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Ma Y, Wang X, Gou X, Wu X. Identification and characterization of an endogenous biomarker of the renal vectorial transport (OCT2-MATE1). Biopharm Drug Dispos 2024; 45:43-57. [PMID: 38305087 DOI: 10.1002/bdd.2382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/29/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024]
Abstract
The renal tubular organic cation transporter 2 (OCT2) and multidrug and toxin extrusion protein 1 (MATE1) mediate the vectorial elimination of many drugs and toxins from the kidney, and endogenous biomarkers for vectorial transport (OCT2-MATE1) would allow more accurate drug dosing and help to characterize drug-drug interactions and toxicity. Human serum uptake in OCT2-overexpressing cells and metabolomics analysis were carried out. Potential biomarkers were verified in vitro and in vivo. The specificity of biomarkers was validated in renal transporter overexpressing cells and the sensitivity was investigated by Km . The results showed that the uptake of thiamine, histamine, and 5-hydroxytryptamine was significantly increased in OCT2-overexpressing cells. In vitro assays confirmed that thiamine, histamine, and 5-hydroxytryptamine were substrates of both OCT2 and MATE1. In vivo measurements indicated that the serum thiamine level was increased significantly in the presence of the rOCT2 inhibitor cimetidine, and the level in renal tissue was increased significantly by the rMATE1 inhibitor pyrimethamine. There were no significant changes in the uptake or efflux of thiamine in cell lines overexpressed OAT1, OAT2, OAT3, MRP4, organic anion transporting polypeptide 4C1, P-gp, peptide transporter 2, urate transporter 1, and OAT4. The Km for thiamine with OCT2 and MATE1 were 71.2 and 10.8 μM, respectively. In addition, the cumulative excretion of thiamine at 2 and 4 h was strongly correlated with metformin excretion (R2 > 0.6). Thus, thiamine is preferentially secreted by the OCT2 and MATE1 in renal tubules and can provide a reference value for evaluating the function of the renal tubular OCT2-MATE1.
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Affiliation(s)
- Yanrong Ma
- The First Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Xinyi Wang
- The First Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Xueyan Gou
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Xinan Wu
- The First Clinical Medical School, Lanzhou University, Lanzhou, China
- School of Pharmacy, Lanzhou University, Lanzhou, China
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van Hoogdalem E, Smith KL, Hartstra J, Constant J. Rethinking, reducing, and refining the classical oral tyramine challenge test of monoamine oxidase (MAO) inhibitors. Clin Transl Sci 2023; 16:2058-2069. [PMID: 37596819 PMCID: PMC10582662 DOI: 10.1111/cts.13612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/05/2023] [Accepted: 08/02/2023] [Indexed: 08/20/2023] Open
Abstract
The oral tyramine challenge evaluates the safety of novel monoamine oxidase (MAO) inhibitors when taken with tyramine-containing food or drinks. In its current design, it comprises an extensive series of tyramine escalation steps until a blood pressure threshold is met. Due to the high variation in tyramine bioavailability, and thereby in blood pressure effect, this classical design has various limitations, including safety concerns. Based on data from a previously performed tyramine challenge study, the present study explored a reduced new design that escalates up to 400 mg, and evaluates the dose to a tyramine peak plasma concentration of ≥10 ng/mL, instead of a dose up to 800 mg, and to a blood pressure change of ≥30 mm Hg. Tested by trial simulation, the new design proves more efficient than the classical design in terms of better identifying tyramine sensitivity of test and reference treatments and reducing false-positive and false-negative rates in estimating tyramine sensitivity by more than 10-fold. Since it escalates over a lower tyramine dose range, the new design reduces risk to subjects associated with tyramine-induced blood pressure excursions, is less demanding for study participants, and is more efficient. By its focus on tyramine bioavailability as the primary concern for novel MAO inhibitors, the new tyramine challenge study provides better answers in a simplified and safer design compared with the classical design in trial simulation, warranting its use in future clinical studies.
