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Faubert AC, Larina IV, Wang S. Open-source, highly efficient, post-acquisition synchronization for 4D dual-contrast imaging of the mouse embryonic heart over development with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:163-181. [PMID: 36698661 PMCID: PMC9842004 DOI: 10.1364/boe.475027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 05/28/2023]
Abstract
Dynamic imaging of the beating embryonic heart in 3D is critical for understanding cardiac development and defects. Optical coherence tomography (OCT) plays an important role in embryonic heart imaging with its unique imaging scale and label-free contrasts. In particular, 4D (3D + time) OCT imaging enabled biomechanical analysis of the developing heart in various animal models. While ultrafast OCT systems allow for direct volumetric imaging of the beating heart, the imaging speed remains limited, leading to an image quality inferior to that produced by post-acquisition synchronization. As OCT systems become increasingly available to a wide range of biomedical researchers, a more accessible 4D reconstruction method is required to enable the broader application of OCT in the dynamic, volumetric assessment of embryonic heartbeat. Here, we report an open-source, highly efficient, post-acquisition synchronization method for 4D cardiodynamic and hemodynamic imaging of the mouse embryonic heart. Relying on the difference between images to characterize heart wall movements, the method provides good sensitivity to the cardiac activity when aligning heartbeat phases, even at early stages when the heart wall occupies only a small number of pixels. The method works with a densely sampled single 3D data acquisition, which, unlike the B-M scans required by other methods, is readily available in most commercial OCT systems. Compared with an existing approach for the mouse embryonic heart, this method shows superior reconstruction quality. We present the robustness of the method through results from different embryos with distinct heart rates, ranging from 1.24 Hz to 2.13 Hz. Since the alignment process operates on a 1D signal, the method has a high efficiency, featuring sub-second alignment time while utilizing ∼100% of the original image files. This allows us to achieve repeated, dual-contrast imaging of mouse embryonic heart development. This new, open-source method could facilitate research using OCT to study early cardiogenesis.
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Affiliation(s)
- Andre C. Faubert
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Irina V. Larina
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
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2
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Ma Y, Li C, Jiang H, Zhao Y, Liu J, Yu Y, Wang Y, Shi W, Ma Z. OCT based four-dimensional cardiac imaging of a living chick embryo using an impedance signal as a gating for post-acquisition synchronization. BIOMEDICAL OPTICS EXPRESS 2022; 13:6595-6609. [PMID: 36589591 PMCID: PMC9774874 DOI: 10.1364/boe.476254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Optical coherence tomography (OCT) is a non-invasive imaging modality with high spatial resolution suitable for early embryonic heart imaging. However, the most commonly used OCT systems cannot provide direct 4-D imaging due to acquisition speed limitations. We proposed a retrospective gating 4-D reconstruction method based on spectral domain OCT. A special circuit was designed to measure the impedance change of chick embryos in response to the heart beating. The impedance signal was acquired simultaneously with the OCT B-scan image sequence at several different locations along the heart. The impedance signal was used as a gating for 4-D reconstruction. The reconstruction algorithm includes cardiac period calculation, interpolation from multi-cardiac cycle image sequence into one cardiac cycle, and cardiac phase synchronization among the different locations of the heart. The synchronism of the impedance signal change with the heartbeat was verified. Using the proposed method, we reconstructed the cardiac outflow tract (OFT) of chick embryos at an early stage of development (Hamburger-Hamilton stage 18). We showed that the reconstructed 4-D images correctly captured the dynamics of the OFT wall motion.
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Affiliation(s)
- Yushu Ma
- School of Computer Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Chuanxi Li
- Hangzhou Xinrui Medical Technology Co., Ltd, No. 22 Xinyan Road, Hangzhou 311100, China
| | - Huiwen Jiang
- College of Information Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Yuqian Zhao
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Jian Liu
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Yao Yu
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Yi Wang
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
| | - Wenbo Shi
- School of Computer Science and Engineering, Northeastern University, No. 311 Wenhua Road, Shenyang 110169, China
| | - Zhenhe Ma
- Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University, No. 143 Taishan Road, Qinhuangdao 066004, China
- School of Control Engineering, Northeastern University at Qinhuangdao, No. 143 Taishan Road, Qinhuangdao 066004, China
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3
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Scully DM, Larina IV. Mouse embryo phenotyping with optical coherence tomography. Front Cell Dev Biol 2022; 10:1000237. [PMID: 36158219 PMCID: PMC9500480 DOI: 10.3389/fcell.2022.1000237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/26/2022] [Indexed: 01/25/2023] Open
Abstract
With the explosion of gene editing tools in recent years, there has been a much greater demand for mouse embryo phenotyping, and traditional methods such as histology and histochemistry experienced a methodological renaissance as they became the principal tools for phenotyping. However, it is important to explore alternative phenotyping options to maximize time and resources and implement volumetric structural analysis for enhanced investigation of phenotypes. Cardiovascular phenotyping, in particular, is important to perform in vivo due to the dramatic structural and functional changes that occur in heart development over relatively short periods of time. Optical coherence tomography (OCT) is one of the most exciting advanced imaging techniques emerging within the field of developmental biology, and this review provides a summary of how it is currently being implemented in mouse embryo investigations and phenotyping. This review aims to provide an understanding of the approaches used in optical coherence tomography and how they can be applied in embryology and developmental biology, with the overall aim of bridging the gap between biology and technology.
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Wang S, Larina IV. Following the Beat: Imaging the Valveless Pumping Function in the Early Embryonic Heart. J Cardiovasc Dev Dis 2022; 9:jcdd9080267. [PMID: 36005431 PMCID: PMC9409458 DOI: 10.3390/jcdd9080267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/26/2022] Open
Abstract
In vertebrates, the coordinated beat of the early heart tube drives cardiogenesis and supports embryonic growth. How the heart pumps at this valveless stage marks a fascinating problem that is of vital significance for understanding cardiac development and defects. The developing heart achieves its function at the same time as continuous and dramatic morphological changes, which in turn modify its pumping dynamics. The beauty of this muti-time-scale process also highlights its complexity that requires interdisciplinary approaches to study. High-resolution optical imaging, particularly fast, four-dimensional (4D) imaging, plays a critical role in revealing the process of pumping, instructing numerical modeling, and enabling biomechanical analyses. In this review, we aim to connect the investigation of valveless pumping mechanisms with the recent advancements in embryonic cardiodynamic imaging, facilitating interactions between these two areas of study, in hopes of encouraging and motivating innovative work to further understand the early heartbeat.
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Affiliation(s)
- Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
- Correspondence:
| | - Irina V. Larina
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
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5
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Marques IJ, Ernst A, Arora P, Vianin A, Hetke T, Sanz-Morejón A, Naumann U, Odriozola A, Langa X, Andrés-Delgado L, Zuber B, Torroja C, Osterwalder M, Simões FC, Englert C, Mercader N. Wt1 transcription factor impairs cardiomyocyte specification and drives a phenotypic switch from myocardium to epicardium. Development 2022; 149:274789. [DOI: 10.1242/dev.200375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/16/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
During development, the heart grows by addition of progenitor cells to the poles of the primordial heart tube. In the zebrafish, Wilms tumor 1 transcription factor a (wt1a) and b (wt1b) genes are expressed in the pericardium, at the venous pole of the heart. From this pericardial layer, the proepicardium emerges. Proepicardial cells are subsequently transferred to the myocardial surface and form the epicardium, covering the myocardium. We found that while wt1a and wt1b expression is maintained in proepicardial cells, it is downregulated in pericardial cells that contribute cardiomyocytes to the developing heart. Sustained wt1b expression in cardiomyocytes reduced chromatin accessibility of specific genomic loci. Strikingly, a subset of wt1a- and wt1b-expressing cardiomyocytes changed their cell-adhesion properties, delaminated from the myocardium and upregulated epicardial gene expression. Thus, wt1a and wt1b act as a break for cardiomyocyte differentiation, and ectopic wt1a and wt1b expression in cardiomyocytes can lead to their transdifferentiation into epicardial-like cells.
