Project

Back to overview

Molecular imaging of neutrophil protease-mediated blood-brain barrier impairment and thrombosis after cerebral ischemia

Applicant Klohs Jan
Number 136822
Funding scheme Ambizione
Research institution Institut für Biomedizinische Technik Universität und ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Neurophysiology and Brain Research
Start/End 01.01.2012 - 31.05.2015
Approved amount 599'142.00
Show all

All Disciplines (2)

Discipline
Neurophysiology and Brain Research
Biomedical Engineering

Keywords (6)

stroke; optical imaging; magnetic resonance imaging; blood-brain barrier; thrombosis; neutrophils

Lay Summary (English)

Lead
Lay summary

Stroke poses a massive disease burden, but only few effective therapies exist yet. Intensive research effort has focused on the role of inflammation after cerebral ischemia because inflammation occurs for hours and even days after onset of ischemia, providing an extended window for therapy. However, therapeutic targeting of inflammation is hampered by the fact that processes are dynamic and interact in a complex and often multifaceted way. Techniques that would allow visualizing of such processes non-invasively would facilitate the development of therapies. To date, such techniques for use in experimental models and patients are not yet available.

Neutrophils can exert many different effects in the immune response following tissue injury and repair. Activated neutrophils can secrete substances, which can contribute to the breakdown of tissue barriers like the blood-brain barrier. Furthermore, neutrophils can extrude extracellular traps, which can serve as scaffold for fibrin and hence contribute to the formation of a thrombus. By exerting these actions, neutrophils could contribute to ischemic brain injury. Still, large gaps remain in the understanding on how these actions engage in the evolution of the ischemic injury and how they are involved in blood-brain barrier (BBB) impairment, hemorrhagic transformation (HT) and thrombosis.

The object of the project is to address these questions using non-invasive imaging techniques such as near-infrared fluorescence (NIRF) imaging and magnetic resonance imaging with dedicated imaging probes, experimental models of cerebral ischemia, genetic mouse models and pharmacology to bridge the gap in knowledge on how neutrophils mediate blood-brain barrier impairment, hemorrhagic transformation and thrombosis after focal cerebral ischemia. For this purpose, imaging assays for visualizing neutrophil proteolysis, adhesion and thrombus formation will be developed and validated. The combined use of imaging modalities and multiple imaging probes will enable to investigate several processes relevant for BBB impairment, HT and thrombosis and their interaction in-vivo in a mouse model of cerebral ischemia. Imaging will be employed to test new therapies for application together with thrombolytic therapy with recombinant tissue plasminogen activator and to guide the application of this therapy. The aim is to make thrombolysis safer and more applicable.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Quantitative assessment of microvasculopathy in arcAβ mice with USPIO-enhanced gradient echo MRI.
Klohs Jan, Deistung Andreas, Ielacqua Giovanna, Seuwen Aline, Kindler Diana, Schweser Ferdianand, Vaas Markus, Kipar Anja, Reichenbach Jürgen, Rudin Markus (2016), Quantitative assessment of microvasculopathy in arcAβ mice with USPIO-enhanced gradient echo MRI., in Journal of Cerebral Blood Flow and Metabolism.
Reconstructing cerebrovascular networks under local physiological constraints by integer programming
Rempfler Markus (2015), Reconstructing cerebrovascular networks under local physiological constraints by integer programming, in Medical Imaging Analysis, 00042.
Early alterations in functional connectivity and white matter structure 1 in a transgenic mouse model of cerebral amyloidosis
Grandjean Joanes (2014), Early alterations in functional connectivity and white matter structure 1 in a transgenic mouse model of cerebral amyloidosis, in Journal of Neuroscience, 13780.
Endogenous α-Calcitonin gene-related peptide promotes exercise-induced, physiological heart hypertrophy in mice
Schuler Beat (2014), Endogenous α-Calcitonin gene-related peptide promotes exercise-induced, physiological heart hypertrophy in mice, in Acta Physiologica, 107.
Imaging of cerebrovascular pathology in animal models of Alzheimer`s Disease, Frontiers in Aging Neuroscience
Klohs Jan (2014), Imaging of cerebrovascular pathology in animal models of Alzheimer`s Disease, Frontiers in Aging Neuroscience, in Frontiers Aginging Neuroscience, 32.
Longitudinal Assessment of Amyloid Pathology in Transgenic ArcA beta Mice Using Multi-Parametric Magnetic Resonance Imaging
Klohs Jan, Politano Igna Wojtyna, Deistung Andreas, Grandjean Joanes, Drewek Anna, Dominietto Marco, Keist Ruth, Schweser Ferdinand, Reichenbach Juergen R., Nitsch Roger M., Knuesel Irene, Rudin Markus (2013), Longitudinal Assessment of Amyloid Pathology in Transgenic ArcA beta Mice Using Multi-Parametric Magnetic Resonance Imaging, in PLOS ONE, 8(6), e66097.
Application of cryogenic radiofrequency probes for In vivo phenotyping of mice
Klohs Jan, Seuwen Aline, Schröter Aileen, Marek Daniel, Rudin Markus (2012), Application of cryogenic radiofrequency probes for In vivo phenotyping of mice, in Price William (ed.), 165-183.
Contrast-enhanced magnetic resonance microangiography reveals remodeling of the cerebral microvasculature in transgenic ArcAβ mice
Klohs Jan, Baltes Christof, Princz-Kranz Felicitas, Ratering David, Nitsch Roger M., Knuesel Irène, Rudin Markus (2012), Contrast-enhanced magnetic resonance microangiography reveals remodeling of the cerebral microvasculature in transgenic ArcAβ mice, in Journal of Neuroscience, 32(5), 1705-1713.
Non-invasive optical imaging in rodent models of stroke
Klohs Jan, Non-invasive optical imaging in rodent models of stroke, in Dirnagl Ulrich (ed.).
Post-ischemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke
Spescha Remo, Post-ischemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke, in European Heart Journal.