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Affiliation(s)
| | | | - Jan Hartstra
- Drug Development Solutions – PharmacokineticsICONGroningenThe Netherlands
| | - John Constant
- Scientific AffairsICONVictoriaBritish ColumbiaCanada
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3
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Ranganath L, Khedr M, Milan AM, Davison AS, Norman BP, Janssen MCH, Lock E, Bou‐Gharios G, Gallagher JA. Increased prevalence of Parkinson's disease in alkaptonuria. JIMD Rep 2023; 64:282-292. [PMID: 37404676 PMCID: PMC10315388 DOI: 10.1002/jmd2.12367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 04/27/2023] [Indexed: 07/06/2023] Open
Abstract
Amongst a cohort of 88 alkaptonuria (AKU) patients attending the United Kingdom National Alkaptonuria Centre (NAC), four unrelated patients had co-existing Parkinson's disease (PD). Two of the NAC patients developed PD before receiving nitisinone (NIT) while the other two developed overt PD during NIT therapy. NIT lowers redox-active homogentisic acid (HGA) and profoundly increases tyrosine (TYR). A further unpublished case of a Dutch patient with AKU and PD on deep brain stimulation is included in this report. A Pubmed search revealed a further five AKU patients with PD, all without NIT usage. The prevalence of PD in AKU in the NAC appears to be nearly 20-times higher than in the non-AKU population (p < 0.001) even when adjusted for age. We propose that life-long exposure to redox-active HGA may account for the higher prevalence of PD in AKU. Furthermore, the appearance of PD in AKU patients during NIT therapy may be due to unmasking dopamine deficiency in susceptible individuals, as a result of the tyrosinaemia during NIT therapy inhibiting the rate-limiting brain tyrosine hydroxylase.
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Affiliation(s)
- Lakshminarayan Ranganath
- Department of Clinical Biochemistry and Metabolic MedicineRoyal Liverpool University HospitalLiverpoolUK
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical SciencesUniversity of LiverpoolLiverpoolUK
| | - Milad Khedr
- Department of Clinical Biochemistry and Metabolic MedicineRoyal Liverpool University HospitalLiverpoolUK
| | - Anna M. Milan
- Department of Clinical Biochemistry and Metabolic MedicineRoyal Liverpool University HospitalLiverpoolUK
| | - Andrew S. Davison
- Department of Clinical Biochemistry and Metabolic MedicineRoyal Liverpool University HospitalLiverpoolUK
| | - Brendan P. Norman
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical SciencesUniversity of LiverpoolLiverpoolUK
| | - Mirian C. H. Janssen
- Departments of Internal Medicine & PediatricsRadboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Edward Lock
- School of Pharmacy and Biomolecular SciencesLiverpool John Moores UniversityLiverpoolUK
| | - George Bou‐Gharios
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical SciencesUniversity of LiverpoolLiverpoolUK
| | - James A. Gallagher
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical SciencesUniversity of LiverpoolLiverpoolUK
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Van den Eynde V, Gillman PK, Blackwell BB. The Prescriber's Guide to the MAOI Diet-Thinking Through Tyramine Troubles. PSYCHOPHARMACOLOGY BULLETIN 2022; 52:73-116. [PMID: 35721816 PMCID: PMC9172554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This review article features comprehensive discussions on the dietary restrictions issued to patients taking a classic monoamine oxidase inhibitor (phenelzine, tranylcypromine, isocarboxazid), or high-dose (oral or transdermal) selegiline. It equips doctors with the knowledge to explain to their patients which dietary precautions are necessary, and why that is so: MAOIs alter the capacity to metabolize certain monoamines, like tyramine, which causes dose-related blood pressure elevations. Modern food production and hygiene standards have resulted in large reductions of tyramine concentrations in most foodstuffs and beverages, including many cheeses. Thus, the risk of consequential blood pressure increases is considerably reduced-but some caution remains warranted. The effects of other relevant biogenic amines (histamine, dopamine), and of the amino acids L-dopa and L-tryptophan are also discussed. The tables of tyramine data usually presented in MAOI diet guides are by nature unhelpful and imprecise, because tyramine levels vary widely within foods of the same category. For this reason, it is vital that doctors understand the general principles outlined in this guide; that way, they can tailor their instructions and advice to the individual, to his/her lifestyle and situation. This is important because the pressor response is characterized by significant interpatient variability. When all factors are weighed and balanced, the conclusion is that the MAOI diet is not all that difficult. Minimizing the intake of the small number of risky foods is all that is required. Many patients may hardly need to change their diet at all.
