title: Lipoprotein distribution and biological variation of 24S- and 27-hydroxycholesterol in healthy volunteers.
abstract: 24S- and 27-hydroxycholesterol are obligatory intermediates of cholesterol catabolism and play an important role in the maintenance of whole-body cholesterol homeostasis. Using an HPLC-MS method for oxysterol quantification, the distribution of esterified and unesterified oxysterols in lipoprotein subfractions as well as the influence of daytime, food intake and menstrual cycle on oxysterol concentrations were investigated in healthy volunteers. Moreover, reference intervals for 24S- and 27-hydroxycholesterol in plasma as well as the corresponding levels for 27-hydroxycholesterol in the HDL subfraction were established in 100 healthy volunteers. Both circulating oxysterols are mainly transported in association with HDL and LDL--primarily in the esterified form. No significant diurnal changes and no variations during menstrual cycle of either absolute or cholesterol-related plasma levels were detected. In contrast to 24S-hydroxycholesterol in plasma and 27-hydroxycholesterol in the HDL subfraction, the 95% reference intervals of 27-hydroxycholesterol both in plasma and the non-HDL subfraction were higher in males than in females. The concentrations of 27-hydroxycholesterol in plasma and the non-HDL subfraction showed strong positive correlations with the concentrations of cholesterol, non-HDL cholesterol and triglycerides. Our data on the lipoprotein distribution of oxysterols as well as on their intra- and inter-individual variation set the stage for future clinical studies.
authors.affiliation: Institute of Clinical Chemistry, Center for Integrative Human Physiology, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Ines
authors.initials: I
authors.lastname: Burkard
authors.forename: Arnold
authors.initials: A
authors.lastname: von Eckardstein
authors.forename: Gérard
authors.initials: G
authors.lastname: Waeber
authors.forename: Peter
authors.initials: P
authors.lastname: Vollenweider
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Rentsch
mesh_terms: D000328:Adult; D000368:Aged; D002624:Chemistry, Clinical / Q000379:methods* / Q000592:standards*; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D002940:Circadian Rhythm; D004951:Esterification; D005260:Female; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood*; D008297:Male; D008597:Menstrual Cycle / Q000097:blood; D008875:Middle Aged; D012016:Reference Values; D014280:Triglycerides / Q000097:blood
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D006888:Hydroxycholesterols; D014280:Triglycerides; C044563:24-hydroxycholesterol; C076996:27-hydroxycholesterol