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Awasthi N, Darman L, Schwarz MA, Schwarz RE. Telotristat ethyl, a tryptophan hydroxylase inhibitor, enhances antitumor efficacy of standard chemotherapy in preclinical cholangiocarcinoma models. J Cell Mol Med 2024; 28:e18585. [PMID: 39223878 PMCID: PMC11369204 DOI: 10.1111/jcmm.18585] [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: 03/28/2024] [Revised: 07/17/2024] [Accepted: 07/25/2024] [Indexed: 09/04/2024] Open
Abstract
Cholangiocarcinoma (CCA), an aggressive biliary tract cancer, carries a grim prognosis with a 5-year survival rate of 5%-15%. Standard chemotherapy regimens for CCA, gemcitabine plus cisplatin (GemCis) or its recently approved combination with durvalumab demonstrate dismal clinical activity, yielding a median survival of 12-14 months. Increased serotonin accumulation and secretion have been implicated in the oncogenic activity of CCA. This study investigated the therapeutic efficacy of telotristat ethyl (TE), a tryptophan hydroxylase inhibitor blocking serotonin biosynthesis, in combination with standard chemotherapies in preclinical CCA models. Nab-paclitaxel (NPT) significantly enhanced animal survival (60%), surpassing the marginal effects of TE (11%) or GemCis (9%) in peritoneal dissemination xenografts. Combining TE with GemCis (26%) or NPT (68%) further increased survival rates. In intrahepatic (iCCA), distal (dCCA) and perihilar (pCCA) subcutaneous xenografts, TE exhibited substantial tumour growth inhibition (41%-53%) compared to NPT (56%-69%) or GemCis (37%-58%). The combination of TE with chemotherapy demonstrated enhanced tumour growth inhibition in all three cell-derived xenografts (67%-90%). PDX studies revealed TE's marked inhibition of tumour growth (40%-73%) compared to GemCis (80%-86%) or NPT (57%-76%). Again, combining TE with chemotherapy exhibited an additive effect. Tumour cell proliferation reduction aligned with tumour growth inhibition in all CDX and PDX tumours. Furthermore, TE treatment consistently decreased serotonin levels in all tumours under all therapeutic conditions. This investigation decisively demonstrated the antitumor efficacy of TE across a spectrum of CCA preclinical models, suggesting that combination therapies involving TE, particularly for patients exhibiting serotonin overexpression, hold the promise of improving clinical CCA therapy.
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Affiliation(s)
- Niranjan Awasthi
- Department of SurgeryIndiana University School of MedicineSouth BendIndianaUSA
- Harper Cancer Research InstituteUniversity of Notre DameNotre DameIndianaUSA
| | - Lily Darman
- Harper Cancer Research InstituteUniversity of Notre DameNotre DameIndianaUSA
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Margaret A. Schwarz
- Harper Cancer Research InstituteUniversity of Notre DameNotre DameIndianaUSA
- Department of PediatricsIndiana University School of MedicineSouth BendIndianaUSA
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Sikiric P, Boban Blagaic A, Strbe S, Beketic Oreskovic L, Oreskovic I, Sikiric S, Staresinic M, Sever M, Kokot A, Jurjevic I, Matek D, Coric L, Krezic I, Tvrdeic A, Luetic K, Batelja Vuletic L, Pavic P, Mestrovic T, Sjekavica I, Skrtic A, Seiwerth S. The Stable Gastric Pentadecapeptide BPC 157 Pleiotropic Beneficial Activity and Its Possible Relations with Neurotransmitter Activity. Pharmaceuticals (Basel) 2024; 17:461. [PMID: 38675421 PMCID: PMC11053547 DOI: 10.3390/ph17040461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/24/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
We highlight the particular aspects of the stable gastric pentadecapeptide BPC 157 pleiotropic beneficial activity (not destroyed in human gastric juice, native and stable in human gastric juice, as a cytoprotection mediator holds a response specifically related to preventing or recovering damage as such) and its possible relations with neurotransmitter activity. We attempt to resolve the shortage of the pleiotropic beneficial effects of BPC 157, given the general standard neurotransmitter criteria, in classic terms. We substitute the lack of direct conclusive evidence (i.e., production within the neuron or present in it as a precursor molecule, released eliciting a response on the receptor on the target cells on neurons and being removed from the site of action once its signaling role is complete). This can be a network of interconnected evidence, previously envisaged in the implementation of the cytoprotection effects, consistent beneficial particular evidence that BPC 157 therapy counteracts dopamine, serotonin, glutamate, GABA, adrenalin/noradrenalin, acetylcholine, and NO-system disturbances. This specifically includes counteraction of those disturbances related to their receptors, both blockade and over-activity, destruction, depletion, tolerance, sensitization, and channel disturbances counteraction. Likewise, BPC 157 activates particular receptors (i.e., VGEF and growth hormone). Furthermore, close BPC 157/NO-system relations with the gasotransmitters crossing the cell membrane and acting directly on molecules inside the cell may envisage particular interactions with receptors on the plasma membrane of their target cells. Finally, there is nerve-muscle relation in various muscle disturbance counteractions, and nerve-nerve relation in various encephalopathies counteraction, which is also exemplified specifically by the BPC 157 therapy application.
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Affiliation(s)
- Predrag Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Lidija Beketic Oreskovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Ivana Oreskovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Suncana Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mario Staresinic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Marko Sever
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Antonio Kokot
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Anatomy and Neuroscience, School of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Ivana Jurjevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Danijel Matek
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Luka Coric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Ante Tvrdeic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Kresimir Luetic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
| | - Lovorka Batelja Vuletic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Predrag Pavic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Tomislav Mestrovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Anatomy and Neuroscience, School of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Ivica Sjekavica
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Diagnostic and Interventional Radiology, Sestre Milosrdnice University Hospital Center, 10000 Zagreb, Croatia
| | - Anita Skrtic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sven Seiwerth
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (A.B.B.); (S.S.); (L.B.O.); (I.O.); (S.S.); (M.S.); (M.S.); (A.K.); (I.J.); (D.M.); (L.C.); (I.K.); (A.T.); (K.L.); (L.B.V.); (P.P.); (T.M.); (I.S.); (S.S.)
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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Sikiric P, Gojkovic S, Krezic I, Smoday IM, Kalogjera L, Zizek H, Oroz K, Vranes H, Vukovic V, Labidi M, Strbe S, Baketic Oreskovic L, Sever M, Tepes M, Knezevic M, Barisic I, Blagaic V, Vlainic J, Dobric I, Staresinic M, Skrtic A, Jurjevic I, Boban Blagaic A, Seiwerth S. Stable Gastric Pentadecapeptide BPC 157 May Recover Brain-Gut Axis and Gut-Brain Axis Function. Pharmaceuticals (Basel) 2023; 16:ph16050676. [PMID: 37242459 DOI: 10.3390/ph16050676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/12/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Conceptually, a wide beneficial effect, both peripherally and centrally, might have been essential for the harmony of brain-gut and gut-brain axes' function. Seen from the original viewpoint of the gut peptides' significance and brain relation, the favorable stable gastric pentadecapeptide BPC 157 evidence in the brain-gut and gut-brain axes' function might have been presented as a particular interconnected network. These were the behavioral findings (interaction with main systems, anxiolytic, anticonvulsive, antidepressant effect, counteracted catalepsy, and positive and negative schizophrenia symptoms models). Muscle healing and function recovery appeared as the therapeutic effects of BPC 157 on the various muscle disabilities of a multitude of causes, both peripheral and central. Heart failure was counteracted (including arrhythmias and thrombosis), and smooth muscle function recovered. These existed as a multimodal muscle axis impact on muscle function and healing as a function of the brain-gut axis and gut-brain axis as whole. Finally, encephalopathies, acting simultaneously in both the periphery and central nervous system, BPC 157 counteracted stomach and liver lesions and various encephalopathies in NSAIDs and insulin rats. BPC 157 therapy by rapidly activated collateral pathways counteracted the vascular and multiorgan failure concomitant to major vessel occlusion and, similar to noxious procedures, reversed initiated multicausal noxious circuit of the occlusion/occlusion-like syndrome. Severe intracranial (superior sagittal sinus) hypertension, portal and caval hypertensions, and aortal hypotension were attenuated/eliminated. Counteracted were the severe lesions in the brain, lungs, liver, kidney, and gastrointestinal tract. In particular, progressing thrombosis, both peripherally and centrally, and heart arrhythmias and infarction that would consistently occur were fully counteracted and/or almost annihilated. To conclude, we suggest further BPC 157 therapy applications.
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Affiliation(s)
- Predrag Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Slaven Gojkovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Maria Smoday
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Luka Kalogjera
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Helena Zizek
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Katarina Oroz
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Hrvoje Vranes
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Vlasta Vukovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - May Labidi
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | | | - Marko Sever
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Marijan Tepes
- Department of Clinical Medicine, Faculty of Dental Medicine and Health, University of Osijek, 31000 Osijek, Croatia
| | - Mario Knezevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Barisic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Vladimir Blagaic
- Department of Obstetrics and Gynecology, Clinical Hospital Sveti Duh, 10000 Zagreb, Croatia
| | - Josipa Vlainic
- Laboratory for Advanced Genomics, Division of Molecular Medicine, lnstitute Ruder Boskovic, 10000 Zagreb, Croatia
| | - Ivan Dobric
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mario Staresinic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Anita Skrtic
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivana Jurjevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sven Seiwerth
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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Kinney KR, Hanlon CA. Changing Cerebral Blood Flow, Glucose Metabolism, and Dopamine Binding Through Transcranial Magnetic Stimulation: A Systematic Review of Transcranial Magnetic Stimulation-Positron Emission Tomography Literature. Pharmacol Rev 2022; 74:918-932. [PMID: 36779330 PMCID: PMC9580100 DOI: 10.1124/pharmrev.122.000579] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 11/22/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. Despite its widespread use, we have an incomplete understanding of the way in which acute and chronic sessions of TMS affect various neural and vascular systems. This systematic review summarizes the state of our knowledge regarding the effects TMS may be having on cerebral blood flow, glucose metabolism, and neurotransmitter release. Forty-five studies were identified. Several key themes emerged: 1) TMS transiently increases cerebral blood flow in the area under the coil; 2) TMS to the prefrontal cortex increases glucose metabolism in the anterior cingulate cortex of patients with depression; and 3) TMS to the motor cortex and prefrontal cortex decreases dopamine receptor availability in the ipsilateral putamen and caudate respectively. There is, however, a paucity of literature regarding the effects TMS may have on other neurotransmitter and neuropeptide systems of interest, all of which may shed vital light on existing biologic mechanisms and future therapeutic development. SIGNIFICANCE STATEMENT: Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. This systematic review summarizes the state of our knowledge regarding the effects TMS on cerebral blood flow, glucose metabolism, and neurotransmitter release.
