Anemia of renal failure. Use of erythropoietin

Current controversies in the use of haemoglobin A1c

Haemoglobin A(1c) (HbA(1c)) has recently been adopted by the World Health Organization into its recommended criteria for diabetes diagnosis. Much debate continues regarding the relative benefits and potential disadvantages surrounding the use of HbA(1c) for this purpose. There is a lack of consensus as to whether this alteration to the definition of diabetes is a step forward or whether it could add further confusion and ambiguity to the debate on the method and criteria for the diagnosis of this globally important disease. This review provides a comprehensive overview of the current issues surrounding how HbA(1c) is measured and reported; and of the evidence for and against its use in diagnosis.

Landmark advances in the development of erythropoietin

This is a Minireview covering landmarks or milestones in the development of erythropoietin (EPO). Thirty-nine landmark advances have been identified, which cover the period 1863-2003. Several reports are included that directly support these original landmark advances. This Minireview also updates some of the advances in EPO research since my last Minireview update on EPO published in this journal in 2003. The areas of EPO research updated are: sites of production; purification, assay and standardization; regulation; action; use in anemias; extraerythropoietic actions; adverse effects; and blood doping. The new reports on the use of EPO in the therapy of myocardial infarction; stroke and other neurological diseases; diabetic retinopathy and other retinal diseases are also covered.

Nutritional Intake in Adult Hemodialysis Patients

BACKGROUND

Research pertaining to the nutritional intake of hemodialysis patients is limited.

PURPOSE

Describe the nutritional quality of foods consumed by hemodialysis patients and variation by day of the week.

METHODS

Dietary recalls were obtained from 22 hemodialysis patients and analyzed using the Nutrition Data System for Research.

RESULTS

Few statistically significant differences were found by day of the week, but several dietary deficits were noted.

CONCLUSION

The data suggest poor intake of calories, protein, and several vitamins and minerals, as well as excess sodium consumption, but little variation by day of the week. Additional research is needed.

Renoprotective effects of asialoerythropoietin in diabetic mice against ischaemia-reperfusion-induced acute kidney injury

AIM

Diabetic patients are at higher risk of failure to recover after acute kidney injury, however, the mechanism and therapeutic strategies remain unclear. Erythropoietin is cytoprotective in a variety of non-haematopoietic cells. The aim of the present study was to clarify the mechanism of diabetes-related acceleration of renal damage after ischaemia-reperfusion injury and to examine the therapeutic potential of asialoerythropoietin, a non-haematopoietic erythropoietin derivative, against ischaemia-reperfusion-induced acute kidney injury in diabetic mice.

METHODS

C57BL/6J mice with and without streptozotocin-induced diabetes were subjected to 30 min unilateral renal ischaemia-reperfusion injury at 1 week after induction of diabetes. They were divided into four group: (i) non-diabetic plus ischaemia-reperfusion injury; (ii) non-diabetic plus ischaemia-reperfusion injury plus asialoerythropoietin (3000 IU/kg bodyweight); (iii) diabetic plus ischaemia-reperfusion injury; and (iv) diabetic plus ischemia-reperfusion injury plus asialoerythropoietin. Experiments were conducted at the indicated time periods after ischaemia-reperfusion injury.

RESULTS

Ischaemia-reperfusion injury of diabetic kidney resulted in significantly low protein expression levels of bcl-2, an anti-apoptotic molecule, and bone morphogenetic protein-7 (BMP-7), an anti-fibrotic and pro-regenerative factor, compared with non-diabetic kidneys. Diabetic kidney subsequently showed severe damage including increased tubular cell apoptosis, tubulointerstitial fibrosis and decreased tubular proliferation, compared with non-diabetic kidney. Treatment with asialoerythropoietin induced bcl-2 and BMP-7 expression in diabetic kidney and decreased tubular cell apoptosis, tubulointerstitial fibrosis and accelerated tubular proliferation.

CONCLUSION

Reduced induction bcl-2 and BMP-7 may play a role in the acceleration of renal damage after ischaemia-reperfusion injury in diabetic kidney. The renoprotective effects of asialoerythropoietin on acute kidney injury may be mediated through the induction of bcl-2 and BMP-7.