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Affiliation(s)
- Ines J. Marques
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern 3008, Switzerland
| | - Alexander Ernst
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern 3008, Switzerland
| | - Prateek Arora
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern 3008, Switzerland
| | - Andrej Vianin
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
| | - Tanja Hetke
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
| | - Andrés Sanz-Morejón
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
- Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid 28029, Spain
| | - Uta Naumann
- Leibniz Institute on Aging-Fritz Lipmann Institute, Jena 07745, Germany
| | - Adolfo Odriozola
- Department of Microscopic Anatomy and Structural Biology, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
| | - Xavier Langa
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
| | | | - Benoît Zuber
- Department of Microscopic Anatomy and Structural Biology, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
| | - Carlos Torroja
- Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid 28029, Spain
| | - Marco Osterwalder
- Department for BioMedical Research (DBMR), University of Bern, Bern 3008, Switzerland
- Department of Cardiology, Bern University Hospital, 3010 Bern, Switzerland
| | - Filipa C. Simões
- MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
- Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Christoph Englert
- Leibniz Institute on Aging-Fritz Lipmann Institute, Jena 07745, Germany
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Jena 07745, Germany
| | - Nadia Mercader
- Department of Developmental Biology and Regeneration, Institute of Anatomy, University of Bern, Bern 3012, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern 3008, Switzerland
- Centro Nacional de Investigaciones Cardiovasculares CNIC, Madrid 28029, Spain
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6
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Hallab JC, Nim HT, Stolper J, Chahal G, Waylen L, Bolk F, Elliott DA, Porrello E, Ramialison M. Towards spatio-temporally resolved developmental cardiac gene regulatory networks in zebrafish. Brief Funct Genomics 2021:elab030. [PMID: 34170300 DOI: 10.1093/bfgp/elab030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/13/2021] [Accepted: 05/26/2021] [Indexed: 12/25/2022] Open
Abstract
Heart formation in the zebrafish involves a rapid, complex series of morphogenetic events in three-dimensional space that spans cardiac lineage specification through to chamber formation and maturation. This process is tightly orchestrated by a cardiac gene regulatory network (GRN), which ensures the precise spatio-temporal deployment of genes critical for heart formation. Alterations of the timing or spatial localisation of gene expression can have a significant impact in cardiac ontogeny and may lead to heart malformations. Hence, a better understanding of the cellular and molecular basis of congenital heart disease relies on understanding the behaviour of cardiac GRNs with precise spatiotemporal resolution. Here, we review the recent technical advances that have expanded our capacity to interrogate the cardiac GRN in zebrafish. In particular, we focus on studies utilising high-throughput technologies to systematically dissect gene expression patterns, both temporally and spatially during heart development.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Mirana Ramialison
- Australian Regenerative Medicine Institute and Systems Biology Institute Australia, Monash University, Clayton, VIC, Australia
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Campinho P, Lamperti P, Boselli F, Vilfan A, Vermot J. Blood Flow Limits Endothelial Cell Extrusion in the Zebrafish Dorsal Aorta. Cell Rep 2021; 31:107505. [PMID: 32294443 DOI: 10.1016/j.celrep.2020.03.069] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/16/2019] [Accepted: 03/21/2020] [Indexed: 12/29/2022] Open
Abstract
Blood flow modulates endothelial cell (EC) response during angiogenesis. Shear stress is known to control gene expression related to the endothelial-mesenchymal transition and endothelial-hematopoietic transition. However, the impact of blood flow on the cellular processes associated with EC extrusion is less well understood. To address this question, we dynamically record EC movements and use 3D quantitative methods to segregate the contributions of various cellular processes to the cellular trajectories in the zebrafish dorsal aorta. We find that ECs spread toward the cell extrusion area following the tissue deformation direction dictated by flow-derived mechanical forces. Cell extrusion increases when blood flow is impaired. Similarly, the mechanosensor polycystic kidney disease 2 (pkd2) limits cell extrusion, suggesting that ECs actively sense mechanical forces in the process. These findings identify pkd2 and flow as critical regulators of EC extrusion and suggest that mechanical forces coordinate this process by maintaining ECs within the endothelium.
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Affiliation(s)
- Pedro Campinho
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Paola Lamperti
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Francesco Boselli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Andrej Vilfan
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany; J. Stefan Institute, Ljubljana, Slovenia
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Université de Strasbourg, Illkirch, France; Department of Bioengineering, Imperial College London, London, UK.
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8
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Salehin N, Villarreal C, Teranikar T, Dubansky B, Lee J, Chuong CJ. Assessing Pressure-Volume Relationship in Developing Heart of Zebrafish In-Vivo. Ann Biomed Eng 2021; 49:2080-2093. [PMID: 33532949 DOI: 10.1007/s10439-021-02731-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
During embryogenesis, the developing heart transforms from a linear peristaltic tube into a multi-chambered pulsatile pump with blood flow-regulating valves. In this work, we report how hemodynamic parameters evolve during the heart's development, leading to its rhythmic pumping and blood flow regulation as a functioning organ. We measured the time course of intra-ventricular pressure from zebrafish embryos at 3, 4, and 5 days post fertilization (dpf) using the servo null method. We also measured the ventricular volume and monitored the opening/closing activity of the AV and VB valves using 4D selective plane illumination microscopy (SPIM). Our results revealed significant increases in peak systolic pressure, stroke volume and work, cardiac output, and power generation, and a total peripheral resistance decrease from zebrafish at 4, 5 dpf versus 3 dpf. These data illustrate that the early-stage zebrafish heart's increasing efficiency is synchronous with the expected changes in valve development, chamber morphology and increasing vascular network complexity. Such physiological measurements in tractable laboratory model organisms are critical for understanding how gene variants may affect phenotype. As the zebrafish emerges as a leading biomedical model organism, the ability to effectively measure its physiology is critical to its translational relevance.
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Affiliation(s)
- Nabid Salehin
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76010, USA
| | - Cameron Villarreal
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76010, USA
| | - Tanveer Teranikar
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76010, USA
| | - Benjamin Dubansky
- Department of Biological Sciences, University of North Texas, Denton, TX, 76201, USA
| | - Juhyun Lee
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76010, USA
| | - Cheng-Jen Chuong
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76010, USA.
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9
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Lopez AL, Wang S, Larina IV. Embryonic Mouse Cardiodynamic OCT Imaging. J Cardiovasc Dev Dis 2020; 7:E42. [PMID: 33020375 PMCID: PMC7712379 DOI: 10.3390/jcdd7040042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022] Open
Abstract
The embryonic heart is an active and developing organ. Genetic studies in mouse models have generated great insight into normal heart development and congenital heart defects, and suggest mechanical forces such as heart contraction and blood flow to be implicated in cardiogenesis and disease. To explore this relationship and investigate the interplay between biomechanical forces and cardiac development, live dynamic cardiac imaging is essential. Cardiodynamic imaging with optical coherence tomography (OCT) is proving to be a unique approach to functional analysis of the embryonic mouse heart. Its compatibility with live culture systems, reagent-free contrast, cellular level resolution, and millimeter scale imaging depth make it capable of imaging the heart volumetrically and providing spatially resolved information on heart wall dynamics and blood flow. Here, we review the progress made in mouse embryonic cardiodynamic imaging with OCT, highlighting leaps in technology to overcome limitations in resolution and acquisition speed. We describe state-of-the-art functional OCT methods such as Doppler OCT and OCT angiography for blood flow imaging and quantification in the beating heart. As OCT is a continuously developing technology, we provide insight into the future developments of this area, toward the investigation of normal cardiogenesis and congenital heart defects.
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Affiliation(s)
- Andrew L. Lopez
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
| | - Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA;
| | - Irina V. Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
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10
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Wang S, Larina IV. Live mechanistic assessment of localized cardiac pumping in mammalian tubular embryonic heart. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-19. [PMID: 32762173 PMCID: PMC7403774 DOI: 10.1117/1.jbo.25.8.086001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/23/2020] [Indexed: 06/01/2023]
Abstract
SIGNIFICANCE Understanding how the valveless embryonic heart pumps blood is essential to elucidate biomechanical cues regulating cardiogenesis, which is important for the advancement of congenital heart defects research. However, methods capable of embryonic cardiac pumping analysis remain limited, and assessing this highly dynamic process in mammalian embryos is challenging. New approaches are critically needed to address this hurdle. AIM We report an imaging-based approach for functional assessment of localized pumping dynamics in the early tubular embryonic mouse heart. APPROACH Four-dimensional optical coherence tomography was used to obtain structural and Doppler hemodynamic imaging of the beating heart in live mouse embryos at embryonic day 9.25. The pumping assessment was performed based on the volumetric blood flow rate, flow resistance within the heart tube, and pressure gradient induced by heart wall movements. The relation between the blood flow, the pressure gradient, and the resistance to flow were evaluated through temporal analyses and Granger causality test. RESULTS In the ventricles, our method revealed connections between the temporal profiles of pressure gradient and volumetric blood flow rate. Statistically significant causal relation from the pressure gradient to the blood flow was demonstrated. Our analysis also suggests that cardiac pumping in the early ventricles is a combination of suction and pushing. In contrast, in the outflow tract, where the conduction wave is slower than the blood flow, we did not find significant causal relation from pressure to flow, suggesting that, different from ventricular regions, the local active contraction of the outflow tract is unlikely to drive the flow in that region. CONCLUSIONS We present an imaging-based approach that enables localized assessment of pumping dynamics in the mouse tubular embryonic heart. This method creates a new opportunity for functional analysis of the pumping mechanism underlying the developing mammalian heart at early stages and could be useful for studying biomechanical changes in mutant embryonic hearts that model congenital heart defects.
