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Serafini E, Corti A, Gallo D, Chiastra C, Li XC, Casarin S. An agent-based model of cardiac allograft vasculopathy: toward a better understanding of chronic rejection dynamics. Front Bioeng Biotechnol 2023; 11:1190409. [PMID: 37771577 PMCID: PMC10523786 DOI: 10.3389/fbioe.2023.1190409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/17/2023] [Indexed: 09/30/2023] Open
Abstract
Cardiac allograft vasculopathy (CAV) is a coronary artery disease affecting 50% of heart transplant (HTx) recipients, and it is the major cause of graft loss. CAV is driven by the interplay of immunological and non-immunological factors, setting off a cascade of events promoting endothelial damage and vascular dysfunction. The etiology and evolution of tissue pathology are largely unknown, making disease management challenging. So far, in vivo models, mostly mouse-based, have been widely used to study CAV, but they are resource-consuming, pose many ethical issues, and allow limited investigation of time points and important biomechanical measurements. Recently, agent-based models (ABMs) proved to be valid computational tools for deciphering mechanobiological mechanisms driving vascular adaptation processes at the cell/tissue level, augmenting cost-effective in vivo lab-based experiments, at the same time guaranteeing richness in observation time points and low consumption of resources. We hypothesize that integrating ABMs with lab-based experiments can aid in vivo research by overcoming those limitations. Accordingly, this work proposes a bidimensional ABM of CAV in a mouse coronary artery cross-section, simulating the arterial wall response to two distinct stimuli: inflammation and hemodynamic disturbances, the latter considered in terms of low wall shear stress (WSS). These stimuli trigger i) inflammatory cell activation and ii) exacerbated vascular cell activities. Moreover, an extensive analysis was performed to investigate the ABM sensitivity to the driving parameters and inputs and gain insights into the ABM working mechanisms. The ABM was able to effectively replicate a 4-week CAV initiation and progression, characterized by lumen area decrease due to progressive intimal thickening in regions exposed to high inflammation and low WSS. Moreover, the parameter and input sensitivity analysis highlighted that the inflammatory-related events rather than the WSS predominantly drive CAV, corroborating the inflammatory nature of the vasculopathy. The proof-of-concept model proposed herein demonstrated its potential in deepening the pathology knowledge and supporting the in vivo analysis of CAV.
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Affiliation(s)
- Elisa Serafini
- PolitoMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
- LaSIE, UMR 7356 CNRS, La Rochelle Université, La Rochelle, France
- Center for Precision Surgery, Houston Methodist Research Institute, Houston, TX, United States
| | - Anna Corti
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Milan, Italy
| | - Diego Gallo
- PolitoMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Claudio Chiastra
- PolitoMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Xian C. Li
- Immunobiology and Transplant Science Center, Houston Methodist Hospital, Houston, TX, United States
- Department of Surgery, Weill Cornell Medical College of Cornell University, New York, NY, United States
- Department of Surgery, Houston Methodist Hospital, Houston, TX, United States
| | - Stefano Casarin
- LaSIE, UMR 7356 CNRS, La Rochelle Université, La Rochelle, France
- Center for Precision Surgery, Houston Methodist Research Institute, Houston, TX, United States
- Department of Surgery, Houston Methodist Hospital, Houston, TX, United States
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2
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Davis S, Karali A, Zekonyte J, Roldo M, Blunn G. Development of a method to investigate strain distribution across the cartilage-bone interface in guinea pig model of spontaneous osteoarthritis using lab-based contrast enhanced X-ray-computed tomography and digital volume correlation. J Mech Behav Biomed Mater 2023; 144:105999. [PMID: 37406483 DOI: 10.1016/j.jmbbm.2023.105999] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/23/2023] [Accepted: 06/28/2023] [Indexed: 07/07/2023]
Abstract
OBJECTIVE Strain changes at the cartilage-bone interface play a crucial role in osteoarthritis (OA) development. Contrast-Enhanced X-ray Computed Tomography (CECT) and Digital Volume Correlation (DVC) can measure 3D strain changes at the osteochondral interface. Using lab-based CT systems it is often difficult to visualise soft tissues such as articular cartilage without staining to enhance contrast. Contrast-Enhancing Staining Agents (CESAs), such as Phosphotungstic Acid (PTA) in 70% ethanol, can cause tissue shrinkage and alter tissue mechanics. The aims of this study were, firstly, to assess changes to the mechanical properties of osteochondral tissue after staining with a PTA/PBS solution, and secondly, to visualise articular cartilage during loading and with CECT imaging in order to compare strain across the interface in both healthy and OA joints using DVC. DESIGN Nanoindentation was used to assess changes to mechanical properties in articular cartilage and subchondral bone before and after staining. Hindlimbs from Dunkin-Hartley guinea pigs were stained with 1% PTA/PBS at room temperature for 6 days. Two consecutive CECT datasets were acquired for DVC error analysis. In-situ compression with a load corresponding to 2x body weight was applied, the specimen was re-imaged, and DVC was performed between the pre- and post-load tomograms. RESULTS Nanoindentation before and after PTA/PBS staining showed similar cartilage stiffness (p < 0.05), however, staining significantly decreased the stiffness of subchondral bone (∼9-fold; p = 0.0012). In severe OA specimens, third principal/compressive (εp3) strain was 141.7% higher and shear strain (γ) was 98.2% higher in tibial articular cartilage compared to non-OA (2 - month) specimens. A 23.1% increase in third principal stain strain and a 54.5% significant increase in the shear (γ) strain (p = 0.0027) was transferred into the mineralised regions of calcified cartilage and subchondral bone in severe OA specimens. CONCLUSIONS These results indicate the suitability of PTA in PBS as a contrast agent for the visualisation of cartilage during CECT imaging and allowed DVC computation of strain across the cartilage-bone interface. However, further research is needed to address the reduction in stiffness of subchondral bone after incubation in PBS.
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Affiliation(s)
- Sarah Davis
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK; School of Mechanical and Design Engineering, University of Portsmouth, PO1 3DJ, UK.
| | - Aikaterina Karali
- School of Mechanical and Design Engineering, University of Portsmouth, PO1 3DJ, UK
| | - Jurgita Zekonyte
- School of Mechanical and Design Engineering, University of Portsmouth, PO1 3DJ, UK
| | - Marta Roldo
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - Gordon Blunn
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK
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Taphorn K, Busse M, Brantl J, Günther B, Diaz A, Holler M, Dierolf M, Mayr D, Pfeiffer F, Herzen J. X-ray Stain Localization with Near-Field Ptychographic Computed Tomography. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201723. [PMID: 35748171 PMCID: PMC9404393 DOI: 10.1002/advs.202201723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Although X-ray contrast agents offer specific characteristics in terms of targeting and attenuation, their accumulation in the tissue on a cellular level is usually not known and difficult to access, as it requires high resolution and sensitivity. Here, quantitative near-field ptychographic X-ray computed tomography is demonstrated to assess the location of X-ray stains at a resolution sufficient to identify intracellular structures by means of a basis material decomposition. On the example of two different X-ray stains, the nonspecific iodine potassium iodide, and eosin Y, which mostly interacts with proteins and peptides in the cell cytoplasm, the distribution of the stains within the cells in murine kidney samples is assessed and compared to unstained samples with similar structural features. Quantitative nanoscopic stain concentrations are in good agreement with dual-energy micro computed tomography measurements, the state-of-the-art modality for material-selective imaging. The presented approach can be applied to a variety of X-ray stains advancing the development of X-ray contrast agents.
