Stimulating erythropoiesis in inflammatory bowel disease associated anemia

Anemia is a frequent complication in patients with inflammatory bowel disease (IBD), and is associated with decreased quality of life and increased rate of hospitalization. The primary therapeutic targets of IBD- associated anemia are iron deficiency and anemia of chronic disease. An important prognostic parameter of the success or failure of therapy is the outcome of the underlying disease. Iron deficiency should be appropriately managed with iron supplementation. However, the use of oral iron therapy is limited by several problems, the most important being gastrointestinal side effects leading occasionally to disease relapse and poor iron absorption. Intravenous iron preparations are more reliable, with iron sucrose demonstrating the best efficacy and tolerability. Treatment with erythropoietin or darbepoetin has been proven to be effective in patients with anemia, who fail to respond to intravenous iron. Patients with ongoing inflammation have anemia of chronic disease and may require combination therapy comprising of intravenous iron sucrose and erythropoietin. After initiating treatment, careful monitoring of hemoglobin levels and iron parameters is needed in order to avoid recurrence of anemia. In conclusion, anemia in the setting of IBD should be aggressively diagnosed, investigated, and treated. Future studies should define the optimal dose and schedule of intravenous iron supplementation and appropriate erythropoietin therapy in these patients.

The Cloning of Erythropoiesis-related Genes with the Innovated Model System

Most studies of erythropoiesis have been performed either with the virally transformed MEL cells or with the scarce erythroblasts within unhomogeneous cell populations.MEL cells are the Friend virus transformed mouse erythroleukemia cells and have lost the capacity to respond to erythropoietin.Moreover,the research in the field of erythropoiesis has been severely hampered by the paucity of erythroblasts obtained from chick embryos,human,mouse,rat fetal liver,mouse spleen,or the bone marrow.In our paper,the fetal blood from newly slaughtered pregnant sheep meets the needs of studies as abundant staring biological materials at the nucleotide level and also reflects in vivo proliferative and differential status of erythroblasts.Appling the technique of mRNA differential display with minor modification,we directly compared cDNA fragmerts from the fetal blood erythroblasts and adult pregnant sheep leukocytes by PCR on DNA sequencing gels and revealed two differentially expressing bands.One is a novel gene fragment, which has homology with UV-sensitive cone opsin or rhodopsin by examinating the predicted amino acid sequence.Since the blood cells are sensitive to radiation,it can be safely inferred that this fragment participate in the process of cytocidal effect of the radiation.The other fragment is glucose induced gene /elongation factor 2 3′end noncoding region,which was first cloned from glucose induced bovine aortic smooth muscle cells.Using Northern blot hybridization method,authentic specific expression was confirmed.

Cell cycle.independent roles of p19INK4d in human terminal erythropoiesis

Normally, cyclin interacts with cyclin-dependent kinase (CDK) to form a cyclin-CDK complex, which promotes cell cycle progression, whereas cyclin-dependent kinase inhibitor (CDKI) molecules inhibit the formation of cyclin- CDK complex, arresting cell cycle. Terminal erythropoiesis is closely coordinated with cell cycle exit, which is regulated by cyclins, CDKs, and CDKIs [1]. In the global transcriptome of human terminal erythropoiesis [2], p19INK4d is expressed highly, and its expression is significantly up-regulated during human terminal erythropoiesis. However, the roles of p19INK4d in terminal erythropoiesis are still unknown.

Erythropoiesis Stimulating Agents (ESAs) in the Treatment of Cardio-Renal Syndrome Anaemia

Coexistence of chronic kidney disease (CKD) and chronic heart failure (CHF) define a recently recognized clinical entity known as cardio-renal syndrome. Sufficient evidence suggests that the two pathological conditions share common pathogenic etiology which is not yet fully defined. Superimposed anaemia is a common finding among patients suffering from cardio-renal syndrome. The combination of CKD, CHF and anaemia increase the probability of death by 6 times compared to normal individuals. Early attempts to restore anaemia either by iron supplementation, erythropoiesis stimulating agents (ESAs) or combination of the two have reported to improve quality of life, morbidity and mortality especially among patients treated by cardiologists. Recent publications of well controlled epidemiological studies failed to prove convincing beneficial effect of the above mentioned therapy moreover skepticism has raised concerning the safety of restoring anaemia among patients with cardio-renal syndrome as well as used medications. There are still unresolved problems concerning the definition of anaemia, by means of hemoglobin level among these patients, the target hemoglobin level and the therapeutic regimen of ESAs administration and iron supplementation. We need much more evidence in order to define an effective and safe treatment strategy correcting anaemia among patients with cardio-renal syndrome.

