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Kundu MC, Gore LR, Maguire S, Gilmartin AG. Development and Characterization of a Model for Inducing Fetal Hemoglobin Production in Cynomolgus Macaques ( Macaca fasicularis). Comp Med 2018; 68:396-402. [PMID: 30092854 DOI: 10.30802/aalas-cm-17-000124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hydroxyurea induces production of fetal hemoglobin (HbF), a tetramer of α and γ globin proteins and corresponding heme molecules, normally found in less than 1% of adult RBC. Increases in circulating HbF are correlated with clinical improvement of patients with hemoglobinopathies, and hydroxyurea, as a daily medication, is the standard treatment for sickle cell anemia. Although olive baboons (Papio anubis) are considered a key model species for HbF induction, cynomolgus macaques (Macaca fasicularis) are another species that conserves the ability to produce HbF into maturity. In this study, moderate anemia was experimentally induced in cynomolgus macaques by phlebotomy, to stimulate accelerated erythropoiesis and HbF production. In contrast to previous studies, vascular access ports were implanted for phlebotomy of conscious monkeys, followed by fluid replacement. As total Hgb levels dropped, reticulocyte counts and the percentage of HbF-expressing cells increased. Once total Hgb levels declined to less than 8 g/dL, 2 courses of oral hydroxyurea (once daily for 5 d) were completed, with a 9-d interval between courses. After hydroxyurea dosing, the percentage of HbF-expressing cells and total HbF were increased significantly. In addition, a significant but transient decrease in reticulocyte count and a transient increase in MCV occurred, replicating the characteristic response of patients receiving hydroxyurea. Daily clinical observations revealed no serious health issues or decreases in food consumption or activity levels. Methods were established for assessing the patency of vascular access ports. This study details a new protocol for the safe and routine induction of moderate anemia in cynomolgus macaques and validates its use in the investigation of novel pharmacologic entities to induce the production of HbF.
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Affiliation(s)
- Mila C Kundu
- Integrated Biological Platform Sciences, GlaxoSmithKline Research and Development, Collegeville, Pennsylvania, USA; Veterinary Sciences, Bristol-Myers Squibb, New Brunswick, New Jersey, USA
| | - Liz R Gore
- Haemoglobin DPU, GlaxoSmithKline Research and Development, Collegeville, Pennsylvania, USA
| | - Sean Maguire
- Integrated Biological Platform Sciences, GlaxoSmithKline Research and Development, Collegeville, Pennsylvania, USA.
| | - Aidan G Gilmartin
- Haemoglobin DPU, GlaxoSmithKline Research and Development, Collegeville, Pennsylvania, USA
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2
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Youssry I, Abdel-Salam A, Ismail R, Bou-Fakhredin R, Mohamed Samy R, Ezz El-Deen F, Taher AT. Enhancing Effect of Hydroxyurea on Hb F in Sickle Cell Disease: Ten-Year Egyptian Experience. Hemoglobin 2017; 41:267-273. [DOI: 10.1080/03630269.2017.1408646] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ilham Youssry
- Pediatric Hematology and Bone Marrow Transplantation Unit, Pediatric Department, Faculty of Medicine, Cairo University, Egypt
| | - Amina Abdel-Salam
- Pediatric Hematology and Bone Marrow Transplantation Unit, Pediatric Department, Faculty of Medicine, Cairo University, Egypt
| | - Rania Ismail
- Pediatric Hematology and Bone Marrow Transplantation Unit, Pediatric Department, Faculty of Medicine, Cairo University, Egypt
| | - Rayan Bou-Fakhredin
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rania Mohamed Samy
- Clinical Pathology Department, Faculty of Medicine, Cairo University, Egypt
| | - Fatma Ezz El-Deen
- Pediatric Hematology and Bone Marrow Transplantation Unit, Pediatric Department, Faculty of Medicine, Cairo University, Egypt
| | - Ali T. Taher
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
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3
