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Banerjee A, Indoliya A, Poddar R. Edible oil based optical clearing for optical coherence tomography angiography imaging. Microvasc Res 2024; 154:104671. [PMID: 38460712 DOI: 10.1016/j.mvr.2024.104671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/19/2024] [Accepted: 03/04/2024] [Indexed: 03/11/2024]
Abstract
In optical imaging, optical clearing agents are commonly used to enhance the structural details of a sample. The current study investigates how to use it to improve the data obtained by an optical coherence tomography angiography system. A natural edible oil with no chemical base has been used for optical clearing. In-vivo testing on mice and humans yielded excellent optical clearing. Using computational techniques, the improvement in angiography signal caused by the optical clearing agent is investigated qualitatively and quantitatively. Compared to the control group, applying the edible oil-based optical clearing agent demonstrated improved vessel percentage and refined vascular signal intensity along depth.
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Affiliation(s)
- Abhishek Banerjee
- Biophotonics Lab, Department of Bioengineering, Birla Institute of Technology-Mesra, Ranchi, JH 835215, India
| | - Abhishek Indoliya
- Biophotonics Lab, Department of Bioengineering, Birla Institute of Technology-Mesra, Ranchi, JH 835215, India
| | - Raju Poddar
- Biophotonics Lab, Department of Bioengineering, Birla Institute of Technology-Mesra, Ranchi, JH 835215, India.
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2
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Lee YH, Huang CY, Hsieh YH, Yang CH, Hung YL, Chen YA, Lin YC, Lin CH, Lee JH, Wang MY, Kuo WH, Lin YY, Lu YS. A novel computer-assisted tool for 3D imaging of programmed death-ligand 1 expression in immunofluorescence-stained and optically cleared breast cancer specimens. BMC Cancer 2024; 24:121. [PMID: 38267903 PMCID: PMC10807239 DOI: 10.1186/s12885-023-11748-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 12/12/2023] [Indexed: 01/26/2024] Open
Abstract
BACKGROUND Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) are the two most common immune checkpoints targeted in triple-negative breast cancer (BC). Refining patient selection for immunotherapy is non-trivial and finding an appropriate digital pathology framework for spatial analysis of theranostic biomarkers for PD-1/PD-L1 inhibitors remains an unmet clinical need. METHODS We describe a novel computer-assisted tool for three-dimensional (3D) imaging of PD-L1 expression in immunofluorescence-stained and optically cleared BC specimens (n = 20). The proposed 3D framework appeared to be feasible and showed a high overall agreement with traditional, clinical-grade two-dimensional (2D) staining techniques. Additionally, the results obtained for automated immune cell detection and analysis of PD-L1 expression were satisfactory. RESULTS The spatial distribution of PD-L1 expression was heterogeneous across various BC tissue layers in the 3D space. Notably, there were six cases (30%) wherein PD-L1 expression levels along different layers crossed the 1% threshold for admitting patients to PD-1/PD-L1 inhibitors. The average PD-L1 expression in 3D space was different from that of traditional immunohistochemistry (IHC) in eight cases (40%). Pending further standardization and optimization, we expect that our technology will become a valuable addition for assessing PD-L1 expression in patients with BC. CONCLUSION Via a single round of immunofluorescence imaging, our approach may provide a considerable improvement in patient stratification for cancer immunotherapy as compared with standard techniques.
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Affiliation(s)
- Yi-Hsuan Lee
- Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chung-Yen Huang
- Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan
| | | | | | | | | | | | - Ching-Hung Lin
- Department of Medical Oncology, Cancer Center Branch, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jih-Hsiang Lee
- Department of Oncology, National Taiwan University Hospital, Hsin-Chu Branch, Hsinchu, Taiwan
| | - Ming-Yang Wang
- Department of Surgical Oncology, Cancer Center Branch, National Taiwan University Hospital, Taipei, Taiwan
| | - Wen-Hung Kuo
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | | | - Yen-Shen Lu
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.
- Department of Oncology, National Taiwan University Hospital, No.7, Chung Shan S. Rd., Zhongzheng Dist, Taipei, 100225, Taiwan.
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3
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Ascheid D, Baumann M, Funke C, Volz J, Pinnecker J, Friedrich M, Höhn M, Nandigama R, Ergün S, Nieswandt B, Heinze KG, Henke E. Image-based modeling of vascular organization to evaluate anti-angiogenic therapy. Biol Direct 2023; 18:10. [PMID: 36922848 PMCID: PMC10018970 DOI: 10.1186/s13062-023-00365-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/07/2023] [Indexed: 03/17/2023] Open
Abstract
In tumor therapy anti-angiogenic approaches have the potential to increase the efficacy of a wide variety of subsequently or co-administered agents, possibly by improving or normalizing the defective tumor vasculature. Successful implementation of the concept of vascular normalization under anti-angiogenic therapy, however, mandates a detailed understanding of key characteristics and a respective scoring metric that defines an improved vasculature and thus a successful attempt. Here, we show that beyond commonly used parameters such as vessel patency and maturation, anti-angiogenic approaches largely benefit if the complex vascular network with its vessel interconnections is both qualitatively and quantitatively assessed. To gain such deeper insight the organization of vascular networks, we introduce a multi-parametric evaluation of high-resolution angiographic images based on light-sheet fluorescence microscopy images of tumors. We first could pinpoint key correlations between vessel length, straightness and diameter to describe the regular, functional and organized structure observed under physiological conditions. We found that vascular networks from experimental tumors diverted from those in healthy organs, demonstrating the dysfunctionality of the tumor vasculature not only on the level of the individual vessel but also in terms of inadequate organization into larger structures. These parameters proofed effective in scoring the degree of disorganization in different tumor entities, and more importantly in grading a potential reversal under treatment with therapeutic agents. The presented vascular network analysis will support vascular normalization assessment and future optimization of anti-angiogenic therapy.
