title: Tissue engineering of diseased bladder using a collagen scaffold in a bladder exstrophy model.
abstract: OBJECTIVE
  To compare the regenerative capacity of diseased bladder in a large animal model of bladder exstrophy with regeneration in healthy bladder using a highly porous collagen scaffold.
  
  
  METHODS
  Highly porous bovine type I collagen scaffolds with a diameter of 32 mm were prepared. In 12 fetal sheep a bladder exstrophy was surgically created at 79 days' gestation. Lambs were born at full term (140 days' gestation). After 1 week the bladder lesion was reconstructed and augmented with a collagen scaffold (group 1). In nine normal newborn lambs the bladder was augmented with a collagen scaffold 1 week after birth (group 2). Functional (video-urodynamics) and histological evaluation was performed at 1 and 6 months after surgery.
  
  
  RESULTS
  The survival rate was 58% in group 1 and 100% in group 2. Cystograms were normal in all lambs, besides low-grade reflux in both groups. Urodynamics showed comparable capacity between both groups and a trend to lower compliance in group 1. Histological evaluation at 1 month revealed a non-confluent urothelial layer, an immature submucosa, and initial ingrowth of smooth muscle cells. At 6 months both groups showed normal urothelial lining, standard extracellular matrix development, and smooth muscle cell ingrowth.
  
  
  CONCLUSIONS
  Bladder tissue regeneration with a collagen scaffold in a diseased bladder model and in healthy bladder resulted in comparable functional and histological outcome, with a good quality of regenerated tissue involving all tissue layers. Improvements may still be needed for larger augmentations or more severely diseased bladders.
authors.forename: Luc A J
authors.initials: LA
authors.lastname: Roelofs
authors.forename: Barbara B M
authors.initials: BB
authors.lastname: Kortmann
authors.forename: Egbert
authors.initials: E
authors.lastname: Oosterwijk
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Eggink
authors.forename: Dorien M
authors.initials: DM
authors.lastname: Tiemessen
authors.forename: A Jane
authors.initials: AJ
authors.lastname: Crevels
authors.forename: Rene M H
authors.initials: RM
authors.lastname: Wijnen
authors.forename: Willeke F
authors.initials: WF
authors.lastname: Daamen
authors.forename: Toin H
authors.initials: TH
authors.lastname: van Kuppevelt
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Geutjes
authors.forename: Wout F J
authors.initials: WF
authors.lastname: Feitz
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001746:Bladder Exstrophy / Q000473:pathology*; D002417:Cattle; D003094:Collagen; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000473:pathology*; D032389:Myocytes, Smooth Muscle; D012038:Regeneration; D012756:Sheep; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D001743:Urinary Bladder / Q000473:pathology*; D014563:Urodynamics
chemical_list: D003094:Collagen