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Author Affiliations: The Institute of Clinical Medicine (Li ZZ, Xing L, Li JS, Xue R, Chandra A, Wen JG), Pediatric Urodynamic Center, Urology Department (Xing L, Li JS, Wen JG), Nephrology Department (Zhao ZZ), and Neurology Department (Chandra A), First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; The Water and Salt Research Center, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark (Nørregaard R)
Corresponding Author: Jian-Guo Wen, MD, PhD, The Pediatric Urodynamic Center, Urology Department of First Affiliated Hospital of Zhengzhou University, The Institute of Clinical Medicine Universities, Zhengzhou 450052, China (Tel: +86-371-66295219; Fax: +86-371- 66989950; Email: jgwen@zzu.edu.cn)
doi: 10.1007/s12519-012-0378-9
Background: Renal aquaporins (AQP1-4) concentration is downregulated and is in proportion to the degree of hydronephrosis graded by ultrasound in pediatric congenital hydronephrosis (CH). However, the relationship between the expression of AQP1-4 with the changes of renal function impairment (RFI) evaluated by 99mTc-DTPA renal dynamic imaging is still unclear. This study aimed to investigate the relationship between AQP1-4 expression and degree of RFI in children with CH.
Methods: The expression of AQP1-4 was evaluated in 45 children with unilateral ureteropelvic junction obstruction (28 boys and 17 girls, average age: 28¡À10 months) and 15 children undergoing nephrectomy for nephroblastoma (8 boys and 7 girls, average age: 26¡À8 months) by immunoblotting and immunohistochemistry. Renal function was graded into mild and severe RFI by 99mTc-DTPA renal dynamic imaging.
Results: One-way analysis of variance with Bonferonni's correction showed a significantly reduced protein expression of AQP1-4 in the severe RFI group compared with those in both mild RFI group and controls (AQP1: 0.52¡À0.09 vs. 0.91¡À0.06 vs. 1.23¡À0.033; AQP2: 0.68¡À0.12 vs. 1.09¡À0.06 vs. 1.52¡À0.08; AQP3: 0.59¡À0.16 vs. 0.94¡À0.08 vs. 1.31¡À0.07; AQP4: 0.64¡À0.06 vs. 1.14¡À0.07 vs. 1.61¡À0.07; P<0.001, respectively). In kidneys with severe RFI, there was a reduction in the protein concentration of all four AQP isoforms which was more pronounced compared with those seen in kidneys with mild RFI and in the controls.
Conclusion: AQP1-4 expression is reduced in proportion with the impairment degree of renal function graded by 99mTc-DTPA renal dynamic imaging in human CH.
Key words: aquaporins; congenital hydronephrosis; renal function; 99mTc-DTPA renal dynamic imaging
World J Pediatr 2012;8(4):335-341
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