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Abdalkader M, Nguyen TN, Sahoo A, Qureshi MM, Ong CJ, Klein P, Miller MI, Mian AZ, Kaesmacher J, Mujanovic A, Hu W, Chen HS, Setty BN. Contrast Staining in Noninfarcted Tissue after Endovascular Treatment of Acute Ischemic Stroke. AJNR Am J Neuroradiol 2024; 45:701-707. [PMID: 38697792 PMCID: PMC11288587 DOI: 10.3174/ajnr.a8222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 02/03/2024] [Indexed: 05/05/2024]
Abstract
BACKGROUND AND PURPOSE Contrast staining is a common finding after endovascular treatment of acute ischemic stroke. It typically occurs in infarcted tissue and is considered an indicator of irreversible brain damage. Contrast staining in noninfarcted tissue has not been systematically investigated. We sought to assess the incidence, risk factors, and clinical significance of contrast staining in noninfarcted tissue after endovascular treatment. MATERIALS AND METHODS We conducted a retrospective review of consecutive patients who underwent endovascular treatment for anterior circulation large-vessel occlusion acute ischemic stroke. Contrast staining, defined as new hyperdensity on CT after endovascular treatment, was categorized as either contrast staining in infarcted tissue if the stained region demonstrated restricted diffusion on follow-up MR imaging or contrast staining in noninfarcted tissue if the stained region demonstrated no restricted diffusion. Baseline differences between patients with and without contrast staining in noninfarcted tissue were compared. Logistic regression was used to identify independent associations for contrast staining in noninfarcted tissue after endovascular treatment. RESULTS Among 194 patients who underwent endovascular treatment for large-vessel occlusion acute ischemic stroke and met the inclusion criteria, contrast staining in infarcted tissue was noted in 52/194 (26.8%) patients; contrast staining in noninfarcted tissue, in 26 (13.4%) patients. Both contrast staining in infarcted tissue and contrast staining in noninfarcted tissue were noted in 5.6% (11/194). Patients with contrast staining in noninfarcted tissue were found to have a higher likelihood of having an ASPECTS of 8-10, to be associated with contrast staining in infarcted tissue, and to achieve successful reperfusion compared with those without contrast staining in noninfarcted tissue. In contrast staining in noninfarcted tissue regions, the average attenuation was 40 HU, significantly lower than the contrast staining in infarcted tissue regions (53 HU). None of the patients with contrast staining in noninfarcted tissue had clinical worsening during their hospital stay. The median discharge mRS was significantly lower in patients with contrast staining in noninfarcted tissue than in those without (3 versus 4; P = .018). No independent predictors of contrast staining in noninfarcted tissue were found. CONCLUSIONS Contrast staining can be seen outside the infarcted tissue after endovascular treatment of acute ischemic stroke, likely attributable to the reversible disruption of the BBB in ischemic but not infarcted tissue. While generally benign, understanding its characteristics is important because it may mimic pathologic conditions such as infarcted tissue and cerebral edema.
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Affiliation(s)
- Mohamad Abdalkader
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Thanh N Nguyen
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
- Department of Neurology (T.N.N., C.J.O.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Anurag Sahoo
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Muhammad M Qureshi
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Charlene J Ong
- Department of Neurology (T.N.N., C.J.O.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
- Department of Neurology (C.J.O.), Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Piers Klein
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Matthew I Miller
- Department of Medicine (M.I.M.), Cambridge Health Alliance, Cambridge, Massachusetts
| | - Asim Z Mian
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
| | - Johannes Kaesmacher
- Institute of Diagnostic and Interventional Neuroradiology, Institute of Diagnostic, Interventional and Pediatric Radiology and Department of Neurology (J.K., A.M.), Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Adnan Mujanovic
- Institute of Diagnostic and Interventional Neuroradiology, Institute of Diagnostic, Interventional and Pediatric Radiology and Department of Neurology (J.K., A.M.), Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - Wei Hu
- Department of Neurology and Stroke Center (W.H.), Division of Life Sciences and Medicine, The First Affiliated Hospital of the University of Science and Technology of China, Hefei, Anhui, China
| | - Hui Sheng Chen
- Department of Neurology (H.S.C.), General Hospital of Northern Theater Command, Shenyang, China
| | - Bindu N Setty
- From the Department of Radiology (M.A., T.N.N., A.S., M.M.Q., P.K., A.Z.M., B.N.S.), Boston Medical Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
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Shimamura M, Yang Chang C, Hayashi H, Baba S, Yoshida S, Nakagami H. Impact of insufficient recovery of cerebral blood flow due to partial reperfusion on the pathophysiology of ischemic stroke in mice. Neurosci Lett 2023; 810:137370. [PMID: 37399972 DOI: 10.1016/j.neulet.2023.137370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/18/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Recent advances in endovascular treatment (EVT) dramatically changed the outcome of ischemic stroke, but partial reperfusion does not improve the outcome as well as no reperfusion. Although partial reperfusion is estimated to be more potential for therapeutic intervention than permanent occlusion due to some blood supply, their pathophysiological difference is still unknown. To answer the question, we analyzed the difference in mice, which were exposed to distal middle cerebral artery occlusion with 14-min common carotid artery (CCA) occlusion (partial reperfusion) or permanent CCA occlusion (no reperfusion). Although the final infarct volume was same between permanent and partial reperfusion, Fluoro-jade C staining showed that neurodegeneration was inhibited both in the severe and moderate ischemic region 3 h after partial reperfusion. Also, partial reperfusion increased the number of TUNEL-positive cells only in the severe ischemic region. IgG extravasation was suppressed at 24 h only in the moderate ischemic region in partial reperfusion. Injected FITC-dextran was observed in the brain parenchyma with BBB leakage at 24 h in partial reperfusion, but not in permanent occlusion. The expression of il1β and il6 mRNA was inhibited in the severe ischemic region. Thus, partial reperfusion showed region-dependent favorable pathophysiology, such as delayed neurodegeneration, suppressed BBB destruction and inflammation, and potential for drug delivery, when compared to permanent occlusion. Further studies on the molecular differences and effectiveness of drugs will shed light on the development of novel treatments for partial reperfusion in ischemic stroke.
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Affiliation(s)
- Munehisa Shimamura
- Department of Gene & Stem Cell Regenerative Therapy, Osaka University Graduate School of Medicine, 565-0871, Japan; Department of Neurology, Osaka University Graduate School of Medicine, Japan.
| | - Chin Yang Chang
- Department of Gene & Stem Cell Regenerative Therapy, Osaka University Graduate School of Medicine, 565-0871, Japan
| | - Hiroki Hayashi
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, 565-0871, Japan
| | - Satoshi Baba
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, 565-0871, Japan; Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Japan
| | - Shota Yoshida
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, 565-0871, Japan; Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Japan
| | - Hironori Nakagami
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, 565-0871, Japan
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Wakayama K, Shimamura M, Yoshida S, Hayashi H, Ju N, Nakagami H, Morishita R. Prevention of vascular dementia via immunotherapeutic blockade of renin-angiotensin system in a rat model. Brain Res 2021; 1772:147667. [PMID: 34587500 DOI: 10.1016/j.brainres.2021.147667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 12/11/2022]
Abstract
INTRODUCTION As several clinical trials have revealed that angiotensin-converting enzyme inhibitors and angiotensin II (Ang II) receptor blockers may be efficient in treating vascular dementia (VaD), the long-acting blockade of the renin-angiotensin system (RAS) would be useful considering the poor adherence of antihypertensive drugs. Accordingly, we continuously blocked RAS via vaccination and examined the effectiveness of the VaD model in rats. METHODS Male Wistar rats were exposed to two-vessel occlusions (2VO) after three injections of Ang II peptide vaccine. The effects of the vaccine were evaluated in the novel object recognition test, brain RAS components, and markers for oligodendrocytes. RESULTS In the vaccinated rats, anti-Ang II antibody titer level was increased in serum until Day 168, but not in cerebral parenchyma. Vaccinated rats showed better object recognition memory with inhibited demyelination in the corpus callosum and activation of astrocytes and microglia. Also, levels of BrdU/GSTπ-positive cells and the phosphorylation of cAMP response element binding protein was increased in vaccinated rats, indicating that the differentiation of oligodendrocyte progenitor cells to mature oligodendrocytes was accelerated. Vaccinated rats showed increased expression of fibroblast growth factor-2 (FGF2), which was observed in endothelial cells. Angiotensinogen mRNA was decreased at 7 days after 2VO but increased at 14 and 28 days. CONCLUSION Ang II vaccine might have promoted oligodendrocyte differentiation and inhibited astrocytic and microglial activation by stimulating FGF2 signaling in the endothelial cells-oligodendrocyte/astrocyte/microglia coupling. These data indicate the feasibility of Ang II vaccine for preventing progression of vascular dementia.
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Affiliation(s)
- Kouji Wakayama
- Department of Advanced Clinical Science and Therapeutics, Graduate School of Medicine, The University of Tokyo, Japan
| | - Munehisa Shimamura
- Department of Neurology, Osaka University, Graduate School of Medicine, Japan; Department of Health Development and Medicine, Osaka University, Graduate School of Medicine, Japan.
| | - Shota Yoshida
- Department of Health Development and Medicine, Osaka University, Graduate School of Medicine, Japan
| | - Hiroki Hayashi
- Department of Health Development and Medicine, Osaka University, Graduate School of Medicine, Japan
| | - Nan Ju
- Department of Health Development and Medicine, Osaka University, Graduate School of Medicine, Japan
| | - Hironori Nakagami
- Department of Health Development and Medicine, Osaka University, Graduate School of Medicine, Japan
| | - Ryuichi Morishita
- Department of Clinical Gene Therapy, Osaka University, Graduate School of Medicine, Japan.