Asialoerythropoietin prevents contrast-induced nephropathy

Strategies to prevent contrast-induced nephropathy (CIN) are suboptimal. Erythropoietin was recently found to be cytoprotective in a variety of nonhematopoietic cells, so it was hypothesized that the nonhematopoietic erythropoietin derivative asialoerythropoietin would prevent CIN. Nephropathy was induced in rats by injection of the radiocontrast medium Ioversol in addition to inhibition of prostaglandin and nitric oxide synthesis. Administration of a single dose of asialoerythropoietin before the induction of nephropathy significantly attenuated the resulting renal dysfunction and histologic renal tubular injury. Contrast-induced apoptosis of renal tubular cells was inhibited by asialoerythropoietin both in vivo and in vitro, and this effect was blocked by a Janus kinase 2 (JAK2) inhibitor in vitro. Furthermore, phospho-JAK2/signal transducer and activator of transcription 5 (STAT5) and heat-shock protein 70 increased after injection of asialoerythropoietin, suggesting that the effects of asialoerythropoietin may be mediated by the activation of the JAK2/STAT5 pathway. Overall, these findings suggest that asialoerythropoietin may have potential as a new therapeutic approach to prevent CIN given its ability to preserve renal function and directly protect renal tissue.

Cost analytic model to determine the least costly inpatient erythropoiesis stimulating therapy regimen

BACKGROUND

Unlike in outpatient settings, the comparative costs of epoetin alpha (EPO) and darbepoetin alpha (DARB) have not been evaluated broadly from the inpatient hospital perspective.

OBJECTIVE

To develop a cost analytic model comparing hospital inpatient costs for erythropoiesis stimulating therapies within the nephrology and oncology settings.

METHODS

A cost analytic model incorporating erythropoietic drug, pharmacy, and nursing costs was developed from the inpatient hospital perspective to evaluate comparative costs of EPO and DARB. Erythropoietic drug costs were calculated using unit wholesale acquisition cost multiplied by the number of units or micrograms while comparing the following dosing regimens: EPO 3 times weekly, EPO once weekly, and DARB once weekly. Pharmacy costs included dispensing and delivery costs, while nursing costs incorporated administration time costs; all were calculated by estimated fractional hours per activity multiplied by hourly wages. The total frequency of erythropoiesis stimulating therapy administrations was determined based on the average hospital length of stay. The first erythropoiesis stimulating therapy dose was assumed to occur on day 3 of hospitalization. For total inpatient costs, a weighted average was calculated across disease states. One-way sensitivity analyses were conducted by varying length of stay, day of initial erythropoiesis stimulating therapy dose, pharmacy and nursing costs, and once-weekly DARB dose.

RESULTS

EPO 3 times weekly was the least costly regimen across all disease states evaluated. Threshold analysis indicated that the cost of once-weekly DARB regimens would have to be reduced by 37% to equal the cost of EPO 3 times weekly for an average length of stay. Sensitivity analyses did not considerably affect the results.

CONCLUSIONS

EPO 3 times weekly was found to be the least costly erythropoiesis stimulating therapy regimen for nephrology and oncology inpatients for the average length of stay as well as most other lengths of stay considered. Once-weekly EPO was the least costly erythropoiesis stimulating therapy regimen for several other lengths of stay, while once-weekly DARB was never found to be the least costly regimen.

Haemoglobin and haematocrit targets for the anaemia of chronic kidney disease

BACKGROUND

Anaemia affects 60% to 80% of patients with chronic kidney disease (CKD) reduces quality of life and is a risk factor for early death. Treatment options are blood transfusion, erythropoietin (EPO) and darbepoetin alfa. Recently higher haemoglobin (Hb) and haematocrit (HCT) targets have been widely advocated because of positive associations with improved survival and quality of life from observational studies.

OBJECTIVES

To assess the benefits and harms of different Hb or HCT targets in CKD patients receiving any treatment for anaemia.

SEARCH STRATEGY

We searched The Cochrane Renal Group's specialised register, Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library) MEDLINE (from 1966), EMBASE (from 1980) and reference lists of retrieved articles. Date of most recent search: April 2006

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing different Hb/HCT targets in patients with the anaemia of CKD.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and results expressed as relative risks (RR) for dichotomous outcomes and weighted mean difference (MD) for continuous outcomes, with 95% confidence intervals (CI).

