1
|
Endepols H, Apetz N, Vieth L, Lesser C, Schulte-Holtey L, Neumaier B, Drzezga A. Cerebellar Metabolic Connectivity during Treadmill Walking before and after Unilateral Dopamine Depletion in Rats. Int J Mol Sci 2024; 25:8617. [PMID: 39201305 PMCID: PMC11354914 DOI: 10.3390/ijms25168617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 07/26/2024] [Accepted: 08/05/2024] [Indexed: 09/02/2024] Open
Abstract
Compensatory changes in brain connectivity keep motor symptoms mild in prodromal Parkinson's disease. Studying compensation in patients is hampered by the steady progression of the disease and a lack of individual baseline controls. Furthermore, combining fMRI with walking is intricate. We therefore used a seed-based metabolic connectivity analysis based on 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake in a unilateral 6-OHDA rat model. At baseline and in the chronic phase 6-7 months after lesion, rats received an intraperitoneal injection of [18F]FDG and spent 50 min walking on a horizontal treadmill, followed by a brain PET-scan under anesthesia. High activity was found in the cerebellar anterior vermis in both conditions. At baseline, the anterior vermis showed hardly any stable connections to the rest of the brain. The (future) ipsilesional cerebellar hemisphere was not particularly active during walking but was extensively connected to many brain areas. After unilateral dopamine depletion, rats still walked normally without obvious impairments. The ipsilesional cerebellar hemisphere increased its activity, but narrowed its connections down to the vestibulocerebellum, probably aiding lateral stability. The anterior vermis established a network involving the motor cortex, hippocampus and thalamus. Adding those regions to the vermis network of (previously) automatic control of locomotion suggests that after unilateral dopamine depletion considerable conscious and cognitive effort has to be provided to achieve stable walking.
Collapse
Affiliation(s)
- Heike Endepols
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
- Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Nadine Apetz
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
| | - Lukas Vieth
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
| | - Christoph Lesser
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
| | - Léon Schulte-Holtey
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany (L.V.)
- Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany;
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
- Molecular Organization of the Brain (INM-2), Institute of Neuroscience and Medicine, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| |
Collapse
|
2
|
Ju YH, Cho J, Park JY, Kim H, Hong EB, Park KD, Lee CJ, Chung E, Kim HI, Nam MH. Tonic excitation by astrocytic GABA causes neuropathic pain by augmenting neuronal activity and glucose metabolism. Exp Mol Med 2024; 56:1193-1205. [PMID: 38760512 PMCID: PMC11148027 DOI: 10.1038/s12276-024-01232-z] [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: 11/18/2023] [Revised: 02/21/2024] [Accepted: 02/29/2024] [Indexed: 05/19/2024] Open
Abstract
Neuropathic pain is a debilitating condition caused by the hyperexcitability of spinal dorsal horn neurons and is often characterized by allodynia. Although neuron-independent mechanisms of hyperexcitability have been investigated, the contribution of astrocyte-neuron interactions remains unclear. Here, we show evidence of reactive astrocytes and their excessive GABA release in the spinal dorsal horn, which paradoxically leads to the tonic excitation of neighboring neurons in a neuropathic pain model. Using multiple electrophysiological methods, we demonstrated that neuronal hyperexcitability is attributed to both increased astrocytic GABA synthesis via monoamine oxidase B (MAOB) and the depolarized reversal potential of GABA-mediated currents (EGABA) via the downregulation of the neuronal K+/Cl- cotransporter KCC2. Furthermore, longitudinal 2-deoxy-2-[18F]-fluoro-D-glucose microPET imaging demonstrated increased regional glucose metabolism in the ipsilateral dorsal horn, reflecting neuronal hyperexcitability. Importantly, inhibiting MAOB restored the entire astrocytic GABA-mediated cascade and abrogated the increased glucose metabolism and mechanical allodynia. Overall, astrocytic GABA-mediated tonic excitation is critical for neuronal hyperexcitability, leading to mechanical allodynia and neuropathic pain.
Collapse
Affiliation(s)
- Yeon Ha Ju
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jongwook Cho
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Ji-Young Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyunjin Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Eun-Bin Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Ki Duk Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea
| | - Euiheon Chung
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyoung-Ihl Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
- Department of Neurosurgery, Presbyterian Medical Center, Jeonju, 54987, Republic of Korea.
| | - Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
- Department of KHU-KIST Convergence Science and Technology, Kyung Hee University, Seoul, 02447, Republic of Korea.