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Affiliation(s)
- Kirsten Taphorn
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
| | - Madleen Busse
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
| | - Johannes Brantl
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
| | - Benedikt Günther
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
| | - Ana Diaz
- Paul Scherrer InstituteVilligen5232Switzerland
| | | | - Martin Dierolf
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
| | - Doris Mayr
- Institute of PathologyLudwig‐Maximilians‐University80337MunichGermany
| | - Franz Pfeiffer
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
- Department of Diagnostic and Interventional RadiologySchool of Medicine & Klinikum rechts der IsarTechnical University of Munich81675MünchenGermany
- Institute for Advanced StudyTechnical University of Munich85748GarchingGermany
| | - Julia Herzen
- Chair of Biomedical PhysicsDepartment of PhysicsSchool of Natural SciencesTechnical University of Munich85748GarchingGermany
- Munich Institute of Biomedical Engineering (MIBE)Technical University of Munich85748GarchingGermany
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4
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Matula J, Polakova V, Salplachta J, Tesarova M, Zikmund T, Kaucka M, Adameyko I, Kaiser J. Resolving complex cartilage structures in developmental biology via deep learning-based automatic segmentation of X-ray computed microtomography images. Sci Rep 2022; 12:8728. [PMID: 35610276 PMCID: PMC9130254 DOI: 10.1038/s41598-022-12329-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/03/2022] [Indexed: 11/18/2022] Open
Abstract
The complex shape of embryonic cartilage represents a true challenge for phenotyping and basic understanding of skeletal development. X-ray computed microtomography (μCT) enables inspecting relevant tissues in all three dimensions; however, most 3D models are still created by manual segmentation, which is a time-consuming and tedious task. In this work, we utilised a convolutional neural network (CNN) to automatically segment the most complex cartilaginous system represented by the developing nasal capsule. The main challenges of this task stem from the large size of the image data (over a thousand pixels in each dimension) and a relatively small training database, including genetically modified mouse embryos, where the phenotype of the analysed structures differs from the norm. We propose a CNN-based segmentation model optimised for the large image size that we trained using a unique manually annotated database. The segmentation model was able to segment the cartilaginous nasal capsule with a median accuracy of 84.44% (Dice coefficient). The time necessary for segmentation of new samples shortened from approximately 8 h needed for manual segmentation to mere 130 s per sample. This will greatly accelerate the throughput of μCT analysis of cartilaginous skeletal elements in animal models of developmental diseases.
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Affiliation(s)
- Jan Matula
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic
| | - Veronika Polakova
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic
| | - Jakub Salplachta
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic
| | - Marketa Tesarova
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic
| | - Tomas Zikmund
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic
| | - Marketa Kaucka
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str.2, 24306, Ploen, Germany
| | - Igor Adameyko
- Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, 17165, Stockholm, Sweden
| | - Jozef Kaiser
- Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno, 61200, Czech Republic.
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5
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Baroi S, Czernik PJ, Chougule A, Griffin PR, Lecka-Czernik B. PPARG in osteocytes controls sclerostin expression, bone mass, marrow adiposity and mediates TZD-induced bone loss. Bone 2021; 147:115913. [PMID: 33722775 PMCID: PMC8076091 DOI: 10.1016/j.bone.2021.115913] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/05/2021] [Accepted: 03/06/2021] [Indexed: 01/07/2023]
Abstract
The peroxisome proliferator activated receptor gamma (PPARG) nuclear receptor regulates energy metabolism and insulin sensitivity. In this study, we present novel evidence for an essential role of PPARG in the regulation of osteocyte function, and support for the emerging concept of the conjunction between regulation of energy metabolism and bone mass. We report that PPARG is essential for sclerostin production, a recently approved target to treat osteoporosis. Our mouse model of osteocyte-specific PPARG deletion (Dmp1CrePparγflfl or γOTKO) is characterized with increased bone mass and reduced bone marrow adiposity, which is consistent with upregulation of WNT signaling and increased bone forming activity of endosteal osteoblasts. An analysis of osteocytes derived from γOTKO and control mice showed an excellent correlation between PPARG and SOST/sclerostin at the transcript and protein levels. The 8 kb sequence upstream of Sost gene transcription start site possesses multiple PPARG binding elements (PPREs) with at least two of them binding PPARG with dynamics reflecting its activation with full agonist rosiglitazone and correlating with increased levels of Sost transcript and sclerostin protein expression (Pearson's r = 0.991, p = 0.001). Older γOTKO female mice are largely protected from TZD-induced bone loss providing proof of concept that PPARG in osteocytes can be pharmacologically targeted. These findings demonstrate that transcriptional activities of PPARG are essential for sclerostin expression in osteocytes and support consideration of targeting PPARG activities with selective modulators to treat osteoporosis.
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Affiliation(s)
- Sudipta Baroi
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Piotr J Czernik
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Amit Chougule
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Patrick R Griffin
- The Scripps Research Institute, Jupiter, FL, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Beata Lecka-Czernik
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Department of Physiology and Pharmacology, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America.
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6
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Doost A, Arnolda L. Iodine staining outperforms phosphotungstic acid in high-resolution micro-CT scanning of post-natal mice cardiac structures. J Med Imaging (Bellingham) 2021; 8:027001. [PMID: 33778096 DOI: 10.1117/1.jmi.8.2.027001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/12/2021] [Indexed: 01/21/2023] Open
Abstract
Purpose: Micro-computed tomography (micro-CT) scan provides high-resolution three-dimensional images of mineralized tissues in small animal models. Contrast enhancement is essential to visualize non-mineralized tissues with micro-CT scan. We attempted to compare the two most common contrast agents to stain and image mouse cardiac structures. Approach: Ex-vivo micro-CT scan images of the mouse hearts were obtained following staining by potassium iodide or phosphotungstic acid (PTA). PTA-stained samples were imaged after various durations following staining (14 days, 25 days, 187 days, and 780 days), whereas iodine-stained samples were imaged after 72 hours. We compared median staining intensity between PTA and iodine at 0.1-mm intervals from the edge using the Mann Whitney test with correction for multiple comparisons. Results: Sixty post-natal mice hearts were stained with either PTA or iodine and imaged using micro-CT scan. Iodine proved to be faster and more uniform in complete enhancement of cardiac tissue in as short as 72 h, whereas PTA required a significantly longer time period to penetrate mouse cardiac structure ( > 150 days ). Median staining intensity with iodine was strongly higher than that with PTA from 0.1- to 1.5-mm distance from the epicardial edge (2-tailed P value < 0.01 or lower throughout). Conclusions: Iodine-stained soft tissue imaging by micro-CT scan provides a non-destructive, efficient, and accurate visualization tool for anatomical analysis of animal heart models of human cardiovascular conditions. Iodine is more efficient compared to PTA to achieve complete murine myocardial staining in a significantly shorter time period.