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Hou W, Jiang Y, Xie G, Zhao L, Zhao F, Zhang X, Sun SK, Yu C, Pan J. Biocompatible BSA-MnO 2 nanoparticles for in vivo timely permeability imaging of blood-brain barrier and prediction of hemorrhage transformation in acute ischemic stroke. NANOSCALE 2021; 13:8531-8542. [PMID: 33908561 DOI: 10.1039/d1nr02015c] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hemorrhage transformation (HT) is a frequent but maybe fatal complication following acute ischemic stroke due to severe damage of the blood-brain barrier (BBB). Quantitative BBB permeability imaging is a promising method to predict HT in stroke patients for a favorable prognosis. However, clinical gadolinium chelate-based magnetic resonance (MR) imaging of the stroke suffers from a relatively low sensitivity and potential side effects of nephrogenic systemic fibrosis and intracranial gadolinium deposition. Herein, BSA-MnO2 nanoparticles (BM NPs) fabricated by a facile disinfection-mimic method were employed for the permeability imaging of BBB in the stroke for the first time. The BM NPs showed a high T1 relaxivity (r1 = 5.9 mM-1 s-1), remarkable MR imaging ability, and good biocompatibility, allowing the noninvasive timely visualization of BBB permeability in the model rats of middle cerebral artery occlusion (MCAO). Furthermore, increased peak intensity, extended imaging duration, and expanded imaging region indicated by BM NPs in MR imaging showed a good prediction for the onset of HT in MCAO rats. Therefore, BM NPs hold an attractive potential to be an alternative biocompatible MR contrast agent for the noninvasive BBB permeability imaging in vivo, benefiting the fundamental research of diverse neurological disorders and the clinical treatment for stroke patients.
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Affiliation(s)
- Wenjing Hou
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin 300052, China.
| | - Yingzong Jiang
- School of Medical Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Guangchao Xie
- School of Medical Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Lu Zhao
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin 300052, China.
| | - Fangshi Zhao
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin 300052, China.
| | - Xuejun Zhang
- School of Medical Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Shao-Kai Sun
- School of Medical Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Chunshui Yu
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin 300052, China. and School of Medical Imaging, Tianjin Medical University, Tianjin 300203, China.
| | - Jinbin Pan
- Department of Radiology, Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin 300052, China.
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Kikuchi T, Fukuta T, Agato Y, Yanagida Y, Ishii T, Koide H, Shimizu K, Oku N, Asai T. Suppression of Cerebral Ischemia/Reperfusion Injury by Efficient Release of Encapsulated Ifenprodil From Liposomes Under Weakly Acidic pH Conditions. J Pharm Sci 2019; 108:3823-3830. [PMID: 31520645 DOI: 10.1016/j.xphs.2019.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/29/2019] [Accepted: 09/06/2019] [Indexed: 01/19/2023]
Abstract
Although N-methyl-d-aspartate receptor antagonists are hopeful therapeutic agents against cerebral ischemia/reperfusion (I/R) injury, effective approaches are needed to allow such agents to pass through the blood-brain barrier, thus increasing bioavailability of the antagonists to realize secure treatment. We previously demonstrated the usefulness of liposomal delivery of neuroprotectants via spaces between the disrupted blood-brain barrier induced after cerebral I/R. In the present study, a liposomal formulation of an N-methyl-d-aspartate receptor antagonist, ifenprodil, was newly designed; and the potential of liposomal ifenprodil was evaluated in transient middle cerebral artery occlusion rats. Ifenprodil was encapsulated into liposomes by a remote loading method using pH gradient between internal and external water phases of liposomes, focusing on differences of its solubility in water depending on pH. The encapsulated ifenprodil could be quickly released from the liposomes in vitro under a weakly acidic pH condition, which is a distinctive condition after cerebral I/R. Liposomal ifenprodil treatment significantly alleviated I/R-induced increase in permeability of the BBB by inhibiting superoxide anion production, resulting in ameliorating ischemic brain damage. Taken together, these results suggest that Ifen-Lip could become a hopeful neuroprotectant for cerebral I/R injury via efficient release of the encapsulated ifenprodil under weakly acidic pH conditions.
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Affiliation(s)
- Takashi Kikuchi
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Tatsuya Fukuta
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Yurika Agato
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Yosuke Yanagida
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Takayuki Ishii
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Hiroyuki Koide
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Kosuke Shimizu
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Naoto Oku
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan; Faculty of Pharma-Science, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605 Japan
| | - Tomohiro Asai
- Department of Medical Biochemistry, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
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Gandhi R, Tsoumpas C. Preclinical Imaging Biomarkers for Postischaemic Neurovascular Remodelling. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:3128529. [PMID: 30863220 PMCID: PMC6378027 DOI: 10.1155/2019/3128529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/22/2018] [Accepted: 12/04/2018] [Indexed: 11/30/2022]
Abstract
In the pursuit of understanding the pathological alterations that underlie ischaemic injuries, such as vascular remodelling and reorganisation, there is a need for recognising the capabilities and limitations of in vivo imaging techniques. Thus, this review presents contemporary published research of imaging modalities that have been implemented to study postischaemic neurovascular changes in small animals. A comparison of the technical aspects of the various imaging tools is included to set the framework for identifying the most appropriate methods to observe postischaemic neurovascular remodelling. A systematic search of the PubMed® and Elsevier's Scopus databases identified studies that were conducted between 2008 and 2018 to explore postischaemic neurovascular remodelling in small animal models. Thirty-five relevant in vivo imaging studies are included, of which most made use of magnetic resonance imaging or positron emission tomography, whilst various optical modalities were also utilised. Notably, there is an increasing trend of using multimodal imaging to exploit the most beneficial properties of each imaging technique to elucidate different aspects of neurovascular remodelling. Nevertheless, there is still scope for further utilising noninvasive imaging tools such as contrast agents or radiotracers, which will have the ability to monitor neurovascular changes particularly during restorative therapy. This will facilitate more successful utility of the clinical imaging techniques in the interpretation of neurovascular reorganisation over time.
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Affiliation(s)
- Richa Gandhi
- Department of Biomedical Imaging Science, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9NL, West Yorkshire, UK
| | - Charalampos Tsoumpas
- Department of Biomedical Imaging Science, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9NL, West Yorkshire, UK
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Jiang X, Andjelkovic AV, Zhu L, Yang T, Bennett MVL, Chen J, Keep RF, Shi Y. Blood-brain barrier dysfunction and recovery after ischemic stroke. Prog Neurobiol 2017; 163-164:144-171. [PMID: 28987927 DOI: 10.1016/j.pneurobio.2017.10.001] [Citation(s) in RCA: 557] [Impact Index Per Article: 79.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 05/30/2017] [Accepted: 10/02/2017] [Indexed: 01/06/2023]
Abstract
The blood-brain barrier (BBB) plays a vital role in regulating the trafficking of fluid, solutes and cells at the blood-brain interface and maintaining the homeostatic microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the BBB can be disrupted, followed by the extravasation of blood components into the brain and compromise of normal neuronal function. This article reviews recent advances in our knowledge of the mechanisms underlying BBB dysfunction and recovery after ischemic stroke. CNS cells in the neurovascular unit, as well as blood-borne peripheral cells constantly modulate the BBB and influence its breakdown and repair after ischemic stroke. The involvement of stroke risk factors and comorbid conditions further complicate the pathogenesis of neurovascular injury by predisposing the BBB to anatomical and functional changes that can exacerbate BBB dysfunction. Emphasis is also given to the process of long-term structural and functional restoration of the BBB after ischemic injury. With the development of novel research tools, future research on the BBB is likely to reveal promising potential therapeutic targets for protecting the BBB and improving patient outcome after ischemic stroke.
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Affiliation(s)
- Xiaoyan Jiang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | | | - Ling Zhu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Tuo Yang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Michael V L Bennett
- State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jun Chen
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Yejie Shi
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Sifat AE, Vaidya B, Abbruscato TJ. Blood-Brain Barrier Protection as a Therapeutic Strategy for Acute Ischemic Stroke. AAPS JOURNAL 2017; 19:957-972. [PMID: 28484963 DOI: 10.1208/s12248-017-0091-7] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/18/2017] [Indexed: 02/07/2023]
Abstract
The blood-brain barrier (BBB) is a vital component of the neurovascular unit (NVU) containing tight junctional (TJ) proteins and different ion and nutrient transporters which maintain normal brain physiology. BBB disruption is a major pathological hallmark in the course of ischemic stroke which is regulated by the actions of different factors working at different stages of cerebral ischemia including matrix metalloproteinases (MMPs), inflammatory modulators, vesicular trafficking, oxidative pathways, and junctional-cytoskeletal interactions. These components interact further to disrupt maintenance of both the paracellular and transport barriers of the central nervous system (CNS) to worsen ischemic brain injury and the propensity for hemorrhagic transformation (HT) associated with injury and/or thrombolytic therapy with tissue-type plasminogen activator (tPA). We propose that these complex molecular pathways should be evaluated further so that they could be targeted alone or in combination to protect the BBB during cerebral ischemia. These types of novel interventions should be guided by advanced imaging techniques for better diagnosis of BBB damage which may exert significant therapeutic benefit including the extension of therapeutic window of tPA. This review will focus on the different stages and mechanisms of BBB damage in acute ischemic stroke and novel therapeutic strategies to target those pathways for better therapeutic outcome in stroke.
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Affiliation(s)
- Ali Ehsan Sifat
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter, Amarillo, Texas, 79106, USA
| | - Bhuvaneshwar Vaidya
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter, Amarillo, Texas, 79106, USA
| | - Thomas J Abbruscato
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter, Amarillo, Texas, 79106, USA.
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Shiraishi K, Wang Z, Kokuryo D, Aoki I, Yokoyama M. A polymeric micelle magnetic resonance imaging (MRI) contrast agent reveals blood–brain barrier (BBB) permeability for macromolecules in cerebral ischemia-reperfusion injury. J Control Release 2017; 253:165-171. [DOI: 10.1016/j.jconrel.2017.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 02/17/2017] [Accepted: 03/11/2017] [Indexed: 01/10/2023]
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Li W, Watts L, Long J, Zhou W, Shen Q, Jiang Z, Li Y, Duong TQ. Spatiotemporal changes in blood-brain barrier permeability, cerebral blood flow, T2 and diffusion following mild traumatic brain injury. Brain Res 2016; 1646:53-61. [PMID: 27208495 DOI: 10.1016/j.brainres.2016.05.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/12/2016] [Accepted: 05/18/2016] [Indexed: 12/21/2022]
Abstract
The blood-brain barrier (BBB) can be impaired following traumatic brain injury (TBI), however the spatiotemporal dynamics of BBB leakage remain incompletely understood. In this study, we evaluated the spatiotemporal evolution of BBB permeability using dynamic contrast-enhanced MRI and measured the volume transfer coefficient (K(trans)), a quantitative measure of contrast agent leakage across the blood and extravascular compartment. Measurements were made in a controlled cortical impact (CCI) model of mild TBI in rats from 1h to 7 days following TBI. The results were compared with cerebral blood flow, T2 and diffusion MRI from the same animal. Spatially, K(trans) changes were localized to superficial cortical layers within a 1mm thickness, which was dramatically different from the changes in cerebral blood flow, T2 and diffusion, which were localized to not only the superficial layers but also to brain regions up to 2.2mm from the cortical surface. Temporally, K(trans) changes peaked at day 3, similar to CBF and ADC changes, but differed from T2 and FA, whose changes peaked on day 2. The pattern of superficial cortical layer localization of K(trans) was consistent with patterns revealed by Evans Blue extravasation. Collectively, these results suggest that BBB disruption, edema formation, blood flow disturbance and diffusion changes are related to different components of the mechanical impact, and may play different roles in determining injury progression and tissue fate processes following TBI.