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Affiliation(s)
- David Ascheid
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Magdalena Baumann
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Caroline Funke
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Julia Volz
- Institute of Experimental Biomedicine I, Universitätsklinikum Würzburg, Würzburg, Germany
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany
| | - Jürgen Pinnecker
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany
| | - Mike Friedrich
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany
| | - Marie Höhn
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Rajender Nandigama
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine I, Universitätsklinikum Würzburg, Würzburg, Germany
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany
| | - Katrin G Heinze
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Universität Würzburg, Josef-Schneider-Straße 2, 97080, Würzburg, Germany.
| | - Erik Henke
- Institute of Anatomy and Cell Biology, Universität Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany.
- Graduate School for Life Sciences, Universität Würzburg, Würzburg, Germany.
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4
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Rakhilin N, Yang B, Spilker ME, Manzuk LK, Montgomery MK, Shin E, Prashad N, Hwang J, Song Y, Loganzo F, Giddabasappa A, Ram S. Volumetric imaging of optically cleared and fluorescently labeled animal tissue (VIOLA) for quantifying the 3D biodistribution of nanoparticles at cellular resolution in tumor tissue. J Control Release 2023; 354:244-259. [PMID: 36596340 DOI: 10.1016/j.jconrel.2022.12.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/17/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023]
Abstract
Nanoparticle (NP) technology holds significant promise to mediate targeted drug delivery to specific organs in the body. Understanding the 3D biodistribution of NPs in heterogeneous environments such as the tumor tissue can provide crucial information on efficacy, safety and potential clinical outcomes. Here we present a novel end-to-end workflow, VIOLA, which makes use of tissue clearing methodology in conjunction with high resolution imaging and advanced 3D image processing to quantify the spatiotemporal 3D biodistribution of fluorescently labeled ACCURIN® NPs. Specifically, we investigate the spatiotemporal biodistribution of NPs in three different murine tumor models (CT26, EMT6, and KPC-GEM) of increasing complexity and translational relevance. We have developed new endpoints to characterize NP biodistribution at multiple length scales. Our observations reveal that the macroscale NP biodistribution is spatially heterogeneous and exhibits a gradient with relatively high accumulation at the tumor periphery that progressively decreases towards the tumor core in all the tumor models. Microscale analysis revealed that NP extravasation from blood vessels increases in a time dependent manner and plateaus at 72 h post injection. Volumetric analysis and pharmacokinetic modeling of NP biodistribution in the vicinity of the blood vessels revealed that the local NP density exhibits a distance dependent spatiotemporal biodistribution which provide insights into the dynamics of NP extravasation in the tumor tissue. Our data represents a comprehensive analysis of NP biodistribution at multiple length scales in different tumor models providing unique insights into their spatiotemporal dynamics. Specifically, our results show that NPs exhibit a dynamic equilibrium with macroscale heterogeneity combined with microscale homogeneity.
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Affiliation(s)
| | - Bing Yang
- Comparative Medicine, Pfizer Inc., United States
| | - Mary E Spilker
- Medicine Design - Translational Modeling and Simulation, Pfizer Inc., United States
| | | | | | - Eyoung Shin
- Oncology Research Unit, Pfizer Inc., United States
| | | | | | - Youngho Song
- Oncology Research Unit, Pfizer Inc., United States
| | | | | | - Sripad Ram
- Drug Safety R&D, Pfizer Inc., United States.
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5
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Unnersjö-Jess D. Quantitative Imaging of Podocyte Foot Processes in the Kidney Using Confocal and STED Microscopy. Methods Mol Biol 2023; 2664:185-199. [PMID: 37423991 DOI: 10.1007/978-1-0716-3179-9_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Morphological alterations to the kidney filter, particularly to podocyte foot processes, are seen in most types of glomerular diseases. Due to the nanoscale dimensions of the filter, visualization of such alterations has historically relied on electron microscopy. However, with recent technical development, it is now possible to also visualize podocyte foot processes, as well as other parts of the kidney filtration barrier, with light microscopy. With developments both in sample preparation, imaging, and image analysis, these new tools are becoming increasingly applied in kidney research, due to their demonstrated quantitative potential. We here present an overview of these protocols that can be applied to samples that have been fixed and stored using most standard procedures used today (i.e., PFA fixed, fresh frozen, formalin-fixed and paraffin-embedded (FFPE)). We additionally introduce tools for quantitative image analysis of foot process morphology and foot process effacement.
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Affiliation(s)
- David Unnersjö-Jess
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- MedTechLabs, Karolinska University Hospital, Solna, Sweden.
