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Bueno JM, Martínez-Ojeda RM, Pérez-Zabalza M, García-Mendívil L, Asensio MC, Ordovás L, Pueyo E. Analysis of age-related changes in the left ventricular myocardium with multiphoton microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:3251-3264. [PMID: 38855691 PMCID: PMC11161339 DOI: 10.1364/boe.509227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/27/2024] [Accepted: 03/11/2024] [Indexed: 06/11/2024]
Abstract
Aging induces cardiac remodeling, resulting in an increase in the risk of suffering heart diseases, including heart failure. Collagen deposition increases with age and, together with sarcomeric changes in cardiomyocytes, may lead to ventricular stiffness. Multiphoton (MP) microscopy is a useful technique to visualize and detect variations in cardiac structures in a label free fashion. Here, we propose a method based on MP imaging (both two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG) modalities) to explore and objectively quantify age-related structural differences in various components of cardiac tissues. Results in transmural porcine left ventricle (LV) sections reveal significant differences when comparing samples from young and old animals. Collagen and myosin SHG signals in old specimens are respectively 3.8x and >6-fold larger than in young ones. Differences in TPEF signals from cardiomyocyte were ∼3x. Moreover, the increased amount of collagen in old specimens results in a more organized pattern when compared to young LV tissues. Since changes in collagen and myosin are associated with cardiac dysfunction, the technique used herein might be a useful tool to accurately predict and measure changes associated with age-related myocardium fibrosis, tissue remodeling and sarcomeric alterations, with potential implications in preventing heart disease.
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Affiliation(s)
- Juan M. Bueno
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed. 34), 30100 Murcia, Spain
| | - Rosa M. Martínez-Ojeda
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed. 34), 30100 Murcia, Spain
| | - María Pérez-Zabalza
- BSICoS group, I3A, IIS Aragón, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Centro Universitario de la Defensa (CUD), 50018 Zaragoza, Spain
| | | | - M. Carmen Asensio
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed. 34), 30100 Murcia, Spain
| | - Laura Ordovás
- BSICoS group, I3A, IIS Aragón, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Fundación Agencia Aragonesa para la Investigación y el Desarrollo (ARAID), 50018 Zaragoza, Spain
| | - Esther Pueyo
- BSICoS group, I3A, IIS Aragón, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina, 50018 Zaragoza, Spain
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2
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So WZ, Teo RZC, Ooi LY, Goh BYS, Lu J, Vathsala A, Thamboo TP, Tiong HY. Multi-photon microscopy for the evaluation of interstitial fibrosis in extended criteria donor kidneys: A Proof-of-Concept Study. Clin Transplant 2022; 36:e14717. [PMID: 35598116 DOI: 10.1111/ctr.14717] [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: 03/03/2022] [Revised: 05/14/2022] [Accepted: 05/16/2022] [Indexed: 11/03/2022]
Abstract
INTRODUCTION To evaluate the initial use of label-free second harmonic generation (SHG) imaging with two-photon excitation (2PE) auto-fluorescence in multi-photon microscopy (MPM) for the quantification of collagen/fibrosis on pre-implantation biopsies of extended criteria donors (ECD). MATERIALS AND METHODS 20 pre-implantation core biopsies were extracted from 10 donor kidney samples, of which originated from 7 donors. Kidney Donor Profile Index (KDPI) and Remuzzi scores of biopsies were calculated. Collagen parameters measured included quantification by the Collagen Area Ratio in Total Tissue (CART) and qualitative measurements by Collagen Reticulation Index (CRI). RESULTS Biopsies classified with > 85% KDPI scores had significantly higher CART (p = 0.011) and lower CRI values (p = 0.025) than biopsies with ≤ 85% KDPI scores. Increase in CRI values correlated significantly with rise in recipient creatinine levels 1-year post-transplant (p = 0.027; 95% CI: 4.635-66.797). CONCLUSION MPM is an evolving technology that enables the quantification of the amount (CART) and quality (CRI) of collagen deposition in unstained pre-implantation biopsies of donor kidneys stratified by KDPI scores. This initial evaluation found significant differences in both parameters between donor kidneys with more or less than 85% KDPI. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wei Zheng So
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Rachel Zui Chih Teo
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore, Singapore
| | - Li Yin Ooi
- Department of Pathology, National University Hospital, Singapore, Singapore
| | - Benjamin Yen Seow Goh
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Department of Urology, National University Hospital, Singapore, Singapore.,National University Centre for Organ Transplantation, National University Hospital, Singapore, Singapore