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Affiliation(s)
- Ata Doost
- Australian National University Medical School, Canberra, Australian Capital Territory, Australia.,Fiona Stanley Hospital, Cardiology Department, Murdoch, Western Australia, Australia
| | - Leonard Arnolda
- Australian National University Medical School, Canberra, Australian Capital Territory, Australia.,University of Wollongong, Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia
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Willemink MJ, Varga-Szemes A, Schoepf UJ, Codari M, Nieman K, Fleischmann D, Mastrodicasa D. Emerging methods for the characterization of ischemic heart disease: ultrafast Doppler angiography, micro-CT, photon-counting CT, novel MRI and PET techniques, and artificial intelligence. Eur Radiol Exp 2021; 5:12. [PMID: 33763754 PMCID: PMC7991013 DOI: 10.1186/s41747-021-00207-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/22/2021] [Indexed: 12/24/2022] Open
Abstract
After an ischemic event, disruptive changes in the healthy myocardium may gradually develop and may ultimately turn into fibrotic scar. While these structural changes have been described by conventional imaging modalities mostly on a macroscopic scale-i.e., late gadolinium enhancement at magnetic resonance imaging (MRI)-in recent years, novel imaging methods have shown the potential to unveil an even more detailed picture of the postischemic myocardial phenomena. These new methods may bring advances in the understanding of ischemic heart disease with potential major changes in the current clinical practice. In this review article, we provide an overview of the emerging methods for the non-invasive characterization of ischemic heart disease, including coronary ultrafast Doppler angiography, photon-counting computed tomography (CT), micro-CT (for preclinical studies), low-field and ultrahigh-field MRI, and 11C-methionine positron emission tomography. In addition, we discuss new opportunities brought by artificial intelligence, while addressing promising future scenarios and the challenges for the application of artificial intelligence in the field of cardiac imaging.
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Affiliation(s)
- Martin J. Willemink
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA
| | - Akos Varga-Szemes
- grid.259828.c0000 0001 2189 3475Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC USA
| | - U. Joseph Schoepf
- grid.259828.c0000 0001 2189 3475Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC USA
| | - Marina Codari
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA
| | - Koen Nieman
- grid.168010.e0000000419368956Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA USA ,Stanford Cardiovascular Institute, Stanford, CA 94305 USA
| | - Dominik Fleischmann
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA ,Stanford Cardiovascular Institute, Stanford, CA 94305 USA
| | - Domenico Mastrodicasa
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94035, USA. .,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA.
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8
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Leyssens L, Pestiaux C, Kerckhofs G. A Review of Ex Vivo X-ray Microfocus Computed Tomography-Based Characterization of the Cardiovascular System. Int J Mol Sci 2021; 22:3263. [PMID: 33806852 PMCID: PMC8004599 DOI: 10.3390/ijms22063263] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/27/2022] Open
Abstract
Cardiovascular malformations and diseases are common but complex and often not yet fully understood. To better understand the effects of structural and microstructural changes of the heart and the vasculature on their proper functioning, a detailed characterization of the microstructure is crucial. In vivo imaging approaches are noninvasive and allow visualizing the heart and the vasculature in 3D. However, their spatial image resolution is often too limited for microstructural analyses, and hence, ex vivo imaging is preferred for this purpose. Ex vivo X-ray microfocus computed tomography (microCT) is a rapidly emerging high-resolution 3D structural imaging technique often used for the assessment of calcified tissues. Contrast-enhanced microCT (CE-CT) or phase-contrast microCT (PC-CT) improve this technique by additionally allowing the distinction of different low X-ray-absorbing soft tissues. In this review, we present the strengths of ex vivo microCT, CE-CT and PC-CT for quantitative 3D imaging of the structure and/or microstructure of the heart, the vasculature and their substructures in healthy and diseased state. We also discuss their current limitations, mainly with regard to the contrasting methods and the tissue preparation.
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Affiliation(s)
- Lisa Leyssens
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
| | - Camille Pestiaux
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
| | - Greet Kerckhofs
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
- Department of Materials Engineering, Katholieke Universiteit Leuven, 3001 Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
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9
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Chisena RS, Sengenberger J, Shih AJ, Gurm H. Novel preclinical method for evaluating the efficacy of a percutaneous treatment in human ex vivo calcified plaque. Med Biol Eng Comput 2021; 59:799-811. [PMID: 33710527 DOI: 10.1007/s11517-021-02334-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 02/03/2021] [Indexed: 11/28/2022]
Abstract
The lack of suitable atherosclerotic calcification models and testing strategies inhibits preclinical efficacy testing of existing and novel percutaneous devices. The goal of this study is to develop a preclinical testing method for quantitatively and qualitatively evaluating the efficacy of noncompliant balloon angioplasty (NC BA) treatment in human ex vivo calcified plaque (CP). NC BA using a 3- and 4-mm diameter balloon was performed on an ex vivo tibial calcified vessel obtained from an amputation. Three-dimensional microcomputed tomography (μ-CT) imaging was performed pre- and post-BA to compare crack density in the CP. Comparing the pre- and posttreatment three-dimensional μ-CT images showed a glass-like cracking that occurred in the CP due to the BA procedure. Expansion of the 3-mm balloon showed little tissue deformation and no CP cracking. Although expansion of the 4-mm balloon occurred nonuniformly along balloon length and across the perpendicular projections, the balloon generated cracking throughout the CP, which allowed the surrounding elastic tissue to be dilated. This combined X-ray microscopy and μ-CT technique is a useful preclinical tool for quantifying the efficacy of percutaneous treatments for CP. Because of its nondestructive nature, the CP structure can be visualized pre- and posttreatment to determine the treatment effect.
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Affiliation(s)
- Robert S Chisena
- Department of Mechanical Engineering, University of Michigan at Ann Arbor, 2350 Hayward St, Ann Arbor, MI, 48109, USA.
| | - Jordan Sengenberger
- Department of Biomedical Engineering, University of Michigan at Ann Arbor, 2200 Bonisteel Blvd, Ann Arbor, MI, 48109, USA
| | - Albert J Shih
- Department of Mechanical Engineering, University of Michigan at Ann Arbor, 2350 Hayward St, Ann Arbor, MI, 48109, USA
| | - Hitinder Gurm
- Department of Internal Medicine, University of Michigan Health System at Ann Arbor, 1500 E Medical Center Dr, Ann Arbor, MI, 48109, USA
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10
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Matula J, Tesarova M, Zikmund T, Kaucka M, Adameyko I, Kaiser J. X-ray microtomography-based atlas of mouse cranial development. Gigascience 2021; 10:giab012. [PMID: 33677535 PMCID: PMC7936920 DOI: 10.1093/gigascience/giab012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/21/2020] [Accepted: 02/02/2021] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND X-ray microtomography (μCT) has become an invaluable tool for non-destructive analysis of biological samples in the field of developmental biology. Mouse embryos are a typical model for investigation of human developmental diseases. By obtaining 3D high-resolution scans of the mouse embryo heads, we gain valuable morphological information about the structures prominent in the development of future face, brain, and sensory organs. The development of facial skeleton tracked in these μCT data provides a valuable background for further studies of congenital craniofacial diseases and normal development. FINDINGS In this work, reusable tomographic data from 7 full 3D scans of mouse embryo heads are presented and made publicly available. The ages of these embryos range from E12.5 to E18.5. The samples were stained by phosphotungstic acid prior to scanning, which greatly enhanced the contrast of various tissues in the reconstructed images and enabled precise segmentation. The images were obtained on a laboratory-based μCT system. Furthermore, we provide manually segmented masks of mesenchymal condensations (for E12.5 and E13.5) and cartilage present in the nasal capsule of the scanned embryos. CONCLUSION We present a comprehensive dataset of X-ray 3D computed tomography images of the developing mouse head with high-quality manual segmentation masks of cartilaginous nasal capsules. The provided μCT images can be used for studying any other major structure within the developing mouse heads. The high quality of the manually segmented models of nasal capsules may be instrumental to understanding the complex process of the development of the face in a mouse model.