Iron-Restricted Erythropoiesis in Anaemic Patients with Giant Cell Arteritis and Polymyalgia Rheumatica

The aim of this observational study was to biochemically characterize the anaemia in GCA (giant cell arteritis) and PMR (polymyalgia rheumatica) patients. Values for mean corpuscular volume, mean corpuscular hemoglobin and soluble transferrin receptor were normal, whereas serum iron and total iron binding capacity (TIBC) were subnormal, and mean ferritin was above the upper reference limit. Iron-restricted erythropoiesis (IRE), defined as a bone marrow smear staining positive for iron in combination with transferrin saturation less than 20%, was present in all patients. All patients exhibited clinical and biochemical signs of active inflammation with elevated C-reactive protein and an increased erythrocyte sedimentation rate.

In vivo bioassay to determine the potency of a new erythropoiesis stimulating protein

A simple in vivo bioassay suitable for the routine quality control testing of a new erythropoiesis stimulating protein was developed.Subcutaneous administration of the new erythropoiesis stimulating protein to Balb/c mice in a single dose resulted in a dose-dependent increase in the number of circulating reticulocytes.Within the erythropoiesis stimulating protein dose range of 3.125 to 200 ng per mouse,there is a strong linear relationship between the dose and reticulocyte counts in the treated mice.This linear relationship allows us to determine the biological potency of the testing erythropoiesis stimulating protein preparation relative to a reference standard using parallel line assay.Accuracy,precision,dose variation and blood collection time of this method were analyzed in order to choose doses in the linear range that are suitable for setting up a useful,precise,and economical bioassay.

Post-transcriptional regulation of erythropoiesis

Erythropoiesis is a complex,precise,and lifelong process that is essential for maintaining normal body functions.Its strict regulation is necessary to prevent a variety of blood diseases.Normal erythropoiesis is precisely regulated by an intricate network that involves transcription levels,signal transduction,and various epigenetic modifications.In recent years,research on posttranscriptional levels in erythropoiesis has expanded significantly.The dynamic regulation of splicing transitions is responsible for changes in protein isoform expression that add new functions beneficial for erythropoiesis.RNA-binding proteins adapt the translation of transcripts to the protein requirements of the cell,yielding mRNA with dynamic translation efficiency.Noncoding RNAs,such as microRNAs and lncRNAs,are indispensable for changing the translational efficiency and/or stability of targeted mRNAs to maintain the normal expression of genes related to erythropoiesis.N6-methyladenosine-dependent regulation of mRNA translation plays an important role in maintaining the expression programs of erythroid-related genes and promoting erythroid lineage determination.This review aims to describe our current understanding of the role of post-transcriptional regulation in erythropoiesis and erythroid-associated diseases,and to shed light on the physiological and pathological implications of the post-transcriptional regulation machinery in erythropoiesis.These may help to further enrich our understanding of the regulatory network of erythropoiesis and provide new strategies for the diagnosis and treatment of erythroid-related diseases.

Long non-coding RNAs during normal erythropoiesis

The transcription of essentially the entire eukaryotic genome produces a huge amount of non-coding RNAs.Among them,long noncoding RNAs(lncRNAs)consist of a significant portion that widely exists across mammal genome,generating from high-throughput transcriptomic studies in the last decade.Although the functions of most lncRNAs remain to be further investigated,many of them have already been shown to play critical roles during normal development and disease conditions.Increasing evidence indicates that lncRNAs involve in versatile biological processes during erythroid proliferation and differentiation,including erythroid cell survival,heme metabolism,globin switching and regulation,erythroid enucleation,etc,via cis-or trans-mediated molecular mechanisms.In this review,we focus on recent advances regarding the functions and mechanisms of lncRNAs in normal erythropoiesis.

