CBF AND OXYGEN-METABOLISM IN HEMODIALYSIS-PATIENTS - EFFECTS OF ANEMIA CORRECTION WITH RECOMBINANT HUMAN EPO

To investigate the effects of anemia correction with recombinant human erythropoietin (rhEPO) on both cerebral blood flow and oxygen metabolism in hemodialysis (HD) patients, the regional cerebral blood flow (rCBF), oxygen extraction (rOEF), and metabolic rate for oxygen (rCMRO2) were measured by positron emission tomography in five HD patients, and the data were compared with eight nondemented controls who had neither anemia nor uremia. In the HD patients, 1,500 U of rhEPO were administered intravenously three times a week to achieve a 10% increase in hematocrit (Hct) as an absolute value. Before rhEPO administration, the hemispheric rCMRO2 in HD patients was 1.48 +/- 0.09 (SE) ml.min-1.100 ml-1, which was significantly lower than that of 2.18 +/- 0.10 in the controls (P < 0.01). In contrast, both rCBF and rOEF were significantly greater in the HD patients than the control, being 40 +/- 3 vs. 32 +/- 3 ml.min-1.100 ml-1 for rCBF(P < 0.02) and 49 +/- 1 vs. 38 +/- 1% for rOEF (P < 0.001). After treatment with rhEPO, Hct rose significantly from 21 +/- 1 to 31 +/- 1% in HD patients (P < 0.001). There were significant reductions in both the hemispheric rCBF to 32 +/- 1 ml.min-1.100 ml-1 (P < 0.01) and rOEF to 42 +/- 1% (P < 0.01). However, the hemispheric rCMRO2 remained low at 1.58 +/- 0.06 ml.min-1.100 ml-1 even after rhEPO treatment. As for the regions of interest, rCMRO2 in the frontal cortex was found to increase slightly but significantly from 1.48 +/- 0.06 to 1.60 +/- 0.05 ml.min-1.100 ml-1 (P < 0.05). These results indicated that cerebral oxygen metabolism was depressed irrespective of the degree of anemia in HD patients, suggesting that anemia per se might not be a major cause for impaired brain metabolism in chronic uremia.