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Forte A, Balistreri CR, De Feo M, Della Corte A, Hellstrand P, Persson L, Nilsson BO. Polyamines and microbiota in bicuspid and tricuspid aortic valve aortopathy. J Mol Cell Cardiol 2019; 129:179-187. [PMID: 30825483 DOI: 10.1016/j.yjmcc.2019.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 02/25/2019] [Indexed: 02/07/2023]
Abstract
Polyamines are small aliphatic cationic molecules synthesized via a highly regulated pathway and involved in general molecular and cellular phenomena. Both mammalian cells and microorganisms synthesize polyamines, and both sources may contribute to the presence of polyamines in the circulation. The dominant location for microorganisms within the body is the gut. Accordingly, the gut microbiota probably synthesizes most of the polyamines in the circulation in addition to those produced by the mammalian host cells. Polyamines are mandatory for cellular growth and proliferation. Established evidence suggests that the polyamine spermidine prolongs lifespan and improves cardiovascular health in animal models and humans through both local mechanisms, involving improved cardiomyocyte function, and systemic mechanisms, including increased NO bioavailability and reduced systemic inflammation. Higher levels of polyamines have been detected in non-dilated aorta of patients affected by bicuspid aortic valve congenital malformation, an aortopathy associated with an increased risk for thoracic ascending aorta aneurysm. In this review, we discuss metabolism of polyamines and their potential effects on vascular smooth muscle and endothelial cell function in vascular pathology of the thoracic ascending aorta associated with bicuspid or tricuspid aortic valve.
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Affiliation(s)
- Amalia Forte
- Department of Translational Medical Sciences, Università degli Studi della Campania "L. Vanvitelli", Naples, Italy
| | - Carmela Rita Balistreri
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, Palermo, Italy
| | - Marisa De Feo
- Department of Translational Medical Sciences, Università degli Studi della Campania "L. Vanvitelli", Naples, Italy
| | - Alessandro Della Corte
- Department of Translational Medical Sciences, Università degli Studi della Campania "L. Vanvitelli", Naples, Italy
| | - Per Hellstrand
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Lo Persson
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Bengt-Olof Nilsson
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
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Beneficial effects of spermidine on cardiovascular health and longevity suggest a cell type-specific import of polyamines by cardiomyocytes. Biochem Soc Trans 2018; 47:265-272. [PMID: 30578348 DOI: 10.1042/bst20180622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/16/2018] [Accepted: 11/21/2018] [Indexed: 01/04/2023]
Abstract
Recent and exciting in vivo studies show that supplementation with the polyamine spermidine (Spd) is cardioprotective and prolongs lifespan in both mice and humans. The mechanisms behind Spd-induced cardioprotection are supposed to involve Spd-evoked stimulation of autophagy, mitophagy and mitochondrial respiration and improved the mechano-elastical function of cardiomyocytes. Although cellular uptake of Spd was not characterized, these results suggest that Spd is imported by the cardiomyocytes and acts intracellularly. In the light of these new and thrilling data, we discuss in the present review cellular polyamine import with a special focus on mechanisms that may be relevant for Spd uptake by electrically excitable cells such as cardiomyocytes.
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Houen G. Mammalian Cu-containing amine oxidases (CAOs): New methods of analysis, structural relationships, and possible functions. APMIS 2017; 107:5-46. [DOI: 10.1111/apm.1999.107.s96.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Muth A, Madan M, Archer JJ, Ocampo N, Rodriguez L, Phanstiel O. Polyamine transport inhibitors: design, synthesis, and combination therapies with difluoromethylornithine. J Med Chem 2014; 57:348-63. [PMID: 24405276 DOI: 10.1021/jm401174a] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The development of polyamine transport inhibitors (PTIs), in combination with the polyamine biosynthesis inhibitor difluoromethylornithine (DFMO), provides a method to target cancers with high polyamine requirements. The DFMO+PTI combination therapy results in sustained intracellular polyamine depletion and cell death. A series of substituted benzene derivatives were evaluated for their ability to inhibit the import of spermidine in DFMO-treated Chinese hamster ovary (CHO) and L3.6pl human pancreatic cancer cells. Several design features were discovered which strongly influenced PTI potency, sensitivity to amine oxidases, and cytotoxicity. These included changes in (a) the number of polyamine chains appended to the ring system, (b) the polyamine sequence, (c) the attachment linkage of the polyamine to the aryl core, and (d) the presence of a terminal N-methyl group. Of the series tested, the optimal design was N(1),N(1'),N(1″)-(benzene-1,3,5-triyltris(methylene))tris(N(4)-(4-(methylamino)butyl)butane-1,4-diamine, 6b, which contained three N-methylhomospermidine motifs. This PTI exhibited decreased sensitivity to amine oxidases and low toxicity as well as high potency (EC50 = 1.4 μM) in inhibiting the uptake of spermidine (1 μM) in DFMO-treated L3.6pl human pancreatic cancer cells.
