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Okpala I, Nonyelu C, Muoghalu E, Anigbogu I, Onodugo C, Ilechukwu U, Fidelis-Ewa U, Duru A, Okoye H. Preclinical therapeutics for sickle cell disease: modern developments and future considerations. Expert Opin Investig Drugs 2025; 34:301-315. [PMID: 40323290 DOI: 10.1080/13543784.2025.2500289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 04/02/2025] [Indexed: 05/14/2025]
Abstract
INTRODUCTION Most of the current treatment modalities for sickle hemoglobinopathy are disease-modifying rather than curative. Therefore, there is a need for effective treatment of complications of sickle cell disease (SCD) that impair quality of life. This need drives the evaluation of preclinical therapeutics in search of new treatment modalities. AREAS COVERED Interventions are likely to progress from research to clinical practice, their potential impact, and future directions in SCD care: HbF inducers, pyruvate kinase activators, anti-selectin P monoclonal antibodies, allosteric Hb modifiers, proactive treatment of cerebral artery conditional blood velocity, multimodal, and gene therapy. Established treatment modalities (e.g with hydroxyurea) are not included because these have advanced well beyond the preclinical stage of therapeutics. Information dated 2025 backward was obtained from Medline, PubMed, and other public sources. EXPERT OPINION Places for the conduct of preclinical studies ought to include areas of high SCD prevalence. Limited resources currently hinder universal accessibility of curative SCD therapies in these places. The recent approval of non-viral gene therapy for SCD and the number of preclinical therapeutics in development bring realistic expectation that curative and disease-modifying interventions, such as multimodal therapy and proactive treatment of cerebral artery conditional blood velocity to prevent stroke, will become standard care.
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Affiliation(s)
- Iheanyi Okpala
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Charles Nonyelu
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Ebele Muoghalu
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Ikechukwu Anigbogu
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Chinenye Onodugo
- Department of Pharmacy, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Udoka Ilechukwu
- Department of Pharmacy, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Uwaoma Fidelis-Ewa
- Department of Pharmacy, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Augustine Duru
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
| | - Helen Okoye
- Department of Hematology, University of Nigeria Teaching Hospital, Enugu, Nigeria
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Bernardo VS, Torres FF, Zucão ACA, Chaves NA, Santana ILR, da Silva DGH. Disrupted homeostasis in sickle cells: Expanding the comprehension of metabolism adaptation and related therapeutic strategies. Tissue Cell 2025; 93:102717. [PMID: 39805212 DOI: 10.1016/j.tice.2024.102717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2024] [Revised: 12/02/2024] [Accepted: 12/29/2024] [Indexed: 01/16/2025]
Abstract
Sickle cell disease (SCD) is a hereditary hemolytic anemia associated with the alteration of the membrane composition of the sickle erythrocytes, the loss of glycolysis, dysregulation of the pyruvate phosphatase pathway, and changes in nucleotide metabolism of the sickle red blood cell (RBC). This review provides a comprehensive overview of the impact of the presence of Hb S, which leads to the disruption of the normal RBC metabolism. The intricate interplay between the redox and energetic balance in erythrocytic cells, where the glycolysis, pentose phosphate pathway, and methemoglobin reductase pathways are all altered in sickle RBC, is a key focus. Moreover, this review summarizes the current knowledge about the disease-modifying agents and their action mechanisms based on the sickle RBC alterations previously mentioned (i.e., their association with beneficial effects on the sickle cells' membrane, to their RBCs' energy metabolism, and to their oxidative status). Therefore, providing a comprehensive understanding of how sickle cells cope with the disruption of metabolic homeostasis and the most promising therapeutic agents able to ameliorate the various consequences of abnormal sickle RBC alterations.
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Affiliation(s)
| | | | | | - Nayara Alves Chaves
- Department of Biology, Universidade Estadual Paulista (UNESP), São Paulo, Brazil
| | | | - Danilo Grünig Humberto da Silva
- Department of Biology, Universidade Estadual Paulista (UNESP), São Paulo, Brazil; Campus de Três Lagoas, Universidade Federal de Mato Grosso do Sul (CPTL/UFMS), Mato Grosso do Sul, Brazil.
