title: Short and long term fate of human AMSC subcutaneously injected in mice.
abstract: OBJECTIVE
  To study the ability of human adipose-derived mesenchymal stem cells (AMSCs) to survive over the short and long term, their biodistribution and their biosafety in vivo in tumor-prone environments.
  
  
  METHODS
  We subcutaneously injected human AMSCs from different human donors into immunodeficient SCID mice over both short- (2 and 4 mo) and long- (17 mo) term in young, and aged tumor-prone mice. Presence of human cells was studied by immunohistochemistry and polymerase chain reaction analysis in all organs of injected mice.
  
  
  RESULTS
  Subcutaneously injected AMSCs did not form teratomas at any time point. They did not migrate but remained at the site of injection regardless of animal age, and did not fuse with host cells in any organ examined. AMSCs survived in vivo for at least 17 mo after injection, and differentiated into fibroblasts of the subdermic connective tissue and into mature adipocytes of fat tissue, exclusively at the site of injection.
  
  
  CONCLUSIONS
  Our results support the assertion that AMSC may be safe candidates for therapy when injected subcutaneously because of their long term inability to form teratomas.
authors.affiliation: Pilar López-Iglesias, Alejandro Blázquez-Martínez, Maria P De Miguel, Cell Engineering Laboratory, IdiPaz, La Paz Hospital Research Institute, Madrid 28046, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: López-Iglesias
authors.forename: Alejandro
authors.initials: A
authors.lastname: Blázquez-Martínez
authors.forename: Jorge
authors.initials: J
authors.lastname: Fernández-Delgado
authors.forename: Javier
authors.initials: J
authors.lastname: Regadera
authors.forename: Manuel
authors.initials: M
authors.lastname: Nistal
authors.forename: Maria P De
authors.initials: MP
authors.lastname: Miguel