Cellular cholesterol efflux mediated by HDL isolated from subjects with low HDL levels and coronary artery disease.
OBJECTIVE
The aim of this study was to verify whether HDL particles isolated from patients with coronary artery disease (CAD) and low HDL-C had diminished ability to promote cholesterol efflux from cultured cells compared with HDL isolated from subjects without CAD and with normal HDL-C.


METHODS
Smooth muscle cells isolated from human aortas cultured and radiolabeled with H-cholesterol were loaded with cholesterol and incubated with increasing concentrations of HDL isolated from 13 CAD patients with low HDL-C (CAD group) or from 5 controls without CAD (C group). Efflux of cellular cholesterol was measured by cellular depletion of radiolabeled cholesterol and by the appearance of H-cholesterol into experimental medium expressed as a percentage of total labeled cholesterol.


RESULTS
Cholesterol efflux increased with the amount of HDL present in the medium, and no difference was found between groups at various HDL protein concentrations: efflux was 28 +/- 6.3% (C) and 25.5 +/- 8.9% (CAD) with 25 microg/mL; 34 +/- 4.3% (C) and 31.9 +/- 6.6% (CD) with 50 micro g/mL and 39.5 +/- 3.5% (C) and 37.1 +/- 4.4% (CAD) with 100 micro g/mL, HDL.


CONCLUSIONS
Because the HDL fraction of CAD patients with low HDL-C have normal ability to extract cholesterol from cells of the vessel wall, it is suggested that low HDL-C atherogenicity should be ascribed to diminished concentrations of HDL particles rather than to the qualitative properties of the HDL fraction.
Uint
Luciana
L
Heart Institute (InCor), University of São Paulo Medical School, Brazil. dcllucy@incor.usp.br
Sposito
Andrei
A
Brandizzi
Laura Ines Ventura
LI
Yoshida
Vanda Mitie
VM
Maranhão
Raul Cavalcante
RC
Luz
Protásio Lemos da
PL
D000368:Aged; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000097:blood*; D003324:Coronary Artery Disease / Q000097:blood* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*
D008076:Cholesterol, HDL; D002784:Cholesterol