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Pressiat C, Rakotoson MG, Habibi A, Barau C, Arrouasse R, Galactéros F, Stehlé T, Audard V, Hulin A, Bartolucci P. Impact of renal function on hydroxyurea exposure in sickle-cell disease patients. Br J Clin Pharmacol 2020; 87:2274-2285. [PMID: 33217005 DOI: 10.1111/bcp.14653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/24/2020] [Accepted: 10/13/2020] [Indexed: 12/17/2022] Open
Abstract
AIMS This prospective study aimed to develop a population pharmacokinetics (PK) model of hydroxyurea (HU) in patients with sickle cell disease. This model can be used to determine the impact of glomerular filtration rate (GFR) on HU kinetics. METHODS We included 30 patients. They underwent HU pharmacokinetics analyses of plasma and urine. Six underwent PK analyses in 2 periods with and without angiotensin-converting enzyme inhibitor. HU was assayed with a validated high-performance liquid chromatography-UV method. Noncompartmental PK analysis was conducted and a population PK model built with Monolix. This model was validated externally on another 56 patients. HU PK was simulated as a function of GFR. RESULTS The HU PK model was constructed as a 2-compartment model with first-order absorption and elimination. The quality criteria were good, including for external validation. We found that estimated GFR (eGFR) and body weight affected HU PK, with lower eGFR or body weight associated with a higher HU area under the curve. We recommend the monitoring of HU through eGFR and body weight, which together account for 47% of its variability. Urinary HU fractions and renal clearance were higher in the glomerular hyperfiltration group and lower in the moderate chronic kidney disease group, respectively. No differences in nonrenal HU clearance were observed. CONCLUSION Estimated GFR has an impact on the kinetics of hydroxyurea, and HU dose should be adapted accordingly. Angiotensin-converting enzyme inhibitor seems to have minor effect on HU PK in adults with sickle cell disease.
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Affiliation(s)
- Claire Pressiat
- Laboratoire de Pharmacologie, Assistance Publique des Hôpitaux de Paris (AP-HP), Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Marie-Georgine Rakotoson
- Centre de référence pour les syndromes drépanocytaires majeurs, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France.,Filière MCGRE. DHU A TVB. Institut Mondor de Recherche Biomédicale (IMRB) équipe 2. Laboratoire d'excellence GRex, Université Paris Est-Créteil, Créteil, France
| | - Anoosha Habibi
- Centre de référence pour les syndromes drépanocytaires majeurs, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Caroline Barau
- Plate-forme de Ressources Biologiques, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Raphaele Arrouasse
- Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Investigations Cliniques 1430, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Frédéric Galactéros
- Centre de référence pour les syndromes drépanocytaires majeurs, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Thomas Stehlé
- Service de Néphrologie et Transplantation, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil, France.,Inserm U955, équipe 21, IMRB, Université Paris Est-Créteil, Créteil, France
| | - Vincent Audard
- Service de Néphrologie et Transplantation, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil, France.,Inserm U955, équipe 21, IMRB, Université Paris Est-Créteil, Créteil, France
| | - Anne Hulin
- Laboratoire de Pharmacologie, Assistance Publique des Hôpitaux de Paris (AP-HP), Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France
| | - Pablo Bartolucci
- Centre de référence pour les syndromes drépanocytaires majeurs, AP-HP, Hôpitaux Universitaires Henri Mondor, Université Paris Est-Créteil, Créteil, France.,Filière MCGRE. DHU A TVB. Institut Mondor de Recherche Biomédicale (IMRB) équipe 2. Laboratoire d'excellence GRex, Université Paris Est-Créteil, Créteil, France
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Biochemical and therapeutic effects of Omega-3 fatty acids in sickle cell disease. Complement Ther Med 2020; 52:102482. [PMID: 32951732 DOI: 10.1016/j.ctim.2020.102482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 01/29/2023] Open
Abstract
