Bio-electrospraying assessment toward in situ chondrocyte-laden electrospun scaffold fabrication

Electrospinning has been widely used to fabricate fibrous scaffolds for cartilage tissue engineering, but their small pores severely restrict cell infiltration, resulting in an uneven distribution of cells across the scaffold, particularly in three-dimensional designs. If bio-electrospraying is applied, direct chondrocyte incorporation into the fibers during electrospinning may be a solution. However, before this approach can be effectively employed, it is critical to identify whether chondrocytes are adversely affected. Several electrospraying operating settings were tested to determine their effect on the survival and function of an immortalized human chondrocyte cell line. These chondrocytes survived through an electric field formed by low needle-to-collector distances and low voltage. No differences in chondrocyte viability, morphology, gene expression, or proliferation were found. Preliminary data of the combination of electrospraying and polymer electrospinning disclosed that chondrocyte integration was feasible using an alternated approach. The overall increase in chondrocyte viability over time indicated that the embedded cells retained their proliferative capacity. Besides the cell line, primary chondrocytes were also electrosprayed under the previously optimized operational conditions, revealing the higher sensitivity degree of these cells. Still, their post-electrosprayed viability remained considerably high. The data reported here further suggest that bio-electrospraying under the optimal operational conditions might be a promising alternative to the existent cell seeding techniques, promoting not only cells safe delivery to the scaffold, but also the development of cellularized cartilage tissue constructs.

Multi-layered electrospinning and electrospraying approach: Effect of polymeric supplements on chondrocyte suspension

Articular cartilage was expected to be one of the first tissues to be successfully engineered, but replicating the complex fibril architecture and the cellular distribution of the native cartilage has proven difficult. While electrospinning has been widely used to reproduce the depth-dependent fibre architecture in 3D scaffolds, the chondrocyte-controlled distribution remains an unsolved problem. To incorporate cells homogeneously through the depth of scaffolds, a combination of polymer electrospinning and cell seeding is necessary. A multi-layer approach alternating between polymer electrospinning with chondrocyte electrospraying can be a solution. Still, the success of this process is related to the survival rate of the electrosprayed chondrocytes embedded within the electrospun mesh. In this regard, the present study investigated the impact of the multi-layered process and the supplementation of the electrospray chondrocyte suspension with different concentrations of Gelatin and Alginate on the viability of electrosprayed chondrocytes embedded within a Polycaprolactone/Gelatin electrospun mesh and on the mechanical properties of the resulting meshes. The addition of Gelatin in the chondrocyte suspension did not increase significantly ( p > 0.05) the percentage of viable electrosprayed chondrocytes (25%), while 3 wt% Alginate addition led to a significant ( p < 0.05) increase in chondrocyte viability (50%) relative to the case without polymer supplement (15%). Furthermore, the addition of both polymer supplements increased the mechanical properties of the multi-layer construct. These findings imply that this multi-layered approach can be applied to cartilage TE allowing for automated chondrocyte integration during scaffolds creation.

Hyaluronic Acid In Vitro Response: Viability and Proliferation Profile of Human Chondrocytes in 3D-Based Culture

Objectives This study aimed to evaluate the efficacy of hyaluronic acid in the viability and proliferation profile of human femoral-tibial joint cartilage affected by osteoarthritis using in vitro models of chondrocytes in a 2-dimensional (2D)- and 3-dimensional (3D)-based culture model by spheroids. Design In vitro study of knee cartilage affected by osteoarthritis that required surgical treatment. Samples were cultured and exposed to hyaluronic acid (100 and 500 μM; intervention group) or vehicle solution. In monolayer or 2D culture, proliferation and cell viability were measured, and nuclear morphometry was analyzed by 4′,6′-diamino-2-fenil-indol (DAPI) staining. The 3D-based culture established from the culture of articular cartilage of patients submitted to total knee arthroplasty evaluated the diameter, viability, and fusion ability of the chondrospheres created. Results Samples from 3 patients resulted in viable cultures, with chondrocyte cells exhibiting a potential for cell proliferation and viability to establish a culture. Hyaluronic acid (100 and 500 μM) improved chondrocyte viability and proliferation up to 72 hours in contact when compared with the control group, and no nuclear irregularities in morphology cell characteristics were observed by DAPI. In the 3D evaluation, hyaluronic acid (500 μM) improved the cellular feedback mechanisms, increasing the survival and maintenance of the chondrospheres after 7 days of analysis, showing the intrinsic capacity of chondrospheres grouped in the attempt to rearrange and reestablish new articular tissue. Conclusions The 2D- and 3D-based culture models with hyaluronic acid improved chondrocyte viability and proliferation and demonstrated the ability of freshly formed chondrospheres to undergo fusion when placed together in the presence of hyaluronic acid.