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Affiliation(s)
- Kaitlin R Kinney
- Department of Cancer Biology (K.R.K., C.A.H.) and Department of Physiology and Pharmacology (C.A.H.), Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Colleen A Hanlon
- Department of Cancer Biology (K.R.K., C.A.H.) and Department of Physiology and Pharmacology (C.A.H.), Wake Forest School of Medicine, Winston-Salem, North Carolina
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5-HT Receptors and the Development of New Antidepressants. Int J Mol Sci 2021; 22:ijms22169015. [PMID: 34445721 PMCID: PMC8396477 DOI: 10.3390/ijms22169015] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 02/06/2023] Open
Abstract
Serotonin modulates several physiological and cognitive pathways throughout the human body that affect emotions, memory, sleep, and thermal regulation. The complex nature of the serotonergic system and interactions with other neurochemical systems indicate that the development of depression may be mediated by various pathomechanisms, the common denominator of which is undoubtedly the disturbed transmission in central 5-HT synapses. Therefore, the deliberate pharmacological modulation of serotonergic transmission in the brain seems to be one of the most appropriate strategies for the search for new antidepressants. As discussed in this review, the serotonergic system offers great potential for the development of new antidepressant therapies based on the combination of SERT inhibition with different pharmacological activity towards the 5-HT system. The aim of this article is to summarize the search for new antidepressants in recent years, focusing primarily on the possibility of benefiting from interactions with various 5-HT receptors in the pharmacotherapy of depression.
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Fluorine-18-Labeled PET Radiotracers for Imaging Tryptophan Uptake and Metabolism: a Systematic Review. Mol Imaging Biol 2021; 22:805-819. [PMID: 31512038 DOI: 10.1007/s11307-019-01430-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Due to its metabolism via the serotonin and kynurenine pathways, tryptophan plays a key role in multiple disease processes including cancer. Imaging tryptophan uptake and metabolism in vivo can be achieved with tryptophan derivative positron emission tomography (PET) radiotracers. While human studies with such tracers have been confined to C-11-labeled compounds, preclinical development of F-18-labeled tryptophan-based radiotracers has surged in recent years. We performed a systematic review of studies reporting on such F-18-labeled tryptophan tracers to summarize and compare their biological characteristics and their potential for tumor imaging, with a particular focus on key enzymes of the kynurenine pathway (indoleamine 2,3-dioxygenase [IDO] and tryptophan 2,3-dioxygenase [TDO]), which play an important role in tumoral immune resistance. From a PubMed search, English language articles including data on the preparation and radiochemical and/or biological characteristics of F-18-labeled tryptophan derivative radiotracers were reviewed. A total of 19 original papers included data on 15 unique radiotracers, the majority of which were synthesized with an adequate radiochemical yield. Automated synthesis was reported for 1-(2-[18F]fluoroethyl)-L-tryptophan, the most extensively evaluated tracer thus far. Biodistribution studies showed high uptake in the pancreas, while the L-type amino acid transporter was the dominant transport mechanism for most of the reviewed tracers. Tracers tested for tumor uptake showed accumulation in tumor cell lines in vitro and in xenografts in vivo, often with favorable tumor-to-background uptake ratios in comparison with clinically used F-18-labeled radiotracers. Five tracers showed promise for imaging IDO activity, including 1-(2-[18F]fluoroethyl)-L-tryptophan and a F-18-labeled analog of alpha-[11C]methyl-L-tryptophan tested clinically in previous studies. Two radiotracers were metabolized by TDO but showed defluorination in vivo. In summary, most F-18-labeled tryptophan derivative PET tracers share common transport mechanisms and biodistribution characteristics. Several reported tracers could be candidates for further testing and validation toward PET imaging applications in a variety of human diseases.
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α-Methyl-l-tryptophan as a weight-loss agent in multiple models of obesity in mice. Biochem J 2021; 478:1347-1358. [PMID: 33720280 PMCID: PMC8038855 DOI: 10.1042/bcj20210100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 01/13/2023]
Abstract
α-Methyl-L-tryptophan (α-MLT) is currently in use as a tracer in its 11C-labeled form to monitor the health of serotonergic neurons in humans. In the present study, we found this compound to function as an effective weight-loss agent at pharmacological doses in multiple models of obesity in mice. The drug was able to reduce the body weight when given orally in drinking water (1 mg/ml) in three different models of obesity: normal mice on high-fat diet, Slc6a14-null mice on high-fat diet, and ob/ob mice on normal diet. Only the l-enantiomer (α-MLT) was active while the d-enantiomer (α-MDT) had negligible activity. The weight-loss effect was freely reversible, with the weight gain resuming soon after the withdrawal of the drug. All three models of obesity were associated with hyperglycemia, insulin resistance, and hepatic steatosis; α-MLT reversed these features. There was a decrease in food intake in the treatment group. Mice on a high-fat diet showed decreased cholesterol and protein in the serum when treated with α-MLT; there was however no evidence of liver and kidney dysfunction. Plasma amino acid profile indicated a significant decrease in the levels of specific amino acids, including tryptophan; but the levels of arginine were increased. We conclude that α-MLT is an effective, reversible, and orally active drug for the treatment of obesity and metabolic syndrome.
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Metz DC, Liu E, Joish VN, Huynh L, Totev TI, Duh MS, Seth K, Giacalone S, Lapuerta P, Morse MA. Survival and Clinical Outcomes with Telotristat Ethyl in Patients with Carcinoid Syndrome. Cancer Manag Res 2020; 12:9713-9719. [PMID: 33116830 PMCID: PMC7548219 DOI: 10.2147/cmar.s276519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022] Open
Abstract
Purpose The TELEACE study showed reductions in tumor size in patients with neuroendocrine tumors, receiving telotristat ethyl in US clinical practice. Here, we report progression-free survival, time to tumor progression, changes in carcinoid syndrome symptoms, and indictors of overall health. Patients and Methods This was a retrospective, single arm, pre-post medical chart review of patients with locally advanced or metastatic neuroendocrine tumors and documented carcinoid syndrome receiving telotristat ethyl for at least 6 months. Patients with poorly differentiated tumors, mixed tumor types or conflicting clinical trial enrollment were excluded. Descriptive statistics, Kaplan–Meier and chi-square tests were used to evaluate PFS, tumor progression, changes in symptoms, body weight and ECOG performance status before and after telotristat ethyl initiation. Subgroup analyses were conducted in patients with the same pre- and post-telotristat ethyl background treatment. Results Anonymized data for 200 patients were provided by 114 physicians; patients received telotristat ethyl for a median of 9 months. Median time to tumor progression was 39.8 months (IQR, 18.7–39.8); most had no tumor progression at 6 (92%) and 12 months (87%). Median progression-free survival was 23.7 months (17.8–39.8); most had progression-free survival at 6 (90%) and 12 months (80%). Results were consistent in the subgroup of 65 patients with the same pre/post background treatment. Nearly all patients had improved carcinoid syndrome symptoms, stable or improved weight and ECOG performance status. Conclusion Patients showed improvements in clinical outcomes and indicators of overall health following treatment with telotristat ethyl in this exploratory pilot study, consistent with previously observed reductions in tumor size.
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Affiliation(s)
- David C Metz
- Neuroendocrine Tumor Program at Penn Medicine, Philadelphia, PA 19104, USA
| | - Eric Liu
- The Neuroendocrine Institute at Rocky Mountain Cancer Centers, Denver, CO 80218, USA
| | - Vijay N Joish
- Lexicon Pharmaceuticals, Inc, The Woodlands, TX 77831, USA
| | | | | | | | - Kiernan Seth
- Lexicon Pharmaceuticals, Inc, The Woodlands, TX 77831, USA
| | | | - Pablo Lapuerta
- Lexicon Pharmaceuticals, Inc, The Woodlands, TX 77831, USA
| | - Michael A Morse
- Duke Cancer Institute, School of Medicine, Duke University, Durham, NC 27710, USA
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9
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Riblet NB, Gottlieb DJ, Hoyt JE, Watts BV, Shiner B. An analysis of the relationship between chronic obstructive pulmonary disease, smoking and depression in an integrated healthcare system. Gen Hosp Psychiatry 2020; 64:72-79. [PMID: 32279024 DOI: 10.1016/j.genhosppsych.2020.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Chronic Obstructive Pulmonary Disease (COPD) and smoking are highly associated with depression and hypoxia. There is limited knowledge about whether hypoxic conditions interact to cause depression. METHOD A population-based cohort study was conducted using the Veterans Affairs (VA) Corporate Data Warehouse. Patients must have accessed any healthcare at a VA facility between 2004 and 2014 and had a negative depression screen (Patient Health Questionnaire-2 (PHQ-2) score ≤ 2). Patients with COPD or a positive depression screen (PHQ-2 score: 3+) during or prior to the year with a negative depression screen were excluded. Logistic regression with annual observations was used to evaluate depression incidence based on COPD and smoking status. Models were adjusted for demographics and other comorbid conditions. A probability scale was used to examine interactions between COPD and smoking. RESULTS A total of 3,284,496 patients were included. Patients with COPD and current smokers were at increased risk for developing depression. There were minimal interaction effects between COPD and smoking. The odds of developing depression in a year varied from 1.4% among never smokers without COPD to 2.9.% among current smokers with COPD. CONCLUSION Smoking and COPD are independent risk factors for depression and interact to cause depression. Further research is needed to confirm whether hypoxia contributes to this association.
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Affiliation(s)
- Natalie B Riblet
- Veterans Affairs Medical Center, White River Junction, VT, USA; Geisel School of Medicine at Dartmouth College, Hanover, NH, USA; The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH, USA.
| | - Daniel J Gottlieb
- Veterans Affairs Medical Center, White River Junction, VT, USA; The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH, USA.
| | - Jessica E Hoyt
- Veterans Affairs Medical Center, White River Junction, VT, USA.
| | - Bradley V Watts
- VA Office of Systems Redesign and Improvement, White River Junction, VT, USA; Geisel School of Medicine at Dartmouth College, Hanover, NH, USA.
| | - Brian Shiner
- Veterans Affairs Medical Center, White River Junction, VT, USA; National Center for PTSD, White River Junction, VT, USA; Geisel School of Medicine at Dartmouth College, Hanover, NH, USA; The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH, USA.
