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Zhou C, Zhu X, Li J, Luo Y, Zhou Y. Dynamic assessment of brain perfusion in a middle cerebral artery occlusion rat model by contrast-enhanced ultrasound imaging: a pilot study. Acta Radiol 2023; 64:3042-3051. [PMID: 37872652 DOI: 10.1177/02841851231205163] [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] [Indexed: 10/25/2023]
Abstract
BACKGROUND The middle cerebral artery occlusion model (MCAo) is a commonly used animal model for cerebral ischemia studies but lacks accessible imaging techniques for the assessment of hemodynamic changes of the model. PURPOSE The study aims to explore the value of contrast-enhanced ultrasound (CEUS) in evaluating brain perfusion in the early stages after MCAo surgery. MATERIAL AND METHODS In total, 18 adult male Sprague-Dawley rats were subjected to right MCAo using an intraluminal filament model, and CEUS was performed at the three following timepoints: before (T0), immediately after (T1), and 6 h after permanent MCAo (T2). Twelve rats successfully completed the study, and their brains were removed and stained using 2, 3, 5-triphenyltetrazolium chloride (TTC). CEUS video images were visualized offline, and the time-intensity curves (TICs) were analyzed. Different cerebrovascular patterns and manifestations of the contrast enhancement in rat ischemic hemispheres were observed. Semi-quantitative parameters of TICs in ischemic areas (ROIi) and the surrounding normal- or hypo-perfused areas (ROIn) were calculated and compared between T0, T1, and T2, and also between ROIi and ROIn. RESULTS A significant correlation was found between the lesion volume (%) determined by TTC and CEUS parameters (r = -0.691, P = 0.013 for peak intensity; r = -0.742, P = 0.006 for area under the curve) at T2. After the same occlusion, there were differences in contrast perfusion in each group. CONCLUSION This study suggests that CEUS could be an effective imaging tool for studying cerebral ischemia and perfusion in small animals as long as the transcranial acoustic window allows it.
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Affiliation(s)
- Chenyun Zhou
- Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, Sichuan, PR China
| | - Xiaoxia Zhu
- Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, Sichuan, PR China
| | - Jin Li
- Department of Neurosurgery, West China Hospital of Sichuan University, Chengdu, Sichuan, PR China
| | - Yan Luo
- Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, Sichuan, PR China
| | - Yuqing Zhou
- Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, Sichuan, PR China
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Omileke D, Bothwell SW, Pepperall D, Beard DJ, Coupland K, Patabendige A, Spratt NJ. Decreased Intracranial Pressure Elevation and Cerebrospinal Fluid Outflow Resistance: A Potential Mechanism of Hypothermia Cerebroprotection Following Experimental Stroke. Brain Sci 2021; 11:brainsci11121589. [PMID: 34942890 PMCID: PMC8699790 DOI: 10.3390/brainsci11121589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/23/2021] [Accepted: 11/28/2021] [Indexed: 12/02/2022] Open
Abstract
Background: Elevated intracranial pressure (ICP) occurs 18–24 h after ischaemic stroke and is implicated as a potential cause of early neurological deterioration. Increased resistance to cerebrospinal fluid (CSF) outflow after ischaemic stroke is a proposed mechanism for ICP elevation. Ultra-short duration hypothermia prevents ICP elevation 24 h post-stroke in rats. We aimed to determine whether hypothermia would reduce CSF outflow resistance post-stroke. Methods: Transient middle cerebral artery occlusion was performed, followed by gradual cooling to 33 °C. At 18 h post-stroke, CSF outflow resistance was measured using a steady-state infusion method. Results: Hypothermia to 33 °C prevented ICP elevation 18 h post-stroke (hypothermia ∆ICP = 0.8 ± 3.6 mmHg vs. normothermia ∆ICP = 4.4 ± 2.0 mmHg, p = 0.04) and reduced infarct volume 24 h post-stroke (hypothermia = 78.6 ± 21.3 mm3 vs. normothermia = 108.1 ± 17.8 mm3; p = 0.01). Hypothermia to 33 °C did not result in a significant reduction in CSF outflow resistance compared with normothermia controls (0.32 ± 0.36 mmHg/µL/min vs. 1.07 ± 0.99 mmHg/µL/min, p = 0.06). Conclusions: Hypothermia treatment was protective in terms of ICP rise prevention, infarct volume reduction, and may be implicated in CSF outflow resistance post-stroke. Further investigations are warranted to elucidate the mechanisms of ICP elevation and hypothermia treatment.