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Affiliation(s)
- Shang Wang
- Stevens Institute of Technology, Department of Biomedical Engineering, Hoboken, New Jersey, USA
| | - Irina V. Larina
- Baylor College of Medicine, Department of Molecular Physiology and Biophysics, Houston, Texas, USA
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11
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Keller BB, Kowalski WJ, Tinney JP, Tobita K, Hu N. Validating the Paradigm That Biomechanical Forces Regulate Embryonic Cardiovascular Morphogenesis and Are Fundamental in the Etiology of Congenital Heart Disease. J Cardiovasc Dev Dis 2020; 7:E23. [PMID: 32545681 PMCID: PMC7344498 DOI: 10.3390/jcdd7020023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/31/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
The goal of this review is to provide a broad overview of the biomechanical maturation and regulation of vertebrate cardiovascular (CV) morphogenesis and the evidence for mechanistic relationships between function and form relevant to the origins of congenital heart disease (CHD). The embryonic heart has been investigated for over a century, initially focusing on the chick embryo due to the opportunity to isolate and investigate myocardial electromechanical maturation, the ability to directly instrument and measure normal cardiac function, intervene to alter ventricular loading conditions, and then investigate changes in functional and structural maturation to deduce mechanism. The paradigm of "Develop and validate quantitative techniques, describe normal, perturb the system, describe abnormal, then deduce mechanisms" was taught to many young investigators by Dr. Edward B. Clark and then validated by a rapidly expanding number of teams dedicated to investigate CV morphogenesis, structure-function relationships, and pathogenic mechanisms of CHD. Pioneering studies using the chick embryo model rapidly expanded into a broad range of model systems, particularly the mouse and zebrafish, to investigate the interdependent genetic and biomechanical regulation of CV morphogenesis. Several central morphogenic themes have emerged. First, CV morphogenesis is inherently dependent upon the biomechanical forces that influence cell and tissue growth and remodeling. Second, embryonic CV systems dynamically adapt to changes in biomechanical loading conditions similar to mature systems. Third, biomechanical loading conditions dynamically impact and are regulated by genetic morphogenic systems. Fourth, advanced imaging techniques coupled with computational modeling provide novel insights to validate regulatory mechanisms. Finally, insights regarding the genetic and biomechanical regulation of CV morphogenesis and adaptation are relevant to current regenerative strategies for patients with CHD.
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Affiliation(s)
- Bradley B. Keller
- Cincinnati Children’s Heart Institute, Greater Louisville and Western Kentucky Practice, Louisville, KY 40202, USA
| | - William J. Kowalski
- Laboratory of Stem Cell and Neuro-Vascular Biology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA;
| | - Joseph P. Tinney
- Kosair Charities Pediatric Heart Research Program, Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40202, USA;
| | - Kimimasa Tobita
- Department of Medical Affairs, Abiomed Japan K.K., Muromachi Higashi Mitsui Bldg, Tokyo 103-0022, Japan;
| | - Norman Hu
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84108, USA;
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Wang S, Larina IV, Larin KV. Label-free optical imaging in developmental biology [Invited]. BIOMEDICAL OPTICS EXPRESS 2020; 11:2017-2040. [PMID: 32341864 PMCID: PMC7173889 DOI: 10.1364/boe.381359] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/30/2020] [Accepted: 02/25/2020] [Indexed: 05/03/2023]
Abstract
Application of optical imaging in developmental biology marks an exciting frontier in biomedical optics. Optical resolution and imaging depth allow for investigation of growing embryos at subcellular, cellular, and whole organism levels, while the complexity and variety of embryonic processes set multiple challenges stimulating the development of various live dynamic embryonic imaging approaches. Among other optical methods, label-free optical techniques attract an increasing interest as they allow investigation of developmental mechanisms without application of exogenous markers or fluorescent reporters. There has been a boost in development of label-free optical imaging techniques for studying embryonic development in animal models over the last decade, which revealed new information about early development and created new areas for investigation. Here, we review the recent progress in label-free optical embryonic imaging, discuss specific applications, and comment on future developments at the interface of photonics, engineering, and developmental biology.
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Affiliation(s)
- Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, NJ 07030, USA
| | - Irina V. Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Kirill V. Larin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, TX 77204, USA
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13
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Adaptive prospective optical gating enables day-long 3D time-lapse imaging of the beating embryonic zebrafish heart. Nat Commun 2019; 10:5173. [PMID: 31729395 PMCID: PMC6858381 DOI: 10.1038/s41467-019-13112-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022] Open
Abstract
Three-dimensional fluorescence time-lapse imaging of the beating heart is extremely challenging, due to the heart’s constant motion and a need to avoid pharmacological or phototoxic damage. Although real-time triggered imaging can computationally “freeze” the heart for 3D imaging, no previous algorithm has been able to maintain phase-lock across developmental timescales. We report a new algorithm capable of maintaining day-long phase-lock, permitting routine acquisition of synchronised 3D + time video time-lapse datasets of the beating zebrafish heart. This approach has enabled us for the first time to directly observe detailed developmental and cellular processes in the beating heart, revealing the dynamics of the immune response to injury and witnessing intriguing proliferative events that challenge the established literature on cardiac trabeculation. Our approach opens up exciting new opportunities for direct time-lapse imaging studies over a 24-hour time course, to understand the cellular mechanisms underlying cardiac development, repair and regeneration. Imaging heart development is challenging due to constant tissue movement and changing physical landmarks. Here the authors present an algorithm capable of maintaining phase-locked imaging throughout a 24 hour timespan, enabling long term timelapse imaging studies of zebrafish heart development, repair and regeneration.
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14
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Marrese M, Antonovaite N, Nelemans BK, Smit TH, Iannuzzi D. Micro-indentation and optical coherence tomography for the mechanical characterization of embryos: Experimental setup and measurements on chicken embryos. Acta Biomater 2019; 97:524-534. [PMID: 31377425 DOI: 10.1016/j.actbio.2019.07.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
Abstract
The investigation of the mechanical properties of embryos is expected to provide valuable information on the phenomenology of morphogenesis. It is thus believed that, by mapping the viscoelastic features of an embryo at different stages of growth, it may be possible to shed light on the role of mechanics in embryonic development. To contribute to this field, we present a new instrument that can determine spatiotemporal distributions of mechanical properties of embryos over a wide area and with unprecedented accuracy. The method relies on combining ferrule-top micro-indentation, which provides local measurements of viscoelasticity, with Optical Coherence Tomography, which can reveal changes in tissue morphology and help the user identify the indentation point. To prove the working principle, we have collected viscoelasticity maps of fixed and live HH11-HH12 chicken embryos. Our study shows that the instrument can reveal correlations between tissue morphology and mechanical behavior. STATEMENT OF SIGNIFICANCE: Local mechanical properties of soft biological tissue play a crucial role in several biological processes, including cell differentiation, cell migration, and body formation; therefore, measuring tissue properties at high resolution is of great interest in biology and tissue engineering. To provide an efficient method for the biomechanical characterization of soft biological tissues, we introduce a new tool in which the combination of non-invasive Optical Coherence Tomography imaging and depth-controlled indentation measurements allows one to map the viscoelastic properties of biological tissue and investigate correlations between local mechanical features and tissue morphology with unprecedented resolution.
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15
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Vortex Dynamics in Trabeculated Embryonic Ventricles. J Cardiovasc Dev Dis 2019; 6:jcdd6010006. [PMID: 30678229 PMCID: PMC6463151 DOI: 10.3390/jcdd6010006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/03/2023] Open
Abstract
Proper heart morphogenesis requires a delicate balance between hemodynamic forces, myocardial activity, morphogen gradients, and epigenetic signaling, all of which are coupled with genetic regulatory networks. Recently both in vivo and in silico studies have tried to better understand hemodynamics at varying stages of veretebrate cardiogenesis. In particular, the intracardial hemodynamics during the onset of trabeculation is notably complex—the inertial and viscous fluid forces are approximately equal at this stage and small perturbations in morphology, scale, and steadiness of the flow can lead to significant changes in bulk flow structures, shear stress distributions, and chemical morphogen gradients. The immersed boundary method was used to numerically simulate fluid flow through simplified two-dimensional and stationary trabeculated ventricles of 72, 80, and 120 h post fertilization wild type zebrafish embryos and ErbB2-inhibited embryos at seven days post fertilization. A 2D idealized trabeculated ventricular model was also used to map the bifurcations in flow structure that occur as a result of the unsteadiness of flow, trabeculae height, and fluid scale (Re). Vortex formation occurred in intertrabecular regions for biologically relevant parameter spaces, wherein flow velocities increased. This indicates that trabecular morphology may alter intracardial flow patterns and hence ventricular shear stresses and morphogen gradients. A potential implication of this work is that the onset of vortical (disturbed) flows can upregulate Notch1 expression in endothelial cells in vivo and hence impacts chamber morphogenesis, valvulogenesis, and the formation of the trabeculae themselves. Our results also highlight the sensitivity of cardiac flow patterns to changes in morphology and blood rheology, motivating efforts to obtain spatially and temporally resolved chamber geometries and kinematics as well as the careful measurement of the embryonic blood rheology. The results also suggest that there may be significant changes in shear signalling due to morphological and mechanical variation across individuals and species.