Novel methods for studying normal and disordered erythropoiesis

Erythropoiesis is a process during which multipotential hematopoietic stem cells proliferate, differentiate and eventually form mature erythrocytes. Interestingly, unlike most cell types, an important feature of erythropoiesis is that following each mitosis the daughter cells are morphologically and functionally different from the parent cell from which they are derived, demonstrating the need to study erythropoiesis in a stage-specific manner. This has been impossible until recently due to lack of methods for isolating erythroid cells at each distinct developmental stage. This review summarizes recent advances in the development of methods for isolating both murine and human erythroid cells and their applications. These methods provide powerful means for studying normal and impaired erythropoiesis associated with hematological disorders.

Crosstalk between catecholamines and erythropoiesis

BACKGROUND： Erythropoiesis is regulated by a range of intrinsic and extrinsic factors, including different cytokines. Recently, the role of catecholamines has been highlighted in the development of erythroid cell lineages. OBJECTIVE： This study focuses on the biological links interconnecting erythroid development and the sympathetic nervous system. The emerging evidence that underscores the role of catecholamines in the regulation of erythropoietin and other erythropoiesis cytokines are thoroughly reviewed, in addition to elements such as iron and the leptin hormone that are involved in erythropoiesis. METHODS： Relevant English-language studies were identified and retrieved from the PubMed search engine （1981-2017） using the following keywords： ＂Erythropoiesis＂, ＂Catecholamines＂, ＂Nervous system＂, and ＂Cytokines.＂ RESULTS： Chronic social stress alters and suppresses erythroid development. However, the physiological release of catecholamines is an additional stimulator of erythropoiesis in the setting of anemia. Therefore, the severity and timing of catecholamine secretion might distinctly regulate erythroid homeostasis. CONCLUSION： Understanding the relationship of catecholamines with different elements of the erythroid islands will be essential to find the tightly regulated production of red blood cells （RBCs） in both chronic and physiological catecholamine activation.

Comprehensive Characterization and Global Transcriptome Analysis of Human Fetal Liver Terminal Erythropoiesis

The fetal liver(FL)is the key erythropoietic organ during fetal development,but knowledge on human FL erythropoiesis is very limited.In this study,we sorted primary erythroblasts from FL cells and performed RNA sequencing(RNA-seq)analyses.We found that temporal gene expression patterns reflected changes in function during primary human FL terminal erythropoiesis.Notably,the expression of genes enriched in proteolysis and autophagy was up-regulated in orthochromatic erythroblasts(OrthoEs),suggesting the involvement of these pathways in enucleation.We also performed RNA-seq of in vitro cultured erythroblasts derived from FL CD34+cells.Comparison of transcriptomes between the primary and cultured erythroblasts revealed significant differences,indicating impacts of the culture system on gene expression.Notably,the expression of lipid metabolism-related genes was increased in cultured erythroblasts.We further immortalized erythroid cell lines from FL and cord blood(CB)CD34+cells(FL-iEry and CB-iEry,respectively).FL-iEry and CB-iEry were immortalized at the proerythroblast stage and can be induced to differentiate into OrthoEs,but their enucleation ability was very low.Comparison of the transcriptomes between OrthoEs with and without enucleation capability revealed the down-regulation of pathways involved in chromatin organization and mitophagy in OrthoEs without enucleation capacity,indicating that defects in chromatin organization and mitophagy contribute to the inability of OrthoEs to enucleate.Additionally,the expression of HBE1,HBZ,and HBG2 was up-regulated in FL-iEry compared with CB-iEry,and such up-regulation was accompanied by down-regulated expression of BCL11A and up-regulated expression of LIN28B and IGF2BP1.Our study provides new insights into human FL erythropoiesis and rich resources for future studies.

