title: Effect of scaffold dilution on migration of mesenchymal stem cells from fibrin hydrogels.
abstract: OBJECTIVE
  To evaluate the effect of fibrin concentrations on mesenchymal stem cell (MSC) migration out of autologous and commercial fibrin hydrogels.
  
  
  METHODS
  Blood and bone marrow from six 2- to 4-year-old horses.
  
  
  METHODS
  Autologous fibrinogen was precipitated from plasma and solubilized into a concentrated solution. Mesenchymal stem cells were resuspended in fibrinogen solutions containing 100%, 75%, 50%, and 25% of the fibrinogen precipitate solution. Fibrin hydrogels were created by mixing the fibrinogen solutions with MSCs and thrombin on tissue culture plates. After incubation for 24 hours in cell culture medium, the MSCs that had migrated onto the tissue culture surface and beyond the boundary of the hydrogels were counted. This procedure was repeated with a commercial fibrin sealant.
  
  
  RESULTS
  Hydrogel-to-surface MSC migration was detected for all fibrin hydrogels. Migration from the 25% autologous hydrogels was 7.3-, 5.2-, and 4.6-fold higher than migration from 100%, 75%, and 50% autologous hydrogels, respectively. The number of migrating cells from 100%, 75%, and 50% autologous hydrogels did not differ significantly. With commercial fibrin sealant, the highest magnitude of migration was from the 25% hydrogels, and it was 26-fold higher than migration from 100% hydrogels. The 75% and 50% hydrogels resulted in migration that was 9.5- and 4.2-fold higher than migration from the 100% hydrogels, respectively.
  
  
  CONCLUSIONS
  MSC migration from fibrin hydrogels increased with dilution of the fibrinogen component for both autologous and commercial sources. These data supported the feasibility of using diluted fibrin hydrogels for rapid delivery of MSCs to the surface of damaged tissues.
authors.affiliation: Orthopaedic Research Center, Department of Clinical Science, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, 80523, USA.
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Hale
authors.forename: Laurie R
authors.initials: LR
authors.lastname: Goodrich
authors.forename: David D
authors.initials: DD
authors.lastname: Frisbie
authors.forename: C Wayne
authors.initials: CW
authors.lastname: McIlwraith
authors.forename: John D
authors.initials: JD
authors.lastname: Kisiday
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D005337:Fibrin / Q000737:chemistry*; D006736:Horses; D020100:Hydrogels / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D046509:Tissue Culture Techniques; D054457:Tissue Scaffolds
chemical_list: D020100:Hydrogels; D005337:Fibrin