losartan-potassium and Anemia--Sickle-Cell

The past five decades have seen an improvement in the mortality and morbidity of sickle cell disease (SCD) because of prophylaxis against infectious complications, improved and expanded red cell transfusions, implementation of hydroxyurea therapy, and advances in supportive care. Now that the majority of patients in the western hemisphere reaches adulthood, end organ diseases are frequent, which include vasculopathic complications such as chronic leg ulcers. The management of patients with leg ulcers requires the hematologist to lead a team of health care professionals, and investigates the presence of associated, but potentially still occult signs of vasculopathy, such as pulmonary hypertension, renal disease, priapism and retinopathy. These complications may be asynchronous, and long term careful screening is indicated, in order to ensure early diagnosis and intervention. It is crucial to address both the immediate consequences of pain, infection and disability, and long term effects on quality of life, employment and stigma associated with chronic ulceration. Recent insights into their pathophysiology may have practical implications. We propose a holistic approach to the management of patients' physical and emotional problems and mechanisms of ulcers formation and delayed healing. An overview of topical and systemic therapies for chronic ulcers is given, with the understanding that wound care therapy is best left to the wound specialists, medical and surgical, with whom the hematologist must keep an open line of communication. In the absence of evidence-based guidelines, our opinion is based on both a critical review of the literature and our personal clinical and research experience.

Topics: Anemia, Sickle Cell; Drug Therapy, Combination; Erythropoietin; Humans; Hydroxyurea; Leg Ulcer; Recurrence; Treatment Outcome; Wound Healing

Blood erythropoietin (EPO) increases primarily to hypoxia. In sickle cell anaemia (homozygous HBBE6V; HbSS), plasma EPO is elevated due to hemolytic anaemia-related hypoxia. Hydroxyurea treatment reduces haemolysis and anaemia by increasing foetal haemoglobin, which leads to lower hypoxic transcriptional responses in blood mononuclear cells but paradoxically further increases EPO. To investigate this apparent hypoxia-independent EPO regulation, we assessed two sickle cell disease (SCD) cohorts for genetic associations with plasma EPO, by prioritizing 237,079 quantitative trait loci for expression level and/or transcript isoform variations of 12,727 genes derived from SCD blood mononuclear cells. We found an association between the T allele of SNP rs60684937 and increased plasma EPO (n = 567, combined P = 5.5 × 10 − 8 adjusted for haemoglobin and hydroxyurea) and validated it in independent SCD patients (n = 183, P = 0.018). The T allele of rs60684937 was associated with a relatively increased expression of a non-coding transcript of PRKAR1A (cAMP-dependent protein kinase type I-alpha regulatory subunit) in 58 SCD patients (P = 7.9 × 10 − 7) and 58 HapMap Yoruba samples (P = 0.0011). In conclusion, we demonstrate that plasma EPO elevation with hydroxyurea in SCD is independent of hypoxic responses and that genetic variation at SNP rs60684937 may contribute to EPO regulation through a cAMP-dependent protein kinase A pathway.

Topics: Anemia, Sickle Cell; Antisickling Agents; Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; Erythropoietin; Female; Gene Expression Profiling; Gene Expression Regulation; Genetic Association Studies; Humans; Hydroxyurea; Leukocytes, Mononuclear; Male; Pharmacogenomic Variants; Polymorphism, Single Nucleotide

Topics: Anemia, Sickle Cell; Biopsy; Complementary Therapies; Diagnosis, Differential; Erythropoietin; Hemochromatosis; Hepatitis C, Chronic; Humans; Iron; Kidney Transplantation; Liver; Metabolic Syndrome; Phlebotomy; Polycythemia; Polycythemia Vera; Porphyria Cutanea Tarda; Postoperative Complications

This review presents the indications and contraindications (pros and cons) for the potential use of erythropoietin (Epo) as a treatment in β-thalassemia and sickle cell anemia (SCA). Its high cost and route of administration (by injection) are obvious obstacles, especially in underdeveloped countries, where thalassemia is prevalent. We believe that from the data summarized in this review, the time has come to define, by studying in vitro and in vivo models, as well as by controlled clinical trials, the rationale for treating patients with various forms of thalassemia and SCA with Epo alone or in combination with other medications.

Topics: Anemia, Sickle Cell; beta-Thalassemia; Drug Therapy, Combination; Erythropoietin; Hemoglobinopathies; Humans; Treatment Outcome

In the last decade, the care of patients with sickle cell disease (SCD) has undergone important advances with better understanding of disease pathophysiology and improvement in standards of care, especially among paediatric patients. Although many new drugs are currently being investigated and are at different stages of development, the pace of drug discovery and utilization has been slow and suboptimal. Hydroxycarbamide (hydroxyurea) has been investigated and utilized for at least two decades. Hydroxycarbamide's efficacy has been demonstrated, albeit with different levels of evidence, in paediatric and adult populations, and yet clinician and patient acceptance and use have been far from ideal. In this review we discuss the current usage of hydroxycarbamide and its possible future indications in SCD, as well as the use of new compounds that have very different mechanisms of action, which may prove safe and efficacious when used alone or in combination in patients with SCD.

Topics: Anemia, Sickle Cell; Antisickling Agents; Clinical Trials as Topic; Erythropoietin; Humans; Ion Channels; Vasodilator Agents

For the majority of children with beta- hemoglobinopathies and -thalassemias who do not have a transplant donor, survival is shortened and morbidity is high. Hydroxyurea, EPO preparations, sodium phenylbutyrate, arginine butyrate, and 5-azacytidine/decitabine have shown efficacy in approximately 40% to 70% of sickle cell and beta-thalassemia patients. Many responses, although significant, were not completely ameliorating of symptoms or pathology, and trials of new agents with dual actions, or drug combinations, are needed. Ideally, limiting chemotherapeutic exposure is desirable for long-term treatment of children, and an oral therapeutic at tolerable doses is necessary for practical use. A new oral therapeutic candidate that induces fetal hemoglobin production and also stimulates erythropoiesis is entering clinical evaluation. Use of agents that should have additive or synergistic effects in combination, such as EPO and hydroxyurea or a short-chain fatty acid derivative (SCFAD), offer better therapeutic potential than hydroxyurea alone. Childhood is an optimal time to introduce such therapies, particularly the non-mutagenic SCFADs, while the erythroid marrow reserve is preserved and before organ damage has become widespread. A challenge for successful application of these therapies is to define patient subsets that are most likely to respond to a particular agent, or which require combination therapies, and to develop optimal dose regimens in thalassemias with rapid erythroid apoptosis. Development of this therapeutic avenue will require close collaboration among treating and academic physicians, families and patients, funding agencies, and researchers.

Topics: Anemia, Sickle Cell; Antisickling Agents; beta-Thalassemia; Erythropoiesis; Erythropoietin; Fatty Acids; Hemoglobinopathies; Humans; Hydroxyurea; Trans-Activators

Recent advances in the pathophysiology, clinical investigations, and management of sickle hemoglobinopathies enables all physicians to better manage these disease states and their sequelae. Patients with sickle cell disease SCD are living longer and are thus more likely to contract unrelated diseases that require surgery and anesthesia. Patients with SCD continue to be a challenge to all branches of medicine particularly in obstetrics, surgery and anesthesia; however, the armamentarium of new knowledge and practice places a different perspective on the care of this old disease. In general, the literature to date suggests that neither prophylactic transfusion of pregnant sicklers nor the selection of an anesthetic in labor have a major impact on patient outcome; however, perioperative management can greatly affect the consequences. A thorough knowledge of the impact of the disease on clinical status can determine how, when, and why to manage parturients with SCD.

Topics: Anemia, Sickle Cell; Anesthesia, Obstetrical; Bahrain; Blood Transfusion; Erythropoietin; Female; Fetal Hemoglobin; Haplotypes; Humans; Postoperative Care; Pregnancy; Pregnancy Complications, Hematologic; Pregnancy Outcome; Prenatal Care; Recombinant Proteins; Severity of Illness Index

Sickle cell disease is numerically as common as thalassaemia. However, it affects relatively under privileged population i.e. tribal population belonging to economically poor class and having inadequate access to education and modern health facilities. A recent explosion acknowledged in understanding the pathogenesis of this disease has lead to newer dimensions in treatment. Some of these viz. prevention of overwhelming bacterial infection, present indications and controversies regarding blood transfusion, prevention of stroke, acute chest syndrome, hydroxyurea therapy--probably the best disease modifying agent at the moment, stem cell transplantation--a cure and certain promising experimental therapies including gene therapy have been discussed in this review.

Topics: Acute Disease; Adolescent; Anemia, Sickle Cell; Antisickling Agents; Bacterial Infections; Blood Transfusion; Child; Child, Preschool; Erythropoietin; Humans; Hydroxyurea; Infant; Infant, Newborn; Recombinant Proteins; Respiratory Tract Diseases; Stem Cell Transplantation; Stroke; Syndrome

New drugs, recently available for treatment of different forms of anaemia, have somehow changed the therapeutic scenario in paediatric haematology. The aim of this review is to focus on the newest molecules discussing indications, clinical usefulness and related problems. Erythropoietin, the specific growth factor of red cell precursors, is now an established option for anaemia of chronic renal failure, prematurity, bone marrow transplantation and chemotherapy. Anti-CD20 monoclonal antibody, a novel cytotoxic molecule for mature B lymphocytes, has proven to be effective in the treatment of refractory autoimmune cytopenias. Haemoglobin analogues are currently under investigation, in order to obtain a synthetic oxygen-carrier that can substitute blood transfusions. Finally drugs that are able to increase the production of haemoglobin F have been used in thalassemias and haemoglobinopathies. For patients with sickle cell disease, hydroxyurea is no longer an experimental tool; it has given rise to several trials, where it has proven to be effective in terms of both clinical and haematological improvement.

Topics: Adult; Age Factors; Anemia; Anemia, Hemolytic, Autoimmune; Anemia, Sickle Cell; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Antisickling Agents; Blood Substitutes; Bone Marrow Transplantation; Butyrates; Child; Clinical Trials as Topic; Erythropoietin; Fetal Hemoglobin; Forecasting; Hemoglobinopathies; Hemoglobins; Humans; Hydroxyurea; Infant, Newborn; Infant, Premature, Diseases; Kidney Failure, Chronic; Organ Transplantation; Rituximab; Thalassemia; Tissue Donors

In patients with cardiovascular disease, partial correction of anaemia with epoetin improves quality of life and exercise capacity, and reduces left ventricular hypertrophy. The currently recommended haemoglobin in these patients is 11-12 g/dl. The optimal haemoglobin in patients with diabetes mellitus does not differ from that in non-diabetic patients; however, haemoglobin should be increased slowly. There is no difference in the recommended haemoglobin between children and adults. However, epoetin sensitivity is lower in children who, therefore, typically need the same absolute dose of epoetin as adults. Epoetin treatment may delay the progression of chronic renal failure (CRF) in paediatric patients. Elderly patients obtain similar benefits from epoetin as younger adults; moreover, there are no differences in the doses of epoetin required or the optimal haemoglobin. There are very few data available on the effects of epoetin in patients with CRF and chronic obstructive pulmonary disease. At present, a haemoglobin of 11 g/dl seems appropriate. In sickle-cell anaemia patients with CRF, a high haemoglobin could precipitate painful crises; consequently, the recommended haemoglobin is the pre-CRF concentration of 6-9 g/dl. There is no convincing evidence of any effect of previous epoetin treatment on the long-term outcome of renal transplantation. In patients with a failing or failed transplant, the required dose of epoetin may be higher than in pre-transplantation patients. In such cases, transplant nephrectomy might be considered.

Topics: Adult; Aged; Anemia; Anemia, Sickle Cell; Child; Diabetic Nephropathies; Erythropoietin; Humans; Kidney Failure, Chronic; Kidney Transplantation; Lung Diseases, Obstructive

Automated counting of reticulocytes has markedly increased the precision and accuracy of this assay compared with the traditional manual counts. In addition, several new reticulocyte parameters are now available to clinicians and pathologists. This review examines the potential role of these parameters in the diagnosis and management of anemias. Reticulocyte maturity can now be assessed based on the staining intensity of reticulocytes, which is proportional to their RNA content. However, the clinical value of the numerical estimate of the immature reticulocyte fraction has not been yet demonstrated. In the bone marrow transplant setting, there is no clear evidence that the use of this index results in improved care of these patients, and many studies have failed to show its superiority compared with the traditional white cell count, especially for autologous transplants. Direct measurement of reticulocyte volume, hemoglobin concentration, and hemoglobin content are now available. Studies have shown that these parameters, and hemoglobin content in particular, allow a real-time assessment of the functional state of the erythroid marrow. In the setting of recombinant human erythropoietin therapy, studies of hemoglobin content have shown that this index allows an early detection of functional iron deficiency. Preliminary studies have also shown that this index may be helpful in the diagnosis of iron deficiency and in the monitoring of iron replacement therapy.

Topics: Anemia, Hypochromic; Anemia, Megaloblastic; Anemia, Sickle Cell; Bone Marrow; Bone Marrow Diseases; Bone Marrow Transplantation; Cell Size; Cellular Senescence; Erythropoietin; Graft Survival; Hematologic Diseases; Hemoglobins; Humans; Iron Deficiencies; Recombinant Proteins; Reference Values; Reticulocyte Count; Reticulocytes; RNA; Staining and Labeling

Re-activation of the fetal globin genes is the most realistic approach to correct the deranged pathophysiology of the haemoglobinopathies because the presence of gamma-chains can neutralize the toxic effects of the unbound alpha-globin chains in the beta-thalassaemias and inhibit the polymerization of Hb S in the sickle cell syndromes. Re-induction of fetal haemoglobin synthesis can be brought about either by direct activation of the respective promoter genes and possibly other positively acting elements, or by recruitment into proliferation and differentiation of a population of erythroid precursors which retain the gamma-chain synthesis programme but remain dormant in the bone marrow of the adult unless called up in cases of acute erythroid expansion. Examples of the first group include the butyric acid and derivatives and 5' azacytidine. The second group comprises erythropoietin and a series of cytostatics, with hydroxyurea as the main representative. The activity of most of the above agents has already been studied in cell cultures and animals and confirmed in several patients, both at the haematological and biochemical level as well as through their frank clinical improvement. However, application of these drugs at large is not yet justified because a series of questions concerning their long-term efficacy, the correct dosage and timing, their tolerance and toxicity, and the potential long-term dangers, including mutagenicity are still unresolved.