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16
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Abstract
Heart formation involves a complex series of tissue rearrangements, during which regions of the developing organ expand, bend, converge, and protrude in order to create the specific shapes of important cardiac components. Much of this morphogenesis takes place while cardiac function is underway, with blood flowing through the rapidly contracting chambers. Fluid forces are therefore likely to influence the regulation of cardiac morphogenesis, but it is not yet clear how these biomechanical cues direct specific cellular behaviors. In recent years, the optical accessibility and genetic amenability of zebrafish embryos have facilitated unique opportunities to integrate the analysis of flow parameters with the molecular and cellular dynamics underlying cardiogenesis. Consequently, we are making progress toward a comprehensive view of the biomechanical regulation of cardiac chamber emergence, atrioventricular canal differentiation, and ventricular trabeculation. In this review, we highlight a series of studies in zebrafish that have provided new insight into how cardiac function can shape cardiac morphology, with a particular focus on how hemodynamics can impact cardiac cell behavior. Over the long-term, this knowledge will undoubtedly guide our consideration of the potential causes of congenital heart disease.
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Affiliation(s)
- Pragya Sidhwani
- Division of Biological Sciences, University of California, San Diego, CA, United States
| | - Deborah Yelon
- Division of Biological Sciences, University of California, San Diego, CA, United States.
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17
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Lee J, Vedula V, Baek KI, Chen J, Hsu JJ, Ding Y, Chang CC, Kang H, Small A, Fei P, Chuong CM, Li R, Demer L, Packard RRS, Marsden AL, Hsiai TK. Spatial and temporal variations in hemodynamic forces initiate cardiac trabeculation. JCI Insight 2018; 3:96672. [PMID: 29997298 DOI: 10.1172/jci.insight.96672] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 05/18/2018] [Indexed: 11/17/2022] Open
Abstract
Hemodynamic shear force has been implicated as modulating Notch signaling-mediated cardiac trabeculation. Whether the spatiotemporal variations in wall shear stress (WSS) coordinate the initiation of trabeculation to influence ventricular contractile function remains unknown. Using light-sheet fluorescent microscopy, we reconstructed the 4D moving domain and applied computational fluid dynamics to quantify 4D WSS along the trabecular ridges and in the groves. In WT zebrafish, pulsatile shear stress developed along the trabecular ridges, with prominent endocardial Notch activity at 3 days after fertilization (dpf), and oscillatory shear stress developed in the trabecular grooves, with epicardial Notch activity at 4 dpf. Genetic manipulations were performed to reduce hematopoiesis and inhibit atrial contraction to lower WSS in synchrony with attenuation of oscillatory shear index (OSI) during ventricular development. γ-Secretase inhibitor of Notch intracellular domain (NICD) abrogated endocardial and epicardial Notch activity. Rescue with NICD mRNA restored Notch activity sequentially from the endocardium to trabecular grooves, which was corroborated by observed Notch-mediated cardiomyocyte proliferations on WT zebrafish trabeculae. We also demonstrated in vitro that a high OSI value correlated with upregulated endothelial Notch-related mRNA expression. In silico computation of energy dissipation further supports the role of trabeculation to preserve ventricular structure and contractile function. Thus, spatiotemporal variations in WSS coordinate trabecular organization for ventricular contractile function.
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Affiliation(s)
- Juhyun Lee
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA.,Joint Department of Bioengineering, University of Texas at Arlington/University of Texas Southwestern Medical Center, Arlington, Texas, USA
| | - Vijay Vedula
- Department of Pediatrics and Bioengineering, Stanford University, Stanford, California, USA
| | - Kyung In Baek
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Junjie Chen
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Jeffrey J Hsu
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Yichen Ding
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Chih-Chiang Chang
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Hanul Kang
- Division of Cardiology, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Adam Small
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Peng Fei
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Cheng-Ming Chuong
- Department of Pathology, University of Southern California, Los Angeles, California, USA
| | - Rongsong Li
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - Linda Demer
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA
| | - René R Sevag Packard
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA.,Division of Cardiology, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Alison L Marsden
- Department of Pediatrics and Bioengineering, Stanford University, Stanford, California, USA
| | - Tzung K Hsiai
- Division of Cardiology, Department of Medicine and Bioengineering, UCLA, Los Angeles, California, USA.,Joint Department of Bioengineering, University of Texas at Arlington/University of Texas Southwestern Medical Center, Arlington, Texas, USA.,Division of Cardiology, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA.,Medical Engineering, California Institute of Technology, Pasadena, California, USA
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18
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Kinking and Torsion Can Significantly Improve the Efficiency of Valveless Pumping in Periodically Compressed Tubular Conduits. Implications for Understanding of the Form-Function Relationship of Embryonic Heart Tubes. J Cardiovasc Dev Dis 2017; 4:jcdd4040019. [PMID: 29367548 PMCID: PMC5753120 DOI: 10.3390/jcdd4040019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 01/01/2023] Open
Abstract
Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts.
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19
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Pestel J, Ramadass R, Gauvrit S, Helker C, Herzog W, Stainier DYR. Real-time 3D visualization of cellular rearrangements during cardiac valve formation. Development 2017; 143:2217-27. [PMID: 27302398 DOI: 10.1242/dev.133272] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/26/2016] [Indexed: 12/30/2022]
Abstract
During cardiac valve development, the single-layered endocardial sheet at the atrioventricular canal (AVC) is remodeled into multilayered immature valve leaflets. Most of our knowledge about this process comes from examining fixed samples that do not allow a real-time appreciation of the intricacies of valve formation. Here, we exploit non-invasive in vivo imaging techniques to identify the dynamic cell behaviors that lead to the formation of the immature valve leaflets. We find that in zebrafish, the valve leaflets consist of two sets of endocardial cells at the luminal and abluminal side, which we refer to as luminal cells (LCs) and abluminal cells (ALCs), respectively. By analyzing cellular rearrangements during valve formation, we observed that the LCs and ALCs originate from the atrium and ventricle, respectively. Furthermore, we utilized Wnt/β-catenin and Notch signaling reporter lines to distinguish between the LCs and ALCs, and also found that cardiac contractility and/or blood flow is necessary for the endocardial expression of these signaling reporters. Thus, our 3D analyses of cardiac valve formation in zebrafish provide fundamental insights into the cellular rearrangements underlying this process.
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Affiliation(s)
- Jenny Pestel
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim 61231, Germany
| | - Radhan Ramadass
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim 61231, Germany
| | - Sebastien Gauvrit
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim 61231, Germany
| | - Christian Helker
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim 61231, Germany University of Muenster, Muenster 48149, Germany
| | - Wiebke Herzog
- University of Muenster, Muenster 48149, Germany Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Muenster, Muenster 48149, Germany
| | - Didier Y R Stainier
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim 61231, Germany
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20
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Valveless pumping mechanics of the embryonic heart during cardiac looping: Pressure and flow through micro-PIV. J Biomech 2017; 50:50-55. [DOI: 10.1016/j.jbiomech.2016.11.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/05/2016] [Indexed: 11/23/2022]
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21
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Grant MG, Patterson VL, Grimes DT, Burdine RD. Modeling Syndromic Congenital Heart Defects in Zebrafish. Curr Top Dev Biol 2017; 124:1-40. [DOI: 10.1016/bs.ctdb.2016.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Drew NK, Johnsen NE, Core JQ, Grosberg A. Multiscale Characterization of Engineered Cardiac Tissue Architecture. J Biomech Eng 2016; 138:2552972. [PMID: 27617880 PMCID: PMC6993780 DOI: 10.1115/1.4034656] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 08/26/2016] [Indexed: 11/08/2022]
Abstract
In a properly contracting cardiac muscle, many different subcellular structures are organized into an intricate architecture. While it has been observed that this organization is altered in pathological conditions, the relationship between length-scales and architecture has not been properly explored. In this work, we utilize a variety of architecture metrics to quantify organization and consistency of single structures over multiple scales, from subcellular to tissue scale as well as correlation of organization of multiple structures. Specifically, as the best way to characterize cardiac tissues, we chose the orientational and co-orientational order parameters (COOPs). Similarly, neonatal rat ventricular myocytes were selected for their consistent architectural behavior. The engineered cells and tissues were stained for four architectural structures: actin, tubulin, sarcomeric z-lines, and nuclei. We applied the orientational metrics to cardiac cells of various shapes, isotropic cardiac tissues, and anisotropic globally aligned tissues. With these novel tools, we discovered: (1) the relationship between cellular shape and consistency of self-assembly; (2) the length-scales at which unguided tissues self-organize; and (3) the correlation or lack thereof between organization of actin fibrils, sarcomeric z-lines, tubulin fibrils, and nuclei. All of these together elucidate some of the current mysteries in the relationship between force production and architecture, while raising more questions about the effect of guidance cues on self-assembly function. These types of metrics are the future of quantitative tissue engineering in cardiovascular biomechanics.
