| 1. |
- Aarnio, Mikko, et al.
(author)
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Visualization of painful inflammation in patients with pain after traumatic ankle sprain using [(11)C]-D-deprenyl PET/CT.
- 2017
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In: Scandinavian Journal of Pain. - : Walter de Gruyter. - 1877-8860 .- 1877-8879. ; 17:1, s. 418-424
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Journal article (peer-reviewed)abstract
- BACKGROUND AND AIMS: Positron emission tomography (PET) with the radioligand [(11)C]-D-deprenyl has shown increased signal at location of pain in patients with rheumatoid arthritis and chronic whiplash injury. The binding site of [(11)C]-D-deprenyl in peripheral tissues is suggested to be mitochondrial monoamine oxidase in cells engaged in post-traumatic inflammation and tissue repair processes. The association between [(11)C]-D-deprenyl uptake and the transition from acute to chronic pain remain unknown. Further imaging studies of musculoskeletal pain at the molecular level would benefit from establishing a clinical model in a common and well-defined injury in otherwise healthy and drug-naïve subjects. The aim of this study was to investigate if [(11)C]-D-deprenyl uptake would be acutely elevated in unilateral ankle sprain and if tracer uptake would be reduced as a function of healing, and correlated with pain localizations and pain experience.METHODS: Eight otherwise healthy patients with unilateral ankle sprain were recruited at the emergency department. All underwent [(11)C]-D-deprenyl PET/CT in the acute phase, at one month and 6-14 months after injury.RESULTS: Acute [(11)C]-D-deprenyl uptake at the injury site was a factor of 10.7 (range 2.9-37.3) higher than the intact ankle. During healing, [(11)C]-D-deprenyl uptake decreased, but did not normalize until after 11 months. Patients experiencing persistent pain had prolonged [(11)C]-D-deprenyl uptake in painful locations.CONCLUSIONS AND IMPLICATIONS: The data provide further support that [(11)C]-D-deprenyl PET can visualize, quantify and follow processes in peripheral tissue that may relate to soft tissue injuries, inflammation and associated nociceptive signaling. Such an objective correlate would represent a progress in pain research, as well as in clinical pain diagnostics and management.
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| 2. |
- Appel, Lieuwe, et al.
(author)
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Altered NK1-receptor availability in patients with post traumatic stress disorder
- 2009
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In: [Biological Psychiatry 2009, 65(8), Suppl. 1, 118S, no. 394]. - : Elsevier BV. ; , s. 118S-
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Conference paper (peer-reviewed)abstract
- Background: Posttraumatic stress disorder (PTSD) is an anxiety disorder that can develop after one or more traumatic events causing extreme stress or grave physical harm. The neurokinin-1 (NK1) receptor is the primary receptor for substance P (SP); a neuropeptide suggested being involved in anxiety and depression. The present study investigated differences in NK1-receptor availability between PTSD patients and healthy controls, using positron emission tomography (PET). Methods: Eleven male refugee patients (age: 41±10) with DSM-IV defined PTSD and nine healthy male control subjects (age: 33±10) were investigated using the PET-tracer [11C]GR205171, supplied by Uppsala Imanet. GR205171 is a highly selective NK1-receptor antagonist. Scans were performed during 60 minutes in the resting state. Parametric images were generated using the graphical reference Patlak method assuming irreversible binding of [11C]GR205171 from 20-60 minutes and having cerebellum as reference region. Exploratory whole brain analyses were performed using the statistical parametric mapping (SPM2) software. Results: PTSD patients had lower [11C]GR205171 binding compared to controls, in frontal cortical clusters encompassing bilaterally insula and left Brodmann area 11, reflecting lower NK1-receptor availability. No areas were found in which PTSD patients had higher [11C]GR205171 binding. Conclusions: This is the first study reporting differences in NK1-receptor availability in PTSD patients relative to controls. A tentative conclusion is that PTSD patients have a down regulation of the NK1-receptor system, which could be either a risk factor or due to emotional trauma processing.
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| 3. |
- Appel, Lieuwe, et al.