Topics: Anemia, Sickle Cell; Antisickling Agents; Butyrates; Butyric Acid; Drug Therapy, Combination; Erythropoietin; Hemoglobinopathies; Humans; Hydroxyurea; Thalassemia

In the present review the role and regulation of foetal haemoglobin (HbF) in sickle-cell disease as well as the clinical results of therapy aimed at augmenting HbF synthesis are briefly discussed. Enhanced levels of HbF have an inhibitory effect on sickling and ameliorate the clinical course of sickle-cell disease. This knowledge has incited a search for pharmacological agents capable of stimulating HbF production. Cytostatic drugs, in particular hydroxyurea, but also other agents such as erythropoietin, butyrate and its analogues have been shown to induce HbF production. The mechanisms of action and the clinical effects of these agents are summarized. Only hydroxyurea has shown significant clinical effects in terms of reduction of pain-crises, chest syndrome and transfusions in sickle-cell patients. However, not all patients experience clinical amelioration and it appears difficult to predict which patient will gain from hydroxyurea therapy. Further studies need to expand the clinical experience with hydroxyurea, other HbF-inducing agents and combinations of these drugs. Moreover, they will hopefully provide criteria to enable appropriate selection of those patients with sickle-cell anaemia who will benefit clinically from HbF stimulation, also taking into account the risks and costs of long-term pharmacological therapy.

Topics: Anemia, Sickle Cell; Animals; Butyrates; Butyric Acid; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Infant, Newborn

Topics: Anemia, Sickle Cell; Antineoplastic Agents; Antisickling Agents; Azacitidine; beta-Thalassemia; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Phenylbutyrates

Transfusion is associated with improvement of life expectancy in beta thalassemia and sickle cell disease (SCD). Bone marrow transplantation concerns only a few patients. Among potentially useful therapeutic agents which can induce fetal hemoglobin (HbF) production, hydroxyurea (HU) stands out in particular for SCD. In our sickle cell center, 10 patients with SCD received HU for chronic leg ulcer with good results in terms of healing (7 among 10, who required no additional transfusion). A few patients, most of them over 30 years, received HU for chronic organ failure at the onset. HU on long term therapy over one year improved general status, Hb level, in 7 patients with beta thalassemia intermedia. A major challenge in the coming years will be the effective evaluation of clinical efficiency and the comparison of risks and benefits of such compounds versus transfusion.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Blood Substitutes; Butyrates; Child; Erythrocyte Transfusion; Erythropoietin; Hemoglobinopathies; Humans; Hydroxyurea; Middle Aged

Present concepts of the mechanism of reactivation of synthesis of fetal hemoglobin (HbF) in the adult under conditions of erythropoietic stress are briefly reviewed. Since HbF can be considered an effective natural antisickling agent, the reactivation of its synthesis in patients with sickle cell anemia as a desirable therapeutic goal has been extensively explored since the discovery in 1982 that 5-azacytidine increases HbF levels in the baboon. Hydroxyurea (HU) has become the most widely used agent, although its effectiveness in increasing HbF levels and the number of F cells is highly variable. Recent investigations are cited showing that other agents such as butyrate, and the addition of recombinant hemopoietic growth factors, such as erythropoietin and stem cell factor, especially in combination with HU, offer important therapeutic possibilities. Transacting nuclear proteins are briefly discussed as possibly having a future role in the efforts of stimulating gamma-chain synthesis.

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Butyrates; Butyric Acid; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Papio

The past decade has witnessed profound increases in knowledge of the structure, function, and developmental regulation of the human globin genes. This information has deepened our understanding of the molecular and cellular mechanisms underlying inherited disorders affecting hemoglobin, and it has provided a new perspective for attaining meaningful increases in fetal hemoglobin synthesis in the management of sickle cell anemia and beta thalassemia. Efforts to provide therapy for these disorders are based on three factors: an understanding of their pathophysiology; the potential for fetal hemoglobin to alter its manifestation; and the concept that developmental changes in globin gene expression might be reversed by manipulating cellular and molecular regulatory mechanisms. In this review we discuss these topics and examine critically recent efforts to apply various pharmacological agents to in vitro, animal, and human models with the goal of increasing HbF synthesis. Several agents have demonstrated activity in patients with hemoglobin disorders. One such agent, hydroxyurea, has been shown to be potentially efficacious in phase II clinical trials in patients with sickle cell anemia and awaits testing in a placebo-controlled phase III study.

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Erythropoietin; Fetal Hemoglobin; Gene Expression Regulation; Hemoglobinopathies; Humans; Hydroxyurea; Thalassemia

Topics: Anemia; Anemia, Sickle Cell; Animals; Erythropoiesis; Erythropoietin; Genes; Humans; Immunologic Factors; Kidney; Kidney Diseases; Mammals; Receptors, Cell Surface; Receptors, Erythropoietin; Recombinant Fusion Proteins

Hydroxyurea may be the most promising drug suggested thus far as a treatment for patients with sickle cell anemia, but its safety and efficacy remain unproved, and it probably will not be evaluable for several years. It is not "the answer" for the disease, it seems likely that crises will not be eliminated by treatment, and at this time its use should be reserved for seriously affected adult patients who can participate in a controlled clinical trial. Every hematologist, internist, or pediatrician sees a few patients who are so severely afflicted by sickle cell anemia that their lives seem totally blighted. It is very tempting to consider treating them with hydroxyurea, because the drug is available in any pharmacy, but it is equally important to consider whether the treatment would accomplish any more than treating the physician's own sense of futility, or making the patient feel that "something was being done." If hydroxyurea were as safe as folic acid, treatment for these purposes would be reasonable. It is not, but its use may still be appropriate (although illegal unless used under an Investigational New Drug Agreement, because its use for this purpose is not approved by the FDA). Whether or not it is legal, prescription of hydroxyurea for patients with sickle cell anemia would be ethical or proper only if the potential risks, the variability of the Hb F response, and the lack of proof of clinical efficacy were clearly explained to potential recipients.

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Erythropoietin; Humans; Hydroxyurea

During the last several years, studies in humans and experimental animals have identified several compounds that induce fetal hemoglobin in the adult. These include: cell-cycle-specific drugs, other cytotoxic drugs, butyric acid analogs, and erythropoietin. Several of these compounds induce fetal hemoglobin indirectly by triggering kinetics of rapid erythroid regeneration. High doses of erythropoietin increase the frequency of erythroid progenitors programmed to hemoglobin F. This results in transient increases of hemoglobin F-containing cells (F cells) in the peripheral blood. Erythropoietin and hydroxyurea increase F cells in a cooperative fashion. Although high doses of erythropoietin can induce F cell production in humans, the practical relevance of such observations is unclear

Topics: Anemia, Sickle Cell; Animals; Cell Cycle; Erythroid Precursor Cells; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Recombinant Proteins

Topics: Anemia, Sickle Cell; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Thalassemia

Recombinant human erythropoietin represents a potential therapeutic alternative to red blood cell transfusions in a number of pediatric anemias. It is effective in correcting anemia associated with chronic renal failure and may significantly reduce the morbidity associated with childhood CRF. Most exposures to allogeneic blood products in pediatrics for treatment of anemia with blood transfusions occur in neonatal intensive care units. If proven effective in treating anemia in premature babies, r-HuEPO will be responsible for a major reduction in the use of blood transfusions in clinical neonatology. Carefully designed, placebo-controlled clinical trials will be required to establish the role of r-HuEPO in anemia of prematurity. Recombinant human erythropoietin also may be useful to increase the amount of blood that can be collected before elective surgical procedures. Another potential indication is to raise the hematocrits of infants with large intracardiac shunts who develop congestive heart failure coincident with the developmental fall in hemoglobin concentration after birth. Finally, r-HuEPO may one day play a role in modifying the expression of globin genes and, thereby, ameliorate the course of sickle cell disease and beta thalassemia. Many questions surrounding the use of r-HuEPO in infancy and childhood are being addressed in ongoing clinical trials.

Topics: Anemia; Anemia, Sickle Cell; Blood Transfusion, Autologous; Erythropoietin; Humans; Infant, Newborn; Infant, Premature, Diseases; Kidney Failure, Chronic; Recombinant Proteins

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Clinical Trials as Topic; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Interleukin-3; Papio; Recombinant Proteins

Topics: Anemia, Sickle Cell; Animals; Cell Count; Erythroid Precursor Cells; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Reticulocytes

There have been numerous new contributions to the knowledge of foetal haemoglobin over the last few years. It is, therefore, timely to review them together. They throw light on the arrangement on the chromosome of non-alpha chain genes, and on the condition generally known as Hereditary Persistence of Foetal Haemoglobin (HPFH) and have contributed to other aspects of human ontogeny and physiology.

Topics: Adult; Amino Acid Sequence; Anemia, Aplastic; Anemia, Sickle Cell; Child; Erythrocytes; Erythropoietin; Female; Fetal Blood; Fetal Hemoglobin; Genes; Genetic Linkage; Genetic Variation; Genetics, Population; Hemoglobinopathies; Humans; Infant; Infant, Newborn; Leukemia; Oxygen; Pregnancy; Protein Denaturation; Suppression, Genetic; Thalassemia

Previous studies have suggested that erythropoietin (Epo) levels may be inappropriately low in patients with sickle cell disease compared to the extent of the related anemia they demonstrate. Here, we evaluate Epo level vs. renal function, oxygenation, and markers of inflammation for patients treated for sickle cell disease at our institution. Blood was drawn from 54 patients with sickle cell disease during routine visits to the outpatient hematology office and analyzed for hemoglobin (Hb) level, Epo, markers of inflammation, oxygenation, and renal function. Erythropoietin levels were lower than expected for patients with sickle cell disease, compared to the degree of anemia demonstrated in these patients. In addition, a correlation between Hb level and Epo was not consistently observed. Higher Epo levels were seen in patients receiving hydroxyurea (HU), but no correlation with oxygenation, hemolysis, renal function, or inflammation was observed.

Topics: Adult; Aged; Anemia, Sickle Cell; Antisickling Agents; Biomarkers; Erythropoietin; Female; Hemoglobins; Hemolysis; Humans; Hydroxyurea; Inflammation; Kidney Function Tests; Male; Middle Aged

Hepcidin, a regulator for iron homeostasis, is induced by inflammation and iron burden and suppressed by anemia and hypoxia. This study was conducted to determine the hepcidin levels in patients with congenital chronic anemias.. Forty-nine subjects with anemia, varying degrees of erythropoiesis and iron burden were recruited. Eight children with immune thrombocytopenia were included as approximate age-matched controls. Routine hematologic labs and urinary hepcidin (uhepcidin) levels were assessed. For thalassemia major (TM) patients, uhepcidin was obtained pre- and post-transfusion.. In TM, uhepcidin levels increased significantly after transfusion, demonstrated wide variance, and the median did not significantly differ from controls or thalassemia intermedia (TI). In both thalassemia syndromes, the hepcidin to ferritin ratio, a marker of the appropriateness of hepcidin expression relative to the degree of iron burden, was low compared to controls. In TI and sickle cell anemia (SCA), median uhepcidin was low compared to controls, P = 0.013 and <0.001, respectively. In thalassemia subjects, uhepcidin levels were positively associated with ferritin. In subjects with SCA, uhepcidin demonstrated a negative correlation with reticulocyte count.. This study examines hepcidin levels in congenital anemias. In SCA, hepcidin was suppressed and inversely associated with erythropoietic drive. In thalassemic syndromes, hepcidin was suppressed relative to the degree of iron burden. Transfusion led to increased uhepcidin. In thalassemia, the relative influence of known hepcidin modifiers was more difficult to assess. In thalassemic syndromes where iron overload and anemia have opposing effects, the increased erythropoietic drive may positively influence hepcidin production.

Topics: Adolescent; Adult; Aged; Anemia, Sickle Cell; Antimicrobial Cationic Peptides; beta-Thalassemia; Biomarkers; Blood Transfusion; Child; Child, Preschool; Erythropoietin; Female; Gene Expression Regulation; Hepcidins; Humans; Iron; Male; Middle Aged; Purpura, Thrombocytopenic, Idiopathic; Reticulocyte Count; Syndrome

The use of hydroxyurea for the prevention of sickle cell crises in patients with homozygous HbS disease is now well established. The beneficial effects of this compound stem from (a) selective enrichment of red cells containing an increased amount of fetal hemoglobin, which inhibits HbS polymerization, and (b) a decrease of leukocytes, platelets, and reticulocytes, which significantly limits their adherence to the vascular wall. We report the results of a clinical trial of hydroxyurea on 55 Greek-origin patients with sickle cell/beta-thalassemia and 14 patients with homozygous HbS disease who have been treated with hydroxyurea for several years. Such patients have a higher probability to benefit from hydroxyurea therapy, since in addition to its antisickling effect, the increase of gamma-chain synthesis is expected to diminish the deleterious effects of the unbound alpha-globin chains. Selection of patients and monitoring throughout the whole trial were done by the same clinicians. Quantitative expression of the clinical condition was done using a system scoring several outcome parameters. For a period of 52 months prior to starting treatment, the total score of severity for 59 evaluable patients was 1182 points (3068 patient-weeks), while for the 12,018 patient-weeks of the trial this parameter fell to only 82 points. Other observations of interest include the significant improvement of a group of patients with hepatic cholestasis, the development of leg ulcers possibly related to the treatment, and the dramatic increase of hemoglobin F, often in association with an increase of the total hemoglobin levels as a result of decreased hemolysis.

Topics: Acute Disease; Adolescent; Adult; Anemia, Sickle Cell; Antisickling Agents; beta-Thalassemia; Erythrocyte Count; Erythrocyte Indices; Erythrocytes; Erythropoietin; Female; Fetal Hemoglobin; Greece; Hemoglobins; Humans; Hydroxyurea; Leg Ulcer; Male; Middle Aged; Pancreatitis; Patient Compliance; Patient Selection; Receptors, Transferrin; Severity of Illness Index

The clinical effectiveness of Hydroxyurea in thalassemia is still controversial. The present paper puts together the authors' experience in two groups of patients with thalassemia intermedia and sickle cell/beta-thalassemia treated with varying dosages of hydroxyurea over several months. A third group received hydroxyurea along with recombinant human erythropoietin. Our observations are summarized in that treatment with hydroxyrea results in a significant increase of fetal hemoglobin with no change of the total hemoglobin levels. The drug causes also a considerable increase of the erythrocyte volume and hemoglobin content while the MCHC values remain unchanged. As a rule, and without objective criteria so far, patients state feeling better and having more energy. The authors postulate that this feeling may reflect the significant decrease of ineffective erythropoiesis resulting by the replacement of the poorly hemoglobinized, prematurely dying erythroid progenitor and red cell population by another population of cells with higher hemoglobin content and longer survival, the regeneration of which requires less energy and consumption. As expected, patients with sickle cell/beta-thalassemia have also fewer crises and painful episodes. The above findings are in keeping with the few available reports in the literature.

