HOMOCYSTEINE AND FOLATE CONCENTRATIONS IN BLOOD FROM PATIENTS TREATEDWITH HEMODIALYSIS

Plasma homocysteine and plasma and erythrocyte folate concentrations b efore and after hemodialysis were measured in 31 patients with ESRD. H omocysteine and folate were measured by HPLC-fluorometric and microbio logical methods, respectively. The mean plasma homocysteine level decl ined from 36.8 to 24.2 mu mol/L during hemodialysis, indicating that h omocysteine can be partly removed by hemodialysis (P < 0.0001). Mean p lasma folate concentration before hemodialysis was 46.4 nmol/L and dec reased to 25.9 nmol/L after hemodialysis (P < 0.0001), whereas mean er ythrocyte folate concentration did not change (1295 and 1385 nmol/L be fore and after hemodialysis, respectively). Plasma folate concentratio ns showed a significant negative correlation with homocysteine concent rations before and after hemodialysis (r = -0.53, P < 0.003, and r = - 0.59, P < 0.001, respectively). Furthermore, there were significant ne gative correlations between plasma homocysteine and erythrocyte folate concentrations both before (r = -0.60, P < 0.0005) and after hemodial ysis (r = -0.49, P < 0.005). All patients had homocysteine concentrati ons over 12.0 mu mol/L before hemodialysis, and only three had homocys teine concentrations lower than 12.0 mu mol/L after hemodialysis. Alth ough significant correlations existed between homocysteine and folate concentrations, the majority of the patients in this study appeared to have adequate folate nutriture as assessed by blood folate concentrat ions. It remains to be determined whether patients with ESRD have an a ltered homocysteine metabolism.