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6
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Federspiel JM, Lux C, Burkhard K, Kettner M, Verhoff MA, Tschernig T, Ramsthaler F. Retrograde dye perfusion of the proximal aorta - A postmortem technical study. Heliyon 2022; 8:e12475. [PMID: 36636207 PMCID: PMC9830167 DOI: 10.1016/j.heliyon.2022.e12475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 10/24/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Introduction Multiple cardiovascular conditions can lead to unexpected fatality, which is defined as sudden cardiac death. One of these potentially underlying conditions is aortic regurgitation, which can be caused by discrete changes of the geometry of the proximal aorta. To analyze aortic valve competency and furthermore to elucidate underlying pathological alterations of the coronary arteries and the vasa vasorum a perfusion method to simulate a diastolic state was designed. Material and methods A postmortem approach with retrograde perfusion of the ascending aorta with methylene blue was applied to three bodies. The procedure comprised cannulation of the brachiocephalic trunk, clamping of the aortic arch between brachiocephalic trunk and left carotid artery, infusion of 250 ml of methylene blue, and optical clearing of the superficial tissue layers after perfusion. Organs were examined directly following perfusion and after optical clearing. Results Assessment and visualization of aortic valve competency and the vasa vasorum were possible in all three instances. Visualization of the coronary perfusion was impaired by postmortem thrombus formation. Optical clearing did not provide additional information. Discussion The method presented here is a time- and cost-efficient way of visualizing aortic valve competency and the vasa vasorum. The visualization of the vasa vasorum highlights the potential of this method in basic research on diseases of the great arteries and coronaries. However, for a time-efficient functional analysis of the coronaries, other methods must be applied.
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Affiliation(s)
- Jan M. Federspiel
- Institute for Legal Medicine, Saarland University, Campus Homburg, Kirrberger Straße, Building 49.1, 66421, Homburg/Saar, Germany,Corresponding author.
| | - Constantin Lux
- Institute for Legal Medicine, University Hospital Frankfurt, Goethe University, Kennedyallee 104, 60596 Frankfurt, Germany
| | - Katrin Burkhard
- Institute for Legal Medicine, University Hospital Frankfurt, Goethe University, Kennedyallee 104, 60596 Frankfurt, Germany
| | - Mattias Kettner
- Institute for Legal Medicine, University Hospital Frankfurt, Goethe University, Kennedyallee 104, 60596 Frankfurt, Germany
| | - Marcel A. Verhoff
- Institute for Legal Medicine, University Hospital Frankfurt, Goethe University, Kennedyallee 104, 60596 Frankfurt, Germany
| | - Thomas Tschernig
- Institute for Anatomy, Saarland University, Medical Campus, Kirrberger Straße, Building 61, Homburg/Saar, Germany
| | - Frank Ramsthaler
- Institute for Legal Medicine, Saarland University, Campus Homburg, Kirrberger Straße, Building 49.1, 66421, Homburg/Saar, Germany
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Abstract
The rodent pancreas is the prevalent model system for preclinical diabetes research. However, due to the compound endocrine-exocrine organization of the gland, with the endocrine islets of Langerhans scattered by the thousands throughout the much greater exocrine parenchyma, stereological assessments of endocrine cell mass, commonly insulin-producing ß-cells, are exceedingly challenging. In recent years, optical mesoscopic imaging techniques such as optical projection tomography (OPT) and light sheet fluorescence microscopy (LSFM) have seen dramatic developments, enabling 3D visualization of fluorescently labeled cells in mm- to cm-sized tissues with μm resolution. Here we present a protocol for 3D visualization and "absolute" quantitative assessments of, for example, islet mass throughout the volume of rodent pancreata with maintained spatial context.
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8
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Jiang W, Chen L, Wang J, Shao X, Jiang M, Chen Z, Wang J, Huang Y, Fei P. Open-top light-sheet imaging of CLEAR emulsion for high-throughput loss-free analysis of massive fluorescent droplets. Biomed Phys Eng Express 2022; 8. [PMID: 35767965 DOI: 10.1088/2057-1976/ac7d0f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/29/2022] [Indexed: 11/12/2022]
Abstract
Digital droplet PCR (ddPCR) is classified as the third-generation PCR technology that enables absolute quantitative detection of nucleic acid molecules and has become an increasingly powerful tool for clinic diagnosis. We previously established a CLEAR-dPCR technique based on the combination of CLEAR droplets generated by micro-centrifuge-based microtubule arrays (MiCA) andinsitu3D readout by light-sheet fluorescence imaging. This CLEAR-dPCR technique attains very high readout speed and dynamic range. Meanwhile, it is free from sample loss and contamination, showing its advantages over commercial d-PCR technologies. However, a conventional orthogonal light-sheet imaging setup in CLEAR d-PCR cannot image multiple centrifuge tubes, thereby limiting its widespread application to large-scale, high-speed dd-PCR assays. Herein, we propose an in-parallel 3D dd-PCR readout technique based on an open-top light-sheet microscopy setup. This approach can continuously scan multiple centrifuge tubes which contain CLEAR emulsions with highly diverse concentrations, and thus further boost the scale and throughput of our 3D dd-PCR technique.