Topics: Anemia, Sickle Cell; Antisickling Agents; beta-Thalassemia; Drug Therapy, Combination; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Hemoglobins; Humans; Hydroxyurea; Recombinant Proteins

Topics: Adolescent; Adult; Anemia, Sickle Cell; beta-Thalassemia; Erythropoietin; Female; Fetal Hemoglobin; Hemoglobin A; Humans; Postpartum Period; Pregnancy; Pregnancy Complications, Hematologic; Pregnancy Trimester, Third; Recombinant Proteins

Seven sickle cell disease (SCD) patients [sickle cell anaemia = 4 (males 2, females 2, age range 18-40 years), and sickle cell beta (0)-thalassaemia = 3 (all females, age range 20-47 years)], suffering from a severe form of the disease were enrolled in a treatment protocol using hydroxyurea (HU) for up to 12 months followed by a combination therapy with HU and human recombinant erythropoietin (rHuEpo; using 400 U/kg/week i.v.) for 3-4 weeks. Following the withdrawal of rHuEpo the patients were maintained on HU alone. The patients were characterised on the basis of the 'severity index' prior to the initiation of the therapy. Haematological and relevant biochemical parameters, Hb A2 fetal haemoglobin (HbF), HbF cells, reticulocytes and platelet counts were estimated at least at three occasions to determine the mean and range of the parameters. During the treatment period the patients were followed every 2-4 weeks where the haematological and biochemical parameters were assessed. The results were separately analysed and mean +/- SD were obtained for each parameter at the end of each protocol. The statistical significance of the difference in the results obtained on treatment and the baseline results was examined using the paired t test. No toxic side effects of HU and rHuEpo (as judged from reduction in platelet and white blood cell count) were documented during and after the whole period of treatment. The patients showed a significant clinical improvement. Total haemoglobin, haematocrit, red cell count, HbF and HbF cells increased, while white blood cells, reticulocyte counts and bilirubin level decreased. Platelet count decreased but remained within the normal range. The results revealed that 5 of the patients on HU treatment showed a significant increase in the HbF level and HbF cells, while 2 patients (1 sickle cell anaemia and 1 Hb S/beta(0)-thalassaemia patient) did not and were considered as 'non-responders'. The rHuEpo and HU combination therapy elevated the HbF level, with a varying degree, in all patients except 2, who had already reached a high HbF level and showed a decrease in HbF during the rHuEpo protocol. Variable individual response to both HU and rHuEpo therapy was a common feature. We recommend the use of HU for the treatment of SCD and a combination therapy using HU and rHuEpo for the non-responders.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Antisickling Agents; beta-Thalassemia; Drug Therapy, Combination; Erythropoietin; Female; Humans; Hydroxyurea; Male; Middle Aged; Recombinant Proteins

Butyrate analogues have been shown to increase fetal hemoglobin (HbF) production in vitro and in vivo. Sodium phenylbutyrate (SPB), an oral agent used to treat individuals with urea-cycle disorders, has been shown to increase HbF in nonanemic individuals and in individuals with sickle cell disease. We have treated eleven patients with homozygous beta thalassemia (three transfusion dependent) and one sickle-beta-thalassemia patient with 20 g/d (forty 500-mg tablets) of SPB for 41 to 460 days. All patients showed an increase in the percent of F reticulocytes associated with treatment, but only four patients responded by increasing their Hb levels by greater than 1 g/dL (mean increase, 2.1 g/dL; range, 1.2 to 2.8 g/dL). None of the transfusion-dependent thalassemia subjects responded. Increase in Hb was associated with an increase in red blood cell number (mean increase, 0.62 x 10(12)/L), and mean corpuscular volume (mean increase, 6 fL). Changes in percent HbF, absolute HbF levels, or alpha- to non-alpha-globin ratios as measured by levels of mRNA and globin protein in peripheral blood did not correlate with response to treatment. Response to treatment was not associated with the type of beta-globin mutation, but baseline erythropoietin levels of greater than 120 mU/mL was seen in all responders and only two of eight nonresponders to SPB. Compliance with treatment was greater than 90% as measured by pill counts. Side effects of the drug included weight gain and/or edema caused by increase salt load in 2/12, transient epigastric discomfort in 7/12, and abnormal body odor in 3/12 subjects. Two splenectomized patients who were not on prophylactic antibiotics developed sepsis while on treatment. We conclude that SPB increases Hb in some patients with thalassemia, but the precise mechanism of action is unknown.

Topics: Adult; Anemia, Sickle Cell; beta-Thalassemia; Blood Transfusion; Erythropoietin; Female; Fetal Hemoglobin; Globins; Hemoglobins; Hemolysis; Homozygote; Humans; Male; Mutation; Patient Compliance; Phenylbutyrates; Reticulocytes

Topics: Administration, Inhalation; Anemia, Sickle Cell; Arterial Occlusive Diseases; Blood Cell Count; Erythropoiesis; Erythropoietin; Hemoglobins; Humans; Length of Stay; Oxygen; Prospective Studies; Reticulocytes; Treatment Outcome

Studies on baboons and preliminary observations in three patients with sickle cell anemia (SS) suggested that high doses of pulse administered recombinant human erythropoietin (rHuEPO) stimulate F-reticulocyte production. We now report on the administration of rHuEPO in a double-blind format to ascertain frequency of response and potential precipitation of side effects. Ten patients were enrolled, but one was discontinued due to the indication of a blood transfusion. Of the other nine, five received rHuEPO in escalating doses (from 400 to 1,500 U per kg twice daily [BID] per week), alternating with a placebo, in blinded fashion. The second group, consisting of four patients, followed an identical protocol (except starting dose was 1,000 U/Kg, BID per week) and were iron supplemented during treatment. The criterion of response was a transient doubling (as a minimum) of the steady-state F-reticulocyte level. We found that none of the five patients in the first group responded to rHuEPO, and two of them became iron deficient, as judged by a significant decrease in ferritin. Of the second group, four patients responded with F-reticulocyte increases. In three patients, open label administration of rHuEPO confirmed the effect. We observed seven painful episodes during this study, two during the EPO administration and five during the placebo arm. Three patients were phlebotomized because the hemoglobin level increased 1.5 g/dL more than steady-state levels. Of the six patients followed-up by percent dense cell determinations, one exhibited increased levels during periods of the treatment, whereas the other five showed no change. No anti-rHuEPO antibodies were detected. We conclude that rHuEPO can stimulate F-reticulocyte response in some patients with sickle cell anemia, without apparent negative clinical side effects. The state of iron stores may be critical. Whether higher doses of rHuEPO and/or a different regimen might induce sustained F cells and fetal hemoglobin increases remains to be determined.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Double-Blind Method; Erythrocyte Count; Erythropoietin; Female; Ferritins; Ferrous Compounds; Humans; Male; Middle Aged; Recombinant Proteins; Reticulocytes

Hydroxyurea has been shown to increase fetal hemoglobin (Hb F) production in patients with sickle cell disease and therefore has the potential to alleviate both the hemolytic and vaso-occlusive manifestations of the disease. Preliminary evidence indicates that recombinant human erythropoietin (rhEpo) may also induce Hb F. Three sickle cell anemia patients were treated with escalating doses of intravenous rhEpo and, subsequently, with daily oral hydroxyurea. After the optimal hydroxyurea dose was attained, rhEpo was added again. Two additional patients were treated with hydroxyurea alone. Treatment with rhEp, either alone or in combination with hydroxyurea, had no significant effect on the percentage of F reticulocytes or F cells. In contrast, hydroxyurea treatment was associated with a 1.5-fold to sevenfold increase in F cells and a 2.3- to 27-fold increase in the percentage of Hb F. In the three patients whose response reached a plateau, hydroxyurea treatment was associated with lessened hemolysis, decreased serum bilirubin and lactate dehydrogenase levels, and prolonged 51chromium-labeled RBC survival. Hydroxyurea treatment also resulted in decreased numbers of irreversibly sickled cells and in decreased sickling at partial oxygen saturation, increased oxygen affinity, increased total RBC cation content, and diminished potassium:chloride co-transport. All five patients treated with hydroxyurea experienced a decrease in severity and frequency of painful sickle crises. This study confirms that hydroxyurea therapy increases Hb F production and provides objective evidence of a significant reduction in hemolytic rate and intracellular polymerization. In contrast, rhEpo, either alone or in combination with hydroxyurea, offered no measurable benefit. Based on these encouraging preliminary data, large-scale, controlled clinical trials are warranted to study the safety and efficacy of hydroxyurea in the treatment of sickle cell disease.

Topics: Administration, Oral; Anemia, Sickle Cell; Drug Administration Schedule; Drug Combinations; Erythrocytes; Erythropoietin; Fetal Hemoglobin; Hemoglobin, Sickle; Humans; Hydroxyurea; Injections, Intravenous; Oxyhemoglobins; Recombinant Proteins; Reticulocytes

Hydroxyurea may be the most promising drug suggested thus far as a treatment for patients with sickle cell anemia, but its safety and efficacy remain unproved, and it probably will not be evaluable for several years. It is not "the answer" for the disease, it seems likely that crises will not be eliminated by treatment, and at this time its use should be reserved for seriously affected adult patients who can participate in a controlled clinical trial. Every hematologist, internist, or pediatrician sees a few patients who are so severely afflicted by sickle cell anemia that their lives seem totally blighted. It is very tempting to consider treating them with hydroxyurea, because the drug is available in any pharmacy, but it is equally important to consider whether the treatment would accomplish any more than treating the physician's own sense of futility, or making the patient feel that "something was being done." If hydroxyurea were as safe as folic acid, treatment for these purposes would be reasonable. It is not, but its use may still be appropriate (although illegal unless used under an Investigational New Drug Agreement, because its use for this purpose is not approved by the FDA). Whether or not it is legal, prescription of hydroxyurea for patients with sickle cell anemia would be ethical or proper only if the potential risks, the variability of the Hb F response, and the lack of proof of clinical efficacy were clearly explained to potential recipients.

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Erythropoietin; Humans; Hydroxyurea

Topics: Anemia; Anemia, Sickle Cell; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Recombinant Proteins; Renal Dialysis

Topics: Anemia, Sickle Cell; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Thalassemia

Topics: Anemia, Sickle Cell; Animals; Azacitidine; Clinical Trials as Topic; Erythropoietin; Fetal Hemoglobin; Humans; Hydroxyurea; Interleukin-3; Papio; Recombinant Proteins

α-Thalassemia is one of the most important genetic modulators of sickle cell disease (SCD). Both beneficial and detrimental effects have been described previously. We use a 12-year data set on a large cohort of patients with HbSS (n = 411) and HbSC (n = 146) to examine a wide range of these clinical and laboratory associations. Our novel findings are that α-thalassemia strongly reduces erythrocyte potassium chloride co-transporter (KCC) activity in both HbSS and HbSC (p = .035 and p = .00045 respectively), suggesting a novel mechanism through which α-thalassemia induces a milder phenotype by reducing red cell cation loss. This may be particularly important in HbSC where reduction in mean cell hemoglobin concentration is not seen and where KCC activity has previously been found to correlate with disease severity. Additionally, we show that α-thalassemia not only increases hemoglobin in patients with HbSS (p = .0009) but also reduces erythropoietin values (p = .0005), demonstrating a measurable response to improved tissue oxygenation. We confirm the reno-protective effect of α-thalassemia in patients with HbSS, with reduced proteinuria (p = .003) and demonstrate a novel association with increased serum sodium (p = .0004) and reduced serum potassium values (p = 5.74 × 10

Topics: alpha-Thalassemia; Anemia, Sickle Cell; Cations; Erythrocytes; Erythropoietin; Hemoglobin SC Disease; Hemoglobin, Sickle; Humans

Among the severe malaria syndromes, severe malarial anemia (SMA) is the most common, whereas cerebral malaria (CM) is the most lethal. However, the mechanisms that lead to CM and SMA are unclear.. We compared transcriptomic profiles of whole blood obtained from Ugandan children with acute CM (n = 17) or SMA (n = 17) and community children without Plasmodium falciparum infection (n = 12) and determined the relationships among gene expression, hematological indices, and relevant plasma biomarkers.. Both CM and SMA demonstrated predominantly upregulated enrichment of dendritic cell activation, inflammatory/Toll-like receptor/chemokines, and monocyte modules, but downregulated enrichment of lymphocyte modules. Nuclear factor, erythroid 2 like 2 (Nrf2)-regulated genes were overexpressed in children with SMA relative to CM, with the highest expression in children with both SMA and sickle cell disease (HbSS), corresponding with elevated plasma heme oxygenase-1 in this group. Erythroid and reticulocyte-specific signatures were markedly decreased in CM relative to SMA despite higher hemoglobin levels and appropriate increases in erythropoietin. Viral sensing/interferon-regulatory factor 2 module expression and plasma interferon-inducible protein-10/CXCL10 negatively correlated with reticulocyte-specific signatures.. Compared with SMA, CM is associated with downregulation of Nrf2-related and erythropoiesis signatures by whole-blood transcriptomics. Future studies are needed to confirm these findings and assess pathways that may be amenable to interventions to ameliorate CM and SMA.

Topics: Anemia; Anemia, Sickle Cell; Biomarkers; Chemokine CXCL10; Chemokines; Child; Child, Preschool; Dendritic Cells; Down-Regulation; Erythroid Cells; Erythropoiesis; Erythropoietin; Female; Gene Expression Profiling; Gene Expression Regulation; Heme Oxygenase-1; Hemoglobins; Humans; Infant; Interferon Regulatory Factor-2; Malaria, Cerebral; Malaria, Falciparum; Male; Monocytes; NF-E2-Related Factor 2; Plasmodium falciparum; Reticulocytes; Toll-Like Receptors; Transcriptome; Uganda

Topics: Adult; Anemia, Sickle Cell; Erythrocyte Transfusion; Erythropoietin; Female; Hemoglobins; Humans; Male; Middle Aged; Recombinant Proteins

Topics: Adult; Anemia, Sickle Cell; Darbepoetin alfa; Erythropoietin; Hematinics; Humans; Male; Retrospective Studies

Topics: Adult; Anemia, Sickle Cell; Animals; Benzaldehydes; Cerebrovascular Circulation; Child; Clinical Trials as Topic; Double-Blind Method; Drug Evaluation, Preclinical; Erythropoietin; Gene Knock-In Techniques; Hematologic Agents; Hemoglobin, Sickle; Humans; Hypoxia; Mice; Mice, Transgenic; Oxygen; Polymerization; Pyrazines; Pyrazoles; Reticulocytes

To investigate the pattern of CD55 and CD59 expression on RBCs of SCD patients, and its association with anemia, biochemical parameters of hemolysis, level of erythropoietin, and pro-inflammatory markers.. Flow cytometric analysis was performed on RBCs from 71 adult SCD patients and 53 healthy controls, using the commercial REDQUANT kit.. CD59 deficiency was significantly higher among SCD patients than among healthy controls. The proportions of CD55-deficient and CD59-deficient RBCs from SCD patients were significantly higher when compared with those from healthy controls (0.17 vs. 0.09 and 2.1 vs. 1.2, respectively). The MFI of CD55 and CD59 expression on RBCs in SCD was significantly reduced when compared to the expression in healthy controls (5.2 vs. 6.4 and 19.4 vs 20.3, respectively). The pattern of CD55 and CD59 expression was not correlated with anemia, biomarkers of hemolysis, erythropoietin level, or other pro-inflammatory markers.. There is an altered pattern of CD55 and CD59 expression on RBCs of SCD Patients; however, it does not seem to play a causal role in the pathophysiology of anemia, and is unlikely to be influenced by the level of erythropoietin or other inflammatory mediators.