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Affiliation(s)
- Daniel Omileke
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Steven W. Bothwell
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Debbie Pepperall
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Daniel J. Beard
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Kirsten Coupland
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
| | - Adjanie Patabendige
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Wirral CH64 7TE, UK
- Department of Biology, Edge Hill University, Ormskirk L39 4QP, UK
- Correspondence: (A.P.); (N.J.S.)
| | - Neil J. Spratt
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; (D.O.); (S.W.B.); (D.P.); (D.J.B.); (K.C.)
- Hunter Medical Research Institute, New Lambton Heights, Newcastle, NSW 2305, Australia
- Hunter New England Local Health District, New Lambton Heights, Newcastle, NSW 2305, Australia
- Correspondence: (A.P.); (N.J.S.)
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3
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Short-duration hypothermia completed prior to reperfusion prevents intracranial pressure elevation following ischaemic stroke in rats. Sci Rep 2021; 11:22354. [PMID: 34785754 PMCID: PMC8595681 DOI: 10.1038/s41598-021-01838-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/01/2021] [Indexed: 11/08/2022] Open
Abstract
Reperfusion therapies re-establish blood flow after arterial occlusion and improve outcome for ischaemic stroke patients. Intracranial pressure (ICP) elevation occurs 18-24 h after experimental stroke. This elevation is prevented by short-duration hypothermia spanning the time of reperfusion. We aimed to determine whether hypothermia-rewarming completed prior to reperfusion, also prevents ICP elevation 24 h post-stroke. Transient middle cerebral artery occlusion was performed on male outbred Wistar rats. Sixty-minute hypothermia to 33 °C, followed by rewarming was induced prior to reperfusion in one group, and after reperfusion in another group. Normothermia controls received identical anaesthesia protocols. ΔICP from pre-stroke to 24 h post-stroke was measured, and infarct volumes were calculated. Rewarming pre-reperfusion prevented ICP elevation (ΔICP = 0.3 ± 3.9 mmHg vs. normothermia ΔICP = 5.2 ± 2.1 mmHg, p = 0.02) and reduced infarct volume (pre-reperfusion = 78.6 ± 23.7 mm3 vs. normothermia = 125.1 ± 44.3 mm3, p = 0.04) 24 h post-stroke. There were no significant differences in ΔICP or infarct volumes between hypothermia groups rewarmed pre- or post-reperfusion. Hypothermia during reperfusion is not necessary for prevention of ICP rise or infarct volume reduction. Short-duration hypothermia may be an applicable early treatment strategy for stroke patients prior to- during-, and after reperfusion therapy.
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Omileke D, Pepperall D, Bothwell SW, Mackovski N, Azarpeykan S, Beard DJ, Coupland K, Patabendige A, Spratt NJ. Ultra-Short Duration Hypothermia Prevents Intracranial Pressure Elevation Following Ischaemic Stroke in Rats. Front Neurol 2021; 12:684353. [PMID: 34616350 PMCID: PMC8488292 DOI: 10.3389/fneur.2021.684353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/19/2021] [Indexed: 11/13/2022] Open
Abstract
There is a transient increase in intracranial pressure (ICP) 18–24 h after ischaemic stroke in rats, which is prevented by short-duration hypothermia using rapid cooling methods. Clinical trials of long-duration hypothermia have been limited by feasibility and associated complications, which may be avoided by short-duration cooling. Animal studies have cooled faster than is achievable in patients. We aimed to determine whether gradual cooling at a rate of 2°C/h to 33°C or 1°C/h to 34.5°C, with a 30 min duration at target temperatures, prevented ICP elevation and reduced infarct volume in rats. Transient middle cerebral artery occlusion was performed, followed by gradual cooling to target temperature. Hypothermia to 33°C prevented significant ICP elevation (hypothermia ΔICP = 1.56 ± 2.26 mmHg vs normothermia ΔICP = 8.93 ± 4.82 mmHg; p = 0.02) and reduced infarct volume (hypothermia = 46.4 ± 12.3 mm3 vs normothermia = 85.0 ± 17.5 mm3; p = 0.01). Hypothermia to 34.5°C did not significantly prevent ICP elevation or reduce infarct volume. We showed that gradual cooling to 33°C, at cooling rates achievable in patients, had the same ICP preventative effect as traditional rapid cooling methods. This suggests that this paradigm could be translated to prevent delayed ICP rise in stroke patients.
