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Takechi R, Sharif A, Brook E, Majimbi M, Chan DC, Lam V, Watts GF, Mamo JCL. Is type 2 diabetes associated dementia a microvascular early-Alzheimer's phenotype induced by aberrations in the peripheral metabolism of lipoprotein-amyloid? Front Endocrinol (Lausanne) 2023; 14:1127481. [PMID: 36875491 PMCID: PMC9978204 DOI: 10.3389/fendo.2023.1127481] [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] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 01/18/2023] [Indexed: 02/18/2023] Open
Abstract
There is increasing evidence of a positive association of type 2 diabetes with Alzheimer's disease (AD), the most prevalent form of dementia. Suggested pathways include cerebral vascular dysfunction; central insulin resistance, or exaggerated brain abundance of potentially cytotoxic amyloid-β (Aβ), a hallmark feature of AD. However, contemporary studies find that Aβ is secreted in the periphery by lipogenic organs and secreted as nascent triglyceride-rich lipoproteins (TRL's). Pre-clinical models show that exaggerated abundance in blood of TRL-Aβ compromises blood-brain barrier (BBB) integrity, resulting in extravasation of the TRL-Aβ moiety to brain parenchyme, neurovascular inflammation and neuronal degeneration concomitant with cognitive decline. Inhibiting secretion of TRL-Aβ by peripheral lipogenic organs attenuates the early-AD phenotype indicated in animal models, consistent with causality. Poorly controlled type 2 diabetes commonly features hypertriglyceridemia because of exaggerated TRL secretion and reduced rates of catabolism. Alzheimer's in diabetes may therefore be a consequence of heightened abundance in blood of lipoprotein-Aβ and accelerated breakdown of the BBB. This review reconciles the prevailing dogma of amyloid associated cytotoxicity as a primary risk factor in late-onset AD, with substantial evidence of a microvascular axis for dementia-in-diabetes. Consideration of potentially relevant pharmacotherapies to treat insulin resistance, dyslipidaemia and by extension plasma amyloidemia in type 2 diabetes are discussed.
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Affiliation(s)
- Ryusuke Takechi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Arazu Sharif
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Emily Brook
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Maimuna Majimbi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Dick C. Chan
- Departments of Cardiology and Internal Medicine, Royal Perth Hospital, School of Medicine, University of Western Australia, Perth, WA, Australia
| | - Virginie Lam
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Gerald F. Watts
- Departments of Cardiology and Internal Medicine, Royal Perth Hospital, School of Medicine, University of Western Australia, Perth, WA, Australia
| | - John C. L. Mamo
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- *Correspondence: John C. L. Mamo,
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Majimbi M, Brook E, Galettis P, Eden E, Al-Salami H, Mooranian A, Al-Sallami H, Lam V, Mamo JCL, Takechi R. Sodium alginate microencapsulation improves the short-term oral bioavailability of cannabidiol when administered with deoxycholic acid. PLoS One 2021; 16:e0243858. [PMID: 34138862 PMCID: PMC8211198 DOI: 10.1371/journal.pone.0243858] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 04/13/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cannabidiol (CBD) confers therapeutic effects in some neurological disorders via modulation of inflammatory, oxidative and cell-signalling pathways. However, CBD is lipophilic and highly photooxidative with low oral bioavailability in plasma and brain. In this study, we aimed to design and test a CBD microencapsulation method as a drug delivery strategy to improve the absorption of CBD. Additionally, we evaluated the brain uptake of CBD capsules when administered alongside capsules containing a permeation-modifying bile acid, deoxycholic acid (DCA). METHODS Microcapsules containing either CBD or DCA were formed using the ionic gelation method with 1.5% sodium alginate formulations and 100 mM calcium chloride. C57BL/6J wild type mice randomly assigned to three treatment groups (3-4 mice per group) were administered CBD in the following preparations: 1) CBD capsules, 2) CBD capsules + DCA capsules and 3) naked CBD oil (control). To assess the short-term bioavailability of CBD, plasma and brain samples were collected at 0.3, 1 and 3 hours post administration and CBD levels were analysed with liquid chromatography mass spectrometer. RESULTS We produced spherical capsules at 400 ± 50 μm in size. The CBD capsules were calculated to have a drug loading of 2% and an encapsulation efficiency of 23%. Mice that received CBD capsules + DCA capsules showed a 40% and 47% increase in CBD plasma concentration compared to mice on CBD capsules and naked CBD oil, respectively. Furthermore, the CBD capsules + DCA capsules group showed a 48% and 25% increase in CBD brain concentration compared to mice on CBD capsules and naked CBD oil, respectively. In mice treated with CBD capsules + DCA capsules, the brain CBD concentration peaked at 0.3 hours with a 300% increased availability compared to CBD capsules and naked CBD oil groups, which peaked at 1 hour after administration. CONCLUSIONS The microencapsulation method combined with a permeation enhancer, DCA increased the short-term bioavailability of CBD in plasma and brain.
