Plasma Erythropoietin Levels Research Articles

Deficiency of lysophosphatidic acid receptor 3 decreases erythropoietin production in hypoxic mouse kidneys.

Lysophosphatidic acid (LPA) is a lipid mediator with diverse biological functions through its receptors on the cell membrane. As one of the six LPA receptors, LPA receptor 3 (LPAR3) is highly expressed in mouse kidneys, but its physiological function in the kidney has been poorly explored. Wild-type (WT) and Lpar3-/- mice were used to investigate the renal physiological function of LPAR3 under hypoxia. The expression levels of LPA receptors in the kidneys of WT mice with or without exposure to hypoxia (8% O2) were detected by RT‒qPCR. RNA sequencing analysis was performed to identify differences in gene expression profiles between the hypoxic kidneys of WT and Lpar3-/- mice. The effects of LPAR3 deficiency and treatment with the LPAR1/3 inhibitor Ki16425 or the LPAR3 selective agonist 2S-OMPT on erythropoietin (EPO) production in the kidneys of hypoxic mice were determined by RT‒qPCR and ELISAs. The mechanism of LPAR3-mediated regulation of EPO expression was further studied in vivo with mouse models and in vitro with cultured human cells. LPAR3 is the major LPA receptor in mouse kidneys, and its expression is significantly upregulated under hypoxic conditions. RNA sequencing analysis revealed that, compared with WT mice, Lpar3-/- mice presented a significant decrease in hypoxia-induced EPO expression in the kidney, together with reduced plasma EPO levels and lower hematocrit and hemoglobin levels. Hypoxic renal EPO expression in WT mice was diminished by the administration of the LPAR1/3 inhibitor Ki16425 and increased by 2S-OMPT, a selective agonist of LPAR3. Hypoxia-induced HIF-2α accumulation in mouse kidneys was impaired by LPAR3 deficiency. Further studies revealed that the PI3K/Akt pathway participated in the regulation of HIF-2α accumulation and EPO expression by LPAR3 under hypoxic conditions. Our study revealed the role of LPAR3 in promoting the HIF-2α‒EPO axis in hypoxic mouse kidneys, suggesting that the LPA receptor may serve as a novel potential pharmaceutical target to regulate renal EPO production in hypoxia-related situations, such as chronic kidney disease and altitude disease.

A Comprehensive Assessment of Prescription Patterns for Anemia Management in Pregnant Women: A Study From Anand District, India.

Introduction Pregnancy induces various physiological changes, often leading to complications. Physiological anemia of pregnancy, resulting from increased plasma volume and erythropoietin levels, poses significant health risks.Adverse outcomes associated with anemia during pregnancy include maternal and perinatal mortality, premature delivery, and low birth weight. Drug utilization research aims to promote rational drug use for improving health outcomes. The Food and Drug Administration (FDA) categorizes drugs based on teratogenic risk, providing guidance for clinicians. This study aims to analyze prescription trends and FDA risk categories for anemia in pregnant women in the Anand district. Materials and methods The study received institutional ethics approval and involved 816 pregnant women attending antenatal clinics from December 2021 to March 2023. Participants provided informed consent, and data collection included hemoglobin (Hb) levels at each trimester, categorizing participants into anemic (Hb < 11 gm/dL) and non-anemic groups. Prescribed drugs were recorded, and their essentiality was assessed using the WHO Essential Medicines List (WHO-EML) and the National List of Essential Medicines-2022 (NLEM-2022). FDA drug risk categories were utilized for assessing drug safety. Descriptive and statistical analyses were performed. Results Anemia prevalence across trimesters ranged from 62.50% to 65.93%, with an overall average of 64.42%. Iron and folic acid supplementation were significant across trimesters, with varying rates of prescription. Calcium supplementation showed fluctuations, with 100% prescription rates in later trimesters. Ascorbic acid was significantly prescribed in anemic pregnant women throughout pregnancy. Multivitamins were consistently prescribed, emphasizing their importance. The WHO-EML and NLEM-2022 highlighted essential micronutrients, while FDA categories indicated drug safety. Conclusion Anemia prevalence remained high throughout pregnancy, emphasizing the need for consistent supplementation. Prescription patterns aligned with evidence-based guidelines, focusing on iron and folic acid supplementation. Variations in calcium prescription suggest trimester-specific considerations. Prescription trends reflect a responsible approach to managing anemia during pregnancy, emphasizing prophylactic iron and folic acid therapy. The absence of high-risk medications underscores cautious prescribing practices. This study contributes valuable insights into evidence-based pharmacotherapy and maternal health care.

