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Rabelo IB, Chiba AK, Moritz E, D'Amora P, Silva IDCG, Rodrigues CA, Barros MMO, Bordin JO. Metabolomic profile in patients with primary warm autoimmune haemolytic anaemia. Br J Haematol 2022; 201:140-149. [PMID: 36484101 DOI: 10.1111/bjh.18584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 11/16/2022] [Accepted: 11/20/2022] [Indexed: 12/13/2022]
Abstract
Autoimmune haemolytic anaemia (AIHA) is a rare clinical condition with immunoglobulin fixation on the surface of erythrocytes, with or without complement activation. The pathophysiology of AIHA is complex and multifactorial, presenting functional abnormalities of T and B lymphocytes that generate an imbalance between lymphocyte activation, immunotolerance and cytokine production that culminates in autoimmune haemolysis. In AIHA, further laboratory data are needed to predict relapse and refractoriness of therapy, and thus, prevent adverse side-effects and treatment-induced toxicity. The metabolomic profile of AIHA has not yet been described. Our group developed a cross-sectional study with follow-up to assess the metabolomic profile in these patients, as well as to compare the metabolites found depending on the activity and intensity of haemolysis. We analysed the plasma of 26 patients with primary warm AIHA compared to 150 healthy individuals by mass spectrometry. Of the 95 metabolites found in the patients with AIHA, four acylcarnitines, two phosphatidylcholines (PC), asymmetric dimethylarginine (ADMA) and three sphingomyelins were significantly increased. There was an increase in PC, spermine and spermidine in the AIHA group with haemolytic activity. The PC ae 34:3/PC ae 40:2 ratio, seen only in the 12-month relapse group, was a predictor of relapse with 81% specificity and 100% sensitivity. Increased sphingomyelin, ADMA, PC and polyamines in patients with warm AIHA can interfere in autoantigen and autoimmune recognition mechanisms in a number of ways (deficient action of regulatory T lymphocytes on erythrocyte recognition as self, negative regulation of macrophage nuclear factor kappa beta activity, perpetuation of effector T lymphocyte and antibody production against erythrocyte antigens). The presence of PC ae 34:3/PC ae 40:2 ratio as a relapse predictor can help in identifying cases that require more frequent follow-up or early second-line therapies.
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Affiliation(s)
- Iara B. Rabelo
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Akemi K. Chiba
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Elyse Moritz
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Paulo D'Amora
- Gynecology Department College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Ismael Dale C. G. Silva
- Gynecology Department College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Celso A. Rodrigues
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - Melca M. O. Barros
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
| | - José O. Bordin
- Clinical and Experimental Oncology Department, Haematology and Hemotherapy Division College of Medicine of the Federal University of São Paulo (EPM‐UNIFESP) São Paulo Brazil
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Dai D, Dai F, Chen J, Jin M, Li M, Hu D, Liu Z, Zhang Z, Xu F, Chen WH. Integrated multi-omics reveal important roles of gut contents in intestinal ischemia–reperfusion induced injuries in rats. Commun Biol 2022; 5:938. [PMID: 36085351 PMCID: PMC9463172 DOI: 10.1038/s42003-022-03887-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/08/2022] [Indexed: 12/13/2022] Open
Abstract
Intestinal ischemia–reperfusion (IIR) is a life-threatening clinical event with damaging signals whose origin and contents are unclear. Here we observe that IIR significantly affect the metabolic profiles of most organs by unbiased organ-wide metabolic analysis of gut contents, blood, and fifteen organs in rats (n = 29). Remarkably, correlations between gut content metabolic profiles and those of other organs are the most significant. Gut contents are also the only ones to show dynamic correlations during IIR. Additionally, according to targeted metabolomics analysis, several neurotransmitters are considerably altered in the gut during IIR, and displayed noteworthy correlations with remote organs. Likewise, metagenomics analysis (n = 35) confirm the effects of IIR on gut microbiota, and identify key species fundamental to the changes in gut metabolites, particularly neurotransmitters. Our multi-omics results establish key roles of gut contents in IIR induced remote injury and provide clues for future exploration. Die Dai et al. evaluate changes in the metabolomic and gut microbiome in response to experimental intestinal ischemia reperfusion (IIR) injury in rats. Their results provide further insight into how gut contents contribute to widespread injury in IIR patients.
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Ataga KI, Saraf SL, Derebail VK. The nephropathy of sickle cell trait and sickle cell disease. Nat Rev Nephrol 2022; 18:361-377. [PMID: 35190716 PMCID: PMC9832386 DOI: 10.1038/s41581-022-00540-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2022] [Indexed: 01/13/2023]
Abstract
Sickle cell syndromes, including sickle cell disease (SCD) and sickle cell trait, are associated with multiple kidney abnormalities. Young patients with SCD have elevated effective renal plasma flow and glomerular filtration rates, which decrease to normal ranges in young adulthood and subnormal levels with advancing age. The pathophysiology of SCD-related nephropathy is multifactorial - oxidative stress, hyperfiltration and glomerular hypertension are all contributing factors. Albuminuria, which is an early clinical manifestation of glomerular damage, is common in individuals with SCD. Kidney function declines more rapidly in individuals with SCD than in those with sickle cell trait or in healthy individuals. Multiple genetic modifiers, including APOL1, HMOX1, HBA1 and HBA2 variants are also implicated in the development and progression of SCD-related nephropathy. Chronic kidney disease and rapid decline in estimated glomerular filtration rate are associated with increased mortality in adults with SCD. Renin-angiotensin-aldosterone system inhibitors are the standard of care treatment for albuminuria in SCD, despite a lack of controlled studies demonstrating their long-term efficacy. Multiple studies of novel therapeutic agents are ongoing, and patients with SCD and kidney failure should be evaluated for kidney transplantation. Given the high prevalence and severe consequences of kidney disease, additional studies are needed to elucidate the pathophysiology, natural history and treatment of SCD-related nephropathy.
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Affiliation(s)
- Kenneth I Ataga
- Center for Sickle Cell Disease, University of Tennessee Health Scienter Center, Memphis, TN, USA.
| | - Santosh L Saraf
- Division of Hematology/Oncology, University of Illinois, Chicago, IL, USA
| | - Vimal K Derebail
- Division of Nephrology and Hypertension, University of North Carolina, Chapel Hill, NC, USA
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Bou-Fakhredin R, De Franceschi L, Motta I, Eid AA, Taher AT, Cappellini MD. Redox Balance in β-Thalassemia and Sickle Cell Disease: A Love and Hate Relationship. Antioxidants (Basel) 2022; 11:antiox11050967. [PMID: 35624830 PMCID: PMC9138068 DOI: 10.3390/antiox11050967] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 11/16/2022] Open
Abstract
β-thalassemia and sickle cell disease (SCD) are inherited hemoglobinopathies that result in both quantitative and qualitative variations in the β-globin chain. These in turn lead to instability in the generated hemoglobin (Hb) or to a globin chain imbalance that affects the oxidative environment both intracellularly and extracellularly. While oxidative stress is not among the primary etiologies of β-thalassemia and SCD, it plays a significant role in the pathogenesis of these diseases. Different mechanisms exist behind the development of oxidative stress; the result of which is cytotoxicity, causing the oxidation of cellular components that can eventually lead to cell death and organ damage. In this review, we summarize the mechanisms of oxidative stress development in β-thalassemia and SCD and describe the current and potential antioxidant therapeutic strategies. Finally, we discuss the role of targeted therapy in achieving an optimal redox balance.
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Affiliation(s)
- Rayan Bou-Fakhredin
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (R.B.-F.); (I.M.)
| | - Lucia De Franceschi
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, 37128 Verona, Italy;
| | - Irene Motta
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (R.B.-F.); (I.M.)
- UOC General Medicine, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Assaad A. Eid
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon;
| | - Ali T. Taher
- Division of Hematology-Oncology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon;
| | - Maria Domenica Cappellini
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (R.B.-F.); (I.M.)
- UOC General Medicine, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Correspondence:
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Martins SR, Toledo SLDO, da Silva AJ, Mendes FS, de Oliveira MM, Ferreira LGR, Dusse LMS, Carvalho MDG, Rios DRA, Alpoim PN, Pinheiro MDB. Endothelial dysfunction biomarkers in sickle cell disease: is there a role for ADMA and PAI-1? Ann Hematol 2021; 101:273-280. [PMID: 34665295 DOI: 10.1007/s00277-021-04695-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/10/2021] [Indexed: 01/26/2023]
Abstract
Within the spectrum of sickle cell disease (SCD) are sickle cell anemia (SCA), presence of hemoglobin SS (HbSS), hemoglobin SC disease (HbSC), and sickle cell β-thalassemia (Sβ-thal). Asymmetric dimethylarginine (ADMA) competitively inhibits the binding of arginine to NOS, reducing NO production. In patients with HbSS, increased levels of ADMA have been reported, as well as changes in many hemostatic biomarkers, including the plasminogen activator inhibitor type 1 (PAI-1). We hypothesized that high levels of ADMA and PAI-1 may be associated with more severe SCD. Thus, ADMA and PAI-1 levels were determined in 78 individuals including 38 adult patients with SCD and 40 control subjects. Higher levels of ADMA were shown in HbSS and Sβ-thal patients compared to controls. Concerning PAI-1, all patients showed high levels of PAI-1 compared to controls. As a role of NO in the pathogenesis of SCD has already been established, we concluded that high levels of ADMA should compromise, at least in part, NO synthesis, resulting in endothelial dysfunction. Elevated plasma levels of PAI-1 in all patients may indicate not only endothelial dysfunction but also a hypofibrinolytic state favoring thrombotic complications. Finally, high levels of ADMA and PAI-1 may be associated with more severe SCD.
