title: Impact of aging on gene expression in a rat model of ischemic cutaneous wound healing.
abstract: BACKGROUND
  Tissue ischemia and aging are independent features associated with the healing impairment of cutaneous wounds. However, the pathophysiology of these processes as they relate to impaired-healing wounds is poorly understood.
  
  
  METHODS
  A single full-thickness biopsy wound was made on both ears of young (3-6 month) and aged (>24 month) Fisher rats. One ear was rendered ischemic by transection of the vasculature at the ear base, while the other ear served as an internal nonischemic control. Wounds were harvested from 3 to 7 days and were evaluated histologically for either granulation tissue formation and epithelialization. Total RNA from wounds harvested at postoperative day 7 was probed using a nylon-based cDNA array to assess global genetic expression alterations.
  
  
  RESULTS
  Healing in the rat ear model is impaired by both ischemia and advanced age as measured by granulation tissue formation and wound epithelialization. Granulation tissue formation was affected to a greater degree by ischemia than age (-58% versus -21%, respectively) while epithelialization displayed an opposite response (-17% versus -53%, respectively). Global analysis of gene expression suggests that ischemia engenders a marked increase in genes displaying altered expression in aged animals compared to young animals. Importantly, all possible alterations in gene expression are found in samples from aged ischemic wounds, indicating that gene regulation is not simply depressed by advanced age.
  
  
  CONCLUSIONS
  Wound epithelialization appears to be affected to a greater degree by advanced age than by ischemia. The results demonstrate the distinctive phenotype presented by the clinically relevant combination of age and ischemia in an in vivo model of cutaneous wound healing.
authors.affiliation: Wound Healing Research Laboratory, Division of Plastic and Reconstructive Surgery, Northwestern University, Chicago, Illinois 60611, USA.
authors.forename: Jon E
authors.initials: JE
authors.lastname: Mogford
authors.forename: Mark
authors.initials: M
authors.lastname: Sisco
authors.forename: Steve R
authors.initials: SR
authors.lastname: Bonomo
authors.forename: Alan M
authors.initials: AM
authors.lastname: Robinson
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Mustoe
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics; D004195:Disease Models, Animal; D005260:Female; D019793:Fluorescein / Q000493:pharmacokinetics; D015870:Gene Expression / Q000502:physiology; D006097:Granulation Tissue / Q000502:physiology; D007511:Ischemia / Q000503:physiopathology*; D051381:Rats; D011916:Rats, Inbred F344; D012867:Skin / Q000293:injuries / Q000503:physiopathology*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D003287:Contrast Media; D019793:Fluorescein