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Daak AA, Elsamani E, Ali EH, Mohamed FA, Abdel-Rahman ME, Elderdery AY, Talbot O, Kraft P, Ghebremeskel K, Elbashir MI, Fawzi W. Sickle cell disease in western Sudan: genetic epidemiology and predictors of knowledge attitude and practices. Trop Med Int Health 2016; 21:642-53. [PMID: 27028397 PMCID: PMC10699227 DOI: 10.1111/tmi.12689] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate the epidemiology of sickle cell disease (SCD) and determinants of knowledge, attitudes and practices (KAP) towards SCD in western Kordofan State, Sudan. METHODS A community-based, descriptive, cross-sectional study was conducted in three towns. Three hundred and seventy-two households were polled, and blood samples for haemoglobin phenotyping were collected from 1116 individuals. Sociodemographic, socio-economic and KAP data were collected using investigator-administered questionnaires. Descriptive, frequency distribution and multiple regression analyses were performed. RESULTS About 50.9% of the study population were Misseriya tribes. Consanguineous marriages were reported by 67.5% of the households. The highest percentage of homozygous SCD was 2.8% among children under 5 years of age. About 24.9% were carriers of HbS allele (HbAS). HbS allele frequency was highest in children aged 5-11 years (18.3%, CI: 13.7-22.9%) and lowest in males >15 years old (12.0%, CI: 6.1-17.9%). The average HbS frequency across all age groups was 14.5% (95% CI: 12.2-16.8%). The most frequent β-globin gene cluster haplotype was the Cameroon (30.8%), followed by the Benin (21.8%), the Senegal (12.8%) and the Bantu (2.2%) haplotypes. About 17.0% of all-cause child deaths were due to SCD. The estimated change in log odds of having the SS genotype per year increase in age was (-) 0.0058 (95% CI -0.0359, 0.0242). This represents a non-statistically significant 2.9% increase in 5-year mortality for individuals with the SS genotype relative to those with AS and AA genotypes. About 46.9% of the households had poor knowledge, 26.1% had satisfactory knowledge, and 26.9% had good knowledge about sickle cell disease. Mothers' and fathers' educational levels were significant predictors of good knowledge about SCD (P < 0.05). About 48.0% had a satisfactory attitude towards sickle cell disease while 30.7% had poor attitude and only 21.3 showed good attitudes. Poor knowledge about SCD and low socio-economic status were the strongest positive predictors of poor attitude and practices towards SCD (P < 0.01). CONCLUSIONS Sickle cell disease is a major health problem in West Kordofan, Sudan. Knowledge, attitude and practices towards the disease are not satisfactory. The development of public health programs is highly recommended to control and manage SCD in western parts of Sudan.
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Affiliation(s)
- Ahmed A. Daak
- Department of Global Health and Population, Harvard University, Boston, MA, USA
- Department of Medical Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Elfatih Elsamani
- Department of Community Medicine, School of Medicine, Ahfad University for Women, Khartoum, Sudan
| | - Eltigani H. Ali
- Lipidomics and Nutrition Research Centre, Faculty of Life Sciences and Computing, London Metropolitan University, London, UK
| | - Fatma A Mohamed
- School of Nursing Sciences, University of Khartoum, Khartoum, Sudan
| | - Manar E. Abdel-Rahman
- Department of Statistics, Faculty of Mathematical Sciences, University of Khartoum, Khartoum, Sudan
| | - Abozer Y. Elderdery
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Octavious Talbot
- Department of Biostatistics, Harvard University, Boston, MA, USA
| | - Peter Kraft
- Department of Biostatistics, Harvard University, Boston, MA, USA
| | - Kebreab Ghebremeskel
- Lipidomics and Nutrition Research Centre, Faculty of Life Sciences and Computing, London Metropolitan University, London, UK
| | - Mustafa I. Elbashir
- Department of Medical Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Wafaie Fawzi
- Department of Global Health and Population, Harvard University, Boston, MA, USA
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4
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Agrawal RK, Patel RK, Shah V, Nainiwal L, Trivedi B. Hydroxyurea in sickle cell disease: drug review. Indian J Hematol Blood Transfus 2013; 30:91-6. [PMID: 24839362 DOI: 10.1007/s12288-013-0261-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/15/2013] [Indexed: 11/27/2022] Open
Abstract
Hydroxyurea, a myelosuppressive agent, is the only effective drug proven to reduce the frequency of painful episodes. It raises the level of HbF and the haemoglobin level. It usually decreases the rate of painful episodes by 50 %. It was first tested in sickle cell disease in 1984. It also decreases the rate of ACS episodes and blood transfusions by ~50 % in adults. It was developed as an anticancer drug and has been used to treat myeloproliferative syndromes-leukemia, melanoma, and ovarian cancer. It was approved for use by FDA in adults. Side effects includes neutropenia, bone marrow suppression, elevation of hepatic enzymes, anorexia, nausea, vomiting and infertility.