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Affiliation(s)
- Suellen Rodrigues Martins
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil
| | - Sílvia Letícia de Oliveira Toledo
- Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil
| | - Aislander Junio da Silva
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil
| | - Fernanda Santos Mendes
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil
| | - Marina Mendes de Oliveira
- Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil.,Fundação Centro de Hematologia E Hemoterapia Do Estado de Minas Gerais, (Hemominas), Divinópolis, MG, Brazil
| | - Leticia Gonçalves Resende Ferreira
- Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil
| | - Luci Maria Sant'Ana Dusse
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil
| | - Maria das Graças Carvalho
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil.,Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil
| | - Danyelle Romana Alves Rios
- Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil
| | - Patrícia Nessralla Alpoim
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270901, Brazil.
| | - Melina de Barros Pinheiro
- Federal University of São João del-Rei (UFSJ), Campus Centro-Oeste Dona Lindu, Sebastião Gonçalves Coelho Street, 400, Building: D, Room: 308.1, ChanadourDivinópolis, MG, 35501-296, Brazil.
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Dembélé KC, Mintz T, Veyrat-Durebex C, Chabrun F, Chupin S, Tessier L, Simard G, Henrion D, Mirebeau-Prunier D, Chao de la Barca JM, Tharaux PL, Reynier P. Metabolomic Profiling of Plasma and Erythrocytes in Sickle Mice Points to Altered Nociceptive Pathways. Cells 2020; 9:cells9061334. [PMID: 32466566 PMCID: PMC7349104 DOI: 10.3390/cells9061334] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 12/26/2022] Open
Abstract
Few data-driven metabolomic approaches have been reported in sickle cell disease (SCD) to date. We performed a metabo-lipidomic study on the plasma and red blood cells of a steady-state mouse model carrying the homozygous human hemoglobin SS, compared with AS and AA genotypes. Among the 188 metabolites analyzed by a targeted quantitative metabolomic approach, 153 and 129 metabolites were accurately measured in the plasma and red blood cells, respectively. Unsupervised PCAs (principal component analyses) gave good spontaneous discrimination between HbSS and controls, and supervised OPLS-DAs (orthogonal partial least squares-discriminant analyses) provided highly discriminant models. These models confirmed the well-known deregulation of nitric oxide synthesis in the HbSS genotype, involving arginine deficiency and increased levels of dimethylarginines, ornithine, and polyamines. Other discriminant metabolites were newly evidenced, such as hexoses, alpha-aminoadipate, serotonin, kynurenine, and amino acids, pointing to a glycolytic shift and to the alteration of metabolites known to be involved in nociceptive pathways. Sharp remodeling of lysophosphatidylcholines, phosphatidylcholines, and sphingomyelins was evidenced in red blood cells. Our metabolomic study provides an overview of the metabolic remodeling induced by the sickle genotype in the plasma and red blood cells, revealing a biological fingerprint of altered nitric oxide, bioenergetics and nociceptive pathways.
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Affiliation(s)
- Klétigui Casimir Dembélé
- Faculté de Pharmacie, Université des Sciences, des Techniques et des Technologies de Bamako BP, Bamako 1805, Mali;
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
| | - Thomas Mintz
- Paris Cardiovascular Centre (PARCC), Institut National de la Santé et de la Recherche Médicale (INSERM), 75015 Paris, France;
| | - Charlotte Veyrat-Durebex
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1253, Université François Rabelais de Tours, 37000 Tours, France;
- Laboratoire de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire de Tours, 37000 Tours, France
| | - Floris Chabrun
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
| | - Stéphanie Chupin
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
| | - Lydie Tessier
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
| | - Gilles Simard
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
| | - Daniel Henrion
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
| | - Delphine Mirebeau-Prunier
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
| | - Juan Manuel Chao de la Barca
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
| | - Pierre-Louis Tharaux
- Paris Cardiovascular Centre (PARCC), Institut National de la Santé et de la Recherche Médicale (INSERM), 75015 Paris, France;
- Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
- Nephrology Division, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France
- Correspondence: (P.-L.T.); (P.R.)
| | - Pascal Reynier
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, 49933 Angers, France; (F.C.); (S.C.); (L.T.); (G.S.); (D.M.-P.); (J.M.C.d.l.B.)
- Unité Mixte de Recherche (UMR) MITOVASC, Centre National de la Recherche Scientifique (CNRS) 6015, Institut National de la Santé et de la Recherche Médicale (INSERM) U1083, Université d’Angers, 49933 Angers, France;
- Correspondence: (P.-L.T.); (P.R.)
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8
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Esse R, Barroso M, Tavares de Almeida I, Castro R. The Contribution of Homocysteine Metabolism Disruption to Endothelial Dysfunction: State-of-the-Art. Int J Mol Sci 2019; 20:E867. [PMID: 30781581 PMCID: PMC6412520 DOI: 10.3390/ijms20040867] [Citation(s) in RCA: 157] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/05/2019] [Accepted: 02/12/2019] [Indexed: 02/07/2023] Open
Abstract
Homocysteine (Hcy) is a sulfur-containing non-proteinogenic amino acid formed during the metabolism of the essential amino acid methionine. Hcy is considered a risk factor for atherosclerosis and cardiovascular disease (CVD), but the molecular basis of these associations remains elusive. The impairment of endothelial function, a key initial event in the setting of atherosclerosis and CVD, is recurrently observed in hyperhomocysteinemia (HHcy). Various observations may explain the vascular toxicity associated with HHcy. For instance, Hcy interferes with the production of nitric oxide (NO), a gaseous master regulator of endothelial homeostasis. Moreover, Hcy deregulates the signaling pathways associated with another essential endothelial gasotransmitter: hydrogen sulfide. Hcy also mediates the loss of critical endothelial antioxidant systems and increases the intracellular concentration of reactive oxygen species (ROS) yielding oxidative stress. ROS disturb lipoprotein metabolism, contributing to the growth of atherosclerotic vascular lesions. Moreover, excess Hcy maybe be indirectly incorporated into proteins, a process referred to as protein N-homocysteinylation, inducing vascular damage. Lastly, cellular hypomethylation caused by build-up of S-adenosylhomocysteine (AdoHcy) also contributes to the molecular basis of Hcy-induced vascular toxicity, a mechanism that has merited our attention in particular. AdoHcy is the metabolic precursor of Hcy, which accumulates in the setting of HHcy and is a negative regulator of most cell methyltransferases. In this review, we examine the biosynthesis and catabolism of Hcy and critically revise recent findings linking disruption of this metabolism and endothelial dysfunction, emphasizing the impact of HHcy on endothelial cell methylation status.
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Affiliation(s)
- Ruben Esse
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Madalena Barroso
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Isabel Tavares de Almeida
- Laboratory of Metabolism and Genetics, Faculty of Pharmacy, University of Lisbon, 1649-003 Lisbon, Portugal.
| | - Rita Castro
- Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, 1649-003 Lisbon, Portugal.
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, 1649-003 Lisbon, Portugal.
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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Elsherif L, Pathmasiri W, McRitchie S, Archer DR, Ataga KI. Plasma metabolomics analysis in sickle cell disease patients with albuminuria - an exploratory study. Br J Haematol 2018; 185:620-623. [PMID: 30198565 DOI: 10.1111/bjh.15592] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Laila Elsherif
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA
| | - Wimal Pathmasiri
- NIH Common Fund Eastern Regional Comprehensive Metabolomics Resource Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Susan McRitchie
- NIH Common Fund Eastern Regional Comprehensive Metabolomics Resource Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David R Archer
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Kenneth I Ataga
- Center for Sickle Cell Disease, University of Tennessee Health Science Center, Memphis, TN, USA
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10
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Haymann JP, Hammoudi N, Stankovic Stojanovic K, Galacteros F, Habibi A, Avellino V, Bartolucci P, Benzerara Y, Arlet JB, Djebbar M, Letavernier E, Grateau G, Tabibzadeh N, Girshovich A, Chaignon M, Girot R, Levy P, Lionnet F. Renin-angiotensin system blockade promotes a cardio-renal protection in albuminuric homozygous sickle cell patients. Br J Haematol 2017; 179:820-828. [DOI: 10.1111/bjh.14969] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/25/2017] [Indexed: 01/26/2023]
Affiliation(s)
- Jean-Philippe Haymann
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
- Sorbonne Universites UPMC Univ Paris 06; Paris France
- Institut National de la Sante et de la Recherche Medicale; UMR-S 1155; Paris France
| | - Nadjib Hammoudi
- Service de Cardiologie; Hôpital de la Pitie Salpetrière; Assistance Publique-Hopitaux de Paris; Paris France
- Institute of Cardiometabolism and Nutrition (ICAN); Paris France
| | | | - Frederic Galacteros
- Centre for Sickle Cell Disease; Hôpital Mondor; Assistance Publique-Hopitaux de Paris; Paris France
| | - Anoosha Habibi
- Centre for Sickle Cell Disease; Hôpital Mondor; Assistance Publique-Hopitaux de Paris; Paris France
| | - Virginie Avellino
- Centre for Sickle Cell Disease; Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Pablo Bartolucci
- Centre for Sickle Cell Disease; Hôpital Mondor; Assistance Publique-Hopitaux de Paris; Paris France
| | - Yahia Benzerara
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Jean-Benoit Arlet
- Centre for Sickle Cell Disease; Hôpital Européen Georges Pompidou; Assistance Publique-Hopitaux de Paris; Paris France
| | - Morad Djebbar
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Emmanuel Letavernier
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
- Sorbonne Universites UPMC Univ Paris 06; Paris France
- Institut National de la Sante et de la Recherche Medicale; UMR-S 1155; Paris France
| | - Gilles Grateau
- Centre for Sickle Cell Disease; Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Nathalie Tabibzadeh
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Alexei Girshovich
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Michel Chaignon
- Service d'Explorations Fonctionnelles Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Robert Girot
- Centre for Sickle Cell Disease; Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Pierre Levy
- Public Health Department; Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
| | - Francois Lionnet
- Centre for Sickle Cell Disease; Hôpital Tenon; Assistance Publique-Hopitaux de Paris; Paris France
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11
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Shilo NR, Morris CR. Pathways to pulmonary hypertension in sickle cell disease: the search for prevention and early intervention. Expert Rev Hematol 2017; 10:875-890. [PMID: 28817980 DOI: 10.1080/17474086.2017.1364989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Pulmonary hypertension (PH) develops in a significant number of patients with sickle cell disease (SCD), resulting in increased morbidity and mortality. This review focuses on PH pathophysiology, risk stratification, and new recommendations for screening and treatment for patients with SCD. Areas covered: An extensive PubMed literature search was performed. While the pathophysiology of PH in SCD is yet to be fully deciphered, it is known that the etiology is multifactorial; hemolysis, hypercoagulability, hypoxemia, ischemic-reperfusion injury, oxidative stress, and genetic susceptibility all contribute in varying degrees to endothelial dysfunction. Hemolysis, in particular, seems to play a key role by inciting an imbalance in the regulatory axis of nitric oxide and arginine metabolism. Systematic risk stratification starting in childhood based on clinical features and biomarkers that enable early detection is necessary. Multi-faceted, targeted interventions, before irreversible vasculopathy develops, will allow for improved patient outcomes and life expectancy. Expert commentary: Despite progress in our understanding of PH in SCD, clinically proven therapies remain elusive and additional controlled clinical trials are needed. Prevention of disease starts in childhood, a critical window for intervention. Given the complex and multifactorial nature of SCD, patients will ultimately benefit from combination therapies that simultaneously targets multiple mechanisms.