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Affiliation(s)
- Aaron Muth
- Department of Chemistry, University of Central Florida , 4000 Central Florida Boulevard, Orlando, Florida 32816-2366, United States
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Brooks BA, Heffernan S, Thomson S, McLennan SV, Twigg SM, Yue DK. The effects of diabetes and aminoguanidine treatment on endothelial function in a primate model of type 1 diabetes. Am J Primatol 2008; 70:796-802. [DOI: 10.1002/ajp.20550] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
Owing to their high turnover, the intestinal mucosal cells have a particularly high requirement for polyamines. Therefore, they are an excellent charcol for the study of polyamine function in rapid physiological growth and differentiation. After a cursory introduction to the major aspects of polyamine metabolism, regulation, and mode of action, we discuss the contribution of the polyamines to the maintenance of normal gut function, the maturation of the intestinal mucosa, and its repair after injuries. Repletion of cellular polyamine pools with (D,L)-2-(difluoromethyl)ornithine has considerably improved our understanding of how the polyamines are involved in the regulation of normal and neoplastic growth. Unfortunately, the attempts to exploit polyamine metabolism as a cancer therapeutic target have not yet been successful. However, the selective inactivation of ornithine decarboxylase appears to be a promising chemopreventive method in familial adenomatous polyposis. Presumably, it relies on the fact that ornithine decarboxylase is a critical regulator of the proliferative response of the protooncogene c-myc, but not of its apoptotic response.
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Affiliation(s)
- Nikolaus Seiler
- INSERM U682, Université Louis Pasteur EA3430, Faculty of Medicine, Laboratory of Nutritional Cancer Prevention, IRCAD, Strasbourg, France
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Mollace V, Muscoli C, Masini E, Cuzzocrea S, Salvemini D. Modulation of prostaglandin biosynthesis by nitric oxide and nitric oxide donors. Pharmacol Rev 2005; 57:217-52. [PMID: 15914468 DOI: 10.1124/pr.57.2.1] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biosynthesis and release of nitric oxide (NO) and prostaglandins (PGs) share a number of similarities. Two major forms of nitric-oxide synthase (NOS) and cyclooxygenase (COX) enzymes have been identified to date. Under normal circumstances, the constitutive isoforms of these enzymes (constitutive NOS and COX-1) are found in virtually all organs. Their presence accounts for the regulation of several important physiological effects (e.g. antiplatelet activity, vasodilation, and cytoprotection). On the other hand, in inflammatory setting, the inducible isoforms of these enzymes (inducible NOS and COX-2) are detected in a variety of cells, resulting in the production of large amounts of proinflammatory and cytotoxic NO and PGs. The release of NO and PGs by the inducible isoforms of NOS and COX has been associated with the pathological roles of these mediators in disease states as evidenced by the use of selective inhibitors. An important link between the NOS and COX pathways was made in 1993 by Salvemini and coworkers when they demonstrated that the enhanced release of PGs, which follows inflammatory mechanisms, was nearly entirely driven by NO. Such studies raised the possibility that COX enzymes represent important endogenous "receptor" targets for modulating the multifaceted roles of NO. Since then, numerous papers have been published extending the observation across various cellular systems and animal models of disease. Furthermore, other studies have highlighted the importance of such interaction in physiology as well as in the mechanism of action of drugs such as organic nitrates. More importantly, mechanistic studies of how NO switches on/off the PG/COX pathway have been undertaken and additional pathways through which NO modulates prostaglandin production unraveled. On the other hand, NO donors conjugated with COX inhibitors have recently found new interest in the understanding of NO/COX reciprocal interaction and potential clinical use. The purpose of this article is to cover the advances which have occurred over the years, and in particular, to summarize experimental data that outline how the discovery that NO modulates prostaglandin production has impacted and extended our understanding of these two systems in physiopathological events.