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Affiliation(s)
- Daniel Omileke
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Debbie Pepperall
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Steven W Bothwell
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Nikolce Mackovski
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Sara Azarpeykan
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Daniel J Beard
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Kirsten Coupland
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Adjanie Patabendige
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Neil J Spratt
- The School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton, NSW, Australia.,Department of Neurology, John Hunter Hospital, Hunter New England Local Health District, New Lambton, NSW, Australia
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5
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Beard DJ, Li Z, Schneider AM, Couch Y, Cipolla MJ, Buchan AM. Rapamycin Induces an eNOS (Endothelial Nitric Oxide Synthase) Dependent Increase in Brain Collateral Perfusion in Wistar and Spontaneously Hypertensive Rats. Stroke 2020; 51:2834-2843. [PMID: 32772681 DOI: 10.1161/strokeaha.120.029781] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND AND PURPOSE Rapamycin is a clinically approved mammalian target of rapamycin inhibitor that has been shown to be neuroprotective in animal models of stroke. However, the mechanism of rapamycin-induced neuroprotection is still being explored. Our aims were to determine if rapamycin improved leptomeningeal collateral perfusion, to determine if this is through eNOS (endothelial nitric oxide synthase)-mediated vessel dilation and to determine if rapamycin increases immediate postreperfusion blood flow. METHODS Wistar and spontaneously hypertensive rats (≈14 weeks old, n=22 and n=15, respectively) were subjected to ischemia by middle cerebral artery occlusion (90 and 120 minutes, respectively) with or without treatment with rapamycin at 30-minute poststroke. Changes in middle cerebral artery and collateral perfusion territories were measured by dual-site laser Doppler. Reactivity to rapamycin was studied using isolated and pressurized leptomeningeal anastomoses. Brain injury was measured histologically or with triphenyltetrazolium chloride staining. RESULTS In Wistar rats, rapamycin increased collateral perfusion (43±17%), increased reperfusion cerebral blood flow (16±8%) and significantly reduced infarct volume (35±6 versus 63±8 mm3, P<0.05). Rapamycin dilated leptomeningeal anastomoses by 80±9%, which was abolished by nitric oxide synthase inhibition. In spontaneously hypertensive rats, rapamycin increased collateral perfusion by 32±25%, reperfusion cerebral blood flow by 44±16%, without reducing acute infarct volume 2 hours postreperfusion. Reperfusion cerebral blood flow was a stronger predictor of brain damage than collateral perfusion in both Wistar and spontaneously hypertensive rats. CONCLUSIONS Rapamycin increased collateral perfusion and reperfusion cerebral blood flow in both Wistar and comorbid spontaneously hypertensive rats that appeared to be mediated by enhancing eNOS activation. These findings suggest that rapamycin may be an effective acute therapy for increasing collateral flow and as an adjunct therapy to thrombolysis or thrombectomy to improve reperfusion blood flow.
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Affiliation(s)
- Daniel J Beard
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, United Kingdom (D.J.B., A.M.S., Y.C., A.M.B.)
