Oxidation of Cholesteryl Linoleate by Human Monocyte-macrophages in Vitro

The amount of cholest-5-en-3 beta,7 beta-diol (CD) was significantly higher in cultures of human monocytes incubated with cholesteryl linoleate-bovine serum albumin (CL/BSA) artificial lipoproteins than in no-cell control incubations of CL/BSA. CD production by monocytes was almost completely inhibited by the radical scavengers butylated hydroxytoluene (BHT), probucol, and alpha-tocopherol, and was partially inhibited by the metal chelator EDTA. The production of CD was accompanied by decrease in linoleic acid. CD amounts were negligible in incubations of monocytes with cholesteryl oleate/BSA (CO/BSA) or cholesterol/BSA (C/BSA). Ability to produce CD from CL/BSA appeared to increase with age in culture of human monocyte-macrophages. Considerable variations were observed in the CD production from CL/BSA by monocytes from different blood donations. Higher levels of CD production appeared more common with monocytes from men than from women. The significance of these results in the context of human atherosclerosis is discussed.