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MINIREVIEW

Erythropoietin: Physiology and Pharmacology Update^1,2

Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112–2699

	Abstract

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
This minireview is an update of a 1997 review on erythropoietin (EPO) in this journal (1). EPO is a 30,400-dalton glycoprotein that regulates red cell production. In the human, EPO is produced by peritubular cells in the kidneys of the adult and in hepatocytes in the fetus. Small amounts of extra-renal EPO are produced by the liver in adult human subjects. EPO binds to an erythroid progenitor cell surface receptor that includes a p66 chain, and, when activated, the p66 protein becomes dimerized. EPO receptor activation induces a JAK2 tyrosine kinase, which leads to tyrosine phosphorylation of the EPO receptor and several proteins. EPO receptor binding leads to intracellular activation of the Ras/mitogen-activated kinase pathway, which is involved with cell proliferation, phosphatidylinositol 3-kinase, and STATS 1, 3, 5A, and 5B transcriptional factors. EPO acts primarily to rescue erythroid cells from apoptosis (programmed cell death) to increase their survival. EPO acts synergistically with several growth factors (SCF, GM-CSF, 1L-3, and IGF-1) to cause maturation and proliferation of erythroid progenitor cells (primarily colony-forming unit-E). Oxygen-dependent regulation of EPO gene expression is postulated to be controlled by a hypoxia-inducible transcription factor (HIF-1). Hypoxia-inducible EPO production is controlled by a 50-bp hypoxia-inducible enhancer that is approximately 120 bp 3' to the polyadenylation site. Hypoxia signal transduction pathways involve kinases A and C, phospholipase A₂, and transcription factors ATF-1 and CREB-1. A model has been proposed for adenosine activation of EPO production that involves protein kinases A and C and the phospholipase A₂ pathway. Other effects of EPO include a hematocrit-independent, vasoconstriction-dependent hypertension, increased endothelin production, upregulation of tissue renin, change in vascular tissue prostaglandins production, stimulation of angiogenesis, and stimulation of endothelial and vascular smooth muscle cell proliferation. Recombinant human EPO (rHuEPO) is currently being used to treat patients with anemias associated with chronic renal failure, AIDS patients with anemia due to treatment with zidovudine, nonmyeloid malignancies in patients treated with chemotherapeutic agents, perioperative surgical patients, and autologous blood donation. A novel erythropoiesis-stimulating factor (NESP, darbepoetin) has been synthesized and when compared with rHuEPO, NESP has a higher carbohydrate content (52% vs 40%), a longer plasma half-life, the amino acid sequence differs from that of native human EPO at five positions, and has been reported to maintain hemoglobin levels just as effectively in patients with chronic renal failure as rHuEPO at less frequent dosing. The use of rHuEPO and darbepoetin to enhance athletic performance is officially banned by most sports-governing bodies because the excessive erythrocytosis can lead to increased thrombogenicity and can cause deep vein, coronary, and cerebral thromboses.

Key Words: erythropoietin • darbepoetin • hypoxia • erythropoiesis • receptor • oxygen • hypoxia-inducible factor • adenosine • anemia • doping

	History of Erythropoietin (EPO)

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
It has been almost a century since Carnot and Deflandre (2) postulated that a humoral factor, which they called "hemopoietine," regulates red blood cell production. Their intriguing experiments were carried out in rabbits, where they removed plasma from a donor rabbit after a bleeding stimulus and found that when this plasma was injected into a normal recipient rabbit, a prompt reticulocytosis occurred. Several investigators confirmed the Carnot and DeFlandre experiments (3, 4). However, Erling Hjort (5) reported the most convincing confirmation of Carnot and DeFlande’s work up to that time, which was published in a Norwegian journal in 1936. Hjort reported that erythropoietically active plasma from bled rabbits produced a reticulocytosis when injected into normal recipients in 18 experiments. Krumdieck (6) published very similar findings as Carnot and Hjort in Proceedings of the Society for Experimental Biology and Medicine in 1943 in which they found erythropoietic activity in plasma from bled rabbits when injected into recipient rabbits. Allan Erslev, a pioneer in EPO research, must be given much credit for publishing his work in the journal Blood in 1953 (7) where he injected large volumes of plasma (50 ml per day for 4 days) from donor rats after a bleeding stimulus into normal recipient rats and produced a marked reticulocytosis. One of the most important papers in EPO research is the work of Kurt Reissmann (8), who in 1950, reported in the journal Blood his work in parabiotic rats, when one partner breathed an atmosphere of low oxygen tension and the other partner breathed normal air, both partners developed a reticulocytosis, increase in hemoglobin (Hb), and bone marrow hyperplasia. These findings reawakened interest in EPO. Proof that the kidney is the primary site of EPO production (9–12), that peritubular interstitial cells in the kidney are the renal cells that produce EPO (13, 14), and that the liver is a secondary site of EPO production (15, 16) are major advances in EPO research. One of the most important advances in this field occurred when Miyake et al. (17) reported purification to homogeneity of human EPO. This made it possible for Lin et al. (18) and Jacobs et al. (19) to clone the gene for EPO and to develop a transfected cell line in Chinese hamster ovary cells that provided recombinant EPO for use in clinical anemias. A new molecule has recently been synthesized called "novel erythropoiesis stimulating protein (NESP)," which contains a higher content of carbohydrate and provides a new antianemia agent with a longer circulating plasma half-life in vivo than native EPO (20, 21).

	Sites of Production of EPO

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
It is of historical interest to review the work published on sites of production of EPO. Since the kidney was proven to be the primary site of production of EPO (9–12), a vigorous search for the cells in the kidney that produce EPO has been undertaken. With the cloning of the gene for EPO (18, 19), cDNA probes became available for in situ hybridization studies on the kidney and other organs to determine the cell that produces EPOmRNA. Koury et al. (13) and Lacombe et al. (22) used in situ hybridization studies to demonstrate that the cells containing EPOmRNA were in a peritubular (interstitial or endothelial) location in anemic mouse kidneys. Fisher et al. (14) reported high levels of EPOmRNA in peritubular (interstitial) cells using in situ hybridization studies in hypoxic monkey kidneys. Other investigators have also confirmed a peritubular site for EPO production (23, 24). Maxwell et al. (25), using in situ hybridization and immunohistochemical methods, and Loya et al. (26), using hypoxic transgenic mice, reported a tubular epithelial cell site for EPO production. Other investigators postulated a tubular cell site of EPO production (27–29). Mujais et al. (27) recently reported EPOmRNA in tubular cells using reverse transcriptase-polymerase chain reaction (RT-PCR) in microdissected isolated nephron segments (medullary ascending limb, proximal convoluted tubules, cortical ascending limb, medullary collecting duct, and cortical collecting tubules). It is not clear whether interstitial or endothelial cells were contained in all of these tubular segments. On the other hand, Da Silva et al. (30), using RT-PCR in microdissected nephron segments, could not detect EPOmRNA in any of the above described microdissected nephron segments, but did report significant EPOmRNA in a peritubular location.

	Factors Involved in the Regulation of Erythropoiesis

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
Red cell production (erythropoiesis) is regulated by several cytokines. Figure 1 illustrates the process of erythropoiesis from the primitive pluripotent stem cell to the mature erythrocyte and the points in this maturation process where regulatory factors act to induce commitment and further maturation of the cells involved in the red cell lineage. The growth factors known to be involved in erythropoiesis are granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-6, stem cell factor (SCF), IL-1, IL-3, IL-4, IL-9, IL-11, granulocyte-macrophage (GM)-CSF, insulin growth factor-1 (IGF-1), and EPO. EPO acts on the later stages of development of erythroid progenitor cells. EPO acts primarily on colony-forming unit erythroid (CFU-E) to induce these cells to proliferate and mature through the normoblast into reticulocytes and mature erythrocytes (31, 32). The primary target cell for EPO in the bone marrow is the CFU-E. EPO acts synergistically with SCF, GM-CSF, IL-3, IL-4, IL-9, and IGF-1 to cause maturation and proliferation from the stage of the burst-forming unit erythroid (BFU-E) and CFU-E to the normoblast stage of erythroid cell development (33, 34). Thus, EPO acts primarily on apoptosis to decrease the rate of cell death in erythroid progenitor cells in the bone marrow. SCF, IL-1, IL-3, IL-6, and IL-11 provide the stimulus to cause the differentiation of the pluripotent stem cell into the myeloid stem cell and the CFU-granulocyte, erythroid, monocyte, megakaryocyte (GEMM). The CFU-GEMM gives rise to specific CFU for granulocytes, monocytes, megakaryocytes, macrophages, eosinophils, and erythroid cell precursors (35–37).

View larger version (15K): [in this window] [in a new window]   Figure 1. The growth factors that influence erythropoiesis from the pluripotent stem cell to the mature erythrocyte. See Ref. 194.

	EPO Receptor

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

View larger version (24K): [in this window] [in a new window]   Figure 2. The first step in EPO activation of the receptor is dimerization (1); the pre-associated JAK2 kinases are in close contact and activated by transphosphorylation (2); the tyrosine residues of the EPO receptor are then phosphorylated (3, 4), providing docking sites for intracellular signaling proteins with SH2 domains (5). Lacombe C and Mayeux P. Nephrol Dial Transplant 14(Suppl 2):22–28, 1999. By permission of Oxford University Press.

View larger version (10K): [in this window] [in a new window]   Figure 3. Schematic representation of the intracellular part of the EPO receptor and the identified binding sites for signaling proteins. Lacombe C and Mayeux P. Nephrol. Dial Transplant 14(Suppl 2):22–28, 1999. By permission of Oxford University Press.

