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Kranz M, Sattler B, Wüst N, Deuther-Conrad W, Patt M, Meyer PM, Fischer S, Donat CK, Wünsch B, Hesse S, Steinbach J, Brust P, Sabri O. Evaluation of the Enantiomer Specific Biokinetics and Radiation Doses of [(18)F]Fluspidine-A New Tracer in Clinical Translation for Imaging of σ₁ Receptors. Molecules 2016; 21:E1164. [PMID: 27598110 PMCID: PMC6273209 DOI: 10.3390/molecules21091164] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 11/17/2022] Open
Abstract
The enantiomers of [(18)F]fluspidine, recently developed for imaging of σ₁ receptors, possess distinct pharmacokinetics facilitating their use in different clinical settings. To support their translational potential, we estimated the human radiation dose of (S)-(-)-[(18)F]fluspidine and (R)-(+)-[(18)F]fluspidine from ex vivo biodistribution and PET/MRI data in mice after extrapolation to the human scale. In addition, we validated the preclinical results by performing a first-in-human PET/CT study using (S)-(-)-[(18)F]fluspidine. Based on the respective time-activity curves, we calculated using OLINDA the particular organ doses (ODs) and effective doses (EDs). The ED values of (S)-(-)-[(18)F]fluspidine and (R)-(+)-[(18)F]fluspidine differed significantly with image-derived values obtained in mice with 12.9 μSv/MBq and 14.0 μSv/MBq (p < 0.025), respectively. A comparable ratio was estimated from the biodistribution data. In the human study, the ED of (S)-(-)-[(18)F]fluspidine was calculated as 21.0 μSv/MBq. Altogether, the ED values for both [(18)F]fluspidine enantiomers determined from the preclinical studies are comparable with other (18)F-labeled PET imaging agents. In addition, the first-in-human study confirmed that the radiation risk of (S)-(-)-[(18)F]fluspidine imaging is within acceptable limits. However, as already shown for other PET tracers, the actual ED of (S)-(-)-[(18)F]fluspidine in humans was underestimated by preclinical imaging which needs to be considered in other first-in-human studies.
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Affiliation(s)
- Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Bernhard Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Nathanael Wüst
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Marianne Patt
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Philipp M Meyer
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
- Division of Brain Sciences, Department of Medicine, Hammersmith Hospital Campus, Imperial College London, London SW7 2AZ, UK.
| | - Bernhard Wünsch
- Pharmaceutical and Medicinal Chemistry, University Münster, Münster 48149, Germany.
| | - Swen Hesse
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
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Miyake Y, Wang X, Amasaka M, Itto K, Xu S, Arimoto H, Fujii H, Hirata H. Simultaneous Imaging of an Enantiomer Pair by Electron Paramagnetic Resonance Using Isotopic Nitrogen Labeling. Anal Chem 2012; 85:985-90. [DOI: 10.1021/ac302710m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yusuke Miyake
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Xiaolei Wang
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Mitsuo Amasaka
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Kaori Itto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Shu Xu
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirokazu Arimoto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirotada Fujii
- Department
of Arts and Sciences, Center for Medical Education, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo
060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
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PET kinetics of radiolabeled antidepressant, [N-methyl-11C]mirtazapine, in the human brain. EJNMMI Res 2011; 1:36. [PMID: 22214419 PMCID: PMC3261093 DOI: 10.1186/2191-219x-1-36] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 12/15/2011] [Indexed: 11/10/2022] Open
Abstract
Background We compared six kinetic models with and without the requirement of arterial cannulation for estimating the binding potential of [N-methyl-11C]mirtazapine in the living human brain. Methods Distribution volumes of [N-methyl-11C]mirtazapine in brain regions were estimated using single- and two-tissue compartment models as well as a graphical plasma input model. The two-tissue compartment model provided a direct estimate of the binding potentials of [N-methyl-11C]mirtazapine in brain regions, while binding potentials of the single-tissue compartment model and the graphical plasma input model were estimated indirectly from ratios of distribution volumes in brain regions. We obtained also direct estimates of binding potentials using a graphical reference tissue model and two nonlinear reference tissue models. Results The two-tissue compartment model required several fits with different initial guesses for avoiding negative values of parameters. Despite the extra fits, estimates of distribution volumes and binding potentials of [N-methyl-11C]mirtazapine obtained by the two-tissue compartment model were far more variable than those produced by the other methods. The graphical plasma input method and the graphical reference tissue method provided estimates of the binding potential that correlated closely, but differed in magnitude. The single-tissue compartment model provided relatively low estimates of binding potentials with curves that failed to fit the data as well as the three other methods that used the entire series of positron emission tomography data. The reference tissue method and the simplified reference tissue method provided similar, consistent estimates of binding potentials. However, certain assumptions of the simplified reference tissue method may not be fulfilled by the radioligand. Conclusion The reference tissue method is appropriate for estimating the binding potential of [N-methyl-11C]mirtazapine in regions of the human brain so that the binding potential of [N-methyl-11C]mirtazapine can be estimated without arterial cannulation.