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10
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Franke M, Conzelmann A, Grünblatt E, Werling AM, Spieles H, Wewetzer C, Warnke A, Romanos M, Walitza S, Renner TJ. No Association of Variants of the NPY-System With Obsessive-Compulsive Disorder in Children and Adolescents. Front Mol Neurosci 2019; 12:112. [PMID: 31133798 PMCID: PMC6511743 DOI: 10.3389/fnmol.2019.00112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 04/17/2019] [Indexed: 01/08/2023] Open
Abstract
Obsessive-compulsive disorder (OCD) causes severe distress and is therefore counted by the World Health Organisation (WHO) as one of the 10 most impairing illnesses. There is evidence for a strong genetic underpinning especially in early onset OCD (eoOCD). Though several genes involved in neurotransmission have been reported as candidates, there is still a need to identify new pathways. In this study, we focussed on genetic variants of the Neuropeptide Y (NPY) system. NPY is one of the most abundant neuropeptides in the human brain with emerging evidence of capacity to modulate stress response, which is of high relevance in OCD. We focussed on tag-SNPs of NPY and its receptor gene NPY1R in a family-based approach. The sample comprised 86 patients (children and adolescents) with eoOCD with both their biological parents. However, this first study on genetic variants of the NPY-system could not confirm the association between the investigated SNPs and eoOCD. Based on the small sample size results have to be interpreted as preliminary and should be replicated in larger samples. However, also in an additional GWAS analysis in a large sample, we could not observe an associations between NPY and OCD. Overall, these preliminary results point to a minor role of NPY on the stress response of OCD.
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Affiliation(s)
- Maximilian Franke
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Annette Conzelmann
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Edna Grünblatt
- University Hospital of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland
| | - Anna M. Werling
- University Hospital of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland
| | - Helen Spieles
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Christoph Wewetzer
- Department of Child and Adolescent Psychiatry and Psychotherapy, Kliniken der Stadt Köln, Cologne, Germany
| | - Andreas Warnke
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Marcel Romanos
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Susanne Walitza
- University Hospital of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland
| | - Tobias J. Renner
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Tübingen, Tübingen, Germany
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11
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Giglio BC, Wang H, Yan X, Li Z. Synthesis and initial evaluation of radioactive 5-I-α-methyl-tryptophan: a Trp based agent targeting IDO-1. MEDCHEMCOMM 2019; 10:814-816. [PMID: 31191872 PMCID: PMC6540958 DOI: 10.1039/c9md00082h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/11/2019] [Indexed: 12/30/2022]
Abstract
A synthetic approach is established to achieve radioactive 5-I-α-methyl-tryptophan (5-I-AMT). An enzyme based assay demonstrated that 5-I-AMT is a substrate of IDO-1. The in vivo distribution and imaging potential of 5-I-AMT were explored with a B16F10 tumor model using I-124 as the radiotag.
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Affiliation(s)
- Benjamin C Giglio
- Department of Radiology and Biomedical Research Imaging Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , USA .
| | - Hui Wang
- Department of Radiology and Biomedical Research Imaging Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , USA .
| | - Xuefeng Yan
- Department of Radiology and Biomedical Research Imaging Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , USA .
| | - Zibo Li
- Department of Radiology and Biomedical Research Imaging Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , USA .
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12
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Hypoxia-related risk factors for death by suicide in a national clinical sample. Psychiatry Res 2019; 273:247-251. [PMID: 30658209 PMCID: PMC8801295 DOI: 10.1016/j.psychres.2019.01.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/11/2018] [Accepted: 01/11/2019] [Indexed: 01/09/2023]
Abstract
The relationship between three markers of chronic hypoxia (altitude, smoking and chronic obstructive pulmonary disease (COPD)) and suicide risk has not been well-studied. We conducted a population-based cohort study evaluating the association between chronic hypoxia and suicide risk. Patients entered the cohort in their first year with a documented healthcare encounter and remained in the cohort until their death or the end of the study period. Generalized estimating equation (GEE) methodology was used to assess the association between suicide and three risk markers of chronic hypoxia. Findings were summarized using odds ratio (OR) and 95% confidence intervals (CI). Among the 9,620,944 patients in the cohort, there were 22,403 suicide deaths. There was a statistically significant progression of suicide risk as altitude rose in increments of 1000 m (OR: 1.22). There was a strong association between the number of hypoxic conditions and the odds of suicide. Patients with three markers of chronic hypoxia was nearly four times more likely to die by suicide than patients with no markers (OR: 3.96). Chronic hypoxia is a risk factor for suicide and having multiple indicators of hypoxia confers a greater risk for suicide, indicating a dose-response relationship.
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13
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Abstract
OBJECTIVE Central nervous system (CNS) serotonin (5-HT) exerts both excitatory and inhibitory effects on the sympathetic nervous system (SNS) in animals. In this study, we examine the effects of tryptophan enhancement and depletion on plasma catecholamine levels in humans. METHODS The total sample consisted of 164 healthy men and women who were tested for 2 days. Seventy-nine participants were randomized to a tryptophan enhancement condition and 85 to a tryptophan depletion condition. Both protocols consisted of a "sham day," followed by an "active day." Blood samples for assessment of plasma norepinephrine and epinephrine levels were collected before and after tryptophan enhancement/depletion. Data were analyzed using general linear models. Separate analyses were conducted for each study arm and for each measure. RESULTS In the depletion condition, both epinephrine (F(5,330) = 2.69, p = .021) and norepinephrine (F(5,335) = 2.79, p = .018) showed small increases on active versus "sham" depletion days. There were also significant day by time interactions for epinephrine (F(3,171) = 39.32, p < .0001) and norepinephrine (F(3,195) = 31.09, p < .0001) levels in the enhancement arm. Tryptophan infusion resulted in a marked increase in epinephrine (Premean = 23.92 (12.23) versus Postmean = 81.57 (62.36)) and decrease in norepinephrine (Premean = 257.2 (106.11) versus Postmean = 177.04 (87.15)), whereas levels of both catecholamines were stable on the "sham day." CONCLUSIONS CNS 5-HT exerts both inhibitory and excitatory effects on SNS activity in humans, potentially due to stimulation of CNS 5-HT receptors that have shown to have inhibitory (5-HT1A) and excitatory (5-HT1A and/or 5-HT2) SNS effects in animal models.
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14
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Nordeman P, Yngve U, Wilking H, Gustavsson SÅ, Eriksson J, Antoni G. Automated GMP-production of α-[ 11 C]methyl-L-tryptophan using a tracer production system (TPS). J Labelled Comp Radiopharm 2018; 61:1106-1109. [PMID: 29902836 DOI: 10.1002/jlcr.3648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 05/07/2018] [Accepted: 06/04/2018] [Indexed: 11/10/2022]
Abstract
The radiosynthesis and GMP validation of [11 C]AMT for human use are described. Three consecutive batches were produced giving 940-3790 MBq (4%-17% RCY, decay corrected, based on [11 C]CO2 ) of the tracer. The molar activity at the end of synthesis was 19 to 35 GBq/μmol, the radiochemical purity was ≥98%, and the enantiomeric purity was >99%. While the synthesis method was automated using a new generation of synthesis equipment, tracer production system developed in house, the method should be readily applicable to other synthesis platforms with minor modifications.
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Affiliation(s)
- Patrik Nordeman
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Ulrika Yngve
- Science for Life Laboratory, Drug Discovery and Development Platform, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Helena Wilking
- Uppsala University Hospital, PET-Centre, Uppsala, Sweden
| | | | - Jonas Eriksson
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Gunnar Antoni
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
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15
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Brain serotonin synthesis capacity in obsessive-compulsive disorder: effects of cognitive behavioral therapy and sertraline. Transl Psychiatry 2018; 8:82. [PMID: 29666372 PMCID: PMC5904107 DOI: 10.1038/s41398-018-0128-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 01/06/2018] [Accepted: 01/31/2018] [Indexed: 02/01/2023] Open
Abstract
Cognitive behavioral therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) are both effective treatments for some patients with obsessive-compulsive disorder (OCD), yet little is known about the neurochemical changes related to these treatment modalities. Here, we used positron emission tomography and the α-[11C]methyl-L-tryptophan tracer to examine the changes in brain regional serotonin synthesis capacity in OCD patients following treatment with CBT or SSRI treatment. Sixteen medication-free OCD patients were randomly assigned to 12 weeks of either CBT or sertraline treatment. Pre-to-post treatment changes in the α-[11C]methyl-L-tryptophan brain trapping constant, K* (ml/g/min), were assessed as a function of symptom response, and correlations with symptom improvement were examined. Responders/partial responders to treatment did not show significant changes in relative regional tracer uptake; rather, in responders/partial responders, 12 weeks of treatment led to serotonin synthesis capacity increases that were brain-wide. Irrespective of treatment modality, baseline serotonin synthesis capacity in the raphe nuclei correlated positively with clinical improvement. These observations suggest that, for some patients, successful remediation of OCD symptoms might be associated with greater serotonergic tone.
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16
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Michelhaugh SK, Muzik O, Guastella AR, Klinger NV, Polin LA, Cai H, Xin Y, Mangner TJ, Zhang S, Juhász C, Mittal S. Assessment of Tryptophan Uptake and Kinetics Using 1-(2-18F-Fluoroethyl)-l-Tryptophan and α-11C-Methyl-l-Tryptophan PET Imaging in Mice Implanted with Patient-Derived Brain Tumor Xenografts. J Nucl Med 2016; 58:208-213. [PMID: 27765857 DOI: 10.2967/jnumed.116.179994] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/14/2016] [Indexed: 11/16/2022] Open
Abstract
Abnormal tryptophan metabolism via the kynurenine pathway is involved in the pathophysiology of a variety of human diseases including cancers. α-11C-methyl-l-tryptophan (11C-AMT) PET imaging demonstrated increased tryptophan uptake and trapping in epileptic foci and brain tumors, but the short half-life of 11C limits its widespread clinical application. Recent in vitro studies suggested that the novel radiotracer 1-(2-18F-fluoroethyl)-l-tryptophan (18F-FETrp) may be useful to assess tryptophan metabolism via the kynurenine pathway. In this study, we tested in vivo organ and tumor uptake and kinetics of 18F-FETrp in patient-derived xenograft mouse models and compared them with 11C-AMT uptake. METHODS Xenograft mouse models of glioblastoma and metastatic brain tumors (from lung and breast cancer) were developed by subcutaneous implantation of patient tumor fragments. Dynamic PET scans with 18F-FETrp and 11C-AMT were obtained for mice bearing human brain tumors 1-7 d apart. The biodistribution and tumoral SUVs for both tracers were compared. RESULTS 18F-FETrp showed prominent uptake in the pancreas and no bone uptake, whereas 11C-AMT showed higher uptake in the kidneys. Both tracers showed uptake in the xenograft tumors, with a plateau of approximately 30 min after injection; however, 18F-FETrp showed higher tumoral SUV than 11C-AMT in all 3 tumor types tested. The radiation dosimetry for 18F-FETrp determined from the mouse data compared favorably with the clinical 18F-FDG PET tracer. CONCLUSION 18F-FETrp tumoral uptake, biodistribution, and radiation dosimetry data provide strong preclinical evidence that this new radiotracer warrants further studies that may lead to a broadly applicable molecular imaging tool to examine abnormal tryptophan metabolism in human tumors.