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Affiliation(s)
- Vincenzo Mollace
- Faculty of Pharmacy, University of Catanzaro Magna Graecia, Roccelletta di Borgia, Catanazaro, Italy
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Genovese T, Cuzzocrea S, Di Paola R, Failla M, Mazzon E, Sortino MA, Frasca G, Gili E, Crimi N, Caputi AP, Vancheri C. Inhibition or knock out of inducible nitric oxide synthase result in resistance to bleomycin-induced lung injury. Respir Res 2005; 6:58. [PMID: 15955252 PMCID: PMC1177992 DOI: 10.1186/1465-9921-6-58] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Accepted: 06/14/2005] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND In the present study, by comparing the responses in wild-type mice (WT) and mice lacking (KO) the inducible (or type 2) nitric oxide synthase (iNOS), we investigated the role played by iNOS in the development of on the lung injury caused by bleomycin administration. When compared to bleomycin-treated iNOSWT mice, iNOSKO mice, which had received bleomycin, exhibited a reduced degree of the (i) lost of body weight, (ii) mortality rate, (iii) infiltration of the lung with polymorphonuclear neutrophils (MPO activity), (iv) edema formation, (v) histological evidence of lung injury, (vi) lung collagen deposition and (vii) lung Transforming Growth Factor beta1 (TGF-beta1) expression. METHODS Mice subjected to intratracheal administration of bleomycin developed a significant lung injury. Immunohistochemical analysis for nitrotyrosine revealed a positive staining in lungs from bleomycin-treated iNOSWT mice. RESULTS The intensity and degree of nitrotyrosine staining was markedly reduced in tissue section from bleomycin-iNOSKO mice. Treatment of iNOSWT mice with of GW274150, a novel, potent and selective inhibitor of iNOS activity (5 mg/kg i.p.) also significantly attenuated all of the above indicators of lung damage and inflammation. CONCLUSION Taken together, our results clearly demonstrate that iNOS plays an important role in the lung injury induced by bleomycin in the mice.
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Affiliation(s)
- Tiziana Genovese
- Department of Clinical and Experimental Medicine and Pharmacology, Torre Biologica, Policlinico Universitario, 98123 Messina, Italy
| | - Salvatore Cuzzocrea
- Department of Clinical and Experimental Medicine and Pharmacology, Torre Biologica, Policlinico Universitario, 98123 Messina, Italy
| | - Rosanna Di Paola
- Department of Clinical and Experimental Medicine and Pharmacology, Torre Biologica, Policlinico Universitario, 98123 Messina, Italy
| | - Marco Failla
- Department of Internal and Specialistic Medicine, Section of Respiratory Diseases, University of Catania, Catania, Italy
| | - Emanuela Mazzon
- Department of Clinical and Experimental Medicine and Pharmacology, Torre Biologica, Policlinico Universitario, 98123 Messina, Italy
| | - Maria Angela Sortino
- Department of Experimental and Clinical Pharmacology, University of Catania, Catania, Italy
| | - Giuseppina Frasca
- Department of Experimental and Clinical Pharmacology, University of Catania, Catania, Italy
| | - Elisa Gili
- Department of Internal and Specialistic Medicine, Section of Respiratory Diseases, University of Catania, Catania, Italy
| | - Nunzio Crimi
- Department of Internal and Specialistic Medicine, Section of Respiratory Diseases, University of Catania, Catania, Italy
| | - Achille P Caputi
- Department of Clinical and Experimental Medicine and Pharmacology, Torre Biologica, Policlinico Universitario, 98123 Messina, Italy
| | - Carlo Vancheri
- Department of Internal and Specialistic Medicine, Section of Respiratory Diseases, University of Catania, Catania, Italy
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Brodal BP, Eliassen KA, Rönning H, Osmundsen H. Effects of dietary polyamines and clofibrate on metabolism of polyamines in the rat. J Nutr Biochem 2005; 10:700-8. [PMID: 15539269 DOI: 10.1016/s0955-2863(99)00058-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/1998] [Accepted: 08/04/1999] [Indexed: 11/21/2022]
Abstract
The activities of catalase, polyamine oxidase, diamine oxidase, ornithine decarboxylase, and peroxisomal beta-oxidation were assayed in homogenates from liver and small intestinal mucosa of rats which had been fed either a diet very low in polyamines or a diet containing five times the levels of dietary polyamines (putrescine, spermine, and spermidine) found in a standard rat diet. In rats fed the high polyamine diet, hepatic activities of catalase and polyamine oxidase were significantly decreased. Levels of the other activities were unchanged, except that intestinal ornithine decarboxylase was decreased. In rats treated simultaneously with clofibrate, the high polyamine diet restored activities of catalase, ornithine decarboxylase, and polyamine oxidase back to levels found in rats fed the low polyamine diet. The expected increase in activity of peroxisomal beta-oxidation was observed, although this was somewhat diminished in rats fed the high polyamine diet. Intestinal diamine oxidase activity was stimulated by clofibrate, particularly in rats fed the high polyamine diet. For the duration of the experiment (20 days), levels of putrescine, spermine, and spermidine in blood remained remarkably constant irrespective of treatment, suggesting that polyamine homeostasis is essentially independent of dietary supply of polyamines. It is suggested that intestinal absorption/metabolism of polyamines is of significance in this respect. Treatment with clofibrate appeared to alter polyamine homeostasis.