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Guidi S, Bianchi P, Alstrup AKO, Henningsen K, Smith DF, Bartesaghi R. Postnatal neurogenesis in the hippocampal dentate gyrus and subventricular zone of the Göttingen minipig. Brain Res Bull 2011; 85:169-79. [PMID: 21501667 DOI: 10.1016/j.brainresbull.2011.03.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/24/2011] [Accepted: 03/31/2011] [Indexed: 01/18/2023]
Abstract
Postnatal neurogenesis is currently viewed as important for neuroplasticity and brain repair. We are, therefore, interested in animal models for neuroimaging of postnatal neurogenesis. A recent stereological study found an age-dependent increase in the number of neurons and glial cells in the neocortex of Göttingen minipigs, suggesting that this species may be characterized by a prolonged postnatal neurogenesis. Since there is no direct evidence on this issue, the goal of our study was to quantify cell proliferation in the two major neurogenic regions of the postnatal brain - the subventricular zone of the lateral ventricle (SVZ) and the hippocampal dentate gyrus (DG) - at two separate points during the lifespan of the minipig. Göttingen minipigs aged 6-7 and 32 weeks were injected with bromodeoxyuridine (BrdU), a marker of cycling cells, and killed after 2h. We found BrdU-positive cells numbering 165,000 in the SVZ and 35,000 in the DG at 6-7 weeks and 66,000 in the SVZ and 19,000 in the DG at 32 weeks-of-age. Stereology showed a 60% increase in the total number of DG granule cells between 6-7 and 32 weeks-of-age. Our findings show a continued postnatal neurogenesis in the major neurogenic regions of Göttingen minipigs, thereby providing a potential animal model for studies aimed at examining ongoing neurogenesis in the living brain with molecular neuroimaging technology.
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Affiliation(s)
- Sandra Guidi
- Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Piazza di Porta San Donato 2, I-40126 Bologna, Italy
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Lind AB, Reis M, Bengtsson F, Jonzier-Perey M, Powell Golay K, Ahlner J, Baumann P, Dahl ML. Steady-state concentrations of mirtazapine, N-desmethylmirtazapine, 8-hydroxymirtazapine and their enantiomers in relation to cytochrome P450 2D6 genotype, age and smoking behaviour. Clin Pharmacokinet 2009; 48:63-70. [PMID: 19071885 DOI: 10.2165/0003088-200948010-00005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND AND OBJECTIVE Mirtazapine is a tetracyclic antidepressant drug available as a racemic mixture of S(+)- and R(-)-mirtazapine. These enantiomers have different pharmacological properties, and both contribute to the clinical and adverse effects of the drug. Cytochrome P450 (CYP) 2D6 has been implicated in the metabolism of S(+)-mirtazapine. However, the effect of CYP2D6 on serum concentrations of the enantiomers of mirtazapine and its metabolites has not been assessed in patients on long-term treatment. The main objective of the study was to evaluate the effect of the CYP2D6 genotype on enantiomeric steady-state trough serum concentrations of mirtazapine and its metabolites N-desmethylmirtazapine and 8-hydroxymirtazapine. The effects of sex, age and smoking behaviour were also assessed. SUBJECTS AND METHODS The study included 95 patients who had depression according to the Diagnostic and Statistical Manual of Mental Disorders-4th Edition and were treated for 4 weeks with a daily dose of mirtazapine 30 mg. The serum concentrations of the enantiomers of mirtazapine and its metabolites were analysed by liquid chromatography-mass spectrometry, and the subjects were genotyped for CYP2D6 alleles *3, *4, *5 and *6 and gene duplication. RESULTS Three subjects (3%) were classified as ultrarapid metabolizers (UMs), 56 (59%) as homozygous extensive metabolizers (EMs), 30 (32%) as heterozygous EMs and 6 (6%) as poor metabolizers (PMs) of CYP2D6. The median trough serum concentrations of S(+)-mirtazapine