Genetic disorders – Development

Kidney International (2004) 65, 1155–1161; doi:10.1111/j.1523-1755.2004.00488.x

A functional immature model of chronic partial ureteral obstruction1

ASHRAF BEHARRIE, JULIE FRANC-GUIMOND2, MARIA M RODRIGUEZ, JASON AU, GASTÓN ZILLERUELO and CAROLYN L ABITBOL

Division of Pediatric Nephrology and Division of Pathology, University of Miami School of Medicine, Jackson Children's Hospital Miami, Florida

Correspondence: Carolyn Abitbol, M.D., University of Miami/Holtz Children's Hospital (M714), 1611 NW 12 Ave., UCC 247D, Miami, FL 33136 or P.O. Box 016960, Miami, FL 33101. E-mail: cabitbol@med.miami.edu

2Julie Franc-Guimond is currently a Fellow in Pediatric Urology at Alfred I. Dupont Hospital for Children, Wilmington, Delaware.

1See Editorial by Chevalier, p. 1517.

Received 17 June 2003; Revised 22 August 2003; Accepted 29 October 2003.

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Abstract

A functional immature model of chronic partial ureteral obstruction.

Background

 

The most common nonlethal congenital anomaly of the urinary tract is ureteral obstruction without dysplasia. Although rarely progressive, the morbidity associated with metabolic and surgical management is considerable. Our study was designed to measure local and systemic pathophysiologic mechanisms in an immature model of chronic partial unilateral ureteral obstruction (UUO) after completion of glomerulogenesis.

Methods

 

A partial UUO was created by the method of "psoas wrap" in young male weanling rats. Control animals were sham operated. Three groups were divided as follows: sham (N = 15), UUO (N = 18), and UUO + angiotensin-converting enzyme (ACE) (N = 16) inhibitor, enalapril. Renal glomerular and tubular functions were determined by creatinine and uric acid clearances. Diuresis was assessed by urine volume, osmolality, and fractional solute excretions from samples above and below the obstruction. Proteinuria was determined by the urine protein/creatinine ratio (Up/c).

Results

 

Proteinuria was attenuated in UUO + ACE-treated animals. The hyperuricemia of the immature UUO animals was avoided by an increase in the clearance of uric acid in the UUO + ACE-treated group. Fractional solute excretions suggested a diversion of diuresis to the contralateral unobstructed kidney.

Conclusion

 

Angiotensin blockade during chronic UUO in young rats affords protection by attenuating proteinuria, promoting uricosuria, and diverting solute diuresis. These data suggest a complex interaction of local and systemic mechanisms unique to the maturing kidney.

Keywords:

unilateral ureteral obstruction, angiotensin blockade, UPJ

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