	Oxygen-Sensing and Signal Transduction Pathways in Hypoxic Regulation of EPO Gene Expression

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

It has recently been suggested that HIF-1 could be oxidatively modified by ROS and that these short-range interactions require the participation of prolyl hydroxylase enzymes that could be involved in oxygen sensing (79, 80, 100). The HIF-modifying enzyme apparently depends upon both oxygen and iron (101). Models have been proposed by Zhu and Bunn (79) and Semenza (102) for oxygen-dependent regulation of the HIF transcription factor that involves the hydroxylation of a specific proline residue within a highly conserved region of the HIF’s internal oxygen-dependent degradation domain. This structural modification is necessary for HIF binding to Von Hipple-Lindau protein. Ubiquitination of HIF is necessary for this transcription factor to be degraded by the proteasome, and this ubiquitination of HIF requires direct binding to the ß-domain of the Von Hipple-Linadau proteins (103). Two independent regions within the HIF-1 oxygen-dependent degradation domain (ODDD) are targeted for ubiquitination by E₃ ubiquitin ligase in a manner dependent upon prolyl hydroxylation (104): a conserved HIF-VHL-prolyl hydroxylase pathway in C. elegans, and with the use of a genetic approach to identify EGL-9, a dioxygenase that regulates HIF by prolyl hydroxylation has been defined (105); a conserved family of HIF prolyl hydroxylase (HPH) enzymes that appear to be responsible for a ubiquitin-ligase complex that recognizes a hydroxylated proline residue in HIF (posttranslational modification) (106). It has recently been demonstrated that the ARNT partner is recruited to HIF-1 in the nucleus (not before HIF-1 enters the nucleus), and the resulting HIF-1 ARNT heterodimer recognizes HRE’s of target genes (107). The mechanism of activation of HIF-1 is a multistep process that includes hypoxia-dependent nuclear import and activation (derepression) of the transactivation domain, resulting in recruitment of the CREB-binding protein (CBP)/p300 coactivation (107). Thus, CBP has been demonstrated in a hypoxia-dependent manner to stimulate the HIF-1/ARNT-heterodimer on a minimal HRE-containing promoter (107). Semenza (102) has proposed a model for the regulation of HIF-1 expression by cellular oxygen concentration that is shown in Figure 4. The model postulates that when cells are hypoxic, the proline is not hydroxylated and HIF- escapes degradation (102). Further proof is needed to prove that this model plays a role in EPO gene expression in vivo.

View larger version (11K): [in this window] [in a new window]   Figure 4. Regulation of HIF-1 expression by cellular O2 concentration. O2 availability determines the rate at which HIF-1 is subject to prolyl hydroxylation by PHDs 1-3. Prolyl hydroxylation is required for the interaction of HIF-1 with VHL, which recruits elongins B and C, Cullin 2 (CUL2), and RBX1 (R) to constitute a functional E3 ubiquitin-protein ligase complex. Ubiquitination of HIF-1 targets the protein for degradation by the 26S proteasome. Under hypoxic conditions, HIF-1ß dimerizes with HIF-1, which escapes prolyl hydroxylation, ubiquitination, and degradation. The HIF-1 heterodimer binds to hypoxia response elements containing the core recognition sequence 5'-RCGTG-3' and recruits coactivator (Coact) molecules, resulting in increased transcription initiation complex (TIC) formation and mRNA synthesis, which ultimately results in the production of proteins that mediate physiologic responses to hypoxia. The battery of HIF-1 target genes that are expressed in response to hypoxia is cell-type specific and is determined by the binding of other transcription factors (TFs), which establish basal rates of transcription. See Ref. 102. Published with permission from Elsevier Science.

View larger version (21K): [in this window] [in a new window]   Figure 5. Model for adenosine protein kinases A and C, and phospholipase A2 in hypoxic regulation of EPO production. CC, chelerythrine; PLC, phospholipase C; PLA2, phospholipase A2; AC, adenylate cyclase; R, receptor; DAG, diacylglycerol; IP3, inositol trisphosphate; PIP2, phosphatidylinositol 4,5-biphosphate; TP, transcriptional proteins; Gq, G protein that activates phosphoinositide-specific PLC; Gs, G-stimulating proteins; Gp, G protein that activates PLA2; NECA, 5'-(N-ethylcarboxamido) adenosine; MP, mepacrine; FFA, free fatty acids; PC, phosphatidylcholine. Published with permission from Fisher JW and Brookins J (Ref. 115).

	Therapeutic Uses of EPO in Anemia

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

The National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) reported, in 1997 (124), the results of a work group that established evidence based guidelines for the management of the anemia of CRF. In 2000, Eschbach (125) outlined several principles related to anemia management of patients with CRF being treated with rHuEPO:

1. The clinical response of the patient with CRF to rHuEPO does not occur unless doses of >15 U/kg i.v., three times weekly, are administered. Further increase in response is not likely to occur at doses above 500 U/kg i.v. three times weekly (125).
   
2. On the average, subcutaneous (s.c.) administration is more effective than i.v. or i.p. injections even though only 25% of the s.c. administered dose is absorbed (126).
   
3. Pharmacokinetic studies show that rHuEPO has a half-life (T) after i.v. administration of 4–9 hr, whereas the T after s.c. injection is >24 hr (127).
   
4. It is important not to discontinue rHuEPO just because the target Hb has been achieved. The Hb level may fall more abruptly than anticipated if therapy is stopped because the rising Hb suppresses endogenous EPO production (128).
   
5. Treatment with RHuEPO leads to iron deficiency and it is essential that the patient with anemia of CRF being treated with rHuEPO be followed for symptoms of iron deficiency, e.g., serum ferritin, transferrin saturation, etc.
   

Even though the best target Hb level that should be achieved in patients with CRF has been somewhat controversial, the European Best Practice Guidelines has recommended that a target hemoglobin of >11g/dl be achieved for 85% of patients with CRF (129). To attain this target, the population median will be 12.0–12.5g/dl. They recommend that the target Hb may need to be varied for patients with CRF with specific comorbidities (129). A National Kidney Foundation ad hoc committee recommended a target hematocrit of 33%–38% (130). However, the FDA in the U.S. recommended a hematocrit range up to 36%, and this is the basis for reimbursements of patients treated with EPO in the U.S. Other investigators reported that current evidence-based recommendations suggest a target hematocrit range of 33%–36%, but caution that normalization of the hematocrit in hemodialysis patients with symptomatic heart disease has shown an increase in both mortality and the rate of vascular access thrombosis (131). The value of early management of patients with CRF has been stressed (132). The objective of early referral in patients with CRF is apparently to prevent complications as the disease progresses to the stage where dialysis or transplantation becomes necessary (132). When dialysis is initiated after the development of uremia, the poor nutritional status, severe acidosis, and anemia and poorly controlled hypertension makes the patient more difficult to manage. It has been suggested that nephrology referral should be centered around controlling anemia with rHuEPO, high blood pressure with appropriate drugs (especially converting enzyme inhibitors), nutritional status with adapted protein-calorie intake, and renal osteodystrophy with calcium carbonate or recombinant growth hormone in children (132). It has been suggested that chronic renal disease progression may be slower when anemia is reversed, emphasizing the benefits of early correction of the anemia with EPO (133).

The mechanism of the anemia of CRF is probably due to the inability of the kidneys with compromised renal function to produce sufficient amounts of EPO to meet the demands for new red cell production in patients with uremia. Over the years, there has been some controversy over the role of the bone marrow response to endogenous EPO in patients with uremic end-stage renal disease. Obviously, the primary cause of the anemia in CRF is due to the lack of sufficient amounts of EPO to maintain steady-state erythropoiesis due to the reduced red cell life span, deficiency of iron and folic acid, hyperparathyroidism with myelofibrosis, aluminum toxicity, blood loss, and inhibition of erythropoiesis caused by "uremic toxins." However, serum levels of EPO in normal human subjects range between 1 and 27 mu/ml (mean 6.2 ± 4.3 mu/ml, n = 53), (134). On the other hand, serum levels of EPO in patients with CRF were between 4.2 and 102 mu/ml (mean 29.5 ± 4.0 mu/ml, n = 36) (134). Thus, it seems that even though EPO deficiency is the primary cause of the anemia of CRF, the uremic state may blunt the bone marrow response to EPO. Serum levels of EPO in patients with CRF were about five times as high in patients with CRF than in normal human subjects (134). McGonigle et al. (135) and Radtke et al. (136) reported several years ago a suppressed response of bone marrow cultures to EPO in the presence of plasma from patients with anemia. Macdougall (137) has recently summarized the role of "uremic toxins" in exacerbating the anemia in patients with CRF. Candidates suggested to play a role in uremic inhibition of erythropoiesis are polyamines, parathyroid hormone, and some inflammatory cytokines (137). Radtke et al. (136) and Kushner et al. (138) provided some support for polyamines as one of several uremic toxins that could be responsible for the suppressed response of the bone marrow to EPO in the patient with anemic CRF. Allen et al. (139) reported that when bone marrow from patients with uremia with and without inflammatory disease was cultured with autologous serum, the optimal response to EPO was significantly inhibited. Treatment of parallel cultures with a combination of antibodies to interferon- (IFN-) and tumor necrosis factor- (TNF-) almost completely restored the response to EPO. They conclude that CFU-E colony formation is inhibited by soluble factors present in the sera of patients with uremia with or without inflammatory disease (139). Erslev and Besarab (140) compared the rate and control of baseline red cell production in hematologically stable patients and uremic patients with anemia. The erythrokinetic rates in the anemic uremic patients were about one-half the rate in normal hematologically stable individuals even though the serum EPO titers were the same or higher in the anemic uremic patients (140). It is also of interest that patients with CRF undergoing ambulatory peritoneal dialysis maintain significantly higher hematocrits than patients on hemodialysis (141, 142). Thus, it seems possible that pharmacological doses of EPO in patients with CRF may overwhelm the bone marrow and correct both the EPO deficiency and the suppressed bone marrow response to EPO.

The cardiovascular effects of EPO and anemia correction has been summarized by Vaziri (143). It appears that EPO-induced hypertension is not due to the amelioration of anemia because a similar rise in blood pressure occurs in EPO-treated iron-deficient animals and humans even though the anemia persists (144, 145). Chronic administration of EPO results in hematocrit independent, vasoconstriction-dependent hypertension that is largely due to elevated resting and agonist-stimulated cytoplasmic calcium concentrations, which leads to resistance to the vasodilatory action of nitric oxide (144, 146). Other factors that may be involved in the hypertensive action of EPO are increased endothelin production (147, 148), upregulation of tissue renin and angiotensinogen production (149), and changes in vascular tissue prostaglandins (147, 150). EPO has also been demonstrated to promote angiogenesis (151–153) and to stimulate endothelial and vascular smooth muscle cells (154). In addition, correction of anemia in patients with CRF may partly prevent or reverse left ventricular hypertrophy in dialysis-dependent and dialysis-independent patients with chronic renal insufficiency (155). It has also been reported that inborn erythrocytosis leads to cardiac dysfunction and premature death in mice overexpressing EPO (156). Finally, it has been reported that neutralizing anti-EPO antibodies and pure red cell aplasia developed in 13 patients with anemia of CRF during treatment with epoetin (157).