Topics: Adult; Anemia, Sickle Cell; CD55 Antigens; CD59 Antigens; Erythrocytes; Erythropoietin; Female; Flow Cytometry; Humans; Male; Young Adult

Placental growth factor (PlGF) plays an important role in various pathological conditions and diseases such as inflammation, cancer, atherosclerosis and sickle cell disease (SCD). Abnormally high PlGF levels in SCD patients are associated with increased inflammation and pulmonary hypertension (PHT) and reactive airway disease; however, the transcriptional and post-transcriptional mechanisms regulating PlGF expression are not well defined. Herein, we show that treatment of human erythroid cells and colony forming units with erythropoietin (EPO) increased PlGF expression. Our studies showed EPO-mediated activation of HIF-1α led to subsequent binding of HIF-1α to hypoxia response elements (HREs) within the PlGF promoter, as demonstrated by luciferase transcription reporter assays and ChIP analysis of the endogenous gene. Additionally, we showed miR-214 post-transcriptionally regulated the expression of PlGF as demonstrated by luciferase reporter assays using wild-type (wt) and mutant PlGF-3'-UTR constructs. Furthermore, synthesis of miR-214, located in an intron of DNM3 (dynamin 3), was transcriptionally regulated by transcription factors, peroxisome proliferator-activated receptor-α (PPARα) and hypoxia-inducible factor-1α (HIF-1α). These results were corroborated in vivo wherein plasma from SCD patients and lung tissues from sickle mice showed an inverse correlation between PlGF and miR-214 levels. Finally, we observed that miR-214 expression could be induced by fenofibrate, a Food and Drug Administration (FDA) approved PPARα agonist, thus revealing a potential therapeutic approach for reduction in PlGF levels by increasing miR-214 transcription. This strategy has potential clinical implications for several pathological conditions including SCD.

Topics: 3' Untranslated Regions; Anemia, Sickle Cell; Animals; Cell Line; Cells, Cultured; Crosses, Genetic; Erythroid Cells; Erythroid Precursor Cells; Erythropoietin; Genes, Reporter; Hematinics; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lung; Mice; Mice, Inbred C57BL; Mice, Transgenic; MicroRNAs; Mutation; Placenta Growth Factor; Pregnancy Proteins; Promoter Regions, Genetic; Recombinant Proteins; RNA Interference

Topics: Adult; Anemia, Sickle Cell; Antisickling Agents; Erythropoiesis; Erythropoietin; Female; Hemoglobins; Humans; Hydroxyurea; Hypoxia; Male; Middle Aged; Oxygen Inhalation Therapy; Pain; Reticulocyte Count; Retrospective Studies; Sleep Disorders, Intrinsic; Treatment Outcome; Young Adult

Two of the most ethically complex situations in pediatrics are those involving families whose religious beliefs preclude the provision of life-sustaining treatment and those involving young adults who have reached the age of legal majority and who face decisions about life-sustaining treatment. This month's "Ethics Rounds" presents a case in which these 2 complexities overlapped. An 18-year-old Jehovah's Witness with sickle cell disease has life-threatening anemia. She is going into heart failure. Her doctors urgently recommend blood transfusions. The young woman and her family adamantly refuse. Should the doctors let her die? Is there any alternative?

Topics: Adolescent; Anemia, Sickle Cell; Blood Transfusion; Combined Modality Therapy; Critical Care; Erythropoietin; Ethics Committees, Clinical; Ethics, Medical; Female; Heart Failure; Hemoglobinometry; Humans; Hydroxyurea; Informed Consent; Jehovah's Witnesses; Patient Care Team; Professional-Family Relations; Professional-Patient Relations; Prognosis; Recombinant Proteins; Religion and Medicine; Treatment Refusal; Trust

CNTO 530 is an erythropoietin receptor agonist MIMETIBODYTM construct. CNTO 530 has been shown to be active in a number of rodent models of acquired anemia (e.g. renal insufficiency and chemotherapy induced anemia). We investigated the efficacy of CNTO 530 in murine models of β-thalassemia and sickle cell anemia (Berkeley mice). β- thalassemic mice are deficient in expression of α-globin chain and heterozygous mice are characterized by a clinical syndrome similar to the human β-thalassemia intermedia. Berkeley mice are knocked out for murine alpha and beta globin and are transgenic for human alpha, beta (sickle) and gamma globin genes. Berkeley mice thus express human sickle hemoglobin A (HbS) and can also express human fetal hemoglobin. These mice express a severe compensated hypochromic microcytic anemia and display the sickle cell phenotype. To test the effectiveness of CNTO 530, mice from both genotypes received a single subcutaneous (s.c.) dose of CNTO 530 or darbepoetin-α (as a comparator) at 10,000 U/kg, a dose shown to cause a similar increase in reticulocytes and hemoglobin in normal mice. Hematologic parameters were evaluated over time. CNTO 530, but not darbepoetin-α, increased reticulocytes, red blood cells and total hemoglobin in β- thalassemic mice. In Berkeley mice CNTO 530 showed an increase in reticulocytes, red blood cells, F-cells, total hemoglobin and fetal hemoglobin. In conclusion, CNTO 530 is effective in murine models of β-thalassemia and sickle cell anemia. These data suggest that CNTO 530 may have beneficial effects in patients with genetically mediated hemoglobinopathies.

Topics: Anemia, Sickle Cell; Animals; beta-Thalassemia; Darbepoetin alfa; Disease Models, Animal; Erythrocyte Count; Erythropoietin; Female; Hematinics; Hemoglobins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptors, Erythropoietin; Recombinant Fusion Proteins

In sickle cell disease (SCD), vigorous reticulocytosis is required to partially compensate for chronic hemolytic anaemia. Consequently, early renal damage, insufficient to cause azotemia but sufficient to cause erythropoietin deficiency and chronic relative reticulocytopenia (chRR), could have severe clinical consequences. chRR was defined as reticulocytes <250×10(9) /l despite haemoglobin <9 g/dl on ≥ two occasions ≥4 weeks apart. The influence of multiple variables including chRR on time from first clinic visit to death was evaluated in 306 SCD patients. In univariate analyses, fetal haemoglobin, indices of renal damage (serum creatinine, proteinuria), chRR and age, were associated with rate of death. In multivariate analysis, only age and chRR (Hazard ratio 3·6, 95% CI 2·049-6·327, P<0·0001) were significant, underlining that chRR could be an early and important clinical consequence of renal damage. Even in chRR patients with normal serum creatinine levels, low haemoglobin and low reticulocyte counts were associated with low erythropoietin levels. In the general population, evaluation of erythropoietin levels is prompted by the combination of anaemia and abnormal serum creatinine. In SCD patients, this standard approach can miss a substantial risk factor for early death. chRR could be a practical and important criterion for diagnosis of erythropoietin deficiency in SCD.

Topics: Adolescent; Adult; Age Factors; Anemia, Sickle Cell; Chronic Disease; Creatinine; Epidemiologic Methods; Erythropoietin; Female; Humans; Male; Middle Aged; Proteinuria; Reticulocyte Count; Young Adult

Topics: Anemia, Sickle Cell; Child; Child, Preschool; Erythropoietin; Female; Humans; Hydroxyurea; Preoperative Care

In this case, a female Nigerian patient suffered from sickle cell disease (SCD, hemoglobin SS)-induced chronic renal failure and was undergoing hemodialysis treatment. Due to SCD crisis and renal anemia the patient received regular blood transfusions when the hemoglobin concentration fell below 5.0 g/L. Blood transfusion associated iron-overload was noticed. To reduce the iron-overload side effects, we started an erythropoietin therapy (darbepoetin) to extend the blood transfusion interval, using 30-150 microg/week. As a result of our investigation we observed that darbepoetin can significantly extend blood transfusion intervals without increasing SCD crisis. To substantiate our observation, further investigations are needed with more SCD patients undergoing regular hemodialysis treatment.

Topics: Anemia, Sickle Cell; Blood Transfusion; Darbepoetin alfa; Dose-Response Relationship, Drug; Erythropoietin; Female; Hematinics; Hemoglobins; Humans; Kidney Failure, Chronic; Middle Aged; Nigeria; Renal Dialysis

Circulating endothelial progenitor cells (EPCs) counts were determined in patients with sickle cell disease (SCD) to elucidate their role in SCD-related ischemia-induced angiogenesis and reendothelialization.. Circulating EPC counts (KDR(+)/CD34(+)/Cd45(dim) cells) and their relation to serum levels of EPC mobilizing growth factors erythropoietin, vascular endothelial growth factor, and interleukin-8 were investigated in SCD patients during asymptomatic state (n=66) and painful crisis (n=36) and compared to healthy controls (n=13).. EPC counts were comparable between controls (0; range, 0-1.1 cells/mL) and patients (0; range, 0-0 cells/mL) in asymptomatic state, but were significantly higher during painful crisis (41.7; range, 0-186 cells/mL; p<0.05). Also in a paired analysis of 12 patients who were included both during asymptomatic state and painful crisis, EPC counts increased significantly during painful crisis (from 0 [range, 0-0] to 26 [range, 0-149 cell/mL; p<0.05). EPC counts were not related to any of the measured growth factors.. The higher EPC counts during painful crisis might indicate a role for EPC mobilization in reendothelialization. As a relationship of EPCs with the established mobilizing growth factors, measured in this study was not observed, the mechanism of EPC mobilization in SCD remains to be elucidated.

Topics: Adult; Anemia, Sickle Cell; Endothelial Cells; Erythropoietin; Female; Humans; Interleukin-8; Ischemia; Leukocyte Count; Male; Neovascularization, Pathologic; Pain; Stem Cells; Vascular Endothelial Growth Factor A

Hydroxyurea and higher hemoglobin F improve the clinical course and survival in sickle cell disease, but their roles in protecting from pulmonary hypertension are not clear. We studied 399 children and adolescents with sickle cell disease at steady state; 38% were being treated with hydroxyurea. Patients on hydroxyurea had higher hemoglobin concentration and lower values for a hemolytic component derived from 4 markers of hemolysis (P < or = .002) but no difference in tricuspid regurgitation velocity compared with those not receiving hydroxyurea; they also had higher hemoglobin F (P < .001) and erythropoietin (P = .012) levels. Hemoglobin F correlated positively with erythropoietin even after adjustment for hemoglobin concentration (P < .001). Greater hemoglobin F and erythropoietin each independently predicted higher regurgitation velocity in addition to the hemolytic component (P < or = .023). In conclusion, increase in hemoglobin F in sickle cell disease may be associated with relatively lower tissue oxygen delivery as reflected in higher erythropoietin concentration. Greater levels of erythropoietin or hemoglobin F were independently associated with higher tricuspid regurgitation velocity after adjustment for degree of hemolysis, suggesting an independent relationship of hypoxia with higher systolic pulmonary artery pressure. The hemolysis-lowering and hemoglobin F-augmenting effects of hydroxyurea may exert countervailing influences on pulmonary blood pressure in sickle cell disease.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Antisickling Agents; Child; Child, Preschool; Erythropoietin; Female; Fetal Hemoglobin; Humans; Hydroxyurea; Male; Tricuspid Valve Insufficiency; Young Adult

Deferasirox is a new iron chelator approved recently for chelation therapy in iron-overloaded patients. It is considered safe and efficacious in most patients, but has not been tested formally in patients with end-stage renal disease. We report a case of a patient with end-stage renal disease secondary to sickle cell nephropathy who developed recurrent symptomatic hypocalcemia while on therapy and later reexposure with this medication for iron overload from long-term blood transfusions. This is the first case report of this complication with deferasirox therapy in a patient with end-stage renal disease.

Topics: Adult; Anemia, Sickle Cell; Benzoates; Deferasirox; Erythropoietin; Female; Humans; Hypertension; Hypocalcemia; Iron Chelating Agents; Iron Overload; Kidney Failure, Chronic; Peritoneal Dialysis; Transfusion Reaction; Triazoles

Topics: Adult; Anemia, Sickle Cell; Erythropoietin; Female; Hematinics; Humans; Jehovah's Witnesses; Pregnancy; Pregnancy Complications, Hematologic; Recombinant Proteins

Hypoxia-induced angiogenesis may play an important role in the pathophysiology of sickle cell disease (SCD). Serum levels of angiopoietin (Ang)-1, Ang-2, vascular endothelial growth factor, placenta growth factor (PlGF), soluble tunica intima endothelial kinase 2 (sTIE2), erythropoietin (EPO) and endothelial activation markers (soluble vascular adhesion molecule-1, soluble intercellular adhesion molecule-1) were determined in controls, HbSS (n = 35) and HbSC (n = 23) patients. In the asymptomatic phase, serum Ang-2 (P < 0.001), EPO (P < 0.001) and sTIE2 (P = 0.03) were elevated in patients. During painful crises, increased Ang-2 (P < 0.001) and PlGF (P = 0.04) occurred in HbSS and Ang-2 (P = 0.05) in HbSC patients. These results indicate a pro-angiogenic state in SCD, mainly because of elevated Ang-2 levels.