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Affiliation(s)
- Natalie R Shilo
- a Department of Pediatrics, Division of Pulmonary Medicine , University of Connecticut Heath Center , Farmington , CT , USA
| | - Claudia R Morris
- b Department of Pediatrics, Division of Pediatric Emergency Medicine, Emory-Children's Center for Cystic Fibrosis and Airways Disease Research , Emory University School of Medicine , Atlanta , GA , USA
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12
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Oztas Y, Yalcinkaya A. Oxidative alterations in sickle cell disease: Possible involvement in disease pathogenesis. World J Hematol 2017; 6:55-61. [DOI: 10.5315/wjh.v6.i3.55] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/25/2017] [Accepted: 05/22/2017] [Indexed: 02/05/2023] Open
Abstract
Sickle cell disease (SCD) is the first molecular disease in the literature. Although the structural alteration and dysfunction of the sickle hemoglobin (HbS) are well understood, the many factors modifying the clinical signs and symptoms of the disease are under investigation. Besides having an abnormal electrophoretic mobility and solubility, HbS is unstable. The autooxidation rate of the abnormal HbS has been reported to be almost two times of the normal. There are two more components of the oxidative damage in SCD: Free radical induced oxidative damage during vaso-occlusion induced ischemia-reperfusion injury and decreased antioxidant capacity in the erythrocyte and in the circulation. We will discuss the effects of oxidative alterations in the erythrocyte and in the plasma of SCD patients in this review.
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Morris CR, Hamilton-Reeves J, Martindale RG, Sarav M, Ochoa Gautier JB. Acquired Amino Acid Deficiencies: A Focus on Arginine and Glutamine. Nutr Clin Pract 2017; 32:30S-47S. [PMID: 28388380 DOI: 10.1177/0884533617691250] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nonessential amino acids are synthesized de novo and therefore not diet dependent. In contrast, essential amino acids must be obtained through nutrition since they cannot be synthesized internally. Several nonessential amino acids may become essential under conditions of stress and catabolic states when the capacity of endogenous amino acid synthesis is exceeded. Arginine and glutamine are 2 such conditionally essential amino acids and are the focus of this review. Low arginine bioavailability plays a pivotal role in the pathogenesis of a growing number of varied diseases, including sickle cell disease, thalassemia, malaria, acute asthma, cystic fibrosis, pulmonary hypertension, cardiovascular disease, certain cancers, and trauma, among others. Catabolism of arginine by arginase enzymes is the most common cause of an acquired arginine deficiency syndrome, frequently contributing to endothelial dysfunction and/or T-cell dysfunction, depending on the clinical scenario and disease state. Glutamine, an arginine precursor, is one of the most abundant amino acids in the body and, like arginine, becomes deficient in several conditions of stress, including critical illness, trauma, infection, cancer, and gastrointestinal disorders. At-risk populations are discussed together with therapeutic options that target these specific acquired amino acid deficiencies.
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Affiliation(s)
- Claudia R Morris
- 1 Department of Pediatrics, Division of Pediatric Emergency Medicine, Emory-Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jill Hamilton-Reeves
- 2 Department of Dietetics and Nutrition, University of Kansas, Kansas City, Kansas, USA
| | - Robert G Martindale
- 3 Department of Surgery, Oregon Health and Science University, Portland, Oregon, USA
| | - Menaka Sarav
- 4 Department of Medicine, Division of Nephrology, Northshore University Health System, University of Chicago, Chicago, Illinois, USA
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14
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Bakshi N, Morris CR. The role of the arginine metabolome in pain: implications for sickle cell disease. J Pain Res 2016; 9:167-75. [PMID: 27099528 PMCID: PMC4821376 DOI: 10.2147/jpr.s55571] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sickle cell disease (SCD) is the most common hemoglobinopathy in the US, affecting approximately 100,000 individuals in the US and millions worldwide. Pain is the hallmark of SCD, and a subset of patients experience pain virtually all of the time. Of interest, the arginine metabolome is associated with several pain mechanisms highlighted in this review. Since SCD is an arginine deficiency syndrome, the contribution of the arginine metabolome to acute and chronic pain in SCD is a topic in need of further attention. Normal arginine metabolism is impaired in SCD through various mechanisms that contribute to endothelial dysfunction, vaso-occlusion, pulmonary complications, risk of leg ulcers, and early mortality. Arginine is a semiessential amino acid that serves as a substrate for protein synthesis and is the precursor to nitric oxide (NO), polyamines, proline, glutamate, creatine, and agmatine. Since arginine is involved in multiple metabolic processes, a deficiency of this amino acid has the potential to disrupt many cellular and organ functions. NO is a potent vasodilator that is depleted in SCD and may contribute to vaso-occlusive pain. As the obligate substrate for NO production, arginine also plays a mechanistic role in SCD-related pain, although its contribution to pain pathways likely extends beyond NO. Low global arginine bioavailability is associated with pain severity in both adults and children with SCD as well as other non-SCD pain syndromes. Preliminary clinical studies of arginine therapy in SCD demonstrate efficacy in treating acute vaso-occlusive pain, as well as leg ulcers and pulmonary hypertension. Restoration of arginine bioavailability through exogenous supplementation of arginine is, therefore, a promising therapeutic target. Phase II clinical trials of arginine therapy for sickle-related pain are underway and a Phase III randomized controlled trial is anticipated in the near future.
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Affiliation(s)
- Nitya Bakshi
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA; Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Claudia R Morris
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA; Department of Emergency Medicine, Emory University School of Medicine, Atlanta, GA, USA; Emory-Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, USA; Pediatric Emergency Medicine, Children's Healthcare of Atlanta, Atlanta, GA, USA
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15
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Voskou S, Aslan M, Fanis P, Phylactides M, Kleanthous M. Oxidative stress in β-thalassaemia and sickle cell disease. Redox Biol 2015; 6:226-239. [PMID: 26285072 PMCID: PMC4543215 DOI: 10.1016/j.redox.2015.07.018] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 12/21/2022] Open
Abstract
Sickle cell disease and β-thalassaemia are inherited haemoglobinopathies resulting in structural and quantitative changes in the β-globin chain. These changes lead to instability of the generated haemoglobin or to globin chain imbalance, which in turn impact the oxidative environment both intracellularly and extracellularly. The ensuing oxidative stress and the inability of the body to adequately overcome it are, to a large extent, responsible for the pathophysiology of these diseases. This article provides an overview of the main players and control mechanisms involved in the establishment of oxidative stress in these haemoglobinopathies.
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Affiliation(s)
- S Voskou
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - M Aslan
- Akdeniz University, Faculty of Medicine, Department of Medical Biochemistry, Antalya, Turkey
| | - P Fanis
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - M Phylactides
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
| | - M Kleanthous
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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Owusu-Ansah A, Choi SH, Petrosiute A, Letterio JJ, Huang AYC. Triterpenoid inducers of Nrf2 signaling as potential therapeutic agents in sickle cell disease: a review. Front Med 2014; 9:46-56. [PMID: 25511620 DOI: 10.1007/s11684-015-0375-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 09/12/2014] [Indexed: 01/06/2023]
Abstract
Sickle cell disease (SCD) is an inherited disorder of hemoglobin in which the abnormal hemoglobin S polymerizes when deoxygenated. This polymerization of hemoglobin S not only results in hemolysis and vasoocclusion but also precipitates inflammation, oxidative stress and chronic organ dysfunction. Oxidative stress is increasingly recognized as an important intermediate in these pathophysiological processes and is therefore an important target for therapeutic intervention. The transcription factor nuclear erythroid derived-2 related factor 2 (Nrf2) controls the expression of anti-oxidant enzymes and is emerging as a protein whose function can be exploited with therapeutic intent. This review article is focused on triterpenoids that activate Nrf2, and their potential for reducing oxidative stress in SCD as an approach to prevent organ dysfunction associated with this disease. A brief overview of oxidative stress in the clinical context of SCD is accompanied by a discussion of several pathophysiological mechanisms contributing to oxidative stress. Finally, these mechanisms are then related to current management strategies in SCD that are either utilized currently or under evaluation. The article concludes with a perspective on the potential of the various therapeutic interventions to reduce oxidative stress and morbidity associated with SCD.