Suppression of erythroid progenitor cells in the bone marrow (158) and anemia (159, 160) are frequently seen as side effects of Zidovudine treatment of patients with AIDS. Patients with AIDS with endogenous serum EPO levels <500 mu/ml who are receiving doses of Zidovudine <4,200 mg per week usually respond to rHuEPO therapy (159). However, patients with serum EPO levels >500 mu/ml usually do not respond to RHuEPO therapy (160).

RHuEPO is being used to treat patients with anemia associated with nonmyeloid malignancies where the anemia is due to the effects of concomitantly administered chemotherapy. RHuEPO was reported to be effective in the treatment of patients with cancer receiving cisplatin (161). A study of 3012 patients with nonmyeloid malignancies who were receiving chemotherapy was carried out in a multicenter, open label, nonrandomized study conducted in 600 United States community-based practices (162). Of the study patients, 819 (27.6%) received taxane chemotherapy, 349 (11.8%) received cisplatin chemotherapy, and 682 (23.0%) received carboplatin chemotherapy. Patients were administered 40,000 units of rHuEPO once weekly by the s.c. route, which could be increased to 60,000 units one time per week after 4 weeks, depending upon the hemoglobin response. Treatment was continued for a maximum of 16 weeks. Patients who were accessible for efficacy evaluation (2,964) were observed to have significant increases in Hb levels, decreases in transfusion requirements, and improvements in functional status and fatigue. In another randomized, double-blind, placebo controlled study of 375 patients with anemia receiving nonplatin chemotherapy with solid or nonmyeloid hematologic malignancies were treated with rHuEPO- at dosages of 150–300 I.U./kg three times per week s.c. for 12–24 weeks. rHuEPO- significantly decreased transfusion requirements and increased Hb (164). An increase in energy level and ability to do daily activities were significantly greater in the rHuEPO- group when compared with the placebo patients (163).

rHuEPO was studied in a double-blind clinical trail in 316 patients prior to elective orthopedic hip or knee surgery (164). The patients were randomly assigned according to pretreatment Hb levels to receive 300 u/kg, 100 u/kg, or placebo s.c. for 10 days before surgery, on the day of surgery, and for 4 days after surgery (165). The dosage of 300 u/kg rHuEPO significantly reduced the risk of allogenic transfusions. In patients with pretreatment Hb of >10 to <13 g/dl, there was not a significant difference in the transfusion requirements between 100 u/kg rHuEPO and the placebo group. In another study of 145 patients scheduled for orthopedic hip or knee surgery who received 600 u/kg rHuEPO s.c. once weekly for 3 weeks prior to surgery and on the day of surgery or 300 u/kg once daily for 10 days prior to surgery, on the day of surgery, and for 4 days after surgery (166), the increase in Hb in the 600 u/kg weekly group was significantly greater than that observed for the 300 u/kg group.

rHuEPO has been investigated for use in myelodysplastic syndrome (166), preoperative autologous blood donation (167, 168), anemia of pregnancy (169), rheumatoid arthritis (170), anemia of prematurity (171, 172), bone marrow transplantation alone (173), and in combination with G-CSF (174). Evidence-based guidelines for anemia management in patients with CRF have been outlined by the National Kidney Foundation Dialysis outcomes Quality Initiative (125), which supplements guidelines for the clinical use of RHuEPO previously reported (130, 175). In a Phase III multicenter clinical trial (176) of rHuEPO in 333 hemodialysis patients with a median maintenance dose of 75 u/kg i.v. three times a week for approximately 13 months, the adverse effects noted were myalgias, 5%; iron deficiency, 43%; increased blood pressure, 35%; and seizures, 5.4% (176). The patients that did not respond had complicating causes for the anemia, such as myelofibrosis, osteitis fibrosa, osteomyelitis, and acute or chronic blood loss (176). If delayed or diminished response to doses of rHuEPO within the recommended dosing range occurs, the following etiologies should be considered:

1. Iron deficiency: all patients will eventually require supplemental iron therapy.
   
2. Underlying infections, inflammatory or malignant processes.
   
3. Occult blood loss.
   
4. Underlying hematologic disease.
   
5. Vitamin deficiencies: folic acid or vitamin B-12.
   
6. Hemolysis.
   
7. Aluminum intoxication.
   
8. Osteitis fibrosa cystica.
   

	Novel Erythropoiesis Stimulating Protein (NESP)

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
It was well known from previous experiments that sialic acid residues on EPO are responsible for maintaining in vivo biological activity of EPO (177). EPO is known to be desialylated in vivo, cleared from plasma, and is bound to galactose receptors in the liver (178). Thus, there is a direct correlation between the amount of sialic acid-containing carbohydrates, plasma half-life, and in vivo biological activity (177, 178). With this knowledge, it was conjectured that increasing the carbohydrate content of EPO would result in a longer plasma half-life and enhanced biological activity. Thus, a new molecule, NESP, was synthesized using the latest techniques of DNA technology (20, 21). An overview of the efficacy and safety of NESP has been reported by Macdougall (179). NESP contains five N-linked oligosaccharide chains, whereas native erythropoietin contains three oligosaccharide chains. The amino acid sequence of NESP differs from that of native human EPO at five positions (Ala30Asn, His32Thr, Pro87Val, Trp88Asn, and Pro90Thr), which allows for attachment of additional oligosaccharides at asparagine residue positions 30 and 88 (20). NESP contains 22 sialic acid residues compared with 14 sialic acid residues for native EPO. The molecular weight of NESP is 38,500 daltons and native EPO is 30,400 daltons; the total carbohydrate for NESP is 52% and native EPO is 40%. NESP binds to the EPO receptor in an identical manner as native EPO to induce intracellular signaling involving tyrosine phosphorylation by JAK-2 kinase and the same intracellular molecules Ras/MAP-k, P13-k, and STAT-5 as native EPO. In comparing the i.v. pharmacokinetics of NESP and rHuEPO in patients on dialysis (178), the mean terminal half life for NESP was three times longer than for rHuEPO (25.3 vs 8.5 hr). The clearance of NESP was significantly less than that of rHuEPO (1.6 ± 0.3 vs 4.0 ± 0.3 ml/hr/kg); the volume of distribution for NESP and rHuEPO were equivalent (52.4 ± 2.0 vs 48.7 ± 2.1 ml/kg). Given s.c., the mean terminal half-life for NESP was 48.8 hr. Apparently, the half-life for SC rHuEPO is 18–24 hr. When given once weekly i.v., NESP reaches a steady state within 4 weeks and does not accumulate.

The s.c. and i.v. pharmacokinetic profiles of NESP in patients on dialysis support the hypothesis that patients with anemia of CRF require less frequent doses of NESP when compared with rHuEPO (180–182). Three safety and efficacy studies of NESP in patients with anemia of CRF have been completed (183–185). The first two multicenter studies were to evaluate the efficacy of NESP in treating the anemia of CRF in patients on dialysis (183, 184). The third study was to evaluate the safety and effectiveness of NESP in maintaining Hb when administered at less frequent dosing compared with rHuEPO (185).The authors concluded from these studies that NESP is effective in the treatment of anemia of CRF and is safe; that the weekly dose for most patients appeared to be 0.45 µg; and that for both i.v. and s.c. dosing, once weekly dosing with NESP was possible. It was concluded that NESP can maintain the Hb concentration just as effectively as rHuEPO at less frequent dosing. The adverse effects, withdrawals, and deaths were the same for the NESP as that reported for rHuEPO treatment (184). There have been no reports thus far of antibody production in patients treated with NESP.

In other studies of previously untreated patients suffering from anemia of CRF, NESP at a dosage of 0.45 µg/kg s.c. once weekly was just as effective in increasing Hb as rHuEPO at 50 units/kg two or three times weekly (184). Darbepoetin- (NESP) has been approved by the U.S. FDA for the treatment of anemia caused by CRF, and may be approved soon for use in cancer patients with anemia associated with chemotherapy (186).

	Blood Doping

Top Abstract History of Erythropoietin (EPO) Sites of Production of... Factors Involved in the... EPO Receptor Oxygen-Sensing and Signal... Therapeutic Uses of EPO... Novel Erythropoiesis Stimulating... Blood Doping References

 
Blood doping may be defined as the artificial increase in Hb/hematocrit to enhance performance. The first report of blood doping was in a controlled experiment in 1947 (187). However, blood doping did not gain attention until following the Mexico City Olympics in 1968 in which athletes won endurance races by competition from high altitude training sites, which was a type of physiological blood doping. Ekblum et al. (188) showed in a landmark paper that blood doping increased VO_2max and running time to exhaustion by 9% and 23%, respectively. Ekblum and Berglund (189) reported a trial that was uncontrolled with rHuEPO in athletes and their results showed that rHuEPO administration improved VO_{2 max} and running times to exhaustion in conjunction with increases in hematocrits. Jelkmann (190, 191) has reviewed the use of recombinant EPO as an antianemic and performance-enhancing drug. This investigator concludes that rHuEPO doping is not only unethical and illegal, but potentially dangerous. Shaskey and Green (192) have pointed out that the improvements in performance of athletes using EPO as a performance-enhancing drug are not without risk, and the use of exogenous EPO has the potential for increased viscosity of the blood and thrombosis with potentially fatal results. It is important to point out that use of rHuEPO to improve athletic performance can be even more dangerous than invasive traditional blood doping through transfusion. Excessive erythrocytosis can lead to increased blood viscosity and thrombogenicity and can cause deep vein thromboses, pulmonary emboli, coronary thromboses, or cerebral thromboses that can be exaggerated by dehydration. The use of rHuEPO to enhance athletic performance is officially banned by most sports-governing bodies and is to be condemned. There is a need to develop better detection methods using traditional urine testing. Abuse of EPO is currently difficult to detect because the routine assay for EPO is an immunoassay that immunologically cannot distinguish recombinant EPO from natural endogenous EPO (193). Darbepoetin- (NESP) has been reported recently to be used as a doping agent and was the cause of the disqualification of two athletes performing in the 2002 Winter Olympics in Salt Lake City. Its use as a doping agent is also to be condemned because the excessive erythrocytosis can lead to increased blood viscosity, thromboembolism, and death.