Topics: Acute Disease; Anemia, Sickle Cell; Angiogenesis Inducing Agents; Angiopoietin-1; Angiopoietin-2; Case-Control Studies; Erythropoietin; Fetal Hemoglobin; Humans; Intercellular Adhesion Molecule-1; Leukocyte Count; Neovascularization, Pathologic; Placenta Growth Factor; Pregnancy Proteins; Receptor, TIE-2; Statistics, Nonparametric; Vascular Cell Adhesion Molecule-1; Vascular Endothelial Growth Factor A

Erythropoietin is being used more widely in the management of sickle cell disease (SCD, inclusive of homozygous sickle beta, SS, and compound heterozygous sickle beta thalassemia, Sbeta0 thal), often in conjunction with hydroxyurea (HU). Herein, we summarize the published experience with erythropoietin use in SCD, in 39 patients (SS, n = 30; Sb0 thal, n = 9) who were treated between 1990 and 1996; and in 13 patients with sickle syndromes (SS, n = 12, compound heterozygous SC disease, n = 1) who were treated with erythropoietin or darbepoietin at the National Institutes of Health (NIH) since 2002. The dose range of erythropoietin for SCD in the published series, at a median of > 200 U/Kg/dose, is higher than that used in end-stage renal disease. The median duration of erythropoietin therapy was > or =3 months, with minimal reported side-effects. At the NIH, the median age of sickle syndrome patients who received erythropoietin or darbepoietin (both referred to as EPO in the NIH series) was 51 (24 to 70) years; 12/13 patients had sickle-associated pulmonary hypertension. Eleven out of the 13 patients were treated with both HU and EPO for > 4 months (median of 11 months on EPO) without complication. Of the 13 patients, five (all SS) with pulmonary hypertension were given EPO for reticulocytopenia (< 100,000/mL) on HU; 5/13 patients (all SS), with pulmonary hypertension, were given EPO and HU concurrently, in the light of an estimated glomerular filtration rate of < 80 mL/minute. Three of the 13 patients (2 SS, 1 SC) were treated with EPO for miscellaneous reasons. Hematologic responses, detailed herein, suggest that EPO therapy may allow more aggressive HU dosing in high-risk SCD patients and in the setting of mild renal insufficiency, common to the aging sickle cell population. Furthermore EPO appears to be safe in SCD, particularly when used in conjunction with HU. We outline our current therapeutic strategy for EPO use in SCD.

Topics: Anemia, Sickle Cell; Darbepoetin alfa; Drug Therapy, Combination; Erythropoietin; Hematocrit; Humans; Hydroxyurea; National Institutes of Health (U.S.); Recombinant Proteins; Treatment Outcome; United States

Topics: Anemia; Anemia, Sickle Cell; Arteriovenous Shunt, Surgical; Blood Transfusion; Chronic Disease; Darbepoetin alfa; Diabetic Nephropathies; Disease Progression; Erythropoiesis; Erythropoietin; Europe; Evidence-Based Medicine; Ferritins; Hematocrit; Hematologic Tests; Hemoglobinometry; Hemoglobins; Hemorheology; Humans; Iron; Kidney Failure, Chronic; Nutritional Physiological Phenomena; Oxidative Stress; Quality of Life; Recombinant Proteins; Red-Cell Aplasia, Pure; Renal Dialysis; Review Literature as Topic; Transferrin; Treatment Failure; Vitamin E

Sickle cell patients are characterized by stress erythropoiesis involving cytokines, growth factors, and adhesion molecules. We set out to determine whether serum soluble vascular cell adhesion molecule-1 (sVCAM-1) levels, which are inversely related to red blood cell counts in sickle cell disease (SCD), reflect erythropoietic activity in adult HbSS patients. Serum levels of sVCAM-1 were compared to erythropoietin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and soluble transferrin receptor (sTfR) levels in 29 adults with HbSS, and their respective levels were also compared to 29 race- and age-matched HbAA controls. EPO and sTfR levels were increased as compared to healthy controls, whereas IL-3 and GM-CSF were not. No significant correlation of sVCAM-1 levels could be detected with any of the measured erythropoietic markers. Patients, but not controls, with detectable IL-3 levels had lower sTfR and GM-CSF levels as compared to patients with undetectable IL-3 levels. Even though a link of sVCAM-1 to erythropoiesis could not be established, it cannot be ruled out that sVCAM-1 levels reflect the release of young red blood cells into the circulation. IL-3 and GM-CSF levels suggest that different rates of erythropoiesis may be characterized by specific cytokine profiles in SCD. Further research should focus on the potential cytokines and adhesion molecules involved in sickle cell erythropoiesis, as this may increase our understanding of sickle cell complications and may provide us with potential markers for risk assessment in sickle cell disease as well.

Topics: Adult; Anemia, Sickle Cell; Erythrocyte Count; Erythropoiesis; Erythropoietin; Granulocyte-Macrophage Colony-Stimulating Factor; Hemoglobins; Humans; Interleukin-3; Middle Aged; Receptors, Transferrin; Reticulocyte Count; Vascular Cell Adhesion Molecule-1

Sickle cell disease (SCD) results in chronic hypoxia and secondarily increased erythropoietin concentrations. Leukocytosis and activated monocytes are also observed in SCD in absence of infection or vaso-occlusion (steady state), the reasons for which are unknown. We found that erythroid cells produced placenta growth factor (PlGF), an angiogenic growth factor belonging to the vascular endothelial growth factor (VEGF) family, and its expression was induced in bone marrow CD34+ progenitor cells in the presence of erythropoietin. Furthermore, the steady state circulating PlGF levels in subjects with severe SCD (at least 3 vaso-occlusive crises [VOCs] per year) were 18.5 +/- 1.2 pg/mL (n = 9) compared with 15.5 +/- 1.2 pg/mL (n = 13) in those with mild SCD (fewer than 3 VOCs per year) and 11.3 +/- 0.7 pg/mL (n = 9) in healthy controls (P <.05), suggesting a correlation between PlGF levels and SCD severity. In addition, PlGF significantly increased mRNA levels of the proinflammatory cytochemokines interleukin-1beta, interleukin-8, monocyte chemoattractant protein-1, and VEGF in peripheral blood mononuclear cells (MNCs) of healthy subjects (n = 4; P <.05). Expression of these same cytochemokines was significantly increased in MNCs from subjects with SCD at steady state (n = 14), compared with healthy controls. Of the leukocyte subfractions, PlGF stimulated monocyte chemotaxis (P <.05, n = 3). Taken together, these data show for the first time that erythroid cells intrinsically release a factor that can directly activate monocytes to increase inflammation. The baseline inflammation seen in SCD has always been attributed to sequelae secondary to the sickling phenomenon. We show that PlGF contributes to the inflammation observed in SCD and increases the incidence of vaso-occlusive events.

Topics: Anemia, Sickle Cell; Antigens, CD34; Bone Marrow; Chemokines; Chemotaxis; Child; Child, Preschool; Cytokines; DNA; DNA-Binding Proteins; Erythroid Precursor Cells; Erythropoietin; Humans; Leukocytes; Monocytes; Placenta Growth Factor; Pregnancy Proteins; Severity of Illness Index; Statistics as Topic; Transcription Factor MTF-1; Transcription Factors; Vascular Diseases

We have studied the effects of hydroxyurea on growth and differentiation of early erythroid progenitor cells (BFU-e) from peripheral blood of sickle cell disease patients (five SS and two Hb S/beta-thalassemia) in the presence or absence of exogenous stimulating factors. When the mononuclear cells from the sickle cell disease patients were cultured at diagnosis (before hydroxyurea treatment), there was an increased number of BFU-e in relation to controls (p < 0.05, Wilcoxon test) when cells were grown in the presence or absence of 5637 conditioned medium and erythropoietin. Colonies that developed in the absence of added growth factors were considered "spontaneous". A significant difference was observed after hydroxyurea treatment in the number of BFU-e obtained in the presence and absence of stimulus, with a higher reduction in the spontaneous BFU-e number. As expected, there was an increased Hb F level in these patients when compared with their pretreatment levels. There was no correlation between spontaneous BFU-e and hemoglobin levels in all patients studied.

Topics: Anemia, Sickle Cell; Antisickling Agents; beta-Thalassemia; Blood Cell Count; Cell Differentiation; Cell Division; Cells, Cultured; Culture Media, Conditioned; Erythroid Precursor Cells; Erythropoietin; Heterozygote; Humans; Hydroxyurea; Sickle Cell Trait

Topics: Aldosterone; Anemia, Sickle Cell; beta-Thalassemia; Erythropoietin; Humans; Kidney Diseases; Kidney Function Tests; Kidney Glomerulus; Kidney Tubules, Proximal; Proteinuria

Administration of hydroxyurea in sickle cell disease is associated with a dramatic increase of HbF along with a significant clinical improvement and, occasionally, increased total hemoglobin levels. The underlying mechanisms are not yet fully elucidated.. We report the response of three patients with homozygous sickle cell disease and 10 patients with compound HbS/beta-thalassemia (four with beta(o)thal/HbS and six with beta(+)thal/HbS respectively) to hydroxyurea treatment with regards to their serum erythropoietin levels (sEpo).. Baseline sEpo levels varied from 33.0 to 284.0 IU/L and showed a significant negative correlation with the respective Hb values (P<0.007). Two to three weeks after initiation of treatment, the sEpo values started to increase and reached levels three to 31 times higher than the baseline two to three weeks later. Thereafter, in most cases the Epo values decreased and remained at intermediate levels throughout the rest of hydroxyurea administration, while in a few cases, they returned to baseline. An inappropriate increase of sEpo following treatment with various cytostatic drugs, independently of anemia induced by cytostatic agents, has already been reported in the literature. The cytostatics included cyclophosphamide, anthracyclines, cytosine arabinoside etc., but not hydroxyurea. The results described here with hydroxyurea are virtually similar, ie, they show a significant sEpo increase five to ten days post therapy with no apparent cause. Pulses of high dose Epo have been reported to promote proliferation of erythroid precursors with HbF synthesizing capacity.. Our hypothesis is that a similar phenomenon may occur here also, in the sense that peaks of endogenous Epo may promote proliferation of erythroid precursors which maintain the capacity to synthesize HbF.

Topics: Adolescent; Adult; Anemia, Sickle Cell; beta-Thalassemia; Erythroid Precursor Cells; Erythropoietin; Female; Fetal Hemoglobin; Gene Expression Regulation; Humans; Hydroxyurea; Kidney; Liver; Male; Middle Aged; Sickle Cell Trait; Time Factors

A hemoglobin F (HbF) level between eight and nine percent divides sickle cell anemia (SS) patients into two populations, according to the kinetics of circulating burst forming units-erythroid (BFU-E), long term culture-initialing cells (LTC-IC), and cytokine plasma concentrations. The SS patients with HbF levels lower than 8-9% are more anemic (LFSS patients) than those with HbF levels higher than 8-9% who have less severe anemia (HFSS patients). We report here that the level of erythropoiesis [evaluated by the levels of soluble transferin receptors (sTfR)] is not identical in these two patient populations, supporting the idea that a different set of regulatory mechanisms might be required to maintain the two levels of increased hematopoiesis. The plasma sTfR concentration was increased in all SS samples compared with controls (P < 0.002) and sTfR levels were negatively correlated with peripheral HbF%. (r = -0.574, P < 0.002). Furthermore, sTfR levels were higher in LFSS than in HFSS patients. Erythropoietin (Epo) levels were increased in the plasma of LFSS individuals (range = 34-215 ml U/ml), while the values in HFSS patients were in the normal range (3-20 ml U/ml). Furthermore, we identify here stem cell factor (SCF) and transforming growth factor-beta (TGF-beta) as regulatory factors specifically affected by the presence of SS genotype and its level of severity. The plasma concentrations of SCF and TGF-beta were increased compared with normal controls and high levels of SCF (up to 7,000 pg/ml) were detected in LFSS patients. The latter also showed increased proportion of SCF+ CD34 enriched circulating cells (49%). Low SCF in HFSS patients is associated with elevated TGF-beta, suggesting a regulatory role of the latter on either SCF release or c-kit expression in progenitor cells. Occasional elevation of granulocyte macrophage-colony stimulating factor (G-CSF), interleukin (IL)-7, and macrophage inflammatory protein (MIP)-1alpha in plasma of SS patients is not specific because no relation to HbF could be demonstrated. All plasma tested for leukemia inhibitory factor (LIF) were negative. Data presented here, complementing previously published information, supports a model in which HFSS patients achieve a balance between inhibitory (TGF-beta) and stimulatory (SCF, IL-3) factors, resulting in moderate erythropoietic response. In contrast, in LFSS patients, low levels of TGF-beta and the increased release of GM-CSF and SCF maintain the intense erythropoies

Topics: Adult; Anemia, Sickle Cell; Antigens, CD34; Cytokines; Erythrocytes; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Granulocyte Colony-Stimulating Factor; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Interleukin-3; Interleukin-7; Kinetics; Middle Aged; Receptors, Transferrin; Solubility; Stem Cell Factor; Transforming Growth Factor beta

In the management of patients requiring chronic transfusion, various parameters may be used to evaluate the degree of erythroid marrow suppression. The aim of our study was to assess which of these parameters provide the most useful assessment of erythropoiesis. We studied 27 chronically transfused patients, 19 with sickle cell disease (SS patients) and 8 with thalassemia. Thirty-one nonchronically transfused SS patients and 74 healthy children served as controls. We measured serum transferrin receptor levels, reticulocyte counts, hemoglobin (Hb) concentrations and erythropoietin levels. The serum transferrin receptor levels were very elevated in control SS patients and remained significantly elevated in those on transfusion therapy, but were normal in thalassemia patients, indicating a more complete suppression of erythropoiesis. The reticulocyte counts were elevated in all SS patients, even when on chronic transfusion, but were in the normal range in patients with thalassemia. Erythropoietin levels were elevated in patients with thalassemia and in all the SS patients. Hb levels negatively correlated with serum transferrin receptor and erythropoietin in all SS patients. In the transfused SS patients, a higher HbS level correlated with higher reticulocyte counts, transferrin receptor, and erythropoietin levels. In thalassemia patients, erythropoiesis was more completely suppressed, as reflected both by normal reticulocyte counts and near-normal transferrin receptor levels. Though the reticulocyte counts were not significantly different in the transfused SS patients, the serum transferrin receptor levels were less elevated than in SS patients not on transfusion. The serum transferrin receptor level appears to be the most useful marker of marrow erythropoietic activity in chronically transfused SS patients. We recommend that reticulocyte counts be integrated with periodic measurements of serum transferrin receptor levels.

Topics: Adolescent; Adult; Anemia, Sickle Cell; beta-Thalassemia; Child; Child, Preschool; Erythropoiesis; Erythropoietin; Female; Hemoglobins; Humans; Infant; Male; Receptors, Transferrin; Reticulocyte Count; Transfusion Reaction

The ability of circulating progenitor cells to develop erythroid colonies was studied in vitro in the presence or absence of growth factors (5637-CM and erythropoietin) in 63 patients with sickle cell disease (SCD) (36 homozygotes for hemoglobin [Hb] S, 13 double heterozygotes for Hb S and beta thalassemia, and 14 SC patients) in Southeast Brazil. In the presence of growth factors, SCD patients (all genotypes) presented significantly higher numbers of circulating burst-forming unit-erythroid (BFU-E/5 x 10(5) MNC), when compared with control subjects. However, when the progenitor cells were cultured in the absence of added stimulus, high numbers of BFU-E were observed only in the genotypes SS and S/beta thalassemia. SC patients presented a similar response to the control subjects. Moreover, there was an inverse correlation between spontaneous (without stimulus) BFU-E and Hb levels in SCD patients. These results suggest that the formation of spontaneous BFU-E observed in SCD may be due to an expanded erythropoiesis secondary to hemolysis.