- School of Biomedical Science and Pharmacy, The University of Newcastle, Australia (D.J.B.)
| | - Zhaojin Li
- Department of Neurological Sciences, The University of Vermont, Burlington (Z.L., M.J.C.)
| | - Anna M Schneider
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, United Kingdom (D.J.B., A.M.S., Y.C., A.M.B.)
| | - Yvonne Couch
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, United Kingdom (D.J.B., A.M.S., Y.C., A.M.B.)
| | - Marilyn J Cipolla
- Department of Neurological Sciences, The University of Vermont, Burlington (Z.L., M.J.C.)
| | - Alastair M Buchan
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, United Kingdom (D.J.B., A.M.S., Y.C., A.M.B.)
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6
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Murtha LA, Beard DJ, Bourke JT, Pepperall D, McLeod DD, Spratt NJ. Intracranial Pressure Elevation 24 h after Ischemic Stroke in Aged Rats Is Prevented by Early, Short Hypothermia Treatment. Front Aging Neurosci 2016; 8:124. [PMID: 27303291 PMCID: PMC4882323 DOI: 10.3389/fnagi.2016.00124] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/13/2016] [Indexed: 11/13/2022] Open
Abstract
Stroke is predominantly a senescent disease, yet most preclinical studies investigate treatment in young animals. We recently demonstrated that short-duration hypothermia-treatment completely prevented the dramatic intracranial pressure (ICP) rise seen post-stroke in young rats. Here, our aim was to investigate whether a similar ICP rise occurs in aged rats and to determine whether short-duration hypothermia is an effective treatment in aged animals. Experimental middle cerebral artery occlusion (MCAo-3 h occlusion) was performed on male Wistar rats aged 19–20 months. At 1 h after stroke-onset, rats were randomized to 2.5 h hypothermia-treatment (32.5°C) or normothermia (37°C). ICP was monitored at baseline, for 3.5 h post-occlusion, and at 24 h post-stroke. Infarct and edema volumes were calculated from histology. Baseline pre-stroke ICP was 11.2 ± 3.3 mmHg across all animals. Twenty-four hours post-stroke, ICP was significantly higher in normothermic animals compared to hypothermia-treated animals (27.4 ± 18.2 mmHg vs. 8.0 ± 5.0 mmHg, p = 0.03). Infarct and edema volumes were not significantly different between groups. These data demonstrate ICP may also increase 24 h post-stroke in aged rats, and that short-duration hypothermia treatment has a profound and sustained preventative effect. These findings may have important implications for the use of hypothermia in clinical trials of aged stroke patients.
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Affiliation(s)
- Lucy A Murtha
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
| | - Daniel J Beard
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
| | - Julia T Bourke
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
| | - Debbie Pepperall
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
| | - Damian D McLeod
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
| | - Neil J Spratt
- Translational Stroke Research Laboratory, Faculty of Health and Medicine, School of Biomedical Sciences and Pharmacy, Hunter Medical Research Institute and The University of Newcastle Callaghan, NSW, Australia
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7
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Beard DJ, Logan CL, McLeod DD, Hood RJ, Pepperall D, Murtha LA, Spratt NJ. Ischemic penumbra as a trigger for intracranial pressure rise - A potential cause for collateral failure and infarct progression? J Cereb Blood Flow Metab 2016; 36:917-27. [PMID: 26759431 PMCID: PMC4853839 DOI: 10.1177/0271678x15625578] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/04/2015] [Indexed: 11/17/2022]
Abstract
We have recently shown that intracranial pressure (ICP) increases dramatically 24 h after minor intraluminal thread occlusion with reperfusion, independent of edema. Some of the largest ICP rises were observed in rats with the smallest final infarcts. A possible alternate mechanism for this ICP rise is an increase of cerebrospinal fluid (CSF) volume secondary to choroid plexus damage (a known complication of the intraluminal stroke model used). Alternatively, submaximal injury may be needed to induce ICP elevation. Therefore, we aimed to determine (a) if choroid plexus damage contributes to the ICP elevation, (b) if varying the patency of an important internal collateral supply to the middle cerebral artery (MCA), the anterior choroidal artery (AChA), produces different volumes of ischemic penumbra and (c) if presence of ischemic penumbra (submaximal injury) is associated with ICP elevation. We found (a) no association between choroid plexus damage and ICP elevation, (b) animals with a good internal collateral supply through the AChA during MCAo had significantly larger penumbra volumes and (c) ICP elevation at ≈24 h post-stroke only occurred in rats with submaximal injury, shown in two different stroke models. We conclude that active cellular processes within the ischemic penumbra may be required for edema-independent ICP elevation.