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Affiliation(s)
- Wen Jiang
- School of Optical and Electronic Information , Huazhong University of Science and Technology, E417, Wuhan, Hubei, 430074, CHINA
| | - Longbiao Chen
- School of Optical and Electronic Information , Huazhong University of Science and Technology, E417, Wuhan, Hubei, 430074, CHINA
| | - Jie Wang
- Huazhong University of Science and Technology, E417, School of Optical and Electronic Information, Wuhan, Hubei, 430074, CHINA
| | - Xinyang Shao
- Peking-Tsinghua Center for Life Sciences, Peking University, Peking-Tsinghua Center for Life Sciences, Beijing, Beijing, 100871, CHINA
| | - Mengcheng Jiang
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Biomedical Pioneering Innovation Center (BIOPIC), Beijing, Beijing, 100871, CHINA
| | - Zitian Chen
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Biomedical Pioneering Innovation Center (BIOPIC), Beijing, Beijing, 100871, CHINA
| | - Jianbin Wang
- School of Life Sciences, Tsinghua University, School of Life Sciences, Beijing, Beijing, 100084, CHINA
| | - Yanyi Huang
- College of Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, College of Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Beijing, 100871, CHINA
| | - Peng Fei
- School of Optical and Electronic Information, Huazhong University of Science and Technology, E417, Wuhan, 430074, CHINA
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Abstract
The soft marrow tissues, which are found disseminated throughout bone cavities, are prime sites for hematopoietic cell production, development, and control of immune responses, and regulation of skeletal metabolism. These essential functions are executed through the concerted and finely tuned interaction of a large variety of cell types of hematopoietic and nonhematopoietic origin, through yet largely unknown sophisticated molecular mechanisms. A fundamental insight of the biological underpinnings of organ function can be gained from the microscopic study of the bone marrow (BM), its complex structural organization and the existence of cell-specific spatial associations. Albeit the application of advanced imaging techniques to the analysis of BM has historically proved challenging, recent technological developments now enable the interrogation of organ-wide regions of marrow tissues in three dimensions at high resolution. Here, we provide a detailed experimental protocol for the generation of thick slices of BM from murine femoral cavities, the immunostaining of cellular and structural components within these samples, and their optical clearing, which enhances the depth at which optical sectioning can be performed with standard confocal microscopes. Collectively, the experimental pipeline here described allows for the rendering of single-cell resolution, multidimensional reconstructions of vast volumes of the complex BM microenvironment.
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Na M, Kim K, Lim HR, Ha CM, Chang S. Rapid immunostaining method for three-dimensional volume imaging of biological tissues by magnetic force-induced focusing of the electric field. Brain Struct Funct 2021; 226:297-309. [PMID: 33175320 DOI: 10.1007/s00429-020-02160-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/15/2020] [Indexed: 12/30/2022]
Abstract
Recent surges in tissue clearing technology have greatly advanced 3-dimensional (3D) volume imaging. Cleared tissues need to be stained with fluorescence probes for imaging but the current staining methods are too laborious and inefficient for thick 3D samples, which impedes the broad application of clearing technology. To overcome these limitations, we developed an advanced staining platform named EFIC in which a magnetic force focuses the electric field by bending it onto the sample. Such that EFIC applies a significantly lower electric field to maintain nanoscale structural integrity while effectively drives staining probes into pre-cleared 3D samples. We found that EFIC achieved a rapid and uniform staining of various proteins and vascular networks of the brain as well as other organs over the entire depth of imaging. EFIC stained tau deposits and the vascular structure in the post-mortem human brain of Alzheimer's disease and intracerebral hemorrhage, respectively, enabling quantitative analysis. The effectiveness of EFIC was further extended by the successful staining of various targets in non-cleared 3D brain samples. Together, EFIC represents a versatile and reliable staining platform for rapidly analyzing 3D molecular signatures and can be applied to sectioning-free 3D histopathology for diagnostic purposes.
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He H, Shen Y, Li B. Rapid skin optical clearing enhancement with salicylic acid for imaging blood vessels in vivo. Photodiagnosis Photodyn Ther 2020; 32:102005. [PMID: 32961325 DOI: 10.1016/j.pdpdt.2020.102005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 08/25/2020] [Accepted: 08/31/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Light penetration in deeper tissue is impeded by the skin scattering properties, which significantly limits the clinical applications of light in medical diagnosis and therapy. To overcome this problem, skin optical clearing methods using different optical clearing agents (OCAs) have been extensively developed to clear the dermis tissue. It is critically important to remove the outmost stratum corneum (SC) before the OCAs were applied for optical clearing, since the SC works as a natural barrier to the OCAs. For this, a controllable approach for the SC disruption through physical or chemical methods is highly required for enhanced skin optical clearing. METHODS Salicylic acid (SA) was combined with OCAs as a rapid skin optical clearing method to create a transparent window within 5 min. The clearing efficacy of this method was demonstrated by using dorsal skin model of mice. In addition, the intensity variations of vessel gray images and diffuse reflectance (DR) spectra were used to quantify the optical clearing efficacy, which were acquired by a low-cost self-built white light imaging system and optical fiber spectrometer, respectively. RESULTS Within a specific action time of the OCAs to the skin tissue, the enhanced images of the deeper blood vessels were obtained through the removal of the SC. It takes 5 min for the skin to turn transparent and 15 min to visualize the microvascular morphology for naked eyes. Furthermore, the intensity of blood vessel gray images was identified to be an evaluation parameter for quantifying the optical clearing efficacy. CONCLUSIONS An efficient and easy-to-handle method for enhanced skin optical clearing was established by combining SA with OCAs, which could boost the clinical applications of light in medical diagnosis and therapy.