| | - Jirong Lu
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Department of Urology, National University Hospital, Singapore, Singapore.,National University Centre for Organ Transplantation, National University Hospital, Singapore, Singapore
| | - Anantharaman Vathsala
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Division of Nephrology, Department of Medicine, National University Hospital, Singapore, Singapore.,National University Centre for Organ Transplantation, National University Hospital, Singapore, Singapore
| | - Thomas Paulraj Thamboo
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Division of Nephrology, Department of Medicine, National University Hospital, Singapore, Singapore
| | - Ho Yee Tiong
- Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Department of Urology, National University Hospital, Singapore, Singapore.,National University Centre for Organ Transplantation, National University Hospital, Singapore, Singapore
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Assessment of Ultra-Early-Stage Liver Fibrosis in Human Non-Alcoholic Fatty Liver Disease by Second-Harmonic Generation Microscopy. Int J Mol Sci 2022; 23:ijms23063357. [PMID: 35328778 PMCID: PMC8949080 DOI: 10.3390/ijms23063357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 12/10/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is associated with the chronic progression of fibrosis. In general, the progression of liver fibrosis is determined by a histopathological assessment with a collagen-stained section; however, the ultra-early stage of liver fibrosis is challenging to identify because of the low sensitivity in the collagen-selective staining method. In the present study, we demonstrate the feasibility of second-harmonic generation (SHG) microscopy in the histopathological diagnosis of the liver of NAFLD patients for the quantitative assessment of the ultra-early stage of fibrosis. We investigated four representative NAFLD patients with early stages of fibrosis. SHG microscopy visualised well-matured fibrotic structures and early fibrosis diffusely involving liver tissues, whereas early fibrosis is challenging to be identified by conventional histopathological methods. Furthermore, the SHG emission directionality analysis revealed the maturation of each collagen fibre of each patient. As a result, SHG microscopy is feasible for assessing liver fibrosis on NAFLD patients, including the ultra-early stage of liver fibrosis that is difficult to diagnose by the conventional histopathological method. The assessment method of the ultra-early fibrosis by using SHG microscopy may serve as a crucial means for pathological, clinical, and prognostic diagnosis of NAFLD patients.
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Müllenbroich MC, Kelly A, Acker C, Bub G, Bruegmann T, Di Bona A, Entcheva E, Ferrantini C, Kohl P, Lehnart SE, Mongillo M, Parmeggiani C, Richter C, Sasse P, Zaglia T, Sacconi L, Smith GL. Novel Optics-Based Approaches for Cardiac Electrophysiology: A Review. Front Physiol 2021; 12:769586. [PMID: 34867476 PMCID: PMC8637189 DOI: 10.3389/fphys.2021.769586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/18/2021] [Indexed: 12/31/2022] Open
Abstract
Optical techniques for recording and manipulating cellular electrophysiology have advanced rapidly in just a few decades. These developments allow for the analysis of cardiac cellular dynamics at multiple scales while largely overcoming the drawbacks associated with the use of electrodes. The recent advent of optogenetics opens up new possibilities for regional and tissue-level electrophysiological control and hold promise for future novel clinical applications. This article, which emerged from the international NOTICE workshop in 2018, reviews the state-of-the-art optical techniques used for cardiac electrophysiological research and the underlying biophysics. The design and performance of optical reporters and optogenetic actuators are reviewed along with limitations of current probes. The physics of light interaction with cardiac tissue is detailed and associated challenges with the use of optical sensors and actuators are presented. Case studies include the use of fluorescence recovery after photobleaching and super-resolution microscopy to explore the micro-structure of cardiac cells and a review of two photon and light sheet technologies applied to cardiac tissue. The emergence of cardiac optogenetics is reviewed and the current work exploring the potential clinical use of optogenetics is also described. Approaches which combine optogenetic manipulation and optical voltage measurement are discussed, in terms of platforms that allow real-time manipulation of whole heart electrophysiology in open and closed-loop systems to study optimal ways to terminate spiral arrhythmias. The design and operation of optics-based approaches that allow high-throughput cardiac electrophysiological assays is presented. Finally, emerging techniques of photo-acoustic imaging and stress sensors are described along with strategies for future development and establishment of these techniques in mainstream electrophysiological research.