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Affiliation(s)
- Daniel J Beard
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Caitlin L Logan
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Damian D McLeod
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Rebecca J Hood
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Debbie Pepperall
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Lucy A Murtha
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Neil J Spratt
- School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia Hunter Medical Research Institute, New Lambton, New South Wales, Australia Department of Neurology, John Hunter Hospital, Hunter New England Local Health District, New South Wales, Australia
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8
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Ingberg E, Theodorsson E, Theodorsson A, Ström JO. Effects of high and low 17β-estradiol doses on focal cerebral ischemia in rats. Sci Rep 2016; 6:20228. [PMID: 26839007 PMCID: PMC4738304 DOI: 10.1038/srep20228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/23/2015] [Indexed: 12/19/2022] Open
Abstract
The majority of the numerous animal studies of the effects of estrogens on cerebral ischemia have reported neuroprotective results, but a few have shown increased damage. Differences in hormone administration methods, resulting in highly different 17β-estradiol levels, may explain the discrepancies in previously reported effects. The objective of the present study was to test the hypothesis that it is the delivered dose per se, and not the route and method of administration, that determines the effect, and that high doses are damaging while lower doses are protective. One hundred and twenty ovariectomized female Wistar rats (n = 40 per group) were randomized into three groups, subcutaneously administered different doses of 17β-estradiol and subjected to transient middle cerebral artery occlusion. The modified sticky tape test was performed after 24 h and the rats were subsequently sacrificed for infarct size measurements. In contrast to our hypothesis, a significant negative correlation between 17β-estradiol dose and infarct size was found (p = 0.018). Thus, no support was found for the hypothesis that 17β-estradiol can be both neuroprotective and neurotoxic merely depending on dose. In fact, on the contrary, the findings indicate that the higher the dose of 17β-estradiol, the smaller the infarct.
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Affiliation(s)
- Edvin Ingberg
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Annette Theodorsson
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Division of Neuroscience, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Neurosurgery, Anaesthetics, Operations and Specialty Surgery Center, Region Östergötland
| | - Jakob O Ström
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, Region Örebro Län, Örebro, Sweden.,School of Health and Medical Sciences, Örebro University, Örebro, Sweden
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9
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El Amki M, Clavier T, Perzo N, Bernard R, Guichet PO, Castel H. Hypothalamic, thalamic and hippocampal lesions in the mouse MCAO model: Potential involvement of deep cerebral arteries? J Neurosci Methods 2015. [PMID: 26213218 DOI: 10.1016/j.jneumeth.2015.07.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Intraluminal monofilament occlusion of the middle cerebral artery (MCAO) in mice is the most used rodent model to study the pathophysiology of stroke. However, this model often shows brain damage in regions not supplied by the MCA such as the hypothalamus, hippocampus and thalamus. Several studies have suggested some explanations on these localized infarcts. We aim to provide an alternative explanation which could allow each experimenter to better grasp the MCAO model. We propose that the MCA occlusion by the monofilament also occludes deep and small cerebral arteries arising directly from the internal carotid artery, proximally to the origin of MCA. Then, drawbacks and pitfalls of the MCAO model must be appreciated and the almost systematic risk of inducing lesions in some unwanted territories for neuroanatomical reasons, i.e. vascular connections between deep arteries and hypothalamic, thalamic and hippocampal areas in rodents has to be integrated.