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Affiliation(s)
- Vincent Van den Eynde
- Van den Eynde, External Research Consultant for PsychoTropical Research, NeuraWell Therapeutics, Aristo Pharma GmbH. Gillman, Director of PsychoTropical Research and MAOI Expert Group Convener. Blackwell, Retired Professor and Chair of Psychiatry at the Milwaukee Campus of the University of Wisconsin School of Medicine
| | - Peter Kenneth Gillman
- Van den Eynde, External Research Consultant for PsychoTropical Research, NeuraWell Therapeutics, Aristo Pharma GmbH. Gillman, Director of PsychoTropical Research and MAOI Expert Group Convener. Blackwell, Retired Professor and Chair of Psychiatry at the Milwaukee Campus of the University of Wisconsin School of Medicine
| | - Barry B Blackwell
- Van den Eynde, External Research Consultant for PsychoTropical Research, NeuraWell Therapeutics, Aristo Pharma GmbH. Gillman, Director of PsychoTropical Research and MAOI Expert Group Convener. Blackwell, Retired Professor and Chair of Psychiatry at the Milwaukee Campus of the University of Wisconsin School of Medicine
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Rottinghaus AG, Xi C, Amrofell MB, Yi H, Moon TS. Engineering ligand-specific biosensors for aromatic amino acids and neurochemicals. Cell Syst 2022; 13:204-214.e4. [PMID: 34767760 PMCID: PMC8930536 DOI: 10.1016/j.cels.2021.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/08/2021] [Accepted: 10/20/2021] [Indexed: 01/09/2023]
Abstract
Microbial biosensors have diverse applications in metabolic engineering and medicine. Specific and accurate quantification of chemical concentrations allows for adaptive regulation of enzymatic pathways and temporally precise expression of diagnostic reporters. Although biosensors should differentiate structurally similar ligands with distinct biological functions, such specific sensors are rarely found in nature and challenging to create. Using E. coli Nissle 1917, a generally regarded as safe microbe, we characterized two biosensor systems that promiscuously recognize aromatic amino acids or neurochemicals. To improve the sensors' selectivity and sensitivity, we applied rational protein engineering by identifying and mutagenizing amino acid residues and successfully demonstrated the ligand-specific biosensors for phenylalanine, tyrosine, phenylethylamine, and tyramine. Additionally, our approach revealed insights into the uncharacterized structure of the FeaR regulator, including critical residues in ligand binding. These results lay the groundwork for developing kinetically adaptive microbes for diverse applications. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Austin G Rottinghaus
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Chenggang Xi
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Matthew B Amrofell
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Hyojeong Yi
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, USA.
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Overlap and Specificity in the Substrate Spectra of Human Monoamine Transporters and Organic Cation Transporters 1, 2, and 3. Int J Mol Sci 2021; 22:ijms222312816. [PMID: 34884618 PMCID: PMC8657982 DOI: 10.3390/ijms222312816] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/24/2021] [Accepted: 11/24/2021] [Indexed: 12/23/2022] Open
Abstract
Human monoamine transporters (MATs) are cation transporters critically involved in neuronal signal transmission. While inhibitors of MATs have been intensively studied, their substrate spectra have received far less attention. Polyspecific organic cation transporters (OCTs), predominantly known for their role in hepatic and renal drug elimination, are also expressed in the central nervous system and might modulate monoaminergic signaling. Using HEK293 cells overexpressing MATs or OCTs, we compared uptake of 48 compounds, mainly phenethylamine and tryptamine derivatives including matched molecular pairs, across noradrenaline, dopamine and serotonin transporters and OCTs (1, 2, and 3). Generally, MATs showed surprisingly high transport activities for numerous analogs of neurotransmitters, but their substrate spectra were limited by molar mass. Human OCT2 showed the broadest substrate spectrum, and also the highest overlap with MATs substrates. Comparative kinetic analyses revealed that the radiotracer meta-iodobenzylguanidine had the most balanced uptake across all six transporters. Matched molecular pair analyses comparing MAT and OCT uptake using the same methodology could provide a better understanding of structural determinants for high cell uptake by MATs or OCTs. The data may result in a better understanding of pharmacokinetics and toxicokinetics of small molecular organic cations and, possibly, in the development of more specific radiotracers for MATs.
