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Lo A, Norcliffe-Kaufmann L, Vickery R, Bourdet D, Kanodia J. Pharmacokinetics and pharmacodynamics of ampreloxetine, a novel, selective norepinephrine reuptake inhibitor, in symptomatic neurogenic orthostatic hypotension. Clin Auton Res 2021; 31:395-403. [PMID: 33782836 PMCID: PMC8184714 DOI: 10.1007/s10286-021-00800-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/19/2021] [Indexed: 12/23/2022]
Abstract
Purpose Ampreloxetine is a novel, selective, long-acting norepinephrine reuptake (NET) inhibitor being investigated as a once-daily oral treatment for symptomatic neurogenic orthostatic hypotension (nOH) in patients with autonomic synucleinopathies. The purpose of this study was to characterize the pharmacokinetic and pharmacodynamic profiles of ampreloxetine in this target population. Methods Patients with nOH were enrolled in a multicenter, phase II clinical trial of ampreloxetine (NCT02705755). They received escalating doses over 5 days in the clinical research unit, followed by 20 weeks of open-label treatment and then a 4-week withdrawal. As neurochemical biomarkers of NET inhibition, we assayed plasma concentrations of norepinephrine (NE) and its main intraneuronal metabolite 3,4-dihydroxyphenylglycol (DHPG) pre- and post-ampreloxetine. Results Thirty-four patients with nOH were enrolled. Plasma ampreloxetine concentrations increased with repeated escalating doses, with peak concentrations observed 6–9 h post-drug administration. The median ampreloxetine dose in the 20-week treatment phase was 10 mg once daily. Plasma ampreloxetine concentrations reached steady state by 2 weeks, with stable plasma levels over 24 h. No influence of age or renal function on ampreloxetine plasma concentrations was observed. On treatment, compared to baseline, plasma NE significantly increased by 71% (p < 0.005), plasma DHPG significantly declined by 22% (p < 0.05), and the NE:DHPG ratio significantly increased (p < 0.001). Conclusions Persistent elevation of plasma NE levels accompanied by reduced DHPG levels after ampreloxetine suggests reduced neuronal reuptake and metabolism of NE in postganglionic efferent sympathetic neurons. The findings are consistent with long-lasting NET inhibition, which may increase vasoconstrictor tone, supporting once-daily ampreloxetine dosing in patients with nOH.
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Affiliation(s)
- Arthur Lo
- Clinical and Translational Pharmacology, Theravance Biopharma US, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA
| | - Lucy Norcliffe-Kaufmann
- Clinical and Translational Pharmacology, Theravance Biopharma US, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA.,Clinical Science, Neurology, Theravance Biopharma US, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA
| | - Ross Vickery
- Theravance Biopharma Ireland Limited, Dublin, Ireland
| | - David Bourdet
- Clinical and Translational Pharmacology, Theravance Biopharma US, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA
| | - Jitendra Kanodia
- Clinical and Translational Pharmacology, Theravance Biopharma US, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA.
