1
|
Huang MC, Turner KJ, Vallant M, Robinson VG, Lu Y, Price CJ, Fennell TR, Silinski MA, Waidyanatha S, Ryan KR, Black SR, Fernando RA, McIntyre BS. Tolerability and age-dependent toxicokinetics following perinatal hydroxyurea treatment in Sprague Dawley rats. J Appl Toxicol 2020; 41:1007-1020. [PMID: 33241551 PMCID: PMC8144245 DOI: 10.1002/jat.4087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/17/2020] [Accepted: 09/22/2020] [Indexed: 11/11/2022]
Abstract
Hydroxyurea (HU) is a valuable therapy for individuals with sickle cell anemia. With increased use of HU in children and throughout their lives, it is important to understand the potential effects of HU therapy on their development and fertility. Thus, studies were conducted to identify appropriate doses to examine long‐term effects of prenatal and early postnatal HU exposure and to understand kinetics of HU at various life stages. Pregnant Sprague Dawley dams were administered HU (0–150 mg/kg/day) via oral gavage from gestation days 17 to 21 and during lactation. Pups were dosed with the same dose as their respective dam starting on postnatal day (PND) 10 and up to PND 34. There was minimal maternal toxicity, and no significant effects on littering at any dose of HU. Starting on ~PND 16, offspring displayed skin discoloration and alopecia at doses ≥75 mg/kg/day and lower body weight compared to controls at doses ≥100 mg/kg/day. Gestational transfer of HU was observed, but there was minimal evidence of lactational transfer. Our toxicokinetic studies suggest that the internal dose in offspring may be altered due to age, but not due to sex. The plasma area under the curve, a measure of systemic exposure, at doses tolerated by offspring was threefold to sevenfold lower than the internal therapeutic dose in humans. Therefore, strategies to establish clinically relevant exposures in animal studies are needed. Overall, these data are useful for the design of appropriate nonclinical studies in the future to evaluate the consequences of long‐term HU treatment starting in childhood. Increased use of hydroxyurea (HU) to treat sickle cell disease in children and throughout their lives augments the importance of understanding potential effects of HU on development and fertility. To inform the design of studies to evaluate long‐term safety of HU use in children, tolerability of prenatal and early postnatal HU treatment was evaluated in Sprague Dawley rats. Additionally, studies investigating gestational and lactational transfer of HU and how toxicokinetics of HU vary with age were conducted.
Collapse
Affiliation(s)
- Madelyn C Huang
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | | | - Molly Vallant
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Veronica G Robinson
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Yi Lu
- Social and Scientific Services, Durham, North Carolina, USA
| | | | | | | | - Suramya Waidyanatha
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Kristen R Ryan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | | | | | - Barry S McIntyre
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| |
Collapse
|
2
|
Mukosera GT, Liu T, Manaen M, Zhu L, Power G, Schroeder H, Blood AB. Deferoxamine produces nitric oxide under ferricyanide oxidation, blood incubation, and UV-irradiation. Free Radic Biol Med 2020; 160:458-470. [PMID: 32828952 PMCID: PMC11059783 DOI: 10.1016/j.freeradbiomed.2020.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/03/2020] [Accepted: 08/09/2020] [Indexed: 11/29/2022]
Abstract
Deferoxamine (DFO), an iron chelator, is used therapeutically for the removal of excess iron in multiple clinical conditions such as beta thalassemia and intracerebral hemorrhage. DFO is also used as an iron chelator and hypoxia-mimetic agent in in vivo and in vitro basic research. Here we unexpectedly discover DFO to be a nitric oxide (NO) precursor in experiments where it was intended to act as an iron chelator. Production of NO from aqueous solutions of DFO was directly observed by ozone-based chemiluminescence using a ferricyanide-based assay and was confirmed by electron paramagnetic resonance (EPR). DFO also produced NO following exposure to ultraviolet light, and its incubation with sheep adult and fetal blood resulted in considerable formation of iron nitrosyl hemoglobin, as confirmed by both visible spectroscopy and EPR. These results suggest that experiments using DFO can be confounded by concomitant production of NO, and offer new insight into some of DFO's unexplained clinical side effects such as hypotension.
