Erythropoietic Response Research Articles

Antibodies to specific domains of Plasmodium falciparum erythrocyte membrane protein-1 and its relationship with protection from severe malarial anemia: A prospective study among Ghanaian children.

Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP-1) is important in malaria pathogenicity as it mediates Pf-infected erythrocytes cytoadherence to host endothelial microvasculature receptors. Naturally acquired antibodies against specific PfEMP-1 antigens may be beneficial in clinical malaria protection. This study determined antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of PfEMP-1 in children with P. falciparum malaria in Tamale, Ghana. Sixty P. falciparum-infected children, and 30 controls, aged 1-12 years were recruited for this case-control study from April to July 2023 in Northern Ghana. Participants with uncomplicated malaria had asexual P. falciparum in peripheral blood and Hb ≥ 5.0 g/dL, and severe malaria was diagnosed when participants had Hb < 5.0 g/dL in addition to asexual P. falciparum in peripheral blood. Blood cell indices were measured using hematology analyzer, and IgG antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of PfEMP-1 and pro-inflammatory cytokines were detected using enzyme-linked immunosorbent assay. Data were analyzed using SPSS version 26.0. The prevalence of PfEMP-1 IgG antibodies among P. falciparum-infected children and the uninfected group was 65.0% and 6.7%, respectively. PfEMP-1 IgG antibodies were present in 83.3% of uncomplicated malaria cases, and 46.7% in severe malaria subjects. Plasma levels of PfEMP-1 IgG antibodies were elevated in participants with uncomplicated malaria compared to those with severe malaria (p < 0.001). Hemoglobin, RBC, HCT, and platelet were significantly lower among P. falciparum-infected children without PfEMP-1 IgG antibodies than among those with the antibodies. Prevalence of anemia among children with PfEMP-1 IgG antibodies and those without the antibodies were 74.4% and 100%, respectively. The high prevalence of PfEMP-1 IgG antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains observed in participants with uncomplicated malaria, and the relationship between PfEMP-1 IgG antibodies and blood cell parameters could indicate that the antibodies may be related to effective erythropoietic response in P. falciparum malaria. Immune antibodies against DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of PfEMP-1 may suppress the deteriorating effects of PfEMP-1 antigens and provide immune protection against severe malarial anemia in children.

Apnoea as a novel method to improve exercise performance: A current state of the literature.

Acute breath-holding (apnoea) induces a spleen contraction leading to a transient increase in haemoglobin concentration. Additionally, the apnoea-induced hypoxia has been shown to lead to an increase in erythropoietin concentration up to 5h after acute breath-holding, suggesting long-term haemoglobin enhancement. Given its potential to improve haemoglobin content, an important determinant for oxygen transport, apnoea has been suggested as a novel training method to improve aerobic performance. This review aims to provide an update on the current state of the literature on this topic. Although the apnoea-induced spleen contraction appears to be effective in improving oxygen uptake kinetics, this does not seem to transfer into immediately improved aerobic performance when apnoea is integrated into a warm-up. Furthermore, only long and intense apnoea protocols in individuals who are experienced in breath-holding show increased erythropoietin and reticulocytes. So far, studies on inexperienced individuals have failed to induce acute changes in erythropoietin concentration following apnoea. As such, apnoea training protocols fail to demonstrate longitudinal changes in haemoglobin mass and aerobic performance. The low hypoxic dose, as evidenced by minor oxygen desaturation, is likely insufficient to elicit a strong erythropoietic response. Apnoea therefore does not seem to be useful for improving aerobic performance. However, variations in apnoea, such as hypoventilation training at low lung volume and repeated-sprint training in hypoxia through short end-expiratory breath-holds, have been shown to induce metabolic adaptations and improve several physical qualities. This shows promise for application of dynamic apnoea in order to improve exercise performance. HIGHLIGHTS: What is the topic of this review? Apnoea is considered as an innovative method to improve performance. This review discusses the effectiveness of apnoea (training) on performance. What advances does it highlight? Although the apnoea-induced spleen contraction and the increase in EPO observed in freedivers seem promising to improve haematological variables both acutely and on the long term, they do not improve exercise performance in an athletic population. However, performing repeated sprints on end-expiratory breath-holds seems promising to improve repeated-sprint capacity.

