title: Toward angiogenesis of implanted bio-artificial liver using scaffolds with type I collagen and adipose tissue-derived stem cells.
abstract: OBJECTIVE
  Stem cell therapies for liver disease are being studied by many researchers worldwide, but scientific evidence to demonstrate the endocrinologic effects of implanted cells is insufficient, and it is unknown whether implanted cells can function as liver cells. Achieving angiogenesis, arguably the most important characteristic of the liver, is known to be quite difficult, and no practical attempts have been made to achieve this outcome. We carried out this study to observe the possibility of angiogenesis of implanted bio-artificial liver using scaffolds.
  
  
  METHODS
  This study used adipose tissue-derived stem cells that were collected from adult patients with liver diseases with conditions similar to the liver parenchyma. Specifically, microfilaments were used to create an artificial membrane and maintain the structure of an artificial organ. After scratching the stomach surface of severe combined immunocompromised (SCID) mice (n=4), artificial scaffolds with adipose tissue-derived stem cells and type I collagen were implanted. Expression levels of angiogenesis markers including vascular endothelial growth factor (VEGF), CD34, and CD105 were immunohistochemically assessed after 30 days.
  
  
  RESULTS
  Grossly, the artificial scaffolds showed adhesion to the stomach and surrounding organs; however, there was no evidence of angiogenesis within the scaffolds; and VEGF, CD34, and CD105 expressions were not detected after 30 days.
  
  
  CONCLUSIONS
  Although implantation of cells into artificial scaffolds did not facilitate angiogenesis, the artificial scaffolds made with type I collagen helped maintain implanted cells, and surrounding tissue reactions were rare. Our findings indicate that type I collagen artificial scaffolds can be considered as a possible implantable biomaterial.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jae Geun
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, Seoul, Korea.
authors.forename: Seon Young
authors.initials: SY
authors.lastname: Bak
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Hae
authors.initials: JH
authors.lastname: Nahm
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea. ; Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, Seoul, Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea. ; Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, Seoul, Korea.
authors.forename: Seon Ok
authors.initials: SO
authors.lastname: Min
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea. ; Graduate Program of Nano Science and Technology, Graduate School of Yonsei University, Seoul, Korea. ; Cell Therapy Center, Severance Hospital, Seoul, Korea.
authors.forename: Kyung Sik
authors.initials: KS
authors.lastname: Kim
keywords: Artificial; Biocompatible materials; Liver; Neovascularization; Physiologic; Tissue scaffolds