Related Experiment Video
Updated: Jan 6, 2026
Quantification of Monocyte Transmigration and Foam Cell Formation from Individuals with Chronic Inflammatory Conditions
Published on: October 17, 2017
Using High-Dimensional Approaches to Probe Monocytes and Macrophages in Cardiovascular Disease
Sarah A Dick1,2, Rysa Zaman1,2, Slava Epelman1,2,3
1University Health Network, Toronto General Research Institute, Toronto, ON, Canada.
Insights
High-dimensional single-cell analysis reveals distinct cardiac macrophage populations and their role in cardiovascular inflammation. Further research is needed to understand their functional heterogeneity and origins in response to injury.
Area of Science:
- Cardiovascular Biology
- Immunology
- Cellular Heterogeneity
Background:
- Cardiovascular diseases are a leading cause of death globally.
- Monocyte-derived inflammatory processes, like atherosclerosis and myocardial infarction, involve complex myeloid cell responses.
- Understanding myeloid cell heterogeneity is crucial for addressing cardiovascular disease.
Purpose of the Study:
- To investigate the heterogeneity of myeloid cell populations in the heart.
- To understand the origins and functional roles of cardiac macrophages in cardiovascular disease.
- To explore the diversification of tissue macrophages following cardiac injury.
Main Methods:
- High-dimensional single-cell RNA sequencing.
- Functional analyses of myeloid cell populations.
- Integration of single-cell data with in vivo experimental systems.
Main Results:
- Identification of at least three distinct resident cardiac macrophage populations.
- Demonstration of significant diversification of the cardiac macrophage pool after tissue injury, driven by recruited monocytes.
- Uncovering potential distinct activation states or microenvironment-driven functions of cardiac macrophages.
Conclusions:
- High-dimensional approaches reveal significant myeloid cell heterogeneity in the heart.
- Recruited monocytes diversify into distinct macrophage populations post-injury.
- Future studies integrating in vivo systems are essential to link transcriptional heterogeneity to functional outcomes in cardiovascular inflammation.
Abstract:
High dimensional approaches that characterize single cells at unprecedented depth have helped uncover unappreciated heterogeneity, a better understanding of myeloid cell origins, developmental relationships and functions. These advancements are particularly important in cardiovascular disease, which remains the leading cause of death worldwide. Gradual, monocyte-dependent inflammatory processes, such as the development of atherosclerotic plaque within arterial vessels, contrasts with the robust acute response within the myocardium that occurs when a vessel is occluded. Monocytes and macrophages differentially contribute to tissue injury, repair and regeneration in these contexts, yet many questions remain about which myeloid cell types are involved in a coordinated, organ-level sterile inflammatory response. Single cell RNA sequencing, combined with functional analyses have demonstrated that at least three populations of resident cardiac macrophages exist, and after tissue injury, there is significant diversification of the tissue macrophage pool driven by recruited monocytes. While these studies have provided important insights, they raise many new questions and avenues for future exploration. For example, how do transcriptionally defined sub-populations of cardiac macrophages relate to each other? Are they different activation states along a pre-defined trajectory of macrophage differentiation or do local microenvironments drive newly recruited monocytes into distinct functions? The answers to these questions will require integration of high-dimensional approaches into biologically relevant in vivo experimental systems to ensure the predicted heterogeneity possess a functional outcome.
