Imaging the lipidome in atherosclerosis

Tissue composition is a key factor in the assessment of atherosclerotic plaque risk, and we have developed photoacoustic (PA) imaging as a technology to quantify plaque lipid. Close scrutiny of the optical absorption data acquired by PA imaging revealed small but consistent variations in the spectra within and between plaques. This inspired a search for the molecular ground truth underlying these spectral variations. We studied ex-vivo human (and porcine) atherosclerotic plaques with lipidomic (mass spectrometry) imaging, a form of label-free chemical microscopy that can identify hundreds of lipids at a resolution of tens of microns. We were able to link the occurrence of specific lipids to features of plaque vulnerability and atherogenic processes such as calcification and inflammation. In this talk, I will review our findings, discuss their implications for plaque biology, and look ahead towards potential real-world utility of imaging lipidomics.