Collaboration

Group / person Country
Types of collaboration
Kinderspital Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
University of Zurich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
University of Berne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel
Univeristy of Jena Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Froum of Neuroscience, FENS Poster The role of GABAergic transmission in stroke pathology. 02.07.2016 Kopenhagen, Denmark Klohs Jan; Vaas Markus Josef;
8th European-Japanese Cerebrovascular Congress Talk given at a conference novel neuroimaging techniques for vascular pathologies 25.06.2016 Zürich, Switzerland Klohs Jan;
9th International Symposium on Neuroprotection and Neurorepair Talk given at a conference near-infrared fluorescence imaging for non-invasive tracking of the neutrophil response after experimental stroke 19.04.2016 Leipzig, Germany Klohs Jan; Vaas Markus Josef;
European Molecular Imaging Meeting Talk given at a conference novel PET/OA/US/MRI imaging and reporter probes 10.03.2016 Utrecht, Netherlands Klohs Jan;
Seminar series, School of Life Sciences, University of Nottingham Individual talk Non-invasive imaging of the diseased brain: from microstructure to mapping of molecular events 25.11.2015 Nottingham, Great Britain and Northern Ireland Klohs Jan;
Research topics in biomedical Engineering, IBT Zurich Individual talk MR imaging of vascular remodeling in transgenic mouse models of Alzheimer`s disease 27.10.2015 Zurich, Switzerland Klohs Jan;
Hot Topics in Molecular Imaging – TOPIM, 9th Winter conference of the European Society for Molecular Imaging Poster Monitoring the recruitment of neutrophils to infarcted area in a mouse model of transient cerebral ischemia 02.02.2015 Les Houches, France Vaas Markus Josef; Klohs Jan;
ZNZ Symposium Poster Assessment of neutrophil activity after focal cerebral ischemia with imaging 11.09.2014 Zürich, Switzerland Vaas Markus Josef; Klohs Jan;
European molecular imaging meeting EMIM 2014 Poster Monitoring the recruitment of activated neutrophils to the ischemic lesion in a mouse model of transient cerebral ischemia 04.06.2014 Antwerpen, Belgium Klohs Jan; Vaas Markus Josef;
joint annual meeting ISMRM-ESMRMB Poster Age-Dependent Decrease of Capillary Density in ArcAbeta Mouse Model of Cerebral Amyloidosis Detected with Relaxation Rate Shift Index Q Mapping at 9.4T Using a Cryoprobe 10.05.2014 Mailand, Italy Klohs Jan;
8th International Symposium on Neuroprotection Neurorepair Poster Towards monitoring the recruitment of bone marrow-derived neutrophils to infarcted area in a mouse model of transient cerebral ischemia 09.04.2014 Magdeburg, Germany Klohs Jan; Vaas Markus Josef;
ZNZ Symposium Poster Assessment of neutrophil activity after focal cerebral ischemia with imaging 13.09.2013 Zürich, Switzerland Vaas Markus Josef; Klohs Jan;
Congress of the European-Society-of-Cardiology Poster Post-ischemic in vivo p66shc silencing as a therapeutical strategy for ischemia/reperfusion brain injury 31.08.2013 Amsterdam, Netherlands Klohs Jan;
Genetic approaches in Biomedical Research Individual talk Non-invasive imaging of the diseased brain: from microstructure to mapping of molecular events 05.04.2013 Biozentrum University Basel, Switzerland Klohs Jan;
