Effect of chronic, low-pressure, sterile vesicoureteral reflux on renal growth and function in a porcine model: a radiologic and pathologic study.
OBJECTIVE
To study the effects of chronic, low-pressure, sterile vesicoureteral reflux (VUR) on renal growth and function in a porcine model.


METHODS
Unilateral VUR was created in five pigs, with the contralateral kidney serving as a control. Preoperatively, and 1 year later, ultrasonography, technetium 99m-dimercaptosuccinic acid (DMSA) scintigraphy, contrast material-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance (MR) imaging were performed. Morphologic abnormalities and relative uptake of (99m)Tc-DMSA were recorded. The postcontrast enhancement ratios for parenchymal regions of interest at CT and MR imaging were determined. Ruthenium 103-labeled microspheres were used to determine regional blood flow. After the pigs were sacrificed, the kidneys were excised, weighed, and analyzed pathologically.


RESULTS
Two of five refluxing kidneys had less than 45% function at scintigraphy. One of these two kidneys was small at postmortem examination. There were no other imaging or gross pathologic abnormalities. There was no significant difference in regional blood flow between the refluxing and nonrefluxing kidneys. In all of the operated on kidneys, histologic examination showed focal chronic inflammation and fibrosis.


CONCLUSIONS
Low-pressure sterile reflux into previously normal kidneys led to mild, focal, chronic interstitial inflammation and fibrosis after 1 year. Imaging findings were normal apart from a subtle decrease in tubular function in two refluxing kidneys.
Paltiel
H J
HJ
Department of Radiology, Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115, USA. harriet.paltiel@tch.harvard.edu
Mulkern
R V
RV
Perez-Atayde
A
A
Connolly
L P
LP
Zurakowski
D
D
Treves
S T
ST
Atala
A
A
D000818:Animals; D002908:Chronic Disease; D003287:Contrast Media; D005260:Female; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D019275:Radiopharmaceuticals; D012079:Renal Circulation; D013556:Swine, Miniature; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014567:Urography; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis / Q000503:physiopathology*
D003287:Contrast Media; D019275:Radiopharmaceuticals; D019783:Technetium Tc 99m Dimercaptosuccinic Acid