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Affiliation(s)
- Amma Owusu-Ansah
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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Morris CR. Alterations of the arginine metabolome in sickle cell disease: a growing rationale for arginine therapy. Hematol Oncol Clin North Am 2014; 28:301-21. [PMID: 24589268 DOI: 10.1016/j.hoc.2013.11.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Low global arginine bioavailability (GAB) is associated with numerous complications of SCD including early mortality. Mechanisms of arginine dysregulation involve a complex paradigm of excess activity of the arginine-consuming enzyme arginase, elevated levels of asymmetric dimethylarginine, altered intracellular arginine transport, and nitric oxide synthase dysfunction. Restoration of GAB through exogenous supplementation is therefore, a promising therapeutic target. Studies of arginine therapy demonstrate efficacy in treating patients with leg ulcers, pulmonary hypertension risk, and pain. Co-administration with hydroxyurea increases levels of nitrite and fetal hemoglobin. Addressing the alterations in the arginine metabolome may result in new strategies for treatment of SCD.
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Affiliation(s)
- Claudia R Morris
- Division of Emergency Medicine, Department of Pediatrics, Emory-Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, 1645 Tullie Circle Northeast, Atlanta, GA 30329, USA.
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18
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Weinberg JB, Yeo TW, Mukemba JP, Florence SM, Volkheimer AD, Wang H, Chen Y, Rubach M, Granger DL, Mwaikambo ED, Anstey NM. Dimethylarginines: endogenous inhibitors of nitric oxide synthesis in children with falciparum malaria. J Infect Dis 2014; 210:913-22. [PMID: 24620026 DOI: 10.1093/infdis/jiu156] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Nitric oxide (NO) bioavailability is impaired in children and adults with severe falciparum malaria (SM). Asymmetric-dimethylarginine (ADMA) limits NO production by inhibiting NO synthase and is increased in adult SM. The role of ADMA in the pathogenesis of childhood SM is unknown. METHODS We studied Tanzanian children ages 4-8 years with malaria. Plasma levels of arginine, arginase, cell-free hemoglobin, ADMA, symmetric-dimethylarginine (SDMA), histidine-rich protein-2, and angiopoietin-2 were measured. RESULTS ADMA was low in children with SM relative to controls. Nevertheless, arginine and arginine:ADMA ratios were very low in SM. SDMA was high in children with SM. With treatment, arginine and the arginine:ADMA ratio normalized, but SDMA did not. Arginine:ADMA ratios, but not arginine, were significantly and inde-pendent-ly inversely associated with lactate and angiopoietin-2. Plasma arginase was not elevated in those with malaria, and plasma free hemoglobin was elevated only in patients with cerebral malaria. CONCLUSIONS In contrast to adults, plasma ADMA is reduced in SM in children, but hypoargininemia is more severe. Arginine bioavailability (reflected by low arginine:ADMA ratios) is therefore comparably low in SM in children as in adults. Therapies to increase NO bioavailability in malaria may be useful as adjunctive treatment of severe malaria in children.
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Affiliation(s)
| | - Tsin W Yeo
- Menzies School of Health Research and Charles Darwin University, Australia
| | | | | | | | - Hao Wang
- Menzies School of Health Research and Charles Darwin University, Australia
| | - Youwei Chen
- Duke University and V.A. Medical Centers, Durham, North Carolina
| | - Matthew Rubach
- Duke University and V.A. Medical Centers, Durham, North Carolina
| | | | | | - Nicholas M Anstey
- Menzies School of Health Research and Charles Darwin University, Australia
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19
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Gomez E, Morris CR. Asthma management in sickle cell disease. BIOMED RESEARCH INTERNATIONAL 2013; 2013:604140. [PMID: 24324967 PMCID: PMC3842053 DOI: 10.1155/2013/604140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/05/2013] [Accepted: 09/13/2013] [Indexed: 01/19/2023]
Abstract
Asthma is a common comorbid factor in sickle cell disease (SCD). However, the incidence of asthma in SCD is much higher than expected compared to rates in the general population. Whether "asthma" in SCD is purely related to genetic and environmental factors or rather is the consequence of the underlying hemolytic and inflammatory state is a topic of recent debate. Regardless of the etiology, hypoxemia induced by bronchoconstriction and inflammation associated with asthma exacerbations will contribute to a cycle of sickling and subsequent complications of SCD. Recent studies confirm that asthma predisposes to complications of SCD such as pain crises, acute chest syndrome, and stroke and is associated with increased mortality. Early recognition and aggressive standard of care management of asthma may prevent serious pulmonary complications and reduce mortality. However, data regarding the management of asthma in SCD is very limited. Clinical trials are needed to evaluate the effectiveness of current asthma therapy in patients with SCD and coincident asthma, while mechanistic studies are needed to delineate the underlying pathophysiology.
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Affiliation(s)
- Esteban Gomez
- Department of Hematology-Oncology, Children's Hospital & Research Center Oakland, Oakland, CA 94609, USA
| | - Claudia R. Morris
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Emory University School of Medicine, 1645 Tullie Circle, NE, Atlanta, GA 30329, USA
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20
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El-Shanshory M, Badraia I, Donia A, Abd El-hameed F, Mabrouk M. Asymmetric dimethylarginine levels in children with sickle cell disease and its correlation to tricuspid regurgitant jet velocity. Eur J Haematol 2013; 91:55-61. [DOI: 10.1111/ejh.12114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2013] [Indexed: 01/26/2023]
Affiliation(s)
- Mohamed El-Shanshory
- Department of Pediatrics; Faculty of Medicine; University of Tanta; Tanta; Egypt
| | - Ibrahim Badraia
- Department of Pediatrics; Faculty of Medicine; University of Tanta; Tanta; Egypt
| | - Amr Donia
- Department of Pediatrics; Faculty of Medicine; University of Tanta; Tanta; Egypt
| | - Faten Abd El-hameed
- Department of Pediatrics; Faculty of Medicine; University of Tanta; Tanta; Egypt
| | - Mokhtar Mabrouk
- Department of Pharmaceutical Chemistry; Faculty of Pharmacy; University of Tanta; Tanta; Egypt
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21
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Morris CR, Kuypers FA, Lavrisha L, Ansari M, Sweeters N, Stewart M, Gildengorin G, Neumayr L, Vichinsky EP. A randomized, placebo-controlled trial of arginine therapy for the treatment of children with sickle cell disease hospitalized with vaso-occlusive pain episodes. Haematologica 2013; 98:1375-82. [PMID: 23645695 DOI: 10.3324/haematol.2013.086637] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Painful episodes of vaso-occlusion are the leading cause of hospitalizations and emergency department visits in sickle cell disease, and are associated with increased mortality. Low nitric oxide bioavailability contributes to vasculopathy in sickle cell disease. Since arginine is the obligate substrate for nitric oxide production, and an acute deficiency is associated with pain, we hypothesized that arginine may be a beneficial treatment for pain related to sickle cell disease. Thirty-eight children with sickle cell disease hospitalized for 56 episodes of pain were randomized into this double-blinded placebo-controlled trial. Patients received L-arginine (100 mg/kg tid) or placebo for 5 days or until discharge. A significant reduction in total parenteral opioid use by 54% (1.9 ± 2.0 mg/kg versus 4.1 ± 4.1 mg/kg, P=0.02) and lower pain scores at discharge (1.9 ± 2.4 versus 3.9 ± 2.9, P=0.01) were observed in the treatment arm compared to the placebo one. There was no significant difference in hospital length of stay (4.1 ± 01.8 versus 4.8 ± 2.5 days, P=0.34), although a trend favored the arginine arm, and total opioid use was strongly correlated with the duration of the admission (r=0.86, P<0.0001). No drug-related adverse events were observed. Arginine therapy represents a novel intervention for painful vaso-occlusive episodes. A reduction of narcotic use by >50% is remarkable. Arginine is a safe and inexpensive intervention with narcotic-sparing effects that may be a beneficial adjunct to standard therapy for sickle cell-related pain in children. A large multi-center trial is warranted in order to confirm these observations.
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Affiliation(s)
- Claudia R Morris
- Department of Pediatrics, Division of Emergency Medicine, Emory-Children's Center for Developmental Lung Biology, Emory University School of Medicine, Atlanta, GA, USA.
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Rafikov R, Rafikova O, Aggarwal S, Gross C, Sun X, Desai J, Fulton D, Black SM. Asymmetric dimethylarginine induces endothelial nitric-oxide synthase mitochondrial redistribution through the nitration-mediated activation of Akt1. J Biol Chem 2012; 288:6212-26. [PMID: 23255608 DOI: 10.1074/jbc.m112.423269] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have recently demonstrated that asymmetric dimethylarginine (ADMA) induces the translocation of endothelial nitric-oxide synthase (eNOS) to the mitochondrion via a mechanism that requires protein nitration. Thus, the goal of this study was elucidate how eNOS redistributes to mitochondria and to identify the nitrated protein responsible for this event. Our data indicate that exposure of pulmonary arterial endothelial cells to ADMA enhanced eNOS phosphorylation at the Akt1-dependent phosphorylation sites Ser(617) and Ser(1179). Mutation of these serine residues to alanine (S617A and S1179A) inhibited nitration-mediated eNOS translocation to the mitochondria, whereas the phosphormimic mutations (S617D and S1179D) exhibited increased mitochondrial redistribution in the absence of ADMA. The overexpression of a dominant-negative Akt1 also attenuated ADMA-mediated eNOS mitochondrial translocation. Furthermore, ADMA enhanced Akt1 nitration and increased its activity. Mass spectrometry identified a single nitration site in Akt1 located at the tyrosine residue (Tyr(350)) located within the client-binding domain. Replacement of Tyr(350) with phenylalanine abolished peroxynitrite-mediated eNOS translocation to mitochondria. We also found that in the absence of ADMA, eNOS translocation decreased mitochondrial oxygen consumption and superoxide production without altering cellular ATP level. This suggests that under physiologic conditions, eNOS translocation enhances mitochondria coupling. In conclusion, we have identified a new mechanism by which eNOS translocation to mitochondria is regulated by the phosphorylation of eNOS at Ser(617) and Ser(1179) by Akt1 and that this is enhanced when Akt1 becomes nitrated at Tyr(350).
