Segmental up-regulation of transforming growth factor-beta in the pathogenesis of primary megaureter. An immunocytochemical study.
OBJECTIVE
To examine the maturational-delay hypothesis of primary megaureter (PM), i.e. that the condition arises by a segmental maturational delay of the ureteric wall that can resolve spontaneously within the first year of life, using comparative immunocytochemistry of ureters resected from infants and from homologous pre-natal ureters.


METHODS
Seventeen distal urinary tracts were obtained from children with PM who were referred for surgery (aged 6 months to 8 years, mean 2.1 years). These were compared with ureteric buds obtained from 11-week-old human and 11- to 38-week-old calf fetuses. The samples were immunostained using a monoclonal antibody specific for transforming growth factor beta (TGF-beta).


RESULTS
The histological appearances of the narrowed ureteric segments from patients under 18 months old were like the fetal ureteric buds at 26-38 weeks of gestation. Positive TGF-beta immunoreactions were detected in the longitudinal muscle layer in the ureter from patients 6-12 months old. Such reactions weakened progressively in those patients older than 1 year, becoming negative in all children older than 3 years. The TGF-beta immunolabelling in resected ureters was closely similar to that in fetal ureters from 20 to 26-week old calves.


CONCLUSIONS
From these results, PM should be ascribed to a segmental developmental delay of the terminal ureter arising at about 20 weeks of gestation, with a possible pathogenetic involvement of autocrine TGF-beta overexpression.
Nicotina
P A
PA
Institute of Paediatric Surgery, University of Messina, Italy.
Romeo
C
C
Arena
F
F
Romeo
G
G
D000818:Animals; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D004108:Dilatation, Pathologic / Q000151:congenital / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D015854:Up-Regulation; D014515:Ureteral Diseases / Q000151:congenital / Q000473:pathology*
D016212:Transforming Growth Factor beta