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Arms L, Robson AL, Woldu A, Martin A, Palmer W, Flynn J, Hua S. Considerations for using optical clearing techniques for 3D imaging of nanoparticle biodistribution. Int J Pharm 2020; 588:119739. [PMID: 32783979 DOI: 10.1016/j.ijpharm.2020.119739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 02/06/2023]
Abstract
A key consideration in the clinical translation of nanomedicines is determining their in vivo biodistribution in preclinical studies, which is important for predicting and correlating therapeutic efficacy and safety. There are a number of techniques available for analyzing the in vivo biodistribution of nanoparticles, with each having its own advantages and limitations. However, conventional techniques are limited by their inability to image the three-dimensional (3D) association of nanoparticles with cells, vasculature and other biological structures in whole organs at a subcellular level. Recently, optical clearing techniques have been used to evaluate the biodistribution of nanoparticles by 3D organ imaging. Optical clearing is a procedure that is increasingly being used to improve the imaging of biological tissues, whereby light scattering substances are removed to better match the refractive indices of different tissue layers. The use of optical clearing techniques has the potential to transform the way we evaluate the biodistribution of new and existing nanomedicines, as it allows the visualization of the interaction of nanoparticles with the biological environment in intact tissues. This review will compare the main optical clearing techniques and will address the considerations for the use of these techniques to evaluate nanoparticle biodistribution.
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Affiliation(s)
- Lauren Arms
- Therapeutic Targeting Research Group, University of Newcastle, Callaghan, NSW, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
| | - Annie-Louise Robson
- Therapeutic Targeting Research Group, University of Newcastle, Callaghan, NSW, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
| | - Ameha Woldu
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
| | - Antony Martin
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - William Palmer
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Jamie Flynn
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Susan Hua
- Therapeutic Targeting Research Group, University of Newcastle, Callaghan, NSW, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
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13
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Hirashima T. Mechanical Tissue Compression and Whole-mount Imaging at Single CellResolution for Developing Murine Epididymal Tubules. Bio Protoc 2020; 10:e3694. [PMID: 33659362 DOI: 10.21769/bioprotoc.3694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 11/02/2022] Open
Abstract
Cells inside the body are subjected to various mechanical stress, such as stretch or compression provided by surrounding cells, shear stresses by blood or lymph flows, and normal stresses by luminal liquids. Force loading to the biological tissues is a fundamental method to better understand cellular responses to such mechanical stimuli. There have been many studies on compression or stretch experiments that target culture cells attached to a flexible extensible material including polydimethylsiloxane (PDMS); however, the know-how of those targeting to tissues is still incomplete. Here we present the protocol for mechanical tissue compression and image-based analysis by focusing on developing murine epididymis as an example. We show a series of steps including tissue dissection from murine embryos, hydrogel-based compression method using a manual device, and non-destructive volumetric tissue imaging. This protocol is useful for quantifying and exploring the biological mechanoresponse system at tissue level.
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Affiliation(s)
- Tsuyoshi Hirashima
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Japan Science and Technology Agency, PRESTO, Sakyo-ku, Kyoto, Japan
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14
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Abstract
Optical clearing combined with deep imaging of large biological specimen allows organ-wide visualization of cells in three dimensions (3D) to explore regenerative processes in a spatial context. Here, we investigate the dynamics of airway regeneration following toxin-mediated epithelial injury in cleared whole lung preparations by light sheet microscopy. We use a recently developed knock-in mouse strain labeling bronchiolar Club cells (Scgb1a1-mCherry) to define an optimal clearing procedure that efficiently preserves genetically encoded fluorophores. Dehydration in pH-adjusted tert-butanol followed by clearing in ethyl cinnamate maintained maximum mCherry fluorescence while preventing unfavorable background fluorescence. We apply this technique to depict the course of bronchiolar epithelial renewal from an acute injury phase to early and late recovery stages. 3D reconstructions of whole lungs demonstrate near-complete loss of secretory Club cells throughout the entire respiratory tract 3 days post naphthalene (dpn). Multiple foci of regenerating Club cells emerge at 7 dpn, predominantly at airway bifurcations and in distal terminal bronchioles—anatomical regions assumed to harbor distinct stem/progenitor cells subsets. At 21 dpn, clusters of newly formed Club cells have largely expanded, although the bronchiolar epithelial lining continues to regenerate. This study identifies regional stem cell niches as starting points for epithelial recovery, underscores the enormous regenerative capacity of the respiratory epithelium and demonstrates the power of whole lung 3D imaging for evaluating the extent of pulmonary damage and subsequent repair processes.