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Affiliation(s)
- Rohit Kumar Agrawal
- Dhiraj General Hospital, D-7, Staff Quarters, Pipariya, Vadodara, Gujarat India
| | | | - Varsha Shah
- Dhiraj General Hospital, D-7, Staff Quarters, Pipariya, Vadodara, Gujarat India
| | - Lalit Nainiwal
- Dhiraj General Hospital, D-7, Staff Quarters, Pipariya, Vadodara, Gujarat India
| | - Bhadra Trivedi
- Dhiraj General Hospital, D-7, Staff Quarters, Pipariya, Vadodara, Gujarat India
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Gee BE. Biologic complexity in sickle cell disease: implications for developing targeted therapeutics. ScientificWorldJournal 2013; 2013:694146. [PMID: 23589705 PMCID: PMC3621302 DOI: 10.1155/2013/694146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 01/29/2013] [Indexed: 01/01/2023] Open
Abstract
Current therapy for sickle cell disease (SCD) is limited to supportive treatment of complications, red blood cell transfusions, hydroxyurea, and stem cell transplantation. Difficulty in the translation of mechanistically based therapies may be the result of a reductionist approach focused on individual pathways, without having demonstrated their relative contribution to SCD complications. Many pathophysiologic processes in SCD are likely to interact simultaneously to contribute to acute vaso-occlusion or chronic vasculopathy. Applying concepts of systems biology and network medicine, models were developed to show relationships between the primary defect of sickle hemoglobin (Hb S) polymerization and the outcomes of acute pain and chronic vasculopathy. Pathophysiologic processes such as inflammation and oxidative stress are downstream by-products of Hb S polymerization, transduced through secondary pathways of hemolysis and vaso-occlusion. Pain, a common clinical trials endpoint, is also complex and may be influenced by factors outside of sickle cell polymerization and vascular occlusion. Future sickle cell research needs to better address the biologic complexity of both sickle cell disease and pain. The relevance of individual pathways to important sickle cell outcomes needs to be demonstrated in vivo before investing in expensive and labor-intensive clinical trials.
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Affiliation(s)
- Beatrice E Gee
- Department of Pediatrics, Cardiovascular Research Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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The potential role of cell penetrating peptides in the intracellular delivery of proteins for therapy of erythroid related disorders. Pharmaceuticals (Basel) 2013; 6:32-53. [PMID: 24275786 PMCID: PMC3816679 DOI: 10.3390/ph6010032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/20/2012] [Accepted: 12/27/2012] [Indexed: 01/08/2023] Open
Abstract
The erythroid related disorders (ERDs) represent a large group of hematological diseases, which in most cases are attributed either to the deficiency or malfunction of biosynthetic enzymes or oxygen transport proteins. Current treatments for these disorders include histo-compatible erythrocyte transfusions or allogeneic hematopoietic stem cell (HSC) transplantation. Gene therapy delivered via suitable viral vectors or genetically modified HSCs have been under way. Protein Transduction Domain (PTD) technology has allowed the production and intracellular delivery of recombinant therapeutic proteins, bearing Cell Penetrating Peptides (CPPs), into a variety of mammalian cells. Remarkable progress in the field of protein transduction leads to the development of novel protein therapeutics (CPP-mediated PTs) for the treatment of monogenetic and/or metabolic disorders. The “concept” developed in this paper is the intracellular protein delivery made possible via the PTD technology as a novel therapeutic intervention for treatment of ERDs. This can be achieved via four stages including: (i) the production of genetically engineered human CPP-mediated PT of interest, since the corresponding native protein either is missing or is mutated in the erythroid progenitor cell (ErPCs) or mature erythrocytes of patients; (ii) isolation of target cells from the peripheral blood of the selected patients; (iii) ex vivo transduction of cells with the CPP-mediated PT of interest; and (iv) re-administration of the successfully transduced cells back into the same patients.