EPO has been reported to activate specific receptors in the cental nervous system and was found to be neurotrophic and neuroprotective in both in vitro and in vivo models (195, 196). EPO and the EPO receptor have both been reported in the brain cortex, cerebellum, hippocampus, pituitary gland and spinal cord (195). The mechanisms which have been proposed by which EPO produces a neuroprotective effect are (196): reduction in glutamate toxicity, increased production of neuronal anti-apoptotic factors, reduced nitric oxide mediated injury, anti-inflammatory effects, and anti-oxidant properties.

	Footnotes

 
¹ This work was supported by funds from the Tulane Regents Professor in Pharmacology Fund.

² This manuscript is an update of a previously published minireview entitled, "Erythropoietin: Physiologic and Pharmacologic Aspects." PSEBM 216:358–369, 1997.

³ To whom requests for reprints should be addressed at Department of Pharmacology, SL83 Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112–2699. E-mail: jfisher{at}tulane.edu

	References

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1. Fisher JW. Eyrthropoietin: physiologic and pharmacologic aspects. Proc Soc Exp Biol Med 216:358–369, 1997.[Medline]
2. Carnot P, DeFlandre C. Sur l’activite hemopoietique de serum au cours de la regeneration du sang. C R Acad Sci (Paris) 143:384–386, 1906.
3. Gibelli C. Uber den wert des serums anamisch gemachten tiere bei der regeneration des blutes. Arch Exp Pathol Pharmacol 65:284–302, 1911.
4. Sandor G. Uber die blutbidende wirkung des serums von tieren, die in verdunnter luft gehalten wuren. Z Gesante Exp Med 82:633–646, 1932.
5. Hjort E. Reticulocyte increase after injection of anemic serum. Mag F Laegividensk 97:270–277, 1936.
6. Krumdieck N. Erythropoietic substance in the serum of anemic animals. Proc Soc Exp Biol Med 54:14–17, 1943.
7. Erslev AJ. Humoral regulation of red cell production. Blood 8:349–357, 1953.[Abstract/Free Full Text]
8. Reissmann KR. Studies on the mechanism of erythropoietin stimulation in parabiotic rats during hypoxia. Blood 5:347–380, 1950.
9. Jacobson LO, Goldwasser E, Fried W, Plzak L. Role of the kidney in erythropoiesis. Nature 179:633, 1957.[Medline]
10. Fisher JW, Birdwell BJ. Erythropoietin production by the in situ perfused kidney. Acta Haematol 26:224–232, 1961.[Medline]
11. Kuratowska Z, Lewartowski B, Michalski E. Studies on the production of erythropoietin by isolated perfused organs. Blood 18:527–534, 1961.[Abstract/Free Full Text]
12. Erslev AJ. In vitro production of erythropoietin by kidneys perfused with a serum free solution. Blood 44:77–85, 1974.[Abstract/Free Full Text]
13. Koury ST, Bondurant MS, Koury MJ. Localization of erythropoietin synthesizing cells in murine kidneys by in situ hybridization. Blood 71:524–537, 1988.[Abstract/Free Full Text]
14. Fisher JW, Koury S, Ducey T, Mendel S. Erythropoietin (Epo) production by interstitial cells of hypoxic monkey kindeys. Br J Haematol 95:27–32, 1996.[Medline]
15. Zanjani ED, Poster J, Burlington H, Mann LI, Wasserman LR. Liver as the primary site of erythropoietin production in the fetus. J Lab Clin Med 89:640–644, 1977.[Medline]
16. Koury ST, Bondurant MC, Koury MJ, Semenza GL. Localization of cells producing erythropoietin in murine liver by in situ hybridization. Blood 77:2497–2503, 1991.[Abstract/Free Full Text]
17. Miyake T, Kung CKH, Goldwasser E. Purification of human erythropoietin. J Biol Chem 252:5558–5564, 1977.[Abstract/Free Full Text]
18. Lin FK, Suggs S, Lin CH, Browne JK, Smailing R, Egric JC, Chen KK, Fox GM, Martin F, Wasser Z. Cloning and expression of the human erythropoietin gene. Proc Natl Acad Sci U S A 92:7850–7884, 1985.
19. Jacobs K, Shoemaker C, Rudersdorf R, Neill SD, Kaufman RJ, Mufson A, Seehra A, Jones SS, Hewick R, Fritsch EF, Kawakita M, Shimiza T, Miyoke T. Isolation and characterization of genomic cDNA clones of human erythropoietin. Nature 313:806–810, 1985.[Medline]
20. Egrie JC, Browne JK. Development and characterization of novel erythropoiesis stimulating protein (NESP). Br J Cancer 84(Suppl 1):3–10, 2001.
21. MacDougall IC. Novel erythropoiesis stimulating protein. Semin Nephrol 20:375–381, 2000.[Medline]
22. Lacombe C, DaSilva JL, Bruneval P, Fournier JG, Wendling F, Casadevall N, Camilleri JP, Bariety J, Varet B, Tambourin P. Peritubular cells are the site of erythropoietin synthesis in the murine hypoxic kidney. J Clin Invest 81:620–623, 1988.
23. Semenza GL, Koury ST, Nejfelt MK, Gearhart JD, Antonarakis SE. Cell-type-specific and hypoxia-inducible expression of the human erythropoietin gene in transgenic mice. Proc Natl Acad Sci U S A 88: 8725–8729, 1991.[Abstract/Free Full Text]
24. Darby IA, Evans BA, Fu P, Lim GM, Moritz KM, Wintour EM. Erythropoietin gene expression in fetal and adult sheep kidney. Br J Haematol 89:266–270, 1995.[Medline]
25. Maxwell AP, Lappin TR, Johnston J, Bridges CF, McGeown MG. Erythropoietin production in kidney tubular cells. Br J Haematol 74: 535–539, 1990.[Medline]
26. Loya F, Yang Y, Lin H, Goldwasser E, Albitar M. Transgenic mice carrying the erythropoietin gene promoter linked to lacZ express the reporter in proximal convoluted tubule cells after hypoxia. Blood 84: 1831–1836, 1994.[Abstract/Free Full Text]
27. Mujais SK, Bery N, Pullman TN, Goldwasser E. Erythropoietin is produced by tubular cells of the rat kidney. Cell Biochem. Biophysics 30:153–166, 1999.
28. Smith DH, Maples PB, Beru N, Goldwasser E. Identification of erythropoietin producing cells in mammalian kidneys by in situ hybridization. Blood 68:170A, 1986.
29. Rich IN, Noe GI, Vogt CA, L’emke C. Erythropoietin is produced in the tubules of the renal cortex. Blood 76 (Suppl 1): 639A, 1990.
30. Da Silva JL, Schwartzman ML, Goodman A, Levere RD, Abraham NG. Localization of erythropoietin mRNA in the rat kidney by polymerase chain reaction. J Cell Biochem 54:239–246, 1994.[Medline]
31. Gregory CJ, Eaves AC. Human marrow cells capable of erythropoietic differentiation in vitro: definition of three erythroid colony responses. Blood 49:855–864, 1974.[Abstract/Free Full Text]
32. Gregory CJ, Eaves AC. Three stages of erythropoietic progenitor cell differentiation distinguished by a number of physical and biologic properties. Blood 51:527–537, 1978.[Abstract/Free Full Text]
33. Wu H, Liu X, Jaenisch R, Lodish HF. Generation of committed erythroid BFU-E and CFU-E progenitors does not require erythropoietin or the erythropoietin receptor. Cell 83:59–67, 1995.[Medline]
34. Lin CS, Lim SK, D’Agati V, Costantini F. Differential effects of an erythropoietin receptor gene disruption on primitive and definitive erythropoiesis. Genus Dev 10:154–164, 1996.
35. Wu H, Klingmuller U, Besmer P, Lodish HF. Interaction of the erythropoietin and stem-cell-factor receptors. Nature 377:242–246, 1995.[Medline]
36. Jacobs-Helber SM, Penta K, Sun Z, Lawson A, Sawyer ST. Distinct signaling from stem cell factor and erythropoietin in HCD57 cells. J Biol Chem 272:6850–6853, 1997.[Abstract/Free Full Text]
37. Dessypris EN, Gleaton JH, Armstrong OL. Effect of human recombinant erythropoietin on human marrow megakaryocyte colony formation in vitro. Br J Haematol 65:265–269, 1987.[Medline]
38. D’Andrea AD, Zon LI. Erythropoietin receptor: colon subunit structure and activation. J Clin Invest 86:681–687, 1990.
39. Sawada K, Krantz SB, Dai C-H, Koury ST, Horn ST, Glick AD, Civin CI. Purification of human blood burst-forming units-erythroid and demonstration of the evolution of erythropoietin receptor. J Cell Physiol 142:219–230, 1990.[Medline]
40. Wickrema A, Krantz SB, Winkelmann JC, Bondurant MC. Differentiation and erythropoietin receptor gene expression in human erythroid progenitor cells. Blood 80:1940–1949, 1992.[Abstract/Free Full Text]
41. Sawyer ST, Koury MJ. Erythropoietin requirement during terminal erythroid differentiation: the role of surface receptors for erythropoietin (Abs). J Cell Biol 105:1077, 1987.
42. D’Andrea AD, Lodish HF, Wong GG. Expression cloning of the murine erythropoietin receptor. Cell 57:277–285, 1989.[Medline]
43. Livuah O, Stura EA, Middleton SA, Johnson DC, Jokiffe CK, Wilson TA. Crystallographic evidence for performed divers of erythropoietin receptor before ligand activation. Science 283:987–990, 1999.[Abstract/Free Full Text]
44. Remy I, Wilson IA, Michnick SW. Erythropoietin receptor activation by a ligand-induced conformation change. Science 283:990–993, 1999.[Abstract/Free Full Text]
45. Philo JS, Aoki KH, Arkaws T, Nahri LO, Wen J. Dimerization of the extracellular domain of the erythropoietin (Epo) receptor by Epo: one high-affinity and one low-affinity interaction. Biochemistry 35:1681–1691, 1996.[Medline]
46. Kubatzky KK, Ruan W, Gurezka R, Cohen J, Kettelr R, Watowich, Neumann D, Langosch D, Klingmuller U. Self assembly of the transmembrane domain promotes signal transduction through the erythropoietin receptor. Curr Biol 11:110–115, 2001.[Medline]
47. Constantinescu JN, Keren T, Socolovsky M, Nam H, Henis YI, Lodish HF. Ligand-independent oligomerizatin of cell-surface erythropoietin receptor is mediated by the transmembrane domain. Proc Natl Acad Sci U S A 98:4379–4384, 2001.[Abstract/Free Full Text]
48. Mayeux P, Lacombe C, Casadevall N, Chretien S, Dusanter I, Gisselbrecht S. Structure of the murine erythropoietin receptor complex. Characterization of the erythropoietin cross-linked proteins. J Biol Chem 266:23380–23385, 1991.[Abstract/Free Full Text]
49. Qiu H, Belanger A, Yoon HW, Bunn HF. Homodimerization restores biological activity to an inactive erythropoietin mutant. J Biol Chem 273:11173–11176, 1998.[Abstract/Free Full Text]
50. Witthuhn B, Quelle FW, Silvennoinen O, Yi T, Tang B, Miura O, Ihle JN. JAK2 associates with the erythropoietin receptor and is tyrosine phosphorylated and activated following Epo stimulation. Cell 74:227–236, 1996.
51. Hilton CJ, Berridge MV. Conserved region of the cytoplasmic domain is not essential for erythropoietin-dependent growth. Growth Factors 121:263–276, 1995.
