Intraperitoneal erythropoietin in children on peritoneal dialysis: A study of pharmacokinetics and efficacy

Use of erythropoiesis-stimulating agents in children with chronic kidney disease: a systematic review

Background

Erythropoiesis-stimulating agents (ESAs) revolutionized the management of anaemia in chronic kidney disease (CKD) when introduced in the late 1980s. A range of ESA types, preparations and administration modalities now exist, with newer agents requiring less frequent administration. Although systematic reviews and meta-analyses have been published in adults, no systematic review has been conducted investigating ESAs in children.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for the conduct of systematic reviews was used. All available literature on outcomes relating to ESAs in children with CKD was sought. A search of the MEDLINE, CINAHL and Embase databases was conducted by two independent reviewers. Inclusion criteria were published trials in English, children with chronic and end-stage kidney disease and use of any ESA studied against any outcome measure. An assessment of risk of bias was carried out in all included randomized trials using the criteria from the Cochrane Handbook for Systematic Reviews of Interventions. Two tables were used for data extraction for randomized and observational studies. Study type, participants, inclusion criteria, case characteristics, follow-up duration, ESA type and dosage, interventions and outcomes were extracted by one author.

Results

Of 965 identified articles, 58 were included covering 54 cohorts. Six were randomized trials and 48 were observational studies. A total of 38 studies assessed the efficacy of recombinant human erythropoietin (rHuEPO), 11 of darbepoetin alpha (DA) and 3 of continuous erythropoietin receptor activator (CERA), with 6 studies appraising secondary outcome measures exclusively. Recruitment to studies was a consistent challenge. The most common adverse effect was hypertension, although confounding effects often limited direct correlation. Two large cohort studies demonstrated a greater hazard of death independently associated with high ESA dose. Secondary outcome measures included quality of life measures, growth and nutrition, exercise capacity, injection site pain, cardiovascular function, intelligent quotient, evoked potentials and platelet function.

Conclusions

All ESA preparations and modes of administration were efficacious, with evidence of harm at higher doses. Evidence supports individualizing treatments, with strong consideration given to alternate treatments in patients who appear resistant to ESA therapy. Further research should focus on randomized trials comparing the efficacy of different preparations, treatment options in apparently ESA-resistant cohorts and clarification of meaningful secondary outcomes to consolidate patient-relevant indices.

Mechanism of cardioprotective effect of erythropoietin-induced preconditioning in rat heart

Objective:

The cardioprotective potential of human recombinant erythropoietin (alpha) (Epo) against ischemia-reperfusion-induced injury is well known. But, the underlying mechanisms are not well elucidated. The aim of this study was to characterize the mechanism involved in the cardioprotective effect of Epo-induced preconditioning in isolated rat heart.

Materials and Methods:

The heart was mounted on a Langendorff apparatus. After 10 min of stabilization, four cycles of ischemic preconditioning (IPC) were given followed by 30 min of global ischemia and 120 min of reperfusion. Epo preconditioning was induced by four cycles of 5-min perfusion of K-H solution containing Epo (1.0 U/ml) followed by 5 min perfusion with K-H solution. Myocardial infarct size was estimated macroscopically using the triphenyltetrazolium chloride staining technique. The extent of myocardial injury was measured by release of lactate dehydrogenase and creatine kinase-MB in the coronary effluent.

Results:

The present study demonstrates that Epo preconditioning was almost as effective as IPC. Administration of Wortmannin (100 nM), a PI-3K inhibitor, or Chelerythrine (1 µM), a protein kinase-C (PKC) inhibitor, or AG490 (5 µM), a JAK-2 inhibitor, significantly attenuated the cardioprotective effects of Epo-induced preconditioning.

Conclusion:

Our result suggest that the cardioprotective potential of Epo-induced preconditioning in isolated rat heart was due to an interplay of the JAK-2, PI-3K and PKC pathways. Inhibition of any one of the three pathways was sufficient to block the cardioprotective effect of Epo-induced preconditioning in isolated rat heart.

Erythropoietin mimics ischemic preconditioning

Ischemic preconditioning is a powerful endogenous phenomenon in which brief periods of a sub-toxic ischemic insult induce robust protection against future, lengthy, lethal ischemia. The cardioprotective effects of ischemic preconditioning are manifest in all species studied so far, including humans. The ability to reproduce the cardioprotective effects of ischemic preconditioning with pharmacological agents raises the possibility that a drug may ultimately be introduced into clinical practice to treat human hearts undergoing ischemia/reperfusion. This chapter focuses on erythropoietin (Epo), a drug that has already been approved for humans and is in current use for the treatment of anemia associated with chronic renal failure, HIV infection, cancer patients on chemotherapy, and to reduce allogenic blood transfusion in surgery patients. Several recent studies have suggested that this cytokine possesses properties far beyond its capacity to produce red blood cells such as the ability to protect tissues including brain, kidney and heart against injury caused by ischemia/reperfusion. Cardioprotection conferred by Epo has been shown to be equal in magnitude to that conferred by ischemic preconditioning. However, the underlying mechanisms by which Epo protects the heart against injury caused by ischemia remain unknown.