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An Y, Reimann M, Masjkur J, Langton K, Peitzsch M, Deutschbein T, Fassnacht M, Rogowski-Lehmann N, Beuschlein F, Fliedner S, Stell A, Prejbisz A, Januszewicz A, Lenders J, Bornstein SR, Eisenhofer G. Adrenomedullary function, obesity and permissive influences of catecholamines on body mass in patients with chromaffin cell tumours. Int J Obes (Lond) 2018; 43:263-275. [PMID: 29717268 DOI: 10.1038/s41366-018-0054-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/10/2018] [Accepted: 01/31/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND Obesity-associated activation of sympathetic nervous outflow is well documented, whereas involvement of dysregulated adrenomedullary hormonal function in obesity is less clear. This study assessed relationships of sympathoadrenal function with indices of obesity and influences of circulating catecholamines on body mass. METHODS Anthropometric and clinical data along with plasma and 24-h urine samples were collected from 590 volunteers and 1368 patients tested for phaeochromocytoma and paraganglioma (PPGL), among whom tumours were diagnosed in 210 individuals. RESULTS Among patients tested for PPGL, those with tumours less often had a body mass index (BMI) above 30 kg/m2 (12 vs. 31%) and more often a BMI under 25 kg/m2 (56 vs. 32%) than those without tumours (P < 0.0001). Urinary outputs of catecholamines in patients with PPGL were negatively related to BMI (r = -0.175, P = 0.0133). Post-operative weight gain (P < 0.0001) after resection of PPGL was positively related to presurgical tumoural catecholamine output (r = 0.257, P = 0.0101). Higher BMI in men and women and percent body fat in women of the volunteer group were associated with lower plasma concentrations and urinary outputs of adrenaline and metanephrine, the former indicating obesity-related reduced adrenaline secretion and the latter obesity-related reduced adrenomedullary adrenaline stores. Daytime activity was associated with substantial increases in urinary adrenaline and noradrenaline excretion, with blunted responses in obese subjects. CONCLUSIONS The findings in patients with PPGL support an influence of high circulating catecholamines on body weight. Additional associations of adrenomedullary dysfunction with obesity raise the possibility of a permissive influence of the adrenal medulla on the regulation of body weight.
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Affiliation(s)
- Yaxin An
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Manja Reimann
- Department of Neurology, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Jimmy Masjkur
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Katharina Langton
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Mirko Peitzsch
- Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Timo Deutschbein
- Department of Internal Medicine, Division of Endocrinology, University Hospital, University of Würzburg, Würzburg, Germany
| | - Martin Fassnacht
- Department of Internal Medicine, Division of Endocrinology, University Hospital, University of Würzburg, Würzburg, Germany
| | - Natalie Rogowski-Lehmann
- Medizinische Klinik und Poliklinik IV, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany
| | - Felix Beuschlein
- Medizinische Klinik und Poliklinik IV, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany.,Department of Endocrinology, Diabetology and Clinical Nutrition, UnviersitätsSpital Zürich, Zurich, Switzerland
| | - Stephanie Fliedner
- Department of Medicine, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Anthony Stell
- Department of Computing and Information, University of Melbourne, Melbourne, Australia
| | | | | | - Jacques Lenders
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Department of Internal Medicine, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Stefan R Bornstein
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Graeme Eisenhofer
- Department of Medicine III, Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. .,Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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Structural Remodeling of Sympathetic Innervation in Atherosclerotic Blood Vessels: Role of Atherosclerotic Disease Progression and Chronic Social Stress. Psychosom Med 2017; 79:59-70. [PMID: 27359178 PMCID: PMC5182089 DOI: 10.1097/psy.0000000000000360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The sympathetic nervous system (SNS) can undergo dramatic structural plasticity in response to behavioral factors and/or the presence of disease, leading to SNS hyperinnervation of peripheral tissues. The SNS has been proposed as an important mediator between stressful behavior and the progression of atherosclerosis in the vasculature. The present study examined whether structural remodeling of the SNS occurs in the vasculature in a genetically hyperlipidemic animal model of atherosclerosis, the Watanabe heritable hyperlipidemic rabbit (WHHL; relative to normolipidemic New Zealand white rabbits [NZW]), and whether SNS plasticity is driven by the progression of disease and/or by stressful social behavior. METHODS WHHL and NZW rabbits were assigned to an unstable or stable social environment for 4 months. Aortic atherosclerosis was assessed and SNS aortic innervation quantified using immunofluorescent microscopy. RESULTS Numerous SNS varicosities were observed throughout the aorta in WHHLs and NZWs, extending into the vascular media and intima, an innervation pattern not previously reported. WHHLs exhibited significantly greater innervation than NZWs (F(1,41) = 55.3, p < .001), with extensive innervation of the atherosclerotic neointima. The innervation density was highly correlated with the extent of disease in the WHHLs (r(21) = 0.855, p < .001). Social environment did not influence innervation in NZWs (aortic arch: p = .078, thoracic aorta: p = .34) or WHHLs (arch: p = .97, thoracic: p = .61). CONCLUSIONS The findings suggest that hyperinnervation is driven largely by the progression of disease rather than social environment. SNS innervation patterns observed in atherosclerotic human and mouse aortas were consistent with the rabbit, suggesting that SNS hyperinnervation of the diseased vessel wall is a general feature across mammalian species.