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Affiliation(s)
| | - Otto Muzik
- Department of Pediatrics, Wayne State University, Detroit, Michigan.,Department of Radiology, Wayne State University, Detroit, Michigan.,PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan
| | - Anthony R Guastella
- Department of Neurosurgery, Wayne State University, Detroit, Michigan.,Department of Oncology, Wayne State University, Detroit, Michigan.,Karmanos Cancer Institute, Detroit, Michigan
| | - Neil V Klinger
- Department of Neurosurgery, Wayne State University, Detroit, Michigan
| | - Lisa A Polin
- Department of Oncology, Wayne State University, Detroit, Michigan.,Karmanos Cancer Institute, Detroit, Michigan
| | - Hancheng Cai
- Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern, Dallas, Texasand
| | - Yangchun Xin
- Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern, Dallas, Texasand
| | - Thomas J Mangner
- Department of Radiology, Wayne State University, Detroit, Michigan.,PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan
| | - Shaohui Zhang
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan
| | - Csaba Juhász
- Department of Pediatrics, Wayne State University, Detroit, Michigan.,PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan.,Karmanos Cancer Institute, Detroit, Michigan.,Department of Neurology, Wayne State University, Detroit, Michigan
| | - Sandeep Mittal
- Department of Neurosurgery, Wayne State University, Detroit, Michigan .,Department of Oncology, Wayne State University, Detroit, Michigan.,Karmanos Cancer Institute, Detroit, Michigan
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17
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Bandelow B, Baldwin D, Abelli M, Altamura C, Dell'Osso B, Domschke K, Fineberg NA, Grünblatt E, Jarema M, Maron E, Nutt D, Pini S, Vaghi MM, Wichniak A, Zai G, Riederer P. Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics. World J Biol Psychiatry 2016; 17:321-65. [PMID: 27403679 DOI: 10.1080/15622975.2016.1181783] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD). METHODS Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network. RESULTS The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition. CONCLUSIONS Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.
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Affiliation(s)
- Borwin Bandelow
- a Department of Psychiatry and Psychotherapy , University of Göttingen , Germany
| | - David Baldwin
- b Faculty of Medicine , University of Southampton , Southampton , UK
| | - Marianna Abelli
- c Department of Clinical and Experimental Medicine , Section of Psychiatry, University of Pisa , Italy
| | - Carlo Altamura
- d Department of Psychiatry , University of Milan; Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico , Milan , Italy
| | - Bernardo Dell'Osso
- d Department of Psychiatry , University of Milan; Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico , Milan , Italy
| | - Katharina Domschke
- e Department of Psychiatry, Psychosomatics and Psychotherapy , University of Wuerzburg , Germany
| | - Naomi A Fineberg
- f Hertfordshire Partnership University NHS Foundation Trust and University of Hertfordshire , Rosanne House, Parkway , Welwyn Garden City , UK
| | - Edna Grünblatt
- e Department of Psychiatry, Psychosomatics and Psychotherapy , University of Wuerzburg , Germany ;,g Neuroscience Center Zurich , University of Zurich and the ETH Zurich , Zürich , Switzerland ;,h Department of Child and Adolescent Psychiatry and Psychotherapy , Psychiatric Hospital, University of Zurich , Zürich , Switzerland ;,i Zurich Center for Integrative Human Physiology , University of Zurich , Switzerland
| | - Marek Jarema
- j Third Department of Psychiatry , Institute of Psychiatry and Neurology , Warszawa , Poland
| | - Eduard Maron
- k North Estonia Medical Centre, Department of Psychiatry , Tallinn , Estonia ;,l Department of Psychiatry , University of Tartu , Estonia ;,m Faculty of Medicine, Department of Medicine, Centre for Neuropsychopharmacology, Division of Brain Sciences , Imperial College London , UK
| | - David Nutt
- m Faculty of Medicine, Department of Medicine, Centre for Neuropsychopharmacology, Division of Brain Sciences , Imperial College London , UK
| | - Stefano Pini
- c Department of Clinical and Experimental Medicine , Section of Psychiatry, University of Pisa , Italy
| | - Matilde M Vaghi
- n Department of Psychology and Behavioural and Clinical Neuroscience Institute , University of Cambridge , UK
| | - Adam Wichniak
- j Third Department of Psychiatry , Institute of Psychiatry and Neurology , Warszawa , Poland
| | - Gwyneth Zai
- n Department of Psychology and Behavioural and Clinical Neuroscience Institute , University of Cambridge , UK ;,o Neurogenetics Section, Centre for Addiction & Mental Health , Toronto , Canada ;,p Frederick W. Thompson Anxiety Disorders Centre, Department of Psychiatry, Sunnybrook Health Sciences Centre , Toronto , Canada ;,q Institute of Medical Science and Department of Psychiatry, University of Toronto , Toronto , Canada
| | - Peter Riederer
- e Department of Psychiatry, Psychosomatics and Psychotherapy , University of Wuerzburg , Germany ;,g Neuroscience Center Zurich , University of Zurich and the ETH Zurich , Zürich , Switzerland ;,h Department of Child and Adolescent Psychiatry and Psychotherapy , Psychiatric Hospital, University of Zurich , Zürich , Switzerland
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18
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Serotonin biosynthesis as a predictive marker of serotonin pharmacodynamics and disease-induced dysregulation. Sci Rep 2016; 6:30059. [PMID: 27444653 PMCID: PMC4956766 DOI: 10.1038/srep30059] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/27/2016] [Indexed: 12/23/2022] Open
Abstract
The biogenic amine serotonin (5-HT) is a multi-faceted hormone that is synthesized from dietary tryptophan with the rate limiting step being catalyzed by the enzyme tryptophan hydroxylase (TPH). The therapeutic potential of peripheral 5-HT synthesis inhibitors has been demonstrated in a number of clinical and pre-clinical studies in diseases including carcinoid syndrome, lung fibrosis, ulcerative colitis and obesity. Due to the long half-life of 5-HT in blood and lung, changes in steady-state levels are slow to manifest themselves. Here, the administration of stable isotope labeled tryptophan (heavy “h-Trp”) and resultant in vivo conversion to h-5-HT is used to monitor 5-HT synthesis in rats. Dose responses for the blockade of h-5-HT appearance in blood with the TPH inhibitors L-para-chlorophenylalanine (30 and 100 mg/kg) and telotristat etiprate (6, 20 and 60 mg/kg), demonstrated that the method enables robust quantification of pharmacodynamic effects on a short time-scale, opening the possibility for rapid screening of TPH1 inhibitors in vivo. In the bleomycin-induced lung fibrosis rat model, the mechanism of lung 5-HT increase was investigated using a combination of synthesis and steady state 5-HT measurement. Elevated 5-HT synthesis measured in the injured lungs was an early predictor of disease induced increases in total 5-HT.
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19
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Deen M, Christensen CE, Hougaard A, Hansen HD, Knudsen GM, Ashina M. Serotonergic mechanisms in the migraine brain - a systematic review. Cephalalgia 2016; 37:251-264. [PMID: 27013238 DOI: 10.1177/0333102416640501] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background Migraine is one of the most common and disabling of all medical conditions, affecting 16% of the general population, causing huge socioeconomic costs globally. Current available treatment options are inadequate. Serotonin is a key molecule in the neurobiology of migraine, but the exact role of brain serotonergic mechanisms remains a matter of controversy. Methods We systematically searched PubMed for studies investigating the serotonergic system in the migraine brain by either molecular neuroimaging or electrophysiological methods. Results The literature search resulted in 59 papers, of which 13 were eligible for review. The reviewed papers collectively support the notion that migraine patients have alterations in serotonergic neurotransmission. Most likely, migraine patients have a low cerebral serotonin level between attacks, which elevates during a migraine attack. Conclusion This review suggests that novel methods of investigating the serotonergic system in the migraine brain are warranted. Uncovering the serotonergic mechanisms in migraine pathophysiology could prove useful for the development of future migraine drugs.
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Affiliation(s)
- Marie Deen
- 1 Danish Headache Center, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark.,2 Neurobiology Research Unit and Center for Experimental Medicine Neuropharmacology, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark.,3 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Casper Emil Christensen
- 1 Danish Headache Center, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark
| | - Anders Hougaard
- 1 Danish Headache Center, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark
| | - Hanne Demant Hansen
- 2 Neurobiology Research Unit and Center for Experimental Medicine Neuropharmacology, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark
| | - Gitte Moos Knudsen
- 2 Neurobiology Research Unit and Center for Experimental Medicine Neuropharmacology, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark.,3 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Messoud Ashina
- 1 Danish Headache Center, Department of Neurology, The Neuroscience Centre, Rigshospitalet, Denmark.,3 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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20
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Kaufman J, DeLorenzo C, Choudhury S, Parsey RV. The 5-HT1A receptor in Major Depressive Disorder. Eur Neuropsychopharmacol 2016; 26:397-410. [PMID: 26851834 PMCID: PMC5192019 DOI: 10.1016/j.euroneuro.2015.12.039] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 02/07/2023]
Abstract
Major Depressive Disorder (MDD) is a highly prevalent psychiatric diagnosis that is associated with a high degree of morbidity and mortality. This debilitating disorder is currently one of the leading causes of disability nationwide and is predicted to be the leading cause of disease burden by the year 2030. A large body of previous research has theorized that serotonergic dysfunction, specifically of the serotonin (5-HT) 1A receptor, plays a key role in the development of MDD. The purpose of this review is to describe the evolution of our current understanding of the serotonin 1A (5-HT1A) receptor and its role in the pathophysiology MDD through the discussion of animal, post-mortem, positron emission tomography (PET), pharmacologic and genetic studies.
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Affiliation(s)
- Joshua Kaufman
- Stony Brook University, Stony Brook, NY 11794, United States.
| | | | - Sunia Choudhury
- Stony Brook University, Stony Brook, NY 11794, United States
| | - Ramin V Parsey
- Stony Brook University, Stony Brook, NY 11794, United States
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21
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Design and automated production of 11C-alpha-methyl-l-tryptophan (11C-AMT). Nucl Med Biol 2016; 43:303-8. [PMID: 27150033 DOI: 10.1016/j.nucmedbio.2016.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/08/2016] [Accepted: 02/10/2016] [Indexed: 11/21/2022]
Abstract
(11)C-alpha-methyl-l-tryptophan ([(11)C]AMT), a tryptophan metabolism PET tracer, has successfully been employed for brain serotonin pathway and indoleamine 2,3-dioxygenase (IDO) pathway related tumor imaging. We here report a reliable, automated procedure for routine synthesis of [(11)C]AMT based on an Eckert and Ziegler Modular-Lab system. The semi-preparative HPLC was incorporated into the system to improve chemical purity and specific activity. The 6-step radiosynthesis followed by HPLC-purification provided [(11)C]AMT in 5.3±1.2% (n=6, non-decay-corrected) overall radiochemical yield with radiochemical purity >99% and specific activity of 35-116GBq/μmol. Usually, 2.95±0.65GBq (n=6, EOS) patient ready dose was produced from about 55.5GBq [(11)C]CO2 in 50min.
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22
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Escherichia coli Nissle 1917 enhances bioavailability of serotonin in gut tissues through modulation of synthesis and clearance. Sci Rep 2015; 5:17324. [PMID: 26616662 PMCID: PMC4663480 DOI: 10.1038/srep17324] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/12/2015] [Indexed: 12/15/2022] Open
Abstract
Accumulating evidence shows indigenous gut microbes can interact with the human host through modulation of serotonin (5-HT) signaling. Here we investigate the impact of the probiotic Escherichia coli Nissle 1917 (EcN) on 5-HT signalling in gut tissues. Ex-vivo mouse ileal tissue sections were treated with either EcN or the human gut commensal MG1655, and effects on levels of 5-HT, precursors, and metabolites, were evaluated using amperometry and high performance liquid chromatography with electrochemical detection (HPLC-EC). Exposure of tissue to EcN cells, but not MG1655 cells, was found to increase levels of extra-cellular 5-HT. These effects were not observed when tissues were treated with cell-free supernatant from bacterial cultures. In contrast, when supernatant recovered from untreated ileal tissue was pre-incubated with EcN, the derivative cell-free supernatant was able to elevate 5-HT overflow when used to treat fresh ileal tissue. Measurement of 5-HT precursors and metabolites indicated EcN also increases intracellular 5-HTP and reduces 5-HIAA. The former pointed to modulation of tryptophan hydroxylase-1 to enhance 5-HT synthesis, while the latter indicates an impact on clearance into enterocytes through SERT. Taken together, these findings show EcN is able to enhance 5-HT bioavailability in ileal tissues through interaction with compounds secreted from host tissues.
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23
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Kamson DO, Lee TJ, Varadarajan K, Robinette NL, Muzik O, Chakraborty PK, Snyder M, Barger GR, Mittal S, Juhász C. Clinical significance of tryptophan metabolism in the nontumoral hemisphere in patients with malignant glioma. J Nucl Med 2014; 55:1605-10. [PMID: 25189339 DOI: 10.2967/jnumed.114.141002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED α-(11)C-methyl-L-tryptophan (AMT) PET allows evaluation of brain serotonin synthesis and can also track upregulation of the immunosuppressive kynurenine pathway in tumor tissue. Increased AMT uptake is a hallmark of World Health Organization grade III-IV gliomas. Our recent study also suggested decreased frontal cortical AMT uptake in glioma patients contralateral to the tumor. The clinical significance of extratumoral tryptophan metabolism has not been established. In the present study, we investigated clinical correlates of tryptophan metabolic abnormalities in the nontumoral hemisphere of glioma patients. METHODS Standardized AMT uptake values (SUVs) and the uptake rate constant of AMT (K [mL/g/min], a measure proportional to serotonin synthesis in nontumoral gray matter) were quantified in the frontal and temporal cortex and thalamus in the nontumoral hemisphere in 77 AMT PET scans of 66 patients (41 men, 25 women; mean age ± SD, 55 ± 15 y) with grade III-IV gliomas. These AMT values were determined before treatment in 35 and after treatment in 42 patients and were correlated with clinical variables and survival. RESULTS AMT uptake in the thalamus showed a moderate age-related increase before treatment (SUV, r = 0.39, P = 0.02) but decrease after treatment (K, r = -0.33, P = 0.057). Women had higher thalamic SUVs before treatment (P = 0.037) and higher thalamic (P = 0.013) and frontal cortical K values (P = 0.023) after treatment. In the posttreatment glioma group, high thalamic SUVs and high thalamocortical SUV ratios were associated with short survival in Cox regression analysis. The thalamocortical ratio remained strongly prognostic (P < 0.01) when clinical predictors, including age, glioma grade, and time since radiotherapy, were entered in the regression model. Long interval between radiotherapy and posttreatment AMT PET as well as high radiation dose affecting the thalamus were associated with lower contralateral thalamic or cortical AMT uptake values. CONCLUSION These observations provide evidence for altered tryptophan uptake in contralateral cortical and thalamic brain regions in glioma patients after initial therapy, suggesting treatment effects on the serotonergic system. Low thalamic tryptophan uptake appears to be a strong, independent predictor of long survival in patients with previous glioma treatment.
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Affiliation(s)
- David O Kamson
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan Department of Pediatrics, Wayne State University, Detroit, Michigan
| | - Tiffany J Lee
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan
| | - Kaushik Varadarajan
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan
| | - Natasha L Robinette
- Department of Radiology, Wayne State University, Detroit, Michigan Karmanos Cancer Institute, Detroit, Michigan
| | - Otto Muzik
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan Department of Pediatrics, Wayne State University, Detroit, Michigan Department of Radiology, Wayne State University, Detroit, Michigan Department of Neurology, Wayne State University, Detroit, Michigan
| | - Pulak K Chakraborty
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan Department of Radiology, Wayne State University, Detroit, Michigan
| | | | - Geoffrey R Barger
- Karmanos Cancer Institute, Detroit, Michigan Department of Neurology, Wayne State University, Detroit, Michigan
| | - Sandeep Mittal
- Karmanos Cancer Institute, Detroit, Michigan Department of Neurosurgery, Wayne State University, Detroit, Michigan; and Department of Oncology, Wayne State University, Detroit, Michigan
| | - Csaba Juhász
- PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, Michigan Department of Pediatrics, Wayne State University, Detroit, Michigan Karmanos Cancer Institute, Detroit, Michigan Department of Neurology, Wayne State University, Detroit, Michigan
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24
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Booij L, Soucy JP, Young SN, Regoli M, Gravel P, Diksic M, Leyton M, Pihl RO, Benkelfat C. Brain serotonin synthesis in MDMA (ecstasy) polydrug users: an alpha-[11
C]methyl-l
-tryptophan study. J Neurochem 2014; 131:634-44. [DOI: 10.1111/jnc.12826] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 06/30/2014] [Accepted: 07/14/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Linda Booij
- Department of Psychology; Queen's University; Kingston Ontario Canada
- Department of Psychiatry; McGill University; Montreal Quebec Canada
- Sainte-Justine Hospital Research Center; University of Montreal; Montreal Quebec Canada
| | - Jean-Paul Soucy
- McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
| | - Simon N. Young
- Department of Psychiatry; McGill University; Montreal Quebec Canada
| | - Martine Regoli
- Department of Psychiatry; McGill University; Montreal Quebec Canada
| | - Paul Gravel
- Department of Psychiatry; McGill University; Montreal Quebec Canada
| | - Mirko Diksic
- McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
- Department of Neurology and Neurosurgery; McGill University; Montreal Quebec Canada
| | - Marco Leyton
- Department of Psychiatry; McGill University; Montreal Quebec Canada
- McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
- Department of Neurology and Neurosurgery; McGill University; Montreal Quebec Canada
- Department of Psychology; McGill University; Montreal Quebec Canada
| | - Robert O. Pihl
- Department of Psychiatry; McGill University; Montreal Quebec Canada
- Department of Psychology; McGill University; Montreal Quebec Canada
| | - Chawki Benkelfat
- Department of Psychiatry; McGill University; Montreal Quebec Canada
- McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
- Department of Neurology and Neurosurgery; McGill University; Montreal Quebec Canada
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25
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Visser AKD, Ramakrishnan NK, Willemsen ATM, Di Gialleonardo V, de Vries EFJ, Kema IP, Dierckx RAJO, van Waarde A. [(11)C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain. J Cereb Blood Flow Metab 2014; 34:118-25. [PMID: 24084697 PMCID: PMC3887351 DOI: 10.1038/jcbfm.2013.171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 08/08/2013] [Accepted: 09/02/2013] [Indexed: 11/09/2022]
Abstract
The PET tracer [(11)C]5-hydroxytryptophan ([(11)C]5-HTP), which is converted to [(11)C]5-hydroxytryptamine ([(11)C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [(11)C]5-HTP in rat? Male rats were scanned with [(11)C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [(11)C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [(11)C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [(11)C]5-HTP to [(11)C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [(11)C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.
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Affiliation(s)
- Anniek K D Visser
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nisha K Ramakrishnan
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Antoon T M Willemsen
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Valentina Di Gialleonardo
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ido P Kema
- Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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26
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Young SN. Elevated incidence of suicide in people living at altitude, smokers and patients with chronic obstructive pulmonary disease and asthma: possible role of hypoxia causing decreased serotonin synthesis. J Psychiatry Neurosci 2013; 38:423-6. [PMID: 24148847 PMCID: PMC3819157 DOI: 10.1503/jpn.130002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recent research indicates that suicide rates are elevated in those living at higher altitudes in both the United States and South Korea. A possible mechanism that was proposed is metabolic stress associated with hypoxia. This commentary discusses these results, and also the association between elevated suicide rates and other conditions associated with hypoxia (smoking, chronic obstructive pulmonary disease and asthma). Tryptophan hydroxylase may not normally be saturated with oxygen, so mild hypoxia would decrease serotonin synthesis. Low brain serotonin is known to be associated with suicide. Thus, the commentary proposes and discusses the hypothesis that decreased brain serotonin synthesis associated with hypoxia is a mechanism that may contribute to suicide in conditions causing hypoxia. Finally the commentary proposes various studies that could test aspects of this hypothesis.
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Affiliation(s)
- Simon N. Young
- Correspondence to: S.N. Young, Department of Psychiatry, McGill University, 1033 Pine Ave. W, Montréal QC H3A 1A1;
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27
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Sakai Y, Nishikawa M, Diksic M, Aubé M. α-[11C] methyl-L tryptophan-PET as a surrogate for interictal cerebral serotonin synthesis in migraine without aura. Cephalalgia 2013; 34:165-73. [DOI: 10.1177/0333102413506126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Alteration in central serotonin biology has been implicated in migraine, and serotonin (5-HT) agonists have been available for more than a decade in the treatment of that condition. Objectives To test this hypothesis, we studied in vivo using positron-emission tomography (PET) and α-[11C] methyl-L-tryptophan (α-[11C]MTrp) as a surrogate marker of cerebral 5-HT synthetic rate before and after administration of eletriptan in migraine and control subjects. Methods Six nonmenopausal female migraine subjects with migraine without aura (MoA) and six nonmenopausal age-matched female control subjects were scanned at baseline and after oral administration of 40 mg of eletriptan. Migraine subjects at the time of PET had to have been headache free for a minimum of three days. Images of (α-[11C]MTrp) brain trapping were colocalized with individual MRI images in three dimensions and analyzed. Results There was no difference in baseline cerebral global 5-HT synthesis between migraine and control subjects. After administration of eletriptan, there was a striking global reduction in cerebral 5-HT synthesis (K*) in the migraine group and in 22 regions of interest (ROIs). In control subjects, no significant changes were found in global cerebral 5-HT synthesis (K*) or in any of the ROIs. Conclusions These findings suggest in migraine an interictal alteration in the regulation mechanisms of cerebral 5-HT synthesis.