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Affiliation(s)
- Wei Li
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Lora Watts
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Neurology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Justin Long
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Wei Zhou
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Zhao Jiang
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Yunxia Li
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, TX 78229, USA.
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Achyut BR, Shankar A, Iskander ASM, Ara R, Knight RA, Scicli AG, Arbab AS. Chimeric Mouse model to track the migration of bone marrow derived cells in glioblastoma following anti-angiogenic treatments. Cancer Biol Ther 2016; 17:280-90. [PMID: 26797476 DOI: 10.1080/15384047.2016.1139243] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Bone marrow derived cells (BMDCs) have been shown to contribute in the tumor development. In vivo animal models to investigate the role of BMDCs in tumor development are poorly explored. We established a novel chimeric mouse model using as low as 5 × 10(6) GFP+ BM cells in athymic nude mice, which resulted in >70% engraftment within 14 d. In addition, chimera was established in NOD-SCID mice, which displayed >70% with in 28 d. Since anti-angiogenic therapies (AAT) were used as an adjuvant against VEGF-VEGFR pathway to normalize blood vessels in glioblastoma (GBM), which resulted into marked hypoxia and recruited BMDCs to the tumor microenvironment (TME). We exploited chimeric mice in athymic nude background to develop orthotopic U251 tumor and tested receptor tyrosine kinase inhibitors and CXCR4 antagonist against GBM. We were able to track GFP+ BMDCs in the tumor brain using highly sensitive multispectral optical imaging instrument. Increased tumor growth associated with the infiltration of GFP+ BMDCs acquiring suppressive myeloid and endothelial phenotypes was seen in TME following treatments. Immunofluorescence study showed GFP+ cells accumulated at the site of VEGF, SDF1 and PDGF expression, and at the periphery of the tumors following treatments. In conclusion, we developed a preclinical chimeric model of GBM and phenotypes of tumor infiltrated BMDCs were investigated in context of AATs. Chimeric mouse model could be used to study detailed cellular and molecular mechanisms of interaction of BMDCs and TME in cancer.
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Affiliation(s)
- B R Achyut
- a Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University , Augusta , GA , USA
| | - Adarsh Shankar
- a Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University , Augusta , GA , USA
| | - A S M Iskander
- a Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University , Augusta , GA , USA
| | - Roxan Ara
- a Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University , Augusta , GA , USA
| | | | - Alfonso G Scicli
- c Cellular and Molecular Imaging Laboratory, Henry Ford Health System , Detroit , MI , USA
| | - Ali S Arbab
- a Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University , Augusta , GA , USA
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12
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Kassner A, Merali Z. Assessment of Blood–Brain Barrier Disruption in Stroke. Stroke 2015; 46:3310-5. [DOI: 10.1161/strokeaha.115.008861] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/03/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Andrea Kassner
- From the Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (A.K., Z.M.); and Division of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario, Canada (A.K., Z.M.)
| | - Zamir Merali
- From the Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (A.K., Z.M.); and Division of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario, Canada (A.K., Z.M.)
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Ng KF, Anderson S, Mayo P, Aung HH, Walton JH, Rutledge JC. Characterizing blood-brain barrier perturbations after exposure to human triglyceride-rich lipoprotein lipolysis products using MRI in a rat model. Magn Reson Med 2015; 76:1246-51. [PMID: 26485349 PMCID: PMC4838551 DOI: 10.1002/mrm.25985] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/11/2015] [Accepted: 08/21/2015] [Indexed: 12/11/2022]
Abstract
PURPOSE Previous studies indicated hyperlipidemia may be a risk factor for Alzheimer's disease, but the contributions of postprandial triglyceride-rich lipoprotein (TGRL) are not known. In this study, changes in blood-brain barrier diffusional transport following exposure to human TGRL lipolysis products were studied using MRI in a rat model. METHODS Male Sprague-Dawley rats (∼180-250 g) received an i.v. injection of lipoprotein lipase (LpL)-hydrolyzed TGRL (n = 8, plasma concentration ≈ 150 mg human TGRL/dL). Controls received i.v. injection of either saline (n = 6) or LpL only (n = 6). The (1) H longitudinal relaxation rate R1 = 1/T1 was measured over 18 min using a rapid-acquired refocus-echo (RARE) sequence after each of three injections of the contrast agent Gd-DTPA. Patlak plots were generated for each pixel yielding blood-to-brain transfer coefficients, Ki , chosen for best fit to impermeable, uni-directional influx or bi-directional flux models using the F-test. RESULTS Analysis from a 2-mm slice, 2-mm rostral to the bregma showed a 275% increase of mean Ki during the first 20 min after infusion of human TGRL lipolysis product that differed significantly compared with saline and LpL controls. This difference disappeared by 40 min mark. CONCLUSION These results suggest human TGRL lipolysis products can lead to a transient increase in rat BBB permeability. Magn Reson Med 76:1246-1251, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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Affiliation(s)
- Kit Fai Ng
- School of Medicine, Division of Cardiovascular Medicine, University of California, Davis, California, USA
| | - Steve Anderson
- School of Medicine, Department of Physiology and Membrane Biology, University of California, Davis, California, USA
| | - Patrice Mayo
- School of Medicine, Division of Cardiovascular Medicine, University of California, Davis, California, USA
| | - Hnin Hnin Aung
- School of Medicine, Division of Cardiovascular Medicine, University of California, Davis, California, USA
| | - Jeffrey H Walton
- NMR Facility and Biomedical Engineering Graduate Group, University of California, Davis, California, USA
| | - John C Rutledge
- School of Medicine, Division of Cardiovascular Medicine, University of California, Davis, California, USA.
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14
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Kim T, Shin W, Kim SG. Fast magnetization transfer and apparent T1 imaging using a short saturation pulse with and without inversion preparation. Magn Reson Med 2015; 71:1264-71. [PMID: 23605886 DOI: 10.1002/mrm.24756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE Measurements of magnetization transfer (MT) metrics, such as the steady-state (SS) MT ratio and apparent longitudinal relaxation rate require multiple MT irradiation durations and a long experimental time. To overcome these problems, we propose a novel method using a short MT off-resonance pulse with and without on-resonance inversion preparation pulse. THEORY AND METHODS Computer simulations were performed to examine the accuracy of the proposed method and to find the optimal off-resonance irradiation pulse duration (Tirad) and power level (ω1). Our approach, with echo planar imaging data acquisition, was applied to animals at 9.4 T and humans at 3 T with ω1/2π = 100 Hz and 177 Hz, respectively. Steady-state MT ratio and relaxation rate were obtained from a pair of MT images at a Tirad, with and without inversion. RESULTS For Tirad ≥ 0.4 s, steady-state MT ratio, and relaxation rate measured at any single Tirad agreed well with those of the conventional fitting method that uses multiple Tirad. Our simulation indicates that a higher ω1 can use a shorter Tirad. CONCLUSION Steady-state MT ratio and relaxation rate can be determined from MT data with only one, short Tirad by incorporation of an inversion prepulse. This MT imaging approach is simple, fast, and easily implementable.
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Affiliation(s)
- Tae Kim
- Department of Radiology, Neuroimaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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15
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Achyut BR, Shankar A, Iskander ASM, Ara R, Angara K, Zeng P, Knight RA, Scicli AG, Arbab AS. Bone marrow derived myeloid cells orchestrate antiangiogenic resistance in glioblastoma through coordinated molecular networks. Cancer Lett 2015; 369:416-26. [PMID: 26404753 DOI: 10.1016/j.canlet.2015.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/29/2015] [Accepted: 09/09/2015] [Indexed: 12/29/2022]
Abstract
Glioblastoma (GBM) is a hypervascular and malignant form of brain tumors. Anti-angiogenic therapies (AAT) were used as an adjuvant against VEGF-VEGFR pathway to normalize blood vessels in clinical and preclinical studies, which resulted into marked hypoxia and recruited bone marrow derived cells (BMDCs) to the tumor microenvironment (TME). In vivo animal models to track BMDCs and investigate molecular mechanisms in AAT resistance are rare. We exploited recently established chimeric mouse to develop orthotopic U251 tumor, which uses as low as 5 × 10(6) GFP+ BM cells in athymic nude mice and engrafted >70% GFP+ cells within 14 days. Our unpublished data and published studies have indicated the involvement of immunosuppressive myeloid cells in therapeutic resistance in glioma. Similarly, in the present study, vatalanib significantly increased CD68+ myeloid cells, and CD133+, CD34+ and Tie2+ endothelial cell signatures. Therefore, we tested inhibition of CSF1R+ myeloid cells using GW2580 that reduced tumor growth by decreasing myeloid (Gr1+ CD11b+ and F4/80+) and angiogenic (CD202b+ and VEGFR2+) cell signatures in TME. CSF1R blockade significantly decreased inflammatory, proangiogenic and immunosuppressive molecular signatures compared to vehicle, vatalanib or combination. TCK1 or CXCL7, a potent chemoattractant and activator of neutrophils, was observed as most significantly decreased cytokine in CSF1R blockade. ERK MAPK pathway was involved in cytokine network regulation. In conclusion, present study confirmed the contribution of myeloid cells in GBM development and therapeutic resistance using chimeric mouse model. We identified novel molecular networks including CXCL7 chemokine as a promising target for future studies. Nonetheless, survival studies are required to assess the beneficial effect of CSF1R blockade.
