Long-term reduction of plasma homocysteine levels by super-flux dialyzers in hemodialysis patients

Background. Hyperhomocysteinemia is an independent risk factor for cardiova scular disease in chronic hemodialysis (CHD) patients. Treatment with folic acid normalizes total homocysteine (tHcy) in only a minority of the patien ts. The present investigation has been conducted to study the influence of various dialyzers with different flux characteristics on the reduction of t Hcy in the long term. Methods. Total Hey, folate, vitamin B-6, vitamin B-12, and albumin levels w ere assessed prospectively in 10 patients undergoing HD with high-flux poly sulfon (PS; F 60) and 20 patients with super-flux dialyzers (N = 10 PS, F 5 00S; N = 10 CTA, Tricea 150G). Blood samples were collected before hemodial ysis both at the beginning of the study and after 12 weeks. Results. At baseline, all the groups showed similar tHcy levels. During hig h-flux dialysis, tHcy remained stable. In contrast, during dialysis with bo th super-flux modalities, tHcy decreased significantly (F 500S week 1, 29.6 +/- 9.9 mu mol/L, and week 12, 21.5 +/- 8.5 mu mol/L, P = 0.007; Tricea 15 0G week 1, 24.4 +/- 8.7 mu mol/L, and week 12, 15.3 +/- 3.7 mu mol/L, P = 0 .008). The difference between high-flux and super-flux dialyzers was highly significant (mean: high-flux increase 15.6%, super-flux decrease 33.3%, P = 0.001). Multivariate analysis showed a significant effect of super-flux d ialysis on tHcy (P = 0.001), independently of the previously mentioned vari ables. Conclusions. Our findings clearly show that both types of super-flux dialyz ers reduced tHcy significantly. As the molecular weight of free homocystein e is less than 268 D, the most likely explanation seems to be the removal o f uremic toxins with inhibitory activities against enzymes involved in the extrarenal homocysteine metabolism.