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Affiliation(s)
- Mohamad El Amki
- Institut National de la Santé et de la Recherche Médicale (Inserm), U982, Rouen University, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Mont-Saint-Aignan, France.
| | - Thomas Clavier
- Institut National de la Santé et de la Recherche Médicale (Inserm), U982, Rouen University, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Mont-Saint-Aignan, France; Department of Anesthesiology and Critical Care, Rouen University Hospital, Rouen, France
| | - Nicolas Perzo
- Institut National de la Santé et de la Recherche Médicale (Inserm), U982, Rouen University, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Mont-Saint-Aignan, France
| | - René Bernard
- Department of Experimental Neurology, Charité University Medicine, Berlin, Germany
| | - Pierre-Olivier Guichet
- Institut National de la Santé et de la Recherche Médicale (Inserm), U982, Rouen University, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Mont-Saint-Aignan, France
| | - Hélène Castel
- Institut National de la Santé et de la Recherche Médicale (Inserm), U982, Rouen University, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Mont-Saint-Aignan, France
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10
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Beard DJ, McLeod DD, Logan CL, Murtha LA, Imtiaz MS, van Helden DF, Spratt NJ. Intracranial pressure elevation reduces flow through collateral vessels and the penetrating arterioles they supply. A possible explanation for 'collateral failure' and infarct expansion after ischemic stroke. J Cereb Blood Flow Metab 2015; 35:861-72. [PMID: 25669909 PMCID: PMC4420869 DOI: 10.1038/jcbfm.2015.2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/22/2014] [Accepted: 12/27/2014] [Indexed: 01/09/2023]
Abstract
Recent human imaging studies indicate that reduced blood flow through pial collateral vessels ('collateral failure') is associated with late infarct expansion despite stable arterial occlusion. The cause for 'collateral failure' is unknown. We recently showed that intracranial pressure (ICP) rises dramatically but transiently 24 hours after even minor experimental stroke. We hypothesized that ICP elevation would reduce collateral blood flow. First, we investigated the regulation of flow through collateral vessels and the penetrating arterioles arising from them during stroke reperfusion. Wistar rats were subjected to intraluminal middle cerebral artery (MCA) occlusion (MCAo). Individual pial collateral and associated penetrating arteriole blood flow was quantified using fluorescent microspheres. Baseline bidirectional flow changed to MCA-directed flow and increased by >450% immediately after MCAo. Collateral diameter changed minimally. Second, we determined the effect of ICP elevation on collateral and watershed penetrating arteriole flow. Intracranial pressure was artificially raised in stepwise increments during MCAo. The ICP increase was strongly correlated with collateral and penetrating arteriole flow reductions. Changes in collateral flow post-stroke appear to be primarily driven by the pressure drop across the collateral vessel, not vessel diameter. The ICP elevation reduces cerebral perfusion pressure and collateral flow, and is the possible explanation for 'collateral failure' in stroke-in-progression.
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Affiliation(s)
- Daniel J Beard
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia
| | - Damian D McLeod
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia
| | - Caitlin L Logan
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia
| | - Lucy A Murtha
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia
| | - Mohammad S Imtiaz
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia [2] Computational Cardiology Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Dirk F van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia
| | - Neil J Spratt
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia [2] Department of Neurology, John Hunter Hospital, Hunter New England Local Health District, New Lambton Heights, New South Wales, Australia
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Murtha LA, McLeod DD, Pepperall D, McCann SK, Beard DJ, Tomkins AJ, Holmes WM, McCabe C, Macrae IM, Spratt NJ. Intracranial pressure elevation after ischemic stroke in rats: cerebral edema is not the only cause, and short-duration mild hypothermia is a highly effective preventive therapy. J Cereb Blood Flow Metab 2015; 35:592-600. [PMID: 25515213 PMCID: PMC4420875 DOI: 10.1038/jcbfm.2014.230] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 01/25/2023]
Abstract
In both the human and animal literature, it has largely been assumed that edema is the primary cause of intracranial pressure (ICP) elevation after stroke and that more edema equates to higher ICP. We recently demonstrated a dramatic ICP elevation 24 hours after small ischemic strokes in rats, with minimal edema. This ICP elevation was completely prevented by short-duration moderate hypothermia soon after stroke. Here, our aims were to determine the importance of edema in ICP elevation after stroke and whether mild hypothermia could prevent the ICP rise. Experimental stroke was performed in rats. ICP was monitored and short-duration mild (35 °C) or moderate (32.5 °C) hypothermia, or normothermia (37 °C) was induced after stroke onset. Edema was measured in three studies, using wet-dry weight calculations, T2-weighted magnetic resonance imaging, or histology. ICP increased 24 hours after stroke onset in all normothermic animals. Short-duration mild or moderate hypothermia prevented this rise. No correlation was seen between ΔICP and edema or infarct volumes. Calculated rates of edema growth were orders of magnitude less than normal cerebrospinal fluid production rates. These data challenge current concepts and suggest that factors other than cerebral edema are the primary cause of the ICP elevation 24 hours after stroke onset.