Sickle cell disease (SCD) is a hematologic disorder with complex pathophysiology that includes chronic hemolysis, vaso-occlusion and inflammation. Increased leukocyte-erythrocyte-endothelial interactions, due to upregulated expression of adhesion molecules and activated endothelium, are thought to play a primary role in initiation and progression of SCD vaso-occlusive crisis and end-organ damage. Several new pathophysiology-based therapeutic options for SCD are being developed, chiefly targeting the inflammatory pathways. Omega-3 fatty acids are polyunsaturated fatty acids that are known to have effects on diverse physiological processes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the principal biologically active omega-3 fatty acids. The therapeutic effects of DHA and EPA on chronic inflammatory disorders and cardiovascular diseases are well recognized. The therapeutic effects of omega-3 fatty acids are attributed to their anti-inflammatory and anti-thrombotic eicosanoids, and the novel class of EPA and DHA derived lipid mediators: resolvins, protectins and maresins. Blood cell membranes of patients with SCD have abnormal fatty acids composition characterized by high ratio of pro-inflammatory arachidonic acid (AA) to anti-inflammatory DHA and EPA (high omega-6/omega-3 ratio). In addition, experimental and clinical studies provide evidence that treatment with DHA does confer improvement in rheological properties of sickle RBC, inflammation and hemolysis. The clinical studies have shown improvements in VOC rate, markers of inflammation, adhesion, and hemolysis. In toto, the results of studies on the therapeutic effects of omega-3 fatty acids in SCD provide good body of evidence that omega-3 fatty acids could be a safe and effective treatment for SCD.
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Adewoyin AS. Management of sickle cell disease: a review for physician education in Nigeria (sub-saharan Africa). Anemia 2015; 2015:791498. [PMID: 25667774 PMCID: PMC4312619 DOI: 10.1155/2015/791498] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/18/2014] [Accepted: 12/17/2014] [Indexed: 11/27/2022] Open
Abstract
Sickle cell disease (SCD) predominates in sub-Saharan Africa, East Mediterranean areas, Middle East, and India. Nigeria, being the most populous black nation in the world, bears its greatest burden in sub-Saharan Africa. The last few decades have witnessed remarkable scientific progress in the understanding of the complex pathophysiology of the disease. Improved clinical insights have heralded development and establishment of disease modifying interventions such as chronic blood transfusions, hydroxyurea therapy, and haemopoietic stem cell transplantation. Coupled with parallel improvements in general supportive, symptomatic, and preventive measures, current evidence reveals remarkable appreciation in quality of life among affected individuals in developed nations. Currently, in Nigeria and other West African states, treatment and control of SCD are largely suboptimal. Improved knowledge regarding SCD phenotypes and its comprehensive care among Nigerian physicians will enhance quality of care for affected persons. This paper therefore provides a review on the aetiopathogenesis, clinical manifestations, and management of SCD in Nigeria, with a focus on its local patterns and peculiarities. Established treatment guidelines as appropriate in the Nigerian setting are proffered, as well as recommendations for improving care of affected persons.
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Affiliation(s)
- Ademola Samson Adewoyin
- Department of Haematology and Blood Transfusion, University of Benin Teaching Hospital, PMB 1111, Benin City, Edo State, Nigeria
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Shahine R, Badr LK, Karam D, Abboud M. Educational intervention to improve the health outcomes of children with sickle cell disease. J Pediatr Health Care 2015; 29:54-60. [PMID: 25115311 DOI: 10.1016/j.pedhc.2014.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 06/10/2014] [Accepted: 06/21/2014] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Although sickle cell disease (SCD) is the most common single gene disorder worldwide, caregivers of children do not have adequate knowledge about the illness and its management. The purpose of this study was to assess the efficacy of education along with tailored written materials in changing the behaviors of caregivers to help them provide better care for children with SCD. METHODS A preintervention and postintervention quasi-experimental design was used. A convenience sample of 43 caregivers of 57 children were asked to complete a questionnaire related to their knowledge of SCD before and after educational sessions. The educational sessions (the intervention) were provided to caregivers at the Children's Cancer Center in Lebanon by one registered nurse, one certified pediatric nurse practitioner, and one pediatric hematologist. Emergency department (ED) visits and hospitalizations were compared 2 months before and 2 months after the intervention. RESULTS A statistically significant increase was found in the knowledge of caregivers about the cause, symptoms, and management of the disease. A statistically significant decrease occurred in the number of hospitalizations before and after the intervention but not in the number of visits to the ED. Multiple regression analysis found that none of the background variables were related to knowledge, ED visits, or hospitalizations. CLINICAL IMPLICATIONS Education and written materials written in a simple language that is understood by 5th-graders were beneficial in improving the knowledge of caregivers and in decreasing the number of hospitalizations of children with SCD.