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Affiliation(s)
| | - Allen Kelly
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Corey Acker
- Center for Cell Analysis and Modeling, UConn Health, Farmington, CT, United States
| | - Gil Bub
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Tobias Bruegmann
- Institute for Cardiovascular Physiology, University Medical Center Goettingen, Goettingen, Germany
| | - Anna Di Bona
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy
| | - Emilia Entcheva
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | | | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Stephan E. Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, Göttingen, Germany
- Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | | | - Claudia Richter
- German Primate Center - Leibniz Institute for Primate Research, Göttingen, Germany
| | - Philipp Sasse
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Leonardo Sacconi
- European Laboratory for Nonlinear Spectroscopy, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- National Institute of Optics, National Research Council, Florence, Italy
| | - Godfrey L. Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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Jannasch A, Schnabel C, Galli R, Faak S, Büttner P, Dittfeld C, Tugtekin SM, Koch E, Matschke K. Optical coherence tomography and multiphoton microscopy offer new options for the quantification of fibrotic aortic valve disease in ApoE -/- mice. Sci Rep 2021; 11:5834. [PMID: 33712671 PMCID: PMC7955095 DOI: 10.1038/s41598-021-85142-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/25/2021] [Indexed: 01/31/2023] Open
Abstract
Aortic valve sclerosis is characterized as the thickening of the aortic valve without obstruction of the left ventricular outflow. It has a prevalence of 30% in people over 65 years old. Aortic valve sclerosis represents a cardiovascular risk marker because it may progress to moderate or severe aortic valve stenosis. Thus, the early recognition and management of aortic valve sclerosis are of cardinal importance. We examined the aortic valve geometry and structure from healthy C57Bl6 wild type and age-matched hyperlipidemic ApoE-/- mice with aortic valve sclerosis using optical coherence tomography (OCT) and multiphoton microscopy (MPM) and compared results with histological analyses. Early fibrotic thickening, especially in the tip region of the native aortic valve leaflets from the ApoE-/- mice, was detectable in a precise spatial resolution using OCT. Evaluation of the second harmonic generation signal using MPM demonstrated that collagen content decreased in all aortic valve leaflet regions in the ApoE-/- mice. Lipid droplets and cholesterol crystals were detected using coherent anti-Stokes Raman scattering in the tissue from the ApoE-/- mice. Here, we demonstrated that OCT and MPM, which are fast and precise contactless imaging approaches, are suitable for defining early morphological and structural alterations of sclerotic murine aortic valves.
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Affiliation(s)
- Anett Jannasch
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstraße 76, 01307, Dresden, Germany.
| | - Christian Schnabel
- Department of Anesthesiology and Intensive Care Medicine and Clinical Sensoring and Monitoring, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Roberta Galli
- Department of Anesthesiology and Intensive Care Medicine and Clinical Sensoring and Monitoring, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Saskia Faak
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstraße 76, 01307, Dresden, Germany
| | - Petra Büttner
- Department of Cardiology, Heart Center Leipzig At University Leipzig, Leipzig, Germany
| | - Claudia Dittfeld
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstraße 76, 01307, Dresden, Germany
| | - Sems Malte Tugtekin
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstraße 76, 01307, Dresden, Germany
| | - Edmund Koch
- Department of Anesthesiology and Intensive Care Medicine and Clinical Sensoring and Monitoring, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Klaus Matschke
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, Fetscherstraße 76, 01307, Dresden, Germany
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6
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Travers JG, Wennersten SA, Peña B, Bagchi RA, Smith HE, Hirsch RA, Vanderlinden LA, Lin YH, Dobrinskikh E, Demos-Davies KM, Cavasin MA, Mestroni L, Steinkühler C, Lin CY, Houser SR, Woulfe KC, Lam MPY, McKinsey TA. HDAC Inhibition Reverses Preexisting Diastolic Dysfunction and Blocks Covert Extracellular Matrix Remodeling. Circulation 2021; 143:1874-1890. [PMID: 33682427 DOI: 10.1161/circulationaha.120.046462] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Diastolic dysfunction (DD) is associated with the development of heart failure and contributes to the pathogenesis of other cardiac maladies, including atrial fibrillation. Inhibition of histone deacetylases (HDACs) has been shown to prevent DD by enhancing myofibril relaxation. We addressed the therapeutic potential of HDAC inhibition