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The timing of dopamine- and noradrenaline-mediated transmission reflects underlying differences in the extent of spillover and pooling. J Neurosci 2014; 34:7645-56. [PMID: 24872568 DOI: 10.1523/jneurosci.0166-14.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabotropic transmission typically occurs through the spillover activation of extrasynaptic receptors. This study examined the mechanisms underlying somatodendritic dopamine and noradrenaline transmission and found that the extent of spillover and pooling varied dramatically between these two transmitters. In the mouse ventral tegmental area, the time course of D2-receptor-mediated IPSCs (D2-IPSCs) was consistent between cells and was unaffected by altering stimulation intensity, probability of release, or the extent of diffusion. Blocking dopamine reuptake with cocaine extended the time course of D2-IPSCs and suggested that transporters strongly limited spillover. As a result, individual release sites contributed independently to the duration of D2-IPSCs. In contrast, increasing the release of noradrenaline in the rat locus ceruleus prolonged the duration of α2-receptor-mediated IPSCs even when reuptake was intact. Spillover and subsequent pooling of noradrenaline activated distal α2-receptors, which prolonged the duration of α2-IPSCs when multiple release sites were activated synchronously. By using the rapid application of agonists onto large macropatches, we determined the concentration profile of agonists underlying the two IPSCs. Incorporating the results into a model simulating extracellular diffusion predicted that the functional range of noradrenaline diffusion was nearly fivefold greater in the locus ceruleus than dopamine in the midbrain. This study demonstrates that catecholamine synapses differentially regulate the extent of spillover and pooling to control the timing of local inhibition and suggests diversity in the roles of uptake and diffusion in governing metabotropic transmission.
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Meyer-Hermann M, Figge MT, Straub RH. Mathematical modeling of the circadian rhythm of key neuroendocrine-immune system players in rheumatoid arthritis: a systems biology approach. ACTA ACUST UNITED AC 2009; 60:2585-94. [PMID: 19714618 DOI: 10.1002/art.24797] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Healthy subjects and patients with rheumatoid arthritis (RA) exhibit circadian rhythms of the neuroendocrine-immune system. Understanding circadian dynamics is complex due to the nonlinear behavior of the neuroendocrine-immune network. This study was undertaken to seek and test a mathematical model for studying this network. METHODS We established a quantitative computational model to simulate nonlinear interactions between key factors in the neuroendocrine-immune system, such as plasma tumor necrosis factor (TNF), plasma cortisol (and adrenal cholesterol store), and plasma noradrenaline (NA) (and presynaptic NA store). RESULTS The model was nicely fitted with measured reference data on healthy subjects and RA patients. Although the individual circadian pacemakers of cortisol, NA, and TNF were installed without a phase shift, the relative phase shift between these factors evolved as a consequence of the modeled network interactions. Combined long-term and short-term TNF increase (the "RA model") increased cortisol plasma levels for only a few days, and cholesterol stores started to become markedly depleted. This nicely demonstrated the phenomenon of inadequate cortisol secretion relative to plasma TNF levels, as a consequence of adrenal deficiency. Using the RA model, treatment with glucocorticoids between midnight and 2:00 AM was found to have the strongest inhibitory effect on TNF secretion, which supports recent studies on RA therapy. Long-term reduction of TNF levels by simulation of anti-TNF therapy normalized cholesterol stores under "RA" conditions. CONCLUSION These first in silico studies of the neuroendocrine-immune system in rheumatology demonstrate that computational biology in medicine, making use of large collections of experimental data, supports understanding of the pathophysiology of complex nonlinear systems.
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Affiliation(s)
- Michael Meyer-Hermann
- Systems Immunology, Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, Frankfurt/Main, Germany.