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Affiliation(s)
- Nancy K Drew
- Department of Biomedical Engineering, Center for Complex Biological Systems, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, CA 92697 e-mail:
| | - Nicholas E Johnsen
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, CA 92697 e-mail:
| | - Jason Q Core
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, CA 92697 e-mail:
| | - Anna Grosberg
- Department of Biomedical Engineering, Center for Complex Biological Systems, The Edwards Lifesciences Center for Advanced Cardiovascular Technology,Department of Chemical Engineering and Material Science, University of California, Irvine, Irvine, CA 92697 e-mail:
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23
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Wang S, Lakomy DS, Garcia MD, Lopez AL, Larin KV, Larina IV. Four-dimensional live imaging of hemodynamics in mammalian embryonic heart with Doppler optical coherence tomography. JOURNAL OF BIOPHOTONICS 2016; 9:837-47. [PMID: 26996292 PMCID: PMC5152918 DOI: 10.1002/jbio.201500314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/03/2016] [Accepted: 03/01/2016] [Indexed: 05/19/2023]
Abstract
Hemodynamic analysis of the mouse embryonic heart is essential for understanding the functional aspects of early cardiogenesis and advancing the research in congenital heart defects. However, high-resolution imaging of cardiac hemodynamics in mammalian models remains challenging, primarily due to the dynamic nature and deep location of the embryonic heart. Here we report four-dimensional micro-scale imaging of blood flow in the early mouse embryonic heart, enabling time-resolved measurement and analysis of flow velocity throughout the heart tube. Our method uses Doppler optical coherence tomography in live mouse embryo culture, and employs a post-processing synchronization approach to reconstruct three-dimensional data over time at a 100 Hz volume rate. Experiments were performed on live mouse embryos at embryonic day 9.0. Our results show blood flow dynamics inside the beating heart, with the capability for quantitative flow velocity assessment in the primitive atrium, atrioventricular and bulboventricular regions, and bulbus cordis. Combined cardiodynamic and hemodynamic analysis indicates this functional imaging method can be utilized to further investigate the mechanical relationship between blood flow dynamics and cardiac wall movement, bringing new possibilities to study biomechanics in early mammalian cardiogenesis. Four-dimensional live hemodynamic imaging of the mouse embryonic heart at embryonic day 9.0 using Doppler optical coherence tomography, showing directional blood flows in the sinus venosus, primitive atrium, atrioventricular region and vitelline vein.
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Affiliation(s)
- Shang Wang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S
| | - David S Lakomy
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S
| | - Monica D Garcia
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S
| | - Andrew L Lopez
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S
| | - Kirill V Larin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Blvd., 77204, Houston, TX 77204, U.S
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, 634050, Russia
| | - Irina V Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, U.S..
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24
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Steed E, Faggianelli N, Roth S, Ramspacher C, Concordet JP, Vermot J. klf2a couples mechanotransduction and zebrafish valve morphogenesis through fibronectin synthesis. Nat Commun 2016; 7:11646. [PMID: 27221222 PMCID: PMC4894956 DOI: 10.1038/ncomms11646] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 04/15/2016] [Indexed: 12/23/2022] Open
Abstract
The heartbeat and blood flow signal to endocardial cell progenitors through mechanosensitive proteins that modulate the genetic program controlling heart valve morphogenesis. To date, the mechanism by which mechanical forces coordinate tissue morphogenesis is poorly understood. Here we use high-resolution imaging to uncover the coordinated cell behaviours leading to heart valve formation. We find that heart valves originate from progenitors located in the ventricle and atrium that generate the valve leaflets through a coordinated set of endocardial tissue movements. Gene profiling analyses and live imaging reveal that this reorganization is dependent on extracellular matrix proteins, in particular on the expression of fibronectin1b. We show that blood flow and klf2a, a major endocardial flow-responsive gene, control these cell behaviours and fibronectin1b synthesis. Our results uncover a unique multicellular layering process leading to leaflet formation and demonstrate that endocardial mechanotransduction and valve morphogenesis are coupled via cellular rearrangements mediated by fibronectin synthesis.
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Affiliation(s)
- Emily Steed
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67404, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch 67404, France
- Université de Strasbourg, Illkirch 67404, France
| | - Nathalie Faggianelli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67404, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch 67404, France
- Université de Strasbourg, Illkirch 67404, France
| | - Stéphane Roth
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67404, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch 67404, France
- Université de Strasbourg, Illkirch 67404, France
| | - Caroline Ramspacher
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67404, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch 67404, France
- Université de Strasbourg, Illkirch 67404, France
| | - Jean-Paul Concordet
- Muséum National d'Histoire Naturelle, 75231 Paris Cedex 05, France
- CNRS UMR 7196, 75231 Paris Cedex 05, France
- INSERM U1154, 75231 Paris Cedex 05, France
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67404, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch 67404, France
- Université de Strasbourg, Illkirch 67404, France
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25
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Andrés-Delgado L, Mercader N. Interplay between cardiac function and heart development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1707-16. [PMID: 26952935 PMCID: PMC4906158 DOI: 10.1016/j.bbamcr.2016.03.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/29/2016] [Accepted: 03/03/2016] [Indexed: 12/24/2022]
Abstract
Mechanotransduction refers to the conversion of mechanical forces into biochemical or electrical signals that initiate structural and functional remodeling in cells and tissues. The heart is a kinetic organ whose form changes considerably during development and disease. This requires cardiomyocytes to be mechanically durable and able to mount coordinated responses to a variety of environmental signals on different time scales, including cardiac pressure loading and electrical and hemodynamic forces. During physiological growth, myocytes, endocardial and epicardial cells have to adaptively remodel to these mechanical forces. Here we review some of the recent advances in the understanding of how mechanical forces influence cardiac development, with a focus on fluid flow forces. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Laura Andrés-Delgado
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Nadia Mercader
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain; Institute of Anatomy, University of Bern, Bern, Switzerland.
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26
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Hemodynamics driven cardiac valve morphogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1760-6. [PMID: 26608609 DOI: 10.1016/j.bbamcr.2015.11.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 11/22/2022]
Abstract
Mechanical forces are instrumental to cardiovascular development and physiology. The heart beats approximately 2.6 billion times in a human lifetime and heart valves ensure that these contractions result in an efficient, unidirectional flow of the blood. Composed of endocardial cells (EdCs) and extracellular matrix (ECM), cardiac valves are among the most mechanically challenged structures of the body both during and after their development. Understanding how hemodynamic forces modulate cardiovascular function and morphogenesis is key to unraveling the relationship between normal and pathological cardiovascular development and physiology. Most valve diseases have their origins in embryogenesis, either as signs of abnormal developmental processes or the aberrant re-expression of fetal gene programs normally quiescent in adulthood. Here we review recent discoveries in the mechanobiology of cardiac valve development and introduce the latest technologies being developed in the zebrafish, including live cell imaging and optical technologies, as well as modeling approaches that are currently transforming this field. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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27
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Puah WC, Wasser M. Live imaging of muscles in Drosophila metamorphosis: Towards high-throughput gene identification and function analysis. Methods 2015; 96:103-117. [PMID: 26431669 DOI: 10.1016/j.ymeth.2015.09.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 12/16/2022] Open
Abstract
Time-lapse microscopy in developmental biology is an emerging tool for functional genomics. Phenotypic effects of gene perturbations can be studied non-invasively at multiple time points in chronological order. During metamorphosis of Drosophila melanogaster, time-lapse microscopy using fluorescent reporters allows visualization of alternative fates of larval muscles, which are a model for the study of genes related to muscle wasting. While doomed muscles enter hormone-induced programmed cell death, a smaller population of persistent muscles survives to adulthood and undergoes morphological remodeling that involves atrophy in early, and hypertrophy in late pupation. We developed a method that combines in vivo imaging, targeted gene perturbation and image analysis to identify and characterize genes involved in muscle development. Macrozoom microscopy helps to screen for interesting muscle phenotypes, while confocal microscopy in multiple locations over 4-5 days produces time-lapse images that are used to quantify changes in cell morphology. Performing a similar investigation using fixed pupal tissues would be too time-consuming and therefore impractical. We describe three applications of our pipeline. First, we show how quantitative microscopy can track and measure morphological changes of muscle throughout metamorphosis and analyze genes involved in atrophy. Second, our assay can help to identify genes that either promote or prevent histolysis of abdominal muscles. Third, we apply our approach to test new fluorescent proteins as live markers for muscle development. We describe mKO2 tagged Cysteine proteinase 1 (Cp1) and Troponin-I (TnI) as examples of proteins showing developmental changes in subcellular localization. Finally, we discuss strategies to improve throughput of our pipeline to permit genome-wide screens in the future.
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Affiliation(s)
- Wee Choo Puah
- Imaging Informatics Division, Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Republic of Singapore.
| | - Martin Wasser
- Imaging Informatics Division, Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Republic of Singapore.