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The trace amine theory of spontaneous hypertension as induced by classic monoamine oxidase inhibitors. J Neural Transm (Vienna) 2021; 128:1741-1756. [PMID: 34373944 DOI: 10.1007/s00702-021-02399-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
The classic monoamine oxidase inhibitors (MAOIs) tranylcypromine (TCP) and phenelzine (PLZ) are powerful antidepressants that come with an equally powerful stigma, and are thus rarely prescribed-despite their well-established effectiveness. Some of these preconceptions appear to stem from unclarity, as the etiology of a rare but important side effect, 'spontaneous hypertension' (SH)-a significant increase in blood pressure absent dietary tyramine ingestion-remains improperly elucidated. This paper aims at uprooting some of the stigma surrounding MAOIs by advancing the trace amine (TA) theory as the causative underpinning of SH. This theory posits that SH results from the considerable influx of TAs observed following TCP- or PLZ-administration. TAs are known, albeit at greatly supraphysiological levels, to raise blood pressure on account of their propensity to exert potent indirect sympathomimetic effects; additionally, some research posits that TAs may induce vasoconstrictive effects partly or wholly separate therefrom, which would then constitute a second hypertensive mechanism. TAs are endogenous to the human body in low quantities. Both TCP and PLZ cause marked elevations of 2-phenylethylamine (PEA), meta- and para-tyramine (m-/p-TYR), octopamine (OA), and tryptamine (TRYP), following both acute and (sub)chronic administration. This paper holds that TYR plays a pivotal role in causing SH, due to its strong pressor effect. Cautious treatment of SH is advised, given its typically self-limiting nature. The risk of hypotensive overshoots must be taken into account. For severe cases, this paper urges reconsideration, following suitable confirmation trials, of antipsychotics (notably risperidone) as these agents may reduce striatal p-TYR levels.
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The impact of cell-free supernatants of Lactococcus lactis subsp. lactis strains on the tyramine formation of Lactobacillus and Lactiplantibacillus strains isolated from cheese and beer. Food Microbiol 2021; 99:103813. [PMID: 34119100 DOI: 10.1016/j.fm.2021.103813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/24/2020] [Accepted: 04/12/2021] [Indexed: 11/23/2022]
Abstract
Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L-1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) - even suppressing it completely in some cases - in four of the six tested tyramine producing strains.
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Zaidi SF, Mgarry R, Alsanea A, Almutairi SK, Alsinnari Y, Alsobaei S, Ahmed K. A Questionnaire-Based Survey to Assess the Level of Knowledge and Awareness about Drug-Food Interactions among General Public in Western Saudi Arabia. PHARMACY 2021; 9:pharmacy9020076. [PMID: 33917944 PMCID: PMC8167613 DOI: 10.3390/pharmacy9020076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 11/16/2022] Open
Abstract
Introduction: Various drug-food interactions exist that may hinder treatment and can sometimes be lethal. Our aim was to assess the level of public knowledge and awareness in Jeddah city, Western Saudi Arabia, about drug-food interactions, along with the effects of demographics on their knowledge. Methods: A survey questionnaire was administered in this cross-sectional study to participants spread across multiple locations in Jeddah, including in malls and public gatherings. Participants included both males and females. Sample size was calculated through Raosoft® software. Data analysis was executed using IBM Statistic SPSS and the level of statistical significance was set at p < 0.05. Results: A total of 410 people participated in the study and only 92.68% (380) of responses were enrolled in the study; 7.32% (30) were not enrolled due to the exclusion criteria. Surprisingly, only six out of eighteen questions regarding drug-food interactions in the administered questionnaire were correctly answered by 380 participants. Data indicated that the participants had a poor to intermediate level of both knowledge and awareness with respect to drug-food interactions. Furthermore, participants showed moderate to strong awareness of the effects of alcohol and tea generally, and their interaction with medication. Conclusion: Participants in our study showed inadequate knowledge of basic and fundamental information about drug-food interactions, which highlights the dire need to increase awareness.