| |
Collapse
|
3
|
Endepols H, Anglada-Huguet M, Mandelkow E, Neumaier B, Mandelkow EM, Drzezga A. Fragmentation of functional resting state brain networks in a transgenic mouse model of tau pathology: A metabolic connectivity study using [ 18F]FDG-PET. Exp Neurol 2024; 372:114632. [PMID: 38052272 DOI: 10.1016/j.expneurol.2023.114632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/07/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023]
Abstract
In a previous study, regional reductions in cerebral glucose metabolism have been demonstrated in the tauopathy mouse model rTg4510 (Endepols et al., 2022). Notably, glucose hypometabolism was present in some brain regions without co-localized synaptic degeneration measured with [18F]UCB-H. We hypothesized that in those regions hypometabolism may reflect reduced functional connectivity rather than synaptic damage. To test this hypothesis, we performed seed-based metabolic connectivity analyses using [18F]FDG-PET data in this mouse model. Eight rTg4510 mice at the age of seven months and 8 non-transgenic littermates were injected intraperitoneally with 11.1 ± 0.8 MBq [18F]FDG and spent a 35-min uptake period awake in single cages. Subsequently, they were anesthetized and measured in a small animal PET scanner for 30 min. Three seed-based connectivity analyses were performed per group. Seeds were selected for apparent mismatch between [18F]FDG and [18F]UCB-H. A seed was placed either in the medial orbitofrontal cortex, dorsal hippocampus or dorsal thalamus, and correlated with all other voxels of the brain across animals. In the control group, the emerging correlative pattern was strongly overlapping for all three seed locations, indicating a uniform fronto-thalamo-hippocampal resting state network. In contrast, rTg4510 mice showed three distinct networks with minimal overlap. Frontal and thalamic networks were greatly diminished. The hippocampus, however, formed a new network with the whole parietal cortex. We conclude that resting-state functional networks are fragmented in the brain of rTg4510 mice. Thus, hypometabolism can be explained by reduced functional connectivity of brain areas devoid of tau-related pathology, such as the thalamus.
Collapse
Affiliation(s)
- Heike Endepols
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, Cologne, Germany; Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, Jülich 52428, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Nuclear Medicine, Cologne, Germany
| | | | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn-Cologne, Germany; Department Neurodegenerative Diseases & Gerontopsychiatry, University Hospital Bonn, Germany
| | - Bernd Neumaier
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, Cologne, Germany; Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, Jülich 52428, Germany.
| | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn-Cologne, Germany; Department Neurodegenerative Diseases & Gerontopsychiatry, University Hospital Bonn, Germany
| | - Alexander Drzezga
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Nuclear Medicine, Cologne, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn-Cologne, Germany; Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Molecular Organization of the Brain (INM-2), Wilhelm-Johnen-Straße, Jülich 52428, Germany
| |
Collapse
|
4
|
Hascalovici J, Babb A, Norwood BA. Radiotracers in the Diagnosis of Pain: A Mini Review. Semin Musculoskelet Radiol 2023; 27:655-660. [PMID: 37935212 DOI: 10.1055/s-0043-1775743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The diagnosis and understanding of pain is challenging in clinical practice. Assessing pain relies heavily on self-reporting by patients, rendering it inherently subjective. Traditional clinical imaging methods such as computed tomography and magnetic resonance imaging can only detect anatomical abnormalities, offering limited sensitivity and specificity in identifying pain-causing conditions. Radiotracers play a vital role in molecular imaging that aims to identify abnormal biological processes at the cellular level, even in apparently normal anatomical structures. Therefore, molecular imaging is an important area of research as a prospective diagnostic modality for pain-causing pathophysiology. We present a mini review of the current knowledge base regarding radiotracers for identification of pain in vivo. We also describe radiocaine, a novel positron emission tomography imaging agent for sodium channels that has shown great potential for identifying/labeling pain-producing nerves and producing an objectively measurable pain intensity signal.
Collapse
Affiliation(s)
- Jacob Hascalovici
- Relief Medical Group PA, New York, New York
- Saul R. Korey Department of Neurology, The Arthur S. Abramson Department of Physical Medicine and Rehabilitation, Department of Anesthesiology, Albert Einstein College of Medicine, Bronx, New York
| | | | | |
Collapse
|
5
|
Chen P, Wang C, Gong Q, Chai Y, Chen Y, Song C, Wu Y, Wang L. Alterations of endogenous pain-modulatory system of the cerebral cortex in the neuropathic pain. iScience 2023; 26:106668. [PMID: 37168579 PMCID: PMC10165265 DOI: 10.1016/j.isci.2023.106668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/23/2023] [Accepted: 04/11/2023] [Indexed: 05/13/2023] Open
Abstract
Neuropathic pain (NeP) remains a significant clinical challenge owing to insufficient awareness of its pathological mechanisms. We elucidated the aberrant metabolism of the cerebral cortex in NeP induced by the chronic constriction injury (CCI) using metabolomics and proteomics analyses. After CCI surgery, the values of MWT and TWL markedly reduced and maintained at a low level. CCI induced the significant dysregulation of 57 metabolites and 31 proteins in the cerebral cortex. Integrative analyses showed that the differentially expressed metabolites and proteins were primarily involved in alanine, aspartate and glutamate metabolism, GABAergic synapse, and retrograde endocannabinoid signaling. Targeted metabolomics and western blot analysis confirmed the alterations of some key metabolites and proteins in endogenous pain-modulatory system. In conclusion, our study revealed the alterations of endocannabinoids system and purinergic system in the CCI group, and provided a novel perspective on the roles of endogenous pain-modulatory system in the pathological mechanisms of NeP.
