A 3D-Bioprinted Multiple Myeloma Model

Multiple myeloma (MM) is a malignancy of plasma cells accounting for ≈12% of hematological malignancies. In this study, the fabrication of a high-content in vitro MM model using a coaxial extrusion bioprinting method is reported, allowing formation of a human bone marrow-like microenvironment featuring an outer mineral-containing sheath and the inner soft hydrogel-based core. MM cells are mono-cultured or co-cultured with HS5 stromal cells that can release interleukin-6 (IL-6), where the cells show superior behaviors and responses to bortezomib in 3D models than in the planar cultures. Tocilizumab, a recombinant humanized anti-IL-6 receptor (IL-6R), is investigated for its efficacy to enhance the chemosensitivity of bortezomib on MM cells cultured in the 3D model by inhibiting IL-6R. More excitingly, in a proof-of-concept demonstration, it is revealed that patient-derived MM cells can be maintained in 3D-bioprinted microenvironment with decent viability for up to 7 days evaluated, whereas they completely die off in planar culture as soon as 5 days. In conclusion, a 3D-bioprinted MM model is fabricated to emulate some characteristics of the human bone marrow to promote growth and proliferation of the encapsulated MM cells, providing new insights for MM modeling, drug development, and personalized therapy in the future.

Direct extrusion of individually encapsulated endothelial and smooth muscle cells mimicking blood vessel structures and vascular native cell alignment

Cardiovascular diseases (CVDs) are considered the principal cause of worldwide death, being atherosclerosis the main etiology. Up to now, the predominant treatment for CVDs has been bypass surgery from autologous source. However, due to previous harvest or the type of disease, this is not always an option. For this reason, tissue engineering blood vessels (TEBV) emerged as an alternative graft source for blood vessel replacement. In order to develop a TEBV, it should mimic the architecture of a native blood vessel encapsulating the specific vascular cells in their respective layers with native alignment, and with appropriate mechanical stability. Here, we propose the extrusion of two different cell encapsulating hydrogels, mainly alginate and collagen, and a sacrificial polymer, through a triple coaxial nozzle, which in contact with a crosslinking solution allows the formation of bilayered hollow fibers, mimicking the architecture of native blood vessels. Prior to extrusion, the innermost cell encapsulating hydrogel was loaded with human umbilical vein endothelial cells (HUVECs), whereas the outer hydrogel was loaded with human aortic smooth muscle cells (HASMCs). The size of the TEVB could be controlled by changing the injection speed, presenting homogeneity between the constructs. The obtained structures were robust, allowing its manipulation as well as the perfusion of liquids. Both cell types presented high rates of survival after the extrusion process as well as after 20 days in culture (over 90%). Additionally, a high percentage of HASMC and HUVEC were aligned perpendicular and parallel to the TEBV, respectively, in their own layers, resembling the physiological arrangement found in vivo. Our approach enables the rapid formation of TEBV-like structures presenting high cell viability and allowing proliferation and natural alignment of vascular cells.

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Cellular therapies play a critical role in the treatment of spinal cord injury (SCI). Compared with cell-seeded conduits, fully cellular grafts have more similarities with autografts, and thus might result in better regeneration effects. In this study, we fabricated Schwann cell (SC)-neural stem cell (NSC) core–shell alginate hydrogel fibers in a coaxial extrusion manner. The rat SC line RSC96 and mouse NSC line NE-4C were used in this experiment. Fully cellular components were achieved in the core portion and the relative spatial positions of these two cells partially mimic the construction of nerve fibers in vivo. SCs were demonstrated to express more genes of neurotrophic factors in alginate shell. Enhanced proliferation and differentiation tendency of NSCs was observed when they were co-cultured with SCs. This model has strong potential for application in SCI repair.