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Affiliation(s)
- B R Achyut
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | - Adarsh Shankar
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | - A S M Iskander
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | - Roxan Ara
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | - Kartik Angara
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | - Peng Zeng
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA
| | | | - Alfonso G Scicli
- Cellular and Molecular Imaging Laboratory, Henry Ford Health System, Detroit, MI, USA
| | - Ali S Arbab
- Tumor Angiogenesis Laboratory, Biochemistry and Molecular Biology, Cancer Center, Georgia Regents University, Augusta, GA, USA.
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Abstract
The blood-brain barrier (BBB) is a microvascular unit which selectively regulates the permeability of drugs to the brain. With the rise in CNS drug targets and diseases, there is a need to be able to accurately predict a priori which compounds in a company database should be pursued for favorable properties. In this review, we will explore the different computational tools available today, as well as underpin these to the experimental methods used to determine BBB permeability. These include in vitro models and the in vivo models that yield the dataset we use to generate predictive models. Understanding of how these models were experimentally derived determines our accurate and predicted use for determining a balance between activity and BBB distribution.
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Walton JH, Ng KF, Anderson SE, Rutledge JC. MRI measurement of blood-brain barrier transport with a rapid acquisition refocused echo (RARE) method. Biochem Biophys Res Commun 2015; 463:479-82. [PMID: 25998382 DOI: 10.1016/j.bbrc.2015.05.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/10/2015] [Indexed: 10/23/2022]
Abstract
Dynamic Contrast Enhanced (DCE) MRI is increasingly being used to assess changes in capillary permeability. Most quantitative techniques used to measure capillary permeability are based on the Fick equation that requires measurement of signal reflecting both plasma and tissue concentrations of the solute being tested. To date, most Magnetic Resonance Imaging (MRI) methods for acquiring appropriate data quickly rely on gradient recalled echo (GRE) type acquisitions, which work well in clinical low field settings. However, acquiring this type of data on high field small animal preclinical MRIs is problematic due to geometrical distortions from susceptibility mismatch. This problem can be exacerbated when using small animal models to measure blood brain barrier (BBB) permeability, where precise sampling from the superior sagittal sinus (SSS) is commonly used to determine the plasma concentration of the contrast agent. Here we present results demonstrating that a standard saturation recovery rapid acquisition refocused echo (RARE) method is capable of acquiring T1 maps with good spatial and temporal resolution for Patlak analysis (Patlak, 1983) to assess changes in BBB Gd-DTPA permeability following middle cerebral artery occlusion with reperfusion in the rat. This method limits known problems with magnetic susceptibility mismatch and may thus allow greater accuracy in BBB permeability measurement in small animals.
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Affiliation(s)
- Jeffrey H Walton
- NMR Facility and Biomedical Engineering Graduate Group, University of California, Davis, USA.
| | - Kit Fai Ng
- Division of Cardiovascular Medicine, University of California, Davis, USA
| | - Steven E Anderson
- Department of Physiology and Membrane Biology, University of California, Davis, USA
| | - John C Rutledge
- Division of Cardiovascular Medicine, University of California, Davis, USA
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18
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Chodobski A, Ghersi-Egea JF, Nicholson C, Nagaraja TN, Szmydynger-Chodobska J. The quest for a better insight into physiology of fluids and barriers of the brain: the exemplary career of Joseph D. Fenstermacher. Fluids Barriers CNS 2015; 12:1. [PMID: 25745556 PMCID: PMC4350980 DOI: 10.1186/2045-8118-12-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 12/18/2014] [Indexed: 12/27/2022] Open
Abstract
In June 2014 Dr. Joseph D. Fenstermacher celebrated his 80th birthday, which was honored by the symposium held in New London, NH, USA. This review discusses Fenstermacher's contribution to the field of fluids and barriers of the CNS. Specifically, his fundamental work on diffusion of molecules within the brain extracellular space and the research on properties of the blood-brain barrier in health and disease are described. Fenstermacher's early research on cerebrospinal fluid dynamics and the regulation of cerebral blood flow is also reviewed, followed by the discussion of his more recent work involving the use of magnetic resonance imaging.
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Affiliation(s)
- Adam Chodobski
- Department of Emergency Medicine, Neurotrauma and Brain Barriers Research Laboratory, The Warren Alpert Medical School of Brown University, Coro Center West, Room 112, 1 Hoppin Street, Providence, RI 02903 USA
| | - Jean-François Ghersi-Egea
- Blood-Brain Interface Group, Oncoflam Team and BIP Platform INSERM U 1028, CNRS UMR5292 Lyon Neuroscience Research Center, Faculté de Médecine RTH Laennec, Rue Guillaume Paradin, Cedex 08, 69372 Lyon, France
| | - Charles Nicholson
- Department of Neuroscience and Physiology, NYU School of Medicine, MSB 460, 550 First Avenue, New York, NY 10016 USA
| | - Tavarekere N Nagaraja
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd., Detroit, MI 48202-2689 USA
| | - Joanna Szmydynger-Chodobska
- Department of Emergency Medicine, Neurotrauma and Brain Barriers Research Laboratory, The Warren Alpert Medical School of Brown University, Coro Center West, Room 112, 1 Hoppin Street, Providence, RI 02903 USA
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Nagaraja TN, Keenan KA, Aryal MP, Ewing JR, Gopinath S, Nadig VS, Shashikumar S, Knight RA. Extravasation into brain and subsequent spread beyond the ischemic core of a magnetic resonance contrast agent following a step-down infusion protocol in acute cerebral ischemia. Fluids Barriers CNS 2014; 11:21. [PMID: 25276343 PMCID: PMC4177725 DOI: 10.1186/2045-8118-11-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/19/2014] [Indexed: 12/02/2022] Open
Abstract
Background Limiting expansion of the ischemic core lesion by reinstating blood flow and protecting the penumbral cells is a priority in acute stroke treatment. However, at present, methods are not available for effective drug delivery to the ischemic penumbra. To address these issues this study compared the extravasation and subsequent interstitial spread of a magnetic resonance contrast agent (MRCA) beyond the ischemic core into the surrounding brain in a rat model of ischemia-reperfusion for bolus injection and step-down infusion (SDI) protocols. Methods Male Wistar rats underwent middle cerebral artery (MCA) occlusion for 3 h followed by reperfusion. Perfusion-diffusion mismatched regions indicating the extent of spread were identified by measuring cerebral blood flow (CBF) deficits by arterial spin-labeled magnetic resonance imaging and the extent of the ischemic core by mapping the apparent diffusion coefficient (ADC) of water with diffusion-weighted imaging. Vascular injury was assessed via MRCA, gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) penetration, by Look-Locker T1-weighted MR imaging after either a bolus injection (n = 8) or SDI (n = 6). Spatial and temporal expansion of the MRCA front during a 25 min imaging period was measured from images obtained at 2.5 min intervals. Results The mean ADC lesion was 20 ± 7% of the hemispheric area whereas the CBF deficit area was 60 ± 16%, with the difference between the areas suggesting the possible presence of a penumbra. The bolus injection led to MRCA enhancement with an area that initially spread into the ischemic core and then diminished over time. The SDI produced a gradual increase in the area of MRCA enhancement that slowly enlarged to occupy the core, eventually expanded beyond it into the surrounding tissue and then plateaued. The integrated area from SDI extravasation was significantly larger than that for the bolus (p = 0.03). The total number of pixels covered by the SDI at its maximum was significantly larger than the pixels covered by bolus maximum (p = 0.05). Conclusions These results demonstrate that the SDI protocol resulted in a spread of the MRCA beyond the ischemic core. Whether plasma-borne acute stroke therapeutics can be delivered to the ischemic penumbra in a similar way needs to be investigated.
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Affiliation(s)
- Tavarekere N Nagaraja
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
| | - Kelly A Keenan
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
| | - Madhava P Aryal
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA ; Present address: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - James R Ewing
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA ; Department of Physics, Oakland University, Rochester, MI, USA ; Department of Neurology, Wayne State University, Detroit, MI, USA
| | - Saarang Gopinath
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
| | - Varun S Nadig
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
| | - Sukruth Shashikumar
- Department of Anesthesiology, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
| | - Robert A Knight
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA ; Department of Physics, Oakland University, Rochester, MI, USA
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Urra X, Miró F, Chamorro A, Planas AM. Antigen-specific immune reactions to ischemic stroke. Front Cell Neurosci 2014; 8:278. [PMID: 25309322 PMCID: PMC4162361 DOI: 10.3389/fncel.2014.00278] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/22/2014] [Indexed: 12/24/2022] Open
Abstract
Brain proteins are detected in the cerebrospinal fluid (CSF) and blood of stroke patients and their concentration is related to the extent of brain damage. Antibodies against brain antigens develop after stroke, suggesting a humoral immune response to the brain injury. Furthermore, induced immune tolerance is beneficial in animal models of cerebral ischemia. The presence of circulating T cells sensitized against brain antigens, and antigen presenting cells (APCs) carrying brain antigens in draining lymphoid tissue of stroke patients support the notion that stroke might induce antigen-specific immune responses. After stroke, brain proteins that are normally hidden from the periphery, inflammatory mediators, and danger signals can exit the brain through several efflux routes. They can reach the blood after leaking out of the damaged blood-brain barrier (BBB) or following the drainage of interstitial fluid to the dural venous sinus, or reach the cervical lymph nodes through the nasal lymphatics following CSF drainage along the arachnoid sheaths of nerves across the nasal submucosa. The route and mode of access of brain antigens to lymphoid tissue could influence the type of response. Central and peripheral tolerance prevents autoimmunity, but the actual mechanisms of tolerance to brain antigens released into the periphery in the presence of inflammation, danger signals, and APCs, are not fully characterized. Stroke does not systematically trigger autoimmunity, but under certain circumstances, such as pronounced systemic inflammation or infection, autoreactive T cells could escape the tolerance controls. Further investigation is needed to elucidate whether antigen-specific immune events could underlie neurological complications impairing recovery from stroke.
