title: Chondrogenic differentiation and functional maturation of bovine mesenchymal stem cells in long-term agarose culture.
abstract: BACKGROUND
  The developmental history of the chondrocyte results in a cell whose biosynthetic activities are optimized to maintain the concentration and organization of a mechanically functional cartilaginous extracellular matrix. While useful for cartilage tissue engineering studies, the limited supply of healthy autologous chondrocytes may preclude their clinical use. Consequently, multipotential mesenchymal stem cells (MSCs) have been proposed as an alternative cell source.
  
  
  OBJECTIVE
  While MSCs undergo chondrogenesis, few studies have assessed the mechanical integrity of their forming matrix. Furthermore, efficiency of matrix formation must be determined in comparison to healthy chondrocytes from the same donor. Given the scarcity of healthy human tissue, this study determined the feasibility of isolating bovine chondrocytes and MSCs, and examined their long-term maturation in three-dimensional agarose culture.
  
  
  METHODS
  Bovine MSCs were seeded in agarose and induced to undergo chondrogenesis. Mechanical and biochemical properties of MSC-laden constructs were monitored over a 10-week period and compared to those of chondrocytes derived from the same group of animals maintained similarly.
  
  
  RESULTS
  Our results show that while chondrogenesis does occur in MSC-laden hydrogels, the amount of the forming matrix and measures of its mechanical properties are lower than that produced by chondrocytes under the same conditions. Furthermore, some important properties, particularly glycosaminoglycan content and equilibrium modulus, plateau with time in MSC-laden constructs, suggesting that diminished capacity is not the result of delayed differentiation.
  
  
  CONCLUSIONS
  These findings suggest that while MSCs do generate constructs with substantial cartilaginous properties, further optimization must be done to achieve levels similar to those produced by chondrocytes.
authors.affiliation: Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-8022, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Mauck
authors.forename: X
authors.initials: X
authors.lastname: Yuan
authors.forename: R S
authors.initials: RS
authors.lastname: Tuan
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D020219:Chondrogenesis; D003094:Collagen / Q000032:analysis; D003470:Culture Media; D004247:DNA / Q000032:analysis; D005109:Extracellular Matrix / Q000378:metabolism / Q000648:ultrastructure; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D011509:Proteoglycans / Q000032:analysis / Q000378:metabolism; D012685:Sepharose; D013997:Time Factors
chemical_list: D003470:Culture Media; D011509:Proteoglycans; D003094:Collagen; D004247:DNA; D012685:Sepharose