Normal differential renal function does not indicate a normal kidney after partial ureteropelvic obstruction and subsequent relief in 2-week-old piglets.
ABSTRACT We investigated the functional consequences of relieving ureteric obstruction in young pigs with experimental hydronephrosis (HN) induced by partial unilateral ureteropelvic obstruction.
Three groups of animals were followed from the age of 2 weeks to the age of 14 weeks: Eight animals had severe or grades 3-4 HN throughout the study. Six animals had relief of the obstruction after 4 weeks. Six animals received sham operations at both ages. Morphological and functional examinations were performed at age 6 weeks and again at age 14 weeks and consisted of magnetic resonance imaging (MRI), technetium-diethylenetriaminepentaaceticacid ((99m)Tc-DTPA) renography, renal technetium-dimercaptosuccinicacid ((99m)Tc-DMSA) scintigraphy, and glomerular filtration rate (GFR) measurement.
After relief of the partial obstruction, there was reduction of the pelvic diameter and improvement of urinary drainage. Global and relative kidney function was not significantly affected by either obstruction or its relief. Renal (99m)Tc-DMSA scintigraphy showed a change in both the appearance of the kidney and a change in the distribution within kidneys even after relief of obstruction.
This study shows that partial ureteric obstruction in young pigs may be associated with little effect on global and differential kidney function. However, even after relief of HN, the distribution of (99m)Tc-DMSA in the kidney remains abnormal suggesting that a normal differential renal function may not represent a normal kidney.
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ABSTRACT: Congenital ureteropelvic junction (UPJ) obstruction is a common developmental anomaly. To elucidate the mechanisms underlying the renal consequences of congenital UPJ obstruction, we have developed a new model of variable partial unilateral ureteral obstruction (UUO) in the neonatal rat. Rat pups were subjected to sham-operation, complete UUO, or variable partial UUO within the first day of life. After 14 or 28 days, the relative number of glomeruli, cell proliferation, tubular apoptosis, tubular atrophy, and interstitial fibrosis were quantitated in histologic sections. Glomerular filtration rate (GFR) was determined after 28 days of partial or complete UUO. Following 70% to 75% reduction in ureteral diameter, renal growth from 14 to 28 days was reduced by 60%, and the number of glomeruli decreased by 50%. Renal pelvic diameter increased in proportion to the severity of obstruction following 14 days of partial UUO, and by 28 days, was maximally dilated regardless of the luminal diameter. Renal proliferation was increased, while tubular apoptosis, tubular atrophy, and interstitial fibrosis were less severe 14 days following partial UUO than in complete UUO. GFR was reduced by 80%, and proteinuria developed following 28 days of partial UUO. Renal function is impaired by chronic ipsilateral partial UUO, which reduces the number of nephrons, and leads to progressive renal pelvic dilatation. Tubular atrophy and interstitial fibrosis develop prior to significant renal pelvic dilatation. Correlation of clinically measurable parameters with renal morphometry or imaging studies in this model may lead to new approaches to the management of congenital UPJ obstruction.Kidney International 02/2005; 67(1):42-52. · 7.92 Impact Factor
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ABSTRACT: Pelvi-ureteric function was studied in pigs with experimental urinary tract obstruction, and again, 5 weeks after relief of the obstruction. Study parameters comprised EMG records taken from pelvis and ureter, measurements of intrapelvic pressure and urine flow, and some supplementary studies of renal function. Total obstruction of 5 and 6 weeks duration induced by cuffing the proximal ureter occasioned severe hydronephrosis and renal failure. Pelvic peristaltic activity was of low frequency, and abnormality was clearly more marked after the longer period of obstruction. There was, for example, some preservation of pelvi-ureteric synergism at 5 weeks, but at 6 weeks ureteric activity was wholly autonomous. Pelvic function was similarly isolated, and non productive. Inspection 5 weeks after reconstruction by pelvis resection and neo-anastomosis of the ureter showed continued absence of renal function and no restitution of normal peristaltic patterns. Partial obstruction, effected by implantation of the ureter in the psoas muscle, induced mild pelvic dilatation and impaired renal function, but there were only minor signs of disruption of normal anterograde pelvi-ureteric activity - irregularities, pauses in activity, and double activity complexes. When the ureter was freed functional patterns returned to normal. Both during obstruction and after relief, pelvic pressure increases during forced diuresis were the equivalent of or lower than the pre-determined norm. Cautery at the pelvi-ureteric junction destroyed the musculature and induced a progressive (fibrous stenosis. There was progressive dissociation of pelvi-ureteric activity, total when obstruction was total in which case ureteric activity was only autonomous, and partial when obstruction was partial in which case varying degrees of synergism and autonomous activity were seen. Successful reconstruction (pelvic resection and neo-anastomosis of the ureter) restored an apparent synergism in pelvi-ureteric function.Acta chirurgica Scandinavica. Supplementum 02/1976; 472:17-28.
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ABSTRACT: Chronic partial ureteral obstruction of the urinary tract is a common congenital abnormality. Yet, its impact on the function of the kidney in the young has not been examined. To determine the relationship between age at the time of injury and outcome, partial ureteral obstruction was produced in guinea pigs during the first, second, third, fourth, or fifth week of life, and several variables of glomerular, proximal and distal tubular functions were measured 4 weeks later. The results were compared with those obtained in the contralateral kidney and with those observed in age-matched sham-operated animals. There was a significant impairment in the growth of the obstructed kidney. The weight of the contralateral kidney in the experimental animals was significantly greater than that of the obstructed (P less than 0.001) or control (P less than 0.005) kidney, but compensatory hypertrophy decreased progressively with age, being 30% of control when the obstruction was produced in the second week of life and only 2% when the obstruction occurred at 5 weeks of age. Obstruction resulted in a marked reduction in GFR at all ages, the impairment being inversely proportional with age. Conversely, the increase in GFR on the contralateral side, which was proportional with the increase in renal mass, diminished from 60.1 to 20.5% (r = 0.96, P less than 0.001) as a function age. Tubular reabsorption of phosphate was significantly lower in obstructed kidneys, particularly so in the animals sustaining obstruction during the first 2 weeks of life.(ABSTRACT TRUNCATED AT 250 WORDS)Kidney International 12/1983; 24(5):602-9. · 7.92 Impact Factor