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Boselli F, Vermot J. Live imaging and modeling for shear stress quantification in the embryonic zebrafish heart. Methods 2015; 94:129-34. [PMID: 26390811 DOI: 10.1016/j.ymeth.2015.09.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/07/2015] [Accepted: 09/17/2015] [Indexed: 01/17/2023] Open
Abstract
Hemodynamic shear stress is sensed by the endocardial cells composing the inner cell layer of the heart, and plays a major role in cardiac morphogenesis. Yet, the underlying hemodynamics and the associated mechanical stimuli experienced by endocardial cells remains poorly understood. Progress in the field has been hampered by the need for high temporal resolution imaging allowing the flow profiles generated in the beating heart to be resolved. To fill this gap, we propose a method to analyze the wall dynamics, the flow field, and the wall shear stress of the developing zebrafish heart. This method combines live confocal imaging and computational fluid dynamics to overcome difficulties related to live imaging of blood flow in the developing heart. To provide an example of the applicability of the method, we discuss the hemodynamic frequency content sensed by endocardial cells at the onset of valve formation, and how the fundamental frequency of the wall shear stress represents a unique mechanical cue to endocardial, heart-valve precursors.
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Affiliation(s)
- Francesco Boselli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964 Illkirch, France; Université de Strasbourg, Illkirch, France.
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964 Illkirch, France; Université de Strasbourg, Illkirch, France.
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29
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Trivedi V, Truong TV, Trinh LA, Holland DB, Liebling M, Fraser SE. Dynamic structure and protein expression of the live embryonic heart captured by 2-photon light sheet microscopy and retrospective registration. BIOMEDICAL OPTICS EXPRESS 2015; 6:2056-66. [PMID: 26114028 PMCID: PMC4473743 DOI: 10.1364/boe.6.002056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/25/2015] [Accepted: 05/01/2015] [Indexed: 05/05/2023]
Abstract
We present an imaging and image reconstruction pipeline that captures the dynamic three-dimensional beating motion of the live embryonic zebrafish heart at subcellular resolution. Live, intact zebrafish embryos were imaged using 2-photon light sheet microscopy, which offers deep and fast imaging at 70 frames per second, and the individual optical sections were assembled into a full 4D reconstruction of the beating heart using an optimized retrospective image registration algorithm. This imaging and reconstruction platform permitted us to visualize protein expression patterns at endogenous concentrations in zebrafish gene trap lines.
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Affiliation(s)
- Vikas Trivedi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
- Translational Imaging Center, University of Southern California, Molecular and Computational Biology, Los Angeles CA 90089, USA
- Equal contribution
| | - Thai V. Truong
- Translational Imaging Center, University of Southern California, Molecular and Computational Biology, Los Angeles CA 90089, USA
- Equal contribution
| | - Le A. Trinh
- Translational Imaging Center, University of Southern California, Molecular and Computational Biology, Los Angeles CA 90089, USA
| | - Daniel B. Holland
- Translational Imaging Center, University of Southern California, Molecular and Computational Biology, Los Angeles CA 90089, USA
| | - Michael Liebling
- Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara CA 93111 USA
- Idiap Research Institute, 1920 Martigny, Switzerland
| | - Scott E. Fraser
- Translational Imaging Center, University of Southern California, Molecular and Computational Biology, Los Angeles CA 90089, USA
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30
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Johnson B, Bark D, Van Herck I, Garrity D, Dasi LP. Altered mechanical state in the embryonic heart results in time-dependent decreases in cardiac function. Biomech Model Mechanobiol 2015; 14:1379-89. [DOI: 10.1007/s10237-015-0681-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 04/29/2015] [Indexed: 01/29/2023]
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31
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Boselli F, Freund JB, Vermot J. Blood flow mechanics in cardiovascular development. Cell Mol Life Sci 2015; 72:2545-59. [PMID: 25801176 PMCID: PMC4457920 DOI: 10.1007/s00018-015-1885-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/25/2015] [Accepted: 03/12/2015] [Indexed: 11/29/2022]
Abstract
Hemodynamic forces are fundamental to development. Indeed, much of cardiovascular morphogenesis reflects a two-way interaction between mechanical forces and the gene network activated in endothelial cells via mechanotransduction feedback loops. As these interactions are becoming better understood in different model organisms, it is possible to identify common mechanogenetic rules, which are strikingly conserved and shared in many tissues and species. Here, we discuss recent findings showing how hemodynamic forces potentially modulate cardiovascular development as well as the underlying fluid and tissue mechanics, with special attention given to the flow characteristics that are unique to the small scales of embryos.
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Affiliation(s)
- Francesco Boselli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France,
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32
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Spatial and temporal features of the growth of a bacterial species colonizing the zebrafish gut. mBio 2014; 5:mBio.01751-14. [PMID: 25516613 PMCID: PMC4271548 DOI: 10.1128/mbio.01751-14] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The vertebrate intestine is home to microbial ecosystems that play key roles in host development and health. Little is known about the spatial and temporal dynamics of these microbial communities, limiting our understanding of fundamental properties, such as their mechanisms of growth, propagation, and persistence. To address this, we inoculated initially germ-free zebrafish larvae with fluorescently labeled strains of an Aeromonas species, representing an abundant genus in the zebrafish gut. Using light sheet fluorescence microscopy to obtain three-dimensional images spanning the gut, we quantified the entire bacterial load, as founding populations grew from tens to tens of thousands of cells over several hours. The data yield the first ever measurements of the growth kinetics of a microbial species inside a live vertebrate intestine and show dynamics that robustly fit a logistic growth model. Intriguingly, bacteria were nonuniformly distributed throughout the gut, and bacterial aggregates showed considerably higher growth rates than did discrete individuals. The form of aggregate growth indicates intrinsically higher division rates for clustered bacteria, rather than surface-mediated agglomeration onto clusters. Thus, the spatial organization of gut bacteria both relative to the host and to each other impacts overall growth kinetics, suggesting that spatial characterizations will be an important input to predictive models of host-associated microbial community assembly. Our intestines are home to vast numbers of microbes that influence many aspects of health and disease. Though we now know a great deal about the constituents of the gut microbiota, we understand very little about their spatial structure and temporal dynamics in humans or in any animal: how microbial populations establish themselves, grow, fluctuate, and persist. To address this, we made use of a model organism, the zebrafish, and a new optical imaging technique, light sheet fluorescence microscopy, to visualize for the first time the colonization of a live, vertebrate gut by specific bacteria with sufficient resolution to quantify the population over a range from a few individuals to tens of thousands of bacterial cells. Our results provide unprecedented measures of bacterial growth kinetics and also show the influence of spatial structure on bacterial populations, which can be revealed only by direct imaging.
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33
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Abstract
The constant motion of the beating heart presents an obstacle to clear optical imaging, especially 3D imaging, in small animals where direct optical imaging would otherwise be possible. Gating techniques exploit the periodic motion of the heart to computationally "freeze" this movement and overcome motion artifacts. Optically gated imaging represents a recent development of this, where image analysis is used to synchronize acquisition with the heartbeat in a completely non-invasive manner. This article will explain the concept of optical gating, discuss a range of different implementation strategies and their strengths and weaknesses. Finally we will illustrate the usefulness of the technique by discussing applications where optical gating has facilitated novel biological findings by allowing 3D in vivo imaging of cardiac myocytes in their natural environment of the beating heart.
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De Luca E, Zaccaria GM, Hadhoud M, Rizzo G, Ponzini R, Morbiducci U, Santoro MM. ZebraBeat: a flexible platform for the analysis of the cardiac rate in zebrafish embryos. Sci Rep 2014. [PMCID: PMC4790192 DOI: 10.1038/srep04898] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Heartbeat measurement is important in assesssing cardiac function because variations in heart rhythm can be the cause as well as an effect of hidden pathological heart conditions. Zebrafish (Danio rerio) has emerged as one of the most useful model organisms for cardiac research. Indeed, the zebrafish heart is easily accessible for optical analyses without conducting invasive procedures and shows anatomical similarity to the human heart. In this study, we present a non-invasive, simple, cost-effective process to quantify the heartbeat in embryonic zebrafish. To achieve reproducibility, high throughput and flexibility (i.e., adaptability to any existing confocal microscope system and with a user-friendly interface that can be easily used by researchers), we implemented this method within a software program. We show here that this platform, called ZebraBeat, can successfully detect heart rate variations in embryonic zebrafish at various developmental stages, and it can record cardiac rate fluctuations induced by factors such as temperature and genetic- and chemical-induced alterations. Applications of this methodology may include the screening of chemical libraries affecting heart rhythm and the identification of heart rhythm variations in mutants from large-scale forward genetic screens.
