title: Serum and urine cystatin C levels in children with post-pyelonephritic renal scarring: a pilot study.
abstract: OBJECTIVE
  We aimed to investigate in children with a history of acute pyelonephritis the influence of unilateral post-pyelonephritic renal scarring detected by DMSA scan on serum (S(CysC)) and urine cystatin C (U(CysC)) as well as upon other traditional markers of renal damage.
  
  
  METHODS
  Children with DMSA proven pyelonephritis (n = 28) were grouped as either scar [+] (n = 19, unilateral renal scarring) or scar [-] (no scarring, n = 9). The scar [+] group was further divided into scar-1 (differential DMSA uptake, Delta(DMSA) </= 10%; n = 8) and scar-2 (Delta(DMSA) > 10%, n = 11) subgroups. S(CysC), serum creatinine, urine NAG, microalbumin, protein, fractional sodium excretion (FE(Na)), tubular phosphate reabsorption (TPR), and U(CysC/Cr) were evaluated in all patients.
  
  
  RESULTS
  Neither S(CysC) nor U(CysC) were affected by age, height, and weight. scar [+] versus scar [-] groups and scar-1 versus scar-2 subgroups were not different with regard to all studied parameters. S(CysC) did not increase in children with post-pyelonephritic unilateral renal scarring. However, 11 children with slightly increased (>0.95 mg/l) S(CysC) levels in scar [+] group tended to have higher Delta(DMSA), albeit not significantly. Furthermore, U(CysC/Cr) correlated well with urine microalbumin, NAG, and FE(Na) in all children and the scar [+] group (P < 0.05).
  
  
  CONCLUSIONS
  S(CysC) and U(CysC) did not differ among pediatric patients with and without unilateral post-pyelonephritic renal scarring. However, Delta(DMSA) uptake between the two kidneys tended to be raised in children with S(CysC) levels higher than the reference ranges. Additionally, U(CysC/Cr) exhibits parallelism with tubular functions.
authors.affiliation: Department of Biochemistry, Dokuz Eylül University School of Medicine, Izmir, Turkey.
authors.forename: Hüray
authors.initials: H
authors.lastname: Islekel
authors.forename: Alper
authors.initials: A
authors.lastname: Soylu
authors.forename: Zekiye
authors.initials: Z
authors.lastname: Altun
authors.forename: Uluç
authors.initials: U
authors.lastname: Yis
authors.forename: Mehmet
authors.initials: M
authors.lastname: Turkmen
authors.forename: Salih
authors.initials: S
authors.lastname: Kavukcu
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002921:Cicatrix / Q000097:blood* / Q000652:urine*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood* / Q000652:urine*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D008297:Male; D010865:Pilot Projects; D011704:Pyelonephritis / Q000150:complications* / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D018709:Statistics, Nonparametric
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins