Atherosclerosis is a lipid-driven and an inflammatory disease of the artery walls. The composition of atherosclerotic plaque stratifies the risk of a specific plaque to cause a cardiovascular event. In an optical resolution photoacoustic microscopy setup, of 45 μm resolution, we extracted plaque lipid photoacoustic (PA) spectral signatures of human endarterectomy samples in the range of 1150-1240 nm, using matrix assisted laser desorption ionization mass spectrometry imaging as a reference. We found plaque PA signals to correlate best with sphingomyelins and cholesteryl esters. PA signal spectral variations within the plaque area were compared to reference molecular patterns and absorption spectra of lipid laboratory standards. Variability in the lipid spectroscopic features extracted by principal component analysis of all samples revealed three distinct components with peaks at: 1164, 1188, 1196 and 1210 nm. This result will guide the development of PA-based atherosclerosis disease staging capitalizing on lipidomics of atherosclerotic tissue.
Keywords: Atherosclerosis; CE, cholesteryl ester; CEA, carotid endarterectomy; DG, diacylglycerol; DHB, 2,5-dihydroxybenzoic acid; ESI, electrospray ionization; FTICR, fourier-transform ion cyclotron resonance; HPLC, high-performance liquid chromatography; Lipids; MALDI-MSI, matrix-assisted laser desorption ionization mass spectrometry imaging; Mass spectrometry imaging; Microscopy; NIRS, near-infrared spectroscopy; PC, phosphatidylcholine; PCA; PCA, principal component analysis; PFA, paraformaldehyde; SM, sphingomyelin; Spectroscopy; TG, triacylglycerol; WREnS, Waters Research Enabled Software suite; m/z, mass to charge ratio; μsPA, Micro Spectroscopic Photoacoustic.
© 2021 The Author(s).