title: An approach for formation of vascularized liver tissue by endothelial cell-covered hepatocyte spheroid integration.
abstract: Tissue vascularization in vitro is necessary for cell transplantation and is a major challenge in tissue engineering. To construct large and regularly vascularized tissue, we focused on the integration of endothelial cell-covered spheroids. Primary rat hepatocytes were cultured on a rotary shaker, and 100-150 mum spheroids were obtained by filtration. The hepatocyte spheroids were coated with collagen by conjugation with a type 1 collagen solution. Collagen-coated hepatocyte spheroids were cocultured with human umbilical vein endothelial cells (HUVECs), and monolayered HUVEC-covered hepatocyte spheroids were constructed. Without a collagen coat, many HUVECs invaded hepatocyte spheroids but did not cover the spheroid surface. To construct regularly vascularized tissue, we packed HUVEC-covered hepatocyte spheroids in hollow fibers used for plasma separation. Packed spheroids attached to each other forming a large cellular tissue with regular distribution of HUVECs. At day 9 after packing, HUVECs invaded the hepatocyte spheroids and a dense vascular network was constructed. Collagen coating of spheroids is useful for the formation of endothelial cell-covered spheroids and subsequent regular vascularized tissue construction.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Kyushu University , Fukuoka, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Inamori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mizumoto
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Kajiwara