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De Luca G, Glavinović MI. Glutamate, water and ion transport through a charged nanosize pore. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:264-79. [PMID: 17014822 DOI: 10.1016/j.bbamem.2006.08.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 08/07/2006] [Accepted: 08/15/2006] [Indexed: 11/18/2022]
Abstract
The transport of transmitter, ions and water through a positively-charged nanopore was investigated through computer simulations. The physics of the problem is described by a coupled set of Poisson-Nernst-Planck and Navier-Stokes equations in a computational domain consisting a cylindrical pore, whose radius ranged from 1 to 8 nm and which was flanked by two compartments representing the vesicular interior and extra-cellular space. The concentration of co-ions is suppressed and of counter-ions enhanced, especially near the pore wall owing to electrostatic interactions. Glutamate (i.e. the transmitter considered) is negatively charged and is simulated as a counter-ion. The electro-kinetically induced pressure due to the movement of ions is negative and very pronounced near the pore wall where the concentration and flux of counter-ions is very high. The water velocity peaks in the pore center, diminishes to zero at the pore wall, but is constant along the pore axis. The mean velocity of the water/fluid is proportional to the vesicular pressure and pore cross-sectional area. Interestingly it is inversely related to the vesicular glutamate concentration. The factors determining the glutamate flux are complex. The diffusive flux generally predominates for narrow pore, and convective flux may dominate for wide pore if the vesicular pressure is high. Surprisingly at low vesicular pressure the mean total glutamate flux per unit cross-sectional pore area is higher for narrow pores. Higher flux is probably due to the rise of glutamate concentration in the nanopore, which is much more pronounced for narrow nanopores, due to the maintenance of approximate neutrality of charges in the pore and on the pore wall. In conclusion intra-vesicular pressure helps 'flushing-out' the transmitter, but the induced pressure 'drags-out' the water into the extra-cellular space.
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Affiliation(s)
- G De Luca
- Department of Chemical Engineering, McGill University, Montreal, PQ, Canada
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Bennett MR, Farnell L, Gibson WG. A quantitative description of the contraction of blood vessels following the release of noradrenaline from sympathetic varicosities. J Theor Biol 2005; 234:107-22. [PMID: 15721040 DOI: 10.1016/j.jtbi.2004.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 10/23/2004] [Accepted: 11/11/2004] [Indexed: 11/24/2022]
Abstract
A model is presented that highlights the principal factors determining the form and extent of contraction in arteries upon stimulation of their sympathetic nerve supply. This model incorporates a previous quantitative model of the process of noradrenaline (NAd) diffusion into the vascular media and reuptake into sympathetic varicosities during nerve stimulation (J. Theor. Biol. 226 (2004) 359). It is also dependent on a model of how the subsequent activation of metabotropic receptors initiates a G-protein cascade, resulting in the production of inositol trisphosphate (IP3) and an increase in intracellular calcium concentration, [Ca2+]i, in the smooth muscle cells (J. Theor. Biol. 223 (2003) 93). In the present work we couple this rise in [Ca2+]i to the increase in phosphorylated myosin bound to actin in the cells and hence determine the force development in arteries due to nerve stimulation. The model accounts for force development as a function of [Ca2+]i and for the rate of change of force as a function of the rate of change of [Ca2+]i in single smooth muscle cells. It also accounts for the characteristic time course of the force developed by the media of the rat-tail artery upon nerve stimulation. This consists of a rapid rise to a transient peak followed by a sustained plateau of contraction during the stimulation period, after which the contraction slowly decays back to baseline at a rate dependent on the strength of the stimulation. The model indicates that the transient peak is primarily due to the partial block of the IP3 receptor by the rise in [Ca2+]i and that the main determinant of the equilibrium condition indicated by the plateau phase is the rate of pumping of calcium into the sarcoplasmic reticulum. The relatively slow decline of contraction at the end of nerve stimulation is primarily a consequence of the slow rates of removal of NAd from the media by diffusion and reuptake into the sympathetic varicosities. The model thus provides a quantitative account of vascular smooth muscle contraction upon sympathetic nerve stimulation.
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Affiliation(s)
- M R Bennett
- The Neurobiology Laboratory, Department of Physiology, and Institute for Biomedical Research, University of Sydney, NSW, 2006, Australia.
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