MicroRNAs in erythropoiesis and red blood cell disorders

MicroRNAs （miRNAs） are 19-24 nucleotide non-coding ribonucleic acids binding DNA or RNA and controlling gene expression via mRNA degradation or its transcription inhibition. Erythropoies is a multi step differentiation process of erythroid progenitors to nucleate red blood cells. Maturation, proliferation and differentiation of red blood cells is affected by erythroid factors, signaling pathways in niche of hematopoietic cells, transcription factors as well as miRNAs. Expression of different types of miRNAs during erythroid development provides a background for the study of these molecules to control erythroid differentiation and maturation as well as their use as diagnostic and prognostic markers to treat erythroid disorders like thalassemia, sickle cell disease and erythrocyte enzyme deficiencies. In this paper, with reference to biosynthesis of miRNAs, their function in normal and anemic erythropoiesis has been investigated. The target molecule of each of these miRNAs has been cited in an attempt to elucidate their role in erythropoiesis.

Zebrafish ELL-associated factors Eaf1/2 modulate erythropoiesis via regulating gata1a expression and WNT signaling to facilitate hypoxia tolerance

EAF1 and EAF2,the eleven-nineteen lysine-rich leukemia(ELL)-associated factors which can assemble to the super elongation complex(AFF1/4,AF9/ENL,ELL,and P-TEFb),are reported to participate in RNA polymeraseⅡto actively regulate a variety of biological processes,including leukemia and embryogenesis,but whether and how EAF1/2 function in hematopoietic system related hypoxia tolerance during embryogenesis remains unclear.Here,we unveiled that deletion of EAF1/2(eaf1^(-/-)and eaf2^(-/-))caused reduction in hypoxia tolerance in zebrafish,leading to reduced erythropoiesis during hematopoietic processes.Meanwhile,eaf1^(-/-)and eaf2^(-/-)mutants showed significant reduc-tion in the expression of key transcriptional regulators scl,lmo2,and gata1a in erythropoiesis at both 24 h post fertilization(hpf)and 72 hpf,with gata1a downregulated while scl and lmo2 upregulated at 14 hpf.Mechanistically,eaf1^(-/-)and eaf2^(-/-)mutants exhibited significant changes in the expression of epigenetic modified histones,with a significant increase in the binding enrichment of modified histone H3K27me3 in gata1a promoter rather than scl and lmo2 promoters.Additionally,eaf1^(-/-)and eaf2^(-/-)mutants exhibited a dynamic expression of canonical WNT/β-catenin signaling during erythropoiesis,with significant reduction in p-β-Catenin level and in the binding enrichment of both scl and lmo2 promoters with the WNT transcriptional factor TCF4 at 24 hpf.These findings demonstrate an important role of Eaf1/2 in erythropoiesis in zebrafish and may have shed some light on regeneration medicine for anemia and related diseases and on molecular basis for fish economic or productive traits,such as growth,disease resistance,hypoxia tolerance,and so on.

Perioperative anemia management in colorectal cancer patients:A pragmatic approach

Anemia,usually due to iron deficiency,is highly prevalent among patients with colorectal cancer.Inflammatory cytokines lead to iron restricted erythropoiesis further decreasing iron availability and impairing iron utilization.Preoperative anemia predicts for decreased survival.Allogeneic blood transfusion is widely used to correct anemia and is associated with poorer surgical outcomes,increased post-operative nosocomial infections,longer hospital stays,increased rates of cancer recurrence and perioperative venous thromboembolism.Infections are more likely to occur in those with low preoperative serum ferritin level compared to those with normal levels.A multidisciplinary,multimodal,individualized strategy,collectively termed Patient Blood Management,minimizes or eliminates allogeneic blood transfusion.This includes restrictive transfusion policy,thromboprophylaxis and anemia management to improve outcomes.Normalization of preoperative hemoglobin levels is a World Health Organization recommendation.Iron repletion should be routinely ordered when indicated.Oral iron is poorly tolerated with low adherence based on published evidence.Intravenous iron is safe and effective but is frequently avoided due to misinformation and misinterpretation concerning the incidence and clinical nature of minor infusion reactions.Serious adverse events with intravenous iron are extremely rare.Newer formulations allow complete replacement dosing in 15-60 min markedly facilitating care.Erythropoiesis stimulating agents may improve response rates.A multidisciplinary,multimodal,individualized strategy,collectively termed Patient Blood Management used to minimize or eliminate allogeneic blood transfusion is indicated to improve outcomes.

