FTIR Spectroscopic Imaging Applied to Atherosclerosis

The programme of work will develop the application of Fourier Transform infrared (FTIR) imaging to atherosclerosis. FTIR imaging can be thought of as chemical photography whereby each pixel within an image corresponds to a complete FTIR spectrum that reflects the chemical composition at that point. FTIR imaging has enabled us to generate chemical images of healthy and atherosclerotic arterial tissue based on the absorbance of IR bands that correspond to specific lipid and protein components within the sample. Our preliminary work has already demonstrated the feasibility of using Attenuated Total Reflectance (ATR)-FTIR spectroscopic imaging for studying arteries and atherosclerotic plaques. The enhanced spatial resolution that was achieved with micro ATR imaging (ca. 3 microns) will be used to analyse arterial samples in greater spatial and chemical detail, whilst the use of artificial neural networks and/or clustering analysis for multivariate treatment of imaging data will allow greater discrimination of different chemical species. We also aim to build a system that will enable us to use macro ATR-FTIR imaging to directly measure diffusion of model drug molecules and native lipoproteins into and across samples of arterial wall from the distribution of drug and characteristic lipoprotein IR bands at different timepoints. The data obtained will define the partitioning and spatial distribution of drugs in arterial samples. The ability to chemically image microscopic histological components within the plaque is an invaluable tool in order to further the understanding of the role lipoproteins and drugs play in disease progression and/or regression.