in a model of established DD with preserved ejection fraction. METHODS Four weeks after uninephrectomy and implantation with deoxycorticosterone acetate pellets, when DD was clearly evident, 1 cohort of mice was administered the clinical-stage HDAC inhibitor ITF2357/Givinostat. Echocardiography, blood pressure measurements, and end point invasive hemodynamic analyses were performed. Myofibril mechanics and intact cardiomyocyte relaxation were assessed ex vivo. Cardiac fibrosis was evaluated by picrosirius red staining and second harmonic generation microscopy of left ventricle (LV) sections, RNA sequencing of LV mRNA, mass spectrometry-based evaluation of decellularized LV biopsies, and atomic force microscopy determination of LV stiffness. Mechanistic studies were performed with primary rat and human cardiac fibroblasts. RESULTS HDAC inhibition normalized DD without lowering blood pressure in this model of systemic hypertension. In contrast to previous models, myofibril relaxation was unimpaired in uninephrectomy/deoxycorticosterone acetate mice. Furthermore, cardiac fibrosis was not evident in any mouse cohort on the basis of picrosirius red staining or second harmonic generation microscopy. However, mass spectrometry revealed induction in the expression of >100 extracellular matrix proteins in LVs of uninephrectomy/deoxycorticosterone acetate mice, which correlated with profound tissue stiffening based on atomic force microscopy. ITF2357/Givinostat treatment blocked extracellular matrix expansion and LV stiffening. The HDAC inhibitor was subsequently shown to suppress cardiac fibroblast activation, at least in part, by blunting recruitment of the profibrotic chromatin reader protein BRD4 (bromodomain-containing protein 4) to key gene regulatory elements. CONCLUSIONS These findings demonstrate the potential of HDAC inhibition as a therapeutic intervention to reverse existing DD and establish blockade of extracellular matrix remodeling as a second mechanism by which HDAC inhibitors improve ventricular filling. Our data reveal the existence of pathophysiologically relevant covert or hidden cardiac fibrosis that is below the limit of detection of histochemical stains such as picrosirius red, highlighting the need to evaluate fibrosis of the heart using diverse methodologies.
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Affiliation(s)
- Joshua G Travers
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Sara A Wennersten
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Brisa Peña
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Rushita A Bagchi
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Harrison E Smith
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.).,Department of Biostatistics and Informatics (H.E.S., L.A.V.), Colorado School of Public Health, Aurora
| | - Rachel A Hirsch
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.)
| | - Lauren A Vanderlinden
- Department of Biostatistics and Informatics (H.E.S., L.A.V.), Colorado School of Public Health, Aurora
| | - Ying-Hsi Lin
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Evgenia Dobrinskikh
- Department of Medicine, Division of Pulmonary Sciences & Critical Care (E.D.), University of Colorado Anschutz Medical Campus, Aurora
| | - Kimberly M Demos-Davies
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Maria A Cavasin
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Luisa Mestroni
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | | | - Charles Y Lin
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.).,now with Kronos Bio, Cambridge, MA (C.Y.L.)
| | - Steven R Houser
- Cardiovascular Research Center (S.R.H.), Lewis Katz School of Medicine, Temple University, Philadelphia, PA
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Maggie P Y Lam
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Timothy A McKinsey
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
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7
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Sahu SP, Liu Q, Prasad A, Hasan SMA, Liu Q, Rodriguez MXB, Mukhopadhyay O, Burk D, Francis J, Mukhopadhyay S, Fu X, Gartia MR. Characterization of fibrillar collagen isoforms in infarcted mouse hearts using second harmonic generation imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:604-618. [PMID: 33520391 PMCID: PMC7818962 DOI: 10.1364/boe.410347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
We utilized collagen specific second harmonic generation (SHG) signatures coupled with correlative immunofluorescence imaging techniques to characterize collagen structural isoforms (type I and type III) in a murine model of myocardial infarction (MI). Tissue samples were imaged over a four week period using SHG, transmitted light microscopy and immunofluorescence imaging using fluorescently-labeled collagen antibodies. The post-mortem cardiac tissue imaging using SHG demonstrated a progressive increase in collagen deposition in the left ventricle (LV) post-MI. We were able to monitor structural morphology and LV remodeling parameters in terms of extent of LV dilation, stiffness and fiber dimensions in the infarcted myocardium.
