The current study was a preliminary evaluation of the feasibility and biologic features of three-dimensionally bio-printed tissue-engineered (3D bio-printed) vascular grafts comprising dermal fibroblast spheroids for venous replacement in rats and swine. The scaffold-free tubular tissue was made by the 3D bio-printer with normal human dermal fibroblasts. The tubular tissues were implanted into the infrarenal inferior vena cava of 4 male F344-rnu/rnu athymic nude rats and the short-term patency and histologic features were analyzed. A larger 3D bio-printed swine dermal fibroblast-derived prototype of tubular tissue was implanted into the right jugular vein of a swine and patency was evaluated at 4 weeks. The short-term patency rate was 100%. Immunohistochemistry analysis showed von Willebrand factor positivity on day 2, with more limited positivity observed on the luminal surface on day 5. Although the cross-sectional area of the wall differed significantly between preimplantation and days 2 and 5, suggesting swelling of the tubular tissue wall (both p < 0.01), the luminal diameter of the tubular tissues was not significantly altered during this period. The 3D bio-printed scaffold-free tubular tissues using human dermal or swine fibroblast spheroids may produce better tissue-engineered vascular grafts for venous replacement in rats or swine.
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