Haematological Profile in Patients With Acute Falciparum Malaria: A Hospital-Based Study.

Introduction Malaria is the most common parasitic disease affecting humans. Haematological alterations in malaria are expected, and these changes play a significant role in fatal complications. The present study aims to assess the clinical and haematological profile in patients with acute falciparum malaria and the significance of various haematological and coagulation alterations with the clinical severity of malaria. Methods The prospective cross-sectional study included 68 acute falciparum malaria cases. Thick and thin blood film microscopy and a rapid diagnostic kit were used to diagnose malaria. The cases were subjected to various haematological and biochemical investigations. Bone marrow aspiration samples were also collected. Using appropriate statistical methods, the findings were compared between severe and uncomplicated malaria cases. A p-value below 0.05 was considered significant. Results The participants' ages ranged from 14 to 78. Most participants (n = 51, 75%) were male and belonged to the lower income group (33, 48.5%). Significant variations in mean parasite count between severe and uncomplicated malaria cases (p-value < 0.01) were observed. The severe and uncomplicated groups showed significant differences in haemoglobin (gm/dL), haematocrit, red blood cell count, reticulocyte, serum iron, and ESR levels (p-value < 0.05). The severe malaria group had considerably reduced mean platelet counts (p-value < 0.01). Only five instances (7.3%) had an appropriate erythropoietic response after day 28. Erythroid hyperplasia with dyserythropoietic alterations was most common in patients with severe anaemia and low-grade parasitaemia. Conclusion Acute falciparum malaria is often associated with haematological alterations. Anaemia and thrombocytopenia were the most expected alterations associated with disease prognosis and mortality.

Meta-analysis identifying gut microbial biomarkers of Qinghai-Tibet Plateau populations and the functionality of microbiota-derived butyrate in high-altitude adaptation

ABSTRACT The extreme environmental conditions of a plateau seriously threaten human health. The relationship between gut microbiota and human health at high altitudes has been extensively investigated. However, no universal gut microbiota biomarkers have been identified in the plateau population, limiting research into gut microbiota and high-altitude adaptation. 668 16s rRNA samples were analyzed using meta-analysis to reduce batch effects and uncover microbiota biomarkers in the plateau population. Furthermore, the robustness of these biomarkers was validated. Mendelian randomization (MR) results indicated that Tibetan gut microbiota may mediate a reduced erythropoietic response. Functional analysis and qPCR revealed that butyrate may be a functional metabolite in high-altitude adaptation. A high-altitude rat model showed that butyrate reduced intestinal damage caused by high altitudes. According to cell experiments, butyrate may downregulate hypoxia-inducible factor-1α (HIF-1α) expression and blunt cellular responses to hypoxic stress. Our research found universally applicable biomarkers and investigated their potential roles in promoting human health at high altitudes.

A novel scenario in the therapeutic management of anemia of chronic kidney disease: placement and use of roxadustat.

Anemia is a frequent and early chronic kidney disease (CKD) complication. Its management is currently based on oral or intravenous iron supplements, erythropoiesis-stimulating agents, and red blood cell transfusions, when the benefits of transfusion outweigh the risks. Anemia in CKD patients is underdiagnosed and undertreated. Current standard of care is associated with challenges and therefore new treatment approacheshave been sought. Hypoxia-inducible factor-prolyl-hydroxylase enzyme inhibitors are a new class of orally administered drugs used to treat anemia associated with CKD. Small-molecule hypoxia-inducible factor-prolyl-hydroxylase inhibitors have a novel mechanism of action that activates the hypoxia-inducible factor (oxygen-sensing) pathway resulting in a coordinated erythropoietic response, leading to increased endogenous erythropoietin production, improved iron absorption and transport, and reduced hepcidin. Roxadustat is the first hypoxia-inducible factor-prolyl-hydroxylase inhibitor approved by the European Medicines Agency (EMA) and reimbursed in Italy by the Italian Medicines Agency (AIFA) for the treatment of adult patients with symptomatic CKD-related anemia. This authorization was based on the outcome of a globally-conducted phase 3 clinical trial program comprising eight pivotal multicenter randomized studies. In the absence of up-to-date guidelines, we performed a critical appraisal of the placement and use of roxadustat in this therapeutic context.

Regulation of haemoglobin concentration at high altitude.

