Mikko Aarnio1, Lieuwe Appel2, Mats Fredrikson3, Torsten Gordh4, Olof Wolf5, Jens Sörensen2, Måns Thulin6, Magnus Peterson7, Clas Linnman8. 1. Department of Surgical Sciences, Anesthesiology and Intensive Care Medicine, Uppsala University Hospital, Sweden. Electronic address: mikko.aarnio@surgsci.uu.se. 2. PET Centre, Department of Medical Imaging, Uppsala University Hospital, Sweden; Section of Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Sweden. 3. Department of Psychology, Uppsala University, Sweden; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden. 4. Department of Surgical Sciences, Anesthesiology and Intensive Care Medicine, Uppsala University Hospital, Sweden. 5. Department of Surgical Sciences, Orthopedics, Uppsala University Hospital, Sweden. 6. Department of Statistics, Uppsala University, Sweden. 7. Department of Public Health and Caring Sciences, Section of Family Medicine and Preventive Medicine, Uppsala University, Sweden. 8. Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
Abstract
BACKGROUND AND AIMS: Positron emission tomography (PET) with the radioligand [11C]-D-deprenyl has shown increased signal at location of pain in patients with rheumatoid arthritis and chronic whiplash injury. The binding site of [11C]-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 [11C]-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 [11C]-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 [11C]-D-deprenyl PET/CT in the acute phase, at one month and 6-14 months after injury. RESULTS: Acute [11C]-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, [11C]-D-deprenyl uptake decreased, but did not normalize until after 11 months. Patients experiencing persistent pain had prolonged [11C]-D-deprenyl uptake in painful locations. CONCLUSIONS AND IMPLICATIONS: The data provide further support that [11C]-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.
BACKGROUND AND AIMS: Positron emission tomography (PET) with the radioligand [11C]-D-deprenyl has shown increased signal at location of pain in patients with rheumatoid arthritis and chronic whiplash injury. The binding site of [11C]-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 [11C]-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 [11C]-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 [11C]-D-deprenyl PET/CT in the acute phase, at one month and 6-14 months after injury. RESULTS: Acute [11C]-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, [11C]-D-deprenyl uptake decreased, but did not normalize until after 11 months. Patients experiencing persistent pain had prolonged [11C]-D-deprenyl uptake in painful locations. CONCLUSIONS AND IMPLICATIONS: The data provide further support that [11C]-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.
Authors: Karen D Davis; Nima Aghaeepour; Andrew H Ahn; Martin S Angst; David Borsook; Ashley Brenton; Michael E Burczynski; Christopher Crean; Robert Edwards; Brice Gaudilliere; Georgene W Hergenroeder; Michael J Iadarola; Smriti Iyengar; Yunyun Jiang; Jiang-Ti Kong; Sean Mackey; Carl Y Saab; Christine N Sang; Joachim Scholz; Marta Segerdahl; Irene Tracey; Christin Veasley; Jing Wang; Tor D Wager; Ajay D Wasan; Mary Ann Pelleymounter Journal: Nat Rev Neurol Date: 2020-06-15 Impact factor: 42.937