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Paule I, Sassi H, Habibi A, Pham KP, Bachir D, Galactéros F, Girard P, Hulin A, Tod M. Population pharmacokinetics and pharmacodynamics of hydroxyurea in sickle cell anemia patients, a basis for optimizing the dosing regimen. Orphanet J Rare Dis 2011; 6:30. [PMID: 21619673 PMCID: PMC3118100 DOI: 10.1186/1750-1172-6-30] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/28/2011] [Indexed: 02/06/2023] Open
Abstract
Background Hydroxyurea (HU) is the first approved pharmacological treatment of sickle cell anemia (SCA). The objectives of this study were to develop population pharmacokinetic(PK)-pharmacodynamic(PD) models for HU in order to characterize the exposure-efficacy relationships and their variability, compare two dosing regimens by simulations and develop some recommendations for monitoring the treatment. Methods The models were built using population modelling software NONMEM VII based on data from two clinical studies of SCA adult patients receiving 500-2000 mg of HU once daily. Fetal hemoglobin percentage (HbF%) and mean corpuscular volume (MCV) were used as biomarkers for response. A sequential modelling approach was applied. Models were evaluated using simulation-based techniques. Comparisons of two dosing regimens were performed by simulating 10000 patients in each arm during 12 months. Results The PK profiles were described by a bicompartmental model. The median (and interindividual coefficient of variation (CV)) of clearance was 11.6 L/h (30%), the central volume was 45.3 L (35%). PK steady-state was reached in about 35 days. For a given dosing regimen, HU exposure varied approximately fivefold among patients. The dynamics of HbF% and MCV were described by turnover models with inhibition of elimination of response. In the studied range of drug exposures, the effect of HU on HbF% was at its maximum (median Imax was 0.57, CV was 27%); the effect on MCV was close to its maximum, with median value of 0.14 and CV of 49%. Simulations showed that 95% of the steady-state levels of HbF% and MCV need 26 months and 3 months to be reached, respectively. The CV of the steady-state value of HbF% was about 7 times larger than that of MCV. Simulations with two different dosing regimens showed that continuous dosing led to a stronger HbF% increase in some patients. Conclusions The high variability of response to HU was related in part to pharmacokinetics and to pharmacodynamics. The steady-state value of MCV at month 3 is not predictive of the HbF% value at month 26. Hence, HbF% level may be a better biomarker for monitoring HU treatment. Continuous dosing might be more advantageous in terms of HbF% for patients who have a strong response to HU. Trial Registration The clinical studies whose data are analysed and reported in this work were not required to be registered in France at their time. Both studies were approved by local ethics committees (of Mondor Hospital and of Kremlin-Bicetre Hospital) and written informed consent was obtained from each patient.