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Affiliation(s)
- Y Sakai
- Montreal Neurological Institute, and Department of Neurology and Neurosurgery, McGill University, Canada
- Present address: Department of Neuropsychiatry, Fukushima Medical University School of Medicine, Japan
| | - M Nishikawa
- Montreal Neurological Institute, and Department of Neurology and Neurosurgery, McGill University, Canada
- Present address: Department of Social Education, Kawamura Gakuen Woman's University, Japan
| | - M Diksic
- Montreal Neurological Institute, and Department of Neurology and Neurosurgery, McGill University, Canada
| | - M Aubé
- Montreal Neurological Institute, and Department of Neurology and Neurosurgery, McGill University, Canada
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28
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Behavioral effects of alpha-alkylated amino acid analogs in the C57BL/6J mouse. Behav Brain Res 2013; 252:432-8. [PMID: 23756141 DOI: 10.1016/j.bbr.2013.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 11/24/2022]
Abstract
Although a series of amino acid analogs have been shown to modulate brain function, information on the pharmacology of alpha-alkylated amino acids (AAAA) is limited. In particular there is no information on the effect of these amino acid analogs (AAA) on the elevated plus maze, the tail suspension test and the forced swim test. It was therefore the aim of the study to test a series of AAAA in these paradigms in order to explore behavioral activities of this compound class. 10 male mice per group aged between 10 and 14 weeks were used. Vehicle-treated controls were used in addition to intraperitoneal injections of 1, 10 and 100mg/kg body weight of each, alpha-amino-isobutyic acid (AIB), isovaline (IVA), alpha-propyl-alanine (APA), alpha-butyl-alanine (ABA), alpha-pentyl-alanine (APnA), alpha-ethylphenylglycine (AEPG) and alpha-methyl-valine (AMV). The elevated plus maze (EPM), the tail suspension test (TST) and forced swim test (FST) were used for behavioral testing. There were dose-dependent results: all compounds increased time and pathlength in the open arm of the EPM at least at one dose administered. In the TST and in the FST only the 100mg dose was showing an effect. The results show pharmacological activity modifying the EPM in low doses suggesting the use in treatment of behavioral traits and symptoms represented by or linked to the EPM including anxiety-related behavior including depression. Compounds acting at higher doses may be used to induce behavioral changes and thus serve as neurobiological-neuropharmacological tools.
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29
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Skelin I, Fikre-Merid M, Diksic M. Both acute and subchronic treatments with pindolol, a 5-HT1A and β1 and β2 adrenoceptor antagonist, elevate regional serotonin synthesis in the rat brain: An autoradiographic study. Neurochem Int 2012; 61:1417-23. [DOI: 10.1016/j.neuint.2012.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 09/24/2012] [Accepted: 10/12/2012] [Indexed: 10/27/2022]
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30
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Booij L, Turecki G, Leyton M, Gravel P, Lopez De Lara C, Diksic M, Benkelfat C. Tryptophan hydroxylase(2) gene polymorphisms predict brain serotonin synthesis in the orbitofrontal cortex in humans. Mol Psychiatry 2012; 17:809-17. [PMID: 21747395 DOI: 10.1038/mp.2011.79] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Brain regional serotonin synthesis can be estimated in vivo using positron emission tomography (PET) and α-[((11))C]methyl-L-tryptophan ((11)C-AMT) trapping (K*) as a proxy. Recently, we reported evidence of lower normalized (11)C-AMT trapping in the orbitofrontal cortex (OBFC) of subjects meeting the criteria for an impulsive and/or aggressive behavioral phenotype. In this study, we examined whether part of the variance in OBFC serotonin synthesis is related to polymorphisms of the gene that encodes for the indoleamine's rate-limiting enzyme in the brain, tryptophan hydroxylase-2 (TPH(2)). In all, 46 healthy controls had PET (11)C-AMT scans and were genotyped for 11 single-nucleotide polymorphisms (SNPs) distributed across the TPH(2) gene and its 5' upstream region. Several TPH(2) SNPs were associated with lower normalized blood-to-brain clearance of (11)C-AMT in the OBFC. Dose-effect relationships were found for two variants (rs6582071 and rs4641527, respectively, located in the 5' upstream region and intron 1) that have previously been associated with suicide. Associations in the OBFC remained statistically significant in a mixed larger sample of patients and controls. These results suggest that in humans, genetic factors might partly account for variations in serotonin synthesis in the OBFC.
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Affiliation(s)
- L Booij
- Department of Psychiatry, McGill University, Montreal, QC, Canada
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31
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Booij L, Benkelfat C, Leyton M, Vitaro F, Gravel P, Lévesque ML, Arseneault L, Diksic M, Tremblay RE. Perinatal effects on in vivo measures of human brain serotonin synthesis in adulthood: a 27-year longitudinal study. Eur Neuropsychopharmacol 2012; 22:419-23. [PMID: 22257439 DOI: 10.1016/j.euroneuro.2011.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/28/2011] [Accepted: 11/14/2011] [Indexed: 11/30/2022]
Abstract
There is an increasing evidence that prenatal and early postnatal stressors have life long impacts on physical and mental health problems. Animal studies have shown that this could include enduring changes to brain serotonin neurotransmission. In the present study, we tested whether perinatal adversity in humans has a long-term impact on brain serotonin neurotransmission in adulthood. Twenty-six healthy males, recruited from a 27-year longitudinal study, underwent a positron emission tomography scan with the tracer alpha-[¹¹C]methyl-L-tryptophan (¹¹C-AMT), as an index of serotonin synthesis capacity. The trapping constant is taken as a proxy for the regional 5-HT synthesis. Birth complications, especially a delivery where the fetus showed signs of physiological distress, predicted lower ¹¹C-AMT trapping in the hippocampus and medial orbitofrontal cortex. Lower ¹¹C-AMT trapping in the medial orbitofrontal cortex was also predicted by maternal smoking and lower birth weight. There were no effects of childhood or recent adversity. This is the first human study reporting associations between perinatal adversity and adult ¹¹C-AMT trapping in the hippocampus and medial orbitofrontal cortex. The associations suggest that limbic serotonin pathways may be particularly vulnerable to environmental challenges during the period when they undergo the most prominent neurodevelopmental changes. In combination with other risk factors, perinatal stressors may contribute to increased vulnerability for psychiatric disorders in which serotonin plays a major role.
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Affiliation(s)
- Linda Booij
- Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada.
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32
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Skelin I, Kovačević T, Sato H, Diksic M. The opposite effect of a 5-HT1B receptor agonist on 5-HT synthesis, as well as its resistant counterpart, in an animal model of depression. Brain Res Bull 2012; 88:477-86. [PMID: 22542420 DOI: 10.1016/j.brainresbull.2012.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 01/29/2023]
Abstract
Flinders Sensitive Line (FSL) rat is as an animal model of depression with altered parameters of the serotonergic (5-HT) system function (5-HT synthesis rates, tissue concentrations, release, receptor density and affinity), as well as an altered sensitivity of these parameters to different 5-HT based antidepressants. The effects of acute and chronic treatments with the 5-HT(1B) agonist, CP-94253 on 5-HT synthesis, in the FSL rats and the Flinders Resistant Line (FRL) controls were measured using α-[(14)C]methyl-L-tryptophan (α-MTrp) autoradiography. CP-94253 (5mg/kg), or an adequate volume of saline, was injected i.p. as a single dose in the acute experiment or delivered via the subcutaneously implanted osmotic minipump (5 mg/kg/day for 14 days) in the chronic experiment. The acute treatment with CP-94253 significantly decreased the 5-HT synthesis in both the FRL and FSL rats, with a more widespread effect in the FRL rats. Chronic treatment with CP-94253 significantly decreased 5-HT synthesis in the FRL rats, while 5-HT synthesis in the FSL rats was significantly increased throughout the brain. In both the acute and chronic experiment, the FRL rats had higher brain 5-HT synthesis rates, relative to the FSL rats. The shift in the direction of the treatment effect from acute to chronic, using the 5-HT(1B) agonist, CP-94253, on 5-HT synthesis in the FSL model of depression, with an opposite effect on the control FRL rats, suggests the differential adaptation of the 5-HT system in the FSL and FRL rats to chronic stimulation of 5-HT(1B) receptors.
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Affiliation(s)
- Ivan Skelin
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, and Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Que., Canada H3A 2B4
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Hasegawa S, Fikre-Merid M, Diksic M. 5-HT2A receptor antagonist M100907 reduces serotonin synthesis: an autoradiographic study. Brain Res Bull 2012; 87:44-9. [PMID: 22056993 PMCID: PMC3653840 DOI: 10.1016/j.brainresbull.2011.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 10/19/2011] [Indexed: 11/16/2022]
Abstract
The effects of the administration of the serotonin (5-HT)(2A) antagonist, M100907, on 5-HT synthesis rates, were evaluated using the α-[(14)C]methyl-l-tryptophan (α-MTrp) autoradiographic method. In the treatment study, M100907 (10mg/kg) was injected intraperitoneally 30 min before the α-MTrp injection (30 μCi over 2 min). A single dose of M100907 caused a significant decrease in the synthesis in the anterior olfactory nucleus, accumbens nucleus, frontal cortex, sensory-motor cortex, cingulate cortex, medial caudate-putamen, dorsal thalamus, substantia nigra, inferior collicus, raphe magnus nucleus, superior olive, and raphe pallidus nucleus. These data suggest that the terminal 5-HT(2A) receptors are involved in the regulation of 5-HT synthesis in the entire brain. Further, 5-HT synthesis is likely regulated by the 5-HT(2A) antagonistic property of M100907 in the cortices, anterior olfactory nucleus, caudate putamen, and nucleus accumbens.