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Affiliation(s)
- Jan Matula
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 61200, Czech Republic
| | - Marketa Tesarova
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 61200, Czech Republic
| | - Tomas Zikmund
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 61200, Czech Republic
| | - Marketa Kaucka
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, Plön, 24306, Germany
- Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Igor Adameyko
- Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Jozef Kaiser
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 61200, Czech Republic
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11
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X-ray Micro-Computed Tomography: An Emerging Technology to Analyze Vascular Calcification in Animal Models. Int J Mol Sci 2020; 21:ijms21124538. [PMID: 32630604 PMCID: PMC7352990 DOI: 10.3390/ijms21124538] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/16/2020] [Accepted: 06/19/2020] [Indexed: 12/15/2022] Open
Abstract
Vascular calcification describes the formation of mineralized tissue within the blood vessel wall, and it is highly associated with increased cardiovascular morbidity and mortality in patients with chronic kidney disease, diabetes, and atherosclerosis. In this article, we briefly review different rodent models used to study vascular calcification in vivo, and critically assess the strengths and weaknesses of the current techniques used to analyze and quantify calcification in these models, namely 2-D histology and the o-cresolphthalein assay. In light of this, we examine X-ray micro-computed tomography (µCT) as an emerging complementary tool for the analysis of vascular calcification in animal models. We demonstrate that this non-destructive technique allows us to simultaneously quantify and localize calcification in an intact vessel in 3-D, and we consider recent advances in µCT sample preparation techniques. This review also discusses the potential to combine 3-D µCT analyses with subsequent 2-D histological, immunohistochemical, and proteomic approaches in correlative microscopy workflows to obtain rich, multifaceted information on calcification volume, calcification load, and signaling mechanisms from within the same arterial segment. In conclusion we briefly discuss the potential use of µCT to visualize and measure vascular calcification in vivo in real-time.
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12
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Ethanol fixation method for heart and lung imaging in micro-CT. Jpn J Radiol 2019; 37:500-510. [DOI: 10.1007/s11604-019-00830-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/08/2019] [Indexed: 10/27/2022]
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13
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3D vessel-wall virtual histology of whole-body perfused mice using a novel heavy element stain. Sci Rep 2019; 9:698. [PMID: 30679558 PMCID: PMC6345940 DOI: 10.1038/s41598-018-36905-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/23/2018] [Indexed: 01/17/2023] Open
Abstract
Virtual histology – utilizing high-resolution three-dimensional imaging – is becoming readily available. Micro-computed tomography (micro-CT) is widely available and is often coupled with x-ray attenuating histological stains that mark specific tissue components for 3D virtual histology. In this study we describe a new tri-element x-ray attenuating stain and perfusion protocol that provides micro-CT contrast of the entire vasculature of an intact mouse. The stain – derived from an established histology stain (Verhoeff’s) – is modified to enable perfusion through the vasculature; the attenuating elements of the stain are iodine, aluminum, and iron. After a 30-minute perfusion through the vasculature (10-minute flushing with detergent-containing saline followed by 15-minute perfusion with the stain and a final 5-minute saline flush), animals are scanned using micro-CT. We demonstrate that the new staining protocol enables sharp delineation of the vessel walls in three dimensions over the whole body; corresponding histological analysis verified that the CT stain is localized primarily in the endothelial cells and media of large arteries and the endothelium of smaller vessels, such as the coronaries. The rapid perfusion and scanning protocol ensured that all tissues are available for further analysis via higher resolution CT of smaller sections or traditional histological sectioning.
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14
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Faight E, Verdelis K, Ahearn JM, Shields KJ. 3D MicroCT spatial and temporal characterization of thoracic aorta perivascular adipose tissue and plaque volumes in the ApoE-/- mouse model. Adipocyte 2018; 7:156-165. [PMID: 29956579 DOI: 10.1080/21623945.2018.1493900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Perivascular adipose tissue (PVAT) influences vascular function and pathology. We present a protocol using micro-computed tomography (microCT), a novel imaging technique typically used for hard biological tissue, to characterize the temporal and spatial development of aorta PVAT and luminal plaque soft tissue. Apolipoprotein E deficient (ApoE) and C57Bl/6J (control) mice were fed a high fat western diet up to 30 weeks. 3D microCT reconstructions were used to quantify: 1) vascular wall volume, a surrogate measure of remodeling, was greater in ApoE, 2) aorta PVAT volume was reduced in ApoE, 3) plaque volumes increased over time in ApoE, 4) plaque development co-localized with luminal ostia, origins of branching arteries, which traveled through areas of greatest PVAT volume, 5) qualitatively, the same arteries showed evidence of increased tortuosity in ApoE. This study reflects the potential of microCT analyses to assess vascular wall, PVAT and arterial trajectory modifications in relevant animal models. Abbreviations: PVAT: perivascular adipose tissue; ApoE: apolipoprotein E deficient mouse strain; Control: C57Bl/6J mouse strain; PTA: 0.3% phosphotungstic acid; microCT: micro-computed tomography; CV: cardiovascular; CVD: cardiovascular disease; IQR: interquartile range; PPARγ: peroxisome proliferator activated receptor - gamma; VV: vasa vasorum; 3D: three dimensional.