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Al-Saqladi AWM, Cipolotti R, Fijnvandraat K, Brabin BJ. Growth and nutritional status of children with homozygous sickle cell disease. ACTA ACUST UNITED AC 2009; 28:165-89. [PMID: 18727846 DOI: 10.1179/146532808x335624] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND Poor growth and under-nutrition are common in children with sickle cell disease (SCD). This review summarises evidence of nutritional status in children with SCD in relation to anthropometric status, disease severity, body composition, energy metabolism, micronutrient deficiency and endocrine dysfunction. METHODS A literature search was conducted on the Medline/PUBMED, SCOPUS, SciELO and LILACS databases to July 2007 using the keywords sickle cell combined with nutrition, anthropometry, growth, height and weight, body mass index, and specific named micronutrients. RESULTS Forty-six studies (26 cross-sectional and 20 longitudinal) were included in the final anthropometric analysis. Fourteen of the longitudinal studies were conducted in North America, the Caribbean or Europe, representing 78.8% (2086/2645) of patients. Most studies were observational with wide variations in sample size and selection of reference growth data, which limited comparability. There was a paucity of studies from Africa and the Arabian Peninsula, highlighting a large knowledge gap for low-resource settings. There was a consistent pattern of growth failure among affected children from all geographic areas, with good evidence linking growth failure to endocrine dysfunction, metabolic derangement and specific nutrient deficiencies. CONCLUSIONS The monitoring of growth and nutritional status in children with SCD is an essential requirement for comprehensive care, facilitating early diagnosis of growth failure and nutritional intervention. Randomised controlled trials are necessary to assess the potential benefits of nutritional interventions in relation to growth, nutritional status and the pathophysiology of the disease.
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El-Beshlawy A, Youssry I, El-Saidi S, El Accaoui R, Mansi Y, Makhlouf A, Taher A. Pulmonary hypertension in beta-thalassemia major and the role of L-carnitine therapy. Pediatr Hematol Oncol 2008; 25:734-43. [PMID: 19065439 DOI: 10.1080/08880010802244035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cardiac complications, such as pulmonary hypertension (PHT), are the leading cause of death in beta-thalassemia patients. L-Carnitine, due to its role in fatty acid oxidation, might help control the elevation in pulmonary artery systolic pressure (PASP). The objectives of this study were to assess the prevalence of PHT in beta-thalassemia major patients, identify clinical predictors for its development, and determine the potential effects of L-carnitine. In total, 32 patients with beta-thalassemia major were recruited; 16 age- and sex-matched children constituted the control group. Cardiac evaluation was performed by using echocardiography. The patients with PHT received 50 mg/kg/day L-carnitine orally for 3 months and were then reevaluated. Based on PASP, the patients were divided into group A without PHT and group B with PHT. The prevalence of PHT was 37.5%. The other echocardiographic measurements were not significantly different between groups A and B. PASP did not have any significant correlation with the following variables: age, total number of blood units received, splenic status, serum ferritin level, and ejection fraction. Following the administration of L-carnitine, there was a significant decrease in the mean PASP from 33.96 +/- 7.85 to 24.11 +/- 7.61. All cardiac dimensions decreased following L-carnitine, but the changes were not statistically significant. Even though beta-thalassemia major resulted in an elevation in the PASP in only a fraction of the patients, it seems to have an impact on the heart dimensions and function of all patients. No clinical predictors were identified. Oral administration of L-carnitine appears to significantly improve PASP.
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Kumkhaek C, Taylor JG, Zhu J, Hoppe C, Kato GJ, Rodgers GP. Fetal haemoglobin response to hydroxycarbamide treatment and sar1a promoter polymorphisms in sickle cell anaemia. Br J Haematol 2008; 141:254-9. [PMID: 18318767 PMCID: PMC2344124 DOI: 10.1111/j.1365-2141.2008.07045.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Accepted: 12/05/2007] [Indexed: 11/30/2022]
Abstract
The hydroxycarbamide (HC)-inducible small guanosine triphosphate (GTP)-binding protein, secretion-associated and RAS-related (SAR) protein has recently been shown to play a pivotal role in HBG induction and erythroid maturation by causing cell apoptosis and G1/S-phase arrest. Our preliminary analysis indicated that HC inducibility is transcriptionally regulated by elements within the SAR1A promoter. This study aimed to assess whether polymorphisms in the SAR1A promoter are associated with differences Hb F levels or HC therapeutic responses among sickle cell disease (SCD) patients. We studied 386 individuals with SCD comprised of 269 adults treated with or without HC and 117 newborns with SCD identified from a newborn screening program. Three previously unknown single nucleotide polymorphisms (SNPs) in the upstream 5'UTR (-809 C>T, -502 G>T and -385 C>A) were significantly associated with the fetal haemoglobin (HbF) response in Hb SS patients treated with HC (P < 0.05). In addition, four SNPs (rs2310991, -809 C>T, -385 C>A and rs4282891) were significantly associated with the change in absolute HbF after 2 years of treatment with HC. These data suggest that variation within SAR1A regulatory elements might contribute to inter-individual differences in regulation of HbF expression and patient responses to HC in SCD.
