title: Effect of dialyser membrane pore size on plasma homocysteine levels in haemodialysis patients.
abstract: BACKGROUND
  Hyperhomocysteinaemia is a putative risk factor for atherothrombotic cardiovascular disease in the haemodialysis population. High-dose vitamin B therapy does not entirely normalize elevated plasma total homocysteine (tHcy) levels in haemodialysis patients. Alternative therapies to reduce tHcy further are therefore required. Modifications of the dialysis regimen may result in a better removal of Hcy. We examined the effect of dialyser membrane pore size on tHcy levels in vitamin-replete chronic haemodialysis patients.
  
  
  METHODS
  Forty-five haemodialysis patients were dialysed during 4 weeks with a low-flux, a high-flux and a super-flux membrane, in random order. Pre-dialysis tHcy was determined at baseline and every 4 weeks. In 18 patients, plasma tHcy before and after dialysis and dialysate tHcy concentrations were measured.
  
  
  RESULTS
  Pre-dialysis tHcy decreased significantly during 4 weeks super-flux dialysis (-14.6 +/- 2.8%), whereas it remained stable during high-flux (+0.5 +/- 2.4%) and low-flux dialysis (+1.7 +/- 3.2%). The homocysteine reduction ratio was not different for the three membranes: 0.39 +/- 0.03 for the super-flux, 0.47 +/- 0.02 for the high-flux and 0.39 +/- 0.02 for the low-flux dialyser. The amount of Hcy recovered in the dialysate during a single dialysis session was also similar: 117.5 +/- 3.6 micro mol during super-flux, 95.3 +/- 11.5 micro mol during high-flux and 116.5 +/- 11.6 micro mol during low-flux dialysis.
  
  
  CONCLUSIONS
  Super-flux dialysis significantly lowers tHcy in chronic haemodialysis patients. Improved removal of middle-molecule uraemic toxins with inhibitory effects on Hcy-metabolizing enzymes, rather than better dialytic clearance of Hcy itself, may explain the beneficial effect of the super-flux membrane.
authors: Renal Unit and Department of Clinical Chemistry, AZ Sint-Jan AV, Ruddershove 10, B-8000 Brugge, Belgium. an.devriese@azbrugge.be
authors: An S
authors: AS
authors: De Vriese
authors: Michel
authors: M
authors: Langlois
authors: Dirk
authors: D
authors: Bernard
authors: Inge
authors: I
authors: Geerolf
authors: Lut
authors: L
authors: Stevens
authors: Johan R
authors: JR
authors: Boelaert
authors: Mario
authors: M
authors: Schurgers
authors: Ervé
authors: E
authors: Matthys
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D006435:Renal Dialysis / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D006710:Homocysteine