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Affiliation(s)
- Ruslan Rafikov
- Pulmonary Disease Program, Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia 30912, USA
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Raval JS, Wearden PD, Orr RA, Kiss JE. Plasma exchange in a 13-year-old male with acute intravascular hemolysis and acute kidney injury after placement of a ventricular assist device. J Clin Apher 2012; 27:274-7. [DOI: 10.1002/jca.21236] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 05/21/2012] [Indexed: 01/26/2023]
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Musicki B, Liu T, Sezen SF, Burnett AL. Targeting NADPH oxidase decreases oxidative stress in the transgenic sickle cell mouse penis. J Sex Med 2012; 9:1980-7. [PMID: 22620981 DOI: 10.1111/j.1743-6109.2012.02798.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Sickle cell disease (SCD) is a state of chronic vasculopathy characterized by endothelial dysfunction and increased oxidative stress, but the sources and mechanisms responsible for reactive oxygen species (ROS) production in the penis are unknown. AIMS We evaluated whether SCD activates NADPH oxidase, induces endothelial nitric oxide synthase (eNOS) uncoupling, and decreases antioxidants in the SCD mouse penis. We further tested the hypothesis that targeting NADPH oxidase decreases oxidative stress in the SCD mouse penis. METHODS SCD transgenic (sickle) mice were used as an animal model of SCD. Hemizygous (hemi) mice served as controls. Mice received an NADPH oxidase inhibitor apocynin (10 mM in drinking water) or vehicle. Penes were excised at baseline for molecular studies. Markers of oxidative stress (4-hydroxy-2-nonenal [HNE]), sources of ROS (eNOS uncoupling and NADPH oxidase subunits p67(phox) , p47(phox) , and gp91(phox) ), and enzymatic antioxidants (superoxide dismutase [SOD]1, SOD2, catalase, and glutathione peroxidase-1 [GPx1]) were measured by Western blot in penes. MAIN OUTCOME MEASURES Sources of ROS, oxidative stress, and enzymatic antioxidants in the SCD penis. RESULTS Relative to hemi mice, SCD increased (P<0.05) protein expression of NADPH oxidase subunits p67(phox) , p47(phox) , and gp91(phox) , 4-HNE-modified proteins, induced eNOS uncoupling, and reduced Gpx1 expression in the penis. Apocynin treatment of sickle mice reversed (P<0.05) the abnormalities in protein expressions of p47(phox) , gp91(phox) (but not p67(phox) ) and 4-HNE, but only slightly (P>0.05) prevented eNOS uncoupling in the penis. Apocynin treatment of hemi mice did not affect any of these parameters. CONCLUSION NADPH oxidase and eNOS uncoupling are sources of oxidative stress in the SCD penis; decreased GPx1 further contributes to oxidative stress. Inhibition of NADPH oxidase upregulation decreases oxidative stress, implying a major role for NADPH oxidase as a ROS source and a potential target for improving vascular function in the SCD mouse penis.
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Affiliation(s)
- Biljana Musicki
- Department of Urology, The Johns Hopkins University, Baltimore, MD 21287, USA.
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25
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Caplin B, Leiper J. Endogenous nitric oxide synthase inhibitors in the biology of disease: markers, mediators, and regulators? Arterioscler Thromb Vasc Biol 2012; 32:1343-53. [PMID: 22460557 DOI: 10.1161/atvbaha.112.247726] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The asymmetric methylarginines inhibit nitric oxide synthesis in vivo by competing with L-arginine at the active site of nitric oxide synthase. High circulating levels of asymmetric dimethylarginine predict adverse outcomes, specifically vascular events but there is now increasing experimental and epidemiological evidence that these molecules, and the enzymes that regulate this pathway, play a mechanistic role in cardiovascular diseases. Recent data have provided insight into the impact of altered levels of these amino acids in both humans and rodents, however these reports also suggest a simplistic approach based on measuring, and modulating circulating asymmetric dimethylarginine alone is inadequate. This review outlines the basic biochemistry and physiology of endogenous methylarginines, examines both the experimental and observational evidence for a role in disease pathogenesis, and examines the potential for therapeutic regulation of these molecules.
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Affiliation(s)
- Ben Caplin
- Centre for Nephrology, UCL Medical School, Royal Free Campus 2nd Floor, Rowland Hill St, London NW3 2PF.
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Davids M, van Hell AJ, Visser M, Nijveldt RJ, van Leeuwen PAM, Teerlink T. Role of the human erythrocyte in generation and storage of asymmetric dimethylarginine. Am J Physiol Heart Circ Physiol 2012; 302:H1762-70. [PMID: 22367507 DOI: 10.1152/ajpheart.01205.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Proteolytic activity in whole blood may lead to release of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA). We investigated the role of the human erythrocyte in storage and generation of ADMA in healthy controls (n = 36) and critically ill patients (n = 38). Both free and total (sum of free and protein-incorporated) ADMA were measured. Upon incubation of intact erythrocytes with extracellular ADMA (0 to 40 μmol/l), equilibrium between intra- and extracellular ADMA was reached within 3 h. Compared with controls, patients had significantly higher basal concentrations of ADMA in plasma (0.88 ± 0.75 vs. 0.41 ± 0.07 μmol/l) and erythrocytes (1.28 ± 0.55 vs. 0.57 ± 0.14 μmol/l). Intracellular and plasma ADMA were significantly correlated in the patient group only (r = 0.834). Upon lysis, followed by incubation at 37°C for 2 h, free ADMA increased sevenfold (to 8.60 ± 3.61 μmol/l in patients and 3.90 ± 0.78 μmol/l in controls). In lysates of controls, free ADMA increased further to 9.85 ± 1.35 μmol/l after 18 h. Total ADMA was 15.43 ± 2.44 μmol/l and did not change during incubation. The increase of free ADMA during incubation corresponded to substantial release of ADMA from the erythrocytic protein-incorporated pool (21.9 ± 4.6% at 2 h and 60.8 ± 7.6% at 18 h). ADMA was released from proteins other than hemoglobin, which only occurred after complete lysis and was blocked by combined inhibition of proteasomal and protease activity. Neither intact nor lysed erythrocytes mediated degradation of free ADMA. We conclude that intact erythrocytes play an important role in storage of ADMA, whereas upon erythrocyte lysis large amounts of free ADMA are generated by proteolysis of methylated proteins, which may affect plasma levels in hemolysis-associated diseases.
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Affiliation(s)
- Mariska Davids
- Metabolic Laboratory, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
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Deonikar P, Kavdia M. Low micromolar intravascular cell-free hemoglobin concentration affects vascular NO bioavailability in sickle cell disease: a computational analysis. J Appl Physiol (1985) 2012; 112:1383-92. [PMID: 22223452 DOI: 10.1152/japplphysiol.01173.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In sickle cell disease, the changes in RBC morphology destabilize the red blood cell (RBC) membrane and lead to hemolysis. Several experimental and clinical studies have associated intravascular hemolysis with pulmonary hypertension in sickle cell disease. Cell-free hemoglobin (Hb) from intravascular hemolysis has high affinity for nitrixc oxide (NO) and can affect the NO bioavailability in the sickle cell disease, which may eventually lead to pulmonary hypertension. To study the effects of intravascular hemolysis related cell-free Hb concentrations on NO bioavailability, we developed a two-dimensional mathematical model of NO biotransport in 50-μm arteriole under steady-state sickle cell disease conditions. We analyzed the effects of flow-dependent NO production and axial and radial transport of NO, a recently reported much lower NO-RBC reaction rate constant, and cell-free layer thickness on NO biotransport. Our results show that the presence of cell-free Hb concentrations as low as 0.5 μM results in an approximately three- to sevenfold reduction in the predicted smooth muscle cell NO concentrations compared with those under physiological conditions. In addition, increasing the diffusional resistance for NO in vascular lumen from cell-free layer or reducing NO-RBC reaction rate did not improve the NO bioavailability at the smooth muscle cell layer significantly for cell-free Hb concentrations ≥1 μM. These results suggest that lower NO bioavailability due to low micromolar cell-free Hb can disturb NO homeostasis and cause insufficient bioavailability at the smooth muscle cell layer. Our results supports the hypothesis that hemolysis-associated reduction in NO bioavailability may play a role in the development of pathophysiological complications like pulmonary hypertension in sickle cell disease that are observed in several clinical and experimental studies.
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Affiliation(s)
- Prabhakar Deonikar
- Department of Biomedical Engineering, Wayne State University, 5050 Anthony Wayne Dr., Detroit, MI 48202, USA.
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Hoppe C, Kuypers F, Larkin S, Hagar W, Vichinsky E, Styles L. A pilot study of the short-term use of simvastatin in sickle cell disease: effects on markers of vascular dysfunction. Br J Haematol 2011; 153:655-63. [PMID: 21477202 DOI: 10.1111/j.1365-2141.2010.08480.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sickle cell disease (SCD) is characterized by progressive vascular injury and its pathophysiology is strikingly similar to that of atherosclerosis. Statins decrease inflammation and improve endothelial function in cardiovascular disease, but their effect in SCD is not known. In this pilot study, we examined the safety and effect of short-term simvastatin on biomarkers of vascular dysfunction in SCD. We treated 26 SCD patients with simvastatin, 20 or 40 mg/d, for 21 d. Plasma nitric oxide metabolites (NOx), C-reactive protein (CRP), interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), tissue factor (TF) and vascular endothelial growth factor (VEGF) were analyzed and responses to simvastatin were compared between the two treatment groups. Simvastatin increased NOx levels by 23% in the low-dose (P =0·01) and 106% in the moderate-dose (P =0·01) groups, and by 52% overall (P=0·0008). CRP decreased similarly in both dose groups and by 68% overall (P =0·02). Levels of IL-6 decreased by 50% (P=0·04) and 71% (P<0·05) in the low- and moderate-dose groups, respectively. Simvastatin had no effect on VEGF, VCAM1 or TF. Simvastatin was well-tolerated and safe. Our preliminary findings showing a dose-related effect of simvastatin on levels of NOx, CRP and IL-6 suggest a potential therapeutic role for simvastatin in SCD.