52. Miura O, D’Andrea A, Kabat D, Ihle JN. Induction of tyrosine phosphorylation by the erythropoietin receptor correlates with mitogenesis. Mol Cell Biol 11:4895–4902, 1991.[Abstract/Free Full Text]
53. Yoshimura A, Lodish HF. In vitro phosphorylation of the erythropoietin receptor and an associated protein, pp130. Mol Cell Biol 12: 706–715, 1992.[Abstract/Free Full Text]
54. Constantinescu SN, Huang LJ, Nam H, Lodish HF. The erythropoietin receptor cytosolic juxtamembrane domain contains an essential, precisely oriented, hydrophobic motif. Mol Cell 7:377–385, 2001.[Medline]
55. Zang H, Sato K, Nakajuma H, McKay C, Ney PA, Ihle JN. The distal region and receptor tyrosines of the EPO receptor are non-essential for in vivo erythropoiesis. EMBO J 20:3156–3166, 2001.[Medline]
56. Von Lindern M, Parren-Von Amehvort M, Von Dijk T, Deiner E, Von Den Akker E, Von Erst-de Vries S, Williams P, Beng H, Lowenberg B. Protein kinase c- controls erythropoietin receptor signaling. J Biol Chem 275:34719–34727, 2000.[Abstract/Free Full Text]
57. Koury MJ, Sawyer ST, Brandt SJ. New insights into erythropoiesis. Curr Opin Hematol 9:93–100, 2002.[Medline]
58. Carrol MP, Spivak JL, McMahon M, Weich N, Rapp UR, May WS. Erythropoietin induces Raf-1 activation and Raf-1 is required for erythropoietin-mediated proliferation. J Biol Chem 266:14964–14969, 1991.[Abstract/Free Full Text]
59. Gobert S, Duprez V, Lacombe C, Gisselbrecht S, Mayeux P. Erythropoietin activates three forms of MAP kinase in UT7 erythroleukemia cells. Eur J Biochem 234:75–83, 1995.[Medline]
60. Miura Y, Muira O, Ihle JN, Aoki N. Activation of the mitogen activated protein kinase pathway by the erythropoietin receptor. J Biol Chem 269:29962–29969, 1994.[Abstract/Free Full Text]
61. Damen JE, Mui ALF, Puil L, Pawson T, Krystal G. Phosphatidylinositol 3-kinase associates, via its Src homology 2 domains, with the activated erythropoietin receptor. Blood 81:3204–3210, 1996.[Abstract/Free Full Text]
62. Damen J, Cutler RL, Jiao H, Yi T, Krystal G. Phosphorylation of tyrosine 503 in the erythropoietin receptor (EpR) is essential for binding the p85 subunit of phosphatidylinositol (PI) 3-kinase and for EpR-associated PI 3-kinase activity. J Biol Chem 270:23402–23406, 1995.[Abstract/Free Full Text]
63. Verdier F, Chrtien S, Billat C, Gisselbrecht S, LaCombe C, Mayeux P. Erythropoietin induces the tyrosine phosphorylation of insulin receptor substrate-2: an alternate pathway for erythropoietin-induced phosphatidylinositol 3-kinase activation. J Biol Chem 272:26173–26178, 1997.[Abstract/Free Full Text]
64. Pallard C, Fabrice G, Martine C, Groner B, Gisselbrecht S, Dusanter-Fourt I. Interleukin-3, erythropoietin, and prolactin activate a STAT5 line factor in lymphoid cells. J Biol Chem 270:15942–15945, 1995.[Abstract/Free Full Text]
65. Wakao H, Harada N, Kitamura T, Mui ALF, Miyajima A. Interleukin 2 and erythropoietin activate STAT5/MGF via distinct pathways. EMBO J 14:2527–2535, 1995.[Medline]
66. Penta K, Sawyer ST. Erythropoietin induces the tyrosine phosphorylation nuclear translocation and DNA binding of STAT1 and STAT5 in erythroid cells. J Biol Chem 270:31282–31287, 1995.[Abstract/Free Full Text]
67. Watowich SS, Mikami A, Busche RA, Xie X, Pharr PN, Hongmore GD, Manduit P, Sabbah M, Druker B, Vainchenker W, Fisher S, Lacombe C, Gisselbreccht S. Erythropoietin receptors that signal through Stat5 or Stat3 support fetal liver and adult erythropoiesis: lack of specificity of STAT signals during Red Blood Cell Development. J Interferon Cytokine Res 20:1065–1070, 2000.[Medline]
68. Ihle JN. Cytokine receptor signaling. Nature 377:591–594, 1995.[Medline]
69. Damen JE, Wakao H, Miyajima A, Krosl J, Humphries RK, Cutler RL, Krystal G. Tyrosine 343 in the erythropoietin-receptor positively regulates erythropoietin-induced cell proliferation and STAT5 activation. EMBO J 14:5557–5568, 1995.[Medline]
70. Chrtien S, Varlet P, Verdier F, Gobert S, Cartron JP, Gisseelbrecht S, Mayeux P, LaCombe C. Erythropoietin-induced differentiation of the human erythroleukemia cell line TF-1 correlates with impaired STAT5 activation. EMBO J 15:4174–4181, 1996.[Medline]
71. Klingmuller U, Bergelson S, Hsiao JG, Lodish HC. Multiple tyrosine residues in the cytosolic domain of the erythropoietin receptor promote activation of STAT5. Proc Natl Acad Sci U S A 93:8324–8328, 1996.[Abstract/Free Full Text]
72. Quelle FW, Wang D, Nosaka T, Thierfelder WE, Stravopidis D, Weinstein Y, Ihle JN. Erythropoietin induces the activation of STAT5 through association with specific tyrosines on the receptor that are not required for a mitogenic response. Mol Cell Biol 16: 1622–1631, 1996.[Abstract]
73. Tauchi T, Damen JE, Toyama K, Feng GS, Broxmeyer HE, Krystal G. Tyrosine 426 within the activated erythropoietin receptor binds Syp reduces the erythropoietin required for Syp tyrosine phosphorylation and promotes mitogenesis. Blood 87:4495–4501, 1996.[Abstract/Free Full Text]
74. Klingmuller U, Lorenz U, Cantley LC, Neel BC, Lodish HC. Specific recruitment of SH-PTP1 to the erythropoietin receptor causes activation of JAK2 and termination of proliferative signals. Cell 80:729–738, 1995.[Medline]
75. Shan R, Price JO, Guarde WA, Monia BP, Krantz SB, Zhao ZJ. Distinct roles of JNKs/p38 MAP kinase and ERKs in apoptosis and survival of HCP-57 cells induced by withdrawal or addition of erythropoietin. Blood 94:4067–4076, 1999.[Abstract/Free Full Text]
76. Jacobs-Helber SM, Ryan SM, Sawyer JJ. JNK p38 are activated by erythropoietin in (EPO) but are not induced in apoptosis following EPO withdrawal in EPO-dependent HCD 57 cells. Blood 96:933–940, 2000.[Abstract/Free Full Text]
77. Krantz SB, Zhao ZJ. Retraction. Blood 97:843, 2001.[Free Full Text]
78. Semenza GL. Regulation of mammalian O₂ homeostasis by hypoxia-inducible factor 1. Annu Rev Cell Biol 15:551–578, 1999.[Medline]
79. Zhu H, Bunn HF. How do cells sense oxygen? Science 292:449–451, 2001.[Free Full Text]
80. Ivan M, Kondo K, Yang H, Kim W, Valiando J, Ohh M, Salic A, Asara JM, Lane WS, Kaclin WG Jr. HIF targeted for VHL-mediated destruction by proline hydroxylation: implications for O₂ sensing. Science 292:464–468, 2001.[Abstract/Free Full Text]
81. Jiang BH, Rue E, Wang GL, Roe R, Semenza GL. Dimerization, DNA binding, and transactivation properties of hypoxia-inducible factor 1. Am Soc Biochem Mol Biol 271:17771–17778, 1996.
82. Wang GL, Semenza GL. General involvement of hypoxia-inducible factor 1 in transcriptional responses to hypoxia. Proc Natl Acad Sci U S A 90:4304–4308, 1993.[Abstract/Free Full Text]
83. Semenza GL, Nejfelt Mkl, Chi SM, Antonarakis SE. Hypoxia-inducible nuclear factors bind to an enhancer element located 3' to the human erythropoietin gene. Proc Natl Acad Sci U S A 88:5680–5684, 1991.[Abstract/Free Full Text]
84. Beck I, Ramirez S, Weinmann R, Caro J. Enhancer element at the 3'-flanking region controls transcriptional response to hypoxia in the human erythropoietin gene. J Biol Chem 266:15563–15566, 1991.[Abstract/Free Full Text]
85. Semenza GL, Wang Gl. A nuclear factor induced by hypoxia via de novo protein synthesis binds to the human erythropoietin gene enhancer at a site required or transcriptional activation. Mol Cell Biol 12:5447–5454, 1992.[Abstract/Free Full Text]
86. Beck I, Weinmann R, Caro J. Characterization of hypoxia-responsive enhancer in the human erythropoietin gene shows presence of hypoxia-inducible 120-Kd nuclear DNA-binding protein in erythropoietin-producing and nonproducing cells. Blood 82:704–711, 1993.[Abstract/Free Full Text]
87. Wang GL, Semenza GL. Characterization of hypoxia-inducible factor 1 and regulation of DNA binding activity by hypoxia. J Biol Chem 268:21513–21518, 1993.[Abstract/Free Full Text]
88. Wang GL, Semenza GL. Purification and characterization of hypoxia-inducible factor 1. J Biol Chem 270:1230–1237, 1995.[Abstract/Free Full Text]
89. Hoffman EC, Reyes H, Chu FF, Sander F, Conley LH, Brooks BA, Hankisnon O. Cloning of a factor required for activity of the Ah (dioxin) receptor. Science 252:954–958, 1991.[Abstract/Free Full Text]
90. Goldberg MA, Dunning SP, Bunn HF. Regulation of the erythropoietin gene: evidence that the oxygen sensor is a heme protein. Science 242:1412–1415, 1988.[Abstract/Free Full Text]
91. Wang GL, Semenza GL. Desferrioxamine induces erythropoietin gene expression and hypoxia-inducible factor 1 DNA binding activity: implications for models of hypoxia signal transduction. Blood 82:3610–3615, 1993.[Abstract/Free Full Text]
92. Jiang B-H, Zheng JZ, Leung SW, Roe R, Semenza GL. Transactivation and inhibitory domains of hypoxia-inducible factor 1 : modulation of transcriptional activity by oxygen tension. J Biol Chem 272: 19253–19260, 1997.[Abstract/Free Full Text]
93. Chandel NS, Maltepe E, Goldwasser E, Mathieu CE, Simon MC, Schumacker PT. Mitochondrial reactive oxygen species trigger hypoxia-induced transcription. Proc Natl Acad Sci U S A 95:11715–11720, 1998.[Abstract/Free Full Text]
94. Fandrey J, Frede S, Ehleben W, Porwol T, Acker H, Jelkmann W. Cobalt chloride and desferrioxamine antagonize the inhibition of erythropoietin production by reactive oxygen species. Kidney Int 51: 492–496, 1997.[Medline]
95. Maxwell PH, Wiesener MS, Chang G-W, Clifford SC, Vaux EC, Cockman ME, Wykoff CC, Pugh CW, Maher EA, Ratcliffe PJ. The tumor suppressor protein VHL targets hypoxia-inducible factors for oxygen-dependent proteolysis. Nature 399:271–275, 1999.[Medline]
96. Liu Y, Christou H, Morita T, Laughner E, Semenza GL, Kourembanas S. Carbon monoxide and nitric oxide suppresses the hypoxic induction of vascular endothelial growth factor gene via the 5' enhances. J Biol Chem 273:15257–15262, 1998.[Abstract/Free Full Text]
97. Sogawa K, Numayama-Tsuruta K, Ema M, Abe M, Abe H, Fujii-Kuriyama Y. Inhibition of hypoxia-inducible factor 1 activity by nitric oxide donors in hypoxia. Proc Natl Acad Sci U S A 95:7368–7373, 1998.[Abstract/Free Full Text]
98. Gleadle JM, Ebert BL, Ratcliffe PJ. Diphenylene iodonium inhibits the induction of erythropoietin and other mammalian genes by hypoxia: implication for the mechanism of oxygen sensing. Eur J Biochem 234:92–99, 1995.[Medline]