The drug-specific properties of hypoxia-inducible factor-prolyl hydroxylase inhibitors in mice reveal a significant contribution of the kidney compared to the liver to erythropoietin induction

AimsKidney disease often leads to anemia due to a defect in the renal production of the erythroid growth factor erythropoietin (EPO), which is produced under the positive regulation of hypoxia-inducible transcription factors (HIFs). Chemical compounds that inhibit HIF-prolyl hydroxylases (HIF-PHs), which suppress HIFs, have been developed to reactivate renal EPO production in renal anemia patients. Currently, multiple HIF-PH inhibitors, in addition to conventional recombinant EPO reagents, are used for renal anemia treatment. This study aimed to elucidate the therapeutic mechanisms and drug-specific properties of HIF-PH inhibitors. Methods and key findingsGene expression analyses and mass spectrometry revealed that HIF-PH inhibitors (daprodustat, enarodustat, molidustat, and vadadustat) alter Epo gene expression levels in the kidney and liver in a drug-specific manner, with different pharmacokinetics in the plasma and urine after oral administration to mice. The drug specificity revealed the dominant contribution of EPO induction in the kidneys rather than in the liver to plasma EPO levels after HIF-PH inhibitor administration. We also found that several HIF-PH inhibitors directly induce duodenal gene expression related to iron intake, while these drugs indirectly suppress hepatic hepcidin expression to mobilize stored iron for hemoglobin synthesis through induction of the EPO-erythroferrone axis. SignificanceRenal EPO induction is the major target of HIF-PH inhibitors for their therapeutic effects on erythropoiesis. Additionally, the drug-specific properties of HIF-PH inhibitors in EPO induction and iron metabolism have been shown in mice, providing useful information for selecting the proper HIF-PH inhibitor for each renal anemia patient.

A Genome Scale CRISPR Screen Identifies Novel Genes That Regulate Erythropoietin Production

Erythropoietin (EPO) is a plasma glycoprotein that binds bone marrow erythroid progenitors, stimulating their proliferation and differentiation. EPO is secreted into the circulation by hepatocytes and specialized kidney peritubular fibroblasts, which contribute ~20% and ~80% of the total plasma EPO level, respectively. EPO production is induced during hypoxia, due to enhanced stability of the transcription factor hypoxia-inducible factor (HIF). However, increased HIF activity results in enhanced expression of angiogenesis and oncogenesis promoting genes, raising concerns about clinical strategies that promote EPO production via increasing HIF levels. To define novel regulators of EPO production, we developed a genome-wide functional screen that provides a quantifiable and selectable readout of EPO production. In order to perform such a screen, we generated a reporter HEP3B cell line with homozygous insertion of coding sequences for p2A and eGFP at the endogenous EPO locus. This HEP3B EPO-p2A-eGFP (HEG) cell line expresses equivalent levels of EPO and eGFP proteins, both translated from the same mRNA molecule. Treatment of HEG cells with the HIF stabilizing molecule DMOG results in increased EPO expression, which is abolished by deletion of the hypoxia-responsive-element in the EPO locus. These findings demonstrate the utility of this reporter cell line to study the regulation of EPO production. To identify novel genes that regulate EPO production, we mutagenized the HEG cell line with the GeCKO-v2 CRISPR/Cas9 knock-out library, which delivers a puromycin resistance cassette, SpCas9, and a pooled collection of 123,411 single guide RNAs (sgRNAs) that include 6 independent sgRNAs targeting every human gene. Transduction was performed at a low multiplicity of infection (MOI ~0.3), so that most infected cells receive 1 sgRNA to delete 1 gene only. Puromycin selection was applied from days 1-4 post-transduction and cells were subsequently recovered for 8 days. Cells were then treated with DMOG for 24 hours or left untreated. Cells with increased (top ~10%) or decreased (bottom ~10%) eGFP fluorescence were isolated. This screen was done in biological triplicates. Genes for which sgRNAs are enriched/depleted in eGFP high versus eGFP low DMOG-treated cells likely impact EPO expression independently of the HIF pathway. In contrast, genes for which sgRNAs are enriched/depleted in eGFP high versus eGFP low untreated cells may impact EPO expression in either a HIF dependent or independent manner. As expected, sgRNAs targeting VHL were found to be among the most significantly enriched sgRNAs in eGFP-high versus eGFP-low cells under no treatment conditions. Also as anticipated, sgRNAs targeting genes known to promote EPO production ( HNF4A, WT1, RXRA, and CREBBP) were enriched in eGFP-low versus eGFP-high cells under either DMOG-treated or untreated conditions. To refine our findings, we generated a custom library targeting the top 1,200 candidate regulators of EPO production nominated by the genome-scale screen. Using this library, we performed a secondary CRISPR screen (in biological triplicates) as above. Owning to the 10-fold smaller size of the custom library, the secondary screen was performed with average coverage of &amp;gt;150x throughout the entire screen (including the sorted cell populations). Indeed, the statistical confidence obtained with the secondary screen was superior than that achieved in the genome scale screen. Using a false discovery rate (FDR) cutoff of 1%, gene-level analysis identified 100 and 79 candidate genes whose targeting was associated with increased or decreased EPO production respectively, under either untreated or DMOG-treated conditions. A high degree of concordance was observed for regulators of EPO expression between both screens, performed with and without DMOG treatment. To identify genes that regulate EPO production independent of HIF, we evaluated several of the top genes for which sgRNAs were enriched in eGFP high vs. eGFP low cells treated with DMOG. Using 3 independent sgRNAs targeting each of these candidates, we found 2 genes ( ZNF574 and RBM18), that when deleted, result in increased EPO mRNA, even following DMOG treatment. Additional validation experiments as well as studies aimed to define the role of these 2 genes in the regulation of EPO production are ongoing.