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Affiliation(s)
- Carolyn Hoppe
- Department of Haematology/Oncology, Children's Hospital & Research Center Oakland, 747 52nd Street, Oakland, CA 94609, USA.
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Leiper J, Nandi M. The therapeutic potential of targeting endogenous inhibitors of nitric oxide synthesis. Nat Rev Drug Discov 2011; 10:277-91. [DOI: 10.1038/nrd3358] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Wolf C, Lorenzen JM, Stein S, Tsikas D, Störk S, Weidemann F, Ertl G, Anker SD, Bauersachs J, Thum T. Urinary asymmetric dimethylarginine (ADMA) is a predictor of mortality risk in patients with coronary artery disease. Int J Cardiol 2010; 156:289-94. [PMID: 21159392 DOI: 10.1016/j.ijcard.2010.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 10/27/2010] [Accepted: 11/20/2010] [Indexed: 01/26/2023]
Abstract
BACKGROUND Asymmetric dimethylarginine (ADMA) causes endothelial dysfunction by inhibiting endothelial nitric oxide synthase. Elevated ADMA plasma levels comprise a major risk factor for coronary artery disease (CAD) and predict coronary events. ADMA is metabolised by dimethylarginine dimethylaminohydrolases (DDAHs) to citrulline and dimethylamine (DMA) and is partly excreted unchanged via the kidney. Unlike circulating ADMA, very little is known about urinary ADMA and DMA concentrations and a predictive value in CAD patients. METHODS AND RESULTS Seventy-seven consecutive patients admitted to hospital because of stable angina (mean age 65.9 ± 1.1 years) were enrolled and followed-up for 28 [1-28] months. All patients underwent cardiac catheterization and were divided into patients with no CAD or 1-3-vessel disease (CAD 1-3). Urinary ADMA levels (corrected for creatinine excretion) were lower in severely diseased patients (CAD 3, p<0.05) whereas the DMA/ADMA ratio was significantly increased (p<0.05 CAD 3 vs. CAD 0). In a stepwise multivariate regression analysis the ADMA/creatinine ratio correlated with cardiac function (r=0.5, p<0.0001) and LDL concentrations (r=0.27, p=0.01). A total of 12 patients died during follow-up, 9 due to cardiovascular causes. Importantly, low urinary ADMA concentrations predicted future cardiovascular death (p<0.01) and overall death (p<0.05). CONCLUSION In CAD patients low urinary ADMA concentrations are associated with impaired cardiac function and predict cardiovascular as well as all-cause mortality. The potential clinical value of urinary ADMA as a new biomarker for the diagnosis of CAD or cardiac dysfunction is intriguing, but warrants further studies.
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Affiliation(s)
- Christian Wolf
- Institut für Molekulare und Translationale Therapiestrategien (IMTTS), Medizinische Hochschule, Hannover, Germany
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Landburg P, Teerlink T, Biemond B, Brandjes D, Muskiet F, Duits A, Schnog J. Plasma asymmetric dimethylarginine concentrations in sickle cell disease are related to the hemolytic phenotype. Blood Cells Mol Dis 2010; 44:229-32. [DOI: 10.1016/j.bcmd.2010.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/21/2010] [Indexed: 01/26/2023]
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Potential utility of full-spectrum antioxidant therapy, citrulline, and dietary nitrate in the management of sickle cell disease. Med Hypotheses 2010; 74:1055-8. [PMID: 20089363 DOI: 10.1016/j.mehy.2009.12.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 12/16/2009] [Indexed: 01/26/2023]
Abstract
There is considerable evidence that oxidative stress and a loss of nitric oxide bioactivity are key mediators of the vasculopathies associated with sickle cell disease. A comprehensive nutraceutical strategy for mitigating the contribution of oxidative stress to pathogenesis - dubbed "full-spectrum antioxidant therapy" - may have utility in this syndrome. This strategy entails concurrent administration of phycocyanobilin - a phytochemical richly supplied by spirulina, shown to inhibit NADPH oxidase in a manner analogous to its chemical relatives biliverdin and bilirubin; high-dose folate - recently shown to quench peroxynitrite-derived radicals and restore coupling of NO synthase; N-acetylcysteine - for boosting intracellular glutathione levels; and a phase 2 inducer such as lipoic acid - to further promote glutathione synthesis while increasing expression of antioxidant enzymes. Suboptimal endothelial arginine levels, reflecting increased plasma arginase activity and elevated ADMA, contribute to the loss of NO bioactivity in sickle cell disease; supplementation with the arginine precursor citrulline may ameliorate this defect. Increased intakes of plant-derived nitrate have the potential to diminish the quenching of NO by plasma hemoglobin in sickle cell patients, while boosting systemic NO production independent of NO synthase activity. In addition to the well-documented utility of hydroxyurea - possibly a suboptimal strategy for life-long therapy owing to its mutagenic activity - rational pharmaceutical options for managing sickle cell disease include pentoxifylline and phosphodiesterase 5 inhibitors such as sildenafil.
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Abboud MR, Musallam KM. Sickle Cell Disease at the Dawn of the Molecular Era. Hemoglobin 2009; 33 Suppl 1:S93-S106. [DOI: 10.3109/03630260903347617] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
The breakdown of senescent or defective red blood cells releases red cell contents, especially haemoglobin, which scavenges nitric oxide (NO) and decomposes to haem and free iron. These are potent oxidants, all of which have promoted the evolution of inducible and vasculoprotective compensatory pathways to rapidly clear and detoxify haemoglobin, haem and iron. Chronic haemolytic red cell disorders as diverse as sickle cell disease, thalassaemia, unstable haemoglobinopathy, cytoskeletal defects and enzymopathies have been linked to a clinical constellation of pulmonary hypertension, priapism, leg ulceration and possibly cerebrovascular disease and thrombosis. Besides free haemoglobin, haemolysis has been associated with extracellular arginase that limits substrate availability to NO synthase, endogenous inhibitors of NO synthase activity, and inappropriate activation of haemostatic pathways. This article reviews the haemolytic disorders that have been reported to manifest vascular complications, and explores the speculative possibility that haemolysis mediates some of the vascular complications of inflammation and diabetes.
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Abstract
Sickle cell disease (SCD) is associated with a high incidence of ischemic stroke. SCD is characterized by hemolytic anemia, resulting in reduced nitric oxide-bioavailability, and by impaired cerebrovascular hemodynamics. Cerebrovascular CO2 responsiveness is nitric oxide dependent and has been related to an increased stroke risk in microvascular diseases. We questioned whether cerebrovascular CO2 responsiveness is impaired in SCD and related to hemolytic anemia. Transcranial Doppler-determined mean cerebral blood flow velocity (V(mean)), near-infrared spectroscopy-determined cerebral oxygenation, and end-tidal CO2 tension were monitored during normocapnia and hypercapnia in 23 patients and 16 control subjects. Cerebrovascular CO2 responsiveness was quantified as Delta% V(mean) and Deltamicromol/L cerebral oxyhemoglobin, deoxyhemoglobin, and total hemoglobin per mm Hg change in end-tidal CO2 tension. Both ways of measurements revealed lower cerebrovascular CO2 responsiveness in SCD patients versus controls (V(mean), 3.7, 3.1-4.7 vs 5.9, 4.6-6.7 Delta% V(mean) per mm Hg, P < .001; oxyhemoglobin, 0.36, 0.14-0.82 vs 0.78, 0.61-1.22 Deltamicromol/L per mm Hg, P = .025; deoxyhemoglobin, 0.35, 0.14-0.67 vs 0.58, 0.41-0.86 Deltamicromol/L per mm Hg, P = .033; total-hemoglobin, 0.13, 0.02-0.18 vs 0.23, 0.13-0.38 Deltamicromol/L per mm Hg, P = .038). Cerebrovascular CO2 responsiveness was not related to markers of hemolytic anemia. In SCD patients, impaired cerebrovascular CO2 responsiveness reflects reduced cerebrovascular reserve capacity, which may play a role in pathophysiology of stroke.
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Circulating endothelial cells: A potential parameter of organ damage in sickle cell anemia? Blood Cells Mol Dis 2009; 43:63-7. [DOI: 10.1016/j.bcmd.2009.02.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 02/13/2009] [Accepted: 02/20/2009] [Indexed: 01/09/2023]
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Abstract
Asthma is a common comorbidity in sickle cell disease (SCD) with a reported prevalence of 30-70%. The high frequency of asthma in this population cannot be attributed to genetic predisposition alone, and likely reflects in part, the contribution of overlapping mechanisms shared between these otherwise distinct disorders. There is accumulating evidence that dysregulated arginine metabolism and in particular, elevated arginase activity contributes to pulmonary complications in SCD. Derangements of arginine metabolism are also emerging as newly appreciated mechanism in both asthma and pulmonary hypertension independent of SCD. Patients with SCD may potentially be at risk for an asthma-like condition triggered or worsened by hemolysis-driven release of erythrocyte arginase and low nitric oxide bioavailability, in addition to classic familial asthma. Mechanisms that contributed to asthma are complex and multifactorial, influenced by genetic polymorphisms as well as environmental and infectious triggers. Given the association of asthma with inflammation, oxidative stress and hypoxemia, factors known to contribute to a vasculopathy in SCD, and the consequences of these factors on sickle erythrocytes, comorbid asthma would likely contribute to a vicious cycle of sickling and subsequent complications of SCD. Indeed a growing body of evidence documents what should come as no surprise: Asthma in SCD is associated with acute chest syndrome, stroke, pulmonary hypertension, and early mortality, and should therefore be aggressively managed based on established National Institutes of Health Guidelines for asthma management. Barriers to appropriate asthma management in SCD are discussed as well as strategies to overcome these obstacles in order to provide optimal care.