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Affiliation(s)
| | - Maraki Fikre-Merid
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Mirko Diksic
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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35
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Responses of growth performance and tryptophan metabolism to oxidative stress induced by diquat in weaned pigs. Animal 2012; 6:928-34. [DOI: 10.1017/s1751731111002382] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Alkonyi B, Mittal S, Zitron I, Chugani DC, Kupsky WJ, Muzik O, Chugani HT, Sood S, Juhász C. Increased tryptophan transport in epileptogenic dysembryoplastic neuroepithelial tumors. J Neurooncol 2011; 107:365-72. [PMID: 22048879 DOI: 10.1007/s11060-011-0750-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/24/2011] [Indexed: 12/26/2022]
Abstract
Dysembryoplastic neuroepithelial tumors (DNTs) are typically hypometabolic but can show increased amino acid uptake on positron emission tomography (PET). To better understand mechanisms of amino acid accumulation in epileptogenic DNTs, we combined quantitative α-[(11)C]methyl-L: -tryptophan (AMT) PET with tumor immunohistochemistry. Standardized uptake values (SUVs) of AMT and glucose were measured in 11 children with temporal lobe DNT. Additional quantification for AMT transport and metabolism was performed in 9 DNTs. Tumor specimens were immunostained for the L: -type amino acid transporter 1 (LAT1) and indoleamine 2,3-dioxygenase (IDO), a key enzyme of the immunomodulatory kynurenine pathway. All 11 tumors showed glucose hypometabolism, while mean AMT SUVs were higher than normal cortex in eight DNTs. Further quantification showed increased AMT transport in seven and high AMT metabolic rates in three DNTs. Two patients showing extratumoral cortical increases of AMT SUV had persistent seizures despite complete tumor resection. Resected DNTs showed moderate to strong LAT1 and mild to moderate IDO immunoreactivity, with the strongest expression in tumor vessels. These results indicate that accumulation of tryptophan in DNTs is driven by high amino acid transport, mediated by LAT1, which can provide the substrate for tumoral tryptophan metabolism through the kynurenine pathway, that can produce epileptogenic metabolites. Increased AMT uptake can extend to extratumoral cortex, and presence of such cortical regions may increase the likelihood of recurrent seizures following surgical excision of DNTs.
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Affiliation(s)
- Bálint Alkonyi
- PET Center, Children's Hospital of Michigan, 3901 Beaubien Blvd, Detroit, MI 48201, USA
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Paterson LM, Kornum BR, Nutt DJ, Pike VW, Knudsen GM. 5-HT radioligands for human brain imaging with PET and SPECT. Med Res Rev 2011; 33:54-111. [PMID: 21674551 DOI: 10.1002/med.20245] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT(1A), 5-HT(1B), 5-HT(2A), and 5-HT(4) receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging.
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Affiliation(s)
- Louise M Paterson
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, Burlington Danes Building, Du Cane Road, London, United Kingdom
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Acute desipramine treatment reduces regional serotonin synthesis rates, while chronic treatment elevates rates, in a rat model of depression: An autoradiographic study. Neurochem Int 2011; 58:759-66. [DOI: 10.1016/j.neuint.2011.02.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/15/2011] [Accepted: 02/25/2011] [Indexed: 11/18/2022]
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The lumped constant of α-methyl-l-tryptophan is not influenced by drugs acting through serotonergic system. Neurochem Int 2011; 58:826-32. [PMID: 21414366 DOI: 10.1016/j.neuint.2011.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 03/08/2011] [Indexed: 11/24/2022]
Abstract
Lumped constant (LC) is a constant used to convert brain trapping constant of α-methyl-l-tryptophan (using α-(14)C-methyl-l-tryptophan) into the constant for conversion of tryptophan into serotonin (5-hydroxytryptamine, 5-HT), which can be then used with certain assumptions in the calculation of the brain regional 5-HT synthesis rate. The aim of the present study was to investigate the acute effects of two drugs on the regional stability of the LC and possible effect on its value. Drugs used were a selective 5-HT reuptake inhibitor, fluoxetine, and a drug that releases 5-HT and inhibits 5-HT uptake, d,l-fenfluramine. The values of the LC from those experiments were compared with the value of LC obtained in the saline treated rats. KT is the constant for tryptophan conversion into 5-HT, which was measured by an autoradiographic method in more than twenty brain regions, using labelled tryptophan ((14)C-Trp) as tracer, after the fraction incorporated into proteins was removed. The trapping constant K(α) for α-methyl-l-tryptophan was also measured autoradiographically in a separate group of rats. All measurements were done in drug and saline (control) treated rats. The regional LC constants were calculated as the ratios between KT and K(α). Statistical evaluation showed that the regional values in each of these three sets were normally distributed, and that the three sets of LC values calculated as the mean of logarithmic differences (saline 0.450 ± 0.055; fluoxetine 0.429 ± 0.091; d,l-fenfluramine 0.48 ± 0.09) did not differ significantly. The overall weighted mean value of the LC from all three sets of measurements was 0.452 ± 0.041, and this value was not significantly different from the LC value of 0.42 ± 0.07, i.e. value obtained in our previous studies. These results showed the unaltered LC value in discrete rat brain regions after treatment with fluoxetine or d,l-fenfluramine, and confirmed that the numerical value of the LC used in our previous studies was not altered by treatment with drugs affecting 5-HT transmission and 5-HT synthesis rate.
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Berney A, Leyton M, Gravel P, Sibon I, Sookman D, Rosa Neto P, Diksic M, Nakai A, Pinard G, Todorov C, Okazawa H, Blier P, Nordahl TE, Benkelfat C. Brain regional α-[11C]methyl-L-tryptophan trapping in medication-free patients with obsessive-compulsive disorder. ACTA ACUST UNITED AC 2011; 68:732-41. [PMID: 21383250 DOI: 10.1001/archgenpsychiatry.2011.16] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT The hypothesis of a serotonin (5-hydroxytryptamine [5-HT]) dysfunction in obsessive-compulsive disorder (OCD) stems largely from the clinical efficacy of 5-HT reuptake inhibitors. Serotonergic abnormalities in the unmedicated symptomatic state, however, remain to be fully characterized. OBJECTIVE To investigate brain regional 5-HT synthesis, as indexed by positron emission tomography and the α-[(11)C]methyl-L-tryptophan trapping constant (K*), in treatment-free adults meeting criteria for OCD. DESIGN Between-group comparison. SETTING Department of Psychiatry and Montreal Neurological Institute, McGill University, and Department of Psychology, McGill University Health Centre, Quebec, Canada. PARTICIPANTS Twenty-one medication-free patients with OCD (15 men with a mean [SD] age of 33.2 [9.3] years and 6 women with a mean [SD] age of 35.8 [7.1] years) and 21 healthy controls matched for age and sex (15 men with a mean [SD] age of 32.9 [10.1] years and 6 women with a mean [SD] age of 36.5.5 [8.6] years). Main Outcome Measure The α-[(11)C]methyl-L-tryptophan brain trapping constant K*, which was analyzed with Statistical Parametric Mapping (SPM8) and with proportional normalization (extent threshold of 100 voxels with a peak threshold of P ≤ .005). RESULTS Compared with healthy controls, the patients with OCD exhibited significantly greater α-[(11)C]methyl-L-tryptophan trapping in the right hippocampus and left temporal gyrus (Brodmann area 20). In the larger subsample of all men, these same differences were also evident, as well as higher K* values in the caudate nucleus. Individual differences in symptom severity correlated positively with K* values sampled from the caudate and temporal lobe of the patients with OCD, respectively. There were no regions where the patients exhibited abnormally low K* values. Volumetric analyses found no morphometric alterations that would account for the group differences. CONCLUSION The results support previous reports of greater striatal and temporal lobe activity in patients with OCD than in healthy controls and suggest that these disturbances include a serotonergic component. Previously reported glucose metabolic disturbances in OCD involving the orbitofrontal and cingulate cortices, in comparison, might reflect postsynaptic changes in the serotonergic system.
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Affiliation(s)
- Alexandre Berney
- DERBH, Department of Psychiatry, McGill University, 1033 Pine Ave West, Montreal, QC H3A 1A1, Canada
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Simultaneous determination of tryptophan, kynurenine and 5-hydroxytryptamine by HPLC: Application in uremic patients undergoing hemodialysis. Clin Biochem 2011; 44:226-30. [DOI: 10.1016/j.clinbiochem.2010.10.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 10/17/2010] [Accepted: 10/20/2010] [Indexed: 02/04/2023]
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Takano H, Ito H, Takahashi H, Arakawa R, Okumura M, Kodaka F, Otsuka T, Kato M, Suhara T. Serotonergic neurotransmission in the living human brain: A positron emission tomography study using [11C]dasb and [11C]WAY100635 in young healthy men. Synapse 2011; 65:624-33. [DOI: 10.1002/syn.20883] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 11/10/2010] [Indexed: 12/21/2022]
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Measuring serotonin synthesis: from conventional methods to PET tracers and their (pre)clinical implications. Eur J Nucl Med Mol Imaging 2010; 38:576-91. [PMID: 21113591 PMCID: PMC3034914 DOI: 10.1007/s00259-010-1663-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 11/01/2010] [Indexed: 12/20/2022]
Abstract
The serotonergic system of the brain is complex, with an extensive innervation pattern covering all brain regions and endowed with at least 15 different receptors (each with their particular distribution patterns), specific reuptake mechanisms and synthetic processes. Many aspects of the functioning of the serotonergic system are still unclear, partially because of the difficulty of measuring physiological processes in the living brain. In this review we give an overview of the conventional methods of measuring serotonin synthesis and methods using positron emission tomography (PET) tracers, more specifically with respect to serotonergic function in affective disorders. Conventional methods are invasive and do not directly measure synthesis rates. Although they may give insight into turnover rates, a more direct measurement may be preferred. PET is a noninvasive technique which can trace metabolic processes, like serotonin synthesis. Tracers developed for this purpose are α-[11C]methyltryptophan ([11C]AMT) and 5-hydroxy-L-[β-11C]tryptophan ([11C]5-HTP). Both tracers have advantages and disadvantages. [11C]AMT can enter the kynurenine pathway under inflammatory conditions (and thus provide a false signal), but this tracer has been used in many studies leading to novel insights regarding antidepressant action. [11C]5-HTP is difficult to produce, but trapping of this compound may better represent serotonin synthesis. AMT and 5-HTP kinetics are differently affected by tryptophan depletion and changes of mood. This may indicate that both tracers are associated with different enzymatic processes. In conclusion, PET with radiolabelled substrates for the serotonergic pathway is the only direct way to detect changes of serotonin synthesis in the living brain.
