QUANTITATIVE-ANALYSIS OF CHOLESTEROL AND CHOLESTERYL ESTERS IN HUMAN ATHEROSCLEROTIC PLAQUES USING NEAR-INFRARED RAMAN-SPECTROSCOPY

Raman spectroscopy is a non-destructive analytical technique and previ ous results have shown that qualitative analysis of the lipid componen t of human atheromatous arteries is feasible. In this paper, we descri be a quantitative analytical method for cholesterol and cholesteryl ea ters in human atherosclerotic plaques, combined with Raman spectroscop ic results, using partial least-squares (PLS) regression, a statistica l multivariate method based on factorial analysis. Twenty-nine human a therosclerotic pooled samples were studied and the results of Raman sp ectroscopy coupled with the PLS method were compared to biochemical re sults. The standard error of prediction was 16.1, 13.6, 1.9, 3.3 and 3 .3 mg/g for total cholesterol, free cholesterol, palmitate cholesteryl , oleate cholesteryl and linoleate cholesteryl, respectively. The repe atability of Raman spectroscopy was found to be excellent. Our results show that Raman spectroscopy is a promising technique to obtain a con sistent and non-destructive quantitative analysis of cholesterol and c holesteryl esters in human atherosclerotic lesions. In situ and in viv o analysis is a possibility in the near future. (C) 1998 Elsevier Scie nce Ireland Ltd. All rights reserved.