Lowlanders sojourning for more than 1 day at high altitude (HA) experience a reduction in plasma volume (PV) that increases haemoglobin concentration and thus restores arterial oxygen content. If the sojourn extends over weeks, an expansion of total red cell volume (RCV) occurs and contributes to the haemoconcentration. While the reduction in PV was classically attributed to an increased diuretic fluid loss, recent studies support fluid redistribution, rather than loss, as the underlying mechanism. The fluid redistribution is presumably driven by a disappearance of proteins from the circulation and the resulting reduction in oncotic pressure exerted by the plasma, although the fate of the disappearing proteins remains unclear. The RCV expansion is the result of an accelerated erythropoietic activity secondary to enhanced renal erythropoietin release, but a contribution of other mechanisms cannot be excluded. After return from HA, intravascular volumes return to normal values and the normalisation of RCV might involve selective destruction of newly formed erythrocytes, although this explanation has been strongly challenged by recent studies. In contrast to acclimatised lowlanders, native highlanders originating from the Tibetan and the Ethiopian plateaus present with a normal or only mildly elevated haemoglobin concentration. Genetic adaptations blunting the erythropoietic response to HA exposure have been proposed as an explanation for the absence of more pronounced haemoconcentration in these populations, but new evidence also supports a contribution of a larger than expected PV. The functional significance of the relatively low haemoglobin concentration in Tibetan and Ethiopian highlanders is incompletely understood and warrants further investigation.

Abstract 11986: Erythropoietic Response After Intravenous Iron in Heart Failure With Reduced Ejection Fraction With or Without Background Treatment With Sodium-Glucose Co-Transporter 2 Inhibitors

Introduction: Intravenous (IV) iron increases hemoglobin/hematocrit and improve outcomes in patients with heart failure with reduced ejection fraction (HFrEF) and iron deficiency. Sodium glucose co-transporter 2 inhibitors (SGLT2i) also increase hemoglobin/hematocrit and improve outcomes in HF by mechanisms linked to nutrient deprivation signaling, and inflammation/oxidative stress reduction. The effect of IV iron among patients using SGLT2i has not yet been studied. Hypothesis: We hypothesize that HFrEF patients with iron deficiency treated with IV iron with a background treatment including a SGLT2i will have an increase erythropoietic response comparing to SGLT2i non users. Methods: Retrospective, single-center analysis of HFrEF patients with iron deficiency treated with IV iron using (n=60) and not using (n=60) SGLT2i, matched for age and sex. The primary outcome was the difference in absolute hemoglobin change (before vs after IV iron administration) between SGLT2i users and nonusers. The main secondary outcomes were the difference in hematocrit and iron biomarkers (total iron, ferritin and trasnferrin saturation) changes between SGLT2i users and nonusers. Results: Mean age was 73±12 years, 48% were men, with more than 65% of patients having chronic kidney disease and anemia. After adjustment for all baseline differences, SGLT2i users experienced a greater increase in hemoglobin and hematocrit compared to SGLT2i nonusers: hemoglobin +0.57 g/dL (95%CI 0.04-1.10, p=0.036) and hematocrit +1.64% (95%CI 0.18-3.11, p=0.029). No significant differences were noted for iron biomarkers or any of the secondary outcomes. Conclusion: Combined treatment with IV iron and background SGLT2i was associated with a greater increase in hemoglobin and hematocrit than IV iron without background SGLT2i. These results suggest that in HFrEF patients treated with IV iron, SGLT2i may increase the erythropoietic response.

Erythropoietin downregulates red blood cell clearance, increasing transfusion efficacy in severely anemic recipients.

