Use of Nile red stain in the detection of cholesteryl ester accumulation in acid lipase-deficient fibroblasts

Abstract

The fluorescent hydrophobic probe Nile red was used to distinguish between normal human fibroblasts and fibroblasts from individuals with a genetic deficiency in lysosomal acid lipase activity (Wolman's disease and cholesteryl ester storage disease). The fluorescence of Nile red-stained cultured mutant cells, indicative of neutral lipid accumulation, was intense when compared microscopically with normal fibroblasts. The cholesteryl ester accumulation in the acid lipase-deficient fibroblasts was demonstrated qualitatively and quantitatively when cellular lipid extracts were subjected to thin-layer chromatography, followed by Nile red plate treatment and fluorescence spectrometry scanning. These results demonstrate the utility of the Nile red stain to document cellular lipid overloading. The techniques are simple to perform and can effectively supplement the standard enzymatic analysis used in the diagnosis of acid lipase deficiency.