Orthotopic Transplantation of Functional Bioengineered Livers in Rats.

Functional bioengineered livers (FBLs) are promising alternatives to orthotopic liver transplantation. However, orthotopic transplantation of FBLs has not yet been reported. This study aimed to perform the orthotopic transplantation of FBLs in rats subjected to complete hepatectomy. FBLs were developed using rat whole decellularized liver scaffolds (DLSs) with human umbilical vein endothelial cells implanted via the portal vein, and human bone marrow mesenchymal stem cells (hBMSCs) and mouse hepatocyte cell line implanted via the bile duct. FBLs were evaluated in terms of endothelial barrier function, biosynthesis, and metabolism and orthotopically transplanted into rats to determine the survival benefit. The FBLs with well-organized vascular structures exhibited endothelial barrier function, with reduced blood cell leakage. The implanted hBMSCs and hepatocyte cell line were well aligned in the parenchyma of the FBLs. The high levels of urea, albumin, and glycogen in the FBLs indicated biosynthesis and metabolism. Orthotopic transplantation of FBLs achieved a survival time of 81.38 ± 4.263 min in rats (n = 8) subjected to complete hepatectomy, whereas control animals (n = 4) died within 30 min (p < 0.001). After transplantation, CD90-positive hBMSCs and the albumin-positive hepatocyte cell line were scattered throughout the parenchyma, and blood cells were limited within the vascular lumen of the FBLs. In contrast, the parenchyma and vessels were filled with blood cells in the control grafts. Thus, orthotopic transplantation of whole DLS-based FBLs can effectively prolong the survival of rats subjected to complete hepatectomy. In summary, this work was the first to perform the orthotopic transplantation of FBLs, with limited survival benefits, which still has important value for the advancement of bioengineered livers.