Collapse
Affiliation(s)
- George T Mukosera
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA
| | - Taiming Liu
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA
| | - Meshach Manaen
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA
| | - Lingchao Zhu
- Department of Chemistry, University of California-Riverside 501 Big Springs Road, Riverside, CA 92521, USA
| | - Gordon Power
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA
| | - Hobe Schroeder
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA
| | - Arlin B Blood
- Lawrence D Longo Center for Perinatal Biology and Department of Pediatrics, Loma Linda University, 11175 Campus Street, Loma Linda, CA, 92354, USA.
| |
Collapse
|
3
|
Double-Blind Clinical Trial of Arginine Supplementation in the Treatment of Adult Patients with Sickle Cell Anaemia. Adv Hematol 2019; 2019:4397150. [PMID: 30853991 PMCID: PMC6378076 DOI: 10.1155/2019/4397150] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/22/2018] [Accepted: 01/15/2019] [Indexed: 12/21/2022] Open
Abstract
Background Sickle cell anaemia (SCA) is the most prevalent monogenic disease in Brazil. In SCA, haemoglobin S (HbS) is formed, which modifies red blood cell morphology. Intravascular haemolysis occurs, in which free Hb and free radicals degrade nitric oxide (NO) and release arginase, which reduces arginine levels. Because arginine is a substrate for NO formation, this decrease leads to reduced NO (vasodilator) synthesis. SCA treatment uses hydroxyurea (HU) to maintain high foetal haemoglobin (HbF) levels and reduces HbS to avoid haemolytic episodes. Objective To analyse the efficacy of L-arginine as an adjuvant in the treatment of SCA patients. Setting The State Blood Centre of Ceará, Brazil. Methods This was a randomized double-blind clinical study of adults with SCA with continuous use of HU at the State Blood Centre of Ceará. The clinical study enrolled 25 patients receiving HU + L-arginine (500 mg) and 25 patients receiving HU + placebo. The treatment was carried out over four months. Laboratory tests were performed to determine the levels of the following: (1) complete blood count; (2) nitrite + nitrate; (3) HbF; and (4) reticulocytes. The clinical experiments were performed by a haematologist. The main outcome measures were nitrite and pain. Results Statistical analysis showed that the levels of NO were increased in the study group, and there was also a reduction in pain frequency using a pain frequency scale by day, week, and month. The levels of nitrite plus nitrate in the group receiving placebo plus HU did not change among the times evaluated (38.27 ± 17.27 mg/L, 39.49 ± 12.84 mg/L, 34.45 ± 11.25 mg/L, p >0.05), but in the patients who received supplementation with L-arginine plus HU, a significant increase in nitrite plus nitrate levels was observed between M0 and M4 (36.55 ± 20.23 mg/L versus 48.64 ± 20.63 mg/L, p =0.001) and M2 and M4 (35.71 ± 15.11 mg/L versus 48.64 ± 20.63 mg/L, p <0.001). It is important to note that the increase in nitrite plus nitrate levels occurred only in the fourth month of follow-up of patients in the treatment group, showing that at least 4 months of supplementation with L-arginine is necessary to show an increase in these metabolites in the serum. Conclusion The use of L-arginine as a coadjuvant in the treatment of sickle cell anaemia may function as a potential tool for pain relief, consequently improving the life of patients.