MAIN RESULTS

Twenty two trials (3707 patients) were included. Hb > or = 133 g/L was not associated with a reduction in the risk of all-cause mortality compared with 120 g/L in dialysis and pre-dialysis patients. In pre-dialysis patients, there was a significantly lower end of treatment creatinine clearance with Hb < 120 g/L compared to > 130 g/L (MD -4.17, 95% CI -6.33 to -2.02) but no significant difference in the risk of end-stage kidney disease (ESKD) (RR 1.05, 95% CI 0.50 to 2.22). Lower Hb targets resulted in an increased risk for seizures (RR 5.25, 95% CI 1.13 to 24.34) and a reduced risk of hypertensive episodes (RR 0.50, 95% CI 0.33 to 0.76). There were no significant differences in the risk of vascular access thrombosis.

AUTHORS' CONCLUSIONS

There was no significant difference in the risk of death for low (< 120 g/L) versus higher Hb targets (>133 g/L). Lower Hb targets were significantly associated with an increased risk for seizures but a reduced risk of hypertension. In general study quality was poor. There is a need for more adequately powered, well-designed and reported trials. Trials should be pragmatic, focusing on hard end-points (mortality, ESKD, major side effects) or outcomes which were previously not studied adequately (e.g. seizures, quality of life).

Haemoglobin and haematocrit targets for the anaemia of chronic renal disease

BACKGROUND

Anaemia affects 60-80% of patients with renal impairment, reduces quality of life and is a risk factor for early death. Treatment options are blood transfusion, erythropoietin (EPO) alpha or beta and darbepoetin alfa. Recently higher haemoglobin (Hb) and haematocrit targets have been widely advocated because of positive data from observational studies. However, higher targets may lead to access thrombosis and hypertension and are costly.

OBJECTIVES

This review assesses the benefits and harms of low (Hb </= 100 g/L or HCT </= 30%) and high (Hb > 100 g/L or HCT > 30%) targets in pre- and post-dialysis patients receiving any treatment for anaemia.

SEARCH STRATEGY

We searched The Cochrane Renal Group specialised register (September 2002), Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002) MEDLINE (1966 - September 2002), EMBASE (1988 - September 2002) and reference lists of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing low Hb/HCT targets (Hb</- 100 g/L) with high Hb/HCT targets (Hb > 100 g/dL) in patients with anaemia of chronic renal disease.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes, with 95% confidence intervals (95% CI).

MAIN RESULTS

Fifteen trials were identified in which 2096 patients were included. Twelve trials (673 patients) compared placebo with EPO and three trials (1423 patients) compared two doses of EPO. Hb values of 100 g/L (obtained with low EPO doses) were associated with lower mortality compared to Hb values of 140 g/L or more (obtained with high EPO doses) in the population with chronic renal disease and cardiovascular impairment (two trials, 1379 patients: RR 0.82; 95% CI 0.68 to 0.99). Lower targets obtained with a placebo resulted in an increased risk for seizures (four trials, 219 patients: RR 5.25; 95% CI 1.13 to 24.34) as compared to higher targets reached with EPO treatment. Finally, there was a reduced risk for hypertensive episodes with lower Hb targets reached with a placebo as compared to higher targets reached with EPO (six trials, 387 patients: RR 0.50; 95% CI 0.33 to 0.76). Quality of life was not adequately evaluated in the studies.

REVIEWER'S CONCLUSIONS

Lower Hb targets of 100 g/L were associated with a lower risk of death in the population with cardiovascular impairment and chronic renal disease as compared to Hb 140 g/L. Lower Hb targets (Hb < 100 g/L) were also significantly associated with an increased risk for seizures and a reduced risk of hypertension compared to Hb > 100 g/L. There is a need of more adequately powered, well-designed and reported trials in this area. In particular, randomised controlled trials comparing the benefits and harms of low (Hb < 100 g/L) versus intermediate (Hb 130 g/L) and high (Hb 140 g/L) targets in the pre-dialysis population with chronic renal disease are necessary. In fact, there is a large deficiency of trials in the pre-dialysis population. The new trials should focus on hard outcomes and also look at outcomes which were previously not studied adequately, such as seizures and quality of life, which is to be assessed with validated measures.

