Asymmetrical seeding of MSCs into fibrin-poly(ester-urethane) scaffolds and its effect on mechanically induced chondrogenesis

Abstract

Mesenchymal stem cells (MSCs) are currently being investigated as candidate cells for regenerative medicine approaches for the repair of damaged articular cartilage. For these cells to be used clinically, it is important to understand how they will react to the complex loading environment of a joint in vivo. In addition to investigating alternative cell sources, it is also important for the structure of tissue‐engineered constructs and the organization of cells within them to be developed and, if possible, improved. A custom built bioreactor was used to expose human MSCs to a combination of shear and compression loading. The MSCs were either evenly distributed throughout fibrin‐poly(ester‐urethane) scaffolds or asymmetrically seeded with a small proportion seeded on the surface of the scaffold. The effect of cell distribution on the production and deposition of cartilage‐like matrix in response to mechanical load mimicking in vivo joint loading was then investigated. The results show that asymmetrically seeding the scaffold led to markedly improved tissue development based on histologically detectable matrix deposition. Consideration of cell location, therefore, is an important aspect in the development of regenerative medicine approaches for cartilage repair. This is particularly relevant when considering the natural biomechanical environment of the joint in vivo and patient rehabilitation protocols. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

Two-component thermosensitive hydrogels: Phase separation affecting rheological behavior

“…To assess the localization of HAMA, safranin-O/fast green assay was chosen as a glycosaminoglycan (GAG)-selective staining procedure, which is widely used in tissue engineering for the visualization of GAG-based components in cartilaginous matrices [44][45][46][47][48]. To this end, MH polymer mixtures enriched with 0.05% of Irgacure, were injected into a teflon mold, incubated at 37 °C for 1 hour and UV irradiated for 5 minutes using a Bluepoint 4 UV lamp (point light source, wavelength range: 300-600 nm, intensity at 5 cm: 80 mW/cm 2 , Hönle UV Technology AG, Gräfelfing, Germany) to generate cylindrical UV cross-linked hydrogels.…”

Human umbilical cord‐derived scaffolds for cartilage tissue engineering

“…Additionally, tissue scaffolds seemed to contain more GAGs than gelatin scaffolds. 34 In summary, despite promising results and advances in using tissue-derived scaffolds for cartilage tissue engineering, determining an adequate substitute tissue has not yet been achieved. The combination of static culture condition and high density cell seeding may explain the distribution of the cell population close to the upper surface of the scaffolds.…”

Multi‐Disciplinary Approaches for Cell‐Based Cartilage Regeneration

“…The mechanical activation of TGF‐β in synovial fluid by shear has also been shown . This effect can be enhanced when the cells are asymmetrically seeded, demonstrating that under loading conditions cell location has an influence on outcome . When the material is stiff enough, the application of shear superimposed over compression can lead to mechanical activation of TGF‐β in a cell‐free scaffold by removing the non‐covalently bound LAP .…”

“…86 This effect can be enhanced when the cells are asymmetrically seeded, demonstrating that under loading conditions cell location has an influence on outcome. 87 When the material is stiff enough, the application of shear superimposed over compression can lead to mechanical activation of TGF-β in a cell-free scaffold by removing the non-covalently bound LAP. 85 This offers a material testing strategy, whereby a novel material can be tested under cell-free conditions using compression and shear with latent TGF-β included in the culture medium.…”