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Almasabi F, Alosaimi F, Corrales-Terrón M, Wolters A, Strikwerda D, Smit JV, Temel Y, Janssen MLF, Jahanshahi A. Post-Mortem Analysis of Neuropathological Changes in Human Tinnitus. Brain Sci 2022; 12:brainsci12081024. [PMID: 36009087 PMCID: PMC9406157 DOI: 10.3390/brainsci12081024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 12/04/2022] Open
Abstract
Tinnitus is the phantom perception of a sound, often accompanied by increased anxiety and depressive symptoms. Degenerative or inflammatory processes, as well as changes in monoaminergic systems, have been suggested as potential underlying mechanisms. Herein, we conducted the first post-mortem histopathological assessment to reveal detailed structural changes in tinnitus patients’ auditory and non-auditory brain regions. Tissue blocks containing the medial geniculate body (MGB), thalamic reticular nucleus (TRN), central part of the inferior colliculus (CIC), and dorsal and obscurus raphe nuclei (DRN and ROb) were obtained from tinnitus patients and matched controls. Cell density and size were assessed in Nissl-stained sections. Astrocytes and microglia were assessed using immunohistochemistry. The DRN was stained using antibodies raised against phenylalanine hydroxylase-8 (PH8) and tyrosine-hydroxylase (TH) to visualize serotonergic and dopaminergic cells, respectively. Cell density in the MGB and CIC of tinnitus patients was reduced, accompanied by a reduction in the number of astrocytes in the CIC only. Quantification of cell surface size did not reveal any significant difference in any of the investigated brain regions between groups. The number of PH8-positive cells was reduced in the DRN and ROb of tinnitus patients compared to controls, while the number of TH-positive cells remained unchanged in the DRN. These findings suggest that both neurodegenerative and inflammatory processes in the MGB and CIC underlie the neuropathology of tinnitus. Moreover, the reduced number of serotonergic cell bodies in tinnitus cases points toward a potential role of the raphe serotonergic system in tinnitus.
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Affiliation(s)
- Faris Almasabi
- Department of Neurosurgery, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (F.A.); (F.A.); (Y.T.)
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
- Department of Physiology, Faculty of Medicine, King Khalid University, Abha 62529, Saudi Arabia
| | - Faisal Alosaimi
- Department of Neurosurgery, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (F.A.); (F.A.); (Y.T.)
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
- Department of Physiology, Faculty of Medicine, King Abdulaziz University, Rabigh 25732, Saudi Arabia
| | - Minerva Corrales-Terrón
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
| | - Anouk Wolters
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
| | - Dario Strikwerda
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
| | - Jasper V. Smit
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
- Department of Ear, Nose, Throat, Head and Neck Surgery, Zuyderland Medical Center, 6419 PC Heerlen, The Netherlands
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (F.A.); (F.A.); (Y.T.)
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
| | - Marcus L. F. Janssen
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
- Department of Clinical Neurophysiology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands
| | - Ali Jahanshahi
- Department of Neurosurgery, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (F.A.); (F.A.); (Y.T.)
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (M.C.-T.); (A.W.); (D.S.); (J.V.S.); (M.L.F.J.)
- Correspondence:
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