title: Rejuvenation of nucleus pulposus cells using extracellular matrix deposited by synovium-derived stem cells.
abstract: METHODS
  After plating for 6 passages on either plastic flasks or extracellular matrix (ECM) deposited by synovium-derived stem cells (SDSCs), expanded nucleus pulposus (NP) cells were evaluated for redifferentiation capacity.
  
  
  OBJECTIVE
  The aim was to assess the feasibility of using ECM deposited by a tissue-specific stem cell to provide a 3-dimensional microenvironment for NP cell rejuvenation.
  
  
  BACKGROUND
  Autologous disc cell-based therapy is a promising approach for intervertebral disc regeneration. Unfortunately, the current in vitro expansion of NP cells in monolayer results in dedifferentiation of these cells.
  
  
  METHODS
  Primary NP cells were plated on either plastic flasks or ECM for 6 consecutive passages. At each passage, cell numbers were counted for proliferation rate, cell phenotype was evaluated using flow cytometry, and cell differentiation status was assessed using real-time polymerase chain reaction (PCR). The pellets from expanded NP cells at passages 1, 4, and 6 were incubated in a serum-free defined medium for 14 days. Redifferentiation capacity of the expanded NP cells was evaluated using histology, biochemistry, and real-time PCR.
  
  
  RESULTS
  NP cells expanded on ECM grew much faster with a smaller size and fibroblast-like shape compared with those on plastic flasks. ECM-treated NP cells acquired an enhanced CD90 expression and higher mRNA levels of types I, II, and X collagen and aggrecan, as well as a robust redifferentiation capacity, evidenced by dramatically increased type II collagen, aggrecan, and Sox9 and decreased type I collagen for up to 6 passages.
  
  
  CONCLUSIONS
  SDSC-derived ECM can provide a tissue-specific microenvironment for the rejuvenation of NP cells with a higher proliferation rate and redifferentiation capacity. These characteristics may play a role in improving an autologous disc cell-based minimally invasive therapeutic approach toward physiological reconstruction of a biologically functional disc in the clinical setting.
authors.affiliation: Stem Cell and Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University, Morgantown, West Virginia 26506-9196, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: He
authors.forename: Ming
authors.initials: M
authors.lastname: Pei
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000378:metabolism*; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism*; D012060:Rejuvenation / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013552:Swine; D013583:Synovial Membrane / Q000166:cytology / Q000378:metabolism*