platelet rich plasma reduce pain and mesenchymal stem cells in synovial fluid, besides significantly improving knee joint function in patients with severe knee osteoarthritis. This trial is registered on EudraCT with the number 2013-003982-32. [ABSTRACT FROM AUTHOR]

Background. The interests in mesenchymal stem cells (MSCs) and their application in cell therapy have resulted in a better understanding of the basic biology of these cells. Recently hypoxia has been indicated as crucial for complete chondrogenesis. We aimed at analyzing bone marrow MSCs (BM-MSCs) differentiation capacity under normoxic and severe hypoxic culture conditions. Methods. MSCs were characterized by flow cytometry and differentiated towards adipocytes, osteoblasts, and chondrocytes under normoxic or severe hypoxic conditions. The differentiations were confirmed comparing each treated point with a control point made of cells grown in DMEM and fetal bovine serum (FBS). Results. BM-MSCs from the donors displayed only few phenotypical differences in surface antigens expressions. Analyzing marker genes expression levels of the treated cells compared to their control point for each lineage showed a good differentiation in normoxic conditions and the absence of this differentiation capacity in severe hypoxic cultures. Conclusions. In our experimental conditions, severe hypoxia affects the in vitro differentiation potential of BM-MSCs. Adipogenic, osteogenic, and chondrogenic differentiations are absent in severe hypoxic conditions. Our work underlines that severe hypoxia slows cell differentiation by means of molecular mechanisms since a decrease in the expression of adipocyte-, osteoblast-, and chondrocyte-specific genes was observed. [ABSTRACT FROM AUTHOR]