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Affiliation(s)
- B P Brodal
- Department of Oral Biology, University of Oslo, Oslo, Norway
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Wu B, Iwakiri R, Tsunada S, Utsumi H, Kojima M, Fujise T, Ootani A, Fujimoto K. iNOS enhances rat intestinal apoptosis after ischemia-reperfusion. Free Radic Biol Med 2002; 33:649-58. [PMID: 12208351 DOI: 10.1016/s0891-5849(02)00917-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The aim of this study was to demonstrate (i) the role of iNOS (inducible nitric oxide synthase) on apoptosis in the rat intestinal mucosa after ischemia-reperfusion, and (ii) the effect of iNOS on the release of cytochrome c from mitochondria. The superior mesenteric artery was occluded for 60 min and was followed by a 60 min reperfusion. Rats were pretreated with an intraperitoneal injection of the following iNOS inhibitors: N-nitro-L-arginine methyl ester, aminoguanidine, and (1S,5S,6R,7R)-7- chloro-3-imino-5-methyl-2-azabicyclo [4. 1. 0] heptane hydrochloride (ONO-1714). Apoptosis was evaluated and NO(X) in the portal vein was assayed. The amount of iNOS, caspase-3, and cytochrome c were determined by a Western blot analysis. Intestinal mucosal epithelial mitochondrial dehydrogenase activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoilium bromide. Ischemia-reperfusion increased intestinal mucosal apoptosis, NO(X) production in the portal vein, the amount of iNOS protein, and the release of cytochrome c, but not caspase-3. Inhibitors of iNOS significantly attenuated the induction of apoptosis, increased NO(X) production, and release of cytochrome c. Mitochondrial dysfunction was induced by ischemia-reperfusion, which was ameliorated by iNOS inhibitors. Our results indicate that iNOS is related to increased mucosal apoptosis in the rat small intestine after ischemia-reperfusion, which is partly explained by the release of cytochrome c from mitochondria to cytosols following mitochondrial dysfunction.
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Affiliation(s)
- Bin Wu
- Department of Internal Medicine, Saga Medical School, Nabeshima, Saga, Japan
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Kitanaka J, Kitanaka N, Tsujimura T, Terada N, Takemura M. Expression of diamine oxidase (histaminase) in guinea-pig tissues. Eur J Pharmacol 2002; 437:179-85. [PMID: 11890907 DOI: 10.1016/s0014-2999(02)01302-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The expression of mRNA for diamine oxidase (histaminase) and the enzyme activity in guinea-pig tissues were investigated. Reverse transcription-polymerase chain reaction analysis revealed that the message corresponding to the long form present in humans and rats was expressed abundantly in the small intestine and liver. Small but detectable amounts of diamine oxidase mRNA were observed in the kidney, stomach, cerebellum, thalamus+hypothalamus, and cerebral cortex. Northern blot analysis showed that the message (2.8 kb in size) was observed abundantly in the liver and small intestine and was detectable in the kidney and stomach but not in the brain or lung. In situ hybridization showed that diamine oxidase mRNA was localized throughout the liver and epithelial cells of the small intestine. Diamine oxidase activity was detected at various levels in different tissues of the guinea-pig at the following relative abundance: liver>small intestine>lung, kidney>stomach. Histamine dose-dependently induced the contraction of sections of the guinea-pig small intestine, and the pretreatment of the tissue section with aminoguanidine (100 microM), a diamine oxidase inhibitor, but not with S-[4-(N,N-dimethylamino)butyl]isothiourea (100 microM), an inhibitor of histamine N-methyltransferase, shifted the dose-response curve of histamine-induced contraction to lower concentrations. These results suggest that diamine oxidase has a crucial role in the degradation of histamine in the guinea-pig small intestine and probably in the liver.
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Affiliation(s)
- Junichi Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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Abstract
This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated.
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Abstract
This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated.
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Alderton WK, Cooper CE, Knowles RG. Nitric oxide synthases: structure, function and inhibition. Biochem J 2001; 357:593-615. [PMID: 11463332 PMCID: PMC1221991 DOI: 10.1042/0264-6021:3570593] [Citation(s) in RCA: 1583] [Impact Index Per Article: 68.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated.
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Affiliation(s)
- W K Alderton
- In Vitro Pharmacology Department, GlaxoSmithKline Research and Development, Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, UK
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