Revealing Subtle Changes in Cardiac Function using Transthoracic Dobutamine Stress Echocardiography in Mice

Summary

Left ventricular dysfunction constitutes the final common pathway for a host of cardiac disorders. We here provide a detailed protocol of transthoracic dobutamine stress echocardiography approach for comprehensive evaluation of the left ventricular function of mouse models of cardiac disease as well as cardiac phenotyping.

Abstract

Left ventricular (LV) dysfunction paves the final pathway for a multitude of cardiac disorders. With the non-invasive high-frequency transthoracic dobutamine stress echocardiography in humans, a reductionist investigation approach to unmask subtle changes in cardiac function has become possible. Here, we provide a protocol for using this technique in mice to facilitate expanded analysis of LV architecture and function in physiology and pathology enabling the observation of alterations in models of cardiac disease hidden in unstressed hearts. This investigation can be performed in one and the same animal and allows both, basal and pharmacologically stress-induced measurements. We outline detailed criteria for appropriate anesthesia, imaging-based LV analysis, consideration of intra- and interobserver variability, and obtaining positive inotrope response that can be attained in mice after intraperitoneal injection of dobutamine under near physiological conditions. To recapitulate the characteristics of human physiology and disease in small animal models, we highlight critical pitfalls in evaluation, e.g., a pronounced Bowditch effect in mice. To further meet translational objectives, we compare stress-induced effects in humans and mice. When used in translational studies, attention must be paid to physiological differences between mice and human. Experimental rigor dictates that some parameters assessed in patients can only be used with caution due to restrictions in spatial and temporal resolution in mouse models.

Introduction

The hallmark of many cardiac diseases in human is a systolic and/or diastolic functional impairment of the left ventricle (LV). For the detection of structural abnormalities, the diagnosis, and the management of systolic heart failure as well as the evaluation of diastolic function in patients with symptoms of heart failure, echocardiography is used as a fundamental assessment modality.

Since the symptoms are unspecific and more than one third of patients with the clinical syndrome of heart failure may not suffer from the actual heart failure, it is important to find an objective echocardiographic correlate for the pat....

Protocol

All methods and procedures were performed in accordance and compliance with all relevant regulations ('European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes' (Directive 2010/63/EU) and animal care was in accordance with institutional guidelines. Data from human subjects were analyzed in compliance with all institutional, national, and international guidelines for human welfare and was approved by the Local Ethics Committee (20-9218-BO). All experiments ha.......

Discussion

Stress-induced evaluation of the cardiac function is widely used in humans in a clinical setting using exercise testing or pharmacological stress testing^6,7. Because immediate post-exercise echocardiography of mice is very limited due to the need for sedation, dobutamine-induced stress echocardiography is likely to be the most translational method to assess stress-induced cardiac physiopathology. Reliable information on cardiac function can be obtained using real.......

Materials

Name	Company	Catalog Number	Comments
Activated Charcoal Filter	UNO BV	180000140	http://www.unobv.com/Rest%20Gas%20Filters.html
Aquasonic 100 Ultrasound Transmission Gel	Parker Laboratories	001-02	https://www.parkerlabs.com/aquasonic-100.asp
Chemical Hair removal lotion	General Supply	-
Cotton Swaps	General Supply	-
ddH2O	General Supply	-
Dobutamine	Carinopharm	71685.00.00	https://www.carinopharm.de/stammsortiment/#103
Flowmeter for laboratory animal anesthesia	UNO BV	SF3	http://www.unobv.com/Flowmeters.html
Gas Exhaust Unit	UNO BV	-	http://www.unobv.com/Gas%20Exhaust%20Unit.html
Heating Lamp	Philips	-
Induction Box	UNO BV	-	http://www.unobv.com/Induction%20box.html
Medical Sharps Container	BD	305626	https://legacy.bd.com/europe/safety/de/products/sharps/
MX400 ultrasound transducer (20-46 Mhz)	VisualSonics	MX400	https://www.visualsonics.com/product/transducers/mx-series-transducers
Octenisept disinfectant	Schuelke	173711	https://www.schuelke.com/de-de/produkte/octenisept.php
Omnican F syringe with needle 1ml	B. Braun	9161502S	https://www.bbraun.de/de/products/b60/omnican-f.html
Paper Towels	General Supply	-
Signacreme Electrode Cream	Parker Laboratories	017-05	https://www.parkerlabs.com/Signacreme.asp
Standard Gauze Pads	BeeSana Meditrade	4852728	https://www.meditrade.de/de/wundversorgung/verbandstoffe/beesana-mullkompresse/
Thermasonic Gel Warmer	Parker Laboratories	82-03-20 CE	https://www.parkerlabs.com/thermasonic_apta_sbp.asp
Transpore Tape	3M	1527NP-0	https://www.3mdeutschland.de/3M/de_DE/unternehmen-de/produkte/~/3M-Transpore-Fixierpflaster/
Vaporizer Sigma Delta	UNO BV	-	http://www.unobv.com/Vaporizers.html
Vevo 3100 high-frequency preclinical ultrasound imaging system	VisualSonics	Vevo3100	https://www.visualsonics.com/product/imaging-systems/vevo-3100 * required software package: Cardiovascular package; B-mode, M-mode, pulsed-wave doppler mode
Vevo Imaging Station with integrated rail system, heated platform and physiological monitoring unit	VisualSonics	-	https://www.visualsonics.com/product/accessories/imaging-stations
VevoLab Analysis Software	VisualSonics	Vers. 3.2.5	https://www.visualsonics.com/product/software/vevo-lab *required software package: Vevo Strain, LV analysis