Supplementation with vitamin B12 decreases homocysteine and methylmalonic acid but also serum folate in patients with end-stage renal disease.
Hyperhomocysteinemia is frequently found in patients with end-stage renal disease (ESRD). Plasma total homocysteine (tHcy) concentrations may be reduced by supplementation with folic acid or combinations of folic acid, vitamin B12, and vitamin B6. Supplementation studies with vitamin B12 alone in patients with ESRD have not yet been published. In this study, we investigated the effects of intravenous injection of cyanocobalamin (1 mg/wk for 4 weeks) in ESRD patients (N = 14) with low serum cobalamin concentrations (<180 pmol/L). All patients had elevated levels of plasma tHcy, methylmalonic acid (MMA), and cystathionine before supplementation. After supplementation, plasma tHcy and MMA decreased 35% and 48%, respectively; however, cystathionine levels were unchanged. The extent of the plasma tHcy reduction tended to be influenced by the C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR). Serum cobalamin increased significantly upon supplementation, whereas serum folate levels were substantially reduced by 47%. In contrast, red blood cell (RBC) folate was unchanged. This study shows that vitamin B12 supplementation effectively decreases both MMA and plasma tHcy in ESRD patients with low B12 levels. Furthermore, it illustrates the close interrelation between vitamin B12 and folate metabolism.
Dierkes
J
J
Institute of Clinical Chemistry and Nephrology Clinic, University Hospital Magdeburg, Germany.
Domröse
U
U
Ambrosch
A
A
Schneede
J
J
Guttormsen
A B
AB
Neumann
K H
KH
Luley
C
C
D000328:Adult; D000368:Aged; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005493:Folic Acid Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D005838:Genotype; D006710:Homocysteine / Q000037:antagonists & inhibitors / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000188:drug therapy*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008764:Methylmalonic Acid / Q000037:antagonists & inhibitors / Q000097:blood*; D008875:Middle Aged; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*
D005493:Folic Acid Antagonists; D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12