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Affiliation(s)
- Xabier Urra
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic Barcelona, Spain ; August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Francesc Miró
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Angel Chamorro
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic Barcelona, Spain ; August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Anna M Planas
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain ; Department of Brain Ischemia and Neurodegeneration, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC) Barcelona, Spain
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Regenhardt RW, Bennion DM, Sumners C. Cerebroprotective action of angiotensin peptides in stroke. Clin Sci (Lond) 2014; 126:195-205. [PMID: 24102099 PMCID: PMC7453725 DOI: 10.1042/cs20130324] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The goal of the present review is to examine the evidence for beneficial actions of manipulation of the RAS (renin-angiotensin system) in stroke, with particular focus on Ang-(1-7) [angiotensin-(1-7)] and its receptor Mas. The RAS appears to be highly involved in the multifactorial pathophysiology of stroke. Blocking the effects of AngII (angiotensin II) at AT1R (AngII type 1 receptor), through the use of commonly prescribed ACE (angiotensin-converting enzyme) inhibitors or AT1R blockers, has been shown to have therapeutic effects in both ischaemic and haemorrhagic stroke. In contrast with the deleterious actions of over activation of AT1R by AngII, stimulation of AT2Rs (AngII type 2 receptors) in the brain has been demonstrated to elicit beneficial effects in stroke. Likewise, the ACE2/Ang-(1-7)/Mas axis of the RAS has been shown to have therapeutic effects in stroke when activated, countering the effects of the ACE/AngII/AT1R axis. Studies have demonstrated that activating this axis in the brain elicits beneficial cerebral effects in rat models of ischaemic stroke, and we have also demonstrated the cerebroprotective potential of this axis in haemorrhagic stroke using stroke-prone spontaneously hypertensive rats and collagenase-induced striatal haemorrhage. The mechanism of cerebroprotection elicited by ACE2/Ang-(1-7)/Mas activation includes anti-inflammatory effects within the brain parenchyma. The major hurdle to overcome in translating these results to humans is devising strategies to activate the ACE2/Ang-(1-7)/Mas cerebroprotective axis using post-stroke treatments that can be administered non-invasively.
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Affiliation(s)
- Robert W. Regenhardt
- Department of Physiology and Functional Genomics & McKnight Brain Institute, University of Florida, 1600 SW Archer Road, PO Box 100274, Gainesville, FL 32610-0274, USA
| | - Douglas M. Bennion
- Department of Physiology and Functional Genomics & McKnight Brain Institute, University of Florida, 1600 SW Archer Road, PO Box 100274, Gainesville, FL 32610-0274, USA
| | - Colin Sumners
- Department of Physiology and Functional Genomics & McKnight Brain Institute, University of Florida, 1600 SW Archer Road, PO Box 100274, Gainesville, FL 32610-0274, USA
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Barber PA. Magnetic resonance imaging of ischemia viability thresholds and the neurovascular unit. SENSORS 2013; 13:6981-7003. [PMID: 23711462 PMCID: PMC3715273 DOI: 10.3390/s130606981] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 01/24/2023]
Abstract
Neuroimaging has improved our understanding of the evolution of stroke at discreet time points helping to identify irreversibly damaged and potentially reversible ischemic brain. Neuroimaging has also contributed considerably to the basic premise of acute stroke therapy which is to salvage some portion of the ischemic region from evolving into infarction, and by doing so, maintaining brain function and improving outcome. The term neurovascular unit (NVU) broadens the concept of the ischemic penumbra by linking the microcirculation with neuronal-glial interactions during ischemia reperfusion. Strategies that attempt to preserve the individual components (endothelium, glia and neurons) of the NVU are unlikely to be helpful if blood flow is not fully restored to the microcirculation. Magnetic resonance imaging (MRI) is the foremost imaging technology able to bridge both basic science and the clinic via non-invasive real time high-resolution anatomical delineation of disease manifestations at the molecular and ionic level. Current MRI based technologies have focused on the mismatch between perfusion-weighted imaging (PWI) and diffusion weighted imaging (DWI) signals to estimate the tissue that could be saved if reperfusion was achieved. Future directions of MRI may focus on the discordance of recanalization and reperfusion, providing complimentary pathophysiological information to current compartmental paradigms of infarct core (DWI) and penumbra (PWI) with imaging information related to cerebral blood flow, BBB permeability, inflammation, and oedema formation in the early acute phase. In this review we outline advances in our understanding of stroke pathophysiology with imaging, transcending animal stroke models to human stroke, and describing the potential translation of MRI to image important interactions relevant to acute stroke at the interface of the neurovascular unit.
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Affiliation(s)
- Philip A Barber
- Department of Clinical Neurosciences, University of Calgary, Calgary, Canada.
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Sumbria RK, Boado RJ, Pardridge WM. Combination stroke therapy in the mouse with blood-brain barrier penetrating IgG-GDNF and IgG-TNF decoy receptor fusion proteins. Brain Res 2013; 1507:91-6. [PMID: 23428543 DOI: 10.1016/j.brainres.2013.02.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/07/2013] [Accepted: 02/14/2013] [Indexed: 01/09/2023]
Abstract
Stroke therapy may be optimized by combination therapy with both a neuroprotective neurotrophin and an anti-inflammatory agent. In the present work, the model neurotrophin is glial cell line-derived neurotrophic factor (GDNF), and the model anti-inflammatory agent is the type II tumor necrosis factor receptor (TNFR) decoy receptor. Both the GDNF and the TNFR are large molecules that do not cross the blood-brain barrier (BBB), which is intact in the early hours after stroke when neural rescue is still possible. The GDNF and the TNFR decoy receptor were re-engineered for BBB transport as IgG fusion proteins, wherein the GDNF or the TNFR are fused to the heavy chain of a chimeric monoclonal antibody (MAb) against the mouse transferrin receptor (TfR), and these fusion proteins are designated cTfRMAb-GDNF and cTfRMAb-TNFR, respectively. Mice were treated intravenously with (a) saline, (b) GDNF alone, (c) the cTfRMAb-GDNF fusion protein alone, or (d) the combined cTfRMAb-GDNF and cTfRMAb-TNFR fusion proteins, following a 1-h reversible middle cerebral artery occlusion (MCAO). The cTfRMAb-GDNF fusion protein alone caused a significant 25% and 30% reduction in hemispheric and cortical stroke volumes. Combined treatment with the cTfRMAb-GDNF and cTfRMAb-TNFR fusion proteins caused a significant 54%, 69% and 30% reduction in hemispheric, cortical and subcortical stroke volumes. Conversely, intravenous GDNF had no therapeutic effect. In conclusion, combination treatment with BBB penetrating IgG-GDNF and IgG-TNFR fusion proteins enhances the therapeutic effect of single treatment with the IgG-GDNF fusion protein following delayed intravenous administration in acute stroke.
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Wunder A, Schoknecht K, Stanimirovic DB, Prager O, Chassidim Y. Imaging blood-brain barrier dysfunction in animal disease models. Epilepsia 2013; 53 Suppl 6:14-21. [PMID: 23134491 DOI: 10.1111/j.1528-1167.2012.03698.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The blood-brain barrier (BBB) is a highly complex structure, which separates the extracellular fluid of the central nervous system (CNS) from the blood of CNS vessels. A wide range of neurologic conditions, including stroke, epilepsy, Alzheimer's disease, and brain tumors, are associated with perturbations of the BBB that contribute to their pathology. The common consequence of a BBB dysfunction is increased permeability, leading to extravasation of plasma constituents and vasogenic brain edema. The BBB impairment can persist for long periods, being involved in secondary inflammation and neuronal dysfunction, thus contributing to disease pathogenesis. Therefore, reliable imaging of the BBB impairment is of major importance in both clinical management of brain diseases and in experimental research. From landmark studies by Ehrlich and Goldman, the use of dyes (probes) has played a critical role in understanding BBB functions. In recent years methodologic advances in morphologic and functional brain imaging have provided insight into cellular and molecular interactions underlying BBB dysfunction in animal disease models. These imaging techniques, which range from in situ staining to noninvasive in vivo imaging, have different spatial resolution, sensitivity, and capacity for quantitative and kinetic measures of the BBB impairment. Despite significant advances, the translation of these techniques into clinical applications remains slow. This review outlines key recent advances in imaging techniques that have contributed to the understanding of BBB dysfunction in disease and discusses major obstacles and opportunities to advance these techniques into the clinical realm.
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Affiliation(s)
- Andreas Wunder
- Department of Experimental Neurology, Center for Stroke Research Berlin, Charité-University Medicine Berlin, Berlin, Germany.
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Affiliation(s)
- Pavel Yanev
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
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Quantitative MRI reveals the elderly ischemic brain is susceptible to increased early blood-brain barrier permeability following tissue plasminogen activator related to claudin 5 and occludin disassembly. J Cereb Blood Flow Metab 2011; 31:1874-85. [PMID: 21610723 PMCID: PMC3185885 DOI: 10.1038/jcbfm.2011.79] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Great uncertainty exists as to whether aging enhances the detrimental effects of tissue plasminogen activator (tPA) on vascular integrity of the ischemic brain. We hypothesized that tPA treatment would augment ischemic injury by causing increased blood-brain barrier (BBB) breakdown as determined by quantitative serial T(1) and T(2) magnetic resonance imaging (MRI), and the transfer constant for gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) from blood to brain in aged (18 to 20 months) compared with young (3 to 4 months) Wistar rats after middle cerebral artery occlusion, mediated through the acute disassembly of claudin 5 and occludin. Increased T(2) values over the first hour of postreperfusion were independently augmented following treatment with tPA (P<0.001) and aging (P<0.01), supporting a synergistic effect of tPA on the aged ischemic brain. Blood-brain barrier permeability for Gd-DTPA (K(Gd)) was substantial following reperfusion in all animal groups and was exacerbated by tPA treatment in the elderly rat (P<0.001). The frequency of hematoma formation was proportionately increased in the elderly ischemic brain (P<0.05). Both tPA and age independently increased claudin 5 and occludin phosphorylation during ischemia. Early BBB permeability detected by quantitative MRI following ischemic stroke is enhanced by increased age and tPA and is related to claudin 5 and occludin phosphorylation.