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Affiliation(s)
- Chutima Kumkhaek
- Molecular and Clinical Hematology Branch, NIDDK, NIH, Bethesda, MD, USA
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Romero MJ, Platt DH, Caldwell RB, Caldwell RW. Therapeutic use of citrulline in cardiovascular disease. ACTA ACUST UNITED AC 2007; 24:275-90. [PMID: 17214603 DOI: 10.1111/j.1527-3466.2006.00275.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
L-citrulline is the natural precursor of L-arginine, substrate for nitric oxide synthase (NOS) in the production of NO. Supplemental administration L-arginine has been shown to be effective in improving NO production and cardiovascular function in cardiovascular diseases associated with endothelial dysfunction, such as hypertension, heart failure, atherosclerosis, diabetic vascular disease and ischemia-reperfusion injury, but the beneficial actions do not endure with chronic therapy. Substantial intestinal and hepatic metabolism of L-arginine to ornithine and urea by arginase makes oral delivery very ineffective. Additionally, all of these disease states as well as supplemental L-arginine enhance arginase expression and activity, thus reducing the effectiveness of L-arginine therapy. In contrast, L-citrulline is not metabolized in the intestine or liver and does not induce tissue arginase, but rather inhibits its activity. L-citrulline entering the kidney, vascular endothelium and other tissues can be readily converted to L-arginine, thus raising plasma and tissue levels of L-arginine and enhancing NO production. Supplemental L-citrulline has promise as a therapeutic adjunct in disease states associated with L-arginine deficiencies.
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Affiliation(s)
- Maritza J Romero
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta GA, USA
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MESH Headings
- Acute Disease
- Adolescent
- Adult
- Age Factors
- Analgesics, Non-Narcotic/administration & dosage
- Analgesics, Non-Narcotic/therapeutic use
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/therapeutic use
- Anemia, Sickle Cell/complications
- Anemia, Sickle Cell/diagnosis
- Anemia, Sickle Cell/drug therapy
- Anemia, Sickle Cell/epidemiology
- Anemia, Sickle Cell/genetics
- Anemia, Sickle Cell/physiopathology
- Anemia, Sickle Cell/therapy
- Antibiotic Prophylaxis
- Antisickling Agents/administration & dosage
- Antisickling Agents/therapeutic use
- Blood Transfusion
- Child
- Child, Preschool
- Diagnosis, Differential
- Female
- Genotype
- Hematopoietic Stem Cell Transplantation
- Hospitalization
- Humans
- Hydroxyurea/administration & dosage
- Hydroxyurea/therapeutic use
- Ibuprofen/administration & dosage
- Ibuprofen/therapeutic use
- Immunization
- Infant
- Infant, Newborn
- Male
- Morphine/administration & dosage
- Morphine/therapeutic use
- Pain/diagnosis
- Pain/drug therapy
- Pain/etiology
- Pain Measurement
- Penicillins/administration & dosage
- Penicillins/therapeutic use
- Risk Factors
- Stroke/epidemiology
- Stroke/prevention & control
- Time Factors
- Treatment Outcome
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Affiliation(s)
- Rupa Redding-Lallinger
- Division of Hematology/Oncology, Department of Pediatrics, University of North Carolina, Chapel Hill, NC, USA
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Makis AC, Hatzimichael EC, Stebbing J. The genomics of new drugs in sickle cell disease. Pharmacogenomics 2006; 7:909-17. [PMID: 16981849 DOI: 10.2217/14622416.7.6.909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The quality of life of patients with sickle cell disease in developed countries has improved significantly over the past two decades. Currently available measures to prevent the painful crises and the complications of the disease include the use of penicillin prophylaxis, antipneumonococcal vaccine, folate administration, chronic red cell transfusions in patients with cerebrovascular disease, iron chelating agents, fetal hemoglobin-enhancing agents, such as hydroxyurea, decitabine and butyrate, drugs that augment the endogenous nitric oxide levels and agents that restore red cell dehydration. Sickle cell patients show a broad phenotypic expression and a great variability in treatment response. Genetic association studies, which attempt to link polymorphisms with certain disease phenotypes and drug response, are taking the first steps in aiding individualized therapy in sickle cell patients in order to enhance efficacy and reduce toxicity.
