Kl. Gillotte et al., DIETARY MODIFICATION OF HIGH-DENSITY-LIPOPROTEIN PHOSPHOLIPID AND INFLUENCE ON CELLULAR CHOLESTEROL EFFLUX, Journal of lipid research, 39(10), 1998, pp. 2065-2075
African green monkeys fed fat-specific diets served as a model to inve
stigate the effect of phospholipid acyl chain modification on high den
sity lipoprotein (HDL)mediated cellular cholesterol efflux, Diets enri
ched in saturated, monounsaturated, n-6 polyunsaturated, or n-3 polyun
saturated fats were provided during both low cholesterol and cholester
ol-enriched stages; sera and HDL3 samples were obtained at specific po
ints during the treatment period. Analysis of the HDL phospholipid com
position revealed significant acyl chain modification, consistent with
the respective fat-specific diet. Cholesterol efflux from mouse L-cel
l fibroblasts to HDL3 isolated from the specific diet groups was measu
red and revealed no differences in the abilities of the particles to a
ccept cellular cholesterol; determination of the bidirectional flux of
cholesterol between the cells and HDL3 species further demonstrated n
o effect of phospholipid acyl chain modification on this process, The
effects of dietary modification of phospholipid acyl chains on cellula
r cholesterol efflux were directly examined by isolating the HDL phosp
holipid and combining it with human apolipoprotein A-I to form well-de
fined reconstituted HDL particles, These complexes did not display any
differences with respect to their ability to stimulate cellular chole
sterol efflux, Incubations with 5% sera further confirmed that the fat
-specific diets do not influence cholesterol efflux. These results sug
gest that the established influences of specific dietary fats on the p
rogression of atherosclerosis are due to effects on cholesterol metabo
lism other than the efflux of cellular cholesterol in the first step o
f reverse cholesterol transport.