A Combined Biomarker That Includes Plasma Fibroblast Growth Factor 23, Erythropoietin, and Klotho Predicts Short- and Long-Term Morbimortality and Development of Chronic Kidney Disease in Critical Care Patients with Sepsis: A Prospective Cohort.

Acute Kidney Injury (AKI) is a frequent complication in intensive care unit (ICU) patients that increases mortality and chronic kidney disease (CKD) development. AKI is associated with elevated plasma fibroblast growth factor 23 (FGF23), which can be modulated by erythropoietin (EPO) and Klotho. We aimed to evaluate whether a combined biomarker that includes these molecules predicted short-/long-term outcomes. We performed a prospective cohort of ICU patients with sepsis and previously normal renal function. They were followed during their inpatient stay and for one year after admission. We measured plasma FGF23, EPO, and Klotho levels at admission and calculated a combined biomarker (FEK). A total of 164 patients were recruited. Of these, 50 (30.5%) had AKI at admission, and 55 (33.5%) developed AKI within 48 h. Patients with AKI at admission and those who developed AKI within 48 h had 12- and 5-fold higher FEK values than non-AKI patients, respectively. Additionally, patients with higher FEK values had increased 1-year mortality (41.9% vs. 18.6%, p = 0.003) and CKD progression (26.2% vs. 8.3%, p = 0.023). Our data suggest that the FEK indicator predicts the risk of AKI, short-/long-term mortality, and CKD progression in ICU patients with sepsis. This new indicator can improve clinical outcome prediction and guide early therapeutic strategies.

The Relationship between Plasma Erythropoietin Levels and Symptoms of Attention Deficit Hyperactivity Disorder

IntroductionThere are animal models associating dopamine dysfunction with behavioral impairments that model attention deficit hyperactivity disorder (ADHD). Erythropoietin (EPO) has trophic effects on dopaminergic neurons.ObjectivesThe aim of this study was to examine the Erythropoietin (EPO) plasma levels and determine whether there was any correlation between plasma EPO levels and clinical characteristics of Attention-Deficit/Hyperactivity Disorder(ADHD).MethodsPlasma EPO levels were measured in 78 drug naïve children with ADHD and in 81 healthy children. The severity of ADHD symptoms was determined by scores on the Korean ADHD Rating Scale (K-ARS) in children and healthy controls.ResultsThe ADHD group consisted of 64 boys and 14 girls, and the healthy control group of 31 boys and 50 girls. The median plasma EPO levels in ADHD children was 12.9 mIU/mL, whereas it was 12.0 mIU/mL in the healthy controls. This difference was not statistically significant. Participants in the highest tertiles of plasma EPO had a 1.49 times higher risk of ADHD than those in the lowest tertile, and those in the second highest tertile had a 2.39 times higher risk of ADHD than those in the lowest tertile. Plasma EPO levels correlated positively with some K-ARS scores, including hyperactivity-impulsivity score and total score. The significant difference in hyperactivity-impulsivity score comparing participants in the second highest with those in the lowest tertile. total K-ARS score was significantly higher in the second highest tertile of plasma EPO compared to those in the lowest tertile.ConclusionsThese findings suggest that plasma EPO levels were related to some ADHD symptoms, which could be used in the monitoring of the disorder. Further studies are required to clearly understand the source and role of EPO in ADHD.Disclosure of InterestNone Declared