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Huston SA, Houk CP. Common sense model of illness in youth with type 1 diabetes or sickle cell disease. J Pediatr Pharmacol Ther 2012; 16:270-80. [PMID: 22768011 DOI: 10.5863/1551-6776-16.4.270] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES To qualitatively explore differences in Leventhal's common sense model (CSM) constructs between youth with type 1 diabetes (T1D) and sickle cell disease (SCD) and between different age groups and level of disease control. METHODS Two structured individual interviews were conducted in 24 youth with T1D (n=12) or SCD (n=12). Patients were between 8 and 21 years of age, had either good or poor disease control, and were seen at an outpatient children's hospital medical clinic. RESULTS YOUTH CONCEPTUALIZE THEIR CHRONIC DISEASE IN TERMS OF IDENTITY, CAUSE, TIMELINE, CONTROL, AND CONSEQUENCES: both cognitive and emotional dimensions are apparent. There was considerable contrast between discussions of youth with well- and poorly controlled T1D but little contrast between youth with well- and poorly controlled SCD. Surprisingly, youth with well-controlled T1D mentioned emotions most frequently. No youth with poorly controlled T1D described disease acceptance, but the majority of youth with well-controlled T1D did. Adolescents and young adults with good T1D control appear to understand disease cause, have better illness coherence, and habitually link discussion of symptoms and negative emotions with solutions. Youth with poorly controlled T1D appeared more likely to connect symptoms with negative consequences. Consequences included 1) disease symptoms, 2) the need to perform self-care activities, 3) physical outcomes, 4) health-system activities, 5) emotions, and 6) life impact. Interestingly, sickling crisis was mentioned more frequently by youth with good SCD control than by those with poor SCD control. Youth with SCD are distressed by others' judgmental perceptions and by feeling different from others. CONCLUSIONS In contrast to previous CSM work, youth with well-controlled T1D in this study discussed emotions more frequently than did those with poor control. Disease perceptions were similar between youth with well- and poorly controlled SCD. Results indicate there are noteworthy cognitive and emotional differences between youth with different types of disease and levels of disease control.
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Dos Santos JL, Lanaro C, Chelucci RC, Gambero S, Bosquesi PL, Reis JS, Lima LM, Cerecetto H, González M, Costa FF, Chung MC. Design, synthesis, and pharmacological evaluation of novel hybrid compounds to treat sickle cell disease symptoms. part II: furoxan derivatives. J Med Chem 2012; 55:7583-92. [PMID: 22889416 DOI: 10.1021/jm300602n] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phthalimide derivatives containing furoxanyl subunits as nitric oxide (NO)-donors (3a-g) were designed, synthesized, and evaluated in vitro and in vivo for their potential uses in the oral treatment of sickle cell disease symptoms. All compounds (3a-g) demonstrated NO-donor properties at different levels. Moreover, compounds 3b and 3c demonstrated analgesic activity. Compound 3b was determined to be a promising drug candidate for the aforementioned uses, and it was further evaluated in K562 culture cells to determine its ability to increase levels of γ-globin expression. After 96 h at 5 μM, compound 3b was able to induce γ-globin expression by nearly three times. Mutagenic studies using micronucleus tests in peripheral blood cells of mice demonstrated that compound 3b reduces the mutagenic profile as compared with hydroxyurea. Compound 3b has emerged as a new leading drug candidate with multiple beneficial effects for the treatment of sickle cell disease symptoms and provides an alternative to hydroxyurea treatment.
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Affiliation(s)
- Jean Leandro Dos Santos
- Lapdesf-Laboratório de Pesquisa e Desenvolvimento de Fármacos, Departamento de Fármacos e Medicamentos, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista-UNESP, Rodovia Araraquara Jaú Km. 01, 14801-902 Araraquara, SP, Brazil.
