Partial unilateral ureteropelvic junction obstruction induced in 2-week-old piglets

Purpose: We examined effects on kidney function and morphology of a partial ureteropelvic junction obstruction induced late in the postnatal nephrogen esis period of the pig. We compared the results to a similar study on pigs with obstruction induced early in the nephrogenesis period. Materials and Methods: A total of 20 14-day-old pigs were included in the s tudy. Fifteen animals were randomized to partial unilateral obstruction and 5 were sham operated. Kidney function and morphology were analyzed regardi ng glomerular filtration rate, renographic functional share and total kidne y volume at the age of 4, 12 and 24 weeks. Results: At age 4 weeks hydronephrosis was found in all obstructed kidneys included in the study. Four obstructed kidneys had renographic functional s hare 40% or greater and 1 deteriorated to less than 40% at 24 weeks. A tota l of 11 obstructed kidneys had a functional share less than 40%, 5 increase d to a share greater than 40% at age 24 weeks and 3 had decreasing share fr om age 4 to 24 weeks. Single kidney glomerular filtration rate of the contr alateral kidneys was significantly increased at all ages. Volume of the con tralateral kidney was significantly increased at age 4 and 12 weeks. Conclusions: The variability and course of renographic functional share in kidneys subjected to partial obstruction at age 2 weeks was similar to find ings obtained in pigs obstructed at age 2 days. In contrast to these our st udy showed compensatory increase in function and size of the contralateral kidney, suggesting that contralateral compensation is an ability gained lat e in the nephrogenesis period.