Topics: Adult; Anemia, Sickle Cell; beta-Thalassemia; Brazil; Cell Differentiation; Cell Division; Colony-Forming Units Assay; Erythroid Precursor Cells; Erythropoietin; Genotype; Hemoglobin SC Disease; Humans; Recombinant Proteins; Sickle Cell Trait

Children with sickle-cell anaemia are predisposed to thrombotic strokes, the aetiology of which is unclear. We propose that erythropoietin, produced in response to chronic anaemia, is responsible for changes in platelet reactivity with a resulting increase in thromboses. This hypothesis is based on reports of enhanced aggregability of erythropoietin-driven platelets and an increased rate of thrombosis in patients receiving large doses of recombinant erythropoietin. Experiments in animals have shown that erythropoietin stimulates synthesis of platelets, that erythropoietin-driven platelets are hyper-reactive compared with age-matched control platelets, and that erythropoietin is pro-thrombotic. These data suggest that erythropoietin-dependent changes in platelet reactivity may potentiate thrombosis in sickle-cell anaemia, particularly in children who, compared with adults, have markedly higher erythropoietin concentrations and incidence of strokes.

Topics: Adult; Anemia, Sickle Cell; Animals; Case-Control Studies; Cerebrovascular Disorders; Child; Erythropoietin; Humans; Platelet Activation; Platelet Aggregation; Recombinant Proteins; Thrombosis

The purpose of this study was to determine cost of care for leg ulcers in sickle cell patients and suggest an improved modality in ulcer care.. We performed a retrospective study of a group of sickle cell disease patients with leg ulcers.. Eighteen patients with a leg ulcer (duration: mean, 53.7 months), sickle cell disease, and a mean of 20.7 years of age had various modalities of treatment with the only consistency in healing being a commercial moist-wound dressing.. There is no consistency in the treatment of the sickle cell patient with a leg ulcer. Treatment with a moist dressing had the best results.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Arginine; Bandages, Hydrocolloid; Butyrates; Colloids; Combined Modality Therapy; Cost-Benefit Analysis; Erythropoietin; Female; Hospital Costs; Humans; Leg Ulcer; Length of Stay; Male; Occlusive Dressings; Recombinant Proteins; Recurrence; Retrospective Studies; Wound Healing

Topics: Anemia, Sickle Cell; Erythrocytes; Erythropoietin; Humans; Kidney Transplantation; Theophylline; Thrombosis

Topics: Anemia, Sickle Cell; Blood Platelets; Child, Preschool; Erythropoietin; Humans; Infant; Kidney Failure, Chronic; Recombinant Proteins; Thrombosis

Topics: Adult; Anemia; Anemia, Sickle Cell; Drug Resistance; Erythropoietin; Female; Homozygote; Humans; Kidney Failure, Chronic; Kidney Transplantation; Male

Traditional reticulocyte counts provide only a partial estimate of the erythropoietic bone marrow activity and do not account for qualitative variations of reticulocyte cellular indexes and hemoglobin content in particular. We have studied a new integrated parameter, reticulocyte hemoglobin (retHb), that quantifies in grams per liter the hemoglobin contained in the circulating reticulocyte compartment and is obtained by multiplying the absolute reticulocyte count and the reticulocyte cell hemoglobin content. In 50 normal control subjects, retHb values were 1.76 +/- 0.59 g/L. The retHb values were lower in patients double heterozygous for HbS and HbC (SC disease) (3.33 +/- 1.52 g/L, n = 13) compared with homozygous HbS disease (SS) with concomitant alpha-thalassemia (5.27 +/- 1.51 g/L and 5.48 +/- 1.06 g/L for 12 patients with 3 alpha-genes and 3 patients with 2 alpha-genes, respectively) and to SS disease with no alpha-thalassemia (6.47 +/- 3.05, n = 20). The hemoglobin contained in the red blood cell pool (rbcHb) also can be calculated by subtracting retHb from the total hemoglobin. The ratio between the two pools (rbcHb/retHb, normal value 76.6 +/- 21.9, n = 50) provides a rough estimate of red blood cell survival. It was 9.8 +/- 4.1 in SS disease, 16.2 +/- 10.1 and 14.7 +/- 5.0 in SS disease with 3 and 2 normal alpha-genes, respectively, and 36.6 +/- 17.8 in SC disease with no alpha-thalassemia. We also studied retHb in patients receiving hydroxyurea therapy for SS disease, intravenous or oral iron for iron deficiency, or recombinant human erythropoietin (r-HuEPO) therapy. All these conditions are characterized by changes in reticulocyte counts and marked variations in reticulocyte cellular hemoglobin contents, which can be integrated into the retHb parameter. Measurement of retHb and the rbcHb/retHb ratio may provide an estimate of the reduction in red blood cell survival and the severity of hemolysis in various anemias and allow more precise monitoring of the response to hydroxyurea, iron, r-HuEPO, or other therapies.

Topics: Administration, Oral; Anemia, Iron-Deficiency; Anemia, Sickle Cell; Antisickling Agents; Erythropoiesis; Erythropoietin; Hematology; Hemoglobins; Humans; Hydroxyurea; Injections, Intravenous; Iron; Recombinant Proteins; Reference Values; Reticulocyte Count; Reticulocytes

Topics: Anemia, Sickle Cell; Antisickling Agents; Erythropoietin; Female; Hemoglobins; Humans; Hydroxyurea; Pain

Topics: Adult; Anemia, Sickle Cell; Cell Adhesion; Chronic Disease; Endothelium, Vascular; Erythrocytes; Erythropoietin; Female; Hemoglobins; Humans; Hydroxyurea; Microcirculation; Pain; Pain Management

Hydroxyurea (HU) and recombinant human erythropoietin (rHuEpo) have been used in several studies to elevate Hb F level in sickle cell disease (SCD) patients and hence to ameliorate the clinical presentations of the disease. The treatment protocol and doses have varied in the different studies. We studied the effects of HU+rHuEpo combination therapy in sickle cell anaemia (SCA patients) to investigate the Hb F manipulation and hence treatment of SCA. Six patients with severe SCA were selected for treatment with HU (20-25 mg/kg body weight) and rHuEpo (400-800 U/kg body weight) combination therapy for 4 weeks followed by HU (20-25 mg/kg body weight) maintenance therapy for 6 months to 1 year. Iron and folic acid were administered during HU+rHuEpo treatment. Signs, symptoms and complications were recorded to obtain the severity index. Only patients with a severity index > or = 6 were included in the study. Haematological and biochemical parameter values, Hb A2, Hb F, Hb F distribution, Hb F cells, bilirubin level and reticulocyte count were assessed at least on 2-3 occasions prior to initiation of the therapy protocol to establish baseline values. During the treatment period, the clinical presentations were monitored and the estimation of the laboratory parameters was carried out every 4-8 weeks. The results of these parameters during HU and rHuEpo combination therapy and HU maintenance therapy were compared with baseline values using paired t test. The elevation in the level of Hb F, Hb F cells, total haemoglobin, red cell count and MCV were significant (p < 0.005), while reticulocyte count and total bilirubin were significantly decreased (p < 0.05). Each patient showed an individual pattern of Hb F elevation. The increase in Hb F level was correlated with the haematological and biochemical parameters using the General Linear Model Programme of Statistical Analysis System. In general, the clinical presentation improved as Hb F level increased in each patient. In addition, the positive correlation with the haematological parameters and negative correlation with reticulocytes and total bilirubin confirmed the beneficial effect of elevated Hb F level on reducing red cell haemolysis. No correlation could be demonstrated between the pretreatment Hb F level and the increase in Hb F during the treatment period. Daily doses of HU with a single intravenous rHuEpo and iron supplementation elevate Hb F and Hb F cells in SCA patients. The Hb F level can be maintained h

Topics: Adult; Anemia, Sickle Cell; Bilirubin; Blood Cell Count; Drug Evaluation; Drug Synergism; Erythropoietin; Female; Fetal Hemoglobin; Gene Expression Regulation; Humans; Hydroxyurea; Immunologic Factors; Male; Recombinant Proteins; Reticulocytes

Butyrate, a four-carbon fatty acid, and its two-carbon metabolic product, acetate, are inducers of gamma-globin synthesis. To test whether other short-chain fatty acids share this property, we first examined whether propionic acid, a three-carbon fatty acid that is not catabolized to acetate, induces gamma-globin expression. Sodium propionate increased the frequency of fetal hemoglobin containing erythroblasts and the gamma/gamma + beta mRNA ratios in adult erythroid cell cultures and F reticulocyte production in a nonanemic juvenile baboon. Short-chain fatty acids containing five (pentanoic), six (hexanoic), seven (heptanoic), eight (octanoic), and nine (nonanoic) carbons induced gamma-globin expression (as measured by increase in gamma-positive erythroblasts and gamma/gamma + beta mRNA ratios) in adult erythroid burst-forming unit cultures. There was a clear-cut relationship between the concentration of fatty acids in culture and the degree of induction of gamma-globin expression. Three-, four-, and five-carbon fatty acids were better inducers of gamma globin in culture as compared with six- to nine-carbon fatty acids. These results suggest that all short-chain fatty acids share the property of gamma-globin gene inducibility. The fact that valproic acid, a derivative of pentanoic acid, also induces gamma-globin expression suggests that short-chain fatty acid derivatives that are already approved for human use may possess the property of gamma-globin inducibility and may be of therapeutic relevance to the beta-chain hemoglobinopathies.

Topics: Adult; Anemia, Sickle Cell; Animals; Anticonvulsants; Butyrates; Butyric Acid; Cells, Cultured; Epilepsy; Erythroid Precursor Cells; Erythropoietin; Fatty Acids, Volatile; Fetal Hemoglobin; Gene Expression Regulation; Globins; Hemoglobinopathies; Humans; Papio; Pentanoic Acids; Propionates; Reticulocytes; RNA, Messenger; Structure-Activity Relationship; Valproic Acid

Topics: Anemia, Aplastic; Anemia, Sickle Cell; Erythropoietin; Female; gamma-Globulins; Humans; Infant

Six sickle cell/beta-thalassemia patients (3 males and 3 females) were treated with 500 U/kg body weight human recombinant erythropoietin (h-rEPO) along with 300 mg/day iron sulfate in two phases, for a period of 90 days. Fetal hemoglobin (HbF) was assayed every 2 weeks and the gamma-chain ratio at three successive intervals during the treatment. All patients showed a moderate to high increase in their HbF values (1.25- to 12-fold). The gamma-chain ratio, as determined by high performance liquid chromatography was found to be unaffected by the HbF increase. Two patients with the newborn gamma-chain ratio, responded faster to the h-rEPO treatment and achieved higher HbF values than the rest of the group. The h-rEPO treatment was very well tolerated and had a positive effect on the general clinical condition of all the patients.

Topics: Adolescent; Adult; Anemia, Sickle Cell; beta-Thalassemia; Child; Drug Evaluation; Drug Therapy, Combination; Erythrocyte Indices; Erythropoietin; Female; Ferrous Compounds; Fetal Hemoglobin; Globins; Humans; Male; Middle Aged; Recombinant Proteins; Stimulation, Chemical; Time Factors

Hydroxyurea increases the production of fetal hemoglobin in patients with sickle cell anemia, inhibiting the polymerization of hemoglobin S and potentially improving vaso-occlusive manifestations and hemolysis. Recombinant erythropoietin increases the number of reticulocytes containing fetal hemoglobin in laboratory animals and in humans. We studied whether hydroxyurea and erythropoietin might have a potentiating effect on the production of fetal hemoglobin in patients with sickle cell disease.. We treated four patients who were receiving hydroxyurea for sickle cell disease (three who were homozygous for sickle cell anemia and one with sickle beta zero-thalassemia) with escalating doses of intravenous erythropoietin for seven weeks, along with oral iron sulfate. Doses of hydroxyurea on four consecutive days were alternated with doses of erythropoietin on three consecutive days.. There was a 28 percent increase in the number of reticulocytes containing fetal hemoglobin and a 48 percent increase in the percentage of fetal hemoglobin, as compared with the maximal values obtained with hydroxyurea alone. The percentage of erythrocytes containing fetal hemoglobin (F cells) increased from 64 to 78 percent. As compared with hydroxyurea alone, treatment with hydroxyurea and erythropoietin decreased the mean (+/- SD) serum indirect bilirubin level from 0.8 +/- 0.2 to 0.5 +/- 0.1 mg per deciliter (13.3 +/- 2.9 to 8.9 +/- 2.2 mumol per liter) (P = 0.02), suggesting a further decrease in hemolysis. Red-cell filterability improved.. Intravenous recombinant erythropoietin with iron supplementation alternating with hydroxyurea elevates fetal-hemoglobin and F-cell levels more than hydroxyurea alone. Such increases decrease intracellular polymerization of hemoglobin S and improve the overall rheologic characteristics of erythrocytes. A reduced dosage of hydroxyurea alternating with erythropoietin may prove less myelotoxic than hydroxyurea given daily or in pulsed-dose regimens. It may also increase levels of fetal hemoglobin in patients with sickle cell disease who have not been helped by hydroxyurea alone.

Topics: Adult; Anemia, Sickle Cell; beta-Thalassemia; Drug Synergism; Drug Therapy, Combination; Erythrocyte Count; Erythrocyte Indices; Erythropoietin; Ferrous Compounds; Fetal Hemoglobin; Humans; Hydroxyurea; Male; Recombinant Proteins; Reticulocytes

A two-phase liquid-culture system was used to substantially amplify and differentiate erythroblasts, starting with mononuclear cells from the blood of normal adults, newborn infants, and patients with sickle cell anemia. After the first 7 days (phase 1), in medium plus fetal bovine serum (FBS) alone, or in combination with stem cell factor (SCF) or conditioned medium (CM), the cell number was unchanged, and the cells all looked like lymphocytes. These cells were then diluted into medium with erythropoietin (Ep) alone, with Ep and either SCF or CM, or in methylcellulose with the same factors (phase 2). After 14 days in liquid phase 2 with SCF and Ep, the cell numbers increased an average of 30-fold in the sickle, 24-fold in the newborn, and 4-fold in the normal adult cultures; almost all the cells were erythroblasts and erythrocytes. SCF in phase 1 increased the number of late progenitors (CFU-E) assayed in methylcellulose, with the largest number in sickle, followed by newborn cultures and then adult cultures. We conclude that erythroid progenitor cells survive for at least 7 days without Ep (but with FBS). Progenitor cells are amplified, particularly with SCF. Later in culture, SCF with Ep increases the final number of differentiated erythroid cells. Both the early and the late effects of SCF are most effective in sickle, followed by newborn cultures and then adult cultures.

