PC222. Engineered Vascular Grafts Using Three-Dimensional Printed Guides and the Ring Stacking Method
Pinnock C, Patel B, Rteil A, Kabbani L, and Lam M. PC222. Engineered Vascular Grafts Using Three-Dimensional Printed Guides and the Ring Stacking Method. J Vasc Surg Venous Lymphat Disord 2019; 69(6):e265-e266.
J Vasc Surg Venous Lymphat Disord
Objective: Developing a prosthetic graft with equivalent function and durability to arteries or veins has proved to be elusive. We introduce a novel vascular tissue engineering technique that we hope will serve patients with no viable autologous vessels to harvest. Methods: We describe our ring stacking method, which uses smooth muscle cells or fibroblasts to create custom vessels of different calibers. We use a combination of hydrogel, three-dimensional printed guides, and custom-molded plates to create cellular vascular rings (Fig 1), which are then stacked to create a cylindrical, viable vascular construct (Fig 2). The media layer is formed by creating rings of human vascular smooth muscle cells. An adventitial layer is created by applying human fibroblasts into our vessel-making protocol, which is completed by stimulating the vessel with ascorbic acid and transforming growth factor β for collagen production. Mechanical testing was performed to assess tensile strength, histologic evaluation to assess anatomic structure, and perfusion testing to assess hemodynamics. Immunogenicity testing was carried out by submerging the engineered vessel in whole blood for 24 hours and then immunostaining for leukocytes (CD45). Results: Our ring stacking method can be used to create different caliber vessels (Fig 2). Tensile testing of the vessels shows elastic and tensile strength that correlated with ring and vessel girth. Histologic analysis shows high cellularity with smooth muscle cell phenotype comparable to a native vessel and organized collagen in the adventitia. During perfusion testing, vessels were able to endure flow rates of 100 to 417 mL/min. No CD45 immunostaining was visualized during immunogenicity testing, suggesting that our tissue-engineered vessels have low immunogenic potential. Conclusions: The ideal bioprosthetic cardiovascular bypass graft needs to satisfy a broad range of characteristics. Initial testing of our graft shows adequate strength, viscoelasticity, and biocompatibility. Future directions for our laboratory include in vivo graft studies and more extensive flow and immunogenicity testing. [Figure presented][Figure presented]