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9
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Abstract
Abstract
Emerging metabolomic tools can now be used to establish metabolic signatures of specialized circulating hematopoietic cells in physiologic or pathologic conditions and in human hematologic diseases. To determine metabolomes of normal and sickle cell erythrocytes, we used an extraction method of erythrocytes metabolites coupled with a liquid chromatography-mass spectrometry–based metabolite profiling method. Comparison of these 2 metabolomes identified major changes in metabolites produced by (1) endogenous glycolysis characterized by accumulation of many glycolytic intermediates; (2) endogenous glutathione and ascorbate metabolisms characterized by accumulation of ascorbate metabolism intermediates, such as diketogulonic acid and decreased levels of both glutathione and glutathione disulfide; (3) membrane turnover, such as carnitine, or membrane transport characteristics, such as amino acids; and (4) exogenous arginine and NO metabolisms, such as spermine, spermidine, or citrulline. Finally, metabolomic analysis of young and old normal red blood cells indicates metabolites whose levels are directly related to sickle cell disease. These results show the relevance of metabolic profiling for the follow-up of sickle cell patients or other red blood cell diseases and pinpoint the importance of metabolomics to further depict the pathophysiology of human hematologic diseases.
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Perampaladas K, Masum H, Kapoor A, Shah R, Daar AS, Singer PA. The road to commercialization in Africa: lessons from developing the sickle-cell drug Niprisan. BMC INTERNATIONAL HEALTH AND HUMAN RIGHTS 2010; 10 Suppl 1:S11. [PMID: 21144071 PMCID: PMC3001608 DOI: 10.1186/1472-698x-10-s1-s11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background Developing novel drugs from traditional medicinal knowledge can serve as a means to improve public health. Yet countries in sub-Saharan Africa face barriers in translating traditional medicinal knowledge into commercially viable health products. Barriers in moving along the road towards making a new drug available include insufficient manufacturing capacity; knowledge sharing between scientists and medical healers; regulatory hurdles; quality control issues; pricing and distribution; and lack of financing. The case study method was used to illustrate efforts to overcome these barriers during the development in Nigeria of Niprisan – a novel drug for the treatment of sickle cell anemia, a chronic blood disorder with few effective therapies. Discussion Building on the knowledge of a traditional medicine practitioner, Nigeria’s National Institute for Pharmaceutical Research and Development (NIPRD) developed the traditional herbal medicine Niprisan. The commercialization of Niprisan reached a number of commercial milestones, including regulatory approval in Nigeria; securing US-based commercial partner XeChem; demonstrating clinical efficacy and safety; being awarded orphan drug status by the US Food and Drug Administration; and striking important relationships with domestic and international groups. Despite these successes, however, XeChem did not achieve mainstream success for Niprisan in Nigeria or in the United States. A number of reasons, including inconsistent funding and manufacturing and management challenges, have been put forth to explain Niprisan’s commercial demise. As of this writing, NIPRD is considering options for another commercial partner to take the drug forward. Summary Evidence from the Niprisan experience suggests that establishing benefit-sharing agreements, fostering partnerships with established research institutions, improving standardization and quality control, ensuring financial and managerial due diligence, and recruiting entrepreneurial leaders capable of holding dual scientific and business responsibilities should be incorporated into future drug development initiatives based on traditional medicines. Country-level supporting policies and conditions are also important. With more experience and support, and an improved environment for innovation, developing new drugs from traditional medicines may be an attractive approach to addressing diseases in sub-Saharan Africa and other regions.