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Husna N, Gascoigne NRJ, Tey HL, Ng LG, Tan Y. Reprint of "Multi-modal image cytometry approach - From dynamic to whole organ imaging". Cell Immunol 2020; 350:104086. [PMID: 32169249 DOI: 10.1016/j.cellimm.2020.104086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 12/13/2022]
Abstract
Optical imaging is a valuable tool to visualise biological processes in the context of the tissue. Each imaging modality provides the biologist with different types of information - cell dynamics and migration over time can be tracked with time-lapse imaging (e.g. intra-vital imaging); an overview of whole tissues can be acquired using optical clearing in conjunction with light sheet microscopy; finer details such as cellular morphology and fine nerve tortuosity can be imaged at higher resolution using the confocal microscope. Multi-modal imaging combined with image cytometry - a form of quantitative analysis of image datasets - provides an objective basis for comparing between sample groups. Here, we provide an overview of technical aspects to look out for in an image cytometry workflow, and discuss issues related to sample preparation, image post-processing and analysis for intra-vital and whole organ imaging.
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Affiliation(s)
- Nazihah Husna
- Singapore Immunology Network (SIgN), A*STAR (Agency for Science, Technology and Research), Biopolis, 8A Biomedical Grove, Singapore 138648, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Hong Liang Tey
- National Skin Centre, 1 Mandalay Road, Singapore 308205, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, Singapore 117597, Singapore
| | - Lai Guan Ng
- Singapore Immunology Network (SIgN), A*STAR (Agency for Science, Technology and Research), Biopolis, 8A Biomedical Grove, Singapore 138648, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore.
| | - Yingrou Tan
- Singapore Immunology Network (SIgN), A*STAR (Agency for Science, Technology and Research), Biopolis, 8A Biomedical Grove, Singapore 138648, Singapore; National Skin Centre, 1 Mandalay Road, Singapore 308205, Singapore.
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16
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Gorelashvili MG, Heinze KG, Stegner D. Optical Clearing of Murine Bones to Study Megakaryocytes in Intact Bone Marrow Using Light-Sheet Fluorescence Microscopy. Methods Mol Biol 2018; 1812:233-253. [PMID: 30171582 DOI: 10.1007/978-1-4939-8585-2_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In mammals, the differentiation and maturation of megakaryocytes (MKs) occurs in the bone marrow (BM). The three-dimensional environment influences megakaryopoiesis and platelet release. Thus, imaging MKs within the intact BM is important to understand megakaryopoiesis. Here, we present an optical clearing protocol for intact bones and the subsequent microscopic analysis including image processing to quantitatively assess MK size and distribution. This technique overcomes the limitations of classical sectioning methods as the entire bone can be imaged.
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Affiliation(s)
| | - Katrin G Heinze
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - David Stegner
- Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany.
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Zhang Y, Liu H, Tang J, Li Z, Zhou X, Zhang R, Chen L, Mao Y, Li C. Noninvasively Imaging Subcutaneous Tumor Xenograft by a Handheld Raman Detector, with the Assistance of an Optical Clearing Agent. ACS Appl Mater Interfaces 2017; 9:17769-17776. [PMID: 28474520 DOI: 10.1021/acsami.7b04205] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A handheld Raman detector with operational convenience, high portability, and rapid acquisition rate has been applied in clinics for diagnostic purposes. However, the inherent weakness of Raman scattering and strong scattering of the turbid tissue restricts its utilization to superficial locations. To extend the applications of a handheld Raman detector to deep tissues, a gold nanostar-based surface-enhanced Raman scattering (SERS) nanoprobe with robust colloidal stability, a fingerprint-like spectrum, and extremely high sensitivity (5.0 fM) was developed. With the assistance of FPT, a multicomponent optical clearing agent (OCA) efficiently suppressing light scattering from the turbid dermal tissues, the handheld Raman detector noninvasively visualized the subcutaneous tumor xenograft with a high target-to-background ratio after intravenous injection of the gold nanostar-based SERS nanoprobe. To the best of our knowledge, this work is the first example to introduce the optical clearing technique in assisting SERS imaging in vivo. The combination of optical clearing technology and SERS is a promising strategy for the extension of the clinical applications of the handheld Raman detector from superficial tissues to subcutaneous or even deeper lesions that are usually "concealed" by the turbid dermal tissue.