Central nervous system disorders after renal transplantation in cats

OBJECTIVE

This study describes the incidence and severity of postoperative central nervous system (pCNS) disorders in feline renal transplant recipients.

STUDY DESIGN

A retrospective study based on the medical records of cats that received renal allografts from 1987 to 1996.

ANIMALS OR SAMPLE POPULATION

Fifty-seven client-owned cats received renal allografts for the treatment of renal failure.

METHODS

The frequency, duration, severity, and treatment of episodes of pCNS disorders were recorded from the medical records.

RESULTS

Twelve (21%) of 57 cats had pCNS disorders 1 hour to 5 days after the surgical procedure. Seven cats survived; four had single or multiple seizure episodes, and two had seizure episodes or disorientation followed by a period of coma. One cat became temporarily ataxic and blind after restraint for venipuncture. Five cats died; all had episodes of disorientation or seizures, or both, that progressed to a nonrecoverable comatose state, respiratory arrest or cardiac arrest, or both. There were no significant differences between the two groups in preoperative serum creatinine, blood urea nitrogen, or cholesterol levels, and intraoperative blood pressure measurements. There were no significant differences in the postoperative serum glucose levels, electrolytes levels, or osmolality between the two groups. The cats with pCNS disorders had a mean preoperative trough cyclosporine A (CyA) whole blood level of 429 ng/mL; cats without pCNS disorders had a significantly (P = .0116) higher mean preoperative trough CyA whole blood level of 736 ng/mL.

CONCLUSION

Central nervous system disorders are a common and often fatal complication of renal transplantation in cats.

CLINICAL RELEVANCE

Recognition of pCNS disorders, and possible causes, will help develop hypotheses to investigate the problem.

Evaluation of surgical scrub methods for large animal surgeons

OBJECTIVE

The objective of this study was to determine the effectiveness of a 5-minute surgical scrub using either a one-brush or a two-brush technique in clean and dirty surgical procedures, and to compare the efficacy of povidone iodine with chlorhexidine as surgical scrub solutions.

STUDY DESIGN

Prospective clinical trial.

METHODS

Nine veterinarians scrubbed their hands on eight separate occasions using either povidone iodine or chlorhexidine gluconate. A 5-minute scrub and either a one-brush or two-brush technique used in both clean and dirty operations were evaluated by taking glove juice samples before scrubbing, immediately after scrubbing, and 30, 60, 90, and 120 minutes after scrubbing. Glove juice samples were cultured and the colonies were counted. Percent reductions of bacterial forming units were calculated for all eight scrub procedures.

RESULTS

All scrub procedures provided an adequate percent reduction in colony forming units (CFU) during the 2-hour sampling period. The number of CFU immediately after scrubbing were significantly lower than prescrub. At 120 minutes, there were significantly fewer CFUs than presecrub, but there were more than immediately after scrubbing. No significant difference in reduction in CFUs were detected between one-brush and two-brush techniques. Both chlorhexidine and povidone iodine scrub solutions adequately reduced bacterial colony counts for 120 minutes after scrubbing regardless of the amount of contamination before skin preparation.

CONCLUSIONS

Bacterial counts after a hand scrub procedure using a one-brush technique were not significantly different than after a procedure that used a two-brush technique. Povidone iodine and chlorhexidine are equally effectively in decreasing bacterial numbers on the skin, given a variety of contamination levels present before the scrub procedure.

CLINICAL RELEVANCE

Surgeons may use either chlorhexidine or povidone iodine for antiseptic preparation of their hands before surgery. A two-brush technique is not necessary.

Iron metabolism: a comprehensive review

Despite its abundance in the earth's crust, iron deficiency is a serious health issue in many parts of the world. Although fundamental observations about iron metabolism and the significance of iron nutriture were first noted some time ago, the molecular mechanisms involved in iron metabolism are just now being defined.

