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Updated: Dec 11, 2025
Dynamic Measurement and Imaging of Capillaries, Arterioles, and Pericytes in Mouse Heart
Published on: July 29, 2020
Dynamic Measurement and Imaging of Capillaries, Arterioles, and Pericytes in Mouse Heart
Guiling Zhao1, Humberto C Joca2, W Jonathan Lederer2
1Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine; GZhao@som.umaryland.edu.
Insights
Researchers developed a new imaging method to monitor coronary blood flow and vessel changes in mouse hearts. This technique allows detailed study of heart capillaries and arterioles, aiding research into cardiovascular diseases.
Area of Science:
- Cardiovascular Physiology
- Microcirculation Research
- Optical Imaging Techniques
Background:
- Coronary blood flow regulation is crucial for cardiomyocyte function.
- Monitoring dynamic changes in coronary arterioles and capillaries is challenging due to heart motion.
- Existing methods lack the resolution to observe microvascular dynamics in vivo.
Purpose of the Study:
- To develop and validate a novel imaging method for monitoring coronary microvascular dynamics.
- To enable simultaneous measurement of perfusion, pressure, and vessel diameter in heart capillaries and arterioles.
- To provide a platform for studying the physiological roles of pericytes and the effects of reagents on coronary blood flow.
Main Methods:
- Cannulation and perfusion of the mouse septal artery in right ventricular papillary muscle preparations.
- Intravital fluorescence imaging using labeled lectins (e.g., WGA) to visualize arterioles and capillaries.
- Measurement of vessel diameter changes during both resting and contracting states.
- Utilizing genetically encoded fluorescent proteins (e.g., NG2-DsRed) for specific cellular visualization.
Main Results:
- Successfully monitored arterial perfusion rate, pressure, and dynamic vessel diameter changes in mouse heart microvasculature.
- Enabled imaging and measurement of arterioles and capillaries in the presence and absence of heart contractions.
- Visualized specific cellular components like pericytes within the heart microvasculature.
- Demonstrated the method's suitability for assessing reagent effects on vascular diameter and pressure.
Conclusions:
- The described method provides a robust platform for studying coronary microcirculation under near-physiological conditions.
- This technique facilitates research into the function of capillary pericytes in the heart.
- It is valuable for investigating the impact of various agents on heart blood flow at the cellular and molecular level.
Abstract:
Coronary arterial tone along with the opening or closing of the capillaries largely determine the blood flow to cardiomyocytes at constant perfusion pressure. However, it is difficult to monitor the dynamic changes of the coronary arterioles and the capillaries in the whole heart, primarily due to its motion and non-stop beating. Here we describe a method that enables monitoring of arterial perfusion rate, pressure and the diameter changes of the arterioles and capillaries in mouse right ventricular papillary muscles. The mouse septal artery is cannulated and perfused at a constant flow or pressure with the other dynamically measured. After perfusion with a fluorescently labeled lectin (e.g., Alexa Fluor-488 or -633 labeled Wheat-Germ Agglutinin, WGA), the arterioles and capillaries (and other vessels) in right ventricle papillary muscle and septum could be readily imaged. The vessel-diameter changes could then be measured in the presence or absence of heart contractions. When genetically encoded fluorescent proteins were expressed, specific features could be monitored. For examples, pericytes were visualized in mouse hearts that expressed NG2-DsRed. This method has provided a useful platform to study the physiological functions of capillary pericytes in heart. It is also suitable for studying the effect of reagents on the blood flow in heart by measuring the vascular/capillary diameter and the arterial luminal pressure simultaneously. This preparation, combined with a state-of-the-art optic imaging system, allows one to study the blood flow and its control at cellular and molecular level in the heart under near-physiological conditions.