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35
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Pantazis P, Supatto W. Advances in whole-embryo imaging: a quantitative transition is underway. Nat Rev Mol Cell Biol 2014; 15:327-39. [DOI: 10.1038/nrm3786] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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Lin KY, Chang WT, Lai YC, Liau I. Toward functional screening of cardioactive and cardiotoxic drugs with zebrafish in vivo using pseudodynamic three-dimensional imaging. Anal Chem 2014; 86:2213-20. [PMID: 24456565 DOI: 10.1021/ac403877h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Given the high mortality in patients with cardiovascular diseases and the life-threatening consequences of drugs with unforeseen adverse effects on hearts, a critical evaluation of the pharmacological response of cardiovascular function on model animals is important especially in the early stages of drug development. We report a proof-of-principle study to demonstrate the utility of zebrafish as an analytical platform to predict the cardiac response of new drugs or chemicals on human beings. With pseudodynamic 3D imaging, we derive individual parameters that are central to the cardiac function of zebrafish, including the ventricular stroke volume, ejection fraction, cardiac output, heart rate, diastolic filling function, and ventricular mass. We evaluate both inotropic and chronotropic responses of the heart of zebrafish treated with drugs that are commonly prescribed and possess varied known cardiac activities. We reveal deranged cardiac function of a zebrafish model of cardiomyopathy induced with a cardiotoxic drug. The cardiac function of zebrafish exhibits a pharmacological response similar to that of human beings. We compare also cardiac parameters obtained in this work with those derived with conventional 2D approximation and show that the latter tends to overestimate the cardiac parameters and produces results of greater variation. In view of the growing interest of using zebrafish in both fundamental and translational biomedical research, we envisage that our approach should benefit not only contemporary pharmaceutical development but also exploratory research such as gene, stem cell, or regenerative therapies targeting congenital or acquired heart diseases.
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Affiliation(s)
- Kuen-You Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , Hsinchu 300, Taiwan
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37
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Staudt DW, Liu J, Thorn KS, Stuurman N, Liebling M, Stainier DYR. High-resolution imaging of cardiomyocyte behavior reveals two distinct steps in ventricular trabeculation. Development 2014; 141:585-93. [PMID: 24401373 DOI: 10.1242/dev.098632] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Over the course of development, the vertebrate heart undergoes a series of complex morphogenetic processes that transforms it from a simple myocardial epithelium to the complex 3D structure required for its function. One of these processes leads to the formation of trabeculae to optimize the internal structure of the ventricle for efficient conduction and contraction. Despite the important role of trabeculae in the development and physiology of the heart, little is known about their mechanism of formation. Using 3D time-lapse imaging of beating zebrafish hearts, we observed that the initiation of cardiac trabeculation can be divided into two processes. Before any myocardial cell bodies have entered the trabecular layer, cardiomyocytes extend protrusions that invade luminally along neighboring cell-cell junctions. These protrusions can interact within the trabecular layer to form new cell-cell contacts. Subsequently, cardiomyocytes constrict their abluminal surface, moving their cell bodies into the trabecular layer while elaborating more protrusions. We also examined the formation of these protrusions in trabeculation-deficient animals, including erbb2 mutants, tnnt2a morphants, which lack cardiac contractions and flow, and myh6 morphants, which lack atrial contraction and exhibit reduced flow. We found that, compared with cardiomyocytes in wild-type hearts, those in erbb2 mutants were less likely to form protrusions, those in tnnt2a morphants formed less stable protrusions, and those in myh6 morphants extended fewer protrusions per cell. Thus, through detailed 4D imaging of beating hearts, we have identified novel cellular behaviors underlying cardiac trabeculation.
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Affiliation(s)
- David W Staudt
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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38
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Mao H, Gribble M, Pertsov AM, Shi P. Embryonic heart morphogenesis from confocal microscopy imaging and automatic segmentation. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:293069. [PMID: 24454530 PMCID: PMC3884962 DOI: 10.1155/2013/293069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/14/2013] [Indexed: 11/18/2022]
Abstract
Embryonic heart morphogenesis (EHM) is a complex and dynamic process where the heart transforms from a single tube into a four-chambered pump. This process is of great biological and clinical interest but is still poorly understood for two main reasons. On the one hand, the existing imaging modalities for investigating EHM suffered from either limited penetration depth or limited spatial resolution. On the other hand, current works typically adopted manual segmentation, which was tedious, subjective, and time consuming considering the complexity of developing heart geometry and the large size of images. In this paper, we propose to utilize confocal microscopy imaging with tissue optical immersion clearing technique to image the heart at different stages of development for EHM study. The imaging method is able to produce high spatial resolution images and achieve large penetration depth at the same time. Furthermore, we propose a novel convex active contour model for automatic image segmentation. The model has the ability to deal with intensity fall-off in depth which is characterized by confocal microscopy images. We acquired the images of embryonic quail hearts from day 6 to day 14 of incubation for EHM study. The experimental results were promising and provided us with an insight view of early heart growth pattern and also paved the road for data-driven heart growth modeling.
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Affiliation(s)
- Hongda Mao
- Computational Biomedicine Laboratory, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Megan Gribble
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Arkady M. Pertsov
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Pengcheng Shi
- Computational Biomedicine Laboratory, Rochester Institute of Technology, Rochester, NY 14623, USA
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39
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Fahrbach FO, Voigt FF, Schmid B, Helmchen F, Huisken J. Rapid 3D light-sheet microscopy with a tunable lens. OPTICS EXPRESS 2013; 21:21010-26. [PMID: 24103973 DOI: 10.1364/oe.21.021010] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The in-vivo investigation of highly dynamic biological samples, for example the beating zebrafish heart, requires high-speed volume imaging techniques. Light-sheet microscopy is ideal for such samples as it records high-contrast images of entire planes within large samples at once. However, in order to obtain images of different planes, it has been necessary to move the sample relative to the fixed focal plane of the detection objective lens. This mechanical movement limits speed, precision and may be harmful to the sample. We have built a light-sheet microscope that uses remote focusing with an electrically tunable lens (ETL). Without moving specimen or objective we have thereby achieved flexible volume imaging at much higher speeds than previously reported. Our high-speed microscope delivers 3D snapshots of sensitive biological samples. As an example, we imaged 17 planes within a beating zebrafish heart at 510 frames per second, equivalent to 30 volume scans per second. Movements, shape changes and signals across the entire volume can be followed which has been impossible with existing reconstruction techniques.
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40
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Lee J, Moghadam ME, Kung E, Cao H, Beebe T, Miller Y, Roman BL, Lien CL, Chi NC, Marsden AL, Hsiai TK. Moving domain computational fluid dynamics to interface with an embryonic model of cardiac morphogenesis. PLoS One 2013; 8:e72924. [PMID: 24009714 PMCID: PMC3751826 DOI: 10.1371/journal.pone.0072924] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 07/12/2013] [Indexed: 12/12/2022] Open
Abstract
Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP) (y1) transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis.
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Affiliation(s)
- Juhyun Lee
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Mahdi Esmaily Moghadam
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
| | - Ethan Kung
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
| | - Hung Cao
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tyler Beebe
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
| | - Yury Miller
- Division of Cardiology, Department of Medicine, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Beth L. Roman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ching-Ling Lien
- Children’s Hospital Los Angeles, Los Angeles, California, United States of America
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Neil C. Chi
- Division of Cardiology, Department of Medicine, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Alison L. Marsden
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
| | - Tzung K. Hsiai
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
- Division of Cardiology, Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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41
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Bhat S, Larina IV, Larin KV, Dickinson ME, Liebling M. 4D reconstruction of the beating embryonic heart from two orthogonal sets of parallel optical coherence tomography slice-sequences. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:578-88. [PMID: 23221816 PMCID: PMC4114225 DOI: 10.1109/tmi.2012.2231692] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Current methods to build dynamic optical coherence tomography (OCT) volumes of the beating embryonic heart involve synchronization of 2D+time slice-sequences acquired over separate heartbeats. Temporal registration of these sequences is performed either through gating or postprocessing. While synchronization algorithms that exclusively rely on image- intrinsic signals allow forgoing external gating hardware, they are prone to error accumulation, require operator-supervised correction, or lead to nonisotropic resolution. Here, we propose an image-based, retrospective reconstruction technique that uses two sets of parallel 2D+T slice-sequences, acquired perpendicularly to each other, to yield accurate and automatic reconstructions with isotropic resolution. The method utilizes the similarity of the data at the slice intersections to spatio-temporally register the two sets of slice sequences and fuse them into a high-resolution 4D volume. We characterize our method by using 1) simulated heart phantom datasets and 2) OCT datasets acquired from the beating heart of live cultured E9.5 mouse and E10.5 rat embryos. We demonstrate that while our method requires greater acquisition and reconstruction time compared to methods that use slices from a single direction, it produces more accurate and self-validating reconstructions since each set of reconstructed slices acts as a reference for the slices in the perpendicular set.
