Folic acid treatment of hyperhomocysteinemia in dialysis patients.

We measured fasting total plasma homocysteine (Hcy) in 10 chronic hemodialysis (HD) and 10 chronic peritoneal dialysis (PD) patients. Mean (+/- SEM) Hcy was 55.7 +/- 10.1 and 50.5 +/- 14.3 mumol/l, respectively (normal range 6-19 mumol/l). Hemodialysis treatment lowered Hcy by about 30%. Daytime Hcy concentrations were stable in the PD patients. Six weeks of treatment with folic acid (FA) significantly lowered Hcy in HD and PD patients to 24.0 +/- 1.8 and 21.0 +/- 3.6 mumol/l, respectively. After withdrawal, Hcy rose slowly, in parallel with the gradually decreasing plasma FA concentrations, which were greatly elevated during treatment. Chronic treatment with FA of another group of patients showed a similar effect on Hcy. Preliminary results of oral methionine loading in chronic dialysis patients were compatible with delayed homocysteine metabolism via the transsulfuration pathway. Further studies on the optimal treatment of hyperhomocysteinemia in chronic dialysis patients are needed.