Beneficial and adverse effects of correction of anaemia by recombinant human erythropoietin in patients on maintenance haemodialysis

Quality of Life Improvements in Capd Patients Treated with Subcutaneously Administered Erythropoietin for Anemia

Twenty -two continuous ambulatory peritoneal dialysis (CAPD) patients, mean age 48 years, at 3 U.K. renal units were assessed with the Nottingham Health Profile (N HP) before and after treatment with recombinant human erythropoietin (r-HuEPO). Mean (SD) hemoglobin (Hb) at baseline was 7.5 (1.0) gIn/dl and 10.8 (1.5) gIn/dl at retest. There were significant improvements in energy (p<0.0001), social life (p<0.005), relationships at home (p<0.05) and leisure pursuits (p<0.05). Twelve patients, mean age 51 years, who had already completed more than 9 months on r-HuEPO treatment were reassessed to determine the changes sustained. Mean (SD) Hb at second retest was 12.8 (1.3) gm/dl. Improvement in energy continued to be significant, and emotional wellbeing showed further improvement. Problems with household tasks, which had not shown significant improvement at Test B, were now considerably reduced (p=0.016). The study showed far-reaching benefits similar to those reported in hemodialysis patients, in a population with a higher mean age and higher potential coexisting illness or disability than most reported hemodialysis studies.

Effect of Erythropoietin Therapy on Diet and Dialysis Clearances in Hemodialysis Patients

Treatment of renal anemia with recombinant human erythropoietin in chronic hemodialysis patients has been reported to lead to increased appetite, and in several studies, to an increase in predialysis serum urea, potassium and creatinine values. We recorded dietary intake, and dialysis clearances for creatinine, urea and uric acid in a group of 12 anemic hemodialysis patients treated with recombinant erythropoietin (epoetin beta). A gradual increase was noted in dietary intake of calories, carbohydrate and sodium during the study period, attaining statistical significance after 10–12 months of therapy. A trend toward increased dietary intake of protein, lipid and potassium was observed, but the differences did not achieve statistical significance. Although a trend toward decreased dialysis clearance at higher hematocrits was found for creatinine clearances did not change significantly for any of the solutes examined, and linear regression analysis did not demonstrate a strong relationship between dialyzer clearance and hematocrit values within the range observed in this study.

The Effect of Hemodialysis and Acetate-Free Biofiltration on Anemia

The authors monitored, for a period of 12 months, anemia-, nutrition-, and free radical-related parameters and the rHuEPO dose required to maintain target hemoglobin (Hb) in 20 patients with chronic renal failure. Ten patients each were randomized for treatment by either acetate-free biofiltration (AFB) or low-flux hemodialysis (HD). At baseline, Hb levels were 102±2 (AFB) vs. 98±2 g/L (HD) (not significant difference, NS), the rHuEPO dose was 4050±976 vs. 5100±1538 IU/week (NS). Compared with baseline and with HD, lower rHuEPO doses were required during AFB at months 8, 9, 10 and 11, and 12 when they were 2100±510 (AFB) vs. 6000±1153 (HD), p=0.008. Prealbumin, transferrin and cholinesterase levels rose in the AFB group. Kt/V, albumin, transferrin saturation, aluminium, bicarbonate in serum, superoxide dismutase and glutathione peroxidase in erythrocytes, and malondialdehyde and antioxidant capacity in plasma did not differ between the AFB and HD groups. In terms of anemia control, AFB using an AN69 membrane was found to be more advantageous than low-flux HD, AFB improves some nutritional parameters. The compared methods do not differ in their effect on lipid peroxidation and the antioxidant system. (Int J Artif Organs 2000; 23: 173–80)

Effect of chronic and short-term erythropoietin treatment on random flap survival in rats: an experimental study

OBJECTIVE

The use of perioperative erythropoietin (EPO) therapy is gaining popularity to avoid blood transfusion and correct anemia in head and neck cancer surgery. The purpose of the study was to determine the effect of various doses and durations of EPO treatment on random flap survival.

STUDY DESIGN

A McFarlane type random and musculocutaneous (3 x 10 cm) flap were elevated on the dorsum of each rat.