Collapse
|
4
|
Bharti S, Choudhary M, Mohan B, Sharma SR, Ahmad K. Syntheses, crystal structures, DFT, molecular docking and inhibition studies of jack been urease by nickel (II) and copper (II) Schiff base complexes. INORG NANO-MET CHEM 2018. [DOI: 10.1080/24701556.2018.1503679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Sulakshna Bharti
- Department of Chemistry, National Institute of Technology Patna, Patna, Bihar, India
| | - Mukesh Choudhary
- Department of Chemistry, National Institute of Technology Patna, Patna, Bihar, India
| | - Bharti Mohan
- Department of Chemistry, National Institute of Technology Patna, Patna, Bihar, India
| | - S. R. Sharma
- Department of Chemistry, National Institute of Technology Patna, Patna, Bihar, India
| | - K. Ahmad
- Department of Chemistry, National Institute of Technology Patna, Patna, Bihar, India
| |
Collapse
|
5
|
Yahouédéhou SCMA, Adorno EV, da Guarda CC, Ndidi US, Carvalho SP, Santiago RP, Aleluia MM, de Oliveira RM, Gonçalves MDS. Hydroxyurea in the management of sickle cell disease: pharmacogenomics and enzymatic metabolism. THE PHARMACOGENOMICS JOURNAL 2018; 18:730-739. [DOI: 10.1038/s41397-018-0045-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/20/2018] [Accepted: 08/10/2018] [Indexed: 02/06/2023]
|
6
|
Sangeeta S, Ahmad K, Noorussabah N, Bharti S, Mishra M, Sharma S, Choudhary M. Synthesis, crystal structures, molecular docking and urease inhibition studies of Ni(II) and Cu(II) Schiff base complexes. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.11.062] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
7
|
Cui Y, Qiao L, Li Y, Jing H, Li Y, Wang Q. Synthesis, solid-state structures, and urease inhibition activities of new copper(II) complexes based on O,N,O-tridentate Schiff bases. J COORD CHEM 2016. [DOI: 10.1080/00958972.2016.1206199] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Yongming Cui
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| | - Lu Qiao
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| | - Yi Li
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| | - Hairui Jing
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| | - Yuguang Li
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| | - Qiang Wang
- Ministry of Education, Engineering Research Center for Clean Production of Textile Printing and Dyeing, Wuhan Textile University, Wuhan, PR China
| |
Collapse
|
8
|
Kosaryan M, Zafari M, Alipur A, Hedayatizadeh-Omran A. The Effect and Side Effect of Hydroxyurea Therapy on Patients With β-Thalassemia: A Systematic Review to December 2012. Hemoglobin 2014; 38:262-71. [DOI: 10.3109/03630269.2014.927770] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
9
|
Kovacic P. Hydroxyurea (therapeutics and mechanism): Metabolism, carbamoyl nitroso, nitroxyl, radicals, cell signaling and clinical applications. Med Hypotheses 2011; 76:24-31. [DOI: 10.1016/j.mehy.2010.08.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 08/03/2010] [Accepted: 08/08/2010] [Indexed: 10/19/2022]
|
10
|
Sassi H, Bachir D, Habibi A, Astier A, Galactéros F, Hulin A. No effect of CYP450 and P-glycoprotein on hydroxyurea in vitro metabolism. Fundam Clin Pharmacol 2010; 24:83-90. [DOI: 10.1111/j.1472-8206.2009.00723.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
11
|
Reisz JA, Bechtold E, King SB. Oxidative heme protein-mediated nitroxyl (HNO) generation. Dalton Trans 2010; 39:5203-12. [DOI: 10.1039/c000980f] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
12
|
Estiu G, Suárez D, Merz KM. Quantum mechanical and molecular dynamics simulations of ureases and Zn beta-lactamases. J Comput Chem 2007; 27:1240-62. [PMID: 16773613 DOI: 10.1002/jcc.20411] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Herein we briefly review theoretical contributions that have increased our understanding of the structure and function of metallo-beta-lactamases and ureases. Both are bimetallic metalloenzymes, with the former containing two zinc ions and the latter containing two nickel ions. We describe the use of several different methodologies, including quantum chemical calculations, molecular dynamic simulations, as well as mixed QM/MM approaches and how they have impacted our understanding of the structure and function of metallo-beta-lactamases and ureases.
