Improvement in anemia by recombinant human erythropoietin in patients with myelodysplastic syndrome and aplastic anemia

Influence of Acetate and Bicarbonate Hemodialysis on the Plasma Erythropoietin Concentration in Patients with Chronic Renal Failure

The present study aimed to assess the influence of acetate (AC) and bicarbonate (BI) hemodialysis with a cuprophane membrane on plasma erythropoietin (EPO) levels in 30 patients with chronic renal failure (CRF). Fifteen patients were severely anemic with an Hct below 30%, while 13 were moderately anemic with an Hct equal to or more than 30%. None had received rHuEPO or ACE inhibitors before the study. Blood samples for EPO and pO2 estimation were withdrawn before and after 1, 2 and 5 h of AC dialysis. In 11 of the patients with an Hct < 30% the same protocol was repeated during BI dialysis. In spite of a significant decrease in pO2 during the first hour of AC dialysis, the plasma EPO concentration decreased significnatly in both severely and moderately anemic CRF patients from 35.4 ± 2.6 to 23.6 ± 3.5 mU/ml after 5 h of hemodialysis (p = 0.0001 by paired t-test) and from 39.5 ± 8.6 to 27.5 ± 8.9 mil/ml (p < 0.01) respectively. In contrast to AC dialysis, Bi dialysis failed to change the plasma EPO concentration (from 32.3 ± 4.1 to 30.3 ± 4.7mil/ml after 5 h of hemodialysis). Conclusions AC but not BI hemodialysis shows a significant suppressive effect on plasma EPO levels in anemic CRF patients in spite of a significant decline in pO2. Factors other than pO2 seem to be involved in the regulation of EPO secretion in CRF patients during AC dialysis.

Erythropoietin

Maintenance of the red cell volume is a fundamental aspect of ensuring oxygen supply to the tissues. The balance between the very dynamic processes of erythropoiesis and erythrocyte loss is precarious and yet normal individuals experience a remarkably constant haematocrit. This is achieved by a very elegant and sensitive homeostatic mechanism which links tissue oxygen delivery to red cell production. The glycoprotein hormone erythropoietin (EPO) is the principle controller of this process. It is now clear that even minor underproduction of EPO will result in anaemia. The most widespread example of this is the anaemia of end-stage renal failure. The pharmacological use of recombinant human EPO (rHuEPO) in this setting is now well established and has had a dramatic impact on the quality of life of patients with renal disease. With the more widespread use of EPO in other clinical conditions and the advent of novel therapeutic approaches, this is an opportune moment to review the physiology and patho-physiology of this fascinating and essential hormone.

Meta-analyses of the effectiveness of erythropoietin for end-stage renal disease and cancer

Anemia, a decreased oxygen-carrying capacity of the blood, develops frequently in patients with end-stage renal disease (ESRD) or cancer. Given the wide variation in clinical response to erythropoietin in the treatment of anemia associated with these diseases, 2 meta-analyses of its effectiveness were undertaken. Databases (MEDLINE and International Pharmaceutical Abstracts) were searched to identify relevant articles. Search terms included erythropoietin, anemia, end-stage renal disease, cancer, multiple myeloma, and myelodysplastic syndrome. Searches were limited to human subjects and the English language. Reference lists of identified articles were reviewed for further articles of interest. The primary author (W.A.M.) selected the articles, and 2 researchers, working independently, extracted the necessary data. Articles had to meet the following criteria to be included in the meta-analyses: (1) Articles must have dealt with treatment of subjects with documented anemia. (2) Studies must have been original research with sample size > or =10. (3) Abstracts could be included if the full research manuscript was unavailable. (4) Patients could not be concurrently receiving other growth factors. (5) The quality of the selected articles must have been assessed by 2 independent researchers. A clinical response to erythropoietin was defined as a 0.06 increase in hematocrit or a 20 g/L increase in hemoglobin. Thirty-nine of the 76 identified articles were included in the meta-analyses. The effectiveness of erythropoietin was calculated at 87% for ESRD, 79% for multiple myeloma, 40% for solid tumor cancer, and 13% for myelodysplastic syndrome. Both subgroup and sensitivity analyses were performed.

Recombinant growth factors

Recombinant human growth factors are expected to have a significant impact on the use of allogeneic blood components. For example, subsequent to the approval of recombinant human erythropoietin, blood transfusions in renal dialysis patients declined substantially. Likewise, myeloid growth factors have reduced infections and hospital stay by promoting hematologic recovery after high dose ablative chemotherapy. The high costs of these agents mandate that their use be limited to settings where they are clinically indicated. The use of growth factors may be monitored at medical centers by hospital transfusion committees. This chapter reviews the emerging clinical guidelines for the use of hematopoietic growth factors.

Serum immunoreactive erythropoietin in patients with idiopathic aplastic and Fanconi's anaemias

In patients with idiopathic aplastic anaemia (n = 34) and Fanconi's anaemia (n = 8), sampled once or on several occasions, serum erythropoietin (Epo) increased with increasing severity of anaemia with apparently similar rates of increase in each group. However, after adjustment for Hb, log Epo values for the Fanconi's anaemics tended to be greater than those for the idiopathic aplastic anaemics (P < 0.01). Erythropoietin concentrations in serum samples from patients with Fanconi's and idiopathic aplastic anaemias tended to be greater than in samples from patients with anaemias from protein energy malnutrition, myelodysplasia and iron deficiency. The results suggest that there is no deficiency of erythropoietin in Fanconi's and idiopathic aplastic anaemias and that if exogenous erythropoietin is of any benefit it would need to be administered in doses large enough to induce a significant increase in log Epo. Results of the study illustrate the need to take account of the assumptions which underlie interpretation of the statistical analysis. Use of erythropoietin values in place of log Epo gives misleading conclusions demonstrable as invalid as the conditions for normality of distribution of the data and homogeneity of variances were not satisfied.