(author)
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BL-1020, a novel antipsychotic candidate with GABA-enhancing effects : D2 receptor occupancy study in humans
- 2009
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In: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 19:12, s. 841-850
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Journal article (peer-reviewed)abstract
- BL-1020 is a potentially novel antipsychotic, which comprises the typical antipsychotic perphenazine linked by an ester bound to gamma-aminobutyric acid (GABA), intending a simultaneous dopamine-2 (D(2)) receptor blockade and GABA facilitation in the brain. This positron emission tomography (PET) study, using [(11)C]raclopride, assessed the extent and duration of D(2) receptor occupancy (D(2) RO) and safety for single doses of BL-1020 in healthy male subjects. Overall, this study did not raise any safety concern. Single doses of 16-32 mg BL-1020 caused a dose dependent striatal D(2) RO. The 32 mg dose of BL-1020 resulted in an average D(2) RO of 44% at 4-6 h post dosing (pd), which declined to 33% at 24 h pd. Equimolar doses of BL-1020 and perphenazine resulted in similar D(2) RO at 24 h pd. Pharmacokinetic-pharmacodynamic analysis predicted that oral once daily administration of 32 mg BL-1020 would result in D(2) ROs ranging from 52 to 66% at a steady state.
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| 4. |
- Appel, Lieuwe, et al.
(author)
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Tesofensine, a novel triple monoamine re-uptake inhibitor with anti-obesity effects : Dopamine transporter occupancy as measured by PET
- 2014
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In: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 24:2, s. 251-261
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Journal article (peer-reviewed)abstract
- Tesofensine (TE) is a novel triple monoannine re-uptake inhibitor inducing a potent inhibition of the re-uptake process in the synaptic cleft of the neurotransmitters dopamine, norepinephrine, and serotonin. In recent preclinical and clinical evaluations TE showed a robust anti-obesity effect, but the specific mechanism of this triple monoamine re-uptake inhibitor still needs to be further elucidated. This positron emission tomography (PET) study, using [C-11]beta CIT-FE, aimed to assess the degree of the dopamine transporter (DAT) occupancy, at constant TE plasma levels, following different oral, multiple doses of TE during totally 8-12 days. In addition, the relationships between DAT occupancy and TE plasma concentrations, or doses, were investigated to enable assessment of DAT occupancies in subsequent clinical trials. The results demonstrated that TE induced a dose-dependent blockade of DAT following multiple doses of 0.125-1 mg TE at anticipated steady-state conditions. The mean striatal DAT occupancy varied dose-dependently between 18% and 77%. A signnoid E-max model well described the relationship between striatal DAT occupancy and TE plasma concentrations or doses. It was estimated that the maximum achievable DAT occupancy was about 80% and that half of this effect was accomplished by approximately 0.25 mg TE and a plasma drug concentration of 4 ng/ml. The results indicated an important mechanism of action of TE on DAT. Further, these results suggest that the previously reported dose-dependent weight loss, in TE treated subjects, was in part mediated by an up-regulation of dopaminergic pathways due to enhanced amounts of synaptic dopamine after blockade of DAT.
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| 5. |
- Appel, Lieuwe, et al.
(author)
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Use of C-11-PE2I PET in Differential Diagnosis of Parkinsonian Disorders
- 2015
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In: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 56:2, s. 234-242
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Journal article (peer-reviewed)abstract
- In idiopathic Parkinson disease and atypical parkinsonian disorders, central dopaminergic and overall brain functional activity are altered to different degrees, causing difficulties in achieving an unambiguous clinical diagnosis. A dual examination using I-123-FP-CIT (I-123-N-omega-fluoropropyl- 2 beta-carbomethoxy-3 beta-(4-iodophenyl) nortropane, or I-123-ioflupane) SPECT and F-18-FDG PET provides complementary information on dopamine transporter (DAT) availability and overall brain functional activity, respectively. Parametric images based on a single, dynamic C-11-PE2I (N-(3-iodoprop-2E-enyl)-2 beta-carbomethoxy-3 beta-(4-methyl-phenyl) nortropane) scan potentially supply both DAT availability (nondisplaceable binding potential [BPND]) and relative cerebral blood flow (relative delivery [R-1]) at voxel level. This study aimed to evaluate the validity of C-11-PE2I PET against the dual-modality approach using I-123-FP-CIT SPECT and F-18-FDG PET.Methods: Sixteen patients with parkinsonian disorders had a dual examination with F-18-FDG PET and I-123-FP-CIT SPECT following clinical routines and additionally an experimental C-11-PE2I PET scan. Parametric BPND and R-1 images were generated using receptor parametric mapping with the cerebellum as a reference. T1-weighted MR imaging was used for automated definition of volumes of interest (VOI). The DAT VOIs included the basal ganglia, whereas the overall brain functional activity was examined using VOIs across the brain. BPND and R-1 values were compared with normalized I-123-FP-CIT and F-18-FDG uptake values, respectively, using Pearson correlations and regression analyses. In addition, 2 masked interpreters evaluated the images visually, in both the routine and the experimental datasets, for comparison of patient diagnoses.Results: Parametric C-11-PE2I BPND and R-1 images showed high consistency with I-123-FP-CIT SPECT and F-18-FDG PET images. Correlations between C-11-PE2I BPND and I-123-FP-CIT uptake ratios were 0.97 and 0.76 in the putamen and caudate nucleus, respectively. Regional C-11-PE2I R-1 values were moderately to highly correlated with normalized F-18-FDG values (range, 0.61-0.94). Visual assessment of DAT availability showed a high consistency between C-11-PE2I BPND and I-123-FP-CIT images, whereas the consistency was somewhat lower for appraisal of overall brain functional activity using I-123-FP-CIT and F-18-FDG images. Substantial differences were found between clinical diagnosis and both neuro-imaging diagnoses.Conclusion: A single, dynamic C-11-PE2I PET investigation is a powerful alternative to a dual examination with I-123-FP-CIT SPECT and F-18-FDG PET for differential diagnosis of parkinsonian disorders. A large-scale patient study is, however, needed to further investigate distinct pathologic patterns in overall brain functional activity for various parkinsonian disorders.