Klotho protects chondrocyte viability via FOXO1/3 in osteoarthritis

Purpose: To investigate the effect of Klotho and FOXO1/3 on the CH viability in OA.Methods: The survival rate of CHs, Klotho and FOXO1/3 protein expression, and ROS production were measured in the OA cartilages of different degenerative phases. H2O2 was also used to injure CHs, and the cell viability, Klotho and FOXO1/3 expressions, as well as ROS levels were investigated to clarify the effect of exogenic Klotho on the injured CHs. Additionally, in order to verify the role of FOXO1/3 in Klotho-treated CHs, SOD2, GPX1, inflammatory factors, collagen I/II, SOX9, and Runx-2 levels were analyzed by silencing FOXO1 and FOXO3 expression via siRNA transfection.Results: Klotho and FOXO1/3 expressions significantly decreased, and ROS production increased in severely human OA cartilage (p <0.05). Besides, H2O2 affected CHs viability with the suppression of Klotho and FOXO1/3 expression but ROS production was elevated. Exogenic Klotho application partly reversed the injury caused by H2O2. Furthermore, Klotho treatment of the injured CHs contributed to SOD2 and GPX1 expressions, and suppressed IL-1β, IL-6, TNF-α and MMP-13 production, resulting in the upregulation of collagen II and SOX9 as well as downregulation of collagen I and Runx-2. However, the protective effect of Klotho was weakened by FOXO1 and FOXO3 gene silencing.Conclusion: Klotho protects CHs viability by suppressing oxidative stress and inflammation, which is associated with the mediation of FOXO1 and FOXO3. These findings provide new insights into the treatment of OA.

MiR-4303 relieves chondrocyte inflammation by targeting ASPN in osteoarthritis

Background Osteoarthritis (OA) is a severe articular cartilage disease whose pathogenesis involves the inflammation of chondrocytes. MicroRNAs (miRNAs) are considered to be effective inflammation regulators. However, the regulatory mechanism of miRNAs in osteoarthritis needs to be further elucidated. In this paper, we aim to investigate the underlying mechanisms by which miR-4303 regulates osteoarthritis. Methods RT-qPCR is performed to detect the mRNA expression levels of miR-4303, ASPN, PDIA3, PIK3CA, and TRAF3. CCK-8 assay and EdU assay are carried to assess chondrocyte viability. The protein expression levels of ASPN, PCNA, Ki-67, CyclinA1, CyclinB1, CyclinD2, p27, Bax, Bcl-2, cleaved caspase-3, and Cleaved caspase-9 were measured by western blot. FACs is performed to detect the cell cycle and apoptosis of chondrocyte. ELISA is conducted to assess the levels of TNF-β, IL-1β and IL-6 in the supernatant of chondrocytes. The potential binding sites of miR-4303 and ASPN are predicted by the miRDB database and confirmed by the dual-luciferase reporter gene assay. Results Our findings illustrated that miR-4303 was down-regulated in arthritic tissues and LPS-induced chondrocytes; miR-4303 overexpression rescued the decrease in cell viability, cell cycle arrest and apoptosis induced by LPS. Furthermore, miR-4303 overexpression inhibited the release of inflammatory factors in LPS-induced chondrocytes, miR-4303 relieved chondrocyte inflammation via targeting ASPN. Conclusion MiR-4303 serves as a prognostic biomarker and relieves chondrocyte inflammation via targeting ASPN. Our findings provide novel prognostic biomarkers in predicting the progression and prognosis of osteoarthritis.