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Affiliation(s)
- Sushant P Sahu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Qianglin Liu
- LSU AgCenter, School of Animal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Alisha Prasad
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Syed Mohammad Abid Hasan
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Qun Liu
- Department of Computer Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | | | | | - David Burk
- Shared Instrumentation Facility and Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Joseph Francis
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Supratik Mukhopadhyay
- Department of Computer Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Xing Fu
- LSU AgCenter, School of Animal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Manas Ranjan Gartia
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
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8
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Nicolas JD, Khan A, Markus A, Mohamed BA, Toischer K, Alves F, Salditt T. X-ray diffraction and second harmonic imaging reveal new insights into structural alterations caused by pressure-overload in murine hearts. Sci Rep 2020; 10:19317. [PMID: 33168890 PMCID: PMC7653033 DOI: 10.1038/s41598-020-76163-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/13/2020] [Indexed: 12/28/2022] Open
Abstract
We demonstrate a label-free imaging approach to study cardiac remodeling of fibrotic and hypertrophic hearts, bridging scales from the whole organ down to the molecular level. To this end, we have used mice subjected to transverse aortic constriction and imaged adjacent cardiac tissue sections by microfocus X-ray diffraction and second harmonic generation (SHG) imaging. In this way, the acto-myosin structure was probed in a spatially resolved manner for entire heart sections. From the recorded diffraction data, spatial maps of diffraction intensity, anisotropy and orientation were obtained, and fully automated analysis depicted the acto-myosin filament spacing and direction. X-ray diffraction presented an overview of entire heart sections and revealed that in regions of severe cardiac remodeling the muscle mass is partly replaced by connective tissue and the acto-myosin lattice spacing is increased at these regions. SHG imaging revealed sub-cellular structure of cardiac tissue and complemented the findings from X-ray diffraction by revealing micro-level distortion of myofibrils, immune cell infiltration at regions of cardiac remodeling and the development of fibrosis down to the scale of a single collagen fibril. Overall, our results show that both X-ray diffraction and SHG imaging can be used for label-free and high-resolution visualization of cardiac remodeling and fibrosis progression at different stages in a cardiac pressure-overload mouse model that cannot be achieved by conventional histology.
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Affiliation(s)
- Jan-David Nicolas
- Institute for X-Ray Physics, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Amara Khan
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Andrea Markus
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Belal A Mohamed
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, 37075, Göttingen, Germany
| | - Karl Toischer
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, 37075, Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
- Clinic for Hematology and Medical Oncology, Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
| | - Tim Salditt
- Institute for X-Ray Physics, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells", University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
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9
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Hendon CP, Lye TH, Yao X, Gan Y, Marboe CC. Optical coherence tomography imaging of cardiac substrates. Quant Imaging Med Surg 2019; 9:882-904. [PMID: 31281782 DOI: 10.21037/qims.2019.05.09] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cardiovascular disease is the leading cause of morbidity and mortality in the United States. Knowledge of a patient's heart structure will help to plan procedures, potentially identifying arrhythmia substrates, critical structures to avoid, detect transplant rejection, and reduce ambiguity when interpreting electrograms and functional measurements. Similarly, basic research of numerous cardiac diseases would greatly benefit from structural imaging at cellular scale. For both applications imaging on the scale of a myocyte is needed, which is approximately 100 µm × 10 µm. The use of optical coherence tomography (OCT) as a tool for characterizing cardiac tissue structure and function has been growing in the past two decades. We briefly review OCT principles and highlight important considerations when imaging cardiac muscle. In particular, image penetration, tissue birefringence, and light absorption by blood during in vivo imaging are important factors when imaging the heart with OCT. Within the article, we highlight applications of cardiac OCT imaging including imaging heart tissue structure in small animal models, quantification of myofiber organization, monitoring of radiofrequency ablation (RFA) lesion formation, structure-function analysis enabled by functional extensions of OCT and multimodal analysis and characterizing important substrates within the human heart. The review concludes with a summary and future outlook of OCT imaging the heart, which is promising with progress in optical catheter development, functional extensions of OCT, and real time image processing to enable dynamic imaging and real time tracking during therapeutic procedures.