99. Wang GL, Jiang B-H, Semenza GL. Effect of altered redox states on expression and DNA-binding activity of hypoxia-inducible factor 1. Biochem Biophys Res Commun 212:550–556, 1995.[Medline]
100. Jaakola P, Mole DR, Ya-Min Tian, Wilson MI, Glelburt J, Gaskett JJ, Von Kriegshelm A, Hebestreit HF, Mukerji M, Schofield D, Maxwell PH, Pregh CW, Ratcliffe PJ. Targeting of HIF- to the von hippel-lindau ubiquitylation complex by O₂-regulated prolyl hydroxylation. Science 292:468–472, 2001.[Abstract/Free Full Text]
101. Kivirikko KI, Pihlajaniemi I. Collagen hydroxylases and the protein disulfide isomerase subunit of polyl 4-hydroxylases. Adv Enzymol Relat Areas Mol Biol 72: 325–398, 1998[Medline]
102. Semenza GL. HIF-1 O₂ and 3 PHDs: how animal cells signal hypoxia to the nucleus. Cell 107:1–3, 2001.[Medline]
103. Ohh M, Park CW, Ivan M, Hoffman MA, Kim T-Y, Huang LE, Pavletich N, Chou V, Kaelin WG. Ubiquitination of hypoxia-inducible factor requires direct binding to the ß-domain of the von hipple-lindau protein. Nat Cell Biol 2:423–427, 2000.[Medline]
104. Masson N, William C, Maxwell PH, Pugh CW, Ratcliffe PJ. Independent function of two destruction domains in hypoxia-inducible factor- chains activated by prolyl hydroxylation. EMBO J 20:5197–5206, 2001.[Medline]
105. Epstein CRA, Gleadle JM, McNeill LA, Heurtson KS, O’Rourke J, Mole DR, Mukherji M, Metzern E, Wilson MI, Dhonda A, Tian Y-M, Masson N, Hamilton DL, Jaakkoal P, Barstead R, Hodgkin J, Maxwell PH, Pugh CW, Schofield CJ, Ratcliffe PJ. C. elegans EGL-9 and mammalian homologs define a family of dioxygenases that regulate HIF by prolyl hydroxylation. Cell 107:43–54, 2001.[Medline]
106. Bruick RK, McKnight SL. A conserved family of prolyl-4-hydroxylases that modify HIF. Science 294:1337–1340, 2001.[Abstract/Free Full Text]
107. Kallio PJ, Okamoto K, Obrien S, Carrero P, Makino Y, Tanaka H, Poellinger L. Signal transduction in hypoxic cells: inducible translocation and recruitment of the CBP/P300 coactivator by the hypoxia-inducible factor-1. EMBO J 17:6573–6586, 1998.[Medline]
108. Wang GL, Jiang B-H, Semenza GL. Effect of protein kinase and phosphatase inhibitors on expression of hypoxia-inducible factor 1. Biochem Biophys Res Commun 216:669–675, 1995.[Medline]
109. Kvietikova I, Wenger RH, Marti HH, Gassman M. The transcription factors ATF-1 and CREB-1 bind constitutively to the hypoxia-inducible factor-1 (HIF-1) DNA recognition site. Nucleic Acids Res 23:4542–4550, 1995.[Abstract/Free Full Text]
110. Ueno M, Brookins J, Beckman B, Fisher JW. A1 and A2 Adenosine receptor regulation of erythropoietin production. Life Sci 43:229–237, 1988.[Medline]
111. Mentzer RM Jr., Rubio R, Berne RM. Release of adenosine by hypoxic canine lung tissue and its possible role in pulmonary circulation. Am J Physiol 229:1625–1631, 1975.[Abstract/Free Full Text]
112. Minamino T, Kitakazo M, Komamura K, Node H, Takeda H, Inouse M, Hori M, Kamada T. Activation of protein kinase C increases adenosine production in the hypoxic canine coronary artery through the extracellular pathway. Arterioscler Thromb Vasc Biol 15:2298–2304, 1995.[Abstract/Free Full Text]
113. Kobayashi S, Millhorn DE. Stimulation of expression for the adenosine A_2A receptor gene by hypoxia in PC12 cells. A potential role in cell protection. J Biol Chem 274:20358–20365, 1999.[Abstract/Free Full Text]
114. Bakris GR, Sauter ER, Hussey JL, Fisher JW, Gaber AO, Winsett R. Effects of theophylline on erythropoietin production in normal subjects and in patients with erythrocytosis after renal transplantation. N Engl J Med 323:86–90, 1990.[Abstract]
115. Fisher JW, Brookins J. Adenosine A_2A and A_2B receptor activation of erythropoietin production. Am J Physiol 281:F826–F832, 2001.[Abstract/Free Full Text]
116. Nakashima J, Ohigashi T, Brookins JW, Beckman BS, Agrawal KC, Fisher JW. Effects of 5-N-ethylcarboxamideadenosine on erythropoietin production. Kidney Int 44:734–740, 1993.[Medline]
117. Ohigashi T, Nakashima J, Aggarwal S, Brookins J, Agrawal K, Fisher JW. Enhancement of erythropoietin production by selective adenosine A₂ recepton agonists in response to hypoxia. J Lab Clin Med 126:299–306, 1995.[Medline]
118. Feoktistov I, Biaggionni I. Adenosine A_2B receptors. Pharm Rev 49: 381–402, 1997.[Abstract/Free Full Text]
119. Yoshioka K, Clejan S, Brookins J, Fisher JW. Activation of protein kinase C in human hepatocellular carcinoma (HEP3B) cells increases erythropoietin production. Life Sci 63:523–535, 1998.[Medline]
120. McGary EC, Rondon IJ, Beckman BS. Post-transcriptional regulation of erythropoietin mRNA stability by eyrthropoietin mRNA-binding protein. Proc Natl Acad Sci U S A 88:5149–5153, 1997.[Abstract/Free Full Text]
121. Bouritius H, Bojvoth RB, Groot JA. Microelectrode measurements of the effects of basolateral adenosine in polarized human intestinal epithelial cells in culture. Pflugers Arch Eur J Physiol 437:589–595, 1999.[Medline]
122. Michoud MC, Tao FC, Pradham AA, Martin JG. Mechanisms of the potentiation by adenosine of adenosine triphosphate-induced calcium release in tracheal smooth muscle cells. Am J Resp Cell Mol Biol 21:30–36, 1999.[Abstract/Free Full Text]
123. Eschbach JW, Egrie JC, Downing MR, Browne JK, Adamson JW. Correction of the anemia of end-stage renal disease with recombinant human erythropoietin. N Engl J Med 316:73–78, 1987.[Abstract]
124. Eschbach J, DeOreo P, Adamson J, et al: rHuEPO clinical practice guidelines for the treatment of anemia of chronic renal failure. Am J Kidney Dis 30(Suppl 3):S192–S240, 1997.[Medline]
125. Eschbach JW. Current concepts of anemia management in chronic renal failure: impact of NKF-DOQI. Semin Nephrol 20:320–329, 2000.[Medline]
126. Kaufman JS, Reda DJ, Fye CL, Goldfarb D, Henderson WG, Kleinman JG, Vaamonde CA. Subcutaneous versus intravenous administration of erythropoietin in hemodialysis patients. N Engl J Med 339: 578–583, 1998.[Abstract/Free Full Text]
127. Egrie JC, Eschbach JW, McGuire T, Adamson JW. Pharmacokinetics of recombinant human erythropoietin administered to hemodialysis (HD) patients. Kidney Int 33:262, 1988.
128. Eschbach JW, Haley NR, Adamson JW. The use of recombinant erythropoietin in the treatment of the anemia of chronic renal failure. Ann NY Acad Sci 554:225–230, 1989.[Medline]
129. Jacobs C, Horl WH, Macdougal TC, Valderrabano F, Parrondo I, Segner A, Abraham TL. European best practice guidelines 5 target haemoglobin. Nephrol Dial Transplant 15(Suppl 4):15–19, 2000.[Free Full Text]
130. Fisher JW, Bommer J, Eschbach J, Fried W, Lange RD, Massry S, Nathan D, Nolph KD, Teehan BP. Statement on the clinical use of recombinant erythropoietin in anemia of end stage renal disease. Am J Kidney Dis 14:163–169, 1989.[Medline]
131. Murphy ST, Parfrey PS. Erythropoietin therapy in chronic anemia: the impact of normalization of hematocrit. Curr Opin Nephrol Hypertens 8:573–578, 1999.[Medline]
132. Kessler M. Value of early management of patients with chronic renal failure. Presse Medicale 26:1340–1342, 1997.
133. Ritz E, Eisenhart A. Early epoetin treatment in patients with renal insufficiency. Nephrol Dialysis Transplant 15(Suppl 3):40–44, 2000.[Abstract/Free Full Text]
134. Garcia MM, Beckman BS, Brookins JW, Powell JS, Lanham W, Blaisdell S, Keay L, Li SC, Fisher JW. Development of a new radioimmunoassay for EPO using recombinant erythropoietin. Kidney Int 38:969–975, 1990.[Medline]
135. McGonigle RJS, Boineau FG, Ohene-Frempong K, Lewy JE, Shadduck RK, Fisher JW. Erythropoietin and inhibitors of in vitro erythropoiesis in the development of anemia in children with renal disease. J Lab Clin Med 105:449–481, 1985.[Medline]
136. Radtke HW, Rege AB, Lamarche MB, Bartos D, Campbell RA, Fisher JW. Identification of spermine as an inhibitor of erythropoiesis in patients with chronic renal failure. J Clin Invest 67:1623–1629, 1980.
137. Macdougall IC. Role of uremic toxins in exacerbating anemia in renal failure. Kidney Int 59(Suppl 78):567–572, 2001.
138. Kushner DS, Beckman BS, Nguyen L, Chen S, Della Santina C, Husserl F, Rice J, Fisher JW. Poyamines in the anemia of end stage renal disease (ESRD). Kidney Int 39:725–732, 1991.[Medline]
139. Allen DA, Breen C, Yagoog MM, MacDougall IC. Inhibition of CFU-E colony formation in uremic patients with inflammatory disease: role of IFN- and TNF-. J Invest Med 47:204–211, 1999.[Medline]
140. Erslev AJ, Besareb A. The rate and control of baseline red cell production in hematologically stable patients with uremia. J Lab Clin Med 126:283–286, 1995.[Medline]
141. Steiner RW. Characteristics of the hematocrit response to continuous ambulatory dialysis. Arch Intern Med 144:728–732, 1984.[Abstract/Free Full Text]
142. McGonigle RJS, Husserl F, Wallin JD, Fisher JW. Hemodialysis and continuous ambulatory peritoneal dialysis effect on erythropoiesis in renal failure. Kidney Int 25:430–436, 1984.[Medline]
143. Vaziri NA. Cardiovascular effects of erythropoietin and anemia correction. Curr Opin Nephrol Hypertens 10:633–637, 2001.[Medline]
144. Vaziri ND, Zhou XJ, Naqui F, Smith J, Oveisi F, Wang ZQ. Role of nitric oxide resistance in erythropoietin-induced hypertension in rats with chronic renal failure. Am J Physiol 271:E113–E122, 1996.[Abstract/Free Full Text]
145. Koupke CJ, Kim S, Vaziri ND. Effect of erythrocyte mass on arterial blood pressure in dialysis patients receiving maintenance erythropoietin therapy. J Am Soc Nephrol 4:1874–1878, 1994.[Abstract]
146. Vaziri ND, Zhou M, Smith J, Oveisi F, Baldwin K, Purdy RD. In vivo and in vitro pressor effects of erythropoietin in rats. Am J Physiol 269:F838–F845, 1995.[Abstract/Free Full Text]
147. Bode-Boger SM, Boger RH, Kahn M, Rodermacher J, Frohlich JC. Recombinant erythropoietin enhances vasoconstriction tone via endothelin-1 and constrictor prostanoids. Kidney Int 50:1255–1261, 1996.[Medline]
148. Brochu E, Lacasses S, Lariviere R, Kingma I, Grose JH, Lebel M. Differential effects of endothelin-1 antagonists on erythropoietin-induced hypertension in renal failure. J Am Soc Nephrol 10:1440–1446, 1999.[Abstract/Free Full Text]
