title: Effects of external radiation in a co-culture model of endothelial cells and adipose-derived stem cells.
abstract: BACKGROUND
  The inflammatory response clinically observed after radiation has been described to correlate with elevated expression of cytokines and adhesion molecules by endothelial cells. Therapeutic compensation for this microvascular compromise could be an important approach in the treatment of irradiated wounds. Clinical reports describe the potential of adipose-derived stem cells to enhance wound healing, but the underlying cellular mechanisms remain largely unclear.
  
  
  METHODS
  Human dermal microvascular endothelial cells (HDMEC) and human adipose-derived stem cells (ASC) were cultured in a co-culture setting and irradiated with sequential doses of 2 to 12 Gy. Cell count was determined 48 h after radiation using a semi-automated cell counting system. Levels of interleukin-6 (IL-6), basic fibroblast growth factor (FGF), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined in the supernatants using enzyme-linked immunosorbent assay (ELISA). Irradiated HDMEC and ASC as well as non-irradiated co-cultures, HDMEC or ASC respectively were used as controls.
  
  
  RESULTS
  Cell count was significantly reduced in irradiated co-cultures of HDMEC and ASC compared to non-irradiated controls. Levels of IL-6, FGF, ICAM-1 and VCAM-1 in the supernatants of the co-cultures were significantly less affected by external radiation in comparison to HDMEC.
  
  
  CONCLUSIONS
  The increased expression of cytokines and adhesion molecules by HDMEC after external radiation is mitigated in the co-culture setting with ASC. These in vitro changes seem to support the clinical observation that ASC may have a stabilizing effect when injected into irradiated wounds.
authors.forename: Frank
authors.initials: F
authors.lastname: Haubner
authors.forename: Michaela
authors.initials: M
authors.lastname: Leyh
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ohmann
authors.forename: Fabian
authors.initials: F
authors.lastname: Pohl
authors.forename: Lukas
authors.initials: L
authors.lastname: Prantl
authors.forename: Holger G
authors.initials: HG
authors.lastname: Gassner
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000096:biosynthesis / Q000528:radiation effects; D042783:Endothelial Cells / Q000378:metabolism* / Q000528:radiation effects*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D011839:Radiation, Ionizing; D011878:Radiotherapy / Q000009:adverse effects; D013234:Stem Cells / Q000378:metabolism*; D014945:Wound Healing / Q000528:radiation effects*
chemical_list: D015815:Cell Adhesion Molecules; D016207:Cytokines