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Affiliation(s)
- Kumar Perampaladas
- McLaughlin-Rotman Centre for Global Health, University Health Network and University of Toronto, 101 College Street Suite 406, Toronto ON, M5G 1L7, Canada
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11
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Elagouz M, Jyothi S, Gupta B, Sivaprasad S. Sickle Cell Disease and the Eye: Old and New Concepts. Surv Ophthalmol 2010; 55:359-77. [DOI: 10.1016/j.survophthal.2009.11.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 11/15/2009] [Accepted: 11/17/2009] [Indexed: 10/19/2022]
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Ware RE. How I use hydroxyurea to treat young patients with sickle cell anemia. Blood 2010; 115:5300-11. [PMID: 20223921 PMCID: PMC2902131 DOI: 10.1182/blood-2009-04-146852] [Citation(s) in RCA: 261] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 02/16/2010] [Indexed: 01/26/2023] Open
Abstract
Hydroxyurea has many characteristics of an ideal drug for sickle cell anemia (SCA) and provides therapeutic benefit through multiple mechanisms of action. Over the past 25 years, substantial experience has accumulated regarding its safety and efficacy for patients with SCA. Early proof-of-principle studies were followed by prospective phase 1/2 trials demonstrating efficacy in affected adults, then adolescents and children, and more recently infants and toddlers. The phase 3 National Heart, Lung and Blood Institute-sponsored Multicenter Study of Hydroxyurea trial proved clinical efficacy for preventing acute vaso-occlusive events in severely affected adults. Based on this cumulative experience, hydroxyurea has emerged as an important therapeutic option for children and adolescents with recurrent vaso-occlusive events; recent evidence documents sustained long-term benefits with prevention or reversal of chronic organ damage. Despite abundant evidence for its efficacy, however, hydroxyurea has not yet translated into effective therapy for SCA. Because many healthcare providers have inadequate knowledge about hydroxyurea, patients and families are not offered treatment or decline because of unrealistic fears. Limited support for hydroxyurea by lay organizations and inconsistent medical delivery systems also contribute to underuse. Although questions remain regarding its long-term risks and benefits, current evidence suggests that many young patients with SCA should receive hydroxyurea treatment.
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Affiliation(s)
- Russell E Ware
- Department of Hematology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
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13
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Juul T, Malolepszy A, Dybkaer K, Kidmose R, Rasmussen JT, Andersen GR, Johnsen HE, Jørgensen JE, Andersen SU. The in vivo toxicity of hydroxyurea depends on its direct target catalase. J Biol Chem 2010; 285:21411-5. [PMID: 20452979 PMCID: PMC2898382 DOI: 10.1074/jbc.m110.103564] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hydroxyurea (HU) is a well tolerated ribonucleotide reductase inhibitor effective in HIV, sickle cell disease, and blood cancer therapy. Despite a positive initial response, however, most treated cancers eventually progress due to development of HU resistance. Although RNR properties influence HU resistance in cell lines, the mechanisms underlying cancer HU resistance in vivo remain unclear. To address this issue, we screened for HU resistance in the plant Arabidopsis thaliana and identified seventeen unique catalase mutants, thereby establishing that HU toxicity depends on catalase in vivo. We further demonstrated that catalase is a direct HU target by showing that HU acts as a competitive inhibitor of catalase-mediated hydrogen peroxide decomposition. Considering also that catalase can accelerate HU decomposition in vitro and that co-treatment with another catalase inhibitor alleviates HU effects in vivo, our findings suggests that HU could act as a catalase-activated pro-drug. Clinically, we found high catalase activity in circulating cells from untreated chronic myeloid leukemia, offering a possible explanation for the efficacy of HU against this malignancy.
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Affiliation(s)
- Trine Juul
- Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10, DK-8000 Aarhus, Denmark
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14
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Abstract
Sickle cell anemia is one of the most common autosomal recessive diseases in the world. Patients with sickle cell anemia have variable penetrance and it is hard to predict the risk and timing of complications. It is characterized by a point mutation in the beta-globin gene (GAG --> GTG) and the production of hemoglobin S. The latter leads to decreased deformability of the red blood cells (RBCs) that adhere to endothelia cells culminating in vascular occlusion and its sequelae of tissue ischemia and organ damage. Moreover, sickled RBCs undergo intravascular hemolysis and accelerated erythropoesis. The hallmarks of this disease are shortened RBC survival and vaso-occlusive crises. For the past ten years, the pathophysiology of this disease has been better elucidated and has led to significant improvements in the standard of care. Vaso-occlusion is now understood to be a complex event that involves abnormal interactions between RBCs, leukocytes, endothelial cells and the coagulation pathways. The field of translational research in sickle cell anemia has expanded greatly and has led to new clinical trials with new therapeutic agents and strategies. In this paper, we review the drugs that are now being investigated in the treatment of sickle cell anemia.