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Affiliation(s)
- Sandeep Bhat
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106 USA
| | - Irina V. Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Kirill V. Larin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204 USA
| | - Mary E. Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Michael Liebling
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106 USA ()
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42
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The Transitional Cardiac Pumping Mechanics in the Embryonic Heart. Cardiovasc Eng Technol 2013; 4:246-255. [PMID: 29637499 DOI: 10.1007/s13239-013-0120-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 01/10/2013] [Indexed: 10/27/2022]
Abstract
Several studies have linked abnormal blood flow dynamics to the formation of congenital heart defects during the early stages of development. The objective of this study is to document the transition of pumping mechanics from the early tube stage to the late looping stage of the embryonic heart. The optically transparent zebrafish embryonic heart was utilized as the in vivo model and was studied using standard bright field microscopy at three relevant stages within the transitional period: (1) tube stage at 30 hours post-fertilization (hpf); (2) early cardiac looping stage at 36 hpf; and (3) late cardiac looping stage at 48 hpf. High-speed videos were collected at 1000 fps at a spatial resolution of 1.1 μm/pixel at each of these stages and were post-processed to yield blood velocity patterns as well as wall kinematics. Results show that several relevant trends exist. Morphological trends from tube through late looping include: (a) ballooning of the chambers, (b) increasing constriction at the atrioventricular junction (AVJ), and (c) repositioning of the ventricle toward the side of the atrium. Blood flow trends include: (a) higher blood velocities, (b) increased AVJ regurgitation, and (c) larger percentages of blood from the upper atrium expelled backward toward the atrial inlet. Pumping mechanics trends include: (a) increasing contraction wave delay at the AVJ, (b) the AVJ begins acting as a rudimentary valve, (c) decreasing chamber constriction during maximum contraction, and (d) a transition in ventricular kinematics from a pronounced propagating wave to an independent, full-chamber contraction. The above results provide new insight into the transitional pumping mechanics from peristalsis-like pumping to a displacement pumping mechanism.
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Abstract
This chapter examines the ways to optimize the signal-to-noise ratio while keeping the specimen healthy. Live cells expressing fluorescent protein fusions are usually dim compared to fixed specimens, both because the fluorescent proteins are not very bright and because there is, in most cases, only one fluorophores per protein. It is also favorable to choose cells that are expressing low levels of fluorescent protein fusions to minimize the difference from the levels of the endogenous protein in vivo. Long camera exposure times, which allow accumulation of weak signals, must be often avoided to reduce photobleaching and phototoxicity and to acquire images quickly enough to capture cell dynamics. Choices, such as objective lens and camera, determine the signal-to-noise ratio of an imaging system. Optimizing the imaging system to maximize signal and minimize noise is critical for live-cell fluorescence imaging. Imaging with high signal-to-noise ratio will allow detection of low concentrations of fluorescent fusion proteins with illumination conditions that are less likely to damage cells. Automation of an imaging system allows collection of multidimensional data while helping to maintain focus and minimize specimen exposure to light. Under all imaging conditions, maintaining and verifying cell health is essential to the validity of the experimental results.
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Ohn J, Tsai HJ, Liebling M. Joint dynamic imaging of morphogenesis and function in the developing heart. Organogenesis 2012; 5:248-55. [PMID: 20539745 DOI: 10.4161/org.5.4.10568] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 11/07/2009] [Accepted: 11/09/2009] [Indexed: 01/28/2023] Open
Abstract
In the developing heart, time-lapse imaging is particularly challenging. Changes in heart morphology due to tissue growth or long-term reorganization are difficult to follow because they are much subtler than the rapid shape changes induced by the heartbeat. Therefore, imaging heart development usually requires slowing or stopping the heart. This, however, leads to information loss about the unperturbed heart shape and the dynamics of heart function. To overcome this limitation, we have developed a non-invasive heart imaging technique to jointly document heart function (at fixed stages of development) as well as its morphogenesis (at any fixed phase in the heartbeat) that does not require stopping or slowing the heart. We review the challenges for imaging heart development and our methodology, which is based on computationally combining and analyzing multiple high-speed image sequences acquired throughout the course of development. We present results obtained in the developing zebrafish heart. Image analysis of the acquired data yielded blood flow velocity maps and made it possible to follow the relative movement of individual cells over several hours.
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Affiliation(s)
- Jungho Ohn
- Electrical & Computer Engineering; University of California; Santa Barbara, CA USA
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Colas JF, Sharpe J. Live optical projection tomography. Organogenesis 2012; 5:211-6. [PMID: 20539740 DOI: 10.4161/org.5.4.10426] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 09/06/2009] [Accepted: 10/26/2009] [Indexed: 01/27/2023] Open
Abstract
Optical projection tomography (OPT) is a technology ideally suited for imaging embryonic organs. We emphasize here recent successes in translating this potential into the field of live imaging. Live OPT (also known as 4D OPT, or time-lapse OPT) is already in position to accumulate good quantitative data on the developmental dynamics of organogenesis, a prerequisite for building realistic computer models and tackling new biological problems. Yet, live OPT is being further developed by merging state-of-the-art mouse embryo culture with the OPT system. We discuss the technological challenges that this entails and the prospects for expansion of this molecular imaging technique into a wider range of applications.
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Affiliation(s)
- Jean-François Colas
- EMBL-CRG Systems Biology Program; Centre for Genomic Regulation; UPF; Barcelona, Spain; Istituciô Catalana de Recerca i Estudis Avançats; Barcelona, Spain
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Larina IV, Garcia MD, Vadakkan TJ, Larin KV, Dickinson ME. Imaging mouse embryonic cardiovascular development. Cold Spring Harb Protoc 2012; 2012:1035-43. [PMID: 23028074 DOI: 10.1101/pdb.top071498] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Early development of the mammalian cardiovascular system is a highly dynamic process. Live imaging is an essential tool for analyzing normal and abnormal cardiovascular development and dynamics. This article describes two optical approaches for live dynamic imaging of mouse embryonic cardiovascular development: confocal microscopy and optical coherence tomography (OCT). Confocal microscopy, used in combination with fluorescent protein reporter lines, enables visualization of the developing and remodeling cardiovascular system with submicron resolution and even allows visualization of subcellular details of labeled structures. We describe mouse transgenic lines that can be used to image the developing vasculature and characterize hemodynamics by tracking individual blood cells. Confocal microscopy of vital fluorescent markers reveals unique details about cell morphogenesis and movement; however, the imaging depth of this method is limited to ∼200 µm. This limitation can be addressed by using OCT, which allows three-dimensional (3D) imaging millimeters into tissue, although this is achieved at the expense of lower spatial resolution (2-10 µm). We describe here how OCT can be applied to the structural analysis of developing mouse embryos and hemodynamic analysis in deep embryonic vessels. These complementary approaches can be used to analyze cardiovascular defects in mutant animals to understand genetic signaling pathways regulating human development.
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Bhat S, Ohn J, Liebling M. Motion-based structure separation for label-free, high-speed, 3D cardiac microscopy. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2012; 21:3638-3647. [PMID: 22531765 DOI: 10.1109/tip.2012.2195070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Capturing the dynamics of individual structures in the embryonic heart is an essential step for studying its function and development. Label-free brightfield (BF) microscopy allows for higher acquisition frame-rates than techniques requiring molecular labeling, without interfering with embryo viability or needing complex equipment. However, since different structures contribute similarly to image contrast, label-free microscopy lacks specificity. Here we mitigate this problem by separating a single-channel image series into multiple channels specific to different cardio-vascular structures, based only on their motion patterns. The technique combines images from multiple cardiac cycles and z-sections after non-uniform temporal registration to produce 3D+time image volumes of one full cardiac cycle with separate channels for static, transient and periodically moving structures. The resulting data is well-suited for velocity analysis and 3D-visualization. We characterize the separating capabilities of our technique on a synthetic cardiac dataset and demonstrate its practical applicability, by reconstructing three-channel views of the beating embryonic zebrafish heart with an effective frame rate of 1000 volumes (256×256×20 voxels each) per second. This technique enables quantitative characterization of dynamic heart function during cardiogenesis.
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Freund JB, Goetz JG, Hill KL, Vermot J. Fluid flows and forces in development: functions, features and biophysical principles. Development 2012; 139:1229-45. [PMID: 22395739 DOI: 10.1242/dev.073593] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Throughout morphogenesis, cells experience intracellular tensile and contractile forces on microscopic scales. Cells also experience extracellular forces, such as static forces mediated by the extracellular matrix and forces resulting from microscopic fluid flow. Although the biological ramifications of static forces have received much attention, little is known about the roles of fluid flows and forces during embryogenesis. Here, we focus on the microfluidic forces generated by cilia-driven fluid flow and heart-driven hemodynamics, as well as on the signaling pathways involved in flow sensing. We discuss recent studies that describe the functions and the biomechanical features of these fluid flows. These insights suggest that biological flow determines many aspects of cell behavior and identity through a specific set of physical stimuli and signaling pathways.
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Abstract
Due to its optical clarity and rudimentary heart structure (i.e., single atrium and ventricle), the zebrafish provides an excellent model for studying the genetic, morphological, and functional basis of normal and pathophysiological heart development in vivo. Recent advances in high-speed confocal imaging have made it possible to capture 2D zebrafish heart wall motions with temporal and spatial resolutions sufficient to characterize the highly dynamic intravital flow-structure environment. We have optimized protocols for introducing fluorescent tracer particles into the zebrafish cardiovasculature, imaging intravital heart wall motion, and performing high-resolution blood flow mapping that will be broadly useful in elucidating flow-structure relationships.
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Affiliation(s)
- Jay R Hove
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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