Identification of tissue sections from decellularized liver scaffolds for repopulation experiments()

BACKGROUND: Biological organ engineering is a novel experimental approach to generate functional liver grafts by decellularization and repopulation. Currently, healthy organs of small or large animals and human organs with preexisting liver diseases are used to optimize decellularization and repopulation. However, the effects of morphological changes on allo- and xenogeneic cell-scaffold interactions during repopulation procedure, e.g., using scaffold-sections, are unknown. We present a sequential morphological workflow to identify murine liver scaffold-sections with well-preserved microarchitecture. METHODS: Native livers (CONT, n = 9) and livers with experimentally induced pathologies (hepatics steatosis: STEA, n = 7; hepatic fibrosis induced by bile duct ligation: BDL, n = 9; nodular regenerative hyperplasia induced by 90% partial hepatectomy: PH, n = 8) were decellularized using SDS and Triton X-100 to generate cell-free scaffolds. Scaffold-sections were assessed using a sequential morphological workflow consisting of macroscopic, microscopic and morphological evaluation: (1) The scaffold was evaluated by a macroscopic decellularization score. (2) Regions without visible tissue remnants were localized for sampling and histological processing. Subsequent microscopical examination served to identify tissue samples without cell remnants. (3) Only cell-free tissue sections were subjected to detailed liver-specific morphological assessment using a histological and immunohistochemical decellularization score. RESULTS: Decellularization was feasible in 33 livers, which were subjected to the sequential morphological workflow. In 11 of 33 scaffolds we achieved a good macroscopic decellularization result (CONT: 3 scaffolds; STEA: 3 scaffolds; BDL: 3 scaffolds; PH: 2 scaffolds). The microscopic assessment resulted in the selection of 88 cell-free tissue sections (CONT: 15 sections; STEA: 38 sections; BDL: 30 sections; PH: 5 sections). In 27 of those sections we obtained a good histological decellularization result (CONT: 3 sections; STEA: 6 sections; BDL: 17 sections; PH: 1 section). All experimental groups contained sections with a good immunohistochemical decellularization result (CONT: 6 sections; STEA: 5 sections; BDL: 4 sections; PH: 1 section). DISCUSSION: Decellularization was possible in all experimental groups, irrespectively of the underlying morphological alteration. Furthermore, our proposed sequential morphological workflow was suitable to detect tissue sections with well-preserved hepatic microarchitecture, as needed for further repopulation experiments.