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Affiliation(s)
| | | | | | - Yu Gan
- Columbia University, New York, NY, USA
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10
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Yao X, Gan Y, Ling Y, Marboe CC, Hendon CP. Multicontrast endomyocardial imaging by single-channel high-resolution cross-polarization optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:e201700204. [PMID: 29165902 PMCID: PMC6186148 DOI: 10.1002/jbio.201700204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/19/2017] [Accepted: 11/20/2017] [Indexed: 05/10/2023]
Abstract
A single-channel high-resolution cross-polarization (CP) optical coherence tomography (OCT) system is presented for multicontrast imaging of human myocardium in one-shot measurement. The intensity and functional contrasts, including the ratio between the cross- and co-polarization channels as well as the cumulative retardation, are reconstructed from the CP-OCT readout. By comparing the CP-OCT results with histological analysis, it is shown that the system can successfully delineate microstructures in the myocardium and differentiate the fibrotic myocardium from normal or ablated myocardium based on the functional contrasts provided by the CP-OCT system. The feasibility of using A-line profiles from the 2 orthogonal polarization channels to identify fibrotic myocardium, normal myocardium and ablated lesion is also discussed.
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Affiliation(s)
- Xinwen Yao
- Department of Electrical Engineering, Columbia University, New York, New York
| | - Yu Gan
- Department of Electrical Engineering, Columbia University, New York, New York
| | - Yuye Ling
- Department of Electrical Engineering, Columbia University, New York, New York
| | - Charles C. Marboe
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York
| | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, New York, New York
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11
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Holmes JW, Wagenseil JE. Special Issue: Spotlight of the Future of Cardiovascular Engineering Frontiers and Challenges in Cardiovascular Biomechanics. J Biomech Eng 2016; 138:2565870. [PMID: 27701627 DOI: 10.1115/1.4034873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Jeffrey W Holmes
- Departments of Biomedical Engineering and Medicine and Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
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12
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Ranjit S, Dvornikov A, Levi M, Furgeson S, Gratton E. Characterizing fibrosis in UUO mice model using multiparametric analysis of phasor distribution from FLIM images. BIOMEDICAL OPTICS EXPRESS 2016; 7:3519-3530. [PMID: 27699117 PMCID: PMC5030029 DOI: 10.1364/boe.7.003519] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/09/2016] [Accepted: 08/12/2016] [Indexed: 05/22/2023]
Abstract
Phasor approach to fluorescence lifetime microscopy is used to study development of fibrosis in the unilateral ureteral obstruction model (UUO) of kidney in mice. Traditional phasor analysis has been modified to create a multiparametric analysis scheme that splits the phasor points in four equidistance segments based on the height of peak of the phasor distribution and calculates six parameters including average phasor positions, the shape of each segment, the angle of the distribution and the number of points in each segment. These parameters are used to create a spectrum of twenty four points specific to the phasor distribution of each sample. Comparisons of spectra from diseased and healthy tissues result in quantitative separation and calculation of statistical parameters including AUC values, positive prediction values and sensitivity. This is a new method in the evolving field of analyzing phasor distribution of FLIM data and provides further insights. Additionally, the progression of fibrosis with time is detected using this multiparametric approach to phasor analysis.
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Affiliation(s)
- Suman Ranjit
- Laboratory Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Alexander Dvornikov
- Laboratory Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Moshe Levi
- Departments of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, Colorado, USA
| | - Seth Furgeson
- Departments of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, Colorado, USA
| | - Enrico Gratton
- Laboratory Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA
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13
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Qian HS, Weldon SM, Matera D, Lee C, Yang H, Fryer RM, Fogo AB, Reinhart GA. Quantification and Comparison of Anti-Fibrotic Therapies by Polarized SRM and SHG-Based Morphometry in Rat UUO Model. PLoS One 2016; 11:e0156734. [PMID: 27257917 PMCID: PMC4892485 DOI: 10.1371/journal.pone.0156734] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 05/18/2016] [Indexed: 12/20/2022] Open
Abstract
Renal interstitial fibrosis (IF) is an important pathologic manifestation of disease progression in a variety of chronic kidney diseases (CKD). However, the quantitative and reproducible analysis of IF remains a challenge, especially in experimental animal models of progressive IF. In this study, we compare traditional polarized Sirius Red morphometry (SRM) to novel Second Harmonic Generation (SHG)-based morphometry of unstained tissues for quantitative analysis of IF in the rat 5 day unilateral ureteral obstruction (UUO) model. To validate the specificity of SHG for detecting fibrillar collagen components in IF, co-localization studies for collagens type I, III, and IV were performed using IHC. In addition, we examined the correlation, dynamic range, sensitivity, and ability of polarized SRM and SHG-based morphometry to detect an anti-fibrotic effect of three different treatment regimens. Comparisons were made across three separate studies in which animals were treated with three mechanistically distinct pharmacologic agents: enalapril (ENA, 15, 30, 60 mg/kg), mycophenolate mofetil (MMF, 2, 20 mg/kg) or the connective tissue growth factor (CTGF) neutralizing antibody, EX75606 (1, 3, 10 mg/kg). Our results demonstrate a strong co-localization of the SHG signal with fibrillar collagens I and III but not non-fibrillar collagen IV. Quantitative IF, calculated as percent cortical area of fibrosis, demonstrated similar response profile for both polarized SRM and SHG-based morphometry. The two methodologies exhibited a strong correlation across all three pharmacology studies (r2 = 0.89–0.96). However, compared with polarized SRM, SHG-based morphometry delivered a greater dynamic range and absolute magnitude of reduction of IF after treatment. In summary, we demonstrate that SHG-based morphometry in unstained kidney tissues is comparable to polarized SRM for quantitation of fibrillar collagens, but with an enhanced sensitivity to detect treatment-induced reductions in IF. Thus, performing SHG-based morphometry on unstained kidney tissue is a reliable alternative to traditional polarized SRM for quantitative analysis of IF.