RESEARCH ON PLASMA ERYTHROPOIETIN CONCENTRATION IN TYPE 2 DIABETIC PATIENTS WITH KIDNEY INJURY

Objectives: To investigate plasma erythropoietin (EPO) concentration and its relationship with some characteristics in type 2 diabetic patients (T2DM) with chronic kidney injury (CKI). Subjects and methods: A cross-sectional descriptive study on 219 subjects, including 129 patients with type 2 diabetes with chronic kidney injury, 51 patients with diabetes without CKI as a disease control group, and 39 healthy people as a normal control group. All subjects had their plasma EPO levels quantified by ELISA. Results: The median EPO concentration of the research group was 35.83 (21.55 - 56.34) UI/L, lower than the disease control group, which was 44.72 (37.25 - 63.90) UI/L, and lower than the normal control group, which was 113.31 (30.55 - 378.42) UI/L, p &lt; 0.001. The rate of EPO reduction in the study group was 41.9%. EPO concentration was positively correlated with GFR, r = 0.242, p &lt; 0.01. Creatinine is an independent factor associated with reduced EPO, p &lt; 0.05. Conclusion: The rate of EPO reduction in the type 2 DM group with CKI was 41.9%. Decreases in EPO levels are common in KI patients with type 2 diabetes and are associated with decreased GFR.

Abstract 104: Cytochrome B5 Reductase 3 Regulates The Erythropoietin Response To Ischemic Stroke In A Mouse Model Of Chronic Anemia And Oxidative Stress

Introduction: Cytochrome b5 reductase 3 (Cyb5R3) is a heme iron reductase that reverses oxidized soluble guanylate cyclase (sGC) heme iron (Fe 3+ Fe 2+ ) to preserve nitric oxide signaling. Under oxidative stress, such as occurs with sickle cell disease (SCD) and ischemic stroke, Cyb5R3 redox signaling provides resilience against tissue damage. A loss-of-function (roughly 50%) Cyb5R3 missense variant (T117S) occurs with high frequency (0.23 minor allele) in persons of African ancestry, who also suffer a greater burden of sickle cell anemia and ischemic stroke than other races. We hypothesized that Cyb5R3 regulates the erythropoietin response to ischemic stroke in a mouse model of SCD. Methods: Age-matched male SCD mice with wild-type Cyb5R3 (SS WT ) or T117S Cyb5R3 (SS T117S ) underwent middle cerebral artery occlusion (55 min) and reperfusion (48 hr). Blood was sampled at baseline and 48h reperfusion for hematology measurements. Brains were stained with 2,3,5-triphenyltetrazolium chloride to quantify infarct volume. Erythropoietin (EPO), heme oxygenase 1 (HMOX1) and sGC were assayed by Western blot. Results: We found brain infarct volume to be greater in SS T117S vs SS WT (63 vs 27 cm 3 , respectively; P=0.003). Red cells, hematocrit and hemoglobin decreased in SS T117S post-stroke, which was opposite to SS WT (red cells: -13% vs 13%, P=0.01; hematocrit: -20% vs 0%, P=0.03; hemoglobin: -18% vs 3%, P=0.02, respectively). In the absence of stroke (age-matched controls), SS WT had elevated HMOX1 protein compared to SS T117S , which normalized in post-stroke SS WT but was unchanged in post-stroke SS T117S . Kidney and plasma EPO levels significantly increased in SS WT post-stroke, but not in SS T117S . In vitro studies using HEK293 cells showed EPO and HMOX1 decrease with Cyb5R3 knockdown by siRNA. Conclusion: Our findings suggest a modifying role for Cyb5R3 in brain-kidney crosstalk during ischemic stroke, wherein loss of T117S Cyb5R3 activity negatively impacts renal and plasma EPO levels and resilience against infarct of ischemic brain tissue. The Cyb5R3 axis on which the brain-kidney-blood response to stroke in SCD turns represents a novel target for precision medicine approaches to managing stroke risk and pathology in SCD carriers of the T117S variant.

Effects of green tea extract treatment on erythropoiesis and iron parameters in iron-overloaded β-thalassemic mice.

