title: Using notochordal cells of developmental origin to stimulate nucleus pulposus cells and bone marrow stromal cells for intervertebral disc regeneration.
abstract: OBJECTIVE
  Bone marrow stromal cells (BMSCs) have been proposed to complement the declining population of nucleus pulposus cells (NPCs) found in a degenerative intervertebral disc. Although able to stop degeneration, they could not produce enough matrix to restore a healthy state. Looking at development, when a large amount of matrix is produced, the disc also contains notochordal cells (NCs), potential progenitors or regulators of NPCs. The aim of the study was, therefore, to combine NCs to a BMSC/NPC mix and evaluate their effects on cell phenotype and matrix production, in long-term culture.
  
  
  METHODS
  In a 3D hydrogel, NCs were co-cultured in different ratios with BMSCs and/or NPCs. Matrix production, cell morphology, and gene expression of disc markers were assessed after 4 weeks of culture.
  
  
  RESULTS
  At day 28, BMSCs/NPCs highly expressed disc matrix markers (type II collagen and aggrecan) and produced disc matrix up to 30 % of values obtained for the positive control (BMSCs under TGFβ stimulation). The addition of NCs only slightly up-regulated marker expression (6-12× increase); an up-regulation not reflected at the matrix level. During the 4 weeks of culture, however, the NC phenotype changed drastically (morphology, disc marker expression).
  
  
  CONCLUSIONS
  In contrast to previously reported short-term studies, long-term co-cultures with NCs had no substantial effects on BMSCs and NPCs, most likely due to the loss of the NC native phenotype during culture. It, therefore, appears critical to maintain this specific phenotype for a long-term effect of the NCs.
authors.affiliation: Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, GEM-Z 4.103, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands, e.potier@tue.nl.
authors.forename: Esther
authors.initials: E
authors.lastname: Potier
authors.forename: Keita
authors.initials: K
authors.lastname: Ito
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D002417:Cattle; D018920:Coculture Techniques; D024043:Collagen Type II / Q000378:metabolism; D015870:Gene Expression; D007403:Intervertebral Disc / Q000378:metabolism*; D055959:Intervertebral Disc Degeneration / Q000378:metabolism* / Q000473:pathology; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D009672:Notochord / Q000166:cytology*; D012038:Regeneration; D013552:Swine
chemical_list: D053674:Aggrecans; D024043:Collagen Type II