Hepcidin modulation in human diseases: From research to clinic

By modulating hepcidin production, an organism controls intestinal iron absorption, iron uptake and mobilization from stores to meet body iron need. In recent years there has been important advancement in our knowledge of hepcidin regulation that also has implications for understanding the physiopathology of some human disorders. Since the discovery of hepcidin and the demonstration of its pivotal role in iron homeostasis, there has been a substantial interest in developing a reliable assay of the hormone in biological fluids. Measurement of hepcidin in biological fluids can improve our understanding of iron diseases and be a useful tool for diagnosis and clinical management of these disorders. We reviewed the literature and our own research on hepcidin to give an updated status of the situation in this rapidly evolving field.

Stem cell autotomy and niche interaction in different systems

The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes(platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells(GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells(homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche(hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion(E-cadherin) and the direction of asymmetrical GSC division- as they were found in Drosophila- can hardly be translated into the systems where GSC autotomywas reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon pruning and dying-back degeneration in neurodegenerative diseases. Especially the hypothesis of an existing evolutionary conserved "autodestruction program" in axons that might also be active in GSC projections appears attractive. Investigations on the underlying signaling pathways have to be carried out. There are two other well known cases of programmed cell autotomy: the enucleation of erythroblasts in the process of erythrocyte maturation and the segregation of thousands of thrombocytes(platelets) from one megakaryocyte. Both progenitor cell types- erythroblasts and megakaryocytes- are associated with a niche in the bone marrow, erythroblasts with a macrophage, which they surround, and the megakaryocytes with the endothelial cells of sinusoids and their extracellular matrix. Although the regulatory mechanisms may be specific in each case, there is one aspect that connects all described processes of programmed cell autotomy and neuronal autodestruction: apoptotic pathways play always a prominent role. Studies on the role of male GSC autotomy in stem cell-niche interaction have just started but are expected to reveal hitherto unknown ways of signal exchange. Spermatogenesis in mammals advance our understanding of insect spermatogenesis. Mammal and insect spermatogenesis share some broad principles, but a comparison of the signaling pathways is difficult. We have intimate knowledge from Drosophila, but of almost no other insect, and we have only limited knowledge from mammals. The discovery of stem cell autotomy as part of the interaction with the niche promises new general insights into the complicated stem cell-niche interdependence.

NF-E2:a Novel Regulator of Alpha-hemoglobin Stabilizing Protein Gene Expression

Objective To investigate whether α-hemoglobin stabilizing protein (AHSP), the α-globin-specific molecular chaperone, is regulated by erythroid transcription factor NF-E2. Methods We established the stable cell line with NF-E2p45 (the larger subunit of NF-E2) short hairpin RNA to silence its expression. Western blot, real-time polymerase chain reaction, and chromatin immunoprecipitation (ChIP) analysis were performed to detect the expression of AHSP, the histone modifications at AHSP gene locus, and the binding of GATA-1 at the AHSP promoter with NF-E2p45 deficiency. ChIP was also carried out in dimethyl sulfoxide (DMSO)-induced DS19 cells and estrogen-induced G1E-ER4 cells to examine NF-E2 binding to the AHSP gene locus and its changes during cell erythroid differentiation. Finally, luciferase assay was applied in HeLa cells transfected with AHSP promoter fragments to examine AHSP promoter activity in the presence of exogenous NF-E2p45. Results We found that AHSP expression was highly dependent on NF-E2p45. NF-E2 bound to the regions across AHSP gene locus in vivo, and the transcription of AHSP was transactivated by exogenous NF-E2p45. In addition, we observed the decrease of H3K4 trimethylation and GATA-1 occupancy at the AHSP gene locus in NF-E2p45-deficient cells. Restoration of GATA-1 in G1E-ER4 cells in turn led to increased DNA binding of NF-E2p45. Conclusion NF-E2 may play an important role in AHSP gene regulation, providing new insights into the molecular mechanisms underlying the erythroid-specific expression of AHSP as well as new possibilities for β-thalassemia treatment.