β-Thalassemia is characterized by ineffective erythropoiesis leading to chronic anemia. Thus, increased iron absorption from the duodenum and via blood transfusions is required to maintain normal blood hemoglobin (Hb) levels and iron chelators in the removal of excessive iron. Certain agents are also needed for the improvement of stress erythropoiesis and iron dysregulation. Green tea extract (GTE), which is rich in epigallocatechin-3-gallate (EGCG), is known to possess radical scavenging and iron-chelating activities. We aimed to assess the effects of green tea extract on erythroid regulators, iron mobilization and anti-lipid peroxidation in the liver, spleen, and kidneys of iron-loaded β-globin gene knockout thalassemic (BKO) mice. Our results indicate that treatments of green tea extract and/or deferiprone (DFP) diminished levels of plasma erythropoietin (EPO) and erythroferrone (ERFE), and consistently suppressed kidney Epo and spleen Erfe mRNA expressions (p < .05) in iron- loaded BKO mice when compared with untreated mice. Coincidently, the treatments decreased plasma ferritin (Ft) levels, iron content levels in the liver (p < .05), spleen (p < .05), and kidney tissues of iron-loaded BKO mice. Furthermore, lipid-peroxidation products in the tissues and plasma were also decreased when compared with untreated mice. This is the first evidence of the orchestral role of green tea extract abundant with epigallocatechin-3-gallate in improving ineffective erythropoiesis, iron dysregulation and oxidative stress in iron-overloaded β-thalassemic mice.

Amyloidogenic amylin deposits on red blood cells of stroke patients

AbstractBackgroundAmylin, a 37‐residue amyloidogenic peptide, is co‐secreted with insulin by pancreatic beta‐cells (Verma et al. 2020). Vascular deposition of amylin has been noted in patients with diabetes and neurocognitive disorders (Ly et al., 2017) Emergent large vessel occlusions (ELVOs) result in severe ischemic strokes without appropriate treatment. Growth factors, including erythropoietin (EPO), are involved in post‐stroke recovery as a potential neuroprotectant target, inhibiting apoptosis and decreasing inflammation (Jerndal et al., 2010). Here, amylin accumulation in plasma, red blood cells (RBCs), and ELVOs (where available) and plasma EPO levels were compared between stroke and control patients. Due to amylin’s amyloidogenic propensity, we hypothesized that there would be an association between amylin uptake and stroke incidence.MethodA prospective registry (Blood and Clot Thrombectomy Registry and Collaboration; BACTRAC) was developed to analyze blood and thrombus directly in patients presenting with an ELVO. Total protein concentration and amylin concentrations of clot lysates, plasma, and RBC lysates were obtained via bicinchoninic acid assay (BCA) and competitive enzyme‐linked immunosorbent assay (ELISA), respectively. Plasma EPO concentrations were obtained via ELISA. An amylin uptake coefficient (the level of amylin in RBC lysates divided by the sum of amylin present in RBC lysates and plasma) was calculated to determine the degree to which circulating amylin is depositing on RBCs.ResultDue to a significant difference between control and stroke RBCs (p = 0.0012, Figure 1) in total protein concentration, all downstream analyses were normalized to respective protein concentrations. A significant difference in amylin uptake by RBCs between stroke and control patients is shown in Figure 2 (p = 0.0073). An uptake coefficient greater than 0.50 indicates uptake of amylin by RBCs. Finally, a significant difference in plasma EPO concentration was observed between stroke and control (p = 0.0017; Figure 3).ConclusionConsistent with our hypotheses, the present data indicates that amylin uptake by RBCs is significantly increased in stroke patients than in control patients. However, both groups show evidence of accumulation, as indicated by uptake coefficients greater than 0.50. Further, levels of erythropoietin are significantly increased in stroke patients. Further investigation into whether amylin may be thrombogenic is warranted.

Plasma Level of Apelin as a Promising Factor for Retinopathy of Prematurity

Introduction: The aim of this study was to investigate the relevance of plasma levels of apelin and other risk factors in infants with retinopathy of prematurity (ROP). Methods: This was a single-center cross-sectional study. Fifty preterm infants with ROP and 50 preterm infants without ROP were enrolled. The analysis included evaluation of gestational age (GA), birth weight (BW), and measurement of plasma concentrations of apelin, vascular endothelial growth factor (VEGF), erythropoietin (EPO), and insulin-like growth factor (IGF-1) using enzyme-linked immunosorbent assay. Results: The mean BW and GA of babies with ROP were considerably lower than those without ROP (p < 0.001, p = 0.003, respectively). Plasma levels of VEGF, EPO, and IGF-1 were all lower in babies with ROP (all p < 0.001), while plasma apelin levels were greater (p < 0.001). We compared the sensitivity and selected the best cut-offs while keeping the specificity constant (80.0%). Among all the criteria, plasma apelin levels had the best sensitivity (72%), with the cut-off of 21.08 pg/mL. Multivariable logistic regression analyses showed that the plasma level of apelin was the only parameter associated with ROP (p = 0.02, OR = 16, 95% CI: 1.54–166.53). The area under the curve of the multivariable regression model that comprised GA, BW alone was 0.67, while that of the model that included apelin was 0.90. Conclusions: Plasma apelin level demonstrated good sensitivity and specificity with regard to the association of ROP; the inclusion of apelin may be a promising factor to include in screening criteria.

