title: Relevance of meniscal cell regional phenotype to tissue engineering.
abstract: OBJECTIVE
  Meniscus contains heterogeneous populations of cells that have not been fully characterized. Cell phenotype is often lost during culture; however, culture expansion is typically required for tissue engineering. We examined and compared cell-surface molecule expression levels on human meniscus cells from the vascular and avascular regions and articular chondrocytes while documenting changes during culture-induced dedifferentiation.
  
  
  METHODS
  Expressions of 16 different surface molecules were examined by flow cytometry after monolayer culture for 24 h, 1 week, and 2 weeks. Menisci were also immunostained to document the spatial distributions of selected surface molecules.
  
  
  RESULTS
  Meniscus cells and chondrocytes exhibited several similarities in surface molecule profiles with dynamic changes during culture. A greater percentage of meniscal cells were positive for CD14, CD26, CD49c, and CD49f compared to articular chondrocytes. Initially, more meniscal cells from the vascular region were positive for CD90 compared to cells from the avascular region or chondrocytes. Cells from the vascular region also expressed higher levels of CD166 and CD271 compared to cells from the avascular region. CD90, CD166, and CD271-positive cells were predominately perivascular in location. However, CD166-positive cells were also located in the superficial layer and in the adjacent synovial and adipose tissue.
  
  
  CONCLUSIONS
  These surface marker profiles provide a target phenotype for differentiation of progenitors in tissue engineering. The spatial location of progenitor cells in meniscus is consistent with higher regenerative capacity of the vascular region, while the surface progenitor subpopulations have potential to be utilized in tears created in the avascular region.
authors.affiliation: a Shiley Center for Orthopaedic Research and Education at Scripps Clinic , La Jolla , CA , USA.
authors.forename: Shawn P
authors.initials: SP
authors.lastname: Grogan
authors.affiliation: b Department of Molecular and Experimental Medicine , The Scripps Research Institute , La Jolla , CA , USA.
authors.forename: Chantal
authors.initials: C
authors.lastname: Pauli
authors.affiliation: b Department of Molecular and Experimental Medicine , The Scripps Research Institute , La Jolla , CA , USA.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Lotz
authors.affiliation: a Shiley Center for Orthopaedic Research and Education at Scripps Clinic , La Jolla , CA , USA.
authors.forename: Darryl D
authors.initials: DD
authors.lastname: D'Lima
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D005260:Female; D005453:Fluorescence; D006801:Humans; D008297:Male; D000072600:Meniscus / Q000098:blood supply / Q000166:cytology*; D008875:Middle Aged; D010641:Phenotype; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D059467:Transcriptome; D055815:Young Adult
chemical_list: D015703:Antigens, CD
keywords: Articular cartilage; cell phenotype; dedifferentiation; flow cytometry; meniscus