11th international conference on Alzheimer`s and Parkinson`s disease Poster Functional connectivity and fractional anisotropy reveal early impairments in arcAbeta mouse model of Alzheimer´s disease 05.03.2013 Florenz, Italy Klohs Jan;
11th international conference on Alzheimer`s and Parkinson`s disease Talk given at a conference Longitudinal Assessment of Amyloid Pathology in Transgenic ArcAβ Mice Using Multi-parametric Magnetic Resonance Imaging 05.03.2013 Florenz, Italy Klohs Jan;
Photonics West Poster Reconstructing optical parameters from double-integrating-sphere measurements using a genetic algorithm 02.02.2013 San Francisco, United States of America Klohs Jan;
Arbeitsgruppe Lipide und Atherosklerose Poster p66Shc as a novel therapeutical target for ischemia/reperfusion brain injury 04.12.2012 München, Germany Klohs Jan;
European Society for Magnetic Resonance in Medicine B Poster Longitudinal multi-parametric MRI of cerebral amyloidosis in transgenic arcAbeta mice 04.10.2012 Lissabon, Portugal Klohs Jan;
European Society for Magnetic Resonance in Medicine B Talk given at a conference Contrast-enhanced microangiography reveals remodeling of the cerebral microvasculature in transgenic arcAbeta mice 04.10.2012 Lissabon, Portugal Klohs Jan;
Monday Seminar HS2012 Individual talk Non-invasive imaging of the diseased brain: from microstructure to mapping of molecular events 01.10.2012 Zürich, Switzerland Klohs Jan;
forum: imaging, signal analysis and modeling of spreading depolarizations Individual talk MRI phenotyping of genetically engineered mouse models of Alzheimer`s disease 02.08.2012 Berlin, Germany Klohs Jan;
ZNZ and NCCR NEURO JOINT SYMPOSIUM Poster Near-infrared fluorescence imaging for non-invasive assessment of neutrophil activity in a mouse model of stroke 14.06.2012 Zürich, Switzerland Klohs Jan; Vaas Markus Josef;
7th International symposium on neuroprotection and neurorepair Talk given at a conference Contrast-enhanced magnetic resonance microangiography reveals remodeling of the cerebral microvasculature in transgenic arcAbeta mice 02.05.2012 Postdam, Germany Klohs Jan;
Deutsche Physiologische Gesellschaft Poster Endogenous alpha calcitonin gene-related peptide (aCGRP) promotes physiological, exercise-induced cardiac hypertrophy 22.03.2012 Dresden, Germany Klohs Jan;
R&D forum Individual talk Non-invasive imaging of the diseased brain: from microstructure to mapping of molecular events 06.02.2012 CSL Berhing, Bern, Switzerland Klohs Jan;


Communication with the public

Communication Title Media Place Year
New media (web, blogs, podcasts, news feeds etc.) Early warning BPoD - BIOMEDICAL PICTURE OF THE DAY International 2013
New media (web, blogs, podcasts, news feeds etc.) Field Ramps Up "Mini" Mouse MRI Alzheimer Research Forum International 2013
New media (web, blogs, podcasts, news feeds etc.) Silent Vascular Disease May Hasten Dementia Progression Alzheimer Research Forum International 2012

Awards

Title Year
Posterpreis, European molecular imaging meeting EMIM 2014 2014

Associated projects

Number Title Start Funding scheme
179277 Investigating the effects of hypercholesterolemia on neutrophil-mediated thromboinflammation after cerebral ischemia 01.07.2018 Project funding (Div. I-III)

