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Ahluwalia M, Mcmichael H, Kumar M, Espinosa MP, Bosomtwi A, Lu Y, Khodadadi H, Jarrahi A, Khan MB, Hess DC, Rahimi SY, Vender JR, Vale FL, Braun M, Baban B, Dhandapani KM, Vaibhav K. Altered endocannabinoid metabolism compromises the brain-CSF barrier and exacerbates chronic deficits after traumatic brain injury in mice. Exp Neurol 2023; 361:114320. [PMID: 36627040 PMCID: PMC9904276 DOI: 10.1016/j.expneurol.2023.114320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/07/2022] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
Endocannabinoids [2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA)], endogenously produced arachidonate-based lipids, are anti-inflammatory physiological ligands for two known cannabinoid receptors, CB1 and CB2, yet the molecular and cellular mechanisms underlying their effects after brain injury are poorly defined. In the present study, we hypothesize that traumatic brain injury (TBI)-induced loss of endocannabinoids exaggerates neurovascular injury, compromises brain-cerebrospinal fluid (CSF) barriers (BCB) and causes behavioral dysfunction. Preliminary analysis in human CSF and plasma indicates changes in endocannabinoid levels. This encouraged us to investigate the levels of endocannabinoid-metabolizing enzymes in a mouse model of controlled cortical impact (CCI). Reductions in endocannabinoid (2-AG and AEA) levels in plasma were supported by higher expression of their respective metabolizing enzymes, monoacylglycerol lipase (MAGL), fatty acid amide hydrolase (FAAH), and cyclooxygenase 2 (Cox-2) in the post-TBI mouse brain. Following increased metabolism of endocannabinoids post-TBI, we observed increased expression of CB2, non-cannabinoid receptor Transient receptor potential vanilloid-1 (TRPV1), aquaporin 4 (AQP4), ionized calcium binding adaptor molecule 1 (IBA1), glial fibrillary acidic protein (GFAP), and acute reduction in cerebral blood flow (CBF). The BCB and pericontusional cortex showed altered endocannabinoid expressions and reduction in ventricular volume. Finally, loss of motor functions and induced anxiety behaviors were observed in these TBI mice. Taken together, our findings suggest endocannabinoids and their metabolizing enzymes play an important role in the brain and BCB integrity and highlight the need for more extensive studies on these mechanisms.
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Affiliation(s)
- Meenakshi Ahluwalia
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Hannah Mcmichael
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Manish Kumar
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Mario P Espinosa
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Asamoah Bosomtwi
- Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Hesam Khodadadi
- Department of Oral Biology and Diagnostic Sciences, Center for Excellence in Research, Scholarship and Innovation, Dental College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Abbas Jarrahi
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Mohammad Badruzzaman Khan
- Department of Neurology, Neuroscience Center of Excellence, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - David C Hess
- Department of Neurology, Neuroscience Center of Excellence, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Scott Y Rahimi
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - John R Vender
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Fernando L Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Molly Braun
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America; Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States of America; VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Babak Baban
- Department of Oral Biology and Diagnostic Sciences, Center for Excellence in Research, Scholarship and Innovation, Dental College of Georgia, Augusta University, Augusta, GA, United States of America; Department of Neurology, Neuroscience Center of Excellence, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Krishnan M Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Kumar Vaibhav
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States of America; Department of Oral Biology and Diagnostic Sciences, Center for Excellence in Research, Scholarship and Innovation, Dental College of Georgia, Augusta University, Augusta, GA, United States of America.
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Ssali T, Anazodo UC, Narciso L, Liu L, Jesso S, Richardson L, Günther M, Konstandin S, Eickel K, Prato F, Finger E, St Lawrence K. Sensitivity of arterial Spin labeling for characterization of longitudinal perfusion changes in Frontotemporal dementia and related disorders. Neuroimage Clin 2021; 35:102853. [PMID: 34697009 PMCID: PMC9421452 DOI: 10.1016/j.nicl.2021.102853] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/24/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
Abstract
This study demonstrates the value of ASL for longitudinal monitoring of perfusion in FTD patients. Good agreement was found in repeat measures of CBF in patients and controls. Transit times were not a significant source of error for the selected post labeling delay (2 s).