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Affiliation(s)
- Lucy A Murtha
- 1] University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia [2] Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Damian D McLeod
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Debbie Pepperall
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Sarah K McCann
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Daniel J Beard
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Amelia J Tomkins
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Christopher McCabe
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Neil J Spratt
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
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12
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Tomkins AJ, Schleicher N, Murtha L, Kaps M, Levi CR, Nedelmann M, Spratt NJ. Platelet rich clots are resistant to lysis by thrombolytic therapy in a rat model of embolic stroke. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2015; 7:2. [PMID: 25657829 PMCID: PMC4318170 DOI: 10.1186/s13231-014-0014-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/22/2014] [Indexed: 11/21/2022]
Abstract
Background Early recanalization of occluded vessels in stroke is closely associated with improved clinical outcome. Microbubble-enhanced sonothrombolysis is a promising therapy to improve recanalization rates and reduce the time to recanalization. Testing any thrombolytic therapy requires a model of thromboembolic stroke, but to date these models have been highly variable with regards to clot stability. Here, we developed a model of thromboembolic stroke in rats with site-specific delivery of platelet-rich clots (PRC) to the main stem of the middle cerebral artery (MCA). This model was used in a subsequent study to test microbubble-enhanced sonothrombolysis. Methods In Study 1 we investigated spontaneous recanalization rates of PRC in vivo over 4 hours and measured infarct volumes at 24 hours. In Study 2 we investigated tPA-mediated thrombolysis and microbubble-enhanced sonothrombolysis in this model. Results Study 1 demonstrated stable occlusion out to 4 hours in 5 of 7 rats. Two rats spontaneously recanalized at 40 and 70 minutes post-embolism. Infarct volumes were not significantly different in recanalized rats, 43.93 ± 15.44% of the ischemic hemisphere, compared to 48.93 ± 3.9% in non-recanalized animals (p = 0.7). In Study 2, recanalization was not observed in any of the groups post-treatment. Conclusions Site specific delivery of platelet rich clots to the MCA origin resulted in high rates of MCA occlusion, low rates of spontaneous clot lysis and large infarction. These platelet rich clots were highly resistant to tPA with or without microbubble-enhanced sonothrombolysis. This resistance of platelet rich clots to enhanced thrombolysis may explain recanalization failures clinically and should be an impetus to better clot-type identification and alternative recanalization methods. Electronic supplementary material The online version of this article (doi:10.1186/s13231-014-0014-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amelia J Tomkins
- School of Biomedical Sciences & Pharmacy, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - Nadine Schleicher
- Heart and Brain Research Group, Justus-Liebig-University, Giessen and Kerckhoff Clinic, Bad Nauheim, Germany ; Department of Neurology, Justus-Liebig-University, Giessen, Germany ; Department of Cardiac Surgery, Kerckhoff Clinic, Bad Nauheim, Germany
| | - Lucy Murtha
- School of Biomedical Sciences & Pharmacy, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - Manfred Kaps
- Department of Neurology, Justus-Liebig-University, Giessen, Germany
| | - Christopher R Levi
- Hunter New England Local Health District, Newcastle, Australia ; School of Medicine and Public Health, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - Max Nedelmann
- Department of Neurology, Justus-Liebig-University, Giessen, Germany ; Sana Regio Klinkum, Pinneberg, Germany ; Department of Neurology, University Hospital Center Hamburg-Eppendorf, Hamburg, Germany
| | - Neil J Spratt
- School of Biomedical Sciences & Pharmacy, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia ; Hunter New England Local Health District, Newcastle, Australia
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