Kidney function and plasma copeptin levels in healthy kidney donors and autosomal dominant polycystic kidney disease patients.

Abstract

BACKGROUND AND OBJECTIVES:

Plasma copeptin, a marker of arginine vasopressin, is elevated in patients with autosomal dominant polycystic kidney disease and predicts disease progression. It is unknown whether elevated copeptin levels result from decreased kidney clearance or as compensation for impaired concentrating capacity. Data from patients with autosomal dominant polycystic kidney disease and healthy kidney donors before and after donation were used, because after donation, overall GFR decreases with a functionally normal kidney.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:

Data were obtained between October of 2008 and January of 2012 from healthy kidney donors who visited the institution for routine measurements predonation and postdonation and patients with autosomal dominant polycystic kidney disease who visited the institution for kidney function measurement. Plasma copeptin levels were measured using a sandwich immunoassay, GFR was measured as (125)I-iothalamate clearance, and urine concentrating capacity was measured as urine-to-plasma ratio of urea. In patients with autosomal dominant polycystic kidney disease, total kidney volume was measured with magnetic resonance imaging.

RESULTS:

Patients with autosomal dominant polycystic kidney disease (n=122, age=40 years, men=56%) had significantly higher copeptin levels (median=6.8 pmol/L; interquartile range=3.4-15.7 pmol/L) compared with donors (n=134, age=52 years, men=49%) both predonation and postdonation (median=3.8 pmol/L; interquartile range=2.8-6.3 pmol/L; P<0.001; median=4.4 pmol/L; interquartile range=3.6-6.1 pmol/L; P<0.001). In donors, copeptin levels did not change after donation, despite a significant fall in GFR (from 105 ± 17 to 66 ± 10; P<0.001). Copeptin and GFR were significantly associated in patients with autosomal dominant polycystic kidney disease (β=-0.45, P<0.001) but not in donors. In patients with autosomal dominant polycystic kidney disease, GFR and total kidney volume were both associated significantly with urine-to-plasma ratio of urea (β=0.84, P<0.001; β=-0.51, P<0.001, respectively).

CONCLUSIONS:

On the basis of the finding in donors that kidney clearance is not a main determinant of plasma copeptin levels, it was hypothesized that, in patients with autosomal dominant polycystic kidney disease, kidney damage and associated impaired urine concentration capacity determine copeptin levels.

• Authors: Debbie Zittema, Else van den Berg, Esther Meijer, Wendy E Boertien, Anneke C Muller Kobold, Casper F M Franssen, Paul E de Jong, Stephan J L Bakker, Gerjan Navis, Ron T Gansevoort
• Journal: Clinical journal of the American Society of Nephrology : CJASN (Clin J Am Soc Nephrol) Vol. 9 Issue 9 Pg. 1553-62 (Sep 05 2014) ISSN: 1555-905X [Electronic] United States
• PMID: 24993447 (Publication Type: Journal Article)
• Copyright: Copyright © 2014 by the American Society of Nephrology.

Chemical References

• Glycopeptides
• copeptins

Topics

• Adult
• Female
• Glycopeptides (blood)
• Humans
• Kidney (physiology)
• Kidney Function Tests
• Male
• Middle Aged
• Polycystic Kidney, Autosomal Dominant (blood, physiopathology)
• Severity of Illness Index
• Tissue Donors