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Hoffmann A, Bredno J, Wendland MF, Derugin N, Hom J, Schuster T, Su H, Ohara PT, Young WL, Wintermark M. Validation of in vivo magnetic resonance imaging blood-brain barrier permeability measurements by comparison with gold standard histology. Stroke 2011; 42:2054-60. [PMID: 21636816 DOI: 10.1161/strokeaha.110.597997] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE We sought to validate the blood-brain barrier permeability measurements extracted from perfusion-weighted MRI through a relatively simple and frequently applied model, the Patlak model, by comparison with gold standard histology in a rat model of ischemic stroke. METHODS Eleven spontaneously hypertensive rats and 11 Wistar rats with unilateral 2-hour filament occlusion of the right middle cerebral artery underwent imaging during occlusion at 4 hours and 24 hours after reperfusion. Blood-brain barrier permeability was imaged by gradient echo imaging after the first pass of the contrast agent bolus and quantified by a Patlak analysis. Blood-brain barrier permeability was shown on histology by the extravasation of Evans blue on fluorescence microscopy sections matching location and orientation of MR images. Cresyl-violet staining was used to detect and characterize hemorrhage. Landmark-based elastic image registration allowed a region-by-region comparison of permeability imaging at 24 hours with Evans blue extravasation and hemorrhage as detected on histological slides obtained immediately after the 24-hour image set. RESULTS Permeability values in the nonischemic tissue (marginal mean ± SE: 0.15 ± 0.019 mL/min 100 g) were significantly lower compared to all permeability values in regions of Evans blue extravasation or hemorrhage. Permeability values in regions of weak Evans blue extravasation (0.23 ± 0.016 mL/min 100 g) were significantly lower compared to permeability values of in regions of strong Evans blue extravasation (0.29 ± 0.020 mL/min 100 g) and macroscopic hemorrhage (0.35 ± 0.049 mL/min 100 g). Permeability values in regions of microscopic hemorrhage (0.26 ± 0.024 mL/min 100 g) only differed significantly from values in regions of nonischemic tissue (0.15 ± 0.019 mL/min 100 g). CONCLUSIONS Areas of increased permeability measured in vivo by imaging coincide with blood-brain barrier disruption and hemorrhage observed on gold standard histology.
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Affiliation(s)
- Angelika Hoffmann
- University of Virginia, Department of Radiology, Neuroradiology Division, Charlottesville, VA 22908, USA
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Nagaraja TN, Ewing JR, Karki K, Jacobs PE, Divine GW, Fenstermacher JD, Patlak CS, Knight RA. MRI and quantitative autoradiographic studies following bolus injections of unlabeled and (14)C-labeled gadolinium-diethylenetriaminepentaacetic acid in a rat model of stroke yield similar distribution volumes and blood-to-brain influx rate constants. NMR IN BIOMEDICINE 2011; 24:547-558. [PMID: 21674656 PMCID: PMC3543112 DOI: 10.1002/nbm.1625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 09/09/2010] [Accepted: 09/14/2010] [Indexed: 05/30/2023]
Abstract
In previous studies on a rat model of transient cerebral ischemia, the blood and brain concentrations of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) following intravenous bolus injection were repeatedly assessed by dynamic contrast-enhanced (DCE)-MRI, and blood-to-brain influx rate constants (K(i)) were calculated from Patlak plots of the data in areas with blood-brain barrier (BBB) opening. For concurrent validation of these findings, after completing the DCE-MRI study, radiolabeled sucrose or α-aminoisobutyric acid was injected intravenously, and the brain disposition and K(i) values were calculated by quantitative autoradiography (QAR) assay employing the single-time equation. To overcome two of the shortcomings of this comparison, the present experiments were carried out with a radiotracer virtually identical to Gd-DTPA, Gd-[(14)C]DTPA, and K(i) was calculated from both sets of data by the single-time equation. The protocol included 3 h of middle cerebral artery occlusion and 2.5 h of reperfusion in male Wistar rats (n = 15) preceding the DCE-MRI Gd-DTPA and QAR Gd-[(14)C]DTPA measurements. In addition to K(i) , the tissue-to-blood concentration ratios, or volumes of distribution (V(R) ), were calculated. The regions of BBB opening were similar on the MRI maps and autoradiograms. Within them, V(R) was nearly identical for Gd-DTPA and Gd-[(14)C]DTPA, and K(i) was slightly, but not significantly, higher for Gd-DTPA than for Gd-[(14)C]DTPA. The K(i) values were well correlated (r = 0.67; p = 0.001). When the arterial concentration-time curve of Gd-DTPA was adjusted to match that of Gd-[(14)C]DTPA, the two sets of K(i) values were equal and statistically comparable with those obtained previously by Patlak plots (the preferred, less model-dependent, approach) of the same data (p = 0.2-0.5). These findings demonstrate that this DCE-MRI technique accurately measures the Gd-DTPA concentration in blood and brain, and that K(i) estimates based on such data are good quantitative indicators of BBB injury.
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Choe CU, Lewerenz J, Gerloff C, Magnus T, Donzelli S. Nitroxyl in the central nervous system. Antioxid Redox Signal 2011; 14:1699-711. [PMID: 21235347 DOI: 10.1089/ars.2010.3852] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Nitroxyl (HNO) is the one-electron-reduced and protonated congener of nitric oxide (NO). Compared to NO, it is far more reactive with thiol groups either in proteins or in small antioxidant molecules either converting those into sulfinamides or inducing disulfide bond formation. HNO might mediate cytoprotective changes of protein function through thiol modifications. However, HNO is a strong oxidant that in vitro reacts with glutathione to form glutathione disulfide and glutathione sulfinamide. The resulting oxidative stress might aggravate tissue damage in inflammatory diseases. In this review, we will summarize the current knowledge of how exogenous HNO affects the central nervous system, especially nerve cells and glia in health and disease. Unlike most other organs, the brain is separated from the circulation by the blood-brain barrier, which limits access of many pharmacological compounds. Given that, we will review what is known about the ability of currently used HNO donors to cross the blood-brain barrier. Moreover, considering that the physiology and composition of the brain has unique properties, for example, expression of brain-specific enzymes like neuronal NO synthase, its high iron content, and increased energy metabolism, we will discuss possible sources of endogenous HNO in the brain.
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Affiliation(s)
- Chi-Un Choe
- Department of Neurology, University Hospital Hamburg-Eppendorf, Germany
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Kenne E, Lindbom L. Imaging inflammatory plasma leakage in vivo. Thromb Haemost 2011; 105:783-9. [PMID: 21437352 DOI: 10.1160/th10-10-0635] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 02/10/2011] [Indexed: 12/15/2022]
Abstract
Increased vascular permeability and consequent plasma leakage from postcapillary venules is a cardinal sign of inflammation. Although the movement of plasma constituents from the vasculature to the affected tissue aids in clearing the inflammatory stimulus, excessive plasma extravasation can lead to hospitalisation or death in cases such as influenza-induced pneumonia, burns or brain injury. The use of intravital imaging has significantly contributed to the understanding of the mechanisms controlling the vascular permeability alterations that occur during inflammation. Today, intravital imaging can be performed using optical and non-optical techniques. Optical techniques, which are generally used in experimental settings, include traditional intravital fluorescence microscopy and near-infrared fluorescence imaging. Magnetic resonance (MRI) and radioisotopic imaging are used mainly in the clinical setting, but are increasingly used in experimental work, and can detect plasma leakage without optics. Although these methods are all able to visualise inflammatory plasma leakage in vivo, the spatial and temporal resolution differs between the techniques. In addition, they vary with regards to invasiveness and availability. This overview discusses the use of imaging techniques in the visualisation of inflammatory plasma leakage.
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Affiliation(s)
- E Kenne
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Abulrob A, Brunette E, Slinn J, Baumann E, Stanimirovic D. In vivo optical imaging of ischemic blood-brain barrier disruption. Methods Mol Biol 2011; 763:423-439. [PMID: 21874469 DOI: 10.1007/978-1-61779-191-8_29] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The blood-brain barrier (BBB) disruption following cerebral ischemia (stroke) contributes to the development of life-threatening brain edema. Recent studies suggested that the ischemic BBB disruption is not uniform throughout the affected brain region. The aim of this study was to establish in vivo optical imaging methods to assess the size selectivity and spatial distribution of the BBB disruption after a focal cerebral ischemia. The BBB permeability was assessed in mice subjected to a 60-min middle cerebral artery occlusion and 24 h of reperfusion using in vivo time domain near-infrared optical imaging after contrast enhancement with two tracers of different molecular size, Cy5.5 (1 kDa) and Cy5.5 conjugated with bovine serum albumin (BSA) (67 kDa). Volumetric reconstruction of contrast-enhanced brain areas in vivo and ex vivo indicated that the BSA-Cy5.5-enhancement is identical to the volume of infarct determined by TTC staining, whereas the volume of enhancement with Cy5.5 was 40% greater. The volume differential between areas of BBB disruption for small and large-size molecules could be useful for determining the size of peri-infarct tissues (penumbra) that can respond to neuroprotective therapies.
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Affiliation(s)
- Abedelnasser Abulrob
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON, Canada.
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Nagaraja TN, Knight RA, Ewing JR, Karki K, Nagesh V, Fenstermacher JD. Multiparametric magnetic resonance imaging and repeated measurements of blood-brain barrier permeability to contrast agents. Methods Mol Biol 2011; 686:193-212. [PMID: 21082372 DOI: 10.1007/978-1-60761-938-3_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Breakdown of the blood-brain barrier (BBB) is present in several neurological disorders such as stroke, brain tumors, and multiple sclerosis. Noninvasive evaluation of BBB breakdown is important for monitoring disease progression and evaluating therapeutic efficacy in such disorders. One of the few techniques available for noninvasively and repeatedly localizing and quantifying BBB damage is magnetic resonance imaging (MRI). This usually involves the intravenous administration of a gadolinium-containing MR contrast agent (MRCA) such as Gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), followed by dynamic contrast-enhanced MR imaging (DCE-MRI) of brain and blood, and analysis of the resultant data to derive indices of blood-to-brain transfer. There are two advantages to this approach. First, measurements can be made repeatedly in the same animal; for instance, they can be made before drug treatment and then again after treatment to assess efficacy. Secondly, MRI studies can be multiparametric. That is, MRI can be used to assess not only a blood-to-brain transfer or influx rate constant (Ki or K1) by DCE-MRI but also complementary parameters such as: (1) cerebral blood flow (CBF), done in our hands by arterial spin-tagging (AST) methods; (2) magnetization transfer (MT) parameters, most notably T1sat, which appear to reflect brain water-protein interactions plus BBB and tissue dysfunction; (3) the apparent diffusion coefficient of water (ADCw) and/or diffusion tensor, which is a function of the size and tortuosity of the extracellular space; and (4) the transverse relaxation time by T2-weighted imaging, which demarcates areas of tissue abnormality in many cases. The accuracy and reliability of two of these multiparametric MRI measures, CBF by AST and DCE-MRI determined influx of Gd-DTPA, have been established by nearly congruent quantitative autoradiographic (QAR) studies with appropriate radiotracers. In addition, some of their linkages to local pathology have been shown via corresponding light microscopy and fluorescence imaging. This chapter describes: (1) multiparametric MRI techniques with emphasis on DCE-MRI and AST-MRI; (2) the measurement of the blood-to-brain influx rate constant and CBF; and (3) the role of each in determining BBB permeability.