Red blood cells (RBC) transfusion is used to alleviate symptoms and prevent complications in anemic patients by restoring oxygen delivery to tissues. RBC transfusion efficacy, that can be measured by a rise in hemoglobin (Hb) concentration, is influenced by donor-, product-, and recipient-related characteristics. In some studies, severe pre-transfusion anemia is associated with a greater than expected Hb increment following transfusion but the biological mechanism underpinning this relationship remains poorly understood. We conducted a prospective study in critically ill patients and quantified Hb increment following one RBC transfusion. In a murine model, we investigated the possibility that, in conjunction with the host erythropoietic response, the persistence of transfused donor RBC is improved to maintain a highest RBC biomass. We confirmed a correlation between a greater Hb increment and a deeper pre-transfusion anemia in a cohort of 17 patients. In the mouse model, Hb increment and post-transfusion recovery were increased in anemic recipients. Post-transfusion RBC recovery was improved in hypoxic mice or those receiving an erythropoiesis-stimulating agent and decreased in those treated with erythropoietin (EPO)-neutralizing antibodies, suggesting that EPO signaling is necessary to observe this effect. Irradiated recipients also showed decreased post-transfusion RBC recovery. The EPO-induced post-transfusion RBC recovery improvement was abrogated in irradiated or in macrophage-depleted recipients, but maintained in splenectomized recipients, suggesting a mechanism requiring erythroid progenitors and macrophages, but which is not spleen-specific. Our study highlights a physiological role of EPO in downregulating post-transfusion RBC clearance, contributing to maintain a vital RBC biomass to rapidly cope with hypoxemia.

Iron Status and Physical Performance in Athletes.

Iron is an important mineral in the body, essential for muscle function and oxygen transport. Adequate levels of iron in the blood are necessary for athletes, as iron-deficiency anemia can reduce physical performance. Several studies have investigated iron status and supplementation in iron-deficient athletes, and determined how physical strain can change iron balance and markers related to iron status. The question of how to influence and optimize iron status, as well as other markers that can affect iron metabolism, has been less thoroughly investigated. Therefore, the aim of this review is to take a closer look at the importance of iron values, iron markers, and factors that can change iron metabolism for physical performance and the extent to which physical performance can be influenced in a positive or negative way. A systematic search of the PubMed database was performed, with the use of « iron» or «iron deficiency» or «hemoglobin» AND «athletes» AND «athletic performance» as a strategy of the search. After the search, 11 articles were included in the review after the application of inclusion and exclusion criteria. Major findings include that iron supplementation had the best effect in athletes with the lowest iron status, and effects on physical performance were mostly achieved in those who were originally in a deficit. Iron supplementation could be beneficial for optimal erythropoietic response during altitude training, even in athletes with normal iron stores at baseline, but should be performed with caution. Alteration of the hepcidin response can affect the use of existing iron stores for erythropoiesis. Energy intake, and the amount of carbohydrates available, may have an impact on the post-exercise hepcidin response. Optimal vitamin D and B12 levels can possibly contribute to improved iron status and, hence, the avoidance of anemia.

Use of molidustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, in chronic kidney disease-associated anemia in cats.

Erythropoietic effects of molidustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor, were previously demonstrated in healthy cats. To evaluate the safety and erythropoietic effects of daily PO administration of molidustat in anemic cats with chronic kidney disease (CKD). Twenty-one client-owned CKD cats (4-17 years old) with anemia. Multicenter field study; randomized, masked, and placebo-controlled. Cats were treated PO once daily for 28 days with suspensions of control product (CP; n = 6) or 5 mg/kg of molidustat (n = 15). Hematocrit (HCT) was evaluated at weekly intervals. Individual cat treatment success was defined as a ≥4% point increase in HCT compared to baseline. Control group mean HCT remained low throughout the study (20.1%-23.4%). Mean HCT of molidustat-treated cats increased weekly, and a significant increase compared to baseline (23.6%) was first observed on Day 21 (27.3%; P < .001; 95% confidence interval [CI], 1.69-5.67). Compared to CP group, mean HCT was significantly higher on Day 21 (27.3% vs 20.1%; P < .001; 95% CI, 2.91-10.75) but not significantly higher on Day 28 (27.8% vs 23.4%; P = .06; 95% CI, -0.23 to 9.88). The number of individual treatment successes on Day 28 was higher among remaining molidustat-treated cats (7/14) compared to remaining control cats (1/5), but there was no significant difference between groups. Daily PO molidustat administration may stimulate a clinically relevant erythropoietic response in anemic cats with CKD. This HIF-PH inhibitor may be an alternative for managing anemia in cats compared to recombinant EPO treatment.

Factors Governing the Erythropoietic Response to Intravenous Iron Infusion in Patients with Chronic Kidney Disease: A Retrospective Cohort Study.