Topics: Adult; Anemia, Sickle Cell; Cell Differentiation; Cell Division; Cells, Cultured; Colony-Forming Units Assay; Culture Media, Conditioned; Erythroblasts; Erythropoiesis; Erythropoietin; Female; Hematopoietic Cell Growth Factors; Humans; Infant, Newborn; Leukocytes; Male; Reference Values; Stem Cell Factor; Stem Cells; Tumor Cells, Cultured; Urinary Bladder Neoplasms

The development of end-stage renal disease (ESRD) in patients with sickle-cell anaemia results in increased transfusion dependence, increasing the risk of iron overload. Correction of anaemia with recombinant human erythropoietin (rHuEpo) in dialysis patients might also result in stimulation of haemoglobin F production, which protects against sickling, although very high doses were required to achieve this effect in non-uraemic animals. rHuEpo was administered to three transfusion-dependent patients with ESRD and homozygous sickle-cell disease (initial dose 100 U/kg twice weekly, increasing to 125 U/kg at 6 weeks, and to 150 U/kg at 9 weeks in two patients). This resulted in reticulocytosis and increased circulating erythroid blast-forming units. Total haemoglobin was predominantly HbA (i.e. transfused blood) at the start of the study, reflecting transfusion dependence, but after 3 months' treatment was between 60 and 94% HbS. No sickling crises occurred. Haemoglobin F remained at less than 3% of total haemoglobin. One patient was withdrawn at 10 weeks with CAPD peritonitis. The other two patients completed 12 weeks' treatment without transfusion but final Hb concentrations were 4.5 and 5.5 g/dl. Whether larger doses of rHuEpo will be more successful in managing such patients remains unclear. No effect on HbF production can be expected.

Topics: Adult; Anemia, Sickle Cell; Blood Transfusion; Erythropoiesis; Erythropoietin; Hemoglobins; Humans; Kidney Failure, Chronic; Middle Aged; Recombinant Proteins

Blood erythroid progenitors (BFU-E) from patients with sickle and thalassemic syndromes were compared with those from normal individuals. The day of maximal colony formation in methyl cellulose was slightly later in the cultures from the patients with hemoglobinopathies than in the normal cultures. The number of colonies/100,000 mononuclear cells was similar in all cultures on day 13, but was higher in the hemoglobinopathy cultures on the day of maximal growth. The number of BFU-E/mL of blood was significantly higher than normal at all times in both sickle cell anemia and thalassemia. The proportional synthesis of gamma globin was twice normal in all sickle cultures, and 4 times normal in those from beta+-thalassemia. Hemin and interleukin-3 increased the numbers of erythroid colonies in all cultures, but did not consistently alter the globin synthesis patterns. Each progenitor population has a unique pattern in terms of time course, number of BFU-E, and level of gamma globin synthesis. These features indicate distinct types of BFU-E, or differences in accessory cells, or both, which distinguish blood-borne erythropoiesis in normals and those with hemoglobinopathies.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Cell Count; Child; Child, Preschool; Colony-Forming Units Assay; Erythroid Precursor Cells; Erythropoiesis; Erythropoietin; Female; Globins; Hemin; Humans; Interleukin-3; Male; Middle Aged; Reference Values; Sensitivity and Specificity; Thalassemia

Although recombinant human erythropoietin (rHuEPO) has only been approved for clinical use since 1989, its beneficial effects in the treatment of anemia in patients with chronic renal failure has been clearly demonstrated. Bolstered by this success, clinical investigators are now turning to other types of anemia that might benefit from such therapy. Part II of this article will continue to discuss some of the potential areas of clinical application for rHuEPO. Part I was published last month in NN&I.

Topics: Anemia; Anemia, Sickle Cell; Erythropoietin; Female; Humans; Male; Menstruation Disturbances; Physical Endurance; Pregnancy; Puerperal Disorders; Recombinant Proteins

Topics: Adult; Anemia, Sickle Cell; Blood Transfusion; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Recombinant Proteins

Topics: Adult; Anemia, Sickle Cell; Christianity; Erythropoietin; Female; Femur Head Necrosis; Humans; Intraoperative Complications

A 23-year-old man with severe sickle cell disease and a chronic non-healing left leg ulcer was entered into a study in which he received hydroxyurea (HU) and recombinant human erythropoietin (r-HuEPO) in order to modify the severity of his disease. HU 20 mg/kg/day effectively prevented vaso-occlusive crises and improved hematological parameters, but the chronic leg ulcer and chronic mild bone pains remained. Six months later, r-HuEPO 600-800 IU/kg subcutaneously was added at weekly intervals. This led to a rapid and complete healing of the chronic leg ulcer, further improvement in hematological parameters and relief from chronic pains. We conclude that treatment with r-HuEPO may provide an effective therapy for chronic leg ulcers in patients with sickle cell disease.

Topics: Adult; Anemia, Sickle Cell; Chronic Disease; Erythropoietin; Humans; Leg Ulcer; Male; Recombinant Proteins

Erythroid progenitors circulating in peripheral blood and their response to erythropoietin (EPO), interleukin-3 (IL3), and phytohemagglutinin-stimulated, lymphocyte-conditioned medium (PHALCM) were assessed in sickle cell anemia (SCA) patients and controls. SCA patients have significantly higher numbers of circulating burst-forming unit-erythroid (BFU-E) compared with controls (mean +/- SEM, 940.27 +/- 129.11 per ml and 86.56 +/- 19.74 per ml, respectively; P less than 0.0001). At low doses of EPO, BFU-E-derived colonies were significantly increased in SCA patients compared with controls (each P less than 0.05). The EPO dose required to produce 50% of maximum colony numbers was 47 times greater in control subjects than in SCA patients. Moreover, in 11 of 17 patients with SCA, spontaneous BFU-E-derived colonies were formed without added erythropoietin. This phenomenon was not observed in control subjects (P = 0.035). PHALCM developed from mononuclear cells of SCA patients had significantly greater stimulatory effect than did that derived from controls regardless of the source of target cells (each P less than 0.05). A two-step study of IL3 sensitivity of erythroid progenitors was conducted. First, in a liquid culture system, circulating erythroid progenitors of SCA patients and controls were incubated in the presence of varying doses of IL3. During a second step, CFU-E-like colonies were observed in methylcellulose cultures of these cells. The mean numbers of colony-forming unit-erythroid (CFU-E)-like colonies was significantly higher in SCA patients compared with control subjects at low doses of IL3 (each P less than 0.02). The increased response of erythroid progenitors to IL3 and the increased production of hemopoietic growth factors (IL3 or non-IL3) contribute to the hemopoietic response in SCA patients. These mechanisms and increased sensitivity of the BFU-E to EPO may explain lower than expected EPO levels in SCA patients.

Topics: Anemia, Sickle Cell; Cell Division; Culture Media; Erythroid Precursor Cells; Erythropoietin; Humans; Interleukin-3; Lymphocyte Activation

Hydroxyurea increases the production of fetal hemoglobin (hemoglobin F) in patients with sickle cell anemia and therefore has the potential for alleviating both the hemolytic and vaso-occlusive manifestations of the disease. There is preliminary evidence that recombinant human erythropoietin may also increase hemoglobin F production.. We treated five patients with sickle cell disease with escalating doses of intravenous erythropoietin for eight weeks. Three of these patients were subsequently treated with daily doses of oral hydroxyurea. After the optimal dose was determined, erythropoietin was then given along with hydroxyurea for four weeks. Treatment with erythropoietin, either alone or in combination with hydroxyurea, had no significant effect on the percentage of hemoglobin F-containing reticulocytes (F reticulocytes) or red cells (F cells). In contrast, hydroxyurea treatment was associated with a 3-to-25-fold increase in F reticulocytes, a 1.6-to-7-fold increase in F cells, and a 2.3-to-16-fold increase in the percentage of hemoglobin F. In all three patients given hydroxyurea, treatment with this drug was associated with reduced hemolysis, shown by decreases in serum bilirubin and lactic dehydrogenase and prolongation of red-cell survival. Hydroxyurea treatment also resulted in a decrease in the percentage of irreversibly sickled cells and sickling at partial oxygen saturation, an increase in oxygen affinity and total red-cell cation content, and a reduction in potassium-chloride cotransport. All three patients had a decrease in the number of pain crises.. This study confirms that hydroxyurea therapy increases hemoglobin F production and provides objective evidence that hydroxyurea reduces the rate of hemolysis and intracellular polymerization of hemoglobin S. In contrast, recombinant human erythropoietin, whether alone or in combination with hydroxyurea, offers no measurable benefit.

Topics: Administration, Oral; Anemia, Sickle Cell; Drug Administration Schedule; Drug Evaluation; Drug Therapy, Combination; Erythrocytes; Erythropoietin; Fetal Hemoglobin; Hemoglobin, Sickle; Hemolysis; Humans; Hydroxyurea; Recombinant Proteins; Reticulocytes

Topics: Anemia, Sickle Cell; Drug Therapy, Combination; Erythropoietin; Humans; Hydroxyurea

Topics: Anemia, Sickle Cell; Erythropoietin; Fetal Hemoglobin; Humans; Recombinant Proteins

Topics: Anemia, Sickle Cell; Animals; Erythropoietin; Fetal Hemoglobin; Humans; Papio; Recombinant Proteins

Topics: Adult; Anemia, Sickle Cell; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Humans; Male; Middle Aged; Recombinant Proteins; Reticulocytes

Circulating 14-day erythroid progenitors (BFU-E) from sickle cell anemia (SS) patients were studied in culture to determine their frequency and their sensitivity to erythropoietin (Epo). Increased numbers of circulating BFU-E were found in half of the patients studied, whereas the remainder had a normal count. Patients with high circulating BFU-E counts had lower fetal hemoglobin (HbF) percentages (congruent to 4.5%) than patients with low circulating BFU-E counts (HbF congruent to 13%). This difference was highly significant (p less than 0.0001). In addition, SS circulating BFU-E expressed increased sensitivity to Epo due, at least partially, to an increased production of burst-promoting activity-like factor(s) generated by light-density mononuclear cells. These findings emphasize the possible role of the HbF level (and the extent of sickling) in BFU-E regulation under the continuous hemopoietic stress of SS disease.

Topics: Adult; Anemia, Sickle Cell; Colony-Forming Units Assay; Dose-Response Relationship, Drug; Erythrocyte Aggregation; Erythrocytes; Erythropoietin; Female; Humans; Male; Middle Aged; Time Factors

We have examined the possibility that permanent "stress" hemopoiesis in sickle cell anemia (SS) patients leads to the modification of the behavior of circulating 14 day erythroid progenitor cells (BFU-E). In these patients we find that peripheral blood BFU-E are increased in number and have high sensitivity to erythropoietin (Epo). Maximal number of BFU-E are generated from peripheral blood of SS patients at 0.3-0.75 Epo/ml of culture compared to 1.5-2.0 U Epo/ml of culture in normals. Peripheral blood adherent cells depletion leads to the shift of Epo dose response curve, so that the Epo sensitivity of BFU-E significantly decreases. This result suggests that apparent Epo hypersensitivity reflects, in fact, an increased production of a burst promoting activity (BPA) by SS peripheral blood light density adherent (PB-LDA) cells. Experiments with conditioned medium by SS PB-LDA cells confirmed this interpretation. When peripheral blood light density non-adherent (PB-LDNA) cells of SS patients or normal individuals were plated in the presence of various concentrations of SS PB-LD cells conditioned medium and constant amounts of Epo, a dose dependent increase of the number of BFU-E was observed. When the same target cells were plated in the presence of PB-LD cells conditioned medium from normal individuals, such effect does not occur. We conclude that increased BPA production may play a role in the erythropoietic regulation during constant hemopoietic stress in sickle cell anemia and might partially explain the lower than expected Epo levels in these patients.

Topics: Anemia, Sickle Cell; Cells, Cultured; Dose-Response Relationship, Drug; Erythropoiesis; Erythropoietin; Hematopoietic Stem Cells; Humans; Methylcellulose

Stimulating the production of fetal hemoglobin may benefit patients with sickle cell anemia by inhibiting sickling. We gave pulsed treatments with high doses of recombinant human erythropoietin to baboons in order to test the hypothesis that the resultant rapid erythroid regeneration would stimulate F cells--i.e., cells that contain fetal hemoglobin. In normal animals, this treatment caused sharp increments in F-reticulocyte levels, which rose from 1 to 2 percent before treatment to 40 to 50 percent afterward. In two animals with chronic anemia and high levels of endogenous erythropoietin, recombinant human erythropoietin induced further increments in F-reticulocyte levels, which rose in one animal from 6 to 8 percent before treatment to 23 percent after treatment, and in the other from 20 percent before to 50 percent afterward. The time course of F-reticulocyte stimulation suggested that these cells were the products of mobilized early erythroid progenitors. These results raise the possibility that pulses of erythropoietin could be used to stimulate F-cell formation in patients with sickle cell disease.

Topics: Anemia, Hypochromic; Anemia, Sickle Cell; Animals; Erythrocyte Count; Erythropoietin; Fetal Hemoglobin; Humans; Papio; Recombinant Proteins; Reticulocytes; Stimulation, Chemical

Erythropoietin titers when related to the hematocrit percentage and measured by bioassay in 33 normal volunteers and in 61 patients with anemias not complicated by renal or chronic disease were found to overlap with titers measured by radioimmunoassay in 20 normals and 28 patients with similar anemias. Erythropoietin titers measured by radioimmunoassay in 34 patients with rheumatoid arthritis, 25 patients with sickle cell anemia (58 separate samples), and 28 patients with erythroid hypoplasia caused by hematologic malignancies were compared with those in the control group of patients with uncomplicated anemias and found not to differ significantly from titers in this group. Erythropoietin titers measured by bioassay in 12 patients with aplastic anemia also fell within the range of those in the control group. Consequently, erythropoietin titers in these anemias appear to be determined primarily by the degree of anemia and not by any specific effect of these illnesses on the production of erythropoietin.

Topics: Anemia; Anemia, Aplastic; Anemia, Sickle Cell; Arthritis, Rheumatoid; Biological Assay; Erythropoietin; Female; Hematologic Diseases; Humans; Male; Radioimmunoassay; Red-Cell Aplasia, Pure

Topics: Anemia, Sickle Cell; Erythrocyte Deformability; Erythrocytes; Erythropoietin; Hematocrit; Hemoglobins; Humans; Infarction; Oxygen; Pain

We have studied serum immunoreactive erythropoietin (SIE) levels in 28 patients with sickle cell anemia (SCA) without renal insufficiency and in 17 patients with nonhemoglobinopathy anemias of comparable severity using a sensitive radioimmunoassay procedure. An exponential relationship between SIE level and degree of anemia was noted in all patients. However, in nonhemoglobinopathy anemia, a sharp rise in the SIE level occurred as hemoglobin (Hb) levels fell below about 12 g/dL, whereas in sickle cell patients the increase was not marked until hemoglobin fell to about 9 g/dL. The response was more blunted in older SCA patients than in younger ones. A linear regression model relating SIE level to Hb level, presence/absence of SCA, and age explained 63% of the variation in SIE. We conclude that the serum erythropoietin levels in SCA increased at a lower hemoglobin concentration and are of a lower magnitude than that of the other anemias.