149. Eggena P, Willsey P, Jarngotchian N, Truckenbrod L, Barrett JD, Eggena MP, Clegg K, Nakhoul F, Lee DBN. Influence of recombinant human erythropoietin on blood pressure and tissue renin-angiotensin systems. Am J Physiol 261:E642–E646, 1991.[Abstract/Free Full Text]
150. Bode-Boger SM, Boger RH, Kuhn M. Endothelin release and shift in prostaglandin balance are involved in the modulation of vascular tone by recombinant erythropoietin. J Cardiovasc Pharmacol20(Suppl 12): 525–528, 1992.[Medline]
151. Pelletier L, Regnard J, Fellman D, Chrarbord P. An in vitro model for the study of human marrow angiogenesis: role of hematopoietic cytokines. Lab Investig 80:501–511, 2000.[Medline]
152. Ribatti D, Presta M, Vasca A, Giuliani RR, Dell’Era P, Roncali NB, Dammaco F. Human erythropoietin induces a pro-angiogenic phenotype in cultured endothelial cells and stimulates neovascularization in vivo. Blood 93:2627–2636, 1999.[Abstract/Free Full Text]
153. Carlini RG, Reyes AA, Rothstein M. Recombinant human erythropoietin stimulates angiogenesis in vitro. Kidney Int 47:740–745, 1995.[Medline]
154. Iimura O, Takahoshi H, Ikeda H, Ito G, Ando Y, Ozawa K, Asano Y, Akimato T, Kiusano E, Inoba TV. Erythropoietin regulates vascular smooth muscle cell apoptosis by a phosphotidylinositol 3 kinase-dependent pathway. Kidney Int 58:269–282, 2000.[Medline]
155. Jereen-Sturgic B, Race V, Jeren T, Horavatin-Golder S. Morphologic and functional changes of left ventricle in dialyzed patients after treatment with recombinant human erythropoietin. Angiology 51: 131–139, 2000.
156. Wagner KF, Katschinski DM, Hasegawa J, Schumacher D, Meller B, Gembruck V, Schramm V, Jelkmann W, Gassmann M, Fandrey J. Chronic inborn erythrocytosis leads to cardiac dysfunction and premature death in mice overexpressing erythropoietin. Blood 97:536–542, 2001.[Abstract/Free Full Text]
157. Casadevall N, Nataf J, Viron B, Kolta A, Kiladjian J-J, Dupont PM, Michaud P, Papo T, Ugo V, Teyssander I, Varet B, Mayeux P. Pure red cell aplasia and antierythropoietin antibodies in patients treated with recombinant erythropoietin. N Engl J Med 346:469–475, 2002.[Abstract/Free Full Text]
158. Gogue SR, Beckman BS, Wilson RB, Agrawal KS. Inhibitory effects of zidovudine in erythroid progenitor cells. Reversal with a combination of erythropoietin and interleukin-3. Biochem Pharmacol 50: 413–419, 1995.[Medline]
159. Henry DH, Beal GN, Benson CA, Cary J, Cone LA. Recombinant human erythropoietin in the treatment of anemia associated with human immunodeficiency virus (HIV) infection and zidovudine therapy. Ann Int Med 117:730–748, 1992.
160. Fischl M, Galpin JE, Levine JL, Groopman JE, Henry DH, Kennedy P, Miles S, Robbins W, Starrett B, Zalusky R, Abels RI, Tsai HC, Rudnick SA. Recombinant human erythropoietin for patients with AIDS treated with zidovudine. N Engl J Med. 322:1488–1493, 1990.[Abstract]
161. Smith DH, Guaneri CM, Whaling SM, Vokes EE. Erythropoietin response in cancer patients receiving cisplatin. Proc Am Assoc Cancer Res 29:52, 1988.
162. Gabrilove JL, Cleeland CS, Livingston RB, Sarakham B, Winer E, Einhorn LH. Clinical evaluation of once-weekly dosing of epoetin- in chemotherapy patients: Improvements in hemoglobin and quality of life are similar to three times weekly dosing. J Clin Oncol 19: 2875–2882, 2001.[Abstract/Free Full Text]
163. Vercameen E, Rappaport B. Effects of epoetin- on hematologic parameters and quality of life in cancer patients receiving nonplatinum chemotherapy: results of a randomized, double-blind, placebo-controlled trial. J Clin Oncol 19:2865–2874, 2001.[Abstract/Free Full Text]
164. De Andrade JR, Jove M. Baseline hemoglobin as a predictor of risk of transfusion and response to epoetin- in patients undergoing major orthopedic surgery. Am J Orthoped 25:533–546, 1996.
165. Goldberg MA, McCutchen JW. A safety and efficacy comparison study of two dosing regimens of epoetin- in patients undergoing major orthopedic surgery. Am J Orthoped 25:544–552, 1996.
166. Di Raimondo F, Longo G, Cacciola EJR, Milone G, Palumbo GA, Cacciola RR, Alessi M, Giustolisi R. A good response rate to recombinant erythropoietin alone may be expected in selected myelodysplastic patients. A preliminary clinical study. Eur J Haematol 56: 7–11, 1996.[Medline]
167. Thomas MJG, Gillon J, Desmond MJ. Preoperative autologous donation. Transfusion 36:633–639, 1996.[Medline]
168. Price TR, Goodnough LT, Vogler WR, Sacher RA, Hellman RM, Johnston MFM, Bolgiano DC, Abels RI. The effect of recombinant human erythropoietin on the efficacy of autologous blood donation in patients with low hematocrits: a multicenter, randomized, double-blind, controlled trial. Transfusion 36:29–31, 1996.[Medline]
169. Harris SA, Payne G Jr., Putman JM. Erythropoietin treatment of erythropoietin-deficient anemia without renal disease during pregnancy. Obstet Gynecol 87:812–814, 1996.[Medline]
170. Pincus T, Olsen NJ, Russel IJ, Eolfe F, Harms RE. Multicenter study of recombinant human erythropoietin in correction of anemia in rheumatoid arthritis. Am J Med 89:161–168, 1990.[Medline]
171. Messer J, Haddad J, Donato L, Astruc D, Matis J. Early treatment of premature infants with recombinant human erythropoietin. Pediatrics 92:519–523, 1993.[Abstract/Free Full Text]
172. Bader B, Blondhein O, Jona R, Admoni O, Abend-Winger M, Reich D, Lanis A, Tamier A, Eldar T, Attias D. Decreased ferritin levels despite iron supplementation, and during therapy in the anemia of prematurity. Acta Paediatr 85:496–501, 1996.[Medline]
173. Steegman JL, Lopez J, Otero MJ, Lamana ML, de la Cámara R, Barberana M, Diaz A, Ferande-Ranada JM. Erythropoietin treatment in allogeneic BMT accelerates erythroid reconstitution: results of a prospective controlled randomized trial. Bone Marrow Transplant 10:541–546, 1992.[Medline]
174. Pierelli L, Scambia G, Menichella G, d’Onofrio G, Slerno G, Panici PB, Foddai ML, Vittori M, Lai M, Ciarli M, Puglia G, Mancuso S, Bizzi B. The combination of erythropoietin and granulocyte colony-stimulating factor increases the rate of haemopoietic recovery with clinical benefit after peripheral blood progenitor cell transplantation. Br J Haematol 92:287–294, 1996.[Medline]
175. Goodnough LT, Anderson KC, Kurtz S, Lane TA, Pisciotto PT, Silverstein LE. Indications and guidelines for the use of hematopoietic growth factors. Committee Rep Transfus 33:944–955, 1993.
176. Eschbach JW, Abdulhadi MH, Browne JK, Delano BG. Recombinant human erythropoietin in anemic patients with end-stage renal disease. Results of a phase III multicenter clinical trial. Ann Int Med 111: 992–1000, 1989.
177. Egrie JC, Grant JR, Gillies DK. The role of the carbohydrate on the biological activity of erythopoietin. Glycoconjugate J 10:263, 1993.
178. Macdougall IC, Gray SJ, Elston O, Breen C, Jenkins B, Browne J, Egrie J. Pharmacokinetics of novel erythropoieis protein compared with epoetin- in dialysis patients. J Am Soc Nephrol 10:2392–2395, 1999.[Abstract/Free Full Text]
179. Macdougall IC. An overview of the efficacy and safety of novel erythropoiesis stimulating protein (NESP). Nephrol Dialysis Transplant 16(Suppl 3):14–21, 2001.[Free Full Text]
180. Locatelli F, Olivares J, Walker R, Wilkie M, Jenkins B, Dewey C, Gray SJ. Novel erythropoiesis stimulating protein for treatment of anemia in chronic renal insufficiency. Kidney Int 60:741–747, 2001.[Medline]
181. Macdougall IC, Roberts DE, Coles GA, Williams JD. Clinical pharmacokinetics of epoetin (recombinant human erthropoietin). Clin Pharmacokinetics 20:99–113, 1991.[Medline]
182. Macdougall IC, Gary SJ, Elston O, Breen C, Jenkins B, Browne J, Egrie J. Pharmacokinetics of novel erythropoiesis stimulating protein compared with epoetin- in dialysis patients. J Am Soc Nephrol 10: 2392–2395, 1999.
183. Macdougall IC, on behalf of the UK NESP Study Guide. Novel erythropoiesis stimulating protein (NESP) for the treatment of renal anemia. J Am Soc Nephrol 9:258A–259A, 1998.
184. Korbert SM. Anemia and erythropoietin in hemodialysis and continuous ambulatory peritoneal dialysis. Kidney Int 43:S111–S119, 1993.
185. Vanrenterghem Y, Barany P, Mann J. Novel erythropoiesis stimulating protein (NESP) maintains hemoglobin in ESRD patients when administered once-weekly or once every other week. J Am Soc Nephrol 10:270A, 1999.
186. The Medical Letter on Drugs and Therapeutics. Darbepoetin (ARANESP) = a long-acting erythropoietin. Rochelle, NY: The Medical Letter, Inc. Vol. 43(1120) pp 109–110, 2001.
187. Pace N. The increase in hypoxia tolerance of normal men accompanying the polycythemia induced by transfusion of erythocytes. Am J Physiol 148:152–163, 1947.[Free Full Text]
188. Ekblom B, Goldbard AN, Gullbring B. Response to exercise after blood loss and reinfusion. J Appl Physiol 33:175–180, 1972.[Free Full Text]
189. Ekblom B, Berglund B. Effect of erythropoietin administration on maximal aerobic power. Scand J Med Sci Sports 1:88–93, 1991.
190. Jelkmann W. Use of recombinant human erythropoietin as an antianemic and performance enhancing drug. Curr Pharmaceut Biotechnol 1:11–31, 2000.
191. Jelkmann W. Beneficial and adverse effects of erythropoietin therapy. In: Peters C, Schulz T, Michnam H, Druck, Eds. Biomedical Side Effects of Doping. Germany: Hansen, Bergisch Gladbach, pp59–73, 2001.
192. Shaskey DJ, Green GA. Sports haematology. Sports Med 29:27–38, 2000.[Medline]
193. Breymann C. Erythropoietin test methods. Best Practice Res Clin Endocrinol Metab 14:135–145, 2000.
194. Sieff CA, Nathan DG. Haemopoietic stem cells. In: Weatherall DJ, Ledingham JGG, Warren DA, Eds. Oxford Textbook of Medicine (3rd ed). Oxford, UK: Oxford University Press, pp3381–3390, 1996.
195. Marti HH, Bernaudin M. Function of erythropoietin in the brain. In: Wolfgang J, Ed. Erythropoietin: Molecular Biology and Clinical Use. Johnson City, Tennessee: F. P. Graham Publishing Co., pp 195–215, 2002.
196. Juul S. Erythropoietin in the central nervous system and its use to prevent hypoxic-ischemic brain damage. Acta Paediatr 438(Suppl):36–42, 2002.