Collapse
Affiliation(s)
- Peng Chen
- Basic Medical School, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China
- Corresponding author
| | - Chen Wang
- Department of Traditional Chinese Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou 510282, Guangdong, China
| | - Qian Gong
- First Clinical Medical School, Guangzhou University of Chinese Medicine, Guangzhou 510006, Guangdong, China
| | - Yihui Chai
- Basic Medical School, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China
| | - Yunzhi Chen
- Basic Medical School, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China
| | - Cuiwen Song
- Basic Medical School, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China
| | - Yuanhua Wu
- The First Affiliated Hospital, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China
- Corresponding author
| | - Long Wang
- School of Pharmacy, Southwest Medical University, Luzhou 646000, Sichuan, China
- Corresponding author
| |
Collapse
|
6
|
FDG PET Imaging of the Pain Matrix in Neuropathic Pain Model Rats. Biomedicines 2022; 11:biomedicines11010063. [PMID: 36672571 PMCID: PMC9855331 DOI: 10.3390/biomedicines11010063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/03/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Pain is an unpleasant subjective experience that is usually modified by complex multidimensional neuropsychological processes. Increasing numbers of neuroimaging studies in humans have characterized the hierarchical brain areas forming a pain matrix, which is involved in the different dimensions of pain components. Although mechanistic investigations have been performed extensively in rodents, the homologous brain regions involved in the multidimensional pain components have not been fully understood in the rodent brain. Herein, we successfully identified several brain regions activated in response to mechanical allodynia in neuropathic pain rat models using an alternative neuroimaging method based on 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG PET) scanning. Regions such as the medial prefrontal cortex, primary somatosensory cortex hindlimb region, and the centrolateral thalamic nucleus were identified. Moreover, brain activity in these regions was positively correlated with mechanical allodynia-related behavioral changes. These results suggest that FDG PET imaging in neuropathic pain model rats enables the evaluation of regional brain activity encoding the multidimensional pain aspect. It could thus be a fascinating tool to bridge the gap between preclinical and clinical investigations.
Collapse
|
7
|
Song X, Huang P, Chen X, Xu M, Ming D. The processing network of high-frequency acoustoelectric signal in the living rat brain. J Neural Eng 2022; 19:056013. [PMID: 36044882 DOI: 10.1088/1741-2552/ac8e33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/31/2022] [Indexed: 11/11/2022]
Abstract
Objective.Acoustoelectric brain imaging (ABI) is a potential noninvasive electrophysiological neuroimaging method with high spatiotemporal resolution. At the focal spot of the focused ultrasound, with the couple of acoustic and electric fields, high-frequency acoustoelectric (HF AE) signal is generated. Because the brain is a volume conductor, HF AE signal can be detected in other brain cortex. The processing of HF AE signal is critical for improving decoding precision, further improving the spatial resolution performance of ABI. This study investigates the processing network of HF AE signal in the living rat brain.Approach.When HF AE generated on the left primary visual cortex (V1-L), low-frequency (LF) electroencephalography and HF AE signals on different cortex were recorded at the same time. Firstly, AE signal on different sides of the brain cortex were compared, including prefrontal cortex (FrA) and primary somatosensory cortex (S1FL). Then, we constructed and analyzed functional networks of two signals.Main results.In the same cortex, HF AE signal on the right side had stronger intensity. And compared with LF networks, HF AE network had larger global efficiency and shorter characteristic path length, denoting the stronger processing and transmission of AE signal. Additionally, in HF AE network, the node had significantly increased local properties and the connection were concentrated in the occipital lobe, reflecting the occipital lobe plays an important role in the processing.Significance.Experiment results demonstrate that, compared with LF network, HF AE network is more efficient and had stronger transmission capabilities. And the connection of HF AE network is concentrated in the occipital lobe. This work preliminarily reveals the HF AE signal processing, which is significant for improving the ABI quality and provides a new insight for understanding the brain HF signal.
Collapse
Affiliation(s)
- Xizi Song
- Academy of Medical Engineering and Translational Medicine, Tianjin International Joint Research Centre for Neural Engineering, and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Peishan Huang
- Academy of Medical Engineering and Translational Medicine, Tianjin International Joint Research Centre for Neural Engineering, and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Xinrui Chen
- Academy of Medical Engineering and Translational Medicine, Tianjin International Joint Research Centre for Neural Engineering, and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Minpeng Xu
- Academy of Medical Engineering and Translational Medicine, Tianjin International Joint Research Centre for Neural Engineering, and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin 300072, People's Republic of China
- Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Dong Ming
- Academy of Medical Engineering and Translational Medicine, Tianjin International Joint Research Centre for Neural Engineering, and Tianjin Key Laboratory of Brain Science and Neural Engineering, Tianjin University, Tianjin 300072, People's Republic of China
- Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| |
Collapse
|