Synthesis and biological evaluation of (4-hydroxy-2-(substitued sulfonamido)pyrimidine-5-carbonyl)glycines as oral erythropoietin secretagogues

Erythropoietin (EPO) is the predominant regulating factor in erythropoiesis. Herein we describe the identification of (4-hydroxy-2-(substitued sulfonamido)pyrimidine-5-carbonyl) glycine-based oral EPO secretagogues. Most of these compounds obviously increased the EPO level in Hep3B cells by stabilizing the hypoxia-inducible factor-α (HIF-α). Furthermore, their potential inhibitory activities against HIF prolyl hydroxylase domain (PHD) revealed their function as PHD inhibitors in PHD-HIF pathway. Compound 6i, with a biphenyl substituent on the sulfonamido group, particularly increased plasma EPO level in mice and could serve as a candidate of EPO stimulating agent for anemia treatment.

Endocytosis of the thrombopoietin receptor Mpl regulates megakaryocyte and erythroid maturation in mice.

Dnm2fl/fl Pf4-Cre (Dnm2Plt–/– ) mice lacking the endocytic GTPase dynamin 2 (DNM2) in platelets and megakaryocytes (MKs) develop hallmarks of myelofibrosis. At the cellular level, the tyrosine kinase JAK2 is constitutively active but decreased in expression in Dnm2Plt–/– platelets. Additionally, Dnm2Plt–/– platelets cannot endocytose the thrombopoietin (TPO) receptor Mpl, leading to elevated circulating TPO levels. Here, we assessed whether the hyperproliferative phenotype of Dnm2Plt–/– mice was due to JAK2 constitutive activation or to elevated circulating TPO levels. In unstimulated Dnm2Plt–/– platelets, STAT3 and, to a lower extent, STAT5 were phosphorylated, but their phosphorylation was slowed and diminished upon TPO stimulation. We further crossed Dnm2Plt–/– mice in the Mpl–/– background to generate Mpl–/–Dnm2Plt–/– mice lacking Mpl ubiquitously and DNM2 in platelets and MKs. Mpl–/– Dnm2Plt–/– platelets had severely reduced JAK2 and STAT3 but normal STAT5 expression. Mpl–/– Dnm2Plt–/– mice had severely reduced bone marrow MK and hematopoietic stem and progenitor cell numbers. Additionally, Mpl–/– Dnm2Plt–/– mice had severe erythroblast (EB) maturation defects, decreased expression of hemoglobin and heme homeostasis genes and increased expression of ribosome biogenesis and protein translation genes in spleen EBs, and developed anemia with grossly elevated plasma erythropoietin (EPO) levels, leading to early fatality by postnatal day 25. Mpl–/– Dnm2Plt+/+ mice had impaired EB development at three weeks of age, which normalized with adulthood. Together, the data shows that DNM2-dependent Mpl-mediated endocytosis in platelets and MKs is required for steady-state hematopoiesis and provides novel insights into a developmentally controlled role for Mpl in normal erythropoiesis, regulating hemoglobin and heme production.

Activation of Sympathetic Nervous System Contributes to Erthroprotein Gene Upregulation by Hypobaric Hypoxia

Hypobaric hypoxia (HH) experienced at high altitude initiates a series of physiological adaptations to maintain homeostasis. One such adaptation is the activation of the Epo gene which encodes the glycoprotein hormone erythropoietin (EPO). Increased circulating EPO levels defend against HH by facilitating blood O2 transport through increasing red blood cell production. HH also increases blood pressure (BP) through activation of the sympathetic nervous system and the ensuing elevation of circulating catecholamine levels. The present study examined the role of sympathetic nerve activation in HH‐evoked Epo gene activation and elevated circulating levels of EPO. Studies were performed on adult, male wild‐type (WT) mice treated with 18 hours of HH (0.4 atmospheres), simulating low O2 condition experienced at high altitude. Our results showed increased renal Epo gene abundance and elevated plasma EPO levels. Remarkably, these responses were either markedly attenuated or absent in mice with selective ablation of adrenal medulla as well as after treatment with propranolol, a non‐selective beta‐adrenergic receptor blocker. Moreover, infusion of epinephrine alone activated renal Epo gene and elevated plasma EPO levels. These results suggest that sympathetic nerve activation and the ensuing increase in plasma epinephrine contribute to Epo gene activation by HH.