Topics: Adolescent; Adult; Age Factors; Anemia, Sickle Cell; Child; Child, Preschool; Erythropoietin; Hemoglobins; Humans; Infant; Kidney Diseases

The effects of prostaglandin E2 (PGE2) in association with erythropoietin on the synthesis of fetal and adult hemoglobin in peripheral blood-derived erythroid burst colonies from normal adults and from patients with sickle cell anemia were investigated. The synthesized hemoglobin at the end of 8, 14 or 18 days in culture was separated by DEAE-cellulose chromatography of 35S-methionine labelled hemoglobin. Quantitative estimation of the synthesized hemoglobin phenotypes, for the three indicated culture periods, showed preferential synthesis of Hb F in addition to an overall increase in hemoglobin synthesis in PGE2 treated colonies. Furthermore, the reactivation of fetal hemoglobin production by PGE2 was more pronounced when the adherent cells were included in the culture dishes. These results indicate that the addition of PGE2 to culture dishes presumably constitutes an environmental change to promote the functional changes seen in the blood erythroid bursts in terms of Hb synthesis and switching.

Topics: Adult; Anemia, Sickle Cell; Cells, Cultured; Child; Dinoprostone; Drug Synergism; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Hemoglobins; Humans; Middle Aged; Prostaglandins E

The erythropoietin response to anaemia was compared in 30 children with haemolytic anaemia and in 5 children with Fanconi's hypoproliferative anaemia. Serum erythropoietin was measured by radioimmunoassay. In children with haemolytic anaemia the serum erythropoietin concentration increased exponentially with decreasing haematocrit values (r = 0.74; p less than 0.001). Serum erythropoietin levels also correlated with reticulocyte counts (r = 0.62; p less than 0.001). Children with Fanconi's hypoproliferative anaemia had considerably higher serum erythropoietin levels than children with haemolysis for the same degree of anaemia. These data indicate that erythropoietin production in Fanconi's anaemia may be dependent on other factors in addition to the degree of anaemia and relative hypoxaemia.

Topics: Adolescent; Anemia, Aplastic; Anemia, Sickle Cell; Cell Count; Child; Child, Preschool; Erythropoietin; Fanconi Anemia; Female; Hematocrit; Humans; Male; Radioimmunoassay; Reticulocytes; Sickle Cell Trait

To investigate the cellular events that accompany erythroid hyperplasia, we studied several effects of erythropoietin (Epo) on marrow CFU-E in sickle cell anemia (SCA). We measured CFU-E number, CFU-E growth as a function both of Epo exposure time and of Epo concentration, and suppression of Epo-induced CFU-E formation by anti-Epo antiserum. With 0.5 U Epo/ml, the number of CFU-E was elevated in SCA (1,087 +/- 520) compared to normal (430 +/- 130). CFU-E were formed even when Epo was immediately neutralized by a 1/150 dilution of anti-Epo. After 40 hr of Epo exposure, only 2% of total CFU-E were expressed in normal marrow, whereas 12%-40% of CFU-E were expressed in SCA. Inhibition of CFU-E growth required at least 1/50 dilution of anti-Epo in SCA and a 1/300 dilution in normal marrow. In contrast to normal, a small number (5%-20%) of CFU-E were expressed in the absence of added Epo in SCA, and this pool required a 1/150 dilution of anti-Epo for inhibition. The Epo dose-response curve in SCA revealed a peak in colony formation around 0.1 U Epo/ml and 0.5 U Epo/ml, whereas only one peak at 0.5 U Epo/ml was seen in normals. These data strongly suggest that, in response to the demands of chronic erythroid hyperplasia in SCA, a pool of CFU-E is present characterized by increased in vitro sensitivity to Epo.

Topics: Anemia, Sickle Cell; Animals; Bone Marrow; Colony-Forming Units Assay; Dose-Response Relationship, Drug; Erythropoiesis; Erythropoietin; Hematopoietic Stem Cells; Humans; Hyperplasia; Immune Sera; In Vitro Techniques; Rabbits

The role of oxygen therapy in sickle-cell anemia is not established, and its effects on erythropoiesis and on the rheologic properties of sickled erythrocytes are controversial. When three patients with sickle-cell anemia who were not in crisis or infected breathed oxygen at a rate of 5 liters per minute continuously through nasal prongs for five days, there was a rapid decline in erythropoietin levels that had initially been elevated, a delayed fall in the number of reticulocytes, and a fall in the number of irreversibly sickled cells, which, in two of the subjects, preceded the suppression of reticulocytosis. After cessation of oxygen therapy, erythropoietin levels and the number of irreversibly sickled cells increased promptly, followed by an increase in the number of reticulocytes. Calculated erythropoietin half-lives were 1.51 to 2.92 hours, and clearances were 43 to 84 ml per minute during oxygen administration. These are normal values. In two subjects, the number of irreversibly sickled cells rose to exceed base-line values after oxygen therapy was discontinued, and both subjects had acute painful episodes at this time. We conclude that in patients with sickle-cell anemia, substantial changes in erythropoiesis and in the rheologic properties of blood occur in association with oxygen inhalation and that when oxygen therapy is administered to such patients, it should be given intermittently rather than continuously.

Topics: Anemia, Sickle Cell; Erythrocyte Count; Erythrocytes; Erythrocytes, Abnormal; Erythropoiesis; Erythropoietin; Humans; Kinetics; Leukocyte Count; Oxygen Inhalation Therapy; Reticulocytes

The relation between haemoglobin concentration, creatinine clearance, and the serum concentration of erythropoiesis-stimulating factor were assessed in 31 patients with homozygous sickle-cell disease. Haemoglobin concentrations fell significantly with decreasing creatinine clearance (r = 0.58, p less than 0.001) and were positively correlated with the concentration of erythropoiesis-stimulating factor (r = 0.65, p less than 0.001). These observations suggest that erythropoietin concentration is the factor limiting production of red cells in sickle-cell disease with renal insufficiency and have implications for treatment.

Topics: Adolescent; Adult; Aged; Anemia, Sickle Cell; Creatinine; Erythropoietin; Female; Hemoglobins; Humans; Kidney; Male; Middle Aged

Erythropoietin responsible for the hormonal regulation of red blood cell production. Its formation is largely controlled by the kidneys. A number of assay methods for erythropoietin are available. Asymptomatic patients with sickle cell disease have elevated erythropoietin levels, as expected with chronic hemolysis. When complicated by chronic renal failure, erythropoietin levels do not rise appropriately. Chronic infection has not been studied, but the erythropoietin response in acute infection does not seem to conform to a pattern. Aplastic crises are characterized by very high levels of erythropoietin, suggesting bone marrow suppression, but events that trigger the crises remain obscure. In vaso-occlusive crises, there is also some suggestion of mild and transient lack of bone marrow response. Patients with sickle cell disease, with their chronic high erythropoietin anemia and susceptibility to altered states, are uniquely suited for investigating the physiology of erythropoietin, especially under the constraints of present assay methods.

Topics: Anemia, Sickle Cell; Erythropoietin; Hematopoietic Stem Cells; Humans; Infections; Kidney; Kidney Failure, Chronic

Bone marrow cells, peripheral blood lymphocytes, and sera from patients with sickle-cell anemia in hypoproliferative crisis were studied in the plasma clot culture system in the presence or absence of erythropoietin (Epo). Bone marrow cells from five patients demonstrated a marked ability to form erythroid colonies in the presence of Epo. These studies also suggested that bone marrow cells from some patients may have an increased sensitivity to Epo. The most outstanding observation in the present study was the marked erythroid colony inhibition by serum taken from one patient during crisis. Serum taken from the same patient two months after hypoproliferative crisis had no suppressive effect on erythroid colony formation. Lymphocytes taken from three patients in crisis had a stimulatory effect on erythroid colony formation when included in culture. The conclusion is that the defect of erythropoiesis in sickle-cell anemia during hypoproliferative crisis is not due to the absence of erythroid precursor cells or to the presence of suppressor lymphocytes, but may in some cases be associated with a circulating inhibitor of erythroid maturation.

Topics: Anemia, Sickle Cell; Bone Marrow Cells; Cells, Cultured; Colony-Forming Units Assay; Erythrocytes, Abnormal; Erythropoiesis; Erythropoietin; Humans; Lymphocytes

Erythropoiesis was evaluated in 37 patients with sickle cell anaemia, 26 of them children under 12 years of age. Mean haemoglobin, haematocrit, reticulocyte, and erythropoietin levels were similar for 11 who were asymptomatic, 11 with infections, and 12 in vaso-occlusive crisis. Mean haemoglobin, haematocrit, and reticulocyte values were significantly lower and the mean erythropoietin level significantly higher for three patients in aplastic crisis. Reticulocyte counts reflected erythropoietic activity during the asymptomatic state but were variable during infection and crisis. No erythropoietic inhibitory activity was found in any of the four clinical states. It has been suggested that erythropoietin production decreases during infection. Patients in this study responded appropriately to stress, showing no decrease in erythropoietic activity during acute infection or crisis.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Blood Cell Count; Child; Child, Preschool; Erythropoiesis; Erythropoietin; Female; Hematocrit; Hemoglobins; Humans; Infant; Infections; Male; Reticulocytes; Thrombosis; Vascular Diseases

Topics: Anemia, Sickle Cell; Bone Marrow; Bone Marrow Cells; Colony-Forming Units Assay; Dose-Response Relationship, Drug; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Globins; Humans; Male; RNA, Messenger

Seven patients with sickle cell anemia were treated with oxymetholone for at least 2 mo. Markedly increased basal rates of hemolysis and erythropoiesis were confirmed. The urinary erythropoietin excretion was either normal or lower than expected for the red cell mass, and an expanded blood volume was due primarily to an increased plasma volume. After androgen therapy, six patients demonstrated more than a fivefold increase in urinary erythropoietin, with an increase in red cell mass ranging from 17%-75% above the control value. All showed a decline in serum iron level to the 25-75 mug/100 ml range within 4 wk after the start of therapy. Less marked changes followed lower oxymetholone doses. Reversible hepatic toxicity, with a serum bilirubin concentration exceeding 50 mg/100 ml, occurred in one patient. Androgenic hormone therapy may be useful for selected adult patients with sickle cell disease when severe anemia contributes to disease morbidity.

Topics: Adolescent; Adult; Androgens; Anemia, Sickle Cell; Bilirubin; Blood Volume; Cell Survival; Chromium Radioisotopes; Erythrocytes; Erythropoiesis; Erythropoietin; Female; Hematocrit; Hemolysis; Humans; Iron; Iron Radioisotopes; Liver; Liver Function Tests; Male; Middle Aged; Oxymetholone

Topics: Anemia, Sickle Cell; Bone Marrow; Bone Marrow Cells; Cells, Cultured; Erythropoietin; Fetal Blood; Hemoglobins; Humans; Infant, Newborn

Topics: Adolescent; Adult; Aged; Anemia, Aplastic; Anemia, Hemolytic; Anemia, Sickle Cell; Bone Marrow Diseases; Creatinine; Erythropoietin; Female; Hematocrit; Hemolysis; Humans; Iron; Leukemia; Lymphoma; Male; Middle Aged; Multiple Myeloma; Sex Factors

Topics: Anemia, Hemolytic; Anemia, Hemolytic, Autoimmune; Anemia, Myelophthisic; Anemia, Sickle Cell; Bone Marrow; Erythropoietin; Heart Diseases; Hematocrit; Humans; Hypoxia; Kidney Diseases; Reticulocytes; Spherocytosis, Hereditary

Close linkage of mutually exclusive genes occurs in the non-alpha chain hemoglobin genes and in the immunoglobulin genes of man and other mammals. The expression of one gene in the cluster precludes the expression of any other linked gene. A simple, testable theory of gene selection called "looping-out excision"which was designed only to explain this mutual exclusivity in the hemoglobin system is described. The theory is closely concordant with a wide range of previously unexplained findings concerning hematopoiesis- including the developmental changes of hemoglobins, the increases in immature or fetal forms of hemoglobin that accompany anemia, and with the distribution of adult and fetal hemoglobins among erythrocytes during normal embryogenesis and in various pathological conditions. One corollary of this theory is that erythroid tissue in the normal adult bone marrow is constantly recapitulating the developmental stages of its embryogenesis. Another corollary is that the selection from among the linked globin genes occurs independently on the two chromosomes of the diploid organism. Both of these corollaries are supported by the available data. The same theory of gene selection is also remarkably consistent with known data for immunoglobulin synthesis; it could explain not only the mutually exclusive activation of linked variable genes but also the splicing which occurs between genetically linked variable and constant region genes for the immunoglobulin polypeptide chains. The agreement between these two different tissues is considered to be strong evidence that the proposed mechanism is correct at least in broad outline. Evidence from the genetics of maize and of drosophila also supports this theory of somatic tissue variegation. On the basis of these comparisons, I suggest that looping-out excision probably occurs also in other tissues and may be one means of gene selection and activation in differentiating cells.

Topics: Alleles; Anemia; Anemia, Sickle Cell; Animals; Antibody-Producing Cells; Electrophoresis, Disc; Erythrocytes; Erythropoiesis; Erythropoietin; Fetal Hemoglobin; Genes; Genetic Linkage; Genetics; Genotype; Gestational Age; Hematopoietic Stem Cells; Hemoglobins; Heterozygote; Homozygote; Humans; Immunoglobulins; Models, Biological; Sheep

Topics: Anemia; Anemia, Aplastic; Anemia, Sickle Cell; Animals; Biological Assay; Breast Neoplasms; Cachexia; Erythrocytes; Erythropoiesis; Erythropoietin; Iron; Iron Isotopes; Leukemia; Lymphoma; Male; Mice; Plasma; Polycythemia; Prostatic Neoplasms

Topics: Adolescent; Anemia; Anemia, Aplastic; Anemia, Hemolytic; Anemia, Hypochromic; Anemia, Sickle Cell; Animals; Biological Assay; Blood Cell Count; Bone Marrow Examination; Child; Child, Preschool; Erythrocytes; Erythropoiesis; Erythropoietin; Female; Hemoglobinometry; Humans; Iron; Iron Isotopes; Male; Rats; Reticulocytes; Thalassemia

Topics: Anemia, Sickle Cell; Blood; Erythropoietin; Humans; Urine

Topics: Anemia; Anemia, Hemolytic; Anemia, Sickle Cell; Epoetin Alfa; Erythroblastosis, Fetal; Erythrocytes; Erythropoietin; Humans; Infant, Newborn