title: Clonal analysis of the proliferation potential of human bone marrow mesenchymal stem cells as a function of potency.
abstract: Human mesenchymal stem cells (MSCs) from bone marrow are a heterogeneous ensemble of progenitors and lineage-committed cells, with a broad range of regenerative properties. Ex vivo expansion to produce sufficient quantities of MSCs is essential for most therapeutic applications. The present study resolves the relationship between proliferation potential of MSCs and their potency. Clonal analysis generated single-cell derived colonies of MSCs that were classified according to their trilineage potential to exhibit adipo- (A), chondro- (C), and osteogenesis (O) as a measure of potency. Multipotent OAC clones were highly proliferative with colony-forming efficiencies that ranged from 35% to 90%; whereas, O clones formed colonies with an efficiency of 5% or less (P < 0.01). Similar trends were evident during ex vivo expansion: for example, the median specific growth rate was 0.8  day(-1) (20 h doubling time) for cultures inoculated with OAC clones and was 5-fold less for inocula of O clones (P < 0.01). OA and OC clones had similar proliferation potentials. More than 75% of cells in subconfluent cultures inoculated with O clones stained positive for senescence-associated β-galactosidase activity vs. less than 10% for OAC clones (P < 0.001). Apoptotic cells were in the minority for all potency groups. Preliminary data generated during clonal analysis suggest that osteogenic potential of MSCs to produce mineralized matrix is a function of potency, as well. These results are discussed in the context of the preparation of efficacious MSC therapies by ex vivo expansion.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, Boggs Center, Room 300, New Orleans, Louisiana 70118, USA.
authors.forename: Katie C
authors.initials: KC
authors.lastname: Russell
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Lacey
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Gilliam
authors.forename: H Alan
authors.initials: HA
authors.lastname: Tucker
authors.forename: Donald G
authors.initials: DG
authors.lastname: Phinney
authors.forename: Kim C
authors.initials: KC
authors.lastname: O'Connor
mesh_terms: D050156:Adipogenesis; D017209:Apoptosis; D001853:Bone Marrow; D049109:Cell Proliferation; D002470:Cell Survival; D020219:Chondrogenesis; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D010012:Osteogenesis