were higher in PMs (59 nmol/L, p = 0.016) and in heterozygous EMs (39 nmol/L, p = 0.013) than in homozygous EMs (28 nmol/L). PMs and heterozygous EMs also had higher mirtazapine S(+)/R(-) ratios (0.4) than homozygous EMs (0.3, p = 0.015 and 0.004, respectively). The S(+)-N-desmethylmirtazapine concentration was higher in PMs (16 nmol/L) than in homozygous EMs (7 nmol/L, p = 0.043). There was an association between the CYP2D6 genotype and the ratio between S(+)-8-hydroxymirtazapine and S(+)-mirtazapine, with a significantly higher ratio in homozygous EMs than in heterozygous EMs (0.11 vs 0.05, p = 0.007). The influence of the CYP2D6 genotype on S(+)-mirtazapine, the mirtazapine S(+)/R(-) ratio and S(+)-N-desmethylmirtazapine remained significant after correction for the influence of sex, age and smoking. Smokers had significantly lower concentrations of S(+)-mirtazapine (23 vs 39 nmol/L, p = 0.026) and R(-)-N-desmethylmirtazapine (39 vs 51 nmol/L, p = 0.036) and a significantly lower mirtazapine S(+)/R(-) ratio (0.28 vs. 0.37, p = 0.014) than nonsmokers, and the effect of smoking remained significant after multivariate analysis. CONCLUSIONS This study is the first to show the impact of the CYP2D6 genotype on steady-state serum concentrations of the enantiomers of mirtazapine and its metabolites. Our results also support the role of CYP1A2 in the metabolism of mirtazapine, with lower serum concentrations in smokers than in nonsmokers.
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Affiliation(s)
- Anna-Britta Lind
- Department of Medical Sciences, Clinical Pharmacology, Uppsala University, Uppsala, Sweden
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Muth-Selbach U, Hermanns H, Driehsen C, Lipfert P, Freynhagen R. Racemic intrathecal mirtazapine but not its enantiomers acts anti-neuropathic after chronic constriction injury in rats. Brain Res Bull 2009; 79:63-8. [PMID: 19162140 DOI: 10.1016/j.brainresbull.2008.12.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 12/19/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
The unique noradrenergic and specific serotonergic antidepressant mirtazapine acts antinociceptive. It is optically active and currently marketed as racemate. In an animal model of acute pain it has been shown that the enantiomers exhibit differential effects: the R(-)-enantiomer showed anti-, the S(+)-enantiomer pronociceptive properties while the racemate acted antinociceptive at low doses and profoundly pronociceptive after high-dose application. Aim of the present study was to evaluate potential enantioselective effects of mirtazapine in neuropathic pain. In a chronic constriction injury model of neuropathic pain, Wistar rats were injected (+/-)-mirtazapine and the enantiomers intrathecally. All substances were dosed between 0.001 and 1mg/kg and compared to vehicle in a randomized and blinded approach. Thermal hyperalgesia and mechanical allodynia were assessed. In contrast to the acute pain results, only racemic mirtazapine exerted significant sustained analgesic effects up to 48 h. Antinociception was observed at all dosages with a maximum in the range of 0.01 mg/kg. Surprisingly, neither enantiomer was pro- nor antinociceptive at any dose or time. Our findings suggest that the synergism of both enantiomers is required to evoke a significant analgesic effect for the treatment of neuropathic pain. Our study gained no evidence for the use of either R(-) nor S(+)-mirtazapine alone. Due to the unique characteristics of (+/-)-mirtazapine and its proven efficacy in acute pain our results suggest that racemic mirtazapine may be a particularly useful antidepressant in the adjunctive treatment of chronic neuropathic pain states and could provide additional benefit to current therapeutic options.
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Affiliation(s)
- Uta Muth-Selbach
- Klinik für Anästhesiologie, Universitätsklinikum Düsseldorf, Moorenstr. 5, Postfach 101007, 40225 Düsseldorf, Germany.