METHODS

Eighty-four male Albino rats were randomly assigned into seven groups (2 animals in each group): group I, control animals receiving placebo; group II, chronic EPO injections (50 U/kg); group III, chronic EPO injections (100 mg/kg); group IV, chronic EPO injections (150 mg/kg); group V, short-term EPO injections (50 mg/kg); group VI, short-term EPO injections (100 mg/kg); and group VII, short-term EPO injections (150 mg/kg). Rats in groups II to IV began to receive EPO 3 weeks (thrice weekly) before the construction of flaps, and rats in groups V to VII received EPO after flap elevation for 1 week (thrice) subcutaneously. Following 7 days of recovery, the area of flap survival was measured. Hematocrit and systolic blood pressure were followed weekly in all groups.

RESULTS

Erythropoietin increased the hematocrit levels and systolic blood pressure in all groups, but significant increases were noted only in the long-term treatment groups. There was a significant increase in distal necrosis of random skin flaps after long-term EPO treatment (P <.05). However, short-term low and therapeutic doses of EPO improved flap survival significantly (P <.05).

CONCLUSIONS

Long-term EPO treatment might have impaired flap survival because of direct or prostaglandin-mediated vasoconstriction, endothelin-induced hypertension, increased peripheral vascular resistance, hyperviscosity, and increased thrombosis. However, EPO might have enhanced flap survival because of its antioxidant effect and modulation of nitric oxide levels. Effects of EPO are controversial, and further research is necessary to delineate the dose and duration relationship and the exact mechanism of action on flap viability.

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.

Current status of prevention, diagnosis, and management of coronary artery disease in patients with kidney failure

BACKGROUND

Patients with kidney failure have a heavy burden of coronary artery disease. The results of preventive, diagnostic, and therapeutic measures developed in nonuremic populations cannot automatically be extrapolated to this unique group of patients.

METHODS AND RESULTS

Articles were reviewed if they contained English language text or an abstract identified by MEDLINE search from 1980 to 1999, supplemented by manual review of bibliographies of published articles and abstract issues of national cardiology meetings, studies on diagnostic techniques, risk modification measures, pharmacologic agents, and coronary revascularization procedures in patients with uremia. Descriptive and quantitative data as appropriate were extracted. Lipid-lowering agents may be safely administered to uremic patients. Direct evidence of lipid lowering in this population is not available and is not likely to be forthcoming. Erythropoietin therapy is effective in reversing the cardiovascular perturbations of uremic anemia, but an approach of normalizing the hematocrit cannot be recommended. Glycoprotein IIb/IIIa inhibitors used in acute coronary syndromes require downward dose adjustment or are contraindicated. Thrombolytic agents are underutilized in the management of myocardial infarction. Noninvasive testing is less accurate than in nonuremic populations. Coronary revascularization offers relative clinical advantages over medical therapy similar to non-kidney failure populations, even though the results in uremic patients is significantly less favorable than for nonuremic patients. Stenting is the preferred revascularization approach, and conventional balloon percutaneous transluminal coronary angioplasty the least favorable.

CONCLUSIONS

Many but not all of the benefits of therapies developed in nonuremic patients extend to patients with kidney failure. Physicians should be familiar with the advantages and limitations of each of these modalities in this population.

Dose escalation induces tolerance to side-effects of erythropoietin in a patient with dialysis anaemia: case report

A 51-year-old woman began haemodialysis for chronic renal failure in February 1981. Symptomatic anaemia required treatment with recombinant human erythropoietin (rHuEPO) in February 1990 (3000 IU, twice weekly, intravenously). She developed influenza-like symptoms and treatment was withdrawn. In June 1994 rHuEPO was resumed at a very low dose of 100 IU subcutaneously three times weekly, and was increased gradually to 500 IU, without inducing any side-effects. At this dose the haematocrit was maintained at 22.0-25.0% and the symptoms of anaemia improved. In patients like ours, with influenza-like symptoms caused by rHuEPO therapy, dose escalation starting from an ultra-low dose may be effective in avoiding side-effects.