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Affiliation(s)
- Claudia R Morris
- Department of Emergency Medicine, Children's Hospital and Research Center Oakland, Oakland, California 94609, USA.
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Morris CR, Gladwin MT, Kato GJ. Nitric oxide and arginine dysregulation: a novel pathway to pulmonary hypertension in hemolytic disorders. Curr Mol Med 2009; 8:620-32. [PMID: 18991648 DOI: 10.2174/156652408786241447] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Secondary pulmonary hypertension (PH) is emerging as one of the leading causes of mortality and morbidity in patients with hemolytic anemias such as sickle cell disease (SCD) and thalassemia. Impaired nitric oxide (NO) bioavailability represents the central feature of endothelial dysfunction, and is a major factor in the pathophysiology of PH. Inactivation of NO correlates with hemolytic rate and is associated with the erythrocyte release of cell-free hemoglobin, which consumes NO directly, and the simultaneous release of the arginine-metabolizing enzyme arginase, which limits bioavailability of the NO synthase substrate arginine during the process of intravascular hemolysis. Rapid consumption of NO is accelerated by oxygen radicals that exists in both SCD and thalassemia. A dysregulation of arginine metabolism contributes to endothelial dysfunction and PH in SCD, and is strongly associated with prospective patient mortality. The central mechanism responsible for this metabolic disorder is enhanced arginine turnover, occurring secondary to enhanced plasma arginase activity. This is consistent with a growing appreciation of the role of excessive arginase activity in human diseases, including asthma and pulmonary arterial hypertension. New treatments aimed at improving arginine and NO bioavailability through arginase inhibition, suppression of hemolytic rate, oral arginine supplementation, or use of NO donors represent potential therapeutic strategies for this common pulmonary complication of hemolytic disorders.
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Affiliation(s)
- Claudia R Morris
- Department of Emergency Medicine, Children's Hospital & Research Center Oakland, Oakland, CA 94609, USA.
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Billecke SS, D'Alecy LG, Platel R, Whitesall SE, Jamerson KA, Perlman RL, Gadegbeku CA. Blood content of asymmetric dimethylarginine: new insights into its dysregulation in renal disease. Nephrol Dial Transplant 2008; 24:489-96. [PMID: 18796436 DOI: 10.1093/ndt/gfn500] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Plasma asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is significantly elevated in patients with kidney disease and is a potential risk factor for cardiovascular disease. Here, we tested whether human whole blood (WB), as in rodent blood, can accumulate free ADMA and whether this accumulation is a function of disease burden. METHODS In 16 healthy control subjects (CO), 18 patients with ESRD and 18 matched hypertensive patients with normal renal function (HTN), we compared using high-pressure liquid chromatography baseline plasma and WB supernatant (WBSUP) ADMA and symmetrical dimethylarginine (SDMA) concentrations and accumulation during a 5-h incubation. We measured protein turnover in incubated WBSUP to determine if proteolytic processes drive ADMA accumulation. RESULTS Elevated plasma ADMA was confirmed in ESRD and HTN populations while basal WBSUP ADMA was significantly higher in ESRD subjects than controls (P = 0.05 versus CO; P = 0.02 versus HTN). Plasma SDMA followed a similar pattern. Incubation of WBSUP resulted in ADMA release from protein-incorporated stores while SDMA was unaffected. ADMA accumulation in ESRD samples was significantly greater than that in HTN (P = 0.03). CO and HTN men showed significantly greater ADMA accumulation than women (P = 0.01 and P = 0.003, respectively) but no gender difference was observed in the ESRD group (P = 0.26). ADMA accumulation correlated with ex vivo protein turnover (R = 0.76, P < 0.0001). CONCLUSIONS Human blood is capable of releasing physiologically significant quantities of ADMA via proteolytic pathways. Dysregulated ADMA release from WB reservoirs may contribute to the distinctly high plasma ADMA levels in ESRD populations.
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Affiliation(s)
- Scott S Billecke
- University of Michigan Medical School, Simpson Memorial Institute, Rm 310, 102 Observatory Road, Ann Arbor, MI 48109-5725, USA
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Landburg PP, Teerlink T, Muskiet FAJ, Duits AJ, Schnog JJB. Plasma concentrations of asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, are elevated in sickle cell patients but do not increase further during painful crisis. Am J Hematol 2008; 83:577-9. [PMID: 18383318 DOI: 10.1002/ajh.21184] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, are elevated in the clinically asymptomatic state of sickle cell disease (SCD). However, the role of ADMA during vaso-occlusive complications has not been defined. ADMA concentrations were determined in HbSS (n = 43) and HbSC (n = 25) patients with healthy blood donors (HbAA) as controls. In the clinically asymptomatic state ADMA concentrations were elevated in sickle cell patients as compared to healthy controls (HbSS 0.70 micromol/L, HbSC 0.54 micromol/L, HbAA 0.39 micromol/L) (P < 0.001). Yet plasma ADMA concentrations did not increase further at presentation with a painful crisis implicating no role of primary importance during vaso-occlusive crises.
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Affiliation(s)
- Precious P Landburg
- Immunology Laboratory Department, Red Cross Blood Bank Foundation Curaçao, Curaçao, Netherlands Antilles
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Kato GJ, Wang Z, Machado RF, Blackwelder WC, Taylor JG, Hazen SL. Endogenous nitric oxide synthase inhibitors in sickle cell disease: abnormal levels and correlations with pulmonary hypertension, desaturation, haemolysis, organ dysfunction and death. Br J Haematol 2008; 145:506-13. [PMID: 19344390 DOI: 10.1111/j.1365-2141.2009.07658.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pulmonary hypertension (PH) in patients with sickle cell disease (SCD) is linked to intravascular haemolysis, impaired nitric oxide bioavailability, renal dysfunction, and early mortality. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthases (NOS), is associated with vascular disease in other populations. We determined the plasma concentrations for several key arginine metabolites and their relationships to clinical variables in 177 patients with SCD and 29 control subjects: ADMA, symmetric dimethylarginine (SDMA), NG-monomethyl L-arginine (L-NMMA), N-omega-hydroxy-L-arginine (NOHA), arginine and citrulline. The median ADMA was significantly higher in SCD than controls (0.94 micromol/l vs. 0.31 micromol/l, P < 0.001). Patients with homozygous SCD had a remarkably lower ratio of arginine to ADMA (50 micromol/l vs. 237, P < 0.001). ADMA correlated with markers of haemolysis, low oxygen saturation and soluble adhesion molecules. PH was associated with high levels of ADMA and related metabolites. Higher ADMA level was associated with early mortality, remaining significant in a multivariate analysis. Subjects with homozygous SCD have high systemic levels of ADMA, associated with PH and early death, implicating ADMA as a functional NOS inhibitor in these patients. These defects and others converge on the nitric oxide pathway in homozygous SCD with vasculopathy.
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Affiliation(s)
- Gregory J Kato
- Critical Care Medicine Department, Clinical Center, NHLBI, NIH, Bethesda, MD 20892-1476, USA.
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Morris CR. Mechanisms of vasculopathy in sickle cell disease and thalassemia. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2008; 2008:177-185. [PMID: 19074078 DOI: 10.1182/asheducation-2008.1.177] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Many mechanisms contribute to the complex pathophysiology of sickle cell disease (SCD), with dysfunction of the vascular endothelium as a unifying theme. Specifically, hemolysis-associated low arginine and nitric oxide (NO) bioavailability, amplified by NO synthase uncoupling, elevated arginase activity, superoxide production, oxidative stress, accumulation of arginine analogs such as asymmetric dimethylarginine, ischemia-reperfusion injury, inflammation, apolipoprotein A-1 depletion, and a hypercoagulable state are significant mechanisms contributing to endothelial dysfunction. Genetic polymorphisms also influence disease severity. Clearly the variable spectrum of disease is the consequence of multiple events and genetic susceptibility that go beyond the occurrence of a single amino acid substitution in the beta globin chain of hemoglobin. Recent studies begin to demonstrate overlap among these seemingly unrelated processes. Impaired NO bioavailability represents the central feature of endothelial dysfunction, and is a common denominator in the pathogenesis of vasculopathy in SCD. The consequences of decreased NO bioavailability include endothelial cell activation, upregulation of the potent vasoconstrictor endothelin-1, vasoconstriction, platelet activation, increased tissue factor, and activation of coagulation, all of which ultimately translate into the clinical manifestations of SCD. Evidence supporting vasculopathy subphenotypes in SCD, including pulmonary hypertension, priapism, cutaneous leg ulceration, and stroke, will be reviewed and relevance to other hemolytic disorders including the thalassemia syndromes will be considered.
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Affiliation(s)
- Claudia R Morris
- Department of Emergency Medicine, Children's Hospital & Research Center Oakland, Oakland, CA 94609, USA.
