title: [DEVELOPMENT AND CHALLENGES OF ANNULUS FIBROSUS TISSUE ENGINEERING].
abstract: OBJECTIVE
  To review the biomaterial and clinical prospects of annulus tibrosus tissue engineering.
  
  
  METHODS
  The recent literature concerning annulus fibrosus tissue engineering, including cell source, bioactive molecules, and biomaterial was extensively reviewed and summarized.
  
  
  RESULTS
  Mesenchymal stem cells (MSCs) is an ideal seed cells. When annulus fibrosus cells and MSCs in the ratio of 2:1 are cultured, it shows the closest mRNA expression levels of annulus fibrosus-related markers. Bioactive molecules can be divided into 4 types: growth factors, morphogens, catabolic enzyme inhibitors, and intracellular regulators. They play an active role in promoting the synthesis of extracellular matrix, and maintaining intervertebral disc homeostasis and a balance between anabolic- and catabolic process in the disc. Based on the source, biological materials can be divided into natural materials, synthetic materials, and composite materials. The mechanical properties of the annulus fibrosus is an important basis for material design. Up to now, none of these scaffold materials is accepted as the most suitable one. The selection of scaffold materials is still to be further studied. The development of novel composite biomaterials is a trend.
  
  
  CONCLUSIONS
  The annulus fibrosus tissue engineering for the anulus fibrosus regeneration and repair will bring very broad prospects for clinical application in future.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Li
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Kong
mesh_terms: D001672:Biocompatible Materials; D018929:Cell Culture Techniques; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D007403:Intervertebral Disc / Q000166:cytology* / Q000378:metabolism; D055959:Intervertebral Disc Degeneration / Q000628:therapy; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012038:Regeneration / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods*; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D012333:RNA, Messenger