title: The role of paracrine and autocrine signaling in the early phase of adipogenic differentiation of adipose-derived stem cells.
abstract: BACKGROUND
  High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways.
  
  
  RESULTS
  Adipogenic differentiation of human adipose-derived stem cells (ASCs) cultured in a microfluidic system was investigated under perfusion conditions with an adipogenic medium or an adipogenic medium supplemented with supernatant from differentiating ASCs (conditioned medium). Conditioned medium increased adipogenic differentiation compared to adipogenic medium with respect to accumulation of lipid-filled vacuoles and gene expression of key adipogenic markers (C/EBPα, C/EBPβ, C/EBPδ, PPARγ, LPL and adiponectin). The positive effects of conditioned medium were observed early in the differentiation process.
  
  
  CONCLUSIONS
  Using different cell densities and microfluidic perfusion cell cultures to suppress the effects of cell-released factors, we have demonstrated the significant role played by auto- or paracrine signaling in adipocyte differentiation. The cell-released factor(s) were shown to act in the recruitment phase of the differentiation process.
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, Kgs. Lyngby, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Hemmingsen
authors.forename: Søren
authors.initials: S
authors.lastname: Vedel
authors.forename: Peder
authors.initials: P
authors.lastname: Skafte-Pedersen
authors.forename: David
authors.initials: D
authors.lastname: Sabourin
authors.forename: Philippe
authors.initials: P
authors.lastname: Collas
authors.forename: Henrik
authors.initials: H
authors.lastname: Bruus
authors.forename: Martin
authors.initials: M
authors.lastname: Dufva
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000273:Adipose Tissue / Q000166:cytology*; D019898:Autocrine Communication / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D003198:Computer Simulation; D017077:Culture Media, Conditioned / Q000494:pharmacology; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects; D008954:Models, Biological; D019899:Paracrine Communication / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D017077:Culture Media, Conditioned