Limited knowledge exists about factors affecting parenteral iron response. A study was conducted to determine the factors influencing the erythropoietic response to parenteral iron in iron-deficient anaemic patients whose kidney function ranged from normal through all stages of chronic kidney disease (CKD) severity. This retrospective cohort study included parenteral iron recipients who did not receive erythropoiesis-stimulating agents (ESA) between 2017 and 2019. The study cohort was derived from two groups of patients: those managed by the CKD team and patients being optimised for surgery in the pre-operative clinic. Patients were categorized based on their kidney function: Patients with normal kidney function [estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2] were compared to those with CKD stages 3-5 (eGFR < 60 mL/min/1.73 m2). Patients were further stratified by the type of iron deficiency [absolute iron deficiency (AID) versus functional iron deficiency (FID)]. The key outcome was change in hemoglobin (∆Hb) between pre- and post-infusion haemoglobin (Hb) values. Parenteral iron response was assessed using propensity-score matching and multivariate linear regression. The impact of kidney impairment versus the nature of iron deficiency (AID vs. FID) in response was explored. 732 subjects (mean age 66 ± 17 years, 56% females and 87% White) were evaluated. No significant differences were observed in the time to repeat Hb among CKD stages and FID/AID patients. The Hb rise was significantly lower with lower kidney function (non-CKD and CKD1-2; 13 g/L, CKD3-5; 7 g/L; p < 0.001). When groups with different degrees of renal impairment were propensity-score matched according to whether iron deficiency was due to AID or FID, the level of CKD was found not to be relevant to Hb responses [unmatched (∆Hb) 12.1 vs. 8.7 g/L; matched (∆Hb) 12.4 vs. 12.1 g/L in non-CKD and CKD1-2 versus CKD3-5, respectively]. However, a comparison of patients with AID and FID, while controlling for the degree of CKD, indicated that patients with FID exhibited a diminished Hb response regardless of their level of kidney impairment. The nature of iron deficiency rather than the severity of CKD has a stronger impact on Hb response to intravenous iron with an attenuated response seen in functional iron deficiency irrespective of the degree of renal impairment.

Erythropoietic response after intravenous iron in patients with heart failure and reduced ejection fraction with and without background treatment with sodium-glucose cotransporter 2 inhibitors.

Intravenous (IV) iron increases haemoglobin/haematocrit and improves outcomes in patients with heart failure with reduced ejection fraction (HFrEF) and iron deficiency. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) also increase haemoglobin/haematocrit and improve outcomes in heart failure by mechanisms linked to nutrient deprivation signalling and reduction of inflammation and oxidative stress. The effect of IV iron among patients using SGLT2i has not yet been studied. The aim of this study was to evaluate the changes in haemoglobin, haematocrit, and iron biomarkers in HFrEF patients treated with IV iron with and without background SGLT2i treatment. Secondary outcomes included changes in natriuretic peptides, kidney function and heart failure-associated outcomes. Retrospective, single-centre analysis of HFrEF patients with iron deficiency treated with IV iron using (n = 60) and not using (n = 60) SGLT2i, matched for age and sex. Mean age was 73 ± 12 years, 48% were men, with more than 65% of patients having chronic kidney disease and anaemia. After adjustment for all baseline differences, SGLT2i users experienced a greater increase in haemoglobin and haematocrit compared to SGLT2i non-users: haemoglobin +0.57 g/dl (95% confidence interval [CI] 0.04-1.10, p = 0.036) and haematocrit +1.64% (95% CI 0.18-3.11, p = 0.029). No significant differences were noted for iron biomarkers or any of the secondary outcomes. Combined treatment with IV iron and background SGLT2i was associated with a greater increase in haemoglobin and haematocrit than IV iron without background SGLT2i. These results suggest that in HFrEF patients treated with IV iron, SGLT2i may increase the erythropoietic response. Further studies are needed to ascertain the potential benefit or harm of combining these two treatments in heart failure patients.