Subtherapeutic erythropoietin and insulin-like growth factor-1 correct the anemia of chronic renal failure in the mouse

Chronic renal failure (CRF) is associated with a hyporegenerative anemia, which is caused primarily by inadequate production of erythropoietin (EPO) by the diseased kidneys and is responsive to exogenous EPO administration. Little is known about compensatory mechanisms that might supervene in anemia with low levels of EPO. Multiple investigations in vitro suggest an important role for insulin-like growth factor-1 (IGF-1) as well as EPO in erythropoiesis. Recently, both EPO and IGF-1 in vitro have been found to stimulate erythroid colony forming units in the mouse. However, no studies have examined the effect of IGF-1, singly and in combination with EPO, in CRF in vivo. This study examined mice with surgically-induced renal failure of six weeks duration that were treated for three weeks with the combination of subtherapeutic doses of both EPO and IGF-1. The single administration of each cytokine caused no significant change in hemoglobin in all CRF mice. In marked contrast the combined administration of the two cytokines produced a striking rise in hemoglobin, resulting in anemia correction in the majority of animals. The response to the combination therapy was comparable to the maximal response obtained with a single EPO dose (10 U) in a dose-finding study. Although the data are limited to utilizing one dose of each cytokine and one preparation of IGF-1, the large increase in hemoglobin observed with the combination therapy indicates that these two cytokines work in concert to stimulate erythroid precursors in CRF. In addition, untreated CRF mice showed markedly increased serum levels of low molecular weight binding proteins for IGF-1, potentially reducing the bioavailability of IGF-1. These findings taken together suggest that the anemia of CRF may represent both an EPO and a functional IGF-1 deficient state.

Serotonin is involved in the pathogenesis of hypertension developing during erythropoietin treatment in uremic rats

The aim of this study was to investigate the mechanism of erythropoietin-induced hypertension in respect to its action on blood serotonergic system. The experiment was carried out on healthy rats and animals with experimental chronic renal failure. Erythropoietin (rHuEPO) injected into the healthy and uremic rats caused an increase in systolic blood pressure. This effect was completely abolished by ketanserin, an antagonist of 5-HT2 receptors. Concomitantly a rise in blood and platelet serotonin concentration was observed. It is concluded that serotonin may play a role in the development of hypertension caused by rHuEPO. Moreover, ketanserin may serve as a drug for pharmacological protection of rHuEPO-induced rise of blood pressure in uremia.

Heme oxygenase induction. A possible factor in aluminum-associated anemia

The effect of repeated parenteral administration of aluminum (Al) was investigated to determine if a relationship exists between the severity of anemia and increase in hepatic heme oxygenase activity. Female Swiss Webster mice were dosed for 11 d with 50 mg Al/kg, as Al lactate, and sodium lactate was given to control mice. On d 12, hematocrit, hemoglobin, blood smears, hepatic heme oxygenase activity, and cytochrome P450 levels were assessed. Significant decreases in hematocrit (39.1 +/- 0.7 vs 43.1 +/- 0.3% in controls) and hemoglobin (13.1 +/- 0.4 vs 14.2 +/- 0.2 g/dL in controls) were produced by Al administration. Blood smears from Al-treated mice consistently showed smaller, more irregular red cells. Cytochrome P450 content was significantly decreased (0.443 +/- 0.043 vs 0.665 +/- 0.055 nmol/mg) whereas hepatic heme oxygenase activity was significantly increased (2.75 +/- 0.34 vs 1.66 +/- 0.20 nmol/mg/h) in Al-treated animals. The production of mild anemia by parenteral aluminum correlated significantly with the increase in heme oxygenase activity, which, although only 66% greater than in control, preceded a significant loss of cytochrome P450. The increased heme oxygenase activity, with subsequent increased destruction of heme and/or heme proteins is discussed as a possible mechanism for the microcytic, hypochromic anemia associated with Al overload.

Iron management during treatment with recombinant human erythropoietin in chronic renal failure

The anemia of chronic renal failure often contributes to the poor functional status in patients with renal insufficiency and results primarily from decreased erythropoietin production. Recombinant human erythropoietin (rHuEpo) results in clinical and symptomatic improvements in patients with anemia of chronic renal failure. Treatment with rHuEpo also improves the quality of life in these patients. Resistance to rHuEpo therapy is not uncommon, however, and often is related to iron deficiency resulting from rapid erythropoiesis during rHuEpo therapy. Interestingly, rHuEpo-treated patients may continue to develop iron deficiency while receiving oral iron. Alternatively, parenteral iron is effective in replenishing iron stores and sustaining erythropoiesis in patients treated with rHuEpo.