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Teerlink T. HPLC analysis of ADMA and other methylated l-arginine analogs in biological fluids. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 851:21-9. [PMID: 16931194 DOI: 10.1016/j.jchromb.2006.07.024] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 07/11/2006] [Accepted: 07/14/2006] [Indexed: 02/07/2023]
Abstract
Post-translational methylation of arginine residues in proteins leads to generation of N(G)-monomethylarginine (MMA) and both symmetric and asymmetric dimethylarginine (SDMA and ADMA), that are released into the cytosol upon proteolysis. Both MMA and ADMA are inhibitors of nitric oxide synthase and especially elevated levels of ADMA are associated with endothelial dysfunction and cardiovascular disease. Plasma concentrations of ADMA and SDMA are very low, typically between 0.3 and 0.8 microM, making their quantification by HPLC an analytical challenge. Sample preparation usually involves a cleanup step by solid-phase extraction on cation-exchange columns followed by derivatization of amino acids into fluorescent adducts. Because ADMA and SDMA concentrations in healthy subjects show a very narrow distribution, with a between-subject variability of 13% for ADMA and 19% for SDMA, very low imprecision is an essential assay feature. Procedures for sample cleanup, derivatization, and chromatographic separation of arginine and its methylated analogs are the main topics of this review. In addition, important aspects of method validation, pre-analytical factors, and reference values are discussed.
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Affiliation(s)
- Tom Teerlink
- Metabolic Laboratory, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands.
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Abstract
PURPOSE OF REVIEW Sickle cell disease and beta-thalassemia major are clinically significant hereditary anemias that elicit worldwide attention due to the frequency and severity of these disorders. Historically, most children who inherited these disorders died in the first decade of life. Recently, however, supportive care has extended lifespan through the fifth decade of life and beyond, with survival through early adulthood now indistinguishable from those unaffected by these disorders. As a result, chronic health impairments that significantly reduce the quality of life such as pulmonary hypertension and the consequences of transfusional iron overload have become principal challenges. RECENT FINDINGS We focus on important recent advances that are very likely to alter the nature of supportive care of these disorders or make it possible to identify prospectively high-risk patients who might benefit from novel therapies or even curative treatment in the form of hematopoietic cell transplantation. The availability of the latter, traditionally constrained by the requirement of a human leukocyte antigen-identical sibling donor, is very likely to be broadened as results after unrelated donor hematopoietic cell transplantation improve. SUMMARY In this review, several areas that are very likely to have a significant impact in the management of patients who inherit these disorders are discussed.
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Affiliation(s)
- Claudia R Morris
- Children's Hospital & Research Center Oakland, Oakland, CA 94609, USA
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Verhoeven MO, Hemelaar M, Teerlink T, Kenemans P, van der Mooren MJ. Effects of intranasal versus oral hormone therapy on asymmetric dimethylarginine in healthy postmenopausal women: a randomized study. Atherosclerosis 2006; 195:181-8. [PMID: 17084844 DOI: 10.1016/j.atherosclerosis.2006.09.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 08/30/2006] [Accepted: 09/27/2006] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Oral estrogens reduce asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, and an independent risk factor for cardiovascular disease. This study was conducted to compare the effect on ADMA between intranasal and oral 17beta-estradiol (E2) combined with norethisterone (acetate) (NET(A)) administration in postmenopausal women. METHODS In a two-center, randomized, double-blind, comparative study 90 healthy postmenopausal women (age 56.6+/-4.7 years) received daily continuous combined intranasal E2/NET 175 microg/275 microg (n=47) or oral E2/NETA 1 mg/0.5 mg (n=43) for one year. At baseline, week 12 and 52, plasma concentrations of ADMA, arginine and symmetric dimethylarginine (SDMA) were measured by high-performance liquid chromatography. RESULTS Oral E2/NETA reduced ADMA concentrations (-7.4%; 95% confidence interval (CI) -10.4 to -4.4%), while intranasal E2/NET had no effect (-0.8%; 95% CI -3.7 to 2.1%) after 52 weeks. In both groups, arginine was transiently decreased compared to baseline at week 12 (intranasal: -6.1%; 95% CI -9.1 to -3.0%; oral: -6.5%; 95% CI -10.9 to -2.1%). Only oral E2/NETA reduced SDMA concentrations. CONCLUSIONS Oral administration of E2/NETA reduced ADMA and SDMA concentrations, whereas intranasal administration did not. Both treatments transiently reduced arginine. The decrease in ADMA by oral estrogens could be a key phenomenon in the modulation of nitric oxide synthesis by postmenopausal hormone therapy.
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Affiliation(s)
- Marieke O Verhoeven
- Project Aging Women and the Institute for Cardiovascular Research-Vrije Universiteit, Department of Obstetrics & Gynecology, VU University Medical Center, Amsterdam, The Netherlands
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Billecke SS, Kitzmiller LA, Northrup JJ, Whitesall SE, Kimoto M, Hinz AV, D'Alecy LG. Contribution of whole blood to the control of plasma asymmetrical dimethylarginine. Am J Physiol Heart Circ Physiol 2006; 291:H1788-96. [PMID: 16632550 DOI: 10.1152/ajpheart.00066.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The endogenous nitric oxide (NO) synthase (NOS) inhibitor asymmetrical dimethylarginine (ADMA) is elevated in many patients and may contribute to the initiation and progression of their disease. While some mechanistic pathways have been identified, tissue-specific contributions to ADMA control remain unclear. We sought to determine if whole blood (WB) could participate in ADMA control ex vivo. Anesthetized male Sprague-Dawley rats underwent exsanguinations, and WB preparations were incubated at 37°C for 5 h. ADMA and symmetrical dimethylarginine were analyzed by high-pressure liquid chromatography. Incubation of lysed red blood cell (RBC) supernatant yielded a significant decrease in ADMA that was blocked by 4124W, a synthetic inhibitor of dimethylarginine dimethylaminohydrolase, the only reported enzyme to hydrolyze ADMA. Hydrolysis of ADMA was diminished by addition of physiologically relevant concentrations of zinc (i.e., 20 μM). Conversely, when rat WB or WB supernatant was incubated at 37°C, it liberated quantities of free ADMA (1–2 μM) that in vivo would likely have pathological consequences. Addition of arginine methyltransferase inhibitors to these incubations did not reduce ADMA release, indicating no dominant role for active protein methylation during these incubations. This ADMA liberation was significantly reduced by addition of protease inhibitors, indicating a dependence on peptide bond hydrolysis. Total ADMA (protein incorporated plus free) was determined by acid hydrolysis and found to be 43.18 ± 4.79 μM in WB with ∼95% of this in RBCs. These ex vivo data demonstrate the potential of blood to control the NO-NOS system by modulating free ADMA.
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Affiliation(s)
- Scott S Billecke
- 7744 Medical Sciences Bldg. II, Dept. of Molecular and Integrative Physiology, Univ. of Michigan Medical School, Ann Arbor, MI 48109-0622, USA.
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Kielstein JT, Donnerstag F, Gasper S, Menne J, Kielstein A, Martens-Lobenhoffer J, Scalera F, Cooke JP, Fliser D, Bode-Böger SM. ADMA increases arterial stiffness and decreases cerebral blood flow in humans. Stroke 2006; 37:2024-9. [PMID: 16809568 DOI: 10.1161/01.str.0000231640.32543.11] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND PURPOSE Preclinical studies have revealed that the endogenous nitric oxide synthase inhibitor, asymmetric dimethylarginine (ADMA), increases vascular tone in cerebral blood vessels. Marked elevations of ADMA blood levels were found in patients with diseases characterized by decreased cerebral perfusion, such as ischemic stroke. Arterial stiffness is an independent predictor of stroke and other adverse cardiovascular events. The aim of this study was to investigate the influence of a systemic subpressor dose of ADMA on arterial stiffness and cerebral perfusion in humans. METHODS Using a double-blind, vehicle-controlled study design, we allocated 20 healthy men in random order to infusion of either ADMA (0.10 mg ADMA/kg per min) or vehicle over a period of 40 minutes. Arterial stiffness was assessed noninvasively by pulse wave analysis. All volunteers underwent measurement of cerebral perfusion by dynamic contrast-enhanced perfusion magnetic resonance imaging of the brain. RESULTS Infusion of ADMA significantly decreased total cerebral perfusion by 15.1+/-4.5% (P=0.007), whereas blood flow in the vehicle group increased by 7.7+/-2.8% (P=0.02). ADMA also increased arterial stiffness as assessed by measurement of the augmentation index (-12.6+/-1.9 to -9.6+/-1.5, P=0.007). CONCLUSIONS Our results document for the first time that subpressor doses of ADMA increase vascular stiffness and decrease cerebral perfusion in healthy subjects. Thus, ADMA is an important endogenous modulator of cerebral vascular tone and may be involved in the pathogenesis of cerebrovascular disease.
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Affiliation(s)
- Jan T Kielstein
- Department of Nephrology, Medical School, Hannover, Germany.
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Knipp M. How to Control NO Production in Cells: Nω,Nω-Dimethyl-L-Arginine Dimethylaminohydrolase as a Novel Drug Target. Chembiochem 2006; 7:879-89. [PMID: 16680784 DOI: 10.1002/cbic.200500527] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Markus Knipp
- Department of Chemistry, University of Arizona, 1306 East University Boulevard, Tucson, AZ 85721-0041, USA.
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Abstract
There is abundant evidence that the endothelium plays a crucial role in the maintenance of vascular tone and structure. One of the major endothelium-derived vasoactive mediators is nitric oxide (NO), an endogenous messenger molecule formed in healthy vascular endothelium from the amino acid precursor L-arginine. Endothelial dysfunction is caused by various cardiovascular risk factors, metabolic diseases, and systemic or local inflammation. One mechanism that explains the occurrence of endothelial dysfunction is the presence of elevated blood levels of asymmetric dimethylarginine (ADMA)--an L-arginine analogue that inhibits NO formation and thereby can impair vascular function. Supplementation with L-arginine has been shown to restore vascular function and to improve the clinical symptoms of various diseases associated with vascular dysfunction.
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Affiliation(s)
- Rainer H Böger
- Clinical Pharmacology Unit, Institute of Experimental and Clinical Pharmacology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
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