Quantification of low density lipoprotein binding and cholesterol accumulation by single human fibroblasts using fluorescence microscopy.

Using fluorescence microscopy, we have quantified low density lipoprotein (LDL) binding by indirect immunofluorescence and cellular cholesterol with the fluorescent sterol-binding polyene, filipin, in individual cultured human fibroblasts from normal subjects and from patients with heterozygous and homozygous familial hypercholesterolemia. LDL binding by fibroblasts from heterozygous patients was about 40% of that of the normal cells, and cholesterol accumulation upon incubation with LDL was decreased to a similar degree. Most fibroblasts from homozygous patients bound no detectable LDL and only rare cells demonstrated any accumulation of cholesterol after incubation with LDL.