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Affiliation(s)
- Alexandros C Makis
- Department of Paediatrics, University Hospital of Ioannina, Ioannina, Greece.
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Abstract
Developments in the treatment of sickle cell disease (SCD) have not kept pace with advances in understanding the pathophysiology of this haemoglobinopathy. Drugs undergoing preclinical and clinical assessment for the therapy of these globin gene disorders are discussed in this article. Beginning with investigational agents for treatment of SCD as a whole, the discussion proceeds to drugs being developed for specific manifestations or iatrogenic complications. Despite being licensed in the USA, the prototype antisickling agent, hydroxycarbamide, has not attained worldwide clinical use because of concerns about long-term toxicity. The less toxic decitabine, which (as with hydroxycarbamide) increases fetal haemoglobin level, cannot be administered orally; therefore, the search continues for effective and safe antisickling drugs that can be taken orally. The naturally occurring benzaldehyde 5-hydroxymethyl-2-furfural has shown promising antisickling properties in vitro, and when administered to transgenic sickle mice. These effects are surpassed by the new synthetic pyridyl derivatives of benzaldehyde. Studies in humans with SCD are required to assess the clinical efficacy of these benzaldehydes. Niprisan, another antisickling agent with significant clinical efficacy and an attractive safety profile, is undergoing further development. The prospects of antiadhesion therapy in SCD are demonstrated by a recombinant protein containing the Fc fragment of IgG fused to the natural ligand for selectins: the conjugate significantly inhibited blood vessel occlusion in transgenic sickle mice. Whereas the orally administrable iron-chelating agent deferasirox is likely to increasingly take the place of desferioxamine (which can only be given parenterally), effective treatment of priapism in SCD remains a distressing challenge.
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MESH Headings
- Acetamides/pharmacology
- Acetamides/therapeutic use
- Anemia, Sickle Cell/complications
- Anemia, Sickle Cell/drug therapy
- Anemia, Sickle Cell/metabolism
- Anemia, Sickle Cell/therapy
- Animals
- Antihypertensive Agents/therapeutic use
- Antisickling Agents/pharmacology
- Antisickling Agents/therapeutic use
- Benzaldehydes/pharmacology
- Benzaldehydes/therapeutic use
- Benzoates/administration & dosage
- Benzoates/therapeutic use
- Carnitine/therapeutic use
- Cell Adhesion
- Deferasirox
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Etilefrine/therapeutic use
- Female
- Genetic Therapy/methods
- Hematopoietic Stem Cell Transplantation
- Humans
- Hydroxyurea/pharmacology
- Hydroxyurea/therapeutic use
- Hypertension, Pulmonary/drug therapy
- Hypertension, Pulmonary/etiology
- Iron Chelating Agents/administration & dosage
- Iron Chelating Agents/therapeutic use
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/pharmacology
- Membrane Glycoproteins/therapeutic use
- Potassium Channels, Calcium-Activated/antagonists & inhibitors
- Potassium Channels, Calcium-Activated/metabolism
- Priapism/drug therapy
- Priapism/etiology
- Recombinant Fusion Proteins/pharmacology
- Recombinant Fusion Proteins/therapeutic use
- Triazoles/administration & dosage
- Triazoles/therapeutic use
- Triphenylmethyl Compounds/pharmacology
- Triphenylmethyl Compounds/therapeutic use
- Vasoconstrictor Agents/therapeutic use
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Affiliation(s)
- Iheanyi Okpala
- St Thomas' Hospital, University of London, London SE1 7EH, UK.
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