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Smith DF, Hansen SB, Jakobsen S, Bender D, Audrain H, Ashkanian M, Stork BS, Minuzzi L, Hall H, Rosenberg R. Neuroimaging of mirtazapine enantiomers in humans. Psychopharmacology (Berl) 2008; 200:273-9. [PMID: 18566802 DOI: 10.1007/s00213-008-1208-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 05/12/2008] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Mirtazapine is a racemic antidepressant with a multireceptor profile. Previous studies have shown that the enantiomers of mirtazapine have different pharmacologic effects in the brain of laboratory animals. MATERIALS AND METHODS In the present study, we used positron emission tomography (PET) and autoradiography to study effects of (R)- and (S)-[(11)C]mirtazapine in the human brain. Detailed brain imaging by PET using three methods of kinetic data analysis showed no reliable differences between regional binding potentials of (R)- and (S)-[(11)C]mirtazapine in healthy subjects. RESULTS Autoradiographic studies carried out in whole hemispheres of human brain tissue showed, however, that (R)- and (S)-mirtazapine differ markedly as inhibitors of [(3)H]clonidine binding at alpha(2)-adrenoceptors. CONCLUSION The multireceptor binding profiles of mirtazapine enantiomers, along with individual differences between subjects, may preclude PET neuroimaging from demonstrating reliable differences between the regional distribution and binding of (R)- and (S)-[(11)C]mirtazapine in the living human brain.
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Affiliation(s)
- Donald F Smith
- Center for Psychiatric Research, Psychiatric Hospital of Aarhus University, 8240, Risskov, Denmark.
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Hong X, Yao Y, Hong S, Lei C. LC–MS–MS Analysis of Mirtazapine in Plasma, and Determination of Pharmacokinetic Data for Rats. Chromatographia 2008. [DOI: 10.1365/s10337-008-0656-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Smith DF, Jakobsen S. Stereoselective neuroimaging in vivo. Eur Neuropsychopharmacol 2007; 17:507-22. [PMID: 17368004 DOI: 10.1016/j.euroneuro.2007.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Revised: 01/17/2007] [Accepted: 02/06/2007] [Indexed: 01/08/2023]
Abstract
Stereoselectivity is a basic property of many neuronal processes due to the spatial features of molecules involved in neurotransmission. Today, neuroimaging procedures are available for studying stereoselectivity in the living brain. Mirror-image radiotracers are the molecular tools that are used, together with single photon emission tomography (SPECT) and positron emission tomography (PET), for studying stereoselective neuronal mechanisms. This review presents the findings obtained in those studies of cholinergic, noradrenergic, dopaminergic, serotonergic, glutamatergic, opioid, cannabinoid, and second messenger neurotransmission.
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Affiliation(s)
- Donald F Smith
- Center for Psychiatric Research, Psychiatric Hospital of Aarhus University, 8240 Risskov, Denmark.
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Brockmöller J, Meineke I, Kirchheiner J. Pharmacokinetics of mirtazapine: enantioselective effects of the CYP2D6 ultra rapid metabolizer genotype and correlation with adverse effects. Clin Pharmacol Ther 2007; 81:699-707. [PMID: 17329996 DOI: 10.1038/sj.clpt.6100116] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Enantiomerically pure drugs and genotyping are promising approaches to achieve optimization in antidepressant therapy. Mirtazapine is a mixed noradrenergic serotoninergic antidepressant used as a racemate. We analyzed pharmacokinetics of its enantiomers in relation to CYP2D6 genotype and in relation to its adverse effects. Mirtazapine was enantioselectively absorbed from the gut with a rate constant of 0.2 min-1 for S+, but 0.08 min-1 for R- mirtazapine. Kinetics of R- mirtazapine was only marginally dependent on CYP2D6 genotype, but total clearance of the S+ enantiomer were 1.3, 2.3, and 3.4 L min-1 in poor, extensive, and ultrarapid metabolizers of CYP2D6 substrates with apparent substantial first-pass metabolism in rapid and ultrarapid metabolizers. Mirtazapine effects on heart rate and blood pressure correlated much more strongly with R- then with S+ concentrations, whereas sedation correlated similarly with both enantiomers. At least concerning some adverse effects, it might be worthwhile to study further mirtazapine enantiospecifically.
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Affiliation(s)
- J Brockmöller
- Department of Clinical Pharmacology, Georg August University of Göttingen, Göttingen, Germany
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