Protective Effects of Annatto Tocotrienol and Palm Tocotrienol-Rich Fraction on Chondrocytes Exposed to Monosodium Iodoacetate

Background: This study aimed to compare the chondroprotective efficacy and mechanism of annatto tocotrienol (AnTT) and palm tocotrienol-rich fraction (PT3) using SW1353 chondrocytes treated with monosodium iodoacetate (MIA). Methods: The chondrocytes were incubated with AnTT or PT3 in advance or concurrently with MIA for 24 h. The viability of the cells was tested with an MTT assay. The 8-isoprostane F2-α, extracellular matrix proteins, metalloproteinase and sex-determining region Y box protein 9 (SOX9) levels were determined using immunoassays. Results: AnTT and PT3 reversed an MIA-induced decrease in chondrocyte viability when incubated together with MIA (p < 0.05). Prior incubation with both mixtures did not produce the same effects. AnTT and PT3 cotreatment could suppress 8-isoprostane F2-α level in chondrocytes exposed to MIA (p < 0.01). Co-exposure to tocotrienols and MIA increased the type II collagen/type I collagen ratio in chondrocytes (p < 0.01). In addition, the co-exposure of AnTT and MIA for 24 h significantly upregulated SOX9, type II collagen and aggrecan levels (p < 0.05), which was not observed with co-exposure of PT3 and MIA, AnTT or PT3 exposure alone. Conclusion: AnTT and PT3 could prevent a reduction in chondrocyte viability following MIA exposure by reducing oxidative stress. In addition, AnTT might induce self-repair and anabolic activities in chondrocytes challenged with MIA.

Characterization and miRNA Profiling of Extracellular Vesicles from Human Osteoarthritic Subchondral Bone Multipotential Stromal Cells (MSCs)

Osteoarthritis (OA) is a heterogeneous disease in which the cross-talk between the cells from different tissues within the joint is affected as the disease progresses. Extracellular vesicles (EVs) are known to have a crucial role in cell-cell communication by means of cargo transfer. Subchondral bone (SB) resident cells and its microenvironment are increasingly recognised to have a major role in OA pathogenesis. The aim of this study was to investigate the EV production from OA SB mesenchymal stromal cells (MSCs) and their possible influence on OA chondrocytes. Small EVs were isolated from OA-MSCs, characterized and cocultured with chondrocytes for viability and gene expression analysis, and compared to small EVs from MSCs of healthy donors (H-EVs). OA-EVs enhanced viability of chondrocytes and the expression of chondrogenesis-related genes, although the effect was marginally lower compared to that of the H-EVs. miRNA profiling followed by unsupervised hierarchical clustering analysis revealed distinct microRNA sets in OA-EVs as compared to their parental MSCs or H-EVs. Pathway analysis of OA-EV miRNAs showed the enrichment of miRNAs implicated in chondrogenesis, stem cells, or other pathways related to cartilage and OA. In conclusion, OA SB MSCs were capable of producing EVs that could support chondrocyte viability and chondrogenic gene expression and contained microRNAs implicated in chondrogenesis support. These EVs could therefore mediate the cross-talk between the SB and cartilage in OA potentially modulating chondrocyte viability and endogenous cartilage regeneration.

Variability in the Processing of Fresh Osteochondral Allografts

The indications for fresh osteochondral allograft continue to increase. As a result, variations in graft processing and preservation methods have emerged. An understanding of these techniques is important when evaluating the optimal protocol for processing fresh osteochondral allografts prior to surgical implantation. The aim of this study is to review the literature and understand various tissue processing protocols of four leading tissue banks in the United States. Donor procurement, serological and microbiological testing, and storage procedures were compared among companies of interest. Similarities between the major tissue banks include donor screening, aseptic processing, and testing for microorganisms. Variability exists between these companies with relation to choice of storage media, antibiotic usage, storage temperature, and graft expiration dates. Potential exists for increased chondrocyte viability and lengthened time-to-expiration of the graft through a protocol of delicate tissue handling, proper choice of storage medium, adding hormones and growth factors like insulin growth factor-1 (IGF-1) to serum-free nutrient media, and storing these grafts closer to physiologic temperatures.