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Israeli D, Tanne D, Daniels D, Last D, Shneor R, Guez D, Landau E, Roth Y, Ocherashvilli A, Bakon M, Hoffman C, Weinberg A, Volk T, Mardor Y. The application of MRI for depiction of subtle blood brain barrier disruption in stroke. Int J Biol Sci 2010; 7:1-8. [PMID: 21209786 PMCID: PMC3014550 DOI: 10.7150/ijbs.7.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/13/2010] [Indexed: 12/05/2022] Open
Abstract
The development of imaging methodologies for detecting blood-brain-barrier (BBB) disruption may help predict stroke patient's propensity to develop hemorrhagic complications following reperfusion. We have developed a delayed contrast extravasation MRI-based methodology enabling real-time depiction of subtle BBB abnormalities in humans with high sensitivity to BBB disruption and high spatial resolution. The increased sensitivity to subtle BBB disruption is obtained by acquiring T1-weighted MRI at relatively long delays (~15 minutes) after contrast injection and subtracting from them images acquired immediately after contrast administration. In addition, the relatively long delays allow for acquisition of high resolution images resulting in high resolution BBB disruption maps. The sensitivity is further increased by image preprocessing with corrections for intensity variations and with whole body (rigid+elastic) registration. Since only two separate time points are required, the time between the two acquisitions can be used for acquiring routine clinical data, keeping the total imaging time to a minimum. A proof of concept study was performed in 34 patients with ischemic stroke and 2 patients with brain metastases undergoing high resolution T1-weighted MRI acquired at 3 time points after contrast injection. The MR images were pre-processed and subtracted to produce BBB disruption maps. BBB maps of patients with brain metastases and ischemic stroke presented different patterns of BBB opening. The significant advantage of the long extravasation time was demonstrated by a dynamic-contrast-enhancement study performed continuously for 18 min. The high sensitivity of our methodology enabled depiction of clear BBB disruption in 27% of the stroke patients who did not have abnormalities on conventional contrast-enhanced MRI. In 36% of the patients, who had abnormalities detectable by conventional MRI, the BBB disruption volumes were significantly larger in the maps than in conventional MRI. These results demonstrate the advantages of delayed contrast extravasation in increasing the sensitivity to subtle BBB disruption in ischemic stroke patients. The calculated disruption maps provide clear depiction of significant volumes of BBB disruption unattainable by conventional contrast-enhanced MRI.
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Dankbaar JW, Hom J, Schneider T, Cheng SC, Bredno J, Lau BC, van der Schaaf IC, Wintermark M. Dynamic perfusion-CT assessment of early changes in blood brain barrier permeability of acute ischaemic stroke patients. J Neuroradiol 2010; 38:161-6. [PMID: 20950860 DOI: 10.1016/j.neurad.2010.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 08/11/2010] [Accepted: 08/12/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND PURPOSE Damage to the blood brain barrier (BBB) may lead to haemorrhagic transformation after ischaemic stroke. The purpose of this study was to evaluate the effect of patient characteristics and stroke severity on admission BBB permeability (BBBP) values measured with perfusion-CT (PCT) in acute ischaemic stroke patients. METHODS We retrospectively identified 65 patients with proven ischaemic stroke admitted within 12 hours after symptom onset. Patients' charts were reviewed for demographic variables and vascular risk factors. The Patlak's model was applied to calculate BBBP values from the PCT data in the infarct core, penumbra and non-ischaemic tissue in the contralateral hemisphere. Mean BBBP values and their 95% confidence intervals (CI) were calculated in the different tissue types. Effects of demographic variables and risk factors on BBBP were analyzed using a multivariate, generalized estimating equations (GEE) model. RESULTS BBBP values in the infarct core (mean [95%CI]: 2.48 [2.16-2.85]) and penumbra (2.48 [2.21-2.79]) were significantly higher than in non-ischaemic tissue (2.12 [1.88-2.39]). Multivariate analysis demonstrated that collateral filling has effect on BBBP. Less elevated BBBP values were associated with more than 50% collateral filling. CONCLUSIONS BBBP values are increased in ischaemic brain tissue on the admission PCT scan of acute ischaemic stroke patients. Less abnormally elevated BBBP values were observed in patients with more than 50% collateral filling, possibly explaining why there is a relationship between more collateral filling and a lower incidence of haemorrhagic transformation.
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Affiliation(s)
- J W Dankbaar
- University of California, Department of Radiology and Biomedical Imaging, Neuroradiology Section, San Francisco, USA
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Karki K, Knight RA, Shen LH, Kapke A, Lu M, Li Y, Chopp M. Chronic brain tissue remodeling after stroke in rat: a 1-year multiparametric magnetic resonance imaging study. Brain Res 2010; 1360:168-76. [PMID: 20828544 DOI: 10.1016/j.brainres.2010.08.098] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 08/27/2010] [Accepted: 08/30/2010] [Indexed: 11/17/2022]
Abstract
Rats subjected to 2h of transient middle cerebral artery occlusion were studied temporally over 1 year by magnetic resonance imaging (MRI) and behavioral testing. Multiparameter MRI measures of T(2), T(1), T(1) in the presence of off-resonance saturation of the bound proton signal (T(1sat)), apparent diffusion coefficient (ADC) and susceptibility-weighted imaging (SWI) were obtained at 1 day, 1, 2, 3 and 4 weeks, and 3, 6, 9 and 12 months post-ischemia. Regions of interest included: ischemic core (damaged both at 1 day and later); new lesion (normal at 1 day, but damaged later); and recovery (damaged at 1 day, but normal later) areas. Hematoxylin and eosin, Prussian blue and ED-1, a monoclonal antibody murine macrophage marker, stainings were performed for histological assessment. Core area T(2) and ADC values increased until ~6 months, and T(1) and T(1sat) until ~12 months. New lesion area MRI parameter values increased until ~6 months (T(2), T(1) and ADC), or ~1 year (T(1sat)). Lesion area was largest at 1day (mean±SD: 37.0±13.7mm(2)) and smallest at 1 year (18.1±10.5mm(2)). Recovery area was largest at 3 weeks (8.9±3.8mm(2)) and smallest at 1year (6.4±3.3mm(2)). The ipsilateral/contralateral ventricle area ratio was 0.7±0.2 at 1 day and increased significantly at 1 year (2.4±0.7). Iron-laden macrophages, histologically confirmed at 1 year, were detected in the lesion borders by SWI at 3, 6, 9 and 12 months. Our data indicate that MRI detectable changes of ischemia-damaged brain tissue continue for at least 1 year post-ischemia.
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Affiliation(s)
- Kishor Karki
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
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Lu H, Zhao J, Li M, Cheng Y, Li Y, You X, Zhao Y. Microvessel changes after post-ischemic benign and malignant hyperemia: experimental study in rats. BMC Neurol 2010; 10:24. [PMID: 20398382 PMCID: PMC2868835 DOI: 10.1186/1471-2377-10-24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 04/16/2010] [Indexed: 02/07/2023] Open
Abstract
Background The present investigation was designed to elucidate the use of dynamic contrast enhanced perfusion MR imaging (DCE pMRI) in characterizing hyperemia, including microvessel changes, and to examine whether DCE pMRI can predict benign or malignant hyperemia. Methods Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) by intraluminal suture placement. All rats were randomized to 4 groups: MCAO for 0.5 hours followed by saline treatment (10 ml/kg; group 1); MCAO for 3 hours followed by treatment with saline (group 2) or urokinase (25000 IU/kg; group 3); and MCAO for 6 hours followed by urokinase treatment (group 4). Relative cerebral blood volume (rCBV) and relative maximum slope of increase of the signal intensity time curve (rMSI) were quantitatively analyzed from MRI. Microvessel diameter and blood-brain barrier disruption obtained by laser scanning confocal microscopy (LSCM) as well as transmission electron microscopy (TEM) were obtained for correlative study. Results Benign hyperemia was noticed only in group 1; malignant hyperemia was seen in group 3. Although the rCBV of malignant hyperemia was slightly higher than in benign hyperemia (P > 0.05), the rMSI, on the other hand, was significantly lower (P < 0.05). Fluoro-isothiocyanate dextran (FITC-dextran) extravasations, marked glial end-foot process swelling, and significant vasodilatation were seen in malignant hyperemia, while no or mild leakage of FITC-dextran and slight glial end-foot process swelling occurred in benign hyperemia. Conclusion Our findings indicate that DCE pMRI can characterize post-ischemic hyperemia and correlates well with microvascular damage.