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Affiliation(s)
- Erin Faight
- Lupus Center of Excellence, Autoimmunity Institute, Department of Medicine, Allegheny Health Network, Pittsburgh, PA, USA
| | - Kostas Verdelis
- Division of Endodontics at the Department of Restorative Dentistry and Comprehensive Care and the Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph M. Ahearn
- Lupus Center of Excellence, Autoimmunity Institute, Department of Medicine, Allegheny Health Network, Pittsburgh, PA, USA
| | - Kelly J. Shields
- Lupus Center of Excellence, Autoimmunity Institute, Department of Medicine, Allegheny Health Network, Pittsburgh, PA, USA
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15
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Correlative Detection of Isolated Single and Multi-Cellular Calcifications in the Internal Elastic Lamina of Human Coronary Artery Samples. Sci Rep 2018; 8:10978. [PMID: 30030502 PMCID: PMC6054664 DOI: 10.1038/s41598-018-29379-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/26/2018] [Indexed: 01/05/2023] Open
Abstract
Histopathology protocols often require sectioning and processing of numerous microscopy slides to survey a sample. Trade-offs between workload and sampling density means that small features can be missed. Aiming to reduce the workload of routine histology protocols and the concern over missed pathology in skipped sections, we developed a prototype x-ray tomographic scanner dedicated to rapid scouting and identification of regions of interest in pathology specimens, thereby allowing targeted histopathology analysis to replace blanket searches. In coronary artery samples of a deceased HIV patient, the scanner, called Tomopath, obtained depth-resolved cross-sectional images at 15 µm resolution in a 15-minute scan, which guided the subsequent histological sectioning and microscopy. When compared to a commercial tabletop micro-CT scanner, the prototype provided several-fold contrast-to-noise ratio in 1/11th the scan time. Correlated tomographic and histological images revealed two types of micro calcifications: scattered loose calcifications typically found in atherosclerotic lesions; isolated focal calcifications in one or several cells in the internal elastic lamina and occasionally in the tunica media, which we speculate were the initiation of medial calcification linked to kidney disease, but rarely detected at this early stage due to their similarity to particle contaminants introduced during histological processing, if not for the evidence from the tomography scan prior to sectioning. Thus, in addition to its utility as a scouting tool, in this study it provided complementary information to histological microscopy. Overall, the prototype scanner represents a step toward a dedicated scouting and complementary imaging tool for routine use in pathology labs.
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16
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Chaurand P, Liu W, Borschneck D, Levard C, Auffan M, Paul E, Collin B, Kieffer I, Lanone S, Rose J, Perrin J. Multi-scale X-ray computed tomography to detect and localize metal-based nanomaterials in lung tissues of in vivo exposed mice. Sci Rep 2018. [PMID: 29535369 PMCID: PMC5849692 DOI: 10.1038/s41598-018-21862-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO2-NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in a correlative approach: histological observations, 2D chemical mapping and speciation analysis were performed for an unambiguous detection of NMs. This original methodological approach was developed following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO2-NMs within the entire lung lobe (using large field-of-view micro-CT) and (ii) the detection of CeO2-NMs down to the individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).
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Affiliation(s)
- Perrine Chaurand
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France. .,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France.
| | - Wei Liu
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Daniel Borschneck
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Clément Levard
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Mélanie Auffan
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Emmanuel Paul
- INSERM, Equipe 04, U955, Creteil, France.,Univ Paris Est Creteil, IMRB, Fac Med, DHU A TVB, Creteil, France
| | - Blanche Collin
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Isabelle Kieffer
- OSUG-FAME, UMS 832 CNRS-Univ. Grenoble Alpes, F-38041, Grenoble, France
| | - Sophie Lanone
- INSERM, Equipe 04, U955, Creteil, France.,Univ Paris Est Creteil, IMRB, Fac Med, DHU A TVB, Creteil, France
| | - Jérôme Rose
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS-Duke University, Aix en Provence, France
| | - Jeanne Perrin
- Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.,Univ Avignon, Inst Mediterraneen Biodiversite & Ecol Marine & C, Aix Marseille Univ, CNRS, IRD, Marseille, France.,AP HM La Conception, CECOS, Lab Reprod Biol, Dept Gynecol Obstet & Reprod Med, Pole Femmes Parents Enfants, Marseille, France
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17
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Epah J, Pálfi K, Dienst FL, Malacarne PF, Bremer R, Salamon M, Kumar S, Jo H, Schürmann C, Brandes RP. 3D Imaging and Quantitative Analysis of Vascular Networks: A Comparison of Ultramicroscopy and Micro-Computed Tomography. Theranostics 2018; 8:2117-2133. [PMID: 29721067 PMCID: PMC5928875 DOI: 10.7150/thno.22610] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/30/2018] [Indexed: 12/18/2022] Open
Abstract
Rationale: Classic histology is the gold standard for vascular network imaging and analysis. The method however is laborious and prone to artefacts. Here, the suitability of ultramicroscopy (UM) and micro-computed tomography (CT) was studied to establish potential alternatives to histology. Methods: The vasculature of murine organs (kidney, heart and atherosclerotic carotid arteries) was visualized using conventional 2D microscopy, 3D light sheet ultramicroscopy (UM) and micro-CT. Moreover, spheroid-based human endothelial cell vessel formation in mice was quantified. Fluorescently labeled Isolectin GS-IB4 A647 was used for in vivo labeling of vasculature for UM analysis, and analyses were performed ex vivo after sample preparation. For CT imaging, animals were perfused postmortem with radiopaque contrast agent. Results: Using UM imaging, 3D vascular network information could be obtained in samples of animals receiving in vivo injection of the fluorescently labeled Isolectin GS-IB4. Resolution was sufficient to measure single endothelial cell integration into capillaries in the spheroid-based matrigel plug assay. Because of the selective staining of the endothelium, imaging of larger vessels yielded less favorable results. Using micro-CT or even nano-CT, imaging of capillaries was impossible due to insufficient X-ray absorption and thus insufficient signal-to-noise ratio. Identification of lumen in murine arteries using micro-CT was in contrast superior to UM. Conclusion: UM and micro-CT are two complementary techniques. Whereas UM is ideal for imaging and especially quantifying capillary networks and arterioles, larger vascular structures are easier and faster to quantify and visualize using micro-CT. 3D information of both techniques is superior to 2D histology. UM and micro-CT together may open a new field of clinical pathology diagnosis.
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18
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Three-dimensional virtual histology enabled through cytoplasm-specific X-ray stain for microscopic and nanoscopic computed tomography. Proc Natl Acad Sci U S A 2018; 115:2293-2298. [PMID: 29463748 DOI: 10.1073/pnas.1720862115] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Many histological methods require staining of the cytoplasm, which provides instrumental details for diagnosis. One major limitation is the production of 2D images obtained by destructive preparation of 3D tissue samples. X-ray absorption micro- and nanocomputed tomography (microCT and nanoCT) allows for a nondestructive investigation of a 3D tissue sample, and thus aids to determine regions of interest for further histological examinations. However, application of microCT and nanoCT to biological samples (e.g., biopsies) is limited by the missing contrast within soft tissue, which is important to visualize morphological details. We describe an eosin-based preparation overcoming the challenges of contrast enhancement and selectivity for certain tissues. The eosin-based staining protocol is suitable for whole-organ staining, which then enables high-resolution microCT imaging of whole organs and nanoCT imaging of smaller tissue pieces retrieved from the original sample. Our results demonstrate suitability of the eosin-based staining method for diagnostic screening of 3D tissue samples without impeding further diagnostics through histological methods.
