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Validation of a single‐isotope‐labeled cholesterol tracer approach for measuring human cholesterol absorption
Author(s) -
Wang Yanwen,
Vanstone Catherine A.,
Parsons William D.,
Jones Peter J. H.
Publication year - 2004
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-004-1206-6
Subject(s) - cholesterol , chemistry , phytosterol , absorption (acoustics) , isotope , stable isotope ratio , chromatography , medicine , endocrinology , biochemistry , materials science , composite material , physics , quantum mechanics
Abstract Cholesterol absorption is frequently determined using the plasma dual stable‐isotope ratio method (PDSIRM). However, this method involves intravenous injection of stableisotope‐labeled cholesterol with simultaneous oral administration of differently labeled cholesterol, which results in high study costs and involves additional ethical considerations. The objective of the present study was to validate a simpler singleisotope method for determining cholesterol absorption against PDSIRM by using data from two previous studies. Enrichments of carbon‐13 ( 13 C) and deuterium in red blood cells were analyzed by using differential isotope ratio MS. The area under the curve of 13 C‐enrichment in the plasma free‐cholesterol pool was found to be significantly correlated with cholesterol absorption measured by using PDSIRM for study 1 ( r =0.85, P <0.0001) and study 2 ( r =0.81, P <0.0001). Average 13 C‐enrichment correlated with the area under the curve of 13 C‐enrichment in the plasma free cholesterol for both study 1 ( r =0.98, P <0.0001) and study 2 ( r =1.00, P <0.0001). Study 1 examined the efficacy and mechanisms of unesterified plant sterols and stanols on lipid profiles in hypercholesterolemic men and women, while study 2 investigated the effects of phytosterol vs. phytostanol esters on plasma lipid levels and cholesterol kinetics in hyperlipidemic men. Experimental approaches to determine cholesterol absorption were identical between the two studies. Consequently, in both studies, correlations ( r =0.88, P <0.0001 for study 1, and r =0.82, P <0.0001 for study 2) were found between the average 13 C‐enrichment of plasma free cholesterol and cholesterol absorption measured by PDSIRM. These results suggest that a single‐isotope‐labeled cholesterol tracer approach can be used as a reliable noninvasive method to replace PDSIRM for examining changes in cholesterol absorption.