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Affiliation(s)
- Haitao Lu
- Department of Diagnostic and Interventinal Radiololgy, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, PR China
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Taheri S, Candelario-Jalil E, Estrada EY, Rosenberg GA. Spatiotemporal correlations between blood-brain barrier permeability and apparent diffusion coefficient in a rat model of ischemic stroke. PLoS One 2009; 4:e6597. [PMID: 19668371 PMCID: PMC2719093 DOI: 10.1371/journal.pone.0006597] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 07/16/2009] [Indexed: 12/03/2022] Open
Abstract
Variations in apparent diffusion coefficient of water (ADC) and blood-brain barrier (BBB) permeability after ischemia have been suggested, though the correlation between ADC alterations and BBB opening remains to be studied. We hypothesized that there are correlations between the alteration of ADC and BBB permeability. Rats were subjected to 2 h of transient middle cerebral artery occlusion and studied at 3 and 48 h of reperfusion, which are crucial times of BBB opening. BBB permeability and ADC values were measured by dynamic contrast-enhanced MRI and diffusion-weighted imaging, respectively. Temporal and spatial analyses of the evolution of BBB permeability and ADC alteration in cortical and subcortical regions were conducted along with the correlation between ADC and BBB permeability data. We found significant increases in BBB leakage and reduction in ADC values between 3 and 48 h of reperfusion. We identified three MR tissue signature models: high Ki and low ADC, high Ki and normal ADC, and normal Ki and low ADC. Over time, areas with normal Ki and low ADC transformed into areas with high Ki. We observed a pattern of lesion evolution where the extent of initial ischemic injury reflected by ADC abnormalities determines vascular integrity. Our results suggest that regions with vasogenic edema alone are not likely to develop low ADC by 48 h and may undergo recovery.
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Affiliation(s)
- Saeid Taheri
- Department of Neurology, University of New Mexico, Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Eduardo Candelario-Jalil
- Department of Neurology, University of New Mexico, Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Eduardo Y. Estrada
- Department of Neurology, University of New Mexico, Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Gary A. Rosenberg
- Department of Neurology, University of New Mexico, Health Sciences Center, Albuquerque, New Mexico, United States of America
- * E-mail:
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Choe CU, Lewerenz J, Fischer G, Uliasz TF, Espey MG, Hummel FC, King SB, Schwedhelm E, Böger RH, Gerloff C, Hewett SJ, Magnus T, Donzelli S. Nitroxyl exacerbates ischemic cerebral injury and oxidative neurotoxicity. J Neurochem 2009; 110:1766-73. [PMID: 19619135 DOI: 10.1111/j.1471-4159.2009.06266.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitroxyl (HNO) donor compounds function as potent vasorelaxants, improve myocardial contractility and reduce ischemia-reperfusion injury in the cardiovascular system. With respect to the nervous system, HNO donors have been shown to attenuate NMDA receptor activity and neuronal injury, suggesting that its production may be protective against cerebral ischemic damage. Hence, we studied the effect of the classical HNO-donor, Angeli's salt (AS), on a cerebral ischemia/reperfusion injury in a mouse model of experimental stroke and on related in vitro paradigms of neurotoxicity. I.p. injection of AS (40 mumol/kg) in mice prior to middle cerebral artery occlusion exacerbated cortical infarct size and worsened the persistent neurological deficit. AS not only decreased systolic blood pressure, but also induced systemic oxidative stress in vivo indicated by increased isoprostane levels in urine and serum. In vitro, neuronal damage induced by oxygen-glucose-deprivation of mature neuronal cultures was exacerbated by AS, although there was no direct effect on glutamate excitotoxicity. Finally, AS exacerbated oxidative glutamate toxicity - that is, cell death propagated via oxidative stress in immature neurons devoid of ionotropic glutamate receptors. Taken together, our data indicate that HNO might worsen cerebral ischemia-reperfusion injury by increasing oxidative stress and decreasing brain perfusion at concentrations shown to be cardioprotective in vivo.
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Affiliation(s)
- Chi-un Choe
- Department of Neurology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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Near-infrared fluorescence imaging with fluorescently labeled albumin: A novel method for non-invasive optical imaging of blood–brain barrier impairment after focal cerebral ischemia in mice. J Neurosci Methods 2009; 180:126-32. [DOI: 10.1016/j.jneumeth.2009.03.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 03/03/2009] [Accepted: 03/05/2009] [Indexed: 11/22/2022]
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40
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Knight RA, Karki K, Ewing JR, Divine GW, Fenstermacher JD, Patlak CS, Nagaraja TN. Estimating blood and brain concentrations and blood-to-brain influx by magnetic resonance imaging with step-down infusion of Gd-DTPA in focal transient cerebral ischemia and confirmation by quantitative autoradiography with Gd-[(14)C]DTPA. J Cereb Blood Flow Metab 2009; 29:1048-58. [PMID: 19319145 PMCID: PMC4205544 DOI: 10.1038/jcbfm.2009.20] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An intravenous step-down infusion procedure that maintained a constant gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) blood concentration and magnetic resonance imaging (MRI) were used to localize and quantify the blood-brain barrier (BBB) opening in a rat model of transient cerebral ischemia (n=7). Blood-to-brain influx rate constant (K(i)) values of Gd-DTPA from such regions were estimated using MRI-Patlak plots and compared with the K(i) values of Gd-[(14)C]DTPA, determined minutes later in the same rats with an identical step-down infusion, quantitative autoradiography (QAR), and single-time equation. The normalized plasma concentration-time integrals were identical for Gd-DTPA and Gd-[(14)C]DTPA, indicating that the MRI protocol yielded reliable estimates of plasma Gd-DTPA levels. In six rats with a BBB opening, 14 spatially similar regions of extravascular Gd-DTPA enhancement and Gd-[(14)C]DTPA leakage, including one very small area, were observed. The terminal tissue-plasma ratios of Gd-[(14)C]DTPA tended to be slightly higher than those of Gd-DTPA in these regions, but the differences were not significant. The MRI-derived K(i) values for Gd-DTPA closely agreed and correlated well with those obtained for Gd-[(14)C]DTPA. In summary, MRI estimates of Gd-DTPA concentration in the plasma and brain and the influx rate are quantitatively and spatially accurate with step-down infusions.
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Affiliation(s)
- Robert A Knight
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan 48202, USA.
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41
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Chen Z, Yu D, Wang S, Zhang N, Ma C, Lu Z. Biocompatible Nanocomplexes for Molecular Targeted MRI Contrast Agent. NANOSCALE RESEARCH LETTERS 2009; 4:618-626. [PMID: 20596430 PMCID: PMC2894099 DOI: 10.1007/s11671-009-9286-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 03/05/2009] [Indexed: 05/29/2023]
Abstract
Accurate diagnosis in early stage is vital for the treatment of Hepatocellular carcinoma. The aim of this study was to investigate the potential of poly lactic acid-polyethylene glycol/gadolinium-diethylenetriamine-pentaacetic acid (PLA-PEG/Gd-DTPA) nanocomplexes using as biocompatible molecular magnetic resonance imaging (MRI) contrast agent. The PLA-PEG/Gd-DTPA nanocomplexes were obtained using self-assembly nanotechnology by incubation of PLA-PEG nanoparticles and the commercial contrast agent, Gd-DTPA. The physicochemical properties of nanocomplexes were measured by atomic force microscopy and photon correlation spectroscopy. The T(1)-weighted MR images of the nanocomplexes were obtained in a 3.0 T clinical MR imager. The stability study was carried out in human plasma and the distribution in vivo was investigated in rats. The mean size of the PLA-PEG/Gd-DTPA nanocomplexes was 187.9 +/- 2.30 nm, and the polydispersity index was 0.108, and the zeta potential was -12.36 +/- 3.58 mV. The results of MRI test confirmed that the PLA-PEG/Gd-DTPA nanocomplexes possessed the ability of MRI, and the direct correlation between the MRI imaging intensities and the nano-complex concentrations was observed (r = 0.987). The signal intensity was still stable within 2 h after incubation of the nanocomplexes in human plasma. The nanocomplexes gave much better image contrast effects and longer stagnation time than that of commercial contrast agent in rat liver. A dose of 0.04 mmol of gadolinium per kilogram of body weight was sufficient to increase the MRI imaging intensities in rat livers by five-fold compared with the commercial Gd-DTPA. PLA-PEG/Gd-DTPA nanocomplexes could be prepared easily with small particle sizes. The nanocomplexes had high plasma stability, better image contrast effect, and liver targeting property. These results indicated that the PLA-PEG/Gd-DTPA nanocomplexes might be potential as molecular targeted imaging contrast agent.
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Affiliation(s)
- Zhijin Chen
- School of Pharmaceutical Science, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China
| | - Dexin Yu
- Department of Radiology Medicine, Affiliated Qilu Hospital, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China
| | - Shaojie Wang
- School of Chemistry and Chemical Engineering, Shandong University, 27 Shanda Road, 250012, Ji’nan, People’s Republic of China
| | - Na Zhang
- School of Pharmaceutical Science, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China
| | - Chunhong Ma
- Department of Radiology Medicine, Affiliated Qilu Hospital, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China
| | - Zaijun Lu
- School of Chemistry and Chemical Engineering, Shandong University, 27 Shanda Road, 250012, Ji’nan, People’s Republic of China
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42
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Abulrob A, Brunette E, Slinn J, Baumann E, Stanimirovic D. Dynamic Analysis of the Blood-Brain Barrier Disruption in Experimental Stroke Using Time Domain in Vivo Fluorescence Imaging. Mol Imaging 2008. [DOI: 10.2310/7290.2008.00025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The blood-brain barrier (BBB) disruption following cerebral ischemia can be exploited to deliver imaging agents and therapeutics into the brain. The aim of this study was (a) to establish novel in vivo optical imaging methods for longitudinal assessment of the BBB disruption and (b) to assess size selectivity and temporal patterns of the BBB disruption after a transient focal ischemia. The BBB permeability was assessed using in vivo time domain near-infrared optical imaging after contrast enhancement with either free Cy5.5 (1 kDa) or Cy5.5 conjugated with bovine serum albumin (BSA) (67 kDa) in mice subjected to either 60- or 20-minute transient middle cerebral artery occlusion (MCAO) and various times of reperfusion (up to 14 days). In vivo imaging observations were corroborated by ex vivo brain imaging and microscopic analyses of fluorescent tracer extravasation. The in vivo optical contrast enhancement with Cy5.5 was spatially larger than that observed with BSA-Cy5.5. Longitudinal studies after a transient 20-minute MCAO suggested a bilateral BBB disruption, more pronounced in the ipsilateral hemisphere, peaking at day 7 and resolving at day 14 after ischemia. The area differential between the BBB disruption for small and large molecules could potentially be useful as a surrogate imaging marker for assessing perinfarct tissues to which neuroprotective therapies of appropriate sizes could be delivered.
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Affiliation(s)
- Abedelnasser Abulrob
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Eric Brunette
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Jacqueline Slinn
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Ewa Baumann
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Danica Stanimirovic
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
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