Background Advances in the understanding of the pathophysiology of frontotemporal dementia (FTD) and related disorders, along with the development of novel candidate disease modifying treatments, have stimulated the need for tools to assess the efficacy of new therapies. While perfusion imaging by arterial spin labeling (ASL) is an attractive approach for longitudinal imaging biomarkers of neurodegeneration, sources of variability between sessions including arterial transit times (ATT) and fluctuations in resting perfusion can reduce its sensitivity. Establishing the magnitude of perfusion changes that can be reliably detected is necessary to delineate longitudinal perfusion changes related to disease processes from the effects of these sources of error. Purpose To assess the feasibility of ASL for longitudinal monitoring of patients with FTD by quantifying between-session variability of perfusion on a voxel-by-voxel basis. Methods and materials ASL data were collected in 13 healthy controls and 8 patients with FTD or progressive supra-nuclear palsy. Variability in cerebral blood flow (CBF) by single delay pseudo-continuous ASL (SD-pCASL) acquired one month apart were quantified by the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Additionally, CBF by SD-pCASL and ATT by low-resolution multiple inversion time ASL (LowRes-pCASL) were compared to Hadamard encoded sequences which are able to simultaneously measure CBF and ATT with improved time-efficiency. Results Agreement of grey-matter perfusion between sessions was found for both patients and controls (CV = 10.8% and 8.3% respectively) with good reliability for both groups (ICC > 0.6). Intensity normalization to remove day-to-day fluctuations in resting perfusion reduced the CV by 28%. Less than 5% of voxels had ATTs above the chosen post labelling delay (2 s), indicating that the ATT was not a significant source of error. Hadamard-encoded perfusion imaging yielded systematically higher CBF compared to SD-pCASL, but produced similar transit-time measurements. Power analysis revealed that SD-pCASL has the sensitivity to detect longitudinal changes as low as 10% with as few as 10 patient participants. Conclusion With the appropriate labeling parameters, SD-pCASL is a promising approach for assessing longitudinal changes in CBF associated with FTD.
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Affiliation(s)
- Tracy Ssali
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada.
| | - Udunna C Anazodo
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Lucas Narciso
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Linshan Liu
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Sarah Jesso
- Lawson Health Research Institute, London, Canada; St. Joseph's Health Care, London, Canada
| | - Lauryn Richardson
- Lawson Health Research Institute, London, Canada; St. Joseph's Health Care, London, Canada
| | - Matthias Günther
- Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany; University Bremen, Bremen, Germany
| | - Simon Konstandin
- Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany; Mediri GmbH, Heidelberg, Germany
| | | | - Frank Prato
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Elizabeth Finger
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada; Department of Clinical Neurological Sciences, Western University, London, Canada
| | - Keith St Lawrence
- Lawson Health Research Institute, London, Canada; Department of Medical Biophysics, Western University, London, Canada
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Rubinski A, Tosun D, Franzmeier N, Neitzel J, Frontzkowski L, Weiner M, Ewers M. Lower cerebral perfusion is associated with tau-PET in the entorhinal cortex across the Alzheimer's continuum. Neurobiol Aging 2021; 102:111-8. [PMID: 33765424 DOI: 10.1016/j.neurobiolaging.2021.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/01/2021] [Accepted: 02/04/2021] [Indexed: 12/28/2022]
Abstract
Alzheimer's disease (AD) is associated with reduced temporo-parietal cerebral blood flow (CBF). However, a substantial variability in CBF across the clinical spectrum of AD has been reported, possibly due to differences in primary AD pathologies. Here, we assessed CBF (ASL-MRI), tau (AV1451-PET) and amyloid (AV45/FBB-PET) in 156 subjects across the AD continuum. Using mixed-effect regression analyses, we assessed the local associations between amyloid-PET, tau-PET and CBF in a hypothesis-driven way focusing on each pathology's predilection areas. The contribution of Apolipoprotein E (APOE) genotype, and MRI markers of small vessel disease (SVD) to alterations in CBF were assessed as well. Tau-PET was associated with lower CBF in the entorhinal cortex, independent of Aβ. Amyloid-PET was associated with lower CBF in temporo-parietal regions. No associations between MRI markers of SVD and CBF were observed. These results provide evidence that in addition to Aβ, pathologic tau is a major correlate of CBF in early Braak stages, independent of Aβ, APOE genotype and SVD markers.
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