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Affiliation(s)
- Hu Sheng Qian
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
- * E-mail:
| | - Steve M. Weldon
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
| | - Damian Matera
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
| | - ChungWein Lee
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
| | - Haichun Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Ryan M. Fryer
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
| | - Agnes B. Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Glenn A. Reinhart
- CardioMetabolic Disease Research, Boehringer Ingelheim Pharmaceutics, Inc, Ridgefield, Connecticut, United States of America
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14
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Jensen T, Holten-Rossing H, Svendsen IMH, Jacobsen C, Vainer B. Quantitative analysis of myocardial tissue with digital autofluorescence microscopy. J Pathol Inform 2016; 7:15. [PMID: 27141321 PMCID: PMC4837794 DOI: 10.4103/2153-3539.179908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 02/23/2016] [Indexed: 01/04/2023] Open
Abstract
Background: The opportunity offered by whole slide scanners of automated histological analysis implies an ever increasing importance of digital pathology. To go beyond the importance of conventional pathology, however, digital pathology may need a basic histological starting point similar to that of hematoxylin and eosin staining in conventional pathology. This study presents an automated fluorescence-based microscopy approach providing highly detailed morphological data from unstained microsections. This data may provide a basic histological starting point from which further digital analysis including staining may benefit. Methods: This study explores the inherent tissue fluorescence, also known as autofluorescence, as a mean to quantitate cardiac tissue components in histological microsections. Data acquisition using a commercially available whole slide scanner and an image-based quantitation algorithm are presented. Results: It is shown that the autofluorescence intensity of unstained microsections at two different wavelengths is a suitable starting point for automated digital analysis of myocytes, fibrous tissue, lipofuscin, and the extracellular compartment. The output of the method is absolute quantitation along with accurate outlines of above-mentioned components. The digital quantitations are verified by comparison to point grid quantitations performed on the microsections after Van Gieson staining. Conclusion: The presented method is amply described as a prestain multicomponent quantitation and outlining tool for histological sections of cardiac tissue. The main perspective is the opportunity for combination with digital analysis of stained microsections, for which the method may provide an accurate digital framework.
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Affiliation(s)
- Thomas Jensen
- Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Holten-Rossing
- Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ida M H Svendsen
- Department of Forensic Pathology, University of Copenhagen, Copenhagen, Denmark
| | - Christina Jacobsen
- Department of Forensic Pathology, University of Copenhagen, Copenhagen, Denmark
| | - Ben Vainer
- Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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15
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Masè M, Cristoforetti A, Avogaro L, Tessarolo F, Piccoli F, Caola I, Pederzolli C, Graffigna A, Ravelli F. A spectral approach for the quantitative description of cardiac collagen network from nonlinear optical imaging. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:6257-60. [PMID: 26737722 DOI: 10.1109/embc.2015.7319822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The assessment of collagen structure in cardiac pathology, such as atrial fibrillation (AF), is essential for a complete understanding of the disease. This paper introduces a novel methodology for the quantitative description of collagen network properties, based on the combination of nonlinear optical microscopy with a spectral approach of image processing and analysis. Second-harmonic generation (SHG) microscopy was applied to atrial tissue samples from cardiac surgery patients, providing label-free, selective visualization of the collagen structure. The spectral analysis framework, based on 2D-FFT, was applied to the SHG images, yielding a multiparametric description of collagen fiber orientation (angle and anisotropy indexes) and texture scale (dominant wavelength and peak dispersion indexes). The proof-of-concept application of the methodology showed the capability of our approach to detect and quantify differences in the structural properties of the collagen network in AF versus sinus rhythm patients. These results suggest the potential of our approach in the assessment of collagen properties in cardiac pathologies related to a fibrotic structural component.
