Editors' ChoiceAtherosclerosis

Picturing Inflammation in Blood Vessels

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Science Translational Medicine  24 Sep 2014:
Vol. 6, Issue 255, pp. 255ec166
DOI: 10.1126/scitranslmed.3010414

Atherosclerosis—a build-up of fatty material, called plaques, in the arteries—is responsible for a majority of cardiovascular morbidity and mortality. Local vascular inflammation is well established as the critical driver of many atherogenic processes, including cholesterol accumulation and plaque instability. It would therefore be useful to picture all aspects of this inflammation so as to better understand disease progression and its mechanisms. In a new study, van der Valk et al. successfully imaged the involvement of white blood cells early in the process of vascular inflammation in humans.

The investigators first used a clinically approved imaging modality, single-photon emission computed tomography with transmission computed tomography (SPECT/CT), to prove the feasibility of SPECT/CT for visualizing the trafficking of peripheral blood monocytes into atherosclerotic plaques in humans. Among 10 patients with known vascular disease and five healthy volunteers, monocytes were isolated from venous blood samples, labeled with a radioactive isotope, and reinfused. SPECT/CT was used to image the migration of the monocytes into the vascular wall over time. Vascular infiltration by monocytes corresponded to areas of atherosclerosis by means of magnetic resonance imaging and correlated with the degree of vascular wall inflammation by means of positron emission tomography. The kinetics of monocyte trafficking were evaluated, although not fully characterized.

The technique used by van der Valk et al. will allow longitudinal study of the phases of plaque infiltration by monocytes. Different aspects of plaque inflammation have been evaluated in snapshots, but not dynamically, to see leukocyte trafficking characteristics. This new SPECT/CT approach could evaluate the mechanisms of vascular inflammation in a variety of disease states—such as acute myocardial infarction, acute stroke, chronic atherosclerotic vascular disease, and chronic aneurysmal vascular disease—providing not only mechanistic insights, but also the ability to evaluate new therapies.

F. M. van der Valk et al., In vivo imaging of enhanced leukocyte accumulation in atherosclerotic lesions in humans. J. Am. Coll. Cardiol. 64, 1019–1029 (2014). [Abstract]

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