title: Optimal timing of prenatal treatment of obstructive uropathy in the fetal lamb.
abstract: OBJECTIVE
  It was still unclear how urinary tract obstruction alters normal nephrogenesis and leads to renal dysplasia. The authors created an obstructive uropathy model in fetal lambs and reviewed the pathology of the obstructed kidney to determine the optimal timing for decompression of the obstruction.
  
  
  METHODS
  Obstructive uropathy was created in fetal lambs at 60 days' gestation by ligating the urethra and urachus. They were delivered 20 to 31 days later by cesarian section. The kidneys were processed for histologic examination.
  
  
  RESULTS
  Thirty-four 60-day lambs were operated on. Dysplastic changes were noted in 25 fetuses, and 24 fetuses had cysts in the nephrogenic zone. The cystic components in multicystic dysplastic kidneys (MCDK) are mainly in the proximal tubules.
  
  
  CONCLUSIONS
  In utero urinary tract obstruction causes reduction of numbers of functioning nephrons and produces cysts in the nephrogenic zone and in the deeper cortex. These cysts and dilated proximal tubules suppress new nephron formation. Twenty days after obstruction, there were early features of dysplasia, but the nephrogenic zones still were present. Early shunting may salvage renal function.
authors.affiliation: Division of Pediatric Surgery, St Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kitagawa
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Pringle
authors.forename: Junki
authors.initials: J
authors.lastname: Koike
authors.forename: Jane
authors.initials: J
authors.lastname: Zuccollo
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Seki
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Fujiwaki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sato
authors.forename: Hideki
authors.initials: H
authors.lastname: Nagae
authors.forename: Koonosuke
authors.initials: K
authors.lastname: Nakada
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005315:Fetal Diseases / Q000473:pathology*; D007668:Kidney / Q000002:abnormalities / Q000196:embryology / Q000473:pathology*; D008297:Male; D011247:Pregnancy; D012756:Sheep; D013997:Time Factors; D014524:Urethral Obstruction / Q000150:complications*