title: The plasma permeability factor in nephrotic syndrome: indirect evidence in pediatric peritoneal dialysis.
abstract: BACKGROUND
  Nephrotic syndrome (NS) in children has been associated with a systemic circulating permeability factor. Therefore, once peritoneal dialysis (PD) has been started, peritoneal protein losses should be higher in the nephrotic than in the non-nephrotic population.
  
  
  OBJECTIVE
  We compared peritoneal protein losses in children with and without NS on PD.
  
  
  METHODS
  Our retrospective 4-year study analyzed Hispanic patients with NS under PD. Data at dialysis entry and 6 months later were compared. Nutritional support was given according to recommended dietary allowances and recommendations from the Kidney Disease Outcomes Quality Initiative. Clinical and biochemical data were obtained, and 24-hour dialysate and urine samples were collected to measure protein losses. Dialysis dose (Kt/V), daily protein intake (DPI), normalized protein equivalent of nitrogen appearance (nPNA), peritoneal equilibration test (PET), and peritonitis rate were determined. All measurements took place at least 4 weeks after resolution of a peritonitis episode. All patients received automated PD using a HomeChoice PD System cycler (Baxter Healthcare Corporation, Deerfield, IL, USA), with an exchange volume of 1100 mL/m(2) and a dextrose concentration of 1.5% - 2.5%. A control group of non-NS children on PD matched by age and sex were also studied. Data are reported as mean ± standard deviation. Differences between groups were calculated using the Mann-Whitney U-test, and p < 0.05 was considered significant.
  
  
  RESULTS
  Each study group consisted of 10 patients [NS patients: 4 boys, mean age of 7.3 ± 4.1 years; control patients: 6 boys, mean age of 7.2 ± 4.7 years (p = nonsignificant)]. In the group with NS, 8 patients were diagnosed by biopsy as having focal segmental glomerulosclerosis, and 2 as having minimal-change disease. At study entry, patients with NS had hourly urinary protein losses of 398 ± 313 mg/m(2) and daily peritoneal protein losses of 3.4 ± 1.9 g/m(2), compared with 29.9 ± 31 mg/m(2) and 1.5 ± 1.1 g/m(2) respectively in the control group (p < 0.05). The same statistical difference was found 6 months later. We observed no statistical differences in PET results, daily exchange volume, and mean dextrose concentration of dialysate. Similarly, no significant between-group differences were observed for Kt/V, DPI, nPNA, and biochemical parameters.
  
  
  CONCLUSIONS
  Hispanic children with NS on PD show higher peritoneal protein losses than do their control counterparts. Such differences could be secondary to increased peritoneal permeability caused by a systemic permeability factor.
authors.affiliation: Division of Pediatric Nephrology, Luis Calvo Mackenna Children's Hospital, University of Chile, Santiago, Chile.
authors.forename: Marta
authors.initials: M
authors.lastname: Azocar
authors.forename: Lily
authors.initials: L
authors.lastname: Quiroz
authors.forename: Angela
authors.initials: A
authors.lastname: Delucchi
authors.forename: Hector
authors.initials: H
authors.lastname: Dinamarca
authors.forename: Marcos
authors.initials: M
authors.lastname: Emilfork
authors.forename: Francisco
authors.initials: F
authors.lastname: Cano
mesh_terms: D002648:Child; D002675:Child, Preschool; D015314:Dialysis Solutions / Q000493:pharmacokinetics*; D004044:Dietary Proteins / Q000378:metabolism; D005260:Female; D005923:Glomerulosclerosis, Focal Segmental; D006630:Hispanic or Latino; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy; D008297:Male; D009404:Nephrotic Syndrome / Q000208:ethnology / Q000378:metabolism / Q000628:therapy*; D010530:Peritoneal Dialysis / Q000379:methods*; D010537:Peritoneum / Q000378:metabolism*; D010539:Permeability; D011506:Proteins / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D015314:Dialysis Solutions; D004044:Dietary Proteins; D011506:Proteins