Critical role of long non-coding RNAs in excessive erythropoietic response in Monge's disease

Excessive erythrocytosis (EE) is a major hallmark of patients suffering from chronic mountain sickness (CMS, Monge’s disease) and is responsible for major morbidity and even mortality in early adulthood. We took advantage of unique populations, one living at high altitude (Peru) showing EE, while another population, at the same altitude and region, shows no evidence of EE (non-CMS). We have built an in-vitro human iPS-derived model system to study the genetic and epigenetic mechanisms related to pathology of excessive erythropoetic response in these Monge's disease patients. Through RNA-seq, we identified and validated the function of a group of long non-coding RNA (lncRNAs) that regulate erythropoiesis in Monge’s disease. Among the lncRNAs, we found that LINC02228 specifically played a critical role in erythropoiesis the CMS cells and non-CMS based on our functional assays in our in-vitro model systems. We observed that LINC02228 has a huge impact on erythriod colony production (&gt;50% reduction in colonies p&lt;0.001 with the control vs LINC02228-KD). Furthermore, we have also assessed the downstream target genes for these lncRNA (Eg. CSNK2B) and mechanism(s) of erythropoetic regulation by these lncRNAs and found an important role and mediation of erythropoetic transcriptional factor GATA1. We conclude that LINC02228 mediate erythropoesis in Monge's diseases through critical downstream effectors (CSNK2B and GATA1). NIH This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors versus erythropoiesis-stimulating agents on iron metabolism and inflammation in patients undergoing dialysis: A systematic review and meta-analysis

AimsThis study aimed to evaluate the effects of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) on iron metabolism and inflammation in dialysis-dependent chronic kidney disease (DD-CKD) patients. MethodsPubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov websites were searched for randomized controlled trials (RCTs) investigating HIF-PHIs versus ESAs for DD-CKD patients. Key findingsTwenty studies with 14,737 participants were included in the meta-analysis, which demonstrated no significant difference in the effect of transferrin saturation and ferritin between HIF-PHIs and the ESAs group (MD, 0.65; 95%CI, −0.45 to 1.75; very low certainty; SMD, −0.03; 95% CI, −0.13 to 0.07; low certainty). However, HIF-PHIs significantly increased the iron (MD, 2.30; 95% CI, 1.40 to 3.20; low certainty), total iron-binding capacity (SMD, 0.82; 95% CI, 0.66 to 0.98; low certainty), and transferrin (SMD, 0.90; 95%CI, 0.74 to 1.05; moderate certainty) levels when compared with the ESAs group. In contrast, the hepcidin level and dosage of intravenous iron were significantly decreased in the HIF-PHIs group compared with the ESAs group (MD, −15.06, 95%CI, −21.96 to −8.16; low certainty; MD, −18.07; 95% CI, −30.05 to −6.09; low certainty). The maintenance dose requirements of roxadustat were independent of baseline CRP or hsCRP levels with respect to the effect on inflammation. SignificanceHIF-PHIs promote iron utilization and reduce the use of intravenous iron therapy. Furthermore, HIF-PHIs, such as roxadustat, maintain the erythropoietic response independent of the inflammatory state. Thus, HIF-PHIs may be an alternative treatment strategy for anemia in DD-CKD patients, where ESA is hyporesponsive due to iron deficiency and inflammation.

Excessive Erythrocytosis Is Not Associated With Altered Iron Homeostasis in Men From the World's Highest City.

Excessive Erythrocytosis Is Not Associated With Altered Iron Homeostasis in Men From the World's Highest City.

Neuronal nitric oxide synthase is required for erythropoietin stimulated erythropoiesis in mice.