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				F. Scalera, J. T. Kielstein, J. Martens-Lobenhoffer, S. C. Postel, M. Tager, and S. M. Bode-Boger Erythropoietin Increases Asymmetric Dimethylarginine in Endothelial Cells: Role of Dimethylarginine Dimethylaminohydrolase J. Am. Soc. Nephrol., April 1, 2005; 16(4): 892 - 898. [Abstract] [Full Text] [PDF]

				T. Rui, Q. Feng, M. Lei, T. Peng, J. Zhang, M. Xu, E. Dale Abel, A. Xenocostas, and P. R. Kvietys Erythropoietin prevents the acute myocardial inflammatory response induced by ischemia/reperfusion via induction of AP-1 Cardiovasc Res, February 15, 2005; 65(3): 719 - 727. [Abstract] [Full Text] [PDF]

				B. B. Beleslin-Cokic, V. P. Cokic, X. Yu, B. B. Weksler, A. N. Schechter, and C. T. Noguchi Erythropoietin and hypoxia stimulate erythropoietin receptor and nitric oxide production by endothelial cells Blood, October 1, 2004; 104(7): 2073 - 2080. [Abstract] [Full Text] [PDF]

				C. Waskow, G. Terszowski, C. Costa, M. Gassmann, and H.-R. Rodewald Rescue of lethal c-KitW/W mice by erythropoietin Blood, September 15, 2004; 104(6): 1688 - 1695. [Abstract] [Full Text] [PDF]

				H. H. Marti Erythropoietin and the hypoxic brain J. Exp. Biol., August 15, 2004; 207(18): 3233 - 3242. [Abstract] [Full Text] [PDF]

				M. A Bogoyevitch An update on the cardiac effects of erythropoietin cardioprotection by erythropoietin and the lessons learnt from studies in neuroprotection Cardiovasc Res, August 1, 2004; 63(2): 208 - 216. [Abstract] [Full Text] [PDF]

				V. R. Gordeuk, A. I. Sergueeva, G. Y. Miasnikova, D. Okhotin, Y. Voloshin, P. L. Choyke, J. A. Butman, K. Jedlickova, J. T. Prchal, and L. A. Polyakova Congenital disorder of oxygen sensing: association of the homozygous Chuvash polycythemia VHL mutation with thrombosis and vascular abnormalities but not tumors Blood, May 15, 2004; 103(10): 3924 - 3932. [Abstract] [Full Text] [PDF]

				G. Grasso, A. Sfacteria, A. Cerami, and M. Brines Erythropoietin as a Tissue-Protective Cytokine in Brain Injury: What Do We Know and Where Do We Go? Neuroscientist, April 1, 2004; 10(2): 93 - 98. [Abstract] [PDF]

				J. A. Rillema Hormone Regulation of Choline Uptake and Incorporation in Mouse Mammary Gland Explants Experimental Biology and Medicine, April 1, 2004; 229(4): 323 - 326. [Abstract] [Full Text] [PDF]

				S. Erbayraktar, G. Grasso, A. Sfacteria, Q.-w. Xie, T. Coleman, M. Kreilgaard, L. Torup, T. Sager, Z. Erbayraktar, N. Gokmen, et al. Asialoerythropoietin is a nonerythropoietic cytokine with broad neuroprotective activity in vivo PNAS, May 27, 2003; 100(11): 6741 - 6746. [Abstract] [Full Text] [PDF]

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