Summary
Introduction
In the pediatric patient whose ureteropelvic junction obstruction (UPJO) is not always
symptomatic, imaging is the most common means of detecting surgical success. There
is interest, however, in other means of post-operative monitoring. A panel of antimicrobial
peptides (AMPs) has been previously found to be elevated in UPJO, but the impact of
surgical correction on these AMPs is unknown.
Objective
To determine if elevated levels of candidate urinary AMP biomarkers of urinary tract
obstruction decrease following UPJO repair.
Study design
Pediatric patients undergoing surgical correction of an UPJO were recruited for participation.
Bladder urine from uninfected consenting/assenting patients was collected immediately
prior to surgery and then at least 6 months afterward. Based on prior studies demonstrating
significant elevation of beta defensin 1 (BD-1), hepatocarcinoma-intestine-pancreas/pancreatitis-associated
protein (HIP/PAP), cathelicidin (LL-37), and neutrophil gelatinase-associated lipocalin
(NGAL) in patients with UPJO versus control patients, we performed enzyme-linked immunosorbent
assays on these four AMPs to compare their expression before and after surgical intervention.
If found to significantly decrease, AMP levels were compared to healthy controls.
AMP levels were normalized to urine creatinine. Results were analyzed with paired
t test or Wilcoxon test using Graphpad software. Correlation was calculated using
Pearson or Spearman correlation. A p-value of <0.05 was considered significant.
Results
13 UPJO patients were included in this study; 9 were male (69%). Age at surgery was
a median of 4.3 years (average 6.1, range 0.4–18.4 years). Follow-up urine samples
were collected a median of 27.4 months after surgery (average 27.4; range 7.8–45.3
months). All 13 patients had clinical improvement and/or signs of improved hydronephrosis
on post-operative imaging. HIP/PAP and BD-1 significantly decreased in post-surgical
samples compared to pre-surgical samples (p = 0.02 and 0.01, respectively); NGAL and
LL-37 did not significantly change. Overall, HIP/PAP decreased in 12 patients (92%)
and BD-1 decreased in 11 patients (85%). BD-1 levels after successful repair were
not different from healthy controls (p = 0.06).
Discussion
Urinary biomarkers of obstruction should detect significant obstructive pathology
as well as reflect its resolution. This would enable their use in post-operative monitoring
and augment current methods of determining successful surgical outcome through imaging.
Conclusions
Graphical AbstractUrinary markers before (Pre) and after (Post) successful surgical correction. HIP/PAP
and BD-1 expression significantly decrease upon paired analysis after successful surgical
correction for ureteropelvic junction obstruction (∗p = 0.0215; ∗∗p = 0.0052).
Keywords
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Article info
Publication history
Published online: March 29, 2020
Accepted:
March 10,
2020
Received:
November 5,
2019
Identification
Copyright
© 2020 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