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Smith WR, Scherer M. Sickle-cell pain: advances in epidemiology and etiology. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2010; 2010:409-415. [PMID: 21239827 DOI: 10.1182/asheducation-2010.1.409] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
New epidemiological findings recast pain in sickle-cell disease (SCD) as being more often a chronic manifestation than was previously thought, although acute pain is still the hallmark of the disease. SCD pain intensity, the number of painful locations, and the frequency of hospitalizations due to SCD pain may worsen with age. In adults and even in children, the quantity and severity of SCD pain may be vastly underestimated, because most of the "iceberg" of SCD pain is "submerged" at home, and only the tip of the iceberg is seen by health care providers when acute SCD care is rendered in emergency rooms and hospitals. Implications of this "iceberg phenomenon" are significant for clinicians, researchers, employers, policy makers, and the public. Nevertheless, both emergency room and hospital utilization for SCD pain remain prevalent. Often, utilization recurs early, perhaps emblematic of poor acute pain management. New data show the protean impacts of SCD pain on health-related quality of life, sleep, and psychological and social health. The relationship of the severity of SCD pain to the severity of underlying sickle vasculopathy is unclear, but epidemiologic evidence and patient descriptors suggest a temporal evolution of pain mechanisms. At first, increasingly worse nociceptive pain from vaso-occlusion and local lesions may evolve over the first two decades of life. Then, in the third and following decades, central neuropathic pain may also evolve due to past and continuing nociceptive stimuli. New findings confirm environmental contributors to SCD pain, including seasonal (colder) temperatures, barometric pressure, and wind speed.
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Affiliation(s)
- Wally R Smith
- Division of Quality Health Care, Virginia Commonwealth University, Richmond, VA 23298-0306, USA.
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16
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Conran N, Costa FF. Hemoglobin disorders and endothelial cell interactions. Clin Biochem 2009; 42:1824-38. [PMID: 19580799 DOI: 10.1016/j.clinbiochem.2009.06.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/20/2009] [Indexed: 11/15/2022]
Abstract
Endothelial damage and inflammation make a significant contribution to the pathophysiology of sickle cell disease (SCD) and the beta-thalassemia syndromes. Endothelial dysfunction and ensuing vasculopathy are implicated in pulmonary hypertension in the hemoglobinopathies and endothelial activation and endothelial-blood cell adhesion, accompanied by inflammatory processes and oxidative stress, are imperative to the vaso-occlusive process in SCD. Herein, we discuss the role that the endothelium plays in all of these processes and the effect that genetic modifiers and hydroxyurea therapy may have upon endothelial interactions. Therapies targeting the endothelium and endothelial interactions may represent a promising approach for treating these diseases.
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Affiliation(s)
- Nicola Conran
- Hematology and Hemotherapy Centre, School of Medical Sciences, University of Campinas - UNICAMP, Brazil.
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Abstract
Despite an increased understanding of the pathophysiology of sickle cell disease (SCD), there remains a paucity of available agents for the prevention and treatment of specific SCD-related complications. Recently, there has been significant progress in the development of novel drugs for this disease. These agents, which increase the production of fetal hemoglobin, improve red blood cell hydration, increase the availability of nitric oxide and possess anti-inflammatory effects, are in varying stages of clinical development. With the complex pathophysiology of SCD, it is unlikely that a single agent will prevent or treat all the sequelae of this disease. As a result, patients may benefit from treatment with a combination of agents that possess different mechanisms of action. This overview discusses selected novel agents that appear promising in SCD.
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18
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Abstract
AbstractDespite an increased understanding of the pathophysiology of sickle cell disease (SCD), there remains a paucity of available agents for the prevention and treatment of specific SCD-related complications. Recently, there has been significant progress in the development of novel drugs for this disease. These agents, which increase the production of fetal hemoglobin, improve red blood cell hydration, increase the availability of nitric oxide and possess anti-inflammatory effects, are in varying stages of clinical development. With the complex pathophysiology of SCD, it is unlikely that a single agent will prevent or treat all the sequelae of this disease. As a result, patients may benefit from treatment with a combination of agents that possess different mechanisms of action. This overview discusses selected novel agents that appear promising in SCD.
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