title: Functional consequences of glucose and oxygen deprivation on engineered mesenchymal stem cell-based cartilage constructs.
abstract: OBJECTIVE
  Tissue engineering approaches for cartilage repair have focused on the use of mesenchymal stem cells (MSCs). For clinical success, MSCs must survive and produce extracellular matrix in the physiological context of the synovial joint, where low nutrient conditions engendered by avascularity, nutrient utilization, and waste production prevail. This study sought to delineate the role of microenvironmental stressors on MSC viability and functional capacity in three dimensional (3D) culture.
  
  
  METHODS
  We evaluated the impact of glucose and oxygen deprivation on the functional maturation of 3D MSC-laden agarose constructs. Since MSC isolation procedures result in a heterogeneous cell population, we also utilized micro-pellet culture to investigate whether clonal subpopulations respond to these microenvironmental stressors in a distinct fashion.
  
  
  RESULTS
  MSC health and the functional maturation of 3D constructs were compromised by both glucose and oxygen deprivation. Importantly, glucose deprivation severely limited viability, and so compromised the functional maturation of 3D constructs to the greatest extent. The observation that not all cells died suggested there exists heterogeneity in the response of MSC populations to metabolic stressors. Population heterogeneity was confirmed through a series of studies utilizing clonally derived subpopulations, with a spectrum of matrix production and cell survival observed under conditions of metabolic stress.
  
  
  CONCLUSIONS
  Our findings show that glucose deprivation has a significant impact on functional maturation, and that some MSC subpopulations are more resilient to metabolic challenge than others. These findings suggest that pre-selection of subpopulations that are resilient to metabolic challenge may improve in vivo outcomes.
authors.affiliation: Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA; Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Department of Veterans Affairs, Philadelphia, PA 19104, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Farrell
authors.affiliation: Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: J I
authors.initials: JI
authors.lastname: Shin
authors.affiliation: Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Department of Veterans Affairs, Philadelphia, PA 19104, USA; Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Smith
authors.affiliation: Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA; Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Department of Veterans Affairs, Philadelphia, PA 19104, USA. Electronic address: lemauck@mail.med.upenn.edu.
authors.forename: R L
authors.initials: RL
authors.lastname: Mauck
mesh_terms: D000818:Animals; D002356:Cartilage; D002417:Cattle; D015687:Cell Hypoxia; D002470:Cell Survival; D002478:Cells, Cultured; D005947:Glucose / Q000172:deficiency*; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D046509:Tissue Culture Techniques / Q000379:methods*; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D005947:Glucose
keywords: Chondrogenesis; Glucose; Hypoxia; Mechanical properties; Mesenchymal stem cells; Three-dimensional culture