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| 6. |
- Bergman, Olle, 1978, et al.
(author)
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Association between amygdala reactivity and a dopamine transporter gene polymorphism.
- 2014
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In: Translational psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 4
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Journal article (peer-reviewed)abstract
- Essential for detection of relevant external stimuli and for fear processing, the amygdala is under modulatory influence of dopamine (DA). The DA transporter (DAT) is of fundamental importance for the regulation of DA transmission by mediating reuptake inactivation of extracellular DA. This study examined if a common functional variable number tandem repeat polymorphism in the 3' untranslated region of the DAT gene (SLC6A3) influences amygdala function during the processing of aversive emotional stimuli. Amygdala reactivity was examined by comparing regional cerebral blood flow, measured with positron emission tomography and [(15)O]water, during exposure to angry and neutral faces, respectively, in a Swedish sample comprising 32 patients with social anxiety disorder and 17 healthy volunteers. In a separate US sample, comprising 85 healthy volunteers studied with blood oxygen level-dependent functional magnetic resonance imaging, amygdala reactivity was assessed by comparing the activity during exposure to threatening faces and neutral geometric shapes, respectively. In both the Swedish and the US sample, 9-repeat carriers displayed higher amygdala reactivity than 10-repeat homozygotes. The results suggest that this polymorphism contributes to individual variability in amygdala reactivity.
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| 7. |
- Danfors, Torsten, et al.
(author)
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Increased neurokinin-1 receptor availability in temporal lobe epilepsy : A positron emission tomography study using [(11)C]GR205171
- 2011
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In: Epilepsy Research. - : Elsevier BV. - 0920-1211 .- 1872-6844. ; 97:1-2, s. 183-189
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Journal article (peer-reviewed)abstract
- PURPOSE: Activation of the neurokinin-1 (NK1) receptor by neuropeptide substance P (SP) induces and maintains epileptic activity in various experimental models of epilepsy. The primary objective of this study was to investigate whether neurobiological changes linked to NK1-SP receptor system are associated with hyperexcitability in patients with temporal lobe epilepsy (TLE). A secondary objective was to investigate the relationship between seizure frequency and NK1 receptor availability. METHODS: A positron emission tomography study was conducted with the selective NK1 receptor antagonist [(11)C]GR205171 in nine patients with TLE and 18 healthy control participants. Parametric PET images were generated using the Patlak graphical method, with cerebellum as reference region. Data analyses including group comparisons were performed using statistical parametric mapping. RESULTS: Patients with TLE showed increased NK1 receptor availability in both hemispheres with the most pronounced increase in anterior cingulate gyrus ipsilateral to seizure onset. A positive correlation between NK1 receptor availability and seizure frequency was observed in the medial temporal lobe and in the lentiform nucleus ipsilateral to the seizure onset. CONCLUSION: Our results suggest that there is an intrinsic network using the NK1-SP receptor system for synaptic transmission and epileptiform activity in TLE.
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| 8. |
- Eng, W., et al.
