title: Cystatin C in children on chronic hemodialysis.
abstract: BACKGROUND
  Cystatin C (CyC) concentration has been suggested as a marker of middle-molecule accumulation, hemodialysis (HD) adequacy and for estimating residual renal function (RRF), but it has not been studied in pediatric HD. High CyC is associated with increased cardiovascular disease (CVD). We investigated CyC kinetics and the effect of RRF on CyC in a pediatric HD population.
  
  
  METHODS
  A total of 21 HD sessions and 20 interdialytic periods were analyzed in seven patients, age 5-19 years, of whom four were anuric (A) and three were non-anuric (NA). CyC was measured before (preHD) and after (postHD) three standard HD sessions in 1 week and prior to the first session of the following week.
  
  
  RESULTS
  We found no difference (p=0.67) in CyC concentration between preHD CyC (9.85 ± 2.15 mg/l; A vs. NA, p=0.37) and postHD CyC (10.04 ± 2.83 mg/l; A vs NA, p=0.28). The weekly average preHD CyC median concentration was 10.14 mg/l (A vs. NA, p=0.87) and correlated with age (r=0.808, p=0.03) and height measurement (r=0.799, p=0.03), but not with RRF, single-pool Kt/V, ultrafiltration, HD duration or blood liters processed.
  
  
  CONCLUSIONS
  Cystatin C is very elevated in children on HD. It does not rise between HD sessions, is not removed by standard HD and remains at steady state; therefore, elimination is extrarenal. Low RRF does not affect CyC elimination. CyC increases with age and height. If a high CyC concentration can be proven to have a causative role in the development of CVD, routine intensified HD regimens in children may be indicated for its removal.
authors.affiliation: Pediatric Nephrology, Oklahoma University Health Sciences Center, 1200 N. Phillips Ave., Suite 14200, Oklahoma City, OK 73104, USA. oljamc@mac.com
authors.forename: Olivera
authors.initials: O
authors.lastname: Marsenic
authors.forename: Andrea
authors.initials: A
authors.lastname: Wierenga
authors.forename: Donna R
authors.initials: DR
authors.lastname: Wilson
authors.forename: Michael
authors.initials: M
authors.lastname: Anderson
authors.forename: Tripti
authors.initials: T
authors.lastname: Shrivastava
authors.forename: Garfield A
authors.initials: GA
authors.lastname: Simon
authors.forename: Anne M
authors.initials: AM
authors.lastname: Beck
authors.forename: Tiffany J
authors.initials: TJ
authors.lastname: Swanson
authors.forename: Kathleen
authors.initials: K
authors.lastname: Studnicka
authors.forename: Dorit
authors.initials: D
authors.lastname: Elberg
authors.forename: Kevin
authors.initials: K
authors.lastname: Couloures
authors.forename: Martin A
authors.initials: MA
authors.lastname: Turman
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D055316:Cystatin C / Q000097:blood*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D007677:Kidney Function Tests; D007700:Kinetics; D016014:Linear Models; D010865:Pilot Projects; D006435:Renal Dialysis; D016896:Treatment Outcome; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C