title: Insulin-like growth factor-1 gene therapy and cell transplantation in diabetic wounds.
abstract: BACKGROUND
  Impaired wound healing is a frequent phenomenon in diabetes mellitus. However, little is known of the fundamental cause of this pathology. The present study examined the effect of human insulin-like growth factor (hIGF)-1 overexpression in combination with autologous cell transplantation to diabetic wounds in a preclinical large-animal model.
  
  
  METHODS
  Diabetes was induced in Yorkshire pigs with streptozotocin. Keratinocytes were cultured and transfected with hIGF-1 or LacZ transgene. Plasmids were lipoplexed with either Lipofectin or Lipofectamin 2000. Transgene expression was assessed by enzyme-linked immunosorbent assay or X-gal staining. For in vivo studies, full-thickness wounds were created and dressed with a sealed chamber. Transfected cells were transplanted into the wounds. Wound contraction was monitored and biopsies were obtained for measurement of re-epithelialization. Wound fluid was collected and analysed for IGF-1 concentrations.
  
  
  RESULTS
  Quantification showed up to 740 ng/ml IGF-1 in vitro and significantly higher concentrations over 14 days compared to controls for the Lipofectamin 2000 group. Lipofectin-mediated gene transfer showed peak expression on day 2 with 68.5 ng/ml. In vivo, transfected cells showed peak expression of 457 ng/ml at day 1, followed by subsequent decline to 5 ng/ml on day 12 with Lipofectamin 2000. For Lipofectin, no significant IGF-1 expression could be detected. Gene therapy caused significantly faster wound closure (83%) than both controls (native-cell therapy = 57%; control wounds = 32%).
  
  
  CONCLUSIONS
  The present study demonstrates that optimized nonviral gene transfer increased IGF-1 expression in diabetic wounds by up to 900-fold. This high IGF-1 concentration in combination with cell therapy improved diabetic wound healing significantly.
authors.affiliation: Division of Plastic Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Tobias
authors.initials: T
authors.lastname: Hirsch
authors.forename: Malte
authors.initials: M
authors.lastname: Spielmann
authors.forename: Patrik
authors.initials: P
authors.lastname: Velander
authors.forename: Baraa
authors.initials: B
authors.lastname: Zuhaili
authors.forename: Oliver
authors.initials: O
authors.lastname: Bleiziffer
authors.forename: Magdalena
authors.initials: M
authors.lastname: Fossum
authors.forename: Lars
authors.initials: L
authors.lastname: Steinstraesser
authors.forename: Feng
authors.initials: F
authors.lastname: Yao
authors.forename: Elof
authors.initials: E
authors.lastname: Eriksson