(author)
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Occupancy of human brain GABA(A) receptors by the novel alpha 5 subtype-selective benzodiazepine site inverse agonist alpha 5IA as measured using [C-11]flumazenil PET imaging
- 2010
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In: Neuropharmacology. - : Elsevier BV. - 0028-3908 .- 1873-7064. ; 59:7-8, s. 635-639
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Journal article (peer-reviewed)abstract
- GABA(A) receptor alpha 5-selective inverse agonists enhance cognitive performance in pre-clinical species. However, a key aspect of the clinical development of such compounds is the demonstration that in man such compounds are devoid of the anxiogenic-like activity associated with non-selective inverse agonists such as FG 7142. The triazolophthalazine alpha 5IA (3-(5-methylisoxazol-3-yl)-6-[(1-methyl-1,2,3-triazol-4-yl) methyloxy]-1,2,4-triazolo[3,4-a]phthalazine) is an alpha 5-selective inverse agonist which enhances cognitive performance in rodents and encouragingly in human Phase I Safety and Tolerability studies it was devoid of the anxiogenic-like activity associated with FG 7142. However, in order to appropriately interpret this latter observation, it was considered important to demonstrate that the absence of anxiogenic-like activity occurs at significant levels of receptor occupancy. Consequently, the occupancy of human brain GABAA receptors was measured using [C-11]flumazenil positron emission tomography in three healthy normal young male volunteers following a single oral dose of 2 mg alpha 5IA. One hour after dosing, mean occupancy levels were 53% and this fell to 16% by 8 h post-dose, with the plasma alpha 5IA concentration corresponding to 50% occupancy being 10 ng/mL. These data clearly show that an alpha 5-selective inverse agonist is not associated with anxiogenic-like side effects at doses that give 50% occupancy.
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| 9. |
- Engman, Jonas, et al.
(author)
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Age, sex and NK1 receptors in the human brain : A positron emission tomography study with [C-11]GR205171
- 2012
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In: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 22:8, s. 562-568
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Journal article (peer-reviewed)abstract
- The substance P/neurokinin 1 (SP/NK1) system has been implicated in the processing of negative affect. Its role seems complex and findings from animal studies have not been easily translated to humans. Brain imaging studies on NK1 receptor distribution in humans have revealed an abundance of receptors in cortical, striatal and subcortical areas, including the amygdala. A reduction in NK1 receptors with increasing age has been reported in frontal, temporal, and parietal cortices, as well as in hippocampal areas. Also, a previous study suggests sex differences in cortical and subcortical areas, with women displaying fewer NK1 receptors. The present PET study explored NK1 receptor availability in men (n = 9) and women (n = 9) matched for age varying between 20 and 50 years using the highly specific NK1 receptor antagonist [11C]GR205171 and a reference tissue model with cerebellum as the reference region. Age by sex interactions in the amygdala and the temporal cortex reflected a lower NK1 receptor availability with increasing age in men, but not in women. A general age-related decline in NK1 receptor availability was evident in the frontal, temporal, and occipital cortices, as well as in the brainstem, caudate nucleus, and thalamus. Women had lower NK1 receptor availability in the thalamus. The observed pattern of NK1 receptor distribution in the brain might have functional significance for brain-related disorders showing age- and sex-related differences in prevalence.
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| 10. |
- Engman, Jonas, et al.
(author)
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Neural Correlates of Anxiety States in Patients with Social Anxiety Disorder
- 2011
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In: Biological Psychiatry. - 0006-3223 .- 1873-2402. ; 69, s. 70S-70S
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Journal article (other academic/artistic)abstract
- Background: In social anxiety disorder (SAD), the fear of being negatively evaluated by others can restrict individual everyday life, due to the anxiety caused by social interactions. How this anxiety is processed in the brain is only partly understood. We aimed to examine the correlations between subjective anxiety states and brain activity in a large sample of SAD patients, during an anxiety-provoking task.Methods: Data were merged from three randomized clinical PET-trials investigating regional cerebral blood flow (rCBF) during a public speaking task pre- and post treatment (SSRI n = 35, placebo n = 37). All participants met diagnostical criteria for SAD. rCBF was assessed with [15O]-labeled water and state anxiety was measured using the Spielberger state anxiety scale (STAI-S). These measures where then correlated using a covariate of interest approach in Statistical Parametric Mapping (SPM2).Results: rCBF and STAI-S scores correlated positively in the left parahippocampal gyrus and amygdala, as well as in the right premotor cortex (area 6). Negative correlations were observed in the left superior frontal gyrus, thalamus, and the right parahippocampal gyrus. Negative correlations were also found bilaterally in the cerebellum.Conclusions: The correlations between clinical anxiety states and brain activity were noted in areas previously demonstrated to be involved in emotional regulation and motor preparedness.
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