title: Renal tissue oxygenation in children with chronic kidney disease due to vesicoureteral reflux.
abstract: Vesicoureteral reflux (VUR) is a frequent cause of chronic kidney disease (CKD) in children. Using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI), we measured cortical and medullary oxygenation in children with CKD due to VUR and compared the results to those obtained on healthy controls.
  
  
  
  The study population comprised 37 children (19 with CKD due to VUR and 18 healthy age-matched controls). BOLD-MRI was performed before and after furosemide treatment. MR images were analyzed with the region-of-interest (ROI) technique to assess the mean R2* values (=1/T2*) of the cortex and medulla of each kidney and with the concentric object (CO) technique that divides renal parenchyma in 12 equal layers.
  
  
  
  R2* values were significantly lower (corresponding to higher oxygenation) in the cortex and medulla of kidneys of children with CKD due to VUR than in those of the healthy controls (cortex 16.4 ± 1.4 vs. 17.2 ± 1.6 s(-1) , respectively; medulla 28.4 ± 3.2 vs. 30.3 ± 1.9 s(-1) , respectively; P < 0.05), and furosemide-induced changes in medullary R2* were smaller in the former than in the latter (-5.7 ± 3.0 vs. -6.9 ± 3.4 s(-1), respectively; P < 0.05). Similar results were found with the CO technique. In children with a history of unilateral reflux (n = 9), the non-affected contralateral kidneys presented similar R2* values as the diseased kidneys, but their response to furosemide was significantly larger (-7.4 ± 3.2 vs. -5.7 ± 3.0, respectively; P = 0.05).
  
  
  
  Chronic kidney disease due to VUR is not associated with kidney tissue hypoxia in children. The significantly larger furosemide-induced decrease in medullary R2* levels in the healthy group and unaffected contralateral kidneys of the VUR group points towards more intense renal sodium transport in these kidneys.
authors.affiliation: Pediatric Nephrology Unit, Department of Pediatrics, University Hospital of Lausanne (CHUV), Rue Bugnon 46, 1011, Lausanne, Switzerland. hassib.chehade@chuv.ch.
authors.forename: Hassib
authors.initials: H
authors.lastname: Chehade
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Bastien
authors.initials: B
authors.lastname: Milani
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Ansaloni
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Anex
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bassi
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.|Radiology Department, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Piskunowicz
authors.affiliation: Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
authors.affiliation: Pediatric Nephrology Unit, Department of Pediatrics, University Hospital of Lausanne (CHUV), Rue Bugnon 46, 1011, Lausanne, Switzerland.
authors.forename: Francois
authors.initials: F
authors.lastname: Cachat
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Burnier
authors.affiliation: Service of Nephrology and Hypertension, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
authors.forename: Menno
authors.initials: M
authors.lastname: Pruijm
mesh_terms: D000293:Adolescent; D015687:Cell Hypoxia; D005260:Female; D005665:Furosemide / Q000627:therapeutic use; D006801:Humans; D007672:Kidney Cortex / Q000000981:diagnostic imaging / Q000378:metabolism*; D007679:Kidney Medulla / Q000000981:diagnostic imaging / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010101:Oxygen Consumption; D051436:Renal Insufficiency, Chronic / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism*; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000627:therapeutic use; D014718:Vesico-Ureteral Reflux / Q000150:complications*
chemical_list: D049994:Sodium Potassium Chloride Symporter Inhibitors; D005665:Furosemide
keywords: BOLD-MRI; Children; Chronic kidney disease; Hypoxia; Oxygenation; Vesicoureteral reflux