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Affiliation(s)
- Maimuna Majimbi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Emily Brook
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Peter Galettis
- School of Medicine and Public Health, University of Newcastle and The Australian Centre for Cannabinoid Clinical and Research Excellence, Newcastle, NSW, Australia
| | - Edward Eden
- School of Medicine and Public Health, University of Newcastle and The Australian Centre for Cannabinoid Clinical and Research Excellence, Newcastle, NSW, Australia
| | - Hani Al-Salami
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Armin Mooranian
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | | | - Virginie Lam
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - John C. L. Mamo
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Ryusuke Takechi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
- * E-mail:
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Nesbit M, Mamo JC, Majimbi M, Lam V, Takechi R. Automated Quantitative Analysis of ex vivo Blood-Brain Barrier Permeability Using Intellesis Machine-Learning. Front Neurosci 2021; 15:617221. [PMID: 33935625 PMCID: PMC8086794 DOI: 10.3389/fnins.2021.617221] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/24/2021] [Indexed: 11/13/2022] Open
Abstract
Background An increase in blood brain barrier permeability commonly precedes neuro-inflammation and cognitive impairment in models of dementia. Common methods to estimate capillary permeability have potential confounders, or require laborious and subjective semi-manual analysis. New method Here we used snap frozen mouse and rat brain sections that were double-immunofluorescent labeled for immunoglobulin G (IgG; plasma protein) and laminin-α4 (capillary basement membrane). A Machine Learning Image Analysis program (Zeiss ZEN Intellisis) was trained to recognize and segment laminin-α4 to equivocally identify blood vessels in large sets of images. An IgG subclass based on a threshold intensity was segmented and quantitated only in extravascular regions. The residual parenchymal IgG fluorescence is indicative of blood-to-brain extravasation of IgG and was accurately quantitated. Results Automated machine-learning and threshold based segmentation of only parenchymal IgG extravasation accentuates otherwise indistinct capillary permeability, particularly frequent in minor BBB leakage. Comparison with Existing Methods: Large datasets can be processed and analyzed quickly and robustly to provide an overview of vascular permeability throughout the brain. All human bias or ambiguity involved in classifying and measuring leakage is removed. Conclusion Here we describe a fast and precise method of visualizing and quantitating BBB permeability in mouse and rat brain tissue, while avoiding the confounding influence of unphysiological conditions such as perfusion and eliminating any human related bias from analysis.
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Affiliation(s)
- Michael Nesbit
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - John C Mamo
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Maimuna Majimbi
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Virginie Lam
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Ryusuke Takechi
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,School of Population Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
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Toomey LM, Bartlett CA, Gavriel N, McGonigle T, Majimbi M, Gopalasingam G, Rodger J, Fitzgerald M. Comparing modes of delivery of a combination of ion channel inhibitors for limiting secondary degeneration following partial optic nerve transection. Sci Rep 2019; 9:15297. [PMID: 31653948 PMCID: PMC6814709 DOI: 10.1038/s41598-019-51886-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/07/2019] [Indexed: 11/28/2022] Open
Abstract
Injury to the central nervous system is exacerbated by secondary degeneration. Previous research has shown that a combination of orally and locally administered ion channel inhibitors following partial optic nerve injury protects the myelin sheath and preserves function in the ventral optic nerve, vulnerable to secondary degeneration. However, local administration is often not clinically appropriate. This study aimed to compare the efficacy of systemic and local delivery of the ion channel inhibitor combination of lomerizine, brilliant blue G (BBG) and YM872, which inhibits voltage-gated calcium channels, P2X7 receptors and Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors respectively. Following a partial optic nerve transection, adult female PVG rats were treated with BBG and YM872 delivered via osmotic mini pump directly to the injury site, or via intraperitoneal injection, both alongside oral administration of lomerizine. Myelin structure was preserved with both delivery modes of the ion channel inhibitor combination. However, there was no effect of treatment on inflammation, either peripherally or at the injury site, or on the density of oligodendroglial cells. Taken together, the data indicate that even at lower concentrations, the combinatorial treatment may be preserving myelin structure, and that systemic and local delivery are comparable at improving outcomes following neurotrauma.
