Hal Jones, Brigham Young University
One of the major challenges that currently exists in the field of tissue engineering is the recellularization of decellularized organs. Without a constant flow of nutrient-rich blood to decellularized organs, the seeding of extracellular matrices with new cells is unlikely. Complex structures, such as the heart, require specialized cells in specific locations of the organ, rendering traditional two-dimensional cell culture procedures impractical. Due to these complications, past tissue engineering efforts have been limited largely to the repair of avascular connective tissues, such as articular cartilage and intervertebral discs. In our project, we seek to imitate the vascular networks that surround the vital organs by printing porous collagen disks with internal branching capillary beds. As these disks are porous, we can suspend tissue-specific cells within the collagen construct. The capillary tubes within the construct are seeded with endothelial cells, which will allow us to flow whole blood through these disks without thrombogenic effects. We expect to see that as these disks aid in the proliferation of suspended cells, three-dimensional cell culture for tissue engineering purposes will be more feasible. Another advantage of this method is the versatility of the design. The capillary beds aren’t designed for any specific tissue or organ, but we expect to see capillary growth as the implant matures in vivo allowing a more specialized network to arise from a general one. As the printing of entire organs becomes a reality in the near future, this design could be used to print intrinsic vasculatures to aid in the seeding of such matrices. The idea of printing organs with intimately superimposed vasculatures is attractive, as capillary growth is needed for the integration of any implant. We would then expect that cellularized organs equipped with a surrounding capillary bed will be less likely to be rejected or encapsulated by the patient’s body. We anticipate that much will be learned about the culture of cells in three dimensions as we succeed in growing specialized cells in existing connective tissue scaffolds. It would be the next step in making recellularized or entirely printed organs a viable option for patients in the future.