Investigation of the influenza-like symptoms associated with recombinant human erythropoietin therapy

The mechanism by which fever and influenza-like symptoms occur, after the administration of recombinant human erythropoietin (rHuEPO) to patients on continuous ambulatory peritoneal dialysis, was investigated. Peripheral blood mononuclear cells, obtained from two patients with fever and/or influenza-like symptoms related to the administration of rHuEPO for the treatment of anaemia were cultured with or without rHuEPO (100, 200, and 300 U/ml). Production of interleukin-1 beta and tumour necrosis factor-alpha was higher in cultures with rHuEPO than in cultures without rHuEPO, although the dose relationships were not clear. These findings suggest that increased production of interleukin-1 beta and tumour necrosis factor-alpha 1, induced by administration of rHuEPO, may cause fever and influenza-like symptoms.

Anemia of renal failure. Use of erythropoietin

Chronic renal failure is almost invariably accompanied by symptomatic anemia. It has been demonstrated that the primary cause of this anemia is inadequate production of erythropoietin by the diseased kidneys. The isolation of erythropoietin, followed by the cloning and expression of the human erythropoietin gene, made possible clinical trials of rHuEPO in uremic patients. rHuEPO produced dramatic increases in the hematocrit in almost all patients treated and also ameliorated many symptoms, such as lethargy, dizziness, and poor appetite, that had long been attributed to the effect of uremic toxins. Adverse effects of treatment with rHuEPO noted in the early clinical trials included hypertension, seizures, arteriovenous fistula or shunt thrombosis, and hyperkalemia. Further study of rHuEPO has shown that many of these side effects may be no more frequent in patients receiving rHuEPO than in other uremic patients not receiving rHuEPO. Reduction of the rHuEPO dosage and subcutaneous administration produce less rapid increases in the hematocrit and may lessen the incidence and severity of these side effects. rHuEPO therapy places great demands on both the body's iron stores and the capacity to rapidly transfer iron from storage sites to the erythroid progenitor cells. Thus, almost all patients treated with rHuEPO become iron deficient and require oral or parenteral iron replacement. Response to rHuEPO in uremic patients is diminished if the anemia is complicated by iron deficiency, inflammatory disorders, aluminum overload, or deficiency of folate or vitamin B12. rHuEPO therapy is safe and effective in the treatment of the anemia of chronic renal failure. The use of rHuEPO leads to enhanced quality of life and eliminates the need for red cell transfusions. In addition to hemodialysis patients, predialysis patients and those on CAPD benefit from and are candidates for rHuEPO therapy.

Erythropoietin treatment and plasma levels of corticotropin-releasing hormone, delta sleep-inducing peptide and opioid peptides in hemodialysis patients

An improvement of quality of life and objective brain function has been reported in patients receiving regular hemodialysis treatment (RDT) during treatment with recombinant human erythropoietin (r-huEPO). The mechanisms explaining this improvement are unknown. In this study the plasma levels of peptides known to be involved in CNS functions, namely corticotropin-releasing hormone, delta sleep-inducing peptide, beta-endorphin, methionine-enkephalin, beta-lipotropin and alpha-melanocyte-stimulating hormone, were measured by radioimmunoassay in seven stable RDT patients before the start of r-huEPO therapy and during 28 weeks' treatment. All patients responded with significantly increased hemoglobin concentrations. An improvement of well-being, state of mood and physical fitness was reported by the patients. There were no significant changes during the study in the plasma concentrations of any of the peptides measured. However, as the plasma levels of neuropeptides will not necessarily reflect the local concentrations in the vicinity of the nerve terminals, changes in the intracerebral concentrations of these peptides might occur in response to r-huEPO.