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Affiliation(s)
- Syed Faisal Zaidi
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
- Department of Pharmacology, School of Medicine, Batterjee Medical College for Sciences and Technology, Jeddah 21442, Saudi Arabia
- Correspondence: ; Tel.: +966-553543869
| | - Rayan Mgarry
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
| | - Abdullah Alsanea
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
| | - Sakar Khalid Almutairi
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
| | - Yaser Alsinnari
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
| | - Saad Alsobaei
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
| | - Kanwal Ahmed
- College of Medicine, King Saud bin Abdulaziz University for Health Science, Jeddah 21423, Saudi Arabia; (R.M.); (A.A.); (S.K.A.); (Y.A.); (S.A.); (K.A.)
- Fakeeh College for Medical Sciences, Jeddah 21461, Saudi Arabia
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Jensen O, Rafehi M, Gebauer L, Brockmöller J. Cellular Uptake of Psychostimulants - Are High- and Low-Affinity Organic Cation Transporters Drug Traffickers? Front Pharmacol 2021; 11:609811. [PMID: 33551812 PMCID: PMC7854383 DOI: 10.3389/fphar.2020.609811] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022] Open
Abstract
Psychostimulants are used therapeutically and for illegal recreational purposes. Many of these are inhibitors of the presynaptic noradrenaline, dopamine, and serotonin transporters (NET, DAT, and SERT). According to their physicochemical properties, some might also be substrates of polyspecific organic cation transporters (OCTs) that mediate uptake in liver and kidneys for metabolism and excretion. OCT1 is genetically highly polymorphic, with strong effects on transporter activity and expression. To study potential interindividual differences in their pharmacokinetics, 18 psychostimulants and hallucinogens were assessed in vitro for transport by different OCTs as well as by the high-affinity monoamine transporters NET, DAT, and SERT. The hallucinogenic natural compound mescaline was found to be strongly transported by wild-type OCT1 with a Km of 24.3 µM and a vmax of 642 pmol × mg protein−1 × min−1. Transport was modestly reduced in variants *2 and *7, more strongly reduced in *3 and *4, and lowest in *5 and *6, while *8 showed a moderately increased transport capacity. The other phenylethylamine derivatives methamphetamine, para-methoxymethamphetamine, (-)-ephedrine, and cathine ((+)-norpseudoephedrine), as well as dimethyltryptamine, were substrates of OCT2 with Km values in the range of 7.9–46.0 µM and vmax values between 70.7 and 570 pmol × mg protein−1 × min−1. Affinities were similar or modestly reduced and the transport capacities were reduced down to half in the naturally occurring variant A270S. Cathine was found to be a substrate for NET and DAT, with the Km being 21-fold and the vmax 10-fold higher for DAT but still significantly lower compared to OCT2. This study has shown that several psychostimulants and hallucinogens are substrates for OCTs. Given the extensive cellular uptake of mescaline by the genetically highly polymorphic OCT1, strong interindividual variation in the pharmacokinetics of mescaline might be possible, which could be a reason for highly variable adverse reactions. The involvement of the polymorphic OCT2 in the renal excretion of several psychostimulants could be one reason for individual differences in toxicity.
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Affiliation(s)
- Ole Jensen
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Muhammad Rafehi
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Lukas Gebauer
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
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Woodfin M, Bickel L, Deininger M. Imatinib, cheese and migraines. Leuk Lymphoma 2020; 62:746-748. [PMID: 33112162 DOI: 10.1080/10428194.2020.1839652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Michael Woodfin
- University of Washington School of Medicine, Seattle, WA, USA
| | - Laura Bickel
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA.,Division of Hematology and Hematologic Malignancies, University of Utah, Salt Lake City, UT, USA
| | - Michael Deininger
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA.,Division of Hematology and Hematologic Malignancies, University of Utah, Salt Lake City, UT, USA
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