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Affiliation(s)
- Yunfei Zhang
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University , Shanghai 201203, China
| | - Haoran Liu
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University , Shanghai 201203, China
| | - Jiali Tang
- Department of Pharmaceutical Engineering, School of Engineering, China Pharmaceutical University , Nanjing 210009, China
| | - Zhuoyun Li
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University , Shanghai 201203, China
| | - Xingyu Zhou
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University , Shanghai 201203, China
| | - Ren Zhang
- Center of Analysis and Measurement, Fudan University , Shanghai 200433, China
| | - Liang Chen
- Department of Neurosurgery, Huashan Hospital, Fudan University , 12 Wulumuqi Middle Road, Shanghai 200040, China
| | - Ying Mao
- Department of Neurosurgery, Huashan Hospital, Fudan University , 12 Wulumuqi Middle Road, Shanghai 200040, China
| | - Cong Li
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University , Shanghai 201203, China
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18
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Richardson L, Vargas G, Brown T, Ochoa L, Trivedi J, Kacerovský M, Lappas M, Menon R. Redefining 3Dimensional placental membrane microarchitecture using multiphoton microscopy and optical clearing. Placenta 2017; 53:66-75. [PMID: 28487023 DOI: 10.1016/j.placenta.2017.03.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/22/2017] [Accepted: 03/29/2017] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Remodeling of human placental membranes (amniochorionic or fetalmembrane) throughout gestation, a necessity to accommodate increasing uterine volume, involves continuous alterations (replacement of cells and remodeling of extracellular matrix). Methodologic limitations have obscured microscopic determination of cellular and layer-level alterations. This study used a combination of advanced imaging by multiphoton autofluorescence microscopy (MPAM) and second harmonic generation (SHG) microscopy along with tissue optical clearing to characterize the 3Dimensional multilayer organization of placental membranes. METHODS Placental membranes biopsies (6 mm) collected from term, not-in-labor cesarean deliveries (n = 7) were fixed in 10% formalin (native) or treated with 2,2'-thiodiethanol to render them transparent for deeper imaging. Native and cleared tissues were imaged using MPAM (cellular autofluorescence) and SHG (fibrillar collagen). Depth z-stacks captured the amnion epithelium, underlying matrix layers, and in the cleared biopsies, the decidua layer. RESULTS MPAM and SHG revealed fetal membrane epithelial topography and collagen organization in multiple matrix layers. Term amnion layers showed epithelial shedding and gaps. Optical clearing provided full-depth imaging with improved visualization of collagen structure, mesenchymal cells in extracellular matrix layers, and decidua morphology. Layer thicknesses measured by imaging corroborated with histology. Mosaic tiling of MPAM/SHG image stacks allowed large area visualization of entire biopsies. CONCLUSION MPAM-SHG microscopy allowed for study of this multi-layered tissue and revealed shedding, gap formation, and other structural changes. This approach could be used to study structural changes associated with membranes as well as other uterine tissues to better understand events in normal and abnormal parturition.
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Affiliation(s)
- Lauren Richardson
- Department of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine & Perinatal Research, Galveston, TX, USA
| | - Gracie Vargas
- Department of Neuroscience & Cell Biology, Center for Biomedical Engineering, The University of Texas Medical Branch at Galveston, Galveston, TX, USA.
| | - Tyra Brown
- Department of Neuroscience & Cell Biology, Center for Biomedical Engineering, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Lorenzo Ochoa
- Department of Neuroscience & Cell Biology, Center for Biomedical Engineering, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Jayshil Trivedi
- Department of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine & Perinatal Research, Galveston, TX, USA
| | - Marian Kacerovský
- Department of Obstetrics & Gynecology, Charles University in Prague, Faculty of Medicine Hradec Kralove, University Hospital Hradec Kralove, Hradec Kralove, Czechia Republic
| | - Martha Lappas
- Department of Obstetrics & Gynecology, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Melbourne, Australia
| | - Ramkumar Menon
- Department of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine & Perinatal Research, Galveston, TX, USA.
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Abstract
The last decade has seen a proliferation of tissue clearing methods that render large biological samples transparent and allow unprecedented three-dimensional views of enormous volumes of tissue. For a scientist wondering whether these methods will be useful to address their research problems, it can be bewildering to sort through the ever-increasing number of papers introducing new clearing methods. Here, I provide a concise summary for the novice describing what tissue clearing is, which research problems it can be applied to, how to decide on a clearing method, and where the field is headed in the future.
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Affiliation(s)
- Pablo Ariel
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, United States.
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Abstract
Imaging of fluorescent proteins in whole-mount tissue is a powerful tool to understand growth and developmental processes, not only in plants. With the advent of genetically encoded fluorescent reporters, which specifically label reproductive cells in Arabidopsis, deep tissue imaging has become increasingly important for the study of plant reproduction. To penetrate the surrounding layers of maternal tissue, however, the tissue has to be cleared by homogenizing the refractive index of the sample, often leading to inactivation of fluorescent proteins. 2,2'-thiodiethanol (TDE) has recently been introduced as a clearing agent that allows the imaging of fluorescent proteins in a cleared plant tissue. Here, we describe a simple protocol that combines TDE-based tissue clearing with cell wall staining to outline cells that enable deep tissue imaging in reproductive structures of Arabidopsis thaliana.
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Affiliation(s)
- Daniel Slane
- Department of Cell Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076, Tuebingen, Germany
| | - Patrick Bürgel
- Department of Cell Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076, Tuebingen, Germany
| | - Martin Bayer
- Department of Cell Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076, Tuebingen, Germany.
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21
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Žygelytė E, Bernard ME, Tomlinson JE, Martin MJ, Terhorst A, Bradford HE, Lundquist SA, Sledziona M, Cheetham J. RetroDISCO: Clearing technique to improve quantification of retrograde labeled motor neurons of intact mouse spinal cords. J Neurosci Methods 2016; 271:34-42. [PMID: 27268155 PMCID: PMC5620662 DOI: 10.1016/j.jneumeth.2016.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 05/16/2016] [Accepted: 05/31/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND Quantification of the number of axons reinnervating a target organ is often used to assess regeneration after peripheral nerve repair, but because of axonal branching, this method can overestimate the number of motor neurons regenerating across an injury. Current methods to count the number of regenerated motor neurons include retrograde labeling followed by cryosectioning and counting labeled motor neuron cell bodies, however, the process of sectioning introduces error from potential double counting of cells in adjacent sections. NEW METHOD We describe a method, retroDISCO, that optically clears whole mouse spinal cord without loss of fluorescent signal to allow imaging of retrograde labeled motor neurons using confocal microscopy. RESULTS Complete optical clearing of spinal cords takes four hours and confocal microscopy can obtain z-stacks of labeled motor neuron pools within 3-5min. The technique is able to detect anticipated differences in motor neuron number after cross-suture and conduit repair compared to intact mice and is highly repeatable. COMPARISON WITH EXISTING METHOD RetroDISCO is inexpensive, simple, robust and uses commonly available microscopy techniques to determine the number of motor neurons extending axons across an injury site, avoiding the need for labor-intensive cryosectioning and potential double counting of motor neuron cell bodies in adjacent sections. CONCLUSIONS RetroDISCO allows rapid quantification of the degree of reinnervation without the confounding produced by axonal sprouting.
