Longitudinal in vivo monitoring of atheroprogression in hypercholesterolemic mice using photoacoustic imaging.

Background and aim- The ability to recognize and monitor atherosclerotic lesion development using non-invasive imaging is crucial in preventive cardiology. The aim of the present study was to establish a protocol for longitudinal monitoring of plaque lipid, collagen and macrophage burden as well as of endothelial permeability. Methods and results- Photoacoustic signals derived from endogenous or exogenous dyes assessed in vivo, in plaques of albino Apoe-/- mice, correlated with lesion characteristics obtained after histomorphometric and immunofluorescence analyses thus supporting the validity of our protocol. Using models of atheroprogression and -regression we could apply our imaging protocol to the longitudinal observation of atherosclerotic lesion characteristics in mice. Conclusions- The present study shows an innovative approach to assess arterial inflammation in a non-invasive fashion, applicable to longitudinal analyses of changes of atherosclerotic lesion composition. Such approach could prove important in the preclinical testing of therapeutic interventions in mice carrying pre-established lesions.