Introduction: Erythropoietin (EPO), produced in the kidney in a hypoxia responsive manner, is required for red blood cell production. In non-erythroid tissue, EPO increases endothelial cell production of nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) that regulates vascular tone to improve oxygen delivery. This contributes to EPO cardioprotective activity in mouse models. Nitric oxide treatment in mice shifts hematopoiesis toward the erythroid lineage, increases red blood cell production and total hemoglobin. In erythroid cells, nitric oxide can also be generated by hydroxyurea metabolism that may contribute to hydroxyurea induction of fetal hemoglobin. We find that during erythroid differentiation, EPO induces neuronal nitric oxide synthase (nNOS) and that neuronal nitric oxide synthase is required for normal erythropoietic response. Methods: Wild type (WT) mice and mice with targeted deletion of nNOS (nNOS-/-) and eNOS (eNOS-/-) were assessed for EPO stimulated erythropoietic response. Bone marrow erythropoietic activity was assessed in culture by EPO dependent erythroid colony assay and in vivo by bone marrow transplantation into recipient WT mice. Contribution of nNOS to EPO stimulated cell proliferation was assessed in EPO dependent erythroid cells and in primary human erythroid progenitor cell cultures. Results: EPO treatment increased hematocrit similarly in WT and eNOS-/- mice and showed a lower increase in hematocrit nNOS-/- mice. Erythroid colony assays from bone marrow cells were comparable in number from wild type, eNOS-/- and nNOS-/- mice at low EPO concentration. Colony number increased at high EPO concentration is seen only in cultures from bone marrow cells of wild type and eNOS-/- mice but not from nNOS-/- mice. Colony size with high EPO treatment also exhibited a marked increase in erythroid cultures from wild type and eNOS-/- mice but not from nNOS-/- mice. Bone marrow transplant from nNOS-/- mice into immunodeficient mice showed engraftment at comparable levels to WT bone marrow transplant. With EPO treatment, the increase in hematocrit was blunted in recipient mice that received with nNOS-/- donor marrow compared with recipient mice that received WT donor marrow. In erythroid cell cultures, addition of nNOS inhibitor resulted in decreased EPO dependent proliferation mediated in part by decreased EPO receptor expression, and decreased proliferation of hemin induced differentiating erythroid cells. Discussion: EPO treatment in mice and in corresponding cultures of bone marrow erythropoiesis suggest an intrinsic defect in erythropoietic response of nNOS-/- mice to high EPO stimulation. Transplantation of bone marrow from donor WT or nNOS-/- mice into recipient WT mice showed that EPO treatment post-transplant recapitulated the response of donor mice. Culture studies suggest nNOS regulation of EPO dependent erythroid cell proliferation, expression of EPO receptor and cell cycle associated genes, and AKT activation. These data provide evidence that nitric oxide modulates EPO dose dependent erythropoietic response.

The Associations between Erythropoietic Response with Inflammation Markers and Perfluorinated Chemicals in Hemodialysis Patients.

Erythropoiesis-stimulating agents (ESA) are used to treat anemia in hemodialysis (HD) patients. We investigated the role of inflammation and accumulation of environmental toxins (perfluorinated chemicals (PFCs), such as perfluorooctanoic acid and perfluorooctane sulfonate) in the erythropoietic response of HD patients who receive a fixed monthly continuous erythropoietin receptor activator (CERA) dosage. Forty-five patients underwent three successive phases of ESA treatment for two months each (phase one: 100 µg CERA once monthly; phase two: 50 µg CERA twice monthly; phase three: 100 µg CERA once monthly). Patient data were collected to determine the association of various factors with erythropoietic response (change in hematocrit). Liquid chromatography-tandem mass spectrometry was used to analyze perfluorinated chemicals. Twenty-eight patients exhibited a poor erythropoietic response that was significantly associated with: age > 80 years, initial hematocrit > 36%, glucose > 200 mg/dL, alanine aminotransferase > 21 U/L, c-reactive protein > 1 mg/dL, interleukin-6 > 10 ng/mL, lactate dehydrogenase ≤ 190 U/L, and chloride ≤ 93 mEq/L. There was also a borderline significant association between inflammation and PFCs, although PFCs failed to show any impact on ESA response. Age, glucose, chloride, liver function, and inflammation may be associated with cost-effective fixed CERA dosage administered at an increased frequency.

Determination of hematological response to iron and folic acid supplementation among the expectant mothers attending Kakamega County Referral Hospital, Kenya

Background Despite iron and folic acid supplementation program among expectant mothers while attending antenatal care clinic at Kakamega County, the rates of maternal and fetal morbidity and mortality due to anemia complications are still high. Aim First, we determined changes in hematological profiles following iron and folic acid supplementation. Second, we determined association between hematological changes with demographic and clinical characteristics in response to iron and folic acid supplementation. Patients and methods Full hemogram and reticulocyte profiles of 127 expectant mothers were determined at baseline and endpoint after 1 month of iron and folic acid supplementation. Full hemogram profiles were measured using a Maxim 3010 fully automated hematology analyzer, whereas reticulocyte profiles were examined microscopically at ×100 magnification. Demographic data were collected using pretested structured questionnaires. Results The end point measures of red blood cells, hemoglobin (Hb), hematocrit, mean cell volume, reticulocyte count, reticulocyte production index, and absolute reticulocyte number among the anemic mothers were significantly higher relative to baseline levels. Among nonanemic mothers, Hb and mean cell volume levels differed significantly between baseline and end point of the study. The change in erythropoietic response and adequate Hb response was significantly associated with adherence to iron and folic acid supplement. Conclusion Hematological profiles significantly changed especially among anemic mothers following iron and folic acid supplementation. Adherence to supplement is associated with positive erythropoietic response and adequate Hb response.

