title: Early release of neonatal ureteral obstruction preserves renal function.
abstract: The incidence of congenital hydronephrosis is approximately 1% and is often associated with renal insufficiency. It is unknown whether early release is essential to prevent deterioration of renal function. Rats were subjected to partial unilateral ureteral obstruction (PUUO) on postnatal day 2. The obstruction was left in place or released after 1 or 4 wk. Renal blood flow (RBF) and kidney size were measured sequentially over 24 wk using MRI. In rats in which the obstruction was left in place, RBF of the obstructed kidney was progressively reduced to 0.92 +/- 0.17 vs. 1.79 +/- 0.12 ml.min(-1).100 g body wt(-1) (P < 0.05) after 24 wk. Similarly, glomerular filtration rate of the obstructed kidney was severely reduced at 24 wk: 172 +/- 36 vs. 306 +/- 42 microl.min(-1).100 g body wt(-1) (P < 0.05). These changes were preceded by development of severe hydronephrosis and obstructive nephropathy with a reduction in total protein content: 45 +/- 3 vs. 58 +/- 4 mg/kidney. Moreover, nonreleased PUUO caused a marked natriuresis (0.32 +/- 0.07 vs. 0.11 +/- 0.02 micromol.min(-1).100 g body wt(-1), P < 0.05) and impaired solute free water reabsorption (0.47 +/- 0.16 vs. 2.71 +/- 0.67 microl.min(-1).100 g body wt(-1), P < 0.05), consistent with a significant downregulation of Na-K-ATPase to 62 +/- 7%, aquaporin-1 to 53 +/- 3%, and aquaporin-3 to 53 +/- 7% of sham levels. Release after 1 wk completely prevented development of hydronephrosis, reduction in RBF and glomerular filtration rate, and downregulation of renal transport proteins, whereas release after 4 wk had no effect. These results suggest that early release of neonatal obstruction provides dramatically better protection of renal function than release of obstruction after the maturation process is completed.
authors.affiliation: The Water and Salt Research Center, Institute of Experimental Clinical Research, Aarhus Univ. Hospital-Skejby, DK-8200 Aarhus, Denmark.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Shi
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
authors.forename: Chunling
authors.initials: C
authors.lastname: Li
authors.forename: Jian Guo
authors.initials: JG
authors.lastname: Wen
authors.forename: Klaus
authors.initials: K
authors.lastname: Thomsen
authors.forename: Hans
authors.initials: H
authors.lastname: Stødkilde-Jørgensen
authors.forename: Troels Munch
authors.initials: TM
authors.lastname: Jørgensen
authors.forename: Mark A
authors.initials: MA
authors.lastname: Knepper
authors.forename: Søren
authors.initials: S
authors.lastname: Nielsen
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Djurhuus
authors.forename: Jørgen
authors.initials: J
authors.lastname: Frøkiaer
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D020346:Aquaporins / Q000378:metabolism; D001835:Body Weight / Q000502:physiology; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006869:Hydronephrosis / Q000378:metabolism; D015151:Immunoblotting; D007668:Kidney / Q000503:physiopathology*; D007677:Kidney Function Tests; D007684:Kidney Tubules / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D009318:Natriuresis / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D040901:Proteomics; D051381:Rats; D017208:Rats, Wistar; D012079:Renal Circulation / Q000502:physiology; D014517:Ureteral Obstruction / Q000503:physiopathology* / Q000628:therapy*
chemical_list: D020346:Aquaporins