Does Carica papaya leaf-extract increase the platelet count? An experimental study in a murine model

Objective:To investigate the potential role of fresh Carica papaya(C.papaya)leaf extract on haematological and biochemical parameters and toxicological changes in a murine model.Methods:In total 36 mice were used for the trial.Fresh C.papaya leaf extract[0.2 mL(2 g)/mouse]was given only to the test group(18 mice).General behavior,clinical signs and feeding patterns were recorded.Blood and tissue samples were collected at intervals.Haematological parameters including platelet,red blood cell(RBC),white blood cell<(WBC),packed cell volume(PCV),serum biochemistry including serum creatinine,serum glutamic-oxaloacetic transaminase(SCOT)and serum glutamic-pyruvic transaminase(SGPT)were determined.Organs for possible histopathological changes were examined.Results:Neither group exhibited alteration of behavior or reduction in food and water intake.Similarly,no significant changes in SCOT,SGPT and serum creatinine levels were delected in the test group.Histopathological organ changes were not observed in either group of mice except in three liver samples of the test group which had a mild focal necrosis.The platelet count(11.33±0.35)×10~5VμL(P=0.00004)and the RBC count(7.97±0.61)×10~/μL(P=0.00003)were significandy increased in the test group compared to that of the controls.However,WBC count and PCV(%)values were not changed significantly in the test group.The platelet count in the test group started to increase significantly from Day 3(3.4±0.18×10~5/μL),reaching almost a fourfold higher at Day 21(11.3×10~5/μL),while it was 3.8X10^5/μL and 5.5×10~5/μL at Day 3 and Day 21 respectively in the control.Likewise,the RBC count in the test group increased from 6×10~6/μL to 9×10~6/μL at Day 21 while it remained near constant in the control group(6×10~6μL).Conclusions:Fresh C.papaya leaf extract significandy increased the platelet and RBC counts in the test group as compared to controls.Therefore,it is very important to identify those chemicals of C.papaya leaves as it can be recommended to be used as a medication to boost thrombopoiesis and erythropoiesis in humans and in animals in which these cell lineages have been compromised.

Pharmacodynamics of CNTO 530 and Darbepoetin-α in Human TNF-α Transgenic Mice, a Murine Model of Anemia of Chronic Disease

CNTO 530 and darbepoetin-a are long lived erythropoietin receptor agonists (ERAs). Clinically, anemia of chronic disease (ACD) is associated with increased expression of tumor necrosis factor-a (TNF-a) and mice transgenic for human TNF-a develop ACD. The purpose of this investigation was to compare the effects of these agents in a murine model of ACD. Human TNF-a expressing (Tg 197) mice were administered a single subcutaneous dose of CNTO 530 or darbepoetin-a and the pharmacodynamic response in bone marrow spleen and peripheral blood evaluated. RBC life span and reticulocyte age distribution were also evaluated. CNTO 530 induced a dose responsive increase in reticulocytes, RBCs and Hgb in both wild type and Tg197 mice. Although the reticulocyte response was similar to wild types, the RBC and Hgb response to CNTO 530 in Tg197 mice was blunted. There was no statistically significant difference in RBC life span with either compound. Darbepoetin-α caused a greater peak in % dead Pro/basophilic erythroblasts, greater peak EMH in the spleen and a greater increase in reticulocyte maturation time. In contrast, despite a similar peak increase, CNTO 530 caused a more sustained response of reticulocyte, EMH, RBC and Hgb, consistent with increased exposure. In conclusion, CNTO 530 and darbepoetin-a increased RBC and hemoglobin in a murine model of ACD. Compared to darbepoetin-a, CNTO 530 had a more sustained effect, consistent with increased exposure.

Pharmacological Adjuvants to Limit Erythropoietin Stimulating Agents Exposure

Anemia in chronic kidney disease (CKD) is common, causing morbidity and mortality, and is primarily due to reduced erythropoietin (EPO) release and, to a lesser degree, shortened red cell survival. Erythropoietin Stimulating Agents like epoetin Alfa and darbepoetin alpha are used commonly to treat this form of anemia. Recent evidence suggests increased morbidity and mortality associated with higher hemoglobin in the setting of these agents use. Whether these complications are due to higher dose of erythropoietin or its resistance (i.e. inflammation), or achieving a higher hemoglobin remains unclear. Tightening restrictions on these agents has led to increase interest in the use of non-ESA adjuvants to improve erythropoiesis. This review will highlight the most promising of these agents.