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19
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Zeller-Plumhoff B, Roose T, Clough GF, Schneider P. Image-based modelling of skeletal muscle oxygenation. J R Soc Interface 2017; 14:rsif.2016.0992. [PMID: 28202595 DOI: 10.1098/rsif.2016.0992] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/25/2017] [Indexed: 12/12/2022] Open
Abstract
The supply of oxygen in sufficient quantity is vital for the correct functioning of all organs in the human body, in particular for skeletal muscle during exercise. Disease is often associated with both an inhibition of the microvascular supply capability and is thought to relate to changes in the structure of blood vessel networks. Different methods exist to investigate the influence of the microvascular structure on tissue oxygenation, varying over a range of application areas, i.e. biological in vivo and in vitro experiments, imaging and mathematical modelling. Ideally, all of these methods should be combined within the same framework in order to fully understand the processes involved. This review discusses the mathematical models of skeletal muscle oxygenation currently available that are based upon images taken of the muscle microvasculature in vivo and ex vivo Imaging systems suitable for capturing the blood vessel networks are discussed and respective contrasting methods presented. The review further informs the association between anatomical characteristics in health and disease. With this review we give the reader a tool to understand and establish the workflow of developing an image-based model of skeletal muscle oxygenation. Finally, we give an outlook for improvements needed for measurements and imaging techniques to adequately investigate the microvascular capability for oxygen exchange.
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Affiliation(s)
- B Zeller-Plumhoff
- Helmholtz-Zentrum für Material- und Küstenforschung, Geesthacht, Germany .,Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - T Roose
- Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - G F Clough
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - P Schneider
- Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
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20
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High-contrast X-ray micro-radiography and micro-CT of ex-vivo soft tissue murine organs utilizing ethanol fixation and large area photon-counting detector. Sci Rep 2016; 6:30385. [PMID: 27461900 PMCID: PMC4961961 DOI: 10.1038/srep30385] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/30/2016] [Indexed: 01/20/2023] Open
Abstract
Using dedicated contrast agents high-quality X-ray imaging of soft tissue structures with isotropic micrometre resolution has become feasible. This technique is frequently titled as virtual histology as it allows production of slices of tissue without destroying the sample. The use of contrast agents is, however, often an irreversible time-consuming procedure and despite the non-destructive principle of X-ray imaging, the sample is usually no longer usable for other research methods. In this work we present the application of recently developed large-area photon counting detector for high resolution X-ray micro-radiography and micro-tomography of whole ex-vivo ethanol-preserved mouse organs. The photon counting detectors provide dark-current-free quantum-counting operation enabling acquisition of data with virtually unlimited contrast-to-noise ratio (CNR). Thanks to the very high CNR even ethanol-only preserved soft-tissue samples without addition of any contrast agent can be visualized in great detail. As ethanol preservation is one of the standard steps of tissue fixation for histology, the presented method can open a way for widespread use of micro-CT with all its advantages for routine 3D non-destructive soft-tissue visualisation.
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21
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Morales AG, Stempinski ES, Xiao X, Patel A, Panna A, Olivier KN, McShane PJ, Robinson C, George AJ, Donahue DR, Chen P, Wen H. Micro-CT scouting for transmission electron microscopy of human tissue specimens. J Microsc 2016; 263:113-7. [PMID: 26854176 DOI: 10.1111/jmi.12385] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/12/2016] [Indexed: 11/27/2022]
Abstract
Transmission electron microscopy (TEM) provides sub-nanometre-scale details in volumetric samples. Samples such as pathology tissue specimens are often stained with a metal element to enhance contrast, which makes them opaque to optical microscopes. As a result, it can be a lengthy procedure to find the region of interest inside a sample through sectioning. We describe micro-CT scouting for TEM that allows noninvasive identification of regions of interest within a block sample to guide the sectioning step. In a tissue pathology study, a bench-top micro-CT scanner with 10 μm resolution was used to determine the location of patches of the mucous membrane in osmium-stained human nasal scraping samples. Once the regions of interest were located, the sample block was sectioned to expose that location, followed by ultra-thin sectioning and TEM to inspect the internal structure of the cilia of the membrane epithelial cells with nanometre resolution. This method substantially reduced the time and labour of the search process from typically 20 sections for light microscopy to three sections with no added sample preparation.
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Affiliation(s)
- A G Morales
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - E S Stempinski
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - X Xiao
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, U.S.A
| | - A Patel
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - A Panna
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - K N Olivier
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - P J McShane
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - C Robinson
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - A J George
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - D R Donahue
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - P Chen
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - H Wen
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
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22
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Walton LA, Bradley RS, Withers PJ, Newton VL, Watson REB, Austin C, Sherratt MJ. Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography. Sci Rep 2015; 5:10074. [PMID: 25975937 PMCID: PMC4650804 DOI: 10.1038/srep10074] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/27/2015] [Indexed: 02/08/2023] Open
Abstract
Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons.
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Affiliation(s)
| | | | | | - Victoria L. Newton
- Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Rachel E. B. Watson
- Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Clare Austin
- Institute of Cardiovascular Sciences
- Faculty of Health and Social Care, Edge Hill University, Ormskirk, United Kingdom
| | - Michael J. Sherratt
- Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
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23
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Barrett HE, Mulvihill JJ, Cunnane EM, Walsh MT. Characterising human atherosclerotic carotid plaque tissue composition and morphology using combined spectroscopic and imaging modalities. Biomed Eng Online 2015; 14 Suppl 1:S5. [PMID: 25602176 PMCID: PMC4306117 DOI: 10.1186/1475-925x-14-s1-s5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Calcification is a marked pathological component in carotid artery plaque. Studies have suggested that calcification may induce regions of high stress concentrations therefore increasing the potential for rupture. However, the mechanical behaviour of the plaque under the influence of calcification is not fully understood. A method of accurately characterising the calcification coupled with the associated mechanical plaque properties is needed to better understand the impact of calcification on the mechanical behaviour of the plaque during minimally invasive treatments. This study proposes a comparison of biochemical and structural characterisation methods of the calcification in carotid plaque specimens to identify plaque mechanical behaviour. Biochemical analysis, by Fourier Transform Infrared (FTIR) spectroscopy, was used to identify the key components, including calcification, in each plaque sample. However, FTIR has a finite penetration depth which may limit the accuracy of the calcification measurement. Therefore, this FTIR analysis was coupled with the identification of the calcification inclusions located internally in the plaque specimen using micro x-ray computed tomography (μX-CT) which measures the calcification volume fraction (CVF) to total tissue content. The tissue characterisation processes were then applied to the mechanical material plaque properties acquired from experimental circumferential loading of human carotid plaque specimen for comparison of the methods. FTIR characterised the degree of plaque progression by identifying the functional groups associated with lipid, collagen and calcification in each specimen. This identified a negative relationship between stiffness and 'lipid to collagen' and 'calcification to collagen' ratios. However, μX-CT results suggest that CVF measurements relate to overall mechanical stiffness, while peak circumferential strength values may be dependent on specific calcification geometries. This study demonstrates the need to fully characterise the calcification structure of the plaque tissue and that a combination of FTIR and μX-CT provides the necessary information to fully understand the mechanical behaviour of the plaque tissue.
