Molecular Imaging of Inflammation in Ischemic Heart Disease

Molecular and Nonmolecular Imaging of Macrophages in Atherosclerosis

Atherosclerosis is a major cause of ischemic heart disease, and the increasing medical burden associated with atherosclerotic cardiovascular disease has become a major public health concern worldwide. Macrophages play an important role in all stages of the dynamic progress of atherosclerosis, from its initiation and lesion expansion increasing the vulnerability of plaques, to the formation of unstable plaques and clinical manifestations. Early imaging can identify patients at risk of coronary atherosclerotic disease and its complications, enabling preventive measures to be initiated. Recent advances in molecular imaging have involved the noninvasive and semi-quantitative targeted imaging of macrophages and their related molecules in vivo, which can detect atheroma earlier and more accurately than conventional imaging. Multimodal imaging integrates vascular structure, function, and molecular imaging technology to achieve multi-dimensional imaging, which can be used to comprehensively evaluate blood vessels and obtain clinical information based on anatomical structure and molecular level. At the same time, the rapid development of nonmolecular imaging technologies, such as intravascular imaging, which have the unique advantages of having intuitive accuracy and providing rich information to identify macrophage inflammation and inform targeted personalized treatment, has also been seen. In this review, we highlight recent methods and research hotspots in molecular and nonmolecular imaging of macrophages in atherosclerosis that have enormous potential for rapid clinical application.

Immune-Inflammation in Atherosclerosis: A New Twist in an Old Tale

Background and Objective:

Atherosclerosis, a chronic and progressive inflammatory disease, is triggered by the activation of endothelial cells followed by infiltration of innate and adaptive immune cells including monocytes and T cells in arterial walls. Major populations of T cells found in human atherosclerotic lesions are antigen-specific activated CD4+ effectors and/or memory T cells from Th1, Th17, Th2 and Treg subsets. In this review, we will discuss the significance of T cell orchestrated immune inflammation in the development and progression of atherosclerosis.

Discussion:

Pathogen/oxidative stress/lipid induced primary endothelial wound cannot develop to a full-blown atherosclerotic lesion in the absence of chronically induced inflammation. While the primary inflammatory response might be viewed as a lone innate response, the persistence of such a profound response over time must be (and is) associated with diverse local and systemic T cell responses. The interplay between T cells and innate cells contributes to a phenomenon called immuneinflammation and has an impact on the progression and outcome of the lesion. In recent years immuneinflammation, an old term, has had a comeback in connecting the puzzle pieces of chronic inflammatory diseases.

Conclusion:

Taking one-step back and looking from afar at the players of immune-inflammation may help us provide a broader perspective of these complicated interactions. This may lead to the identification of new drug targets and the development of new therapies as well as preventative measures.