Collapse
Affiliation(s)
- Guillermina Estiu
- Department of Chemistry, Quantum Theory Project, University of Florida, 2328 New Physics Building, P.O. Box 118435, Gainesville, Florida 32611-8435, USA
| | | | | |
Collapse
|
13
|
Cokic VP, Beleslin-Cokic BB, Noguchi CT, Schechter AN. Hydroxyurea increases eNOS protein levels through inhibition of proteasome activity. Nitric Oxide 2007; 16:371-8. [PMID: 17306993 DOI: 10.1016/j.niox.2007.01.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 01/04/2007] [Accepted: 01/08/2007] [Indexed: 11/16/2022]
Abstract
Recent reports have identified the proteasome as the primary degradation pathway for inducible, neuronal and endothelial nitric oxide synthase (NOS). We have demonstrated that hydroxyurea increased nitric oxide (NO) production in endothelial cells through phosphorylation of eNOS as a short-term effect. We find now that NO production in endothelial cells is dose-dependently stimulated by hydroxyurea, as well as both specific and non-specific proteasome inhibitors, as a long term effect. Prolonged treatment of primary human umbilical vein endothelial cells (HUVEC) with hydroxyurea was found to increase eNOS protein levels without an effect on eNOS mRNA levels, suggesting posttranscriptional control. We observed that the inhibitors of proteasomes that we tested also increased eNOS protein levels in HUVEC. In a proteasome assay, we showed that hydroxyurea inhibited protein degradation in a dose-dependent manner, in both purified 20S proteasome and HUVEC lysates. The NO production induced by hydroxyurea in endothelial cells appears to be mediated by long term posttranscriptional augmentation in eNOS levels via inhibition of the proteasome activity.
Collapse
Affiliation(s)
- Vladan P Cokic
- Laboratory of Experimental Hematology, Institute for Medical Research, Dr. Subotica 4, P.O. Box 102, 11129 Belgrade, Serbia.
| | | | | | | |
Collapse
|
14
|
Huang J, Yakubu M, Kim-Shapiro DB, King SB. Rat liver-mediated metabolism of hydroxyurea to nitric oxide. Free Radic Biol Med 2006; 40:1675-81. [PMID: 16632127 DOI: 10.1016/j.freeradbiomed.2006.01.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 12/13/2005] [Accepted: 01/03/2006] [Indexed: 01/18/2023]
Abstract
Hydroxyurea is an approved treatment for sickle cell disease. Oxidation of hydroxyurea results in the formation of nitric oxide (NO), which also has drawn considerable interest as a sickle cell disease therapy. Although patients on hydroxyurea demonstrate elevated levels of nitric oxide-derived metabolites, little information regarding the site or mechanism of the in vivo conversion of hydroxyurea to nitric oxide exists. Chemiluminescence detection experiments show the ability of crude rat liver homogenate to convert hydroxyurea to nitrite/nitrate, evidence for NO production. Nitrite/nitrate form at therapeutic concentrations of hydroxyurea in a clinically relevant time frame. Electron paramagnetic resonance (EPR) studies show the formation of iron nitrosyl complexes during this incubation and experiments with labeled hydroxyurea show the NO derives from the drug. Gas chromatography-mass spectrometry measurements indicate the hydrolysis of hydroxyurea to hydroxylamine in this system. Incubation of hydroxylamine with crude rat liver homogenate also generates nitrite/nitrate and iron nitrosyl complexes. A line of evidence including inhibitor studies, EPR spectroscopy, and nitrite/nitrate detection identifies catalase as a possible oxidant for the conversion of hydroxyurea to NO. These results reveal the ability of liver tissue to convert hydroxyurea to nitric oxide and provide insight into the metabolism of this drug.
