title: Cell growth characteristics, differentiation frequency, and immunophenotype of adult ear mesenchymal stem cells.
abstract: Ear mesenchymal stem cells (EMSCs) represent a readily accessible population of stem-like cells that are adherent, clonogenic, and have the ability to self-renew. Previously, we have demonstrated that they can be induced to differentiate into adipocyte, osteocyte, chondrocyte, and myocyte lineages. The purpose of the current study was to characterize the growth kinetics of the cells and to determine their ability to form colonies of fibroblasts, adipocytes, osteocytes, and chondrocytes. In addition, the immunophenotypes of freshly isolated and culture-expanded cells were evaluated. From 1 g of tissue, we were able to isolate an average of 7.8 x 10(6) cells exhibiting a cell cycle length of approximately 2-3 days. Colony-forming unit (CFU) assays indicated high proliferation potential, and confirmed previously observed multipotentiality of the cells. Fluorescence-activated cell sorting (FACS) showed that EMSCs were negative for hematopoietic markers (CD4, CD45), proving that they did not derive from circulating hematopoietic cells. The FACS analyses also showed high expression of stem cell antigen-1 (Sca-1) with only a minor population of cells expressing CD117, thus identifying Sca-1 as the more robust stem cell biomarker. Additionally, flow cytometry data revealed that the expression patterns of hematopoietic, stromal, and stem cell markers were maintained in the passaged EMSCs, consistent with the persistence of an undifferentiated state. This study indicates that EMSCs provide an alternative model for in vitro analyses of adult mesenchymal stem cells (MSCs). Further studies will be necessary to determine their utility for tissue engineering and regenerative medical applications.
authors.affiliation: Regenerative Biology Laboratory, Louisiana State University System, Baton Rouge, Louisiana. , Department of Animal Physiology, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Staszkiewicz
authors.forename: Trivia P
authors.initials: TP
authors.lastname: Frazier
authors.forename: Brian G
authors.initials: BG
authors.lastname: Rowan
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Bunnell
authors.forename: Ernest S
authors.initials: ES
authors.lastname: Chiu
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gimble
authors.forename: Barbara
authors.initials: B
authors.lastname: Gawronska-Kozak
mesh_terms: D053687:Adult Stem Cells / Q000378:metabolism / Q000502:physiology; D000367:Age Factors; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement; D049109:Cell Proliferation; D003114:Colony-Forming Units Assay; D004423:Ear / Q000502:physiology; D004526:Efficiency; D016130:Immunophenotyping; D059630:Mesenchymal Stem Cells / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D015415:Biomarkers