Keywords: 24S-OHC; 24S-hydroxycholesterol; 27-OHC; 27-hydroxycholesterol; Aβ peptides; β-amyloid peptides; ABCA1, ABCB1 and ABCG1; ATP-binding cassette (ABC) subfamily A, member 1, ABC subfamily B, member 1 and ABC subfamily G, member 1, respectively; AD; Alzheim