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Affiliation(s)
- Lillian M Toomey
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Nikolas Gavriel
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Maimuna Majimbi
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Gopana Gopalasingam
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia.
- Curtin Health Innovation Research Institute, Curtin University, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia.
- Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, 6009, Western Australia, Australia.
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Gopalasingam G, Bartlett CA, McGonigle T, Majimbi M, Warnock A, Ford A, Gough A, Toomey LM, Fitzgerald M. The effects of a combination of ion channel inhibitors on pathology in a model of demyelinating disease. Mult Scler Relat Disord 2019; 34:1-8. [PMID: 31202958 DOI: 10.1016/j.msard.2019.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 05/16/2019] [Accepted: 06/07/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND Multiple sclerosis (MS) has been shown to feature oxidative damage, which can be modelled using the cuprizone model of demyelinating disease. Oxidative damage can occur as a result of excessive influx of calcium ions (Ca2+) and oligodendroglia are particularly vulnerable. However, the effects of limiting excess Ca2+ influx on oxidative damage, oligodendroglia and myelin structure are unknown. OBJECTIVE This study investigated the effects of limiting excess Ca2+ flux on oxidative damage and associated changes in oligodendroglial densities and Node of Ranvier structure in the cuprizone model. METHODS The effects of three weeks of cuprizone administration and of treatment with a combination of three ion channel inhibitors (Lomerizine, Brilliant Blue G (BBG) and YM872), were semi-quantified immunohistochemically. Outcomes assessed were protein nitration (3-nitrotyrosine (3NT)) oxidative damage to DNA (8-hydroxy deoxyguanosine (8OHDG)), advanced glycation end-products (carboxymethyl lysine (CML)), immunoreactivity of microglia (Iba1) and astrocytes (glial acidic fibrillary protein (GFAP)), densities of oligodendrocyte precursor cells (OPCs) (platelet derived growth factor alpha receptor (PDGFαR) with olig2) and oligodendrocytes (olig2 and CC1), and structural elements of the Node of Ranvier (contactin associated protein (Caspr)). RESULTS The administration of cuprizone resulted in increased protein nitration, DNA damage, and astrocyte and microglial immunoreactivity, a decrease in the density of oligodendrocytes and OPCs, together with altered structure of the Node of Ranvier and reduced myelin basic protein immunoreactivity. Treatment with the ion channel inhibitor combination significantly lowered protein nitration, increased the density of OPCs and reduced the number of atypical Node of Ranvier complexes; other outcomes were unaffected. CONCLUSION Our findings suggest that excess Ca2+ influx contributes to protein nitration, and associated changes to OPC densities and Node of Ranvier structure in demyelinating disease.
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Affiliation(s)
- Gopana Gopalasingam
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia; School of Human Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Belmont, Western Australia, Australia
| | - Maimuna Majimbi
- Curtin Health Innovation Research Institute, Curtin University, Belmont, Western Australia, Australia
| | - Andrew Warnock
- Curtin Health Innovation Research Institute, Curtin University, Belmont, Western Australia, Australia
| | - Abbey Ford
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia
| | - Alexander Gough
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia
| | - Lillian M Toomey
- Curtin Health Innovation Research Institute, Curtin University, Belmont, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, Western Australia 6009, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Nedlands, Western Australia 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, 8 Verdun St, Nedlands, Western Australia 6009, Australia.
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Hackett MJ, Hollings A, Majimbi M, Brook E, Cochran B, Giles C, Lam V, Nesbit M, Rye KA, Mamo JCL, Takechi R. Multimodal Imaging Analyses of Brain Hippocampal Formation Reveal Reduced Cu and Lipid Content and Increased Lactate Content in Non-Insulin-Dependent Diabetic Mice. ACS Chem Neurosci 2019; 10:2533-2540. [PMID: 30855947 DOI: 10.1021/acschemneuro.9b00039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Non-insulin-dependent diabetes mellitus (NIDDM) is reported to increase the risk of cognitive impairment and dementia. However, the underlying mechanisms are not fully understood. While the brain homeostasis of metals and lipids is pivotal to maintaining energy metabolism and redox homeostasis for healthy brain function, no studies have reported hippocampal metal and biochemical changes in NIDDM. Therefore, we here utilized direct spectroscopic imaging to reveal the elemental distribution within the hippocampal subregions of an established murine model of NIDDM, db/db mice. In 26-week-old insulin resistant db/db mice, X-ray fluorescence microscopy revealed that the Cu content within the dentate gyrus and CA3 was significantly greater than that of the age-matched nondiabetic control mice. In addition, Fourier transform infrared (FTIR) spectroscopy analysis indicated a significant increase in the abundance of lactate within the corpus callosum (CC), dentate gyrus, CA1, and CA3 regions of diabetic db/db mice compared to that of the control, indicating altered energy metabolism. FTIR analysis also showed a significant decrease in the level of lipid methylene and ester within the CC of db/db mice. Furthermore, immunomicroscopy analyses demonstrated the increase in the level of glial fibrillary acidic protein expression and peri-vascular extravasation of IgG, indicating astrogliosis and blood-brain barrier dysfunction, respectively. These data suggest that astrogliosis-induced alterations in the supply of Cu, lipids, and energy substrates may be involved in the mechanisms of NIDDM-associated cognitive decline.
