title: Human hepatocytes loaded in 3D bioprinting generate mini-liver.
abstract: BACKGROUND
  Because of an increasing discrepancy between the number of potential liver graft recipients and the number of organs available, scientists are trying to create artificial liver to mimic normal liver function and therefore, to support the patient's liver when in dysfunction. 3D printing technique meets this purpose. The present study was to test the feasibility of 3D hydrogel scaffolds for liver engineering.
  
  
  METHODS
  We fabricated 3D hydrogel scaffolds with a bioprinter. The biocompatibility of 3D hydrogel scaffolds was tested. Sixty nude mice were randomly divided into four groups, with 15 mice in each group: control, hydrogel, hydrogel with L02 (cell line HL-7702), and hydrogel with hepatocyte growth factor (HGF). Cells were cultured and deposited in scaffolds which were subsequently engrafted into livers after partial hepatectomy and radiation-induced liver damage (RILD). The engrafted tissues were examined after two weeks. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, total bilirubin, CYP1A2, CYP2C9, glutathione S-transferase (a-GST), and UDP-glucuronosyl transferase (UGT-2) were compared among the groups. Hematoxylin-eosin (HE) staining and immunohistochemistry of cKit and cytokeratin 18 (CK18) of engrafted tissues were evaluated. The survival time of the mice was also compared among the four groups.
  
  
  RESULTS
  3D hydrogel scaffolds did not impact the viability of cells. The levels of ALT, AST, albumin, total bilirubin, CYP1A2, CYP2C9, a-GST and UGT-2 were significantly improved in mice engrafted with 3D scaffold loaded with L02 compared with those in control and scaffold only (P<0.05). HE staining showed clear liver tissue and immunohistochemistry of cKit and CK18 were positive in the engrafted tissue. Mice treated with 3D scaffold+L02 cells had longer survival time compared with those in control and scaffold only (P<0.05).
  
  
  CONCLUSIONS
  3D scaffold has the potential of recreating liver tissue and partial liver functions and can be used in the reconstruction of liver tissues.
authors.affiliation: Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China. shusenzheng@zju.edu.cn.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhong
authors.forename: Hai-Yang
authors.initials: HY
authors.lastname: Xie
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Shu-Sen
authors.initials: SS
authors.lastname: Zheng
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D018929:Cell Culture Techniques; D002460:Cell Line; D049109:Cell Proliferation; D048430:Cell Shape; D002470:Cell Survival; D005240:Feasibility Studies; D006085:Graft Survival; D022781:Hepatocytes / Q000378:metabolism / Q000637:transplantation*; D006801:Humans; D020100:Hydrogels; D008115:Liver Regeneration; D016031:Liver Transplantation / Q000379:methods*; D008819:Mice, Nude; D010641:Phenotype; D066330:Printing, Three-Dimensional; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D015415:Biomarkers; D020100:Hydrogels