Renal transplantation in r-HuEPO-treated patients

After sporadic reports of renal graft artery thromboses, prophylaxis against thrombosis (PAT) was given to all of our r-HuEPO-treated patients (n = 35) during a period of 2 years. No thromboembolic events (TEE) occurred in the r-HuEPO-treated group receiving PAT. However, the PAT-protocol (500 ml dextran on days 0, 1, 3 and 5, followed by low doses of aspirin, 160-250 mg daily) resulted in a 54.3% incidence of bleeding complications, of which 22.9% were major (i.e., necessitating multiple transfusions or invasive procedures). A group of renal graft recipients (n = 83), who were not treated with r-HuEPO and were not given PAT, showed a 10.8% incidence of bleeding complications of which 2.4% major. Two cases of TEE were noted in the untreated group. The difference in bleeding complications between the two groups was statistically significant (0.025 > P > 0.01). The difference in TEE between the groups was not significant. We found no difference between the groups with regard to early and late graft function and the incidence of acute rejections. In summary, r-HuEPO treatment did not influence the prognosis in renal graft recipients. The use of PAT in the r-HuEPO-treated group resulted in a high incidence of bleeding complications. In consequence, we have abandoned the routine use of PAT in this patient group.

Low dose erythropoietin in maintenance haemodialysis: improvement in quality of life and reduction in true cost of haemodialysis

Human recombinant erythropoietin (r-HuEPO) improves quality of life in patients on maintenance haemodialysis, but the haemoglobin (Hb) level necessary to achieve this improvement is unknown. In this study, quality of life, functional capacity and symptoms of 28 haemodialysis patients with an initial Hb of 67 +/- 2 (mean +/- SEM) g/L were assessed after 0, 6 and 12 months of r-HuEPO, the dose of which was titrated to achieve a stable Hb of between 90 and 100 g/L. At six and 12 months Hb was 97 +/- 2 and 93 +/- 2 g/L, and mean r-HuEPO dose between three and six, and between nine and 12 months was 88 +/- 6 and 62 +/- 9 U/kg/week intravenously respectively. There was a significant improvement in level of activity and satisfaction with various aspects of life, and a reduction in fatigue, weakness, dyspnoea, angina and restless legs. Patients were able to walk 50% further in six minutes. The improvement in quality of life and function was similar to that reported from other centres whose target Hb was between 100 and 120 g/L, and where the r-HuEPO dose was 75% higher than in this study. Costs of r-HuEPO therapy were assessed. The drug itself costs +A3681/yr/patient, to which was added the estimated cost of additional dialyses and medications, bringing the total to +A5177/yr/patient. There was, however, a reduction in both hospitalisation by 8.3 days/yr/patient and medical consultation by 3.9 hours/yr/patient. Five patients commenced full-time work, one took up full-time study aimed at finding work, three transferred to home haemodialysis and six fewer patients drew social security benefits. The net cost saving from using low dose r-HuEPO was more than +A1,000/yr/patient.

Recombinant human erythropoietin

Erythropoietin is produced mainly by the kidneys and stimulates erythropoiesis in the bone marrow. Chronic renal failure is characterized by anemia, which is principally caused by erythropoietin deficiency. Recombinant human erythropoietin (r-hEPO) corrects the anemia of chronic renal disease and improves patient well-being, exercise tolerance, and cognitive function. The clinical pharmacology, efficacy, safety, and tolerance of r-hEPO are presented. Four major studies attest to r-hEPO's efficacy in the treatment of anemia of chronic renal disease and document potential toxicities of hypertension, iron deficiency, thrombosis, and bone pain. Careful attention to the extent of correction of the hematocrit, increased heparinization during hemodialysis therapy, and compliance with dietary restrictions may minimize the incidence and severity of adverse reactions. Resistance to r-hEPO may be due to iron deficiency, aluminum toxicity, or inflammation, including infection. Potential future uses of r-hEPO include the treatment of various other anemias, such as those seen in sickle cell anemia, rheumatoid arthritis, and autologous blood donation. Controlled clinical studies in these areas have not been reported.

Recombinant human erythropoietin in nephrology

rEPO therapy provides a unique opportunity to correct anemia in end-stage renal failure patients. Complete correction of the anemia, although possible, has some obvious disadvantages over a partial correction with a target hemoglobin of 10-13 g/dl or a hematocrit of 30-35%, respectively. Unresponsiveness to rEPO seems to be rare; in most cases the predicted hemoglobin increase could be seen as soon as an underlying iron deficiency was treated adequately. Blood loss and aluminum toxicity are the next most frequent reasons for an inadequate response to rEPO. Hypertension (and its complications) as well as fistula clotting are the most important side-effects which require close attention when patients at risk for these complications are treated with rEPO.