Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes
Unwanted proteins and metabolic waste in cerebral spinal fluid are cleared from the brain by meningeal and nasal lymphatics and the perineural sheath of cranial nerves; however, the distribution and clearance of cerebral spinal fluid (CSF) along the subarachnoid space of the entire spinal cord is no...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Journal of Imaging |
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| Online Access: | https://www.mdpi.com/2313-433X/9/2/45 |
| _version_ | 1797620112861167616 |
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| author | Christian Stokes Eli F White Steve Toddes Nicole Bens Praveen Kulkarni Craig F Ferris |
| author_facet | Christian Stokes Eli F White Steve Toddes Nicole Bens Praveen Kulkarni Craig F Ferris |
| author_sort | Christian Stokes |
| collection | DOAJ |
| description | Unwanted proteins and metabolic waste in cerebral spinal fluid are cleared from the brain by meningeal and nasal lymphatics and the perineural sheath of cranial nerves; however, the distribution and clearance of cerebral spinal fluid (CSF) along the subarachnoid space of the entire spinal cord is not fully understood. Cryo-fluorescence tomography (CFT) was used to follow the movement of tracers from the ventricular system of the brain down through the meningeal lining of the spinal cord and out to the spinal lymphatic nodes. Isoflurane-anesthetized mice were infused into the lateral cerebroventricle with 5.0 µL of quantum dots [QdotR 605 ITKTM amino (PEG)] over two mins. Mice were allowed to recover (ca 2–3 min) and remained awake and ambulatory for 5, 15, 30, 60, and 120 min after which they were euthanized, and the entire intact body was frozen at −80<sup>°</sup>. The entire mouse was sectioned, and white light and fluorescent images were captured after each slice to produce high resolution three-dimensional volumes. Tracer appeared throughout the ventricular system and central canal of the spinal cord and the entire subarachnoid space of the CNS. A signal could be visualized in the nasal cavity, deep cervical lymph nodes, thoracic lymph nodes, and more superficial submandibular lymph nodes as early as 15 min post infusion. A fluorescent signal could be visualized along the dorsal root ganglia and down the proximal extension of the spinal nerves of the thoracic and lumbar segments at 30 min. There was a significant accumulation of tracer in the lumbar and sacral lymph nodes between 15–60 min. The dense fluorescent signal in the thoracic vertebrae noted at 5- and 15-min post infusion was significantly reduced by 30 min. Indeed, all signals in the spinal cord were ostensibly absent by 120 min, except for trace amounts in the coccyx. The brain still had some residual signal at 120 min. These data show that Qdots with a hydrodynamic diameter of 16–20 nm rapidly clear from the brain of awake mice. These data also clearly demonstrate the rapid distribution and efflux of traces along a major length of the vertebral column and the potential contribution of the spinal cord in the clearance of brain waste. |
| first_indexed | 2024-03-11T08:36:27Z |
| format | Article |
| id | doaj.art-41358e9109264871924bc5589694bbb7 |
| institution | Directory Open Access Journal |
| issn | 2313-433X |
| language | English |
| last_indexed | 2024-03-11T08:36:27Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Imaging |
| spelling | doaj.art-41358e9109264871924bc5589694bbb72023-11-16T21:25:15ZengMDPI AGJournal of Imaging2313-433X2023-02-01924510.3390/jimaging9020045Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph NodesChristian Stokes0Eli F White1Steve Toddes2Nicole Bens3Praveen Kulkarni4Craig F Ferris5EMIT Imaging, Baltimore, MD 21201, USAEMIT Imaging, Baltimore, MD 21201, USAEMIT Imaging, Baltimore, MD 21201, USACenter for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USACenter for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USACenter for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USAUnwanted proteins and metabolic waste in cerebral spinal fluid are cleared from the brain by meningeal and nasal lymphatics and the perineural sheath of cranial nerves; however, the distribution and clearance of cerebral spinal fluid (CSF) along the subarachnoid space of the entire spinal cord is not fully understood. Cryo-fluorescence tomography (CFT) was used to follow the movement of tracers from the ventricular system of the brain down through the meningeal lining of the spinal cord and out to the spinal lymphatic nodes. Isoflurane-anesthetized mice were infused into the lateral cerebroventricle with 5.0 µL of quantum dots [QdotR 605 ITKTM amino (PEG)] over two mins. Mice were allowed to recover (ca 2–3 min) and remained awake and ambulatory for 5, 15, 30, 60, and 120 min after which they were euthanized, and the entire intact body was frozen at −80<sup>°</sup>. The entire mouse was sectioned, and white light and fluorescent images were captured after each slice to produce high resolution three-dimensional volumes. Tracer appeared throughout the ventricular system and central canal of the spinal cord and the entire subarachnoid space of the CNS. A signal could be visualized in the nasal cavity, deep cervical lymph nodes, thoracic lymph nodes, and more superficial submandibular lymph nodes as early as 15 min post infusion. A fluorescent signal could be visualized along the dorsal root ganglia and down the proximal extension of the spinal nerves of the thoracic and lumbar segments at 30 min. There was a significant accumulation of tracer in the lumbar and sacral lymph nodes between 15–60 min. The dense fluorescent signal in the thoracic vertebrae noted at 5- and 15-min post infusion was significantly reduced by 30 min. Indeed, all signals in the spinal cord were ostensibly absent by 120 min, except for trace amounts in the coccyx. The brain still had some residual signal at 120 min. These data show that Qdots with a hydrodynamic diameter of 16–20 nm rapidly clear from the brain of awake mice. These data also clearly demonstrate the rapid distribution and efflux of traces along a major length of the vertebral column and the potential contribution of the spinal cord in the clearance of brain waste.https://www.mdpi.com/2313-433X/9/2/45brain clearanceQdotsnasal turbinatessubarachnoid spacecervical lymphaticssympathetic ganglia |
| spellingShingle | Christian Stokes Eli F White Steve Toddes Nicole Bens Praveen Kulkarni Craig F Ferris Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes Journal of Imaging brain clearance Qdots nasal turbinates subarachnoid space cervical lymphatics sympathetic ganglia |
| title | Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes |
| title_full | Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes |
| title_fullStr | Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes |
| title_full_unstemmed | Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes |
| title_short | Whole CNS 3D Cryo-Fluorescence Tomography Shows CSF Clearance along Nasal Lymphatics, Spinal Nerves, and Lumbar/Sacral Lymph Nodes |
| title_sort | whole cns 3d cryo fluorescence tomography shows csf clearance along nasal lymphatics spinal nerves and lumbar sacral lymph nodes |
| topic | brain clearance Qdots nasal turbinates subarachnoid space cervical lymphatics sympathetic ganglia |
| url | https://www.mdpi.com/2313-433X/9/2/45 |
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