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Affiliation(s)
- Mark J. Hackett
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Science, Faculty of Science and Engineering, Curtin University, Bentley, WA 6102, Australia
| | - Ashley Hollings
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Science, Faculty of Science and Engineering, Curtin University, Bentley, WA 6102, Australia
| | - Maimuna Majimbi
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Emily Brook
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Blake Cochran
- School of Medical Sciences, Faculty of Medicine, UNSW, Sydney, NSW 2052, Australia
| | - Corey Giles
- Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Virginie Lam
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Michael Nesbit
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Kerry-Anne Rye
- School of Medical Sciences, Faculty of Medicine, UNSW, Sydney, NSW 2052, Australia
| | - John C. L. Mamo
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Ryusuke Takechi
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
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Fehily B, Bartlett CA, Lydiard S, Archer M, Milbourn H, Majimbi M, Hemmi JM, Dunlop SA, Yates NJ, Fitzgerald M. Differential responses to increasing numbers of mild traumatic brain injury in a rodent closed-head injury model. J Neurochem 2019; 149:660-678. [PMID: 30702755 DOI: 10.1111/jnc.14673] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/20/2018] [Accepted: 01/14/2019] [Indexed: 01/13/2023]
Abstract
Following mild traumatic brain injury (mTBI), further mild impacts can exacerbate negative outcomes. To compare chronic damage and deficits following increasing numbers of repeated mTBIs, a closed-head weight-drop model of repeated mTBI was used to deliver 1, 2 or 3 mTBIs to adult female rats at 24 h intervals. Outcomes were assessed at 3 months following the first mTBI. No gross motor, sensory or reflex deficits were identified (p > 0.05), consistent with current literature. Cognitive function assessed using a Morris water maze revealed chronic memory deficits following 1 and 2, but not 3 mTBI compared to shams (p ≤ 0.05). Oxidative damage to DNA was assessed immunohistochemically in the dentate hilus of the hippocampus and splenium of the corpus callosum; no changes were observed. IBA1-positive microglia were increased in size in the cortex following 1 mTBI and in the corpus callosum following 2 mTBI compared to shams (p ≤ 0.05); no changes were observed in the dentate hilus. Glial fibrillary acidic protein (GFAP)-positive astrocyte immunoreactivity was assessed in all three brain regions and no chronic changes were observed. Integrity of myelin ultrastructure in the corpus callosum was assessed using transmission electron microscopy. G ratio was decreased following 2 mTBIs compared to shams (p ≤ 0.05) at post hoc level only. The changing patterns of damage and deficits following increasing numbers of mTBI may reflect dynamic responses to small numbers of mTBIs or a conditioning effect such that increasing numbers of mTBIs do not necessarily result in worsening pathology. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/. Cover Image for this issue: doi: 10.1111/jnc.14508.
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Affiliation(s)
- Brooke Fehily
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Stephen Lydiard
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Michael Archer
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Hannah Milbourn
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Maimuna Majimbi
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Bentley, WA, Australia
| | - Jan M Hemmi
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Sarah A Dunlop
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
| | - Nathanael J Yates
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, Crawley, WA, Australia
- Curtin Health Innovation Research Institute, Faculty of Health Sciences, Bentley, WA, Australia
- The Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute Building, Nedlands, WA, Australia
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8
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Tavner A, Roy TD, Hor K, Majimbi M, Joldes G, Wittek A, Bunt S, Miller K. On the appropriateness of modelling brain parenchyma as a biphasic continuum. J Mech Behav Biomed Mater 2016; 61:511-518. [DOI: 10.1016/j.jmbbm.2016.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/06/2016] [Accepted: 04/06/2016] [Indexed: 10/21/2022]
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