title: Influence of dialysis techniques and alternate vitamin supplementation on homocysteine levels in patients with known MTHFR genotypes.
abstract: BACKGROUND
  Treatment with folic acid and vitamin B12 appears capable of reducing total plasma homocysteine levels (tHcy), but it is unknown whether vitamin B12 alone reduces tHcy values. In this study we investigate the effects of alternate vitamins supplementation on homocysteine levels in patients treated by diffusive and convective dialysis techniques.
  
  
  METHODS
  74 patients were randomized blindly into two groups of 37 subjects each. The first group was treated initially with vitamin B12 for 2 months and with folic acid for the following 2 months. The second group was treated initially with folic acid. A wash out period of 2 months followed the treatment in both groups.
  
  
  RESULTS
  Total homocysteine levels decreased in both groups following the alternate vitamins therapy and dialysis, without significant difference between diffusive and convective techniques. Surprisingly, after the wash-out period, tHcy increased remarkably, regardless of the dialysis procedure used. At the end of the study, folate levels showed a higher reduction with haemodialysis compared to haemodiafiltration. In contrast, vitamin B12 levels showed a significant increase using diffusive haemodialysis, confirming a decisive role of membrane performance.
  
  
  CONCLUSIONS
  In conclusion we show for the first time that, even if total homocysteine levels decreased in both dialysis procedures, the convective techniques demonstrate a superior capacity on the reduction of tHcy levels compared to the diffusive method. Moreover, the lower depletion of vitamin B12 by diffusive techniques could determine a higher reduction of folate levels, demonstrating the decisive role of the membrane performance in the treatment of this patients.
authors.affiliation: Department of Laboratory Medicine, Tor Vergata University Hospital, Viale Oxford 81, 00133, Rome, Italy, mariarita.dessi@ptvonline.it.
authors.forename: Mariarita
authors.initials: M
authors.lastname: Dessì
authors.forename: Gianna
authors.initials: G
authors.lastname: Di Giovamberardino
authors.forename: Massimo
authors.initials: M
authors.lastname: Pieri
authors.forename: Annalisa
authors.initials: A
authors.lastname: Noce
authors.forename: Rossella
authors.initials: R
authors.lastname: Zenobi
authors.forename: Nicola
authors.initials: N
authors.lastname: Di Daniele
authors.forename: Anna
authors.initials: A
authors.lastname: Pastore
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D005838:Genotype; D017583:Hemodiafiltration; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000235:genetics* / Q000378:metabolism / Q000628:therapy*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D006435:Renal Dialysis / Q000379:methods*; D014805:Vitamin B 12 / Q000627:therapeutic use; D014815:Vitamins / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D014815:Vitamins; D006710:Homocysteine; D005492:Folic Acid; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12