Abstract

Stroke poses a massive disease burden, but only few effective therapies exist yet. Intensive research effort has focused on the role of inflammation after cerebral ischemia because inflammation occurs for hours and even days after onset of ischemia, providing an extended window for therapy. However, therapeutic targeting of inflammation is hampered by the fact that processes are dynamic and interact in a complex and often multifaceted way. Techniques that would allow visualizing of such processes non-invasively would facilitate the development of therapies. To date, such techniques for use in experimental models and patients are not yet available.Neutrophils can exert many different effects in the immune response following tissue injury and repair. Activated neutrophils can secrete substances, which can contribute to the breakdown of tissue barriers like the blood-brain barrier. Furthermore, neutrophils can extrude extracellular traps, which can serve as scaffold for fibrin and hence contribute to the formation of a thrombus. By exerting these actions, neutrophils could contribute to ischemic brain injury. Still, large gaps remain in the understanding on how these actions engage in the evolution of the ischemic injury and how they are involved in blood-brain barrier impairment, hemorrhagic transformation and thrombosis.My proposal focuses on using non-invasive imaging techniques such as near-infrared fluorescence (NIRF) imaging and magnetic resonance imaging (MRI) with dedicated imaging probes, experimental models of cerebral ischemia, genetic mouse models and pharmacology to bridge the gap in knowledge on how neutrophils mediate blood-brain barrier (BBB) impairment, hemorrhagic transformation (HT) and thrombosis after focal cerebral ischemia. For this purpose, imaging assays for visualizing neutrophil proteolysis, adhesion and thrombus formation will be developed and validated. The combined use of imaging modalities and multiple imaging probes will enable to investigate several processes relevant for BBB impairment, HT and thrombosis and their interaction in-vivo in a mouse model of cerebral ischemia. Imaging will be employed to test new therapies for application together with thrombolytic therapy with recombinant tissue plasminogen activator (rtPA) and to guide the application of this therapy. The aim is to make thrombolysis safer and more applicable. Aim 1: Specific molecular imaging of neutrophil elastase and avß3 integrin expression after cerebral ischemia. The hypotheses will be tested if neutrophil elastase and neutrophil adhesion are involved in BBB impairment after cerebral ischemia. The study aims at developing and validating NIRF imaging assays for visualizing non-invasively avß3 integrin expression and neutrophil elastase activity in a mouse model of cerebral ischemia with NIRF imaging. The time course of these processes will be monitored in groups of animals and differences in BBB impairment and ischemic lesion volume after genetic and pharmacological inhibition of neutrophil elastase activity and avß3 integrin expression will be assessed.Aim 2: Imaging of neutrophil-mediated BBB impairment for treatment stratification before thrombolysis with rtPA. The study aims to evaluate neutrophil elastase activity, avß3 expression and matrix metalloproteinase imaging for their capability to predict BBB impairment and HT in a mouse model of cerebral ischemia. More specifically, two hypotheses will be tested: that imaging of neutrophil-mediated BBB impairment can be used to predict the risk of developing HT after thrombolytic therapy and that imaging can be used for treatment stratification prior to thrombolysis. MRI techniques will be used to assess BBB function and outcome before and after thrombolytic therapy. In addition, the question if pharmacological inhibition of neutrophil-mediated BBB impairment can reduce HT and prolong the time window for rtPA treatment will be studied. For this purpose, neutrophil-mediated BBB impairment will be inhibited prior to thrombolysis and the effects on BBB impairment, number of cerebral microbleeds and hemorrhages and lesion volume will be assessed with MRI and histology. Aim 3: Imaging of neutrophil-mediated thrombosis after cerebral ischemia. The hypotheses will be tested that neutrophils are involved in the formation of microthrombi after cerebral ischemia and that this process contributes to the evolution of postischemic blood flow obstruction and promotes the progression of ischemic lesion. The aim of the study is to use NIRF probes and a fibrin-targeted MRI contrast agent to image neutrophil elastase activity, avß3 expression and thrombus formation with NIRF imaging and MRI in-vivo. The effect on cerebral blood flow and lesion volume will be monitored with MRI. Furthermore, the question whether mice which have a high degree of microthrombi will benefit from anti-coagulant therapy will be studied by abolishing local thrombosis and improving blood flow.
-