MDS-502 Supportive Care in Low-Risk Myelodysplastic Syndromes: Role of Erythropoiesis Stimulating Agents (ESAs)

Erythropoiesis stimulating agents (ESAs) are the frontline treatment in low-risk anemic MDS patients, and an employment of this therapy in the earlier stage of the disease can delay the need for RBC transfusion, hypothetically by slowing the disease course. Macrocytosis is one of the cytological hallmarks of dyserithropoiesis in MDS. An analysis of the erythropoietic response to ESAs therapy in a cohort of anemic non transfusion-dependent MDS patients, enrolled in a retrospective register, RECAMDS, subgroup of Italian register, was performed. 183 patients, treated with standard-dose ESAs, have been retrospectively analyzed. Data analysis was performed, according to IWG 2006 criteria, at the baseline, after 3 and 6 months of continuous treatment, with a subanalysis of the patients according to WHO and R-IPSS risk stratification. ESAs were started at mean Hb concentration of 9.31 g/dl, mean serum erythropoietin (EPO) concentration: 51 mU/L, after a mean time from diagnosis of 6 months (r.1-118). ORR was 83.6% (153/183); no difference among WHO and IPSS subgroups was found. 132/183 (72.1%) achieved response after 3 months of treatment, while other 21/183 (11.2%) after 6 months. 19 patients with stable disease (non-responders, according to IWG criteria), in which treatment was continued, achieved response after 9 months. In the macrocytic-responders group, 83.2% exhibited again macrocytosis after 3 months, while 16.8% become normocytic. In the normocytic-responders group, 89.8% exhibited again normocytosis, while 10.2% become macrocytic. In these patients, after 3 months, there was a contemporary worsening in neutropenia and thrombocytopenia, with transfusion-dependence, regarded as first signs of progression of disease. Non-responders were 30/183 (16.3%): in the macrocytic non-responders group 89% exhibited again macrocytosis after 3 months, while 11% become normocytic; in the normocytic group 76% exhibited again macrocytosis, while 24% become normocytic. These preliminary data can suggest that, in the majority of MDS patients responsive to ESAs, the increase of Hb concentration occurs mainly due to stimulating erythroid production in MDS clones; in the minority of patients probably it happens due to recruiting residual polyclonal erythropoiesis. It is interesting to note that stimulating effects of ESAs last even when the expression of dysplasia progresses.

Effect of hypobaric hypoxia on hematological parameters related to oxygen transport, blood volume and oxygen consumption in adolescent endurance-training athletes

Background/ObjectiveTo analyze the effect of altitude on hematological and cardiorespiratory variables in adolescent athletes participating in aerobic disciplines. Methods21 females and 89 males participated in the study. All were adolescent elite athletes engaged in endurance sports (skating, running and cycling) belonging to two groups: permanent residents in either low altitude (LA, 966 m) or moderate altitude (MA, 2640 m). Hematocrit (Hct), hemoglobin concentration ([Hb]), total hemoglobin mass (Hbt), blood, plasma and erythrocyte volumes (BV, PV and EV), VO2peak and other cardiorespiratory parameters were evaluated. ResultsSex differences were evident both in LA and HA skating practitioners, the males having higher significant values than the females in oxygen transport-related hematological parameters and VO2peak. The effect of altitude residence was also observed in Hct, [Hb], Hbt and EV with increased (14%–18%) values in the hematological parameters and higher EV (5%–24%). These results matched the significantly higher values of VO2peak measured in MA residents. However, BV and PV did not show differences between LA and MA residents in any case. Sports discipline influenced neither the hematological variables nor most of the cardiorespiratory parameters. ConclusionsLA and MA adolescent skaters showed sex differences in hematological variables. Endurance-trained male adolescent residents at MA had an increased erythropoietic response and a higher VO2peak compared to their counterparts residing and training at LA. These responses are similar in the three aerobic sports studied, indicating that the variables described are highly sensitive to hypoxia irrespective of the sports discipline.