Monthly Continuous Erythropoietin Receptor Activator Versus Weekly Epoetin-Beta, Similar Hemoglobinization but Different Anisocytosis Degree in Hemodialysis Patients: A Randomized Controlled Trial.

BackgroundThe monthly continuous erythropoietin receptor activator (CERA) utilization maintains stable hemoglobin (Hb) after conversion from weekly epoetin-β (EB); however, how the different pharmacologic properties affect the red blood cell (RBC) size determined by RBC distribution width (RDW) has not been evaluated yet. We assess the potential differences in iron metabolism, plasma erythropoietin (EPO), hepcidin, and soluble α-Klotho (α-Klotho) levels as an emergent hematopoiesis factor.MethodsThirty-seven chronic hemodialysis patients were included from January 2010 to November 2011 and randomized (1:1) to continue with EB or to convert to monthly CERA. Primary outcome was the mean change in Hb between groups at months 0, 3 and 6, and the percentage of patients who maintained stable Hb (Hb ± 1 g/dL from baseline level to month 6). Secondary outcomes were the influence on the erythropoietic process and iron metabolism markers. Thirty-one patients completed the study (CERA: n = 15, EB: n = 16).ResultsThe mean (95% confidence interval (CI)) Hb difference between groups was 0.28 g/dL (-0.36 to 0.93). There was no difference between the percentages of patients with stable Hb levels. In the CERA group RDW values increased progressively (interaction erythropoietin-stimulating agent (ESA) type and time on RDW values, F (1.57, 45.60) = 17.17, P < 0.01, partial η2 = 0.37) and the mean corpuscular volume changed at the different time points, (F (2, 28) = 29.12, P = 0.03, partial η2 = 0.23). During the evaluation period, in the CERA group, EPO was higher, and hepcidin and ferritin decreased significantly. α-Klotho decreased in both groups and correlated negatively with the changes on the RDW and positively with transferrin and serum iron. The number of serious adverse events was higher at the CERA group.ConclusionsMonthly CERA maintained Hb concentrations; however, it showed a significant effect on RDW, probably due to its impact on the EPO and hepcidin levels. α-Klotho decreased significantly in both groups, and its changes correlated with the changes in iron metabolism. Whether the RDW evolution was associated with the serious adverse events (SAEs) is a feasible hypothesis that needs to be confirmed in large studies.

Discovery of a Potent and Orally Bioavailable Hypoxia-Inducible Factor 2α (HIF-2α) Agonist and Its Synergistic Therapy with Prolyl Hydroxylase Inhibitors for the Treatment of Renal Anemia.

Activation of hypoxia-inducible factor 2 (HIF-2) has emerged as a potent renal anemia treatment strategy. Here, the benzisothiazole derivative 26 was discovered as a novel HIF-2α agonist, which first demonstrated nanomolar activity (EC50 = 490 nM, Emax = 349.2%) in the luciferase reporter gene assay. Molecular dynamics simulations indicated that 26 could allosterically enhance HIF-2 dimerization. Furthermore, compound 26 had a good pharmacokinetic profile (the oral bioavailability in rats was 41.38%) and an in vivo safety profile (the LD50 in mice was greater than 708 mg·kg-1). In the in vivo efficacy assays, the combination of 26 and the prolyl hydroxylase inhibitor, AKB-6548, was confirmed for the first time to synergistically increase the plasma erythropoietin level in mice (from 260 to 2296 pg·mL-1) and alleviate zebrafish anemia induced by doxorubicin. These results provide new insights for HIF-2α agonists and the treatment of renal anemia.

Epidemiologic and Genetic Associations of Erythropoietin With Blood Pressure, Hypertension, and Coronary Artery Disease.

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The Relationship between Plasma Erythropoietin Levels and Symptoms of Attention Deficit Hyperactivity Disorder.