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Frey BN, Skelin I, Sakai Y, Nishikawa M, Diksic M. Gender differences in alpha-[(11)C]MTrp brain trapping, an index of serotonin synthesis, in medication-free individuals with major depressive disorder: a positron emission tomography study. Psychiatry Res 2010; 183:157-66. [PMID: 20630715 DOI: 10.1016/j.pscychresns.2010.05.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 02/12/2010] [Accepted: 05/13/2010] [Indexed: 12/27/2022]
Abstract
Women are at higher risk than men for developing major depressive disorder (MDD), but the mechanisms underlying this higher risk are unknown. Here, we report proportionally normalized alpha-[(11)C]methyl-L-tryptophan brain trapping constant (alpha-[(11)C]MTrp K*(N)), an index of serotonin synthesis, in 25 medication-free individuals with MDD and in 25 gender- and age-matched healthy subjects who were studied using positron emission tomography (PET). Comparisons of alpha-[(11)C]MTrp K*(N) values between the men and women were conducted at the voxel and cluster levels using Statistical Parametric Mapping 2 (SPM2) analysis. In addition, the alpha-[(11)C]MTrp K*(N) values on both sides of the brain were extracted and compared to identify the left to right differences, as well as the gender differences. Women with MDD displayed higher alpha-[(11)C]MTrp K*(N) than men in the inferior frontal gyrus, anterior cingulate cortex (ACC), parahippocampal gyrus, precuneus, superior parietal lobule, and occipital lingual gyrus. In a matched group of normal subjects the gender differences were opposite from those found in MDD patients. Significant hemispheric differences in fronto-limbic structures between men and women with MDD were also observed. The K*(N) extracted from the volumes identified in MDD patients and in male and female normal subjects suggested no significant differences between males and females. In conclusion, depressed women have higher serotonin synthesis in multiple regions of the prefrontal cortex and limbic system involved with mood regulation, as compared with depressed men. Gender differences in brain serotonin synthesis may be related to higher risk for MDD in women.
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Affiliation(s)
- Benicio N Frey
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada H3A 2B4
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Booij L, Tremblay RE, Leyton M, Séguin JR, Vitaro F, Gravel P, Perreau-Linck E, Lévesque ML, Durand F, Diksic M, Turecki G, Benkelfat C. Brain serotonin synthesis in adult males characterized by physical aggression during childhood: a 21-year longitudinal study. PLoS One 2010; 5:e11255. [PMID: 20582306 PMCID: PMC2889822 DOI: 10.1371/journal.pone.0011255] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 05/26/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Adults exhibiting severe impulsive and aggressive behaviors have multiple indices of low serotonin (5-HT) neurotransmission. It remains unclear though whether low 5-HT mediates the behavior or instead reflects a pre-existing vulnerability trait. METHODOLOGY/PRINCIPAL FINDINGS In the present study, positron emission tomography with the tracer alpha-[(11)C]methyl-L-tryptophan ((11)C-AMT) was used to compare 5-HT synthesis capacity in two groups of adult males from a 21-year longitudinal study (mean age +/- SD: 27.1+/-0.7): individuals with a history of childhood-limited high physical aggression (C-LHPA; N = 8) and individuals with normal (low) patterns of physical aggression (LPA; N = 18). The C-LHPA males had significantly lower trapping of (11)C-AMT bilaterally in the orbitofrontal cortex and self-reported more impulsiveness. Despite this, in adulthood there were no group differences in plasma tryptophan levels, genotyping, aggression, emotional intelligence, working memory, computerized measures of impulsivity, psychosocial functioning/adjustment, and personal and family history of mood and substance abuse disorders. CONCLUSIONS/SIGNIFICANCE These results force a re-examination of the low 5-HT hypothesis as central in the biology of violence. They suggest that low 5-HT does not mediate current behavior and should be considered a vulnerability factor for impulsive-aggressive behavior that may or may not be expressed depending on other biological factors, experience, and environmental support during development.
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Affiliation(s)
- Linda Booij
- Department of Psychiatry, McGill University, Montreal, Canada
| | - Richard E. Tremblay
- Departments of Psychology and Pediatrics, University of Montreal, Montreal, Canada
- School of Public Health and Population Sciences, University College, Dublin, Ireland
- INSERM U669, Paris, France
- Sainte-Justine Hospital Research Center, Montreal, Canada
- Department of Psychiatry, University of Montreal, Montreal, Canada
| | - Marco Leyton
- Department of Psychiatry, McGill University, Montreal, Canada
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Jean R. Séguin
- Sainte-Justine Hospital Research Center, Montreal, Canada
- Department of Psychiatry, University of Montreal, Montreal, Canada
| | - Frank Vitaro
- Sainte-Justine Hospital Research Center, Montreal, Canada
- School of Psycho-Education, University of Montreal, Montreal, Canada
| | - Paul Gravel
- Department of Psychiatry, McGill University, Montreal, Canada
| | | | | | - France Durand
- Department of Psychiatry, McGill University, Montreal, Canada
| | - Mirko Diksic
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Hospital, McGill University, Montreal, Canada
| | - Chawki Benkelfat
- Department of Psychiatry, McGill University, Montreal, Canada
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada
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Frampton GA, Li H, Ramirez J, Mohamad A, DeMorrow S. Biogenic amines serotonin and dopamine regulate cholangiocyte hyperplastic and neoplastic growth. World J Gastrointest Pathophysiol 2010; 1:63-8. [PMID: 21607143 PMCID: PMC3097942 DOI: 10.4291/wjgp.v1.i2.63] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 03/26/2010] [Accepted: 04/02/2010] [Indexed: 02/06/2023] Open
Abstract
Biogenic amines, such as serotonin and dopamine, regulate a multitude of cellular responses. A great deal of effort has been invested into understanding the effects of these molecules and their corresponding receptor systems on cholangiocyte and cholangiocarcinoma secretion, apoptosis and growth. This review summarizes the results of these efforts and highlights the importance of these regulatory molecules on the physiology and pathophysiology of cholangiocytes. Specifically we have focused on the recent findings into the effects of serotonin and dopamine on cholangiocyte hyperplasia and neoplastic growth.
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Gravett N, Bhagwandin A, Fuxe K, Manger PR. Nuclear organization and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brain of the rock hyrax, Procavia capensis. J Chem Neuroanat 2009; 38:57-74. [DOI: 10.1016/j.jchemneu.2009.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 02/18/2009] [Accepted: 02/27/2009] [Indexed: 11/28/2022]
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Kanemaru K, Nishi K, Diksic M. AGN-2979, an inhibitor of tryptophan hydroxylase activation, does not affect serotonin synthesis in Flinders Sensitive Line rats, a rat model of depression, but produces a significant effect in Flinders Resistant Line rats. Neurochem Int 2009; 55:529-35. [PMID: 19463878 DOI: 10.1016/j.neuint.2009.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 04/25/2009] [Accepted: 05/10/2009] [Indexed: 10/20/2022]
Abstract
The neurotransmitter, serotonin, is involved in several brain functions, including both normal, physiological functions, and pathophysiological functions. Alterations in any of the normal parameters of serotonergic neurotransmission can produce several different psychiatric disorders, including major depression. In many instances, brain neurochemical variables are not able to be studied properly in humans, thus making the use of good animal models extremely valuable. One of these animal models is the Flinders Sensitive Line (FSL) of rats, which has face, predictive and constructive validities in relation to human depression. The objective of this study was to quantify the effect of the tryptophan hydroxylase (TPH) activation inhibitor, AGN-2979, on the FSL rats (rats with depression-like behaviour), and compare it to the effect on the Flinders Resistant Line (FRL) of rats used as the control rats. The effect was evaluated by measuring changes in regional serotonin synthesis in the vehicle treated rats (FSL-VEH and FRL-VEH) relative to those measured in the AGN-2979 treated rats (FSL-AGN and FRL-AGN). Regional serotonin synthesis was measured autoradiographically in more than 30 brain regions. The measurements were performed using alpha-[(14)C]methyl-l-tryptophan as the tracer. The results indicate that AGN-2979 did not produce a significant reduction of TPH activity in the AGN-2979 group relative to the vehicle group (a reduction would have been observed if there had been an activation of TPH by the experimental setup) in the FSL rats. On the other hand, there was a highly significant reduction of synthesis in the FRL rats treated by AGN-2979, relative to the vehicle group. Together, the results demonstrate that in the FSL rats, AGN-2979 does not affect serotonin synthesis. This suggests that there was no activation of TPH in the FSL rats during the experimental procedure, but such activation did occur in the FRL rats. Because of this finding, it could be hypothesized that TPH in the FSL rats cannot be easily activated. This may contribute to the development of depressive-like symptoms in the FSL rats ("depressed" rats), as they cannot easily modulate their need for elevated amounts of this neurotransmitter, and possibly other neurotransmitters. Further, because these rats represent a very good model of human depression, one can hypothesize that humans who do not have readily activated TPH may be more prone to develop depression.
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Affiliation(s)
- Kazuya Kanemaru
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Quebec, Canada
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Nishikawa M, Diksic M, Sakai Y, Kumano H, Charney D, Palacios-Boix J, Negrete J, Gill K. Alterations in Brain Serotonin Synthesis in Male Alcoholics Measured Using Positron Emission Tomography. Alcohol Clin Exp Res 2009; 33:233-9. [DOI: 10.1111/j.1530-0277.2008.00820.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Alpini G, Invernizzi P, Gaudio E, Venter J, Kopriva S, Bernuzzi F, Onori P, Franchitto A, Coufal M, Frampton G, Alvaro D, Lee SP, Marzioni M, Benedetti A, DeMorrow S. Serotonin metabolism is dysregulated in cholangiocarcinoma, which has implications for tumor growth. Cancer Res 2008; 68:9184-93. [PMID: 19010890 DOI: 10.1158/0008-5472.can-08-2133] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. Symptoms are usually evident after blockage of the bile duct by the tumor, and at this late stage, they are relatively resistant to chemotherapy and radiation therapy. Therefore, it is imperative that alternative treatment options are explored. We present novel data indicating that the metabolism of serotonin is dysregulated in cholangiocarcinoma cell lines, compared with normal cholangiocytes, and tissue and bile from cholangiocarcinoma patients. Specifically, there was an increased expression of tryptophan hydroxylase 1 and a suppression of monoamine oxidase A expression (enzymes responsible for the synthesis and degradation of serotonin, respectively) in cholangiocarcinoma. This resulted in an increased secretion of serotonin from cholangiocarcinoma and increased serotonin in the bile from cholangiocarcinoma patients. Increased local serotonin release may have implications on cholangiocarcinoma cell growth. Serotonin administration increased cholangiocarcinoma cell growth in vitro, whereas inhibition of serotonin synthesis decreases tumor cell growth both in vitro and in vivo. The data presented here represent the first evidence that serotonin metabolism is dysregulated in cholangiocarcinoma and that modulation of serotonin synthesis may represent an alternative target for the development of therapeutic strategies.
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Affiliation(s)
- Gianfranco Alpini
- Department of Medicine, Texas A&M Health Science Center, College of Medicine, Scott & White Hospital, Temple, TX 76504, USA
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