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16
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Sikora M, Scheiner D, Betschart C, Perucchini D, Mateos JM, di Natale A, Fink D, Maake C. Label-free, three-dimensional multiphoton microscopy of the connective tissue in the anterior vaginal wall. Int Urogynecol J 2014; 26:685-91. [PMID: 25421935 DOI: 10.1007/s00192-014-2571-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/04/2014] [Indexed: 11/27/2022]
Abstract
INTRODUCTION AND HYPOTHESIS Multiphoton microscopy (MPM) is a nonlinear, high-resolution laser scanning technique and a powerful approach for analyzing the spatial architecture within tissues. To demonstrate the potential of this technique for studying the extracellular matrix of the pelvic organs, we aimed to establish protocols for the detection of collagen and elastin in the vagina and to compare the MPM density of these fibers to fibers detected using standard histological methods. METHODS Samples of the anterior vaginal wall were obtained from nine patients undergoing a hysterectomy or cystocele repair. Samples were shock frozen, fixed with formaldehyde or Thiel's solution, or left untreated. Samples were imaged with MPM to quantify the amount of collagen and elastin via second harmonic generation and autofluorescence, respectively. In six patients, sample sections were also histologically stained and imaged with brightfield microscopy. The density of the fibers was quantified using the StereoInvestigator and Cavalieri software. RESULTS With MPM, collagen and elastin could be visualized to a depth of 100 μm, and no overlap of signals was detected. The different tissue processing protocols used did not result in significantly different fiber counts after MPM. MPM-based fiber quantifications are comparable to those based on conventional histological stains. However, MPM provided superior resolution, particularly of collagen fibers. CONCLUSIONS MPM is a robust, rapid, and label-free method that can be used to quantify the collagen and elastin content in thick specimens of the vagina. It is an excellent tool for future three-dimensional studies of the extracellular matrix in patients with pelvic organ prolapse.
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Affiliation(s)
- Michal Sikora
- Department of Gynecology, University Hospital Zurich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland,
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17
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Wang Z, Qin W, Shao Y, Ma S, Borg TK, Gao BZ. Pulse splitter-based nonlinear microscopy for live-cardiomyocyte imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 8948. [PMID: 25767692 DOI: 10.1117/12.2041845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Second harmonic generation (SHG) microscopy is a new imaging technique used in sarcomeric-addition studies. However, during the early stage of cell culture in which sarcomeric additions occur, the neonatal cardiomyocytes that we have been working with are very sensitive to photodamage, the resulting high rate of cell death prevents systematic study of sarcomeric addition using a conventional SHG system. To address this challenge, we introduced use of the pulse-splitter system developed by Na Ji et al. in our two photon excitation fluorescence (TPEF) and SHG hybrid microscope. The system dramatically reduced photodamage to neonatal cardiomyocytes in early stages of culture, greatly increasing cell viability. Thus continuous imaging of live cardiomyocytes was achieved with a stronger laser and for a longer period than has been reported in the literature. The pulse splitter-based TPEF-SHG microscope constructed in this study was demonstrated to be an ideal imaging system for sarcomeric addition-related investigations of neonatal cardiomyocytes in early stages of culture.
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Affiliation(s)
- Zhonghai Wang
- Department of Bioengineering, COMSET, Clemson University, Clemson, SC 29631, USA
| | - Wan Qin
- Department of Bioengineering, COMSET, Clemson University, Clemson, SC 29631, USA
| | - Yonghong Shao
- Institute of Optoelectronics, Shenzhen University, Shenzhen, Guangdong 518060, PR China
| | - Siyu Ma
- Department of Bioengineering, COMSET, Clemson University, Clemson, SC 29631, USA
| | - Thomas K Borg
- Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Bruce Z Gao
- Department of Bioengineering, COMSET, Clemson University, Clemson, SC 29631, USA
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