ObjectiveThere are animal models associating dopamine dysfunction with behavioral impairments that model attention deficit hyperactivity disorder (ADHD). Erythropoietin (EPO) has trophic effects on dopaminergic neurons. The aim of this study was to examine the EPO plasma levels and determine whether there was any correlation between plasma EPO levels and clinical characteristics of ADHD.MethodsPlasma EPO levels were measured in 78 drug-naïve children with ADHD and in 81 healthy children. The severity of ADHD symptoms was determined by scores on the Korean ADHD Rating Scale (K-ARS) in ADHD children and healthy controls.ResultsThe difference between median plasma EPO levels in ADHD children and in healthy controls was not statistically significant. Adjusting for age and sex, a linear regression analysis showed that inattention score was significantly higher in the second highest tertile of plasma EPO compared to those in the lowest tertile. Hyperactivity-impulsivity score was significantly higher in the highest tertile of plasma EPO compared to those in the lowest tertile. Moreover, total K-ARS scores were significantly higher in the second highest tertile of plasma EPO compared to those in the lowest tertile.ConclusionThese findings suggest that plasma EPO levels were related to some ADHD symptoms, which could be used in the monitoring of the disorder.

Variable alterations in plasma erythropoietin and brain-derived neurotrophic factor levels in patients with major depressive disorder with and without a history of suicide attempt

It is hypothesized that major depression disorder (MDD) is associated with impaired neuronal plasticity, and that antidepressant treatments restore neuroplasticity. Brain-derived neurotrophic factor (BDNF) and erythropoietin (Epo) show neurotrophic and neuroprotective effects. We evaluated plasma Epo and BDNF levels in 50 MDD inpatients before treatment and in 50 healthy controls. The MDD inpatients consisted of 20 MDD patients without and 30 MDD patients with a recent suicide attempt. The plasma Epo level was significantly higher in nonsuicidal and suicidal MDD patients than in healthy controls (p ≤ 0.001), while the plasma BDNF level was significantly lower in suicidal MDD than in nonsuicidal MDD patients and healthy controls (p ≤ 0.001). When classifying study participants into low-Epo and high-Epo and low-BDNF and high-BDNF subgroups based on the cutoff of Epo or BDNF calculated using receiver operating characteristics (ROC) curve analysis, logistic regression analysis revealed that high-Epo and low-BDNF status correlated with a respective significant odds ratio of 7.367 (p = 0.015) and 33.123 (p ≤ 0.001) for suicidal MDD. In conclusion, plasma BDNF level was decreased in untreated MDD patients, which was presumed to be a dysfunctional effect of the onset of MDD. However, an increase in plasma Epo was observed in MDD in connection with a recent suicide attempt, indicating that this triggers hypoxic stress to induce a compensatory increase in Epo.

Plasma erythropoietin level and heart failure in patients undergoing peritoneal dialysis: a cross-sectional study

BackgroundRenal anemia is the important complication in patients undergoing peritoneal dialysis (PD), and heart failure (HF) is the important complication in patients on dialysis. Decreasing endogenous erythropoietin (EPO) in patients with chronic kidney disease is a major cause of renal anemia. On the other hand, high levels of EPO have been associated with the prognosis of patients with chronic HF. The association between plasma EPO and HF in patients on PD remains unclear. This study was designed to test our hypothesis that the plasma EPO level in patients on PD was associated with the markers of HF.MethodsWe investigated 39 patients undergoing PD at our hospital. We measured plasma EPO before erythropoiesis-stimulating agent (ESA) administration at the regular outpatient visits and then at 2 weeks after the final dose of ESA was administered and investigated the clinical factors. We estimated the correlations between the plasma EPO and the other parameters, and constructed univariate and multivariate logistic regression models for the risk for HF to estimate the effectiveness of plasma EPO and other factors on HF treatment in patients undergoing PD.ResultsThe plasma EPO concentration was positively correlated with the ESA dose and negatively correlated with serum ferrum, transferrin saturation, and body mass index and showed no correlation with other factors, such as the New York Heart Association (NYHA) classification and ferritin level. In univariate analysis, the factors significantly associated with HF risk were N-terminal pro-brain natriuretic peptide (NT-pro BNP), cardiothoracic ratio (CTR), serum creatinine (Cr), serum beta 2 microglobulin, dialysate dose, left ventricular mass index, left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and weekly Kt/V. We performed a multivariate analysis with NT-pro BNP, Cr, and CTR, and all three factors were significant in the analysis.ConclusionThe plasma EPO level in patients undergoing PD was positively correlated with the monthly ESA dose and was not significant as a marker of HF, as judged with the NYHA classification. Therefore, the plasma EPO level may not be a useful marker for HF in patients undergoing PD.