Collapse
Affiliation(s)
- Jinming Huang
- Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA
| | | | | | | |
Collapse
|
15
|
Estiu G, Merz KM. Catalyzed decomposition of urea. Molecular dynamics simulations of the binding of urea to urease. Biochemistry 2006; 45:4429-43. [PMID: 16584179 PMCID: PMC2505355 DOI: 10.1021/bi052020p] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present the results of molecular dynamics simulations on the urea/urease system. The starting structure was prepared from the 2.0 A crystal structure of Benini et al. [(1999) Struct. Folding Des. 7, 205-216] of DAP-inhibited urease (PDB code ), and the trimeric structure (2479 residues) resulted in 180K atoms after solvation by water. The force field parameters were derived using the bonded model approach described by Hoops et al. [(1991) J. Am. Chem. Soc. 113, 8262-8270]. Three different systems were analyzed, each one modeling a different protonation pattern for the His320 and His219 residues. In each case, the three monomers of urease have been analyzed separately. The time-averaged structures observed in the three monomers suggest that urease could follow two different competitive mechanisms. A "protein-assisted proton transfer" mechanism points to Asp221 as crucial for catalysis. An "Asp-mediated proton transfer" involves the transfer of a proton from the bridging OH to an NH2 moiety of urea, assisted by Asp360 in the active site. The impact of the simulation results on our understanding of urease catalysis is discussed in detail.
Collapse
Affiliation(s)
- Guillermina Estiu
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
| | | |
Collapse
|
16
|
Burkitt MJ, Raafat A. Nitric oxide generation from hydroxyurea: significance and implications for leukemogenesis in the management of myeloproliferative disorders. Blood 2006; 107:2219-22. [PMID: 16282342 DOI: 10.1182/blood-2005-08-3429] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe use of myelosuppressive agents to reduce the risk of thrombosis in patients with polycythemia vera (PV) and essential thrombocythemia (ET) has been associated with an increased risk of transformation to acute myeloid leukemia (AML). Whereas chlorambucil, busulfan, and radiophosphorus (32P) have been demonstrated to increase the risk of transformation, the leukemogenic potential of hydroxyurea (HU) continues to be a matter of debate. Clinical studies have suggested that HU may cause a small increase in the risk of AML, but it has proven difficult to establish whether AML is actually caused by HU or arises during the natural progression of PV and ET. Reports that HU undergoes metabolic activation to species that induce mutation appear to support the notion that it is leukemogenic. Here, we suggest that the ability of HU to induce mutation in cell culture studies results from the generation of nitrogen dioxide via the autoxidation of nitric oxide, a product of HU metabolism. However, we argue that autoxidation would not occur in vivo, leading to the conclusion that generation of the mutagen nitrogen dioxide is peculiar to cell culture systems and has little relevance to the use of HU in the management of PV and ET.
Collapse
Affiliation(s)
- Mark J Burkitt
- Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood, Middlesex, HA6 2JR United Kingdom.
| | | |
Collapse
|
17
|
Abstract
Hydroxyurea is a relatively new treatment for sickle cell disease. A portion of hydroxyurea's beneficial effects may be mediated by nitric oxide, which has also drawn considerable interest as a sickle cell disease treatment. Patients taking hydroxyurea show a significant increase in iron nitrosyl hemoglobin and plasma nitrite and nitrate within 2 h of ingestion, providing evidence for the in vivo conversion of hydroxyurea to nitric oxide. Hydroxyurea reacts with hemoglobin to produce iron nitrosyl hemoglobin, nitrite, and nitrate, but these reactions do not occur fast enough to account for the observed increases in these species in patients taking hydroxyurea. This report reviews recent in vitro studies directed at better understanding the in vivo nitric oxide release from hydroxyurea in patients. Specifically, this report covers: (1) peroxidase-mediated formation of nitric oxide from hydroxyurea; (2) nitric oxide production after hydrolysis of hydroxyurea to hydroxylamine; and (3) the nitric oxide-producing structure-activity relationships of hydroxyurea. Results from these studies should provide a better understanding of the nitric oxide donor properties of hydroxyurea and guide the development of new hydroxyurea-derived nitric oxide donors as potential sickle cell disease therapies.
Collapse
Affiliation(s)
- S Bruce King
- Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA.
| |
Collapse
|