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Affiliation(s)
- Emilija Žygelytė
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Megan E Bernard
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Joy E Tomlinson
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Matthew J Martin
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Allegra Terhorst
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Harriet E Bradford
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States; The Royal Veterinary College, University of London, North Mymms, Hertfordshire, UK
| | - Sarah A Lundquist
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Michael Sledziona
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States; The Royal Veterinary College, University of London, North Mymms, Hertfordshire, UK
| | - Jonathan Cheetham
- Department of Clinical Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY, United States.
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22
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Sommer G, Schriefl AJ, Andrä M, Sacherer M, Viertler C, Wolinski H, Holzapfel GA. Biomechanical properties and microstructure of human ventricular myocardium. Acta Biomater 2015; 24:172-92. [PMID: 26141152 DOI: 10.1016/j.actbio.2015.06.031] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/12/2015] [Accepted: 06/24/2015] [Indexed: 11/23/2022]
Abstract
In the multidisciplinary field of heart research it is of utmost importance to identify accurate myocardium material properties for the description of phenomena such as mechano-electric feedback or heart wall thickening. A rationally-based material model is required to understand the highly nonlinear mechanics of complex structures such as the passive myocardium under different loading conditions. Unfortunately, to date there are no experimental data of human heart tissues available to estimate material parameters and to develop adequate material models. This study aimed to determine biaxial extension and triaxial shear properties and the underlying microstructure of the passive human ventricular myocardium. Using new state-of-the-art equipment, planar biaxial extension tests were performed to determine the biaxial extension properties of the passive ventricular human myocardium. Shear properties of the myocardium were examined by triaxial simple shear tests performed on small cubic specimens excised from an adjacent region of the biaxial extension specimens. The three-dimensional microstructure was investigated through second-harmonic generation (SHG) microscopy on optically cleared tissues, which emphasized the 3D orientation and dispersion of the myofibers and adjacent collagen fabrics. The results suggest that the passive human LV myocardium under quasi-static and dynamic multiaxial loadings is a nonlinear, anisotropic (orthotropic), viscoelastic and history-dependent soft biological material undergoing large deformations. Material properties of the tissue components along local microstructural axes drive the nonlinear and orthotropic features of the myocardium. SHG microscopy investigation revealed detailed information about the myocardial microstructure due to its high resolution. It enabled the identification of structural parameters such as the fiber and the sheet orientations and corresponding dispersions. With this complete set of material data, a sophisticated material model and associated material parameters can be defined for a better description of the biomechanical response of the ventricular myocardium in humans. Such a model will lead to more accurate computational simulations to better understand the fundamental underlying ventricular mechanics, a step needed in the improvement of medical treatment of heart diseases. STATEMENT OF SIGNIFICANCE Unfortunately, to date there are no experimental data of human heart tissues available for material parameter estimation and the development of adequate material models. In this manuscript novel biaxial tensile and shear test data at different specimen orientations are presented, which allowed to adequately capture the direction-dependent material response. With these complete sets of mechanical data, combined with their underlying microstructural data (also presented herein), sophisticated material models and associated material parameters can be defined for the description of the mechanical behavior of the ventricular myocardium in humans. Such models will lead to accurate computational simulations to better understand the fundamental underlying ventricular mechanics, a step needed in the improvement of medical treatment of heart diseases.
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Tyson AL, Hilton ST, Andreae LC. Rapid, simple and inexpensive production of custom 3D printed equipment for large-volume fluorescence microscopy. Int J Pharm 2015; 494:651-656. [PMID: 25797056 PMCID: PMC4626572 DOI: 10.1016/j.ijpharm.2015.03.042] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/18/2015] [Indexed: 11/26/2022]
Abstract
The cost of 3D printing has reduced dramatically over the last few years and is now within reach of many scientific laboratories. This work presents an example of how 3D printing can be applied to the development of custom laboratory equipment that is specifically adapted for use with the novel brain tissue clearing technique, CLARITY. A simple, freely available online software tool was used, along with consumer-grade equipment, to produce a brain slicing chamber and a combined antibody staining and imaging chamber. Using standard 3D printers we were able to produce research-grade parts in an iterative manner at a fraction of the cost of commercial equipment. 3D printing provides a reproducible, flexible, simple and cost-effective method for researchers to produce the equipment needed to quickly adopt new methods.
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Affiliation(s)
- Adam L Tyson
- MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK; Department of Forensic and Neurodevelopmental Science, King's College London, London SE5 8AF, UK.
| | - Stephen T Hilton
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, London WC1N 1AX, UK.
| | - Laura C Andreae
- MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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