University of Veterinary Medicine Hannover Multimodality Molecular Imaging of Inflammation and Fibrosis in Pressure Overload-Induced Heart Failure and After Mechanical Ventricular Unloading INAUGURAL - DISSERTATION in fulfillment of the requirements of the degree of Doctor of Veterinary Medicine -Doctor medicinae veterinariae- (Dr. med. vet.) submitted by Aylina Glasenapp Kaltenkirchen Hannover 2020 Scientific supervision: Prof. Dr. med. vet. Marion Bankstahl Central Animal Facility and Institute for Laboratory Animal Science, Hannover Medical School Prof. Dr. med. Frank Michael Bengel Department of Nuclear Medicine, Hannover Medical School PD Dr. med. Katja Derlin Department of Radiology, Hannover Medical School James Thomas Thackeray, PhD Department of Nuclear Medicine, Hannover Medical School 1st supervisors: Prof. Dr. med. vet. Marion Bankstahl Prof. Dr. med. Frank Michael Bengel PD Dr. med. Katja Derlin 2nd supervisor: Prof. Dr. med. vet. Michael Fehr Clinic for Small Mammals, Reptiles and Birds, University of Veterinary Medicine Hannover Day of the oral examination: 11.05.2020 Table of Contents 1.1 Previously Published Parts of This Thesis ............................................................... V 1.2 List of Abbreviations ............................................................................................. VII 1.3 List of Figures .......................................................................................................... IX 1.4 List of Tables ............................................................................................................ X 2 Introduction ............................................................................................................... - 1 - 3 State of the Art Review ............................................................................................. - 5 - 3.1 Heart Failure ......................................................................................................... - 5 - 3.1.1 Epidemiology & Public Health Statistics ...................................................... - 5 - 3.1.2 Clinical Characterization & Classification .................................................... - 5 - 3.1.3 Pathology & Mechanisms ............................................................................. - 8 - 3.1.4 Clinical Management .................................................................................... - 9 - 3.2 Animal Models of Heart Failure and Unloading ................................................ - 10 - 3.2.1 Pharmacological Induction of Heart Failure ............................................... - 10 - 3.2.2 Surgical Induction of Heart Failure - Transverse Aortic Constriction ........ - 11 - 3.2.3 Surgical Induction of Heart Failure – Myocardial Infarction ..................... - 13 - 3.2.4 Model of Reversible Heart Failure - Reverse TAC Model ......................... - 13 - 3.2.5 Summary ..................................................................................................... - 14 - 3.3 Left Ventricular Remodeling .............................................................................. - 16 - 3.3.1 Definition .................................................................................................... - 16 - 3.3.2 Reverse Remodeling ................................................................................... - 17 - 3.3.3 Difference of TAC and MI-Induced Remodeling ....................................... - 18 - 3.4 Inflammation in Heart Failure ............................................................................ - 19 - 3.4.1 Inflammation & Pressure Overload ............................................................. - 19 - I 3.4.2 Inflammation for Prediction of Functional Outcome .................................. - 22 - 3.5 Fibrosis in Heart Failure ..................................................................................... - 23 - 3.5.1 Fibrosis & Pressure Overload ..................................................................... - 24 - 3.5.2 Fibrosis as a Therapeutic Target ................................................................. - 26 - 3.6 Imaging ............................................................................................................... - 27 - 3.6.1 Magnetic Resonance Imaging ..................................................................... - 27 - 3.6.1.1 Principle ............................................................................................... - 27 - 3.6.1.2 Clinical Relevance & Applications in Heart Failure ........................... - 28 - 3.6.1.3 T1 Mapping .......................................................................................... - 28 - 3.6.2 Positron Emission Tomography .................................................................. - 30 - 3.6.3 Principle ...................................................................................................... - 30 - 3.6.3.1 Clinical Relevance & Applications in Heart Failure ........................... - 32 - 3.6.3.2 18F-FDG & Myocardial Glucose Metabolism ...................................... - 32 - 3.6.3.3 68Ga-Pentixafor & Chemokine Receptor CXCR4 ............................... - 34 - 3.6.4 Imaging for Targeted Therapy .................................................................... - 35 - 4 Hypotheses & Objectives ........................................................................................ - 36 - 4.1 Hypotheses.......................................................................................................... - 36 - 4.2 Objectives ........................................................................................................... - 36 - 5 Experimental Design ............................................................................................... - 37 - 6 Material & Methods ................................................................................................ - 40 - 6.1 Animals ............................................................................................................... - 40 - 6.2 Surgical Models .................................................................................................. - 42 - 6.2.1 Transverse Aortic Constriction ................................................................... - 42 - 6.2.2 Reverse Transverse Aortic Constriction ..................................................... - 45 - II 6.2.3 Myocardial Infarction .................................................................................. - 45 - 6.3 Cardiac Magnetic Resonance Imaging ............................................................... - 47 - 6.3.1 Scan Protocol & Image Acquisition ............................................................ - 47 - 6.3.2 Scan Protocol ............................................................................................... - 48 - 6.3.3 Functional Cardiac Magnetic Resonance Imaging ...................................... - 50 - 6.3.4 T1 Mapping Acquisition ............................................................................. - 50 - 6.3.5 Image Analysis ............................................................................................ - 51 - 6.4 Positron Emission Tomography ......................................................................... - 53 - 6.4.1 Radiosynthesis ............................................................................................. - 53 - 6.4.2 Animal Preparation ..................................................................................... - 53 - 6.4.3 18F-FDG Scan Acquisition, Reconstruction & Analysis ............................. - 54 - 6.4.4 68Ga-Pentixafor Scan Acquisition, Reconstruction & Analysis .................. - 55 - 6.5 Ex Vivo Tissue Workup ..................................................................................... - 58 - 6.5.1 Ex Vivo Biodistribution .............................................................................. - 58 - 6.5.2 Ex Vivo Autoradiography ........................................................................... - 58 - 6.5.3 Western Immunoblotting ............................................................................. - 59 - 6.5.4 Histology ..................................................................................................... - 59 - 6.5.5 Immunohistochemistry ................................................................................ - 60 - 6.6 Analysis & Statistics ........................................................................................... - 61 - 7 Multimodality Imaging of Inflammation and Ventricular Remodeling in Pressure Overload Heart Failure ...................................................................... - 62 - 8 Multimodality Imaging of Inflammation and Fibrosis during Heart Failure Progression and Reverse Remodeling ................................................................... - 94 - 9 Discussion ............................................................................................................... - 133 - 9.1 Key Findings..................................................................................................... - 133 - III 9.2 Heart Failure Animal Models ........................................................................... - 134 - 9.3 Pathology of Inflammation ............................................................................... - 137 - 9.4 Imaging of Inflammation .................................................................................