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Updated: May 21, 2026
Non-invasive Imaging of Leukocyte Homing and Migration in vivo
Published on: December 5, 2010
Intravital 2-photon imaging of leukocyte trafficking in beating heart
Wenjun Li1, Ruben G Nava, Alejandro C Bribriesco
1Department of Surgery, Washington University School of Medicine, St. Louis, MO, USA.
Insights
Researchers developed a new method to visualize immune cell movement in beating hearts, revealing key molecular interactions that control inflammation and offering potential therapeutic targets for heart disease.
Area of Science:
- Cardiovascular Biology
- Immunology
- Microscopy
Background:
- Inflammation in heart tissue is crucial for public health.
- Understanding leukocyte recruitment in the heart is limited due to imaging challenges.
- Dynamic regulation of immune cell trafficking in the heart requires advanced visualization techniques.
Purpose of the Study:
- To develop and validate a novel intravital 2-photon microscopy method for imaging leukocyte dynamics in beating murine hearts.
- To investigate neutrophil trafficking and extravasation in the inflamed heart.
- To identify molecular targets involved in cardiac leukocyte recruitment.
Main Methods:
- Developed a technique for two-photon intravital microscopy of beating murine hearts.
- Visualized neutrophil behavior (trafficking, extravasation, infiltration) during ischemia reperfusion injury.
- Utilized genetically modified mice (mutant ICAM-1) and pharmacological blockade (Mac-1, LFA-1) to assess molecular contributions.
Main Results:
- Ischemia reperfusion injury induced neutrophil recruitment, extravasation, and myocardial infiltration, forming clusters.
- Mutant ICAM-1 impaired neutrophil crawling and extravasation.
- Inhibition of Mac-1 and LFA-1 receptors significantly reduced neutrophil adherence and extravasation in heart grafts.
Conclusions:
- The developed intravital microscopy method enables dynamic visualization of cardiac inflammation.
- ICAM-1, Mac-1, and LFA-1 play critical roles in neutrophil recruitment to the inflamed heart.
- This approach can facilitate the study of cardiac-specific leukocyte recruitment and the discovery of new therapies for heart disease.
Abstract:
Two-photon intravital microscopy has substantially broadened our understanding of tissue- and organ-specific differences in the regulation of inflammatory responses. However, little is known about the dynamic regulation of leukocyte recruitment into inflamed heart tissue, largely due to technical difficulties inherent in imaging moving tissue. Here, we report a method for imaging beating murine hearts using intravital 2-photon microscopy. Using this method, we visualized neutrophil trafficking at baseline and during inflammation. Ischemia reperfusion injury induced by transplantation or transient coronary artery ligation led to recruitment of neutrophils to the heart, their extravasation from coronary veins, and infiltration of the myocardium where they formed large clusters. Grafting hearts containing mutant ICAM-1, a ligand important for neutrophil recruitment, reduced the crawling velocities of neutrophils within vessels, and markedly inhibited their extravasation. Similar impairment was seen with the inhibition of Mac-1, a receptor for ICAM-1. Blockade of LFA-1, another ICAM-1 receptor, prevented neutrophil adherence to endothelium and extravasation in heart grafts. As inflammatory responses in the heart are of great relevance to public health, this imaging approach holds promise for studying cardiac-specific mechanisms of leukocyte recruitment and identifying novel therapeutic targets for treating heart disease.
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