title: β-trace protein is highly removed during haemodialysis with high-flux and super high-flux membranes.
abstract: Serum β-trace protein (βTP, MW 23-29 kDa) is a marker of GFR impairment in renal patients. Recent papers propose to predict residual renal function (RRF) in maintenance haemodialysis (MHD) patients from serum concentrations of βTP and other small proteins, avoiding the collection of urine. Few data are available on the removal of βTP in patients treated with dialysis membranes with different flux characteristics. The aim of this study was to evaluate the effects of haemodialysis with low-flux, high-flux and super high-flux membranes on serum concentrations of ßTP in MHD patients with null RRF.
  
  
  
  Serum ßTP concentrations were measured before and after the first dialysis of the week in 51 MDH patients treated by low-flux (n = 24), high-flux (n = 17), or super high-flux (n = 10) membranes. The removal of β2-microglobulin (β2M, MW 11.8), cystatin C (Cys, MW 13.3), urea and creatinine was also analyzed.
  
  
  
  Low-flux membranes did not remove βTP, β2M and Cys whose concentration increased at the end of dialysis. High-flux membrane removed more efficiently β2M and Cys than ßTP. Super high-flux membrane had the highest efficiency to remove ßTP: mean reduction ratio (RR) 53.4%, similar to β2M (59.5%), and Cys (62.0%).
  
  
  
  In conclusion, the plasma clearance of small proteins and particularly of βTP is dependent from the permeability of the dialysis membranes Therefore, the reliability of the formulas proposed to predict RRF from serum βTP and other LMWP may be affected by the different permeability of the dialysis membranes.
authors.affiliation: Division of Nephrology, Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, I-56126, Pisa, Italy. carlo.donadio@med.unipi.it.
authors.forename: Carlo
authors.identifier: 0000-0003-1124-5129
authors.initials: C
authors.lastname: Donadio
authors.affiliation: Division of Nephrology, Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, I-56126, Pisa, Italy.
authors.forename: Danika
authors.initials: D
authors.lastname: Tognotti
authors.affiliation: Laboratory of Clinical Pathology, Department of Translational Research, University of Pisa, Pisa, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Caponi
authors.affiliation: Laboratory of Clinical Pathology, Department of Translational Research, University of Pisa, Pisa, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Paolicchi
mesh_terms: D000181:Acrylonitrile; D000368:Aged; D000369:Aged, 80 and over; D000476:Alkanesulfonates; D002482:Cellulose / Q000031:analogs & derivatives; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D011108:Polymers; D006435:Renal Dialysis / Q000295:instrumentation*; D013450:Sulfones; D014508:Urea / Q000097:blood; D001613:beta 2-Microglobulin / Q000097:blood
chemical_list: D000476:Alkanesulfonates; D055316:Cystatin C; D054834:Lipocalins; D008567:Membranes, Artificial; D011108:Polymers; D013450:Sulfones; D001613:beta 2-Microglobulin; C017662:polysulfone P 1700; D014508:Urea; D002482:Cellulose; C024671:cellulose triacetate; C026170:cellulose diacetate; C056081:methallyl sulfonate; D003404:Creatinine; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D000181:Acrylonitrile
keywords: Low-molecular weight proteins; Maintenance haemodialysis; Permeability of dialysis membranes; Residual renal function; β-trace protein