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24
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Heinonen SE, Genové G, Bengtsson E, Hübschle T, Åkesson L, Hiss K, Benardeau A, Ylä-Herttuala S, Jönsson-Rylander AC, Gomez MF. Animal models of diabetic macrovascular complications: key players in the development of new therapeutic approaches. J Diabetes Res 2015; 2015:404085. [PMID: 25785279 PMCID: PMC4345079 DOI: 10.1155/2015/404085] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/26/2015] [Indexed: 12/19/2022] Open
Abstract
Diabetes mellitus is a lifelong, incapacitating metabolic disease associated with chronic macrovascular complications (coronary heart disease, stroke, and peripheral vascular disease) and microvascular disorders leading to damage of the kidneys (nephropathy) and eyes (retinopathy). Based on the current trends, the rising prevalence of diabetes worldwide will lead to increased cardiovascular morbidity and mortality. Therefore, novel means to prevent and treat these complications are needed. Under the auspices of the IMI (Innovative Medicines Initiative), the SUMMIT (SUrrogate markers for Micro- and Macrovascular hard end points for Innovative diabetes Tools) consortium is working on the development of novel animal models that better replicate vascular complications of diabetes and on the characterization of the available models. In the past years, with the high level of genomic information available and more advanced molecular tools, a very large number of models has been created. Selecting the right model for a specific study is not a trivial task and will have an impact on the study results and their interpretation. This review gathers information on the available experimental animal models of diabetic macrovascular complications and evaluates their pros and cons for research purposes as well as for drug development.
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Affiliation(s)
- Suvi E. Heinonen
- Bioscience, Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development, AstraZeneca R&D, 43183 Mölndal, Sweden
- *Suvi E. Heinonen:
| | - Guillem Genové
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Eva Bengtsson
- Department of Clinical Sciences, Lund University Diabetes Centre (LUDC), Lund University, 20502 Malmö, Sweden
| | - Thomas Hübschle
- R&D Diabetes Division, Translational Medicine, Sanofi-Aventis, 65926 Frankfurt am Main, Germany
| | - Lina Åkesson
- Department of Clinical Sciences, Lund University Diabetes Centre (LUDC), Lund University, 20502 Malmö, Sweden
| | - Katrin Hiss
- R&D Diabetes Division, Translational Medicine, Sanofi-Aventis, 65926 Frankfurt am Main, Germany
| | - Agnes Benardeau
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210 Kuopio, Finland
| | - Seppo Ylä-Herttuala
- Pharmaceutical Division, pRED, CV and Metabolic Disease, Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Ann-Cathrine Jönsson-Rylander
- Bioscience, Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development, AstraZeneca R&D, 43183 Mölndal, Sweden
| | - Maria F. Gomez
- Department of Clinical Sciences, Lund University Diabetes Centre (LUDC), Lund University, 20502 Malmö, Sweden
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25
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Styner M, Thompson WR, Galior K, Uzer G, Wu X, Kadari S, Case N, Xie Z, Sen B, Romaine A, Pagnotti GM, Rubin CT, Styner MA, Horowitz MC, Rubin J. Bone marrow fat accumulation accelerated by high fat diet is suppressed by exercise. Bone 2014; 64:39-46. [PMID: 24709686 PMCID: PMC4041820 DOI: 10.1016/j.bone.2014.03.044] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/17/2014] [Accepted: 03/25/2014] [Indexed: 01/14/2023]
Abstract
Marrow adipose tissue (MAT), associated with skeletal fragility and hematologic insufficiency, remains poorly understood and difficult to quantify. We tested the response of MAT to high fat diet (HFD) and exercise using a novel volumetric analysis, and compared it to measures of bone quantity. We hypothesized that HFD would increase MAT and diminish bone quantity, while exercise would slow MAT acquisition and promote bone formation. Eight week-old female C57BL/6 mice were fed a regular (RD) or HFD, and exercise groups were provided voluntary access to running wheels (RD-E, HFD-E). Femoral MAT was assessed by μCT (lipid binder osmium) using a semi-automated approach employing rigid co-alignment, regional bone masks and was normalized for total femoral volume (TV) of the bone compartment. MAT was 2.6-fold higher in HFD relative to RD mice. Exercise suppressed MAT in RD-E mice by more than half compared with RD. Running similarly inhibited MAT acquisition in HFD mice. Exercise significantly increased bone quantity in both diet groups. Thus, HFD caused significant accumulation of MAT; importantly running exercise limited MAT acquisition while promoting bone formation during both diets. That MAT is exquisitely responsive to diet and exercise, and its regulation by exercise appears to be inversely proportional to effects on exercise induced bone formation, is relevant for an aging and sedentary population.
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Affiliation(s)
- Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
| | - William R Thompson
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Kornelia Galior
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Xin Wu
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Sanjay Kadari
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Natasha Case
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andrew Romaine
- Department of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Gabriel M Pagnotti
- Department of Biomedical Engineering, State University of New York, Stony Brook, NY, USA
| | - Clinton T Rubin
- Department of Biomedical Engineering, State University of New York, Stony Brook, NY, USA
| | - Martin A Styner
- Department of Computer Science, University of North Carolina, Chapel Hill, NC, USA; Department of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Mark C Horowitz
- Department of Orthopedics and Rehabilitation, Yale University, New Haven, CT, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
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26
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Holme MN, Schulz G, Deyhle H, Weitkamp T, Beckmann F, Lobrinus JA, Rikhtegar F, Kurtcuoglu V, Zanette I, Saxer T, Müller B. Complementary X-ray tomography techniques for histology-validated 3D imaging of soft and hard tissues using plaque-containing blood vessels as examples. Nat Protoc 2014; 9:1401-15. [PMID: 24853926 DOI: 10.1038/nprot.2014.091] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A key problem in X-ray computed tomography is choosing photon energies for postmortem specimens containing both soft and hard tissues. Increasing X-ray energy reduces image artifacts from highly absorbing hard tissues including plaque, but it simultaneously decreases contrast in soft tissues including the endothelium. Therefore, identifying the lumen within plaque-containing vessels is challenging. Destructive histology, the gold standard for tissue evaluation, reaches submicron resolution in two dimensions, whereas slice thickness limits spatial resolution in the third. We present a protocol to systematically analyze heterogeneous tissues containing weakly and highly absorbing components in the original wet state, postmortem. Taking the example of atherosclerotic human coronary arteries, the successively acquired 3D data of benchtop and synchrotron radiation-based tomography are validated by histology. The entire protocol requires ∼20 working days, enables differentiation between plaque, muscle and fat tissues without using contrast agents and permits blood flow simulations in vessels with plaque-induced constrictions.
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Affiliation(s)
- Margaret N Holme
- Biomaterials Science Center (BMC), University of Basel, University Hospital Basel, Basel, Switzerland
| | - Georg Schulz
- Biomaterials Science Center (BMC), University of Basel, University Hospital Basel, Basel, Switzerland
| | - Hans Deyhle
- Biomaterials Science Center (BMC), University of Basel, University Hospital Basel, Basel, Switzerland
| | | | - Felix Beckmann
- Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
| | | | - Farhad Rikhtegar
- Laboratory of Thermodynamics in Emerging Technologies, ETH Zurich, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Irene Zanette
- 1] European Synchrotron Radiation Facility, Grenoble, France. [2] Physik-Department, Technische Universität München, Garching, Germany
| | - Till Saxer
- University Hospitals Geneva, Geneva, Switzerland
| | - Bert Müller
- Biomaterials Science Center (BMC), University of Basel, University Hospital Basel, Basel, Switzerland
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27
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Dunmore-Buyze PJ, Tate E, Xiang FL, Detombe SA, Nong Z, Pickering JG, Drangova M. Three-dimensional imaging of the mouse heart and vasculature using micro-CT and whole-body perfusion of iodine or phosphotungstic acid. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 9:383-90. [PMID: 24764151 DOI: 10.1002/cmmi.1588] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 12/20/2022]
Abstract
Recent studies have investigated histological staining compounds as micro-computed tomography (micro-CT) contrast agents, delivered by soaking tissue specimens in stain and relying on passive diffusion for agent uptake. This study describes a perfusion approach using iodine or phosphotungstic acid (PTA) stains, delivered to an intact mouse, to capitalize on the microvasculature as a delivery conduit for parenchymal staining and direct contact for staining artery walls. Twelve C57BL/6 mice, arterially perfused with either 25% Lugol's solution or 5% PTA solution were scanned intact and reconstructed with 26 µm isotropic voxels. The animals were fixed and the heart and surrounding vessels were excised, embedded and scanned; isolated heart images were reconstructed with 13 µm isotropic voxels. Myocardial enhancement and artery diameters were measured. Both stains successfully enhanced the myocardium and vessel walls. Interestingly, Lugol's solution provided a significantly higher enhancement of the myocardium than PTA [2502 ± 437 vs 656 ± 178 Hounsfield units (HU); p < 0.0001], delineating myofiber architecture and orientation. There was no significant difference in vessel wall enhancement (Lugol's, 1036 ± 635 HU; PTA, 738 ± 124 HU; p = 0.29), but coronary arteries were more effectively segmented from the PTA-stained hearts, enabling segmented imaging of fifth- order coronary artery branches. The combination of whole mouse perfusion delivery and use of heavy metal-containing stains affords high-resolution imaging of the mouse heart and vasculature by micro-CT. The differential imaging patterns of Lugol's- and PTA-stained tissues reveals new opportunities for micro-analyses of cardiac and vascular tissues.
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Affiliation(s)
- P Joy Dunmore-Buyze
- Robarts Research Institute, The University of Western Ontario, London, ON, Canada
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28
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Towards mechanical characterization of intact endarterectomy samples of carotid arteries during inflation using Echo-CT. J Biomech 2014; 47:805-14. [DOI: 10.1016/j.jbiomech.2014.01.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 11/18/2022]
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29
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Yang L, Chu X, Wang F, Li Y, Zhang L. Investigation of selective and effective recovery of noble metal osmium by adsorption onto nano-Al2O3 particles. NEW J CHEM 2014. [DOI: 10.1039/c3nj01582c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Tahara R, Larsson HCE. Quantitative analysis of microscopic X-ray computed tomography imaging: Japanese quail embryonic soft tissues with iodine staining. J Anat 2013; 223:297-310. [PMID: 23869493 PMCID: PMC3972050 DOI: 10.1111/joa.12081] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 12/27/2022] Open
Abstract
Rapid three-dimensional imaging of embryos to better understand the complex process of morphogenesis has been challenging. Recently introduced iodine staining protocols (I2 KI and alcoholic iodine stains) combined with microscopic X-ray computed tomography allows visualization of soft tissues in diverse small organisms and tissue specimens. I2 KI protocols have been developed specifically for small animals, with a limited number of quantitative studies of soft tissue contrasts. To take full advantage of the low X-ray attenuation of ethanol and retain bound iodine while dehydrating the specimen in ethanol, we developed an ethanol I2 KI protocol. We present comparative microscopic X-ray computed tomography analyses of ethanol I2 KI and I2 KI staining protocols to assess the performance of this new protocol to visualize soft tissue anatomy in late stage Japanese quail embryos using quantitative measurements of soft tissue contrasts and sample shrinkage. Both protocols had only 5% shrinkage compared with the original harvested specimen, supporting the use of whole mounts to minimize tissue shrinkage effects. Discrimination within and among the selected organs with each staining protocol and microscopic X-ray computed tomography imaging were comparable to those of a gray scale histological section. Tissue discrimination was assessed using calibrated computed tomography values and a new discrimination index to quantify the degree of computed tomography value overlaps between selected soft tissue regions. Tissue contrasts were dependent on the depth of the tissue within the embryos before the embryos were saturated with each stain solution, and optimal stain saturations for the entire embryo were achieved at 14 and 28 days staining for I2 KI and ethanol I2 KI, respectively. Ethanol I2 KI provided superior soft tissue contrasts by reducing overstaining of fluid-filled spaces and differentially modulating staining of some tissues, such as bronchial and esophageal walls and spinal cord. Delineating the selected soft tissues using optimal threshold ranges derived from the quantitative analyses of the contrast enhancement in optimally stained embryos is possible. The protocols presented here are expected to be applicable to other organisms with modifications to staining time and contribute toward rapid and more efficient segmentation of soft tissues for three-dimensional visualization.
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Affiliation(s)
- Rui Tahara
- Redpath Museum, McGill University, Montreal, QC, Canada.
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31
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Schlett CL, Ferencik M, Celeng C, Maurovich-Horvat P, Scheffel H, Stolzmann P, Do S, Kauczor HU, Alkadhi H, Bamberg F, Hoffmann U. How to assess non-calcified plaque in CT angiography: delineation methods affect diagnostic accuracy of low-attenuation plaque by CT for lipid-core plaque in histology. Eur Heart J Cardiovasc Imaging 2013; 14:1099-105. [PMID: 23671211 DOI: 10.1093/ehjci/jet030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS To compare the accuracy of two plaque delineation methods for coronary computed tomographic angiography (CTA) to identify lipid-core plaque (LCP) using histology as the reference standard. METHODS AND RESULTS Five ex vivo hearts were analysed by CTA and histology. LCP was defined by histology as fibroatheroma with core diameter/circumference >200 μm/>60° and cap thickness <450 μm. In CTA, plaque was manually delineated either as the difference between the inner and outer vessel walls (Method A) or as a direct tracing of plaque (Method B). Low-attenuation plaque was defined as an area with <90 Hounsfield units. Of 446 co-registered cross-sections, 55 (12%) contained LCP. In CTA, low-attenuation plaque area was larger as assessed with Method A compared with Method B (difference: 120 ± 60%). Although low-attenuation plaque was associated with the presence of LCP, the delineation Method B yielded higher diagnostic accuracy than Method A [area under the curve (AUC): 0.831 vs. 0.780, respectively, P = 0.005]. After excluding 'normal' cross-sections by CTA (n = 117), AUC for detecting LCP became similar between both methods (0.767 vs. 0.729, P = 0.07, respectively). CONCLUSION Low-attenuation plaque in CTA is a diagnostic tool for LCP but prone to error if plaque is defined as the area between the inner and outer vessel walls and normal cross-sections are included in the assessment.
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Affiliation(s)
- Christopher L Schlett
- Cardiac MR PET CT Program, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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