Tendon degeneration process and injuries occur often in the elder and young part of the population, affecting negatively the activity and quality of life of people
. Tissue engineering has recently gained the attention of researches, aiming to design and produce engineered scaffolds which can emulate the native tissue properties while promoting repair and regeneration. Fiber-based approaches have been considered for anisotropic tissue application, as for example tendons, due to the possibility of fabricating very fine fibers which can reproduce the natural collagen fiber dimension and orientation . In this study, we have designed and manufactured three-dimensional (3D) multi-layered scaffolds composed of electrospun nanofibrous mat coated with thin layers of human mesenchymal stem cells (hMSC)-laden hydrogel. The electrospun fibrous component provided the mechanical characteristics, while the hydrogel properly mimicked the microenvironment and the native extracellular matrix features, guaranteeing good cell spreading, proliferation and 3D distribution. A bioreactor model was also designed and developed to biomechanically stimulate the cells encapsulated within the multi-layered scaffolds. A proper concentration of bone morphogenetic protein 12 (BMP-12) was optimized and added to the constructs in order to improve hMSC proliferation and tenogenic differentiation. The results proved that the addition of BMP-12 induced tenogenic differentiation more effectively during dynamic stimulation compared to static conditions. Moreover, dynamic culture promoted cellular integrin-mediated focal adhesions and cytoskeleton deformation response which resulted in a preferential, longitudinal cell orientation and collagen I deposition. The synergistic effect of mechanical and biochemical stimulation improved MSC proliferation, alignment and differentiation as well as collagen I deposition, revealing that the 3D multi-layered cell-laden system can be used for engineering functional tendons.
1. Andarawis-Puri N, Flatow EL, Soslowsky LJ. Tendon basic science: Development, repair, regeneration, and healing. Journal of Orthopaedic, 33, 780, 2015.
2. Ratcliffe A, Butler DL, Dyment NA, Cagle PJ Jr, Proctor CS, Ratcliffe SS, Flatow EL. Scaffolds for tendon and ligament repair and regeneration. Annals of Biomedical Engineering, 43, 819, 2015.