title: Fibroblast Growth Factor 21 (FGF-21) in Peritoneal Dialysis Patients: Natural History and Metabolic Implications.
abstract: BACKGROUND
  Human fibroblast growth factor 21 (FGF-21) is an endocrine liver hormone that stimulates adipocyte glucose uptake independently of insulin, suppresses hepatic glucose production and is involved in the regulation of body fat. Peritoneal dialysis (PD) patients suffer potential interference with FGF-21 status with as yet unknown repercussions.
  
  
  OBJECTIVE
  The aim of this study was to define the natural history of FGF-21 in PD patients, to analyze its relationship with glucose homeostasis parameters and to study the influence of residual renal function and peritoneal functional parameters on FGF-21 levels and their variation over time.
  
  
  METHODS
  We studied 48 patients with uremia undergoing PD. Plasma samples were routinely obtained from each patient at baseline and at 1, 2 and 3 years after starting PD therapy.
  
  
  RESULTS
  Plasma FGF-21 levels substantially increased over the first year and were maintained at high levels during the remainder of the study period (253 pg/ml (59; 685) at baseline; 582 pg/ml (60.5-949) at first year and 647 pg/ml (120.5-1116.6) at third year) (p<0.01). We found a positive correlation between time on dialysis and FGF-21 levels (p<0.001), and also, those patients with residual renal function (RRF) had significantly lower levels of FGF-21 than those without RRF (ρ -0.484, p<0.05). Lastly, there was also a significant association between FGF-21 levels and peritoneal protein losses (PPL), independent of the time on dialysis (ρ 0.410, p<0.05).
  
  
  CONCLUSIONS
  Our study shows that FGF-21 plasma levels in incident PD patients significantly increase during the first 3 years. This increment is dependent on or is associated with RRF and PPL (higher levels in patients with lower RRF and higher PPL). FGF-21 might be an important endocrine agent in PD patients and could act as hormonal signaling to maintain glucose homeostasis and prevent potential insulin resistance. These preliminary results suggest that FGF-21 might play a protective role as against the development of insulin resistance over time in patients undergoing a continuous glucose load.
authors.affiliation: Department of Nephrology, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: González
authors.affiliation: Department of Endocrinology, University Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Díez
authors.affiliation: Department of Nephrology, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: M Auxiliadora
authors.initials: MA
authors.lastname: Bajo
authors.affiliation: Department of Nephrology, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: del Peso
authors.affiliation: Department of Endocrinology, University Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Grande
authors.affiliation: Department of Biochemistry, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: Olaia
authors.initials: O
authors.lastname: Rodríguez
authors.affiliation: Biostatistics Section, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: Mariana
authors.initials: M
authors.lastname: Díaz-Almirón
authors.affiliation: Department of Endocrinology, University Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Iglesias
authors.affiliation: Department of Nephrology, La Paz University Hospital, IdiPAZ, FRIAT-IRSIN, REDinREN, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Selgas
mesh_terms: D001786:Blood Glucose / Q000032:analysis